ARRANGEMENT

                           INVOLVING

            MacDONALD, DETTWILER AND ASSOCIATES LTD.

                      3173623 CANADA INC.

                              AND

                  ORBITAL SCIENCES CORPORATION







         NOTICE OF SPECIAL MEETING OF SHAREHOLDERS AND
       HOLDERS OF THE 1988 EMPLOYEE SHARE OPTIONS AND THE
               1988 KEY EMPLOYEE SHARE OPTIONS OF
            MacDONALD, DETTWILER AND ASSOCIATES LTD.


                              AND


                MANAGEMENT INFORMATION CIRCULAR


                        OCTOBER 6, 1995


[MDA LETTERHEAD]


October 10, 1995

Dear Shareholder or Optionholder:

You  are cordially invited to attend a Special Meeting of Shareholders  and
holders  of 1988 Employee Share Options and 1988 Key Employee Share Options
(collectively,  the "MDA 1988 Optionholders") of MacDonald,  Dettwiler  and
Associates Ltd. ("MDA") to be held on Tuesday, November 14, 1995  at  MDA's
offices  located at 13800 Commerce Parkway, Richmond, British  Columbia  at
10:00 a.m. local time.  As described in the enclosed Proxy Circular, at the
Special  Meeting, the MDA Shareholders and MDA 1988 Optionholders  will  be
asked  to  consider and vote upon an Arrangement under section 192  of  the
Canada Business Corporation Act involving MDA, Orbital Sciences Corporation
("Orbital"),  and  317632  Canada  Inc.  ("Acquisition"),  a  wholly  owned
subsidiary  of Orbital.  Subject to any further order of the Supreme  Court
of British of Columbia, the Arrangement must be approved by the affirmative
vote of 66-2/3% of the votes actually cast thereon by MDA Shareholders  and
by MDA 1988 Optionholders, voting as separate classes.

The  MDA Board of Directors has carefully reviewed and considered the terms
and  conditions  of  the  proposed Arrangement.   The  Board  of  Directors
believes that the transaction is fair and in the best interests of MDA, MDA
Shareholders  and MDA 1988 Optionholders, and has unanimously approved  the
Arrangement.   The Board of Directors unanimously recommends that  the  MDA
Shareholders  and MDA 1988 Optionholders vote FOR the proposed  Arrangement
Resolution approving the Arrangement.

Under  the  Plan  of Arrangement, MDA will receive Exchangeable  Shares  of
Acquisition, which will have voting, dividend and liquidation  rights  that
are,  as  nearly  as  practicable, equivalent to those  of  Orbital  Common
Shares.  The number of Exchangeable Shares to be issued will be based  upon
an  Exchange  Ratio that is to be determined by dividing U.S.$5.41  by  the
average  closing  sale price of Orbital Common Shares for  the  twenty  day
period  ending  on the date four trading days prior to the Effective  Date,
and  may not be less than .2705 or greater than .3607.  The Effective  Date
is  expected  to occur shortly after the Special Meeting.  MDA Shareholders
will receive the number of Exchangeable Shares equal to the product of  the
Exchange Ratio multiplied by the number of MDA Common Shares held by  them.
Holders   of  MDA  Options,  including  MDA  1988  Options,  will   receive
Replacement  Options  entitling them to purchase  such  number  of  Orbital
Common Shares equal to the product of the Exchange Ratio multiplied by  the
number  of MDA Common Shares underlying such MDA Option, having an exercise
price  per share equal to the quotient of the exercise price per  share  of
such MDA Option divided by the Exchange Ratio, and having the same vesting,
expiration and other terms as such MDA Option.

The  accompanying  Proxy Circular provides a detailed  description  of  the
Arrangement and the business and financial information of MDA and Orbital.

MDA  retained  the investment banking firm of Nesbitt Burns Inc.  ("Nesbitt
Burns") to advise it on the acquisition transaction, including to advise it
with respect to the consideration to be paid by Orbital in the Arrangement.
Nesbitt  Burns  has  advised the MDA Board of Directors  that,  in  Nesbitt
Burns'  opinion, the consideration to be paid by Orbital in the Arrangement
is  fair  to  MDA Shareholders and MDA 1988 Optionholders from a  financial
point  of view.  A copy of Nesbitt Burns' opinion is attached to the  Proxy
Circular as Appendix "C".

Your  vote  on  this  matter is very important.   We  urge  you  to  review
carefully  the  enclosed  materials and  to  return  your  proxy  promptly.
Shareholders  with questions regarding the Arrangement  or  other   matters
described herein may contact Gordon Thiessen at (604) 278-3411.

Whether  or  not  you plan to attend the Special Meeting, please  sign  and
promptly return your proxy card in the enclosed postage paid envelope.   If
you attend the meeting, you may vote in person if you wish, even though you
have previously returned your proxy.

Sincerely,

/s/ John S. MacDonald                   /s/ Daniel E. Friedman

John S. MacDonald, Chairman             Daniel E. Friedman, President and
CEO
                                


                NOTICE OF SPECIAL GENERAL MEETING

NOTICE   IS   HEREBY   GIVEN   that   a  Special   General   Meeting   (the
"Special    Meeting")   of   holders   of   MDA   Common    Shares    ("MDA
Shareholders")   and   holders  of  options  ("MDA   1988   Optionholders")
under   the   1988   Employee  Share  Option  Plan   and   the   1988   Key
Employee   Share  Option  Plan  (together,  the  "MDA  1988  Options")   of
MacDonald,  Dettwiler  and  Associates  Ltd.  ("MDA")  will  be   held   at
the   offices   of  MDA  at  13800  Commerce  Parkway,  Richmond,   British
Columbia,  V6V  2J3,  on  Tuesday,  November  14,  1995  at  the  hour   of
10:00 a.m. (Vancouver time) for the following purposes:

(a)  to   consider,  pursuant  to  an  order  of  the  Supreme   Court   of
     British    Columbia    dated   October   6,   1995    (the    "Interim
     Order"),   and,  if  deemed  advisable  to  pass,  with   or   without
     variation,      a     special     resolution     (the     "Arrangement
     Resolution")   to   approve   an   arrangement   (the   "Arrangement")
     under   section   192   of  the  Canada  Business  Corporations   Act;
     and

(b)  to   transact   such  further  or  other  business  as  may   properly
     come before the Special Meeting or any adjournment thereof.

The   texts   of  the  Arrangement  Resolution,  the  Plan  of  Arrangement
and  the  agreements  in  respect  of the  Arrangement  are  set  forth  in
Appendices   "F,"   "A"   and  "B,"  respectively,  to   the   accompanying
Management Information Circular of MDA (the "Proxy Circular").

Pursuant  to  the  Interim  Order,  MDA  Shareholders  and  the  MDA   1988
Optionholders  have  been  granted  the  right  to  dissent  with   respect
to   the  Arrangement  and  to  be  paid  the  fair  value  of  their   MDA
Common  Shares  or  the  MDA  Common Shares  to  which  they  are  entitled
under  the  MDA  1988  Options, as the case  may  be,  in  respect  of  the
Arrangement   Resolution   in  accordance   with   section   190   of   the
Canada  Business  Corporations  Act.   This  right  is  described  in   the
Proxy Circular.

The   Board  of  Directors  has  fixed  October  10,  1995  as  the  record
date   for   determining  MDA  Shareholders  entitled  to  receive   notice
of   and  to  vote  at  the  Meeting.   Only  holders  of  record  of   MDA
Common  Shares  at  the  close  of  business  on  October  10,  1995   will
be  entitled  to  vote  in  respect of  the  matters  to  be  voted  on  at
the   Special   Meeting  or  any  adjournment  thereof,   except   that   a
person   who   has   acquired  MDA  Common  Shares   subsequent   to   such
record  date  will  be  entitled  to  vote  such  shares,  instead  of  the
holder   of   record,  upon  making  a  written  request  to  that   effect
not  later  than  10  days  preceding  the  date  of  the  Special  Meeting
to  the  Secretary  of  MDA  at  the  registered  office  of  MDA  at  26th
floor,    700   West   Georgia   Street,   Vancouver,   British   Columbia,
V7Y   1B3  and  establishing  that  such  person  owns  such  shares.   All
MDA   1988   Optionholders   on  the  date  of   mailing   of   the   Proxy
Circular  will  receive  Notice  of  the  Special  Meeting  and   all   MDA
1988   Optionholders  on  the  date  of  the  Special   Meeting   will   be
entitled to attend and vote at the Special Meeting.

MDA   Shareholders   and  MDA  1988  Optionholders  who   are   unable   to
attend  the  Special  Meeting  in  person  are  requested  to  sign,   date
and   return,   in   the   envelope  provided   for   that   purpose,   the
enclosed  instrument  of  proxy.   In  order  to  be  valid  for   use   at
the   Special   Meeting,  proxies  must  be  received  by  Montreal   Trust
Company    of    Canada,    510   Burrard   Street,   Vancouver,    British
Columbia,   V6C   3B9   not  less  than  48  hours  (excluding   Saturdays,
Sundays   and   holidays)   preceding   the   Special   Meeting   or    any
adjournment thereof.

DATED   at   Richmond,  British  Columbia,  this  6th   day   of   October,
1995.


                               BY ORDER OF THE BOARD OF DIRECTORS




                                      ROBERT B. WALLIS, Secretary

                       TABLE OF CONTENTS

                                                             Page



MANAGEMENT INFORMATION CIRCULAR                                 1

GLOSSARY OF TERMS                                               2

MDA AND ORBITAL REPORTING CURRENCIES AND ACCOUNTING PRINCIPLES  7

CANADIAN/U.S. EXCHANGE RATES                                    7

SUMMARY OF PROXY CIRCULAR                                       8
          General                                               8
          The Arrangement and The Combination Agreement         8
          Certain Canadian Federal Income Tax Considerations   11
          Certain   United   States  Federal  Income
          Tax   Considerations                                 12
          The Special Meeting                                  13
          Business of Orbital                                  14
          Business of MDA                                      16

MARKET PRICE AND DIVIDEND INFORMATION                          17

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA                18
          Selected Historical Consolidated Financial Data of
          MDA                                                  18
          Selected    Historical    Consolidated
          Financial    Data    of       Orbital                19

PRO FORMA FINANCIAL INFORMATION                                20

PRO FORMA CONSOLIDATED CAPITALIZATION                          27

RISK FACTORS                                                   28
          Technologically Advanced Products and Services       28
          Dependence on United States Government               28
          Capital Requirements                                 28
          Regulation                                           29

THE SPECIAL MEETING - GENERAL PROXY INFORMATION                30
          General                                              30
          Solicitation of Proxies                              30
          Appointment of Proxies                               30
          Signing of Proxies                                   30
          Revocation of Proxies                                30
          Voting of Proxies                                    31
          MDA Common Shares                                    31
          MDA 1988 Options                                     31
          Required   Votes   to   Approve  the   Arrangement
          and   Voting  Intentions of Certain Shareholders
          and Optionholders                                    31
          Principal   Holders   of  MDA  Common   Shares
          and   MDA   1988    Options                          32

THE ARRANGEMENT AND THE COMBINATION AGREEMENT                  32
          The Arrangement - General                            32
          Background of the Arrangement                        33
          MDA's   Reasons   for   the   Arrangement   and
          Recommendations of the MDA Board                     35
          Orbital's Reasons for the Arrangement                35
          Operations Following the Arrangement                 36
          Interests of Certain Persons in the Arrangement      36
          Opinion of MDA's Financial Advisor                   36
          Plan of Arrangement                                  39
          Post-Combination Share Ownership                     40
          Qualifying Holdcos                                   40
          Dissenting Holders                                   40
          Description of Exchangeable Shares                   40
                Voting Rights                                  41
                Dividend Rights                                41
                Retraction, Redemption and Exchange Right      42
                Deduction and Remittance of Withholding Tax    43
                Anti-dilution and Capital Reorganizations      44
          Support Agreement                                    44
          Market    for    Orbital   Common   Shares
          and    Exchangeable   Shares                         45
          The Combination Agreement                            45
                  Actions to be Taken Prior to the Effective
                  Time                                         45
                  Business of MDA Pending the Arrangement      45
                  Solicitation of Alternate Transactions       46
                  Conditions to the Arrangement                46
                  Termination and Amendment                    47
                   Fees, Expenses and  Indemnification         47
          Confidentiality Agreement                            48
          Agreements of MDA Affiliates                         48
          Court Approval and Completion of the Arrangement     48
          Accounting Treatment                                 49
          Stock Exchange Listings                              49
                 Exchangeable Shares                           49
                 Orbital Common Shares                         49
          Eligibility for Investment in Canada                 49
                 Exchangeable Shares                           49
                 Voting Rights and Exchange Right              49
                 Orbital Common Shares                         49
          Resale   of   Exchangeable  Shares  and  Orbital
          Common   Shares  Received in the Arrangement         50
                 Canada                                        50
                 United States                                 50
          Procedures   for   Exchange   of  Share
          Certificates   by   MDA   Shareholders               51
               Return to Depositary of Letter of Transmittal   51
               Election to Immediately Exchange
               Exchangeable Shares for Orbital Common Shares   51
               Fractional Shares                               52
               Failure to Deposit Certificates Representing
               MDA Common Shares                               52
          Confirmation of Replacement Options                  52

INCOME TAX CONSIDERATIONS TO MDA SHAREHOLDERS AND
        OPTIONHOLDERS                                          52
          Canadian Federal Income Tax Considerations           52
          Holders of MDA Common Shares Resident in Canada      53
          Holders of MDA Common Shares Not Resident in Canada  57
                MDA 1988 Optionholders                         58
          United States Federal Income Tax Considerations      58
          Taxation of U.S. Holders                             59
          Shareholders Not Resident in or Citizens of the
                United States                                  62
          Information, Reporting and Backup Withholding        63

INFORMATION CONCERNING ACQUISITION                             63

INFORMATION CONCERNING ORBITAL                                 63
          Background and Recent Acquisitions                   63
          Description Of Orbital's Products And Services       64
               Launch Systems                                  65
               Space and Electronics Systems                   66
               Communications and Information Systems          67
          Competition                                          70
          Research and Development                             71
          Backlog and Contracts                                71
          Properties                                           72
          Environmental Regulation                             73
          Insurance                                            73
          Litigation                                           73
          Management's    Discussion    and    Analysis    of
             Financial Condition and Results of Operations     73
                 Overview                                      73
                 Adoption of New Accounting Standard           74
               Results of Operations for the Six-Month Periods
                        Ended June 30, 1995 and 1994           76
               Results of Operations for the Years Ended
                December 31, 1994, 1993 and 1992               77
               Liquidity and Capital Resources                 79
          Management and Employees                             80
              Executive Officers and Directors                 80
              Indebtedness of Directors and Officers           81
              Employees                                        81
          Description of Capital                               82
              Capitalization                                   82
              Common Shares                                    82
              Preferred Shares                                 82
          Dividend Policy                                      83
          Transfer Agent                                       83
          Independent Auditors                                 83

INFORMATION CONCERNING MDA                                     83
          Business                                             83
                Subsidiary Companies                           83
                General                                        84
                Geo-Information Systems                        84
                Aviation Systems                               85
                Space and Defence Systems                      86
                Communications                                 87
          Contract Pricing and Completion                      87
          Marketing and Sales                                  87
          Competition                                          89
          Research and Development                             89
          Patents and Licenses                                 89
          Personnel                                            90
          Properties                                           90
          Management's    Discussion    and    Analysis    of
             Financial Condition and Results of Operations     90
               Results of Operations for the Quarter ended
               June 30, 1995 and Quarter Ended June 30, 1994   90
               Results of Operations for the Fiscal Years
               ended March 31, 1995 and 1994                   90
               Results of Operations for the Fiscal Years ended
                March 31, 1994 and 1993                        91
          Directors and Officers                               92
          Description of Share Capital                         93
          Dividend Record and Dividend Policy                  93
          Executive Compensation                               94
              Summary Compensation Table                       94
              Long-Term Incentive Plan Compensation            94
              Pensions                                         95
          Auditors                                             95
          Registrar and Transfer Agent                         96
          Stock Exchange Listings                              96

COMPARISON OF SHAREHOLDERS' RIGHTS                             96
          Extraordinary Transactions - Vote Required           96
          Amendment to Governing Documents                     97
          Dissent Rights                                       98
          Oppression Remedy                                    98
          Derivative Action                                    99
          Shareholder Consent in Lieu of Meeting               99
          Director Qualifications                              99
          Fiduciary Duties of Directors                        99
          Indemnification of Officers and Directors           100
          Director Liability                                  100
          Anti-takeover     Provisions    and    Interested
           Stockholder     Transactions                       100
          Shareholder Protection Rights Plan                  101

DISSENTING RIGHTS                                             101

AVAILABLE INFORMATION                                         104

LEGAL MATTERS                                                 104

APPROVAL OF PROXY CIRCULAR BY MDA BOARD OF DIRECTORS          104

ANNEX "I"      Orbital's Consolidated Financial Statements and
                Quarterly Report on Form 10-Q for the
                Quarter Ended June 30, 1995                     F-1 (OMITTED)

ANNEX "II"      MDA's Financial Statements                      F-39 (OMITTED)
ANNEX "III"    Excerpt of Orbital's Proxy Statement for 1995
                Annual Meeting of Stockholders                  P-1 (OMITTED)
APPENDIX "A"   Plan of Arrangement                              A-1
APPENDIX "B"   Combination Agreement                            B-1
APPENDIX "C"   Opinion of Nesbitt Burns                         C-1 (OMITTED)
APPENDIX "D"   Interim Order                                    D-1 (OMITTED)
APPENDIX "E"   Notice    of   Application   for   Final   Order
               to the Supreme Court (British Columbia)          E-1 (OMITTED)
APPENDIX "F"   Arrangement Resolution                           F-1 (OMITTED)
APPENDIX "G"   Section 190 of the CBCA                          G-1 (OMITTED)


            MacDONALD, DETTWILER and ASSOCIATES LTD.
                                
                                
                 MANAGEMENT INFORMATION CIRCULAR
                                
                                

This   Proxy   Circular   is  being  furnished   to   holders   of   Common
Shares   of  MDA  and  MDA  1988  Optionholders  in  connection  with   the
solicitation   of   proxies  by  management  of  MDA   for   use   at   the
Special  Meeting  to  be  held  at  10:00 a.m.,  local  time,  on  Tuesday,
November   14,   1995,   at   the  offices  of  MDA   at   13800   Commerce
Parkway,    Richmond,   British   Columbia,   V6V   2J3,   and    at    any
adjournment thereof.

At    the    Special    Meeting,   MDA   Shareholders    and    MDA    1988
Optionholders  will  be  asked  to  consider  and  vote  upon  a   proposal
to  approve  an  arrangement  under  section  192  of  the  CBCA  involving
MDA   and   its  shareholders  and  optionholders  and  to  transact   such
further  or  other  business  as  may  properly  come  before  the  meeting
or any adjournment thereof.

MDA   Shareholders  and  MDA  1988  Optionholders  are   being   asked   to
approve    the   Arrangement   under   the   CBCA.    Pursuant    to    the
Arrangement,    MDA   will   become   a   wholly   owned   subsidiary    of
Acquisition   and   each   outstanding   MDA   Common   Share    will    be
exchanged   for   a   number   of  Exchangeable   Shares   of   Acquisition
equal   to   the   Exchange   Ratio.    The   Exchange   Ratio   will    be
determined   by   dividing  US$5.41  by  the  average  closing   price   of
Orbital  Common  Shares  for  the  20  trading  days  ending  on  the  date
four  trading  days  prior  to  the  Effective  Date  of  the  Arrangement,
provided  that  the  Exchange  Ratio  will  not  be  less  than  0.2705  or
greater    than    0.3607.    Outstanding   MDA   Options    will    become
Replacement   Options   to   acquire  Orbital  Common   Shares   on   terms
identical    to    the    existing    MDA   Options,    with    appropriate
adjustments   in   the   exercise  price   and   the   number   of   shares
subject   to   such   options   to  reflect  the   Exchange   Ratio.    The
Exchangeable   Shares   will   have  voting,   dividend   and   liquidation
rights   that   are,  as  nearly  as  practicable,  equivalent   to   those
rights of the Orbital Common Shares.

Holders   of   Exchangeable  Shares  will  have  the  right   to   exchange
all   or   any   of   such   shares  for  an  equal  number   (subject   to
adjustment    in    the   event   of   certain   capital   and    corporate
reorganizations)   of   Orbital   Common   Shares   plus    the    Dividend
Amount   attributable  to  such  shares,  at  any   time   prior   to   the
Automatic   Redemption  Date  and  subject  to  certain  Call   Rights   of
Orbital.    The   Exchangeable  Shares  will  be  automatically   exchanged
on   the   Automatic   Redemption  Date  and   upon   the   occurrence   of
certain   events,  including  the  liquidation,  dissolution  or   winding-
up   of  Orbital  or  Acquisition  or  the  default  by  Acquisition  under
the   Exchangeable  Share  Provisions.   Acquisition  has  the   right   to
accelerate   the   Automatic  Redemption  Date  upon   75   days'   written
notice   to   the  holders  of  Exchangeable  Shares  at  any   time   when
there   are   outstanding  less  than  400,000  Exchangeable  Shares   held
by persons other than Orbital and its Affiliates.

                                

This   Proxy   Circular  and  the  accompanying  forms  of  proxy,   Letter
of   Transmittal  and  Notice  of  Guaranteed  Delivery  are  first   being
mailed  to  MDA  Shareholders  and  MDA  1988  Optionholders  on  or  about
October 11, 1995.

                                

All   information  in  this  Proxy  Circular  relating  to  MDA  has   been
supplied   by   MDA.    All  information  relating  to   Orbital   Sciences
Corporation    and    Acquisition   has   been   supplied    by    Orbital.
Orbital   has   reviewed   all   information   relating   to   itself   and
Acquisition  after  its  inclusion  in  this  Proxy  Circular.    MDA   has
not    made    any    independent    investigations    and    assumes    no
responsibility    for    the    accuracy   or    completeness    of    such
information.     Certain   capitalized   terms   used   in    this    Proxy
Circular   without   definition   have   the   meanings   given   in    the
Glossary of Terms found at page 2.

See   "Risk   Factors"   for  certain  considerations   relevant   to   MDA
Shareholders   and  MDA  1988  Optionholders  regarding   the   Arrangement
and their investment in the securities referred to herein.

No   person  is  authorized  to  give  any  information  or  to  make   any
representation  not  contained  in  this  Proxy  Circular  and,  if   given
or   made,  such  information  or  representation  should  not  be   relied
upon   as   having   been  authorized.   This  Proxy  Circular   does   not
constitute   an  offer  to  sell,  or  a  solicitation  of  an   offer   to
purchase,  any  securities,  or  the  solicitation  of  a  proxy,  by   any
person  in  any  jurisdiction  in  which  such  an  offer  or  solicitation
would   be   unlawful  or  in  which  the  person  making  such  offer   or
solicitation  is  not  qualified  to  do  so  or  to  any  person  to  whom
it  is  unlawful  to  make  such  an offer  or  solicitation  of  an  offer
to   purchase   or   proxy   solicitation.   Neither   delivery   of   this
Proxy  Circular  nor  any  distribution  of  the  securities  referred   to
in   this  Proxy  Circular  shall,  under  any  circumstances,  create   an
implication  that  there  has  been  no  change  in  the  information   set
forth herein since the date of this Proxy Circular.
                        GLOSSARY OF TERMS

The  following  terms  have  the  following  meanings  when  used  in  this
Proxy   Circular  (including  the  summary).   These  defined   terms   are
not   used   in  the  consolidated  financial  statements  of  either   MDA
or Orbital attached as annexes hereto.

"1933   Securities  Act"  means  the  United  States  Securities   Act   of
1933,   including   all   regulations  made  thereunder,   all   amendments
to  such  statute  or  regulations from  time  to  time,  and  any  statute
or   regulation   that   supplements  or   supersedes   such   statute   or
regulation.

"1934   Securities  Exchange  Act"  means  the  United  States   Securities
Exchange   Act   of  1934,  including  all  regulations  made   thereunder,
all   amendments  to  such  statute  or  regulations  from  time  to  time,
and   any  statute  or  regulation  that  supplements  or  supersedes  such
statute or regulation.

"Acquisition"   means   3173623   Canada   Inc.,   a   newly   incorporated
subsidiary of Orbital, existing under the CBCA.

"Acquisition   Class   B   Preferred   Shares"   means    the    Class    B
Preferred   Shares   of   Acquisition  having   the   rights,   privileges,
restrictions  and  conditions  set  forth  in  Appendix  A  to   the   Plan
of Arrangement.

"Acquisition    Common    Shares"    means    the    Common    Shares    of
Acquisition    having    the   rights,   privileges,    restrictions    and
conditions set forth in Appendix A to the Plan of Arrangement.

"Affiliate"   of   any   person  means  any  other   person   directly   or
indirectly   controlling,   controlled  by,   or   under   common   control
with,    that    person.    For   the   purposes   of   this    definition,
"control"    (including,    with   correlative    meanings,    the    terms
"controlling,"   "controlled  by"  and  "under   common   control   with"),
as  applied  to  any  person,  means  the  possession  by  another  person,
directly   or   indirectly,  of  the  power  to   direct   or   cause   the
direction   of  the  management  and  policies  of  that  first   mentioned
person,   whether   through  the  ownership  of   voting   securities,   by
contract or otherwise.

"Affiliate   Agreements"  means  the  agreements   entered   into   between
Orbital   and   persons   who  are  deemed  to  be  "affiliates"   of   MDA
within   the   meaning  of  the  1933  Securities  Act,  substantially   in
the    forms   attached   as   Exhibits   6.2.4(A)   and   (B)    to    the
Combination Agreement.

"Arrangement"  means  the  arrangement  under  section  192  of  the   CBCA
on  the  terms  and  subject to the conditions  set  out  in  the  Plan  of
Arrangement,   subject  to  any  amendments  thereto  made  in   accordance
with   section   6.1  of  the  Plan  of  Arrangement   or   made   at   the
direction of the Court in the Final Order.

"Arrangement    Resolution"   means   the   resolution    concerning    the
Arrangement  in  the  form  set  forth  in  Appendix  "F"  to  this   Proxy
Circular.

"Automatic   Redemption   Date"  means  the  fifth   anniversary   of   the
Effective  Date,  unless  such  date  shall  be  accelerated  at  any  time
to   a   specified   earlier   date  by   the   board   of   directors   of
Acquisition   upon  at  least  75  days'  prior  written  notice   to   the
registered   holders   of   Exchangeable  Shares,   in   which   case   the
Automatic   Redemption   Date  shall  be  such  earlier   date;   provided,
however,   that   the   board   of  directors   of   Acquisition   may   so
accelerate   the   Automatic  Redemption  Date  only  at   such   time   as
there   are  outstanding  fewer  than  400,000  Exchangeable  Shares   held
by holders other than Orbital and its Affiliates.

"Average   Closing  Price"  means  the  average  closing  sales  price   of
Orbital  Common  Shares  for  the  20  trading  days  ending  on  the  date
four   trading   days  prior  to  the  Effective  Date,  as   reported   on
NASDAQ.

"Business  Day"  means  any  day other than  a  Saturday,  a  Sunday  or  a
day  when  banks  are  not  open for business in  either  or  both  of  the
Commonwealth of Virginia and Vancouver, British Columbia.

"CBCA"   means   the  Canada  Business  Corporations  Act,   R.S.C.   1985,
c.C-44,   including  all  regulations  made  thereunder,   all   amendments
to  such  statute  or  regulations from  time  to  time,  and  any  statute
or   regulation   that   supplements  or   supersedes   such   statute   or
regulation.

"Call   Rights"  means  collectively,  the  Liquidation  Call  Right,   the
Redemption Call Right and the Retraction Call Right.

"Canadian   dollars"  and  "Cdn$,"  "dollars"  and  "$"  mean  the   lawful
currency of Canada.

"Canadian   GAAP"  means  generally  accepted  accounting   principles   in
Canada.

"Canadian   Tax   Act"   means  the  Income  Tax   Act   (Canada),   R.S.C.
1985,    c.1    (5th   Supplement),   including   all   regulations    made
thereunder,   all   amendments  to  such  statute   or   regulations   from
time   to  time,  and  any  statute  or  regulation  that  supplements   or
supersedes such statute or regulation.

"Change   of  Control  Agreements"  means  the  agreements  to  be  entered
into   between   Orbital  and  certain  employees  of   MDA   substantially
in    the   form   attached   as   Exhibit   6.2.5   to   the   Combination
Agreement.

"Combination    Agreement"   means   the   Combination   Agreement    among
Orbital,   Acquisition   and  MDA  dated  as  of   August   31,   1995   as
amended   on   September  29,  1995,  a  copy  of  which  is  appended   as
Appendix "B" hereto.

"Court" means the Supreme Court of British Columbia.

"DGCL"   means   the   General   Corporation   Law   of   the   State    of
Delaware,   including  all  amendments  to  such  statute  from   time   to
time,    and    any    statute   or   regulation   that   supplements    or
supersedes such statute.

"Depositary"   means   Montreal   Trust   Company   of   Canada,   at   its
office set out in the Letter of Transmittal.

"Dissenting   MDA   Shareholders"   means   MDA   Shareholders   who   have
exercised   a   right   of   dissent  in   respect   of   the   Arrangement
Resolution  in  strict  compliance  with  section  190  of  the  CBCA   and
the Interim Order.

"Dissenting   MDA   1988  Optionholders"  means  MDA   1988   Optionholders
who   have   exercised   a   right   of   dissent   in   respect   of   the
Arrangement   Resolution  in  strict  compliance  with   section   190   of
the CBCA and the Interim Order.
"Dividend   Amount"  means  an  amount  equivalent  to  the   full   amount
of   declared  and  unpaid  dividends  on  the  Exchangeable  Shares   plus
all   dividends   declared  on  Orbital  Common  Shares   that   have   not
been   declared  on  the  Exchangeable  Shares  in  accordance   with   the
Exchangeable Share Provisions.

"Effective   Date"  means  the  date  on  which  the  Arrangement   becomes
effective   as  established  by  the  date  of  issue  of  the  certificate
of   amendment  in  respect  of  the  Plan  of  Arrangement  to  be  issued
by   the  Director  under  the  CBCA  pursuant  to  subsection  192(7)   of
the CBCA.

"Effective   Time"   means   12:01   a.m.   (Vancouver   time)    on    the
Effective Date.

"Employment   Agreements"   means   the   employment   agreements   to   be
entered   into   between   MDA  and  certain  officers   substantially   in
the form attached as Exhibit 3.18 to the Combination Agreement.

"Exchange   Ratio"   is   equal  to  US$5.41   divided   by   the   Average
Closing   Price,  provided  that  in  no  event  shall  it  be  less   than
0.2705 or greater than 0.3607.

"Exchange  Right"  means  the  right of  the  Trustee,  on  behalf  of  the
holders    of   Exchangeable   Shares   other   than   Orbital   and    its
Affiliates,    to   require   Orbital   to   purchase   the    Exchangeable
Shares   upon   the  occurrence  of  certain  events  as  stated   in   the
Voting and Exchange Trust Agreement.

"Exchangeable    Share   Provisions"   means   the   rights,    privileges,
restrictions   and   conditions  attaching  to  the  Exchangeable   Shares,
which are set forth in Appendix A to the Plan of Arrangement.

"Exchangeable   Shares"  means  the  Exchangeable  Non-Voting   Shares   of
Acquisition    having    the   rights,   privileges,    restrictions    and
conditions set forth in the Exchangeable Share Provisions.

"Final   Order"   means  the  final  order  of  the  Court  approving   the
Arrangement.

"Holding   Company  Agreements"  means  the  agreements   to   be   entered
into   among   Acquisition,   the   respective   Qualifying   Holdcos   and
their   shareholders,  substantially  in  the  form  attached  as   Exhibit
2.1.2 to the Combination Agreement.

"Insolvency    Event"   means   the   dissolution    or    winding-up    of
Acquisition,   any   insolvency   or   bankruptcy   proceeding   instituted
by   or   against   Acquisition,  including  any  such   proceeding   under
the    Companies'    Creditor   Arrangement   Act    (Canada)    and    the
Bankruptcy   and  Insolvency  Act  (Canada),  the  admission   in   writing
by   Acquisition   of  its  inability  to  pay  its  debts   generally   as
they  become  due  and  the  inability  of  Acquisition,  as  a  result  of
solvency   requirements   of   the  CBCA,  to   redeem   any   Exchangeable
Shares tendered for retraction.

"Interim  Order"  means  the  interim  order  of  the  Court,  a  copy   of
which is appended to this Proxy Circular as Appendix "D".

"Letter   of  Transmittal"  means  the  letter  of  transmittal   for   use
by  MDA  Shareholders.   A  copy  is  enclosed  with  this  Proxy  Circular
and    additional    copies   are   available   on   request    from    the
Depositary.

"Liquidation   Call   Right"  means  the  overriding  right   of   Orbital,
in   the   event   of   and   notwithstanding  the  proposed   liquidation,
dissolution,   winding-up  or  insolvency  of  Acquisition,   to   purchase
from   all   but   not  less  than  all  of  the  holders  of  Exchangeable
Shares  all  but  not  less  than  all  of  the  Exchangeable  Shares  held
by   each  such  holder,  as  more  particularly  described  in  the   Plan
of Arrangement.

"MDA"    means    MacDonald,    Dettwiler   and    Associates    Ltd.,    a
corporation   existing   under  the  CBCA,  and  where   the   context   so
requires, means MDA and its subsidiaries.

"MDA Board" means the board of directors of MDA.

"MDA  Common  Shares"  means  the  common  shares  of  MDA,  together  with
all Rights.

"MDA   Options"   means   collectively,  the  options   outstanding   under
the  MDA  1988  Option  Plans,  the  Key Employee  Share  Option  Plan  and
the Amended and Restated Key Employee Share Option Plan.

"MDA   1988   Option  Plans"  means  together,  the  1988  Employee   Share
Option  Plan  of  MDA  and  the  1988 Key Employee  Share  Option  Plan  of
MDA.

"MDA 1988 Optionholder" means a holder of an MDA 1988 Option.

"MDA   1988   Options"   means  the  options   to   purchase   MDA   Common
Shares issued under the MDA 1988 Option Plans.

"MDA Shareholder" means a holder of record of MDA Common Shares.

"NASDAQ"   means   the   National   Association   of   Securities   Dealers
Automated Quotation National Market System.

"Nesbitt   Burns"   means  Nesbitt  Burns  Inc.,   financial   advisor   to
MDA.

"Orbital"    means    Orbital   Sciences   Corporation,    a    corporation
existing  under  the  laws  of  the  State  of  Delaware,  and  where   the
context so requires, means Orbital and its subsidiaries.

"Orbital   Common  Shares"  means  the  common  stock,   par   value   $.01
per share, of Orbital.

"Plan   of   Arrangement"   means   the  plan   of   arrangement   proposed
under  section  192  of  the  CBCA,  substantially  in  the  form  attached
to   this  Proxy  Circular  as  Appendix  "A,"  as  amended,  modified   or
supplemented from time to time in accordance with its terms.

"Proxy    Circular"    means   this   Management    Information    Circular
including   the   Annexes   and  Appendices   attached   hereto   and   all
amendments and supplements hereto from time to time.

"PSC" means The PSC Communications Group, a division of MDA.

"Qualifying  Holdco"  means  a  corporation  that  shall  have   become   a
party  to  the  Plan  of  Arrangement prior to  the  date  of  the  Special
Meeting   pursuant   to  the  Plan  of  Arrangement   and   in   accordance
with   the   terms   of   the   Combination  Agreement   and   shall   have
satisfied   all  the  conditions  under  its  respective  Holding   Company
Agreement    to   the   satisfaction   of   Acquisition   in    its    sole
discretion.

"Redemption  Call  Right"  means  the  overriding  right  of  Orbital,   in
the    event   of   and   notwithstanding   a   proposed   redemption    of
Exchangeable  Shares  by  Acquisition,  to  purchase  from  all   but   not
less  than  all  of  the  holders  of  Exchangeable  Shares  all  but   not
less   than   all   of   the  Exchangeable  Shares  held   by   each   such
holder,    as    more   particularly   described    in    the    Plan    of
Arrangement.

"Replacement   Option"   means  an  option  to  purchase   Orbital   Common
Shares issued or granted in replacement of a MDA Option.

"Retraction  Call  Right"  means  the  overriding  right  of  Orbital,   in
the   event   of   and   notwithstanding  a  request   by   a   holder   of
Exchangeable  Shares  for  Acquisition  to  redeem  any  or  all   of   the
Exchangeable   Shares  registered  in  the  name   of   such   holder,   to
purchase   all   but   not  less  than  all  of  the  Exchangeable   Shares
that   are  the  subject  of  such  request  directly  from  such   holder,
as more particularly described in the Plan of Arrangement.

"Rights"   means   all  rights  associated  with  the  Common   Shares   in
the   capital   of   MDA,   including   without   limitation   all   rights
associated   with   such  Common  Shares  pursuant   to   the   Shareholder
Protection Rights Plan.

"SEC" means the United States Securities and Exchange Commission.

"SFAS"     means    the    Financial    Accounting    Standards     Board's
statements of financial accounting standards.

"Shareholder    Protection    Rights   Plan"    means    the    Shareholder
Protection   Rights   Plan  Agreement  dated  as   of   August   27,   1992
between   MDA   and   Montreal  Trust  Company   of   Canada,   as   Rights
Agent, as amended from time to time.

"Special   Meeting"  means  the  meeting  of  MDA  Shareholders   and   MDA
1988   Optionholders  to  be  held  on  Tuesday,  November  14,   1995   to
consider   the   Arrangement  Resolution  and  to  transact  such   further
and   other  business  as  may  properly  come  before  the  meeting,   and
any adjournment thereof.

"Special  Voting  Share"  means  the  one  Series  A  Preferred  Share   of
Orbital  to  be  issued  to  the  Trustee by  Orbital  in  connection  with
the   Arrangement  and  to  be  held  by  the  Trustee  pursuant   to   the
terms of the Voting and Exchange Trust Agreement.

"Support   Agreement"   means   the   agreement   to   be   entered    into
between    Acquisition    and    Orbital    in    connection    with    the
Arrangement  substantially  in  the  form  attached  as  Exhibit   2.3   to
the Combination Agreement.

"TSE" means The Toronto Stock Exchange.

"Trustee" means State Street Bank and Trust Company.

"U.S.   dollars"  and  "US$"  mean  the  lawful  currency  of  the   United
States.

"U.S.   GAAP"  means  generally  accepted  accounting  principles  in   the
United States.

"Voting   Agreements   and   Irrevocable  Proxy"   means   the   agreements
between   certain  directors,  officers  and  shareholders   of   MDA   and
Orbital   relating   to  the  voting  by  such  persons   of   MDA   Common
Shares held by them on the Arrangement Resolution.

"VSE" means the Vancouver Stock Exchange.

"Voting   and  Exchange  Trust  Agreement"  means  the  agreement   to   be
entered    into    as    of   the   Effective   Date    between    Orbital,
Acquisition   and   the   Trustee  in  connection  with   the   Arrangement
substantially   in   the   form   attached   as   Exhibit   2.2   to    the
Combination Agreement.

"Voting   Rights"  means  the  voting  rights  attached  to   the   Special
Voting   Share  exercisable  by  the  Trustee  at  the  direction  of   the
holders   of   Exchangeable  Shares  pursuant   to   the   terms   of   the
Voting and Exchange Trust Agreement.


              MDA AND ORBITAL REPORTING CURRENCIES
                    AND ACCOUNTING PRINCIPLES

The   financial  information  related  to  MDA  contained  in  this   Proxy
Circular  is  reported  in  Canadian  dollars  and  has  been  prepared  in
accordance   with   Canadian  GAAP,  which  differs  in  certain   respects
from U.S. GAAP.

The   financial   information  related  to  Orbital,  including   the   pro
forma   financial  information,  contained  in  this  Proxy   Circular   is
reported  in  U.S.  dollars  and  has  been  prepared  in  accordance  with
U.S.   GAAP,  which  differs  in  certain  respects  from  Canadian   GAAP.
See   Notes   2   and  G  to  the  pro  forma  financial   information   of
Orbital   for   an   explanation   of  the   relevant   major   differences
between U.S. GAAP and Canadian GAAP.


                  CANADIAN/U.S. EXCHANGE RATES

In   this   Proxy  Circular,  dollar  amounts  are  expressed   either   in
"Canadian  dollars,"  "Cdn$,"  "$"  or  "dollars"  or  in  "U.S.   dollars"
or "US$."

According   to   Reuters   Historical   Data   for   calendar    1992    to
calendar   1994  and  for  the  nine  months  ended  September  30,   1995,
the  high  and  low  exchange  rates  (i.e.  the  rate  at  which  Canadian
dollars   were   sold  for  U.S.  dollars),  the  average   exchange   rate
(i.e.  the  average  of  the  exchange  rates  on  the  last  day  of  each
month  during  the  period)  and  the  end-of-period  exchange  rates   for
one   Canadian   dollar  expressed  in  U.S.  dollars   for   the   periods
indicated are set forth below:



                     Twelve          Nine Months Ended
                     Months              September 30,
                     Ended
                        
                    December
                      31,
                    _______     _________________________
                       1992     1993     1994        1995
                      US$       US$      US$         US$
                                       
High for period      0.8485   0.7994   0.7567      0.7446
Low for period       0.7725   0.7417   0.7097      0.7009
End of period        0.7866   0.7566   0.7133      0.7410
Average for          0.8249   0.7737   0.7302      0.7288
period



On  September  29,  1995, the noon buying rate for  Cdn$1.00  was
US$0.7442.
                   SUMMARY OF PROXY CIRCULAR

The  following  is  a  summary of certain information  about  the
Arrangement, MDA, Orbital and Acquisition and is qualified in its
entirety  by  reference to the full text of this Proxy  Circular,
including  the  annexes and appendices hereto.  MDA  Shareholders
and MDA 1988 Optionholders are urged to read this Proxy Circular,
including  the  accompanying  annexes  and  appendices,  in   its
entirety.  See "Risk Factors" for certain information that should
be  considered  by  MDA Shareholders and MDA 1988  Optionholders.
For the definitions of certain terms used in this Proxy Circular,
see "Glossary of Terms."

General

Orbital Sciences Corporation, MacDonald, Dettwiler and Associates
Ltd.  and  3173623  Canada  Inc., a newly  formed  subsidiary  of
Orbital,  have entered into the Combination Agreement.   Pursuant
to  the  Combination Agreement, MDA and Acquisition have  applied
for  and  received  the  Interim Order of the  Supreme  Court  of
British  Columbia calling the Special Meeting of MDA Shareholders
and  MDA  1988  Optionholders to consider  the  approval  of  the
Arrangement under section 192 of the CBCA.

Pursuant  to  the  Arrangement, MDA will become  a  wholly  owned
subsidiary  of Acquisition and each outstanding MDA Common  Share
will  be  exchanged  for  a  number  of  Exchangeable  Shares  of
Acquisition equal to the Exchange Ratio.  The Exchange Ratio will
be determined by dividing US$5.41 by the average closing price of
Orbital Common Shares for the 20 trading days ending on the  date
four trading days prior to the Effective Date of the Arrangement,
provided that the Exchange Ratio will not be less than 0.2705  or
greater  than  0.3607.   Outstanding  MDA  Options  will   become
Replacement  Options to acquire Orbital Common  Shares  on  terms
identical   to   the  existing  MDA  Options,  with   appropriate
adjustments  in  the  exercise price and  the  number  of  shares
subject  to  such  options to reflect the  Exchange  Ratio.   The
Exchangeable  Shares will have voting, dividend  and  liquidation
rights  that are, as nearly as practicable, equivalent  to  those
rights of the Orbital Common Shares.

Orbital is a space technology company that designs, manufactures,
operates and markets a broad range of space products and services
that  include launch systems, space and electronics systems,  and
communications and information systems.  Orbital had revenues  of
approximately  US$222  million for the year  ended  December  31,
1994.   As  of June 30, 1995, Orbital's total backlog,  including
firm  orders  of approximately US$495 million, was  approximately
US$1.3  billion.   The closing sales price of an  Orbital  Common
Share on September 29, 1995 was US$16.25, as reported by NASDAQ.

The Arrangement and The Combination Agreement

The Combination Agreement, a copy of which is appended hereto  as
Appendix  "B," provides for the implementation of the Arrangement
under  the  CBCA, including obtaining the Interim Order,  calling
the  Special Meeting and obtaining the Final Order of  the  Court
approving  the  Arrangement.   The  Combination  Agreement   also
contains  the  terms  and  conditions  of  Orbital's,  MDA's  and
Acquisition's obligations to consummate the Arrangement.

The  Arrangement.   Pursuant  to the Arrangement,  (i)  MDA  will
become  a  wholly owned subsidiary of Acquisition and an indirect
subsidiary  of Orbital, (ii) MDA Shareholders (except  dissenting
holders,  and  except corporations ("Qualifying  Holdcos")  that,
together with their respective shareholders, have entered into an
agreement   (a  "Holding  Company  Agreement")  with  Acquisition
substantially  in  the  form attached as  Exhibit  2.1.2  to  the
Combination  Agreement  and have met  the  conditions  under  the
Holding  Company Agreement) will receive, in exchange  for  their
MDA  Common Shares, a number of Exchangeable Shares equal to  the
product of the number of such MDA Common Shares multiplied by the
Exchange  Ratio; (iii) all outstanding shares of each  Qualifying
Holdco  will  be  exchanged for a number of  Exchangeable  Shares
equal to the product of the number of MDA Common Shares owned  by
such  Qualifying  Holdco multiplied by the  Exchange  Ratio;  and
(iii)  each  outstanding  MDA Option will  be  converted  into  a
Replacement  Option exercisable for a number  of  Orbital  Common
Shares  equal  to the product of the number of MDA Common  Shares
subject  to such MDA Option multiplied by the Exchange Ratio,  at
an exercise price per share equal to the exercise price per share
of  such MDA Option divided by the Exchange Ratio, and subject to
the  same vesting, expiration and other terms as such MDA Option.
In  addition,  Acquisition will issue 10,000  Class  B  Preferred
Shares  to Canadian Imperial Bank of Commerce as partial  payment
for  investment  banking services rendered with  respect  to  the
Arrangement.  See "The Arrangement and the Combination  Agreement
- - Plan of Arrangement."

Recommendation and Fairness Opinion.  The MDA Board has  approved
the  Combination  Agreement and unanimously recommends  that  MDA
Shareholders  and  MDA  1988  Optionholders  vote  to  adopt  the
Arrangement Resolution.  Nesbitt Burns Inc., financial advisor to
MDA, has delivered to the MDA Board its written opinion dated  as
of  October  4, 1995 (a copy of which is attached to  this  Proxy
Circular  as  Appendix "C") to the effect that,  based  upon  and
subject  to the various considerations set forth in such  opinion
and  as of that date, the Arrangement is fair to MDA Shareholders
and  MDA 1988 Optionholders from a financial point of view.   The
fees to be paid to Nesbitt Burns are contingent upon consummation
of  the  Arrangement.  See "The Arrangement and  the  Combination
Agreement - MDA's Reasons for the Arrangement and Recommendations
of the MDA Board" and "- Opinion of MDA's Financial Advisor."

Qualifying Holdcos.  The Combination Agreement provides that  any
MDA  Shareholder that wishes to contribute its MDA Common  Shares
to  a  holding company and exchange the shares of the  Qualifying
Holdco  for  Exchangeable  Shares as  provided  in  the  Plan  of
Arrangement   may  do  so  by  complying  with   certain   notice
provisions,  entering  into  a  Holding  Company  Agreement   and
satisfying  the  conditions  set forth  in  the  Holding  Company
Agreement.  See "The Arrangement and the Combination Agreement  -
Qualifying Holdcos."

Description of Exchangeable Shares.  The Exchangeable Shares will
have  voting, dividend and liquidation rights that are, as nearly
as  practicable, equivalent to those rights of the Orbital Common
Shares, and will be exchangeable for Orbital Common Shares  on  a
one-for-one  basis  (subject to adjustment).   Each  Exchangeable
Share  will  be  entitled to receive dividends  from  Acquisition
payable  at the same time as, and to the extent possible  in  the
same  property or cash as, and in the case of cash dividends,  in
the  Canadian dollar equivalent of, each dividend paid by Orbital
on  an  Orbital Common Share.  The Exchangeable Shares  generally
will    not   be  entitled  to  vote  on  matters  submitted   to
Acquisition's  shareholders  but,  pursuant  to  the  Voting  and
Exchange Trust Agreement, holders of Exchangeable Shares will  be
provided with voting rights that will entitle them to vote  along
with  holders  of Orbital Common Shares on matters  submitted  to
Orbital's   shareholders.   In  the  event  of  the  liquidation,
dissolution or winding-up of Acquisition or Orbital, a holder  of
Exchangeable  Shares will receive one Orbital  Common  Share  for
each  Exchangeable  Share  (subject to adjustment).   Acquisition
will   automatically   redeem  all   Exchangeable   Shares   then
outstanding on the fifth anniversary of the Effective  Date,  and
may  redeem all outstanding Exchangeable Shares at any time  when
there are less than 400,000 outstanding Exchangeable Shares  held
by  persons other than Orbital and its Affiliates, in  each  case
for   a  redemption  price  of  one  Orbital  Common  Share   per
Exchangeable  Share  (subject to adjustment).   Upon  a  proposed
retraction  or  redemption of an Exchangeable Share,  or  in  the
event   of   the   liquidation,  dissolution  or  winding-up   of
Acquisition, Orbital will have the right, in lieu of  Acquisition
making  such  retraction, redemption or liquidation  payment,  to
purchase  Exchangeable Shares for a price of one  Orbital  Common
Share  for  each Exchangeable Share (subject to adjustment).   In
the  event  of  certain capital or corporate  reorganizations  of
Orbital,  the number of Orbital Common Shares to be  issued  upon
the   exchange  of  Exchangeable  Shares  will  be  appropriately
adjusted  so  that  the  holders of the Exchangeable  Shares  are
treated  in the same manner as holders of Orbital Common  Shares.
Although   the  transfer  of  Exchangeable  Shares,  subject   to
receiving certain orders from securities regulators, will not  be
restricted  under applicable securities laws, except  in  certain
stated  instances, the Exchangeable Shares will not be listed  on
any  stock  exchange and MDA does not expect there  will  be  any
market for the Exchangeable Shares.  See "The Arrangement and the
Combination Agreement - Description of Exchangeable Shares."

Voting  and  Exchange  Trust Agreement.  At the  Effective  Time,
Acquisition, Orbital and the Trustee will enter into  the  Voting
and Exchange Trust Agreement pursuant to which Orbital will issue
to  the  Trustee  one Series A Preferred Share  of  Orbital  (the
"Special Voting Share").  The Special Voting Share will vote with
the Orbital Common Shares at any meeting at which the holders  of
Orbital  Common Shares are entitled to vote, and will be entitled
to a number of votes equal to the number of Orbital Common Shares
issuable  upon  exchange of all Exchangeable  Shares  outstanding
from  time  to  time not owned by Orbital or its Affiliates.   On
each  vote  of  Orbital  Common Shares, holders  of  Exchangeable
Shares as of the record date established for the meeting at which
such vote will be taken will have the right to direct the Trustee
with  respect to a number of votes equal to the number of Orbital
Common  Shares  issuable  upon  exchange  of  their  Exchangeable
Shares.   See  "The Arrangement and the Combination  Agreement  -
Description of Exchangeable Shares - Voting Rights."

Pursuant to the Voting and Exchange Trust Agreement, Orbital will
grant  to  the  Trustee  for  the  benefit  of  the  holders   of
Exchangeable  Shares  the Exchange Right,  exercisable  upon  the
liquidation,  dissolution  or insolvency  of  Acquisition  or  if
Acquisition  defaults in its dividend, retraction  or  redemption
obligations with respect to the Exchangeable Shares,  to  require
Orbital to purchase all or any part of the Exchangeable Shares at
a   purchase  price  of  one  Orbital  Common  Share   for   each
Exchangeable Share (subject to adjustment).  In addition, Orbital
will  grant to the Trustee for the benefit of the holders of  the
Exchangeable  Shares  the Automatic Exchange  Right,  exercisable
upon  the  liquidation, dissolution or winding-up of Orbital,  to
automatically  exchange each Exchangeable Share for  one  Orbital
Common Share (subject to adjustment) five business days prior  to
the date of any such liquidation event.  See "The Arrangement and
the Combination Agreement - Description of Exchangeable Shares  -
Retraction, Redemption and Exchange Right."

Support  Agreement.   At  the  Effective  Time,  Acquisition  and
Orbital  will enter into the Support Agreement pursuant to  which
Orbital  will  covenant to take such action as  is  necessary  to
permit   Acquisition  to  (i)  pay  simultaneous  and  equivalent
dividends  on the Exchangeable Shares as are paid by  Orbital  on
the  Orbital  Common Shares, and (ii) honour the  redemption  and
retraction  rights  and  the dissolution  entitlements  that  are
attributes  of  the  Exchangeable Shares.  The Support  Agreement
will also provide that, without the prior approval of the holders
of  the  Exchangeable  Shares,  Orbital  will  not  take  certain
actions, such as declaring dividends on the Orbital Common Shares
or  effecting reclassifications or reorganizations of the Orbital
Common  Shares,  without  the same or an economically  equivalent
action  being taken in respect of the Exchangeable  Shares.   See
"The   Arrangement  and  the  Combination  Agreement  -   Support
Agreement."

Court   Approval   and  Completion  of  the   Arrangement.    The
implementation of the Arrangement is subject to the  Final  Order
approving  the Arrangement.  MDA, Acquisition and Orbital  intend
to apply for the Final Order as promptly as practicable after the
Special  Meeting.   A copy of the Notice of Application  for  the
Final  Order is attached as Appendix "E" hereto.  The hearing  in
respect  of  the  Final  Order  is scheduled  to  take  place  on
November  16,  1995  before  the presiding  Judge  or  Master  in
Chambers at the Courthouse, 800 Smithe Street, Vancouver, British
Columbia.   At  that hearing, any MDA Shareholder, any  MDA  1988
Optionholder  and  any  other  interested  party  who  wishes  to
participate  or  to  be  represented or to  present  evidence  or
argument may do so, subject to filing with the Court and  serving
appropriate  notices of appearance in accordance with the Interim
Order.   At  the  hearing  for the Final Order,  the  Court  will
consider,  among  other factors, the fairness of the  Arrangement
and   the   approval  of  the  Arrangement  Resolution   by   MDA
Shareholders and MDA 1988 Optionholders.  The Effective  Date  of
the  Arrangement will occur after the Final Order is obtained and
all  other  conditions  in the Combination  Agreement  have  been
satisfied  or  waived, which is expected to occur promptly  after
the  Special  Meeting.  See "The Arrangement and the  Combination
Agreement - Court Approval and Completion of the Arrangement."

Conditions  to the Arrangement.  Consummation of the  Arrangement
is  subject  to  the  satisfaction of  a  number  of  conditions,
including  but not limited to: (i) the passage of the Arrangement
Resolution   by   the  MDA  Shareholders   and   the   MDA   1988
Optionholders;  (ii) Dissenting MDA Shareholders  and  Dissenting
MDA 1988 Optionholders being entitled in the aggregate to receive
no more than 10% of the aggregate number of Orbital Common Shares
and  Replacement Options to be issued pursuant  to  the  Plan  of
Arrangement;   (iii)   the  receipt  of   necessary   orders   or
registrations under applicable securities regulations  to  permit
the  transactions contemplated by the Arrangement to be completed
and  the  Exchangeable Shares to be freely  tradeable  except  in
certain   limited  circumstances;  (iv)  the   absence   of   any
restrictive court orders or any other legal restraints preventing
or  making illegal the consummation of the Arrangement;  (v)  the
continuing   accuracy   in   all   material   respects   of   the
representations  and  warranties  made  by  each   of   MDA   and
Acquisition and Orbital in the Combination Agreement on and as of
the Effective Date; and (vi) the receipt by Orbital of an opinion
that  the  Arrangement is to be accounted for  as  a  pooling  of
interests.  See "The Arrangement and the Combination Agreement  -
The Combination Agreement."

Termination.  The Combination Agreement may be terminated and the
Arrangement  may  be  abandoned  prior  to  the  Effective  Date,
notwithstanding the approval by the MDA Shareholders and the  MDA
1988  Optionholders  of  the Arrangement  Resolution,  under  the
circumstances specified in the Combination Agreement,  including:
(i)  by  Orbital,  if  the Average Closing  Price  is  more  than
US$25.00;  (ii) by Orbital, if the MDA Board shall have withdrawn
or  modified in any manner adverse to Orbital its support of  the
Arrangement,  or  shall  fail to affirm  such  support  upon  the
request of Orbital; (iii) by MDA, if the Average Closing Price is
less  than  US$12.775; (iv) by MDA, if MDA receives a  bona  fide
offer  to  acquire  all  the  shares  or  assets  of  MDA  for  a
consideration  per  MDA Common Share having a fair  market  value
greater than US$5.95, based on prevailing exchange rates  at  the
date  of  the offer; (v) by mutual agreement of Orbital and  MDA;
and (vi) by either party if the Arrangement is not consummated by
December  31,  1995 (other than as a result of a default  of  the
terminating  party).   Under certain  circumstances  MDA  may  be
required  to  pay  Orbital a US$750,000 termination  fee  if  the
Combination  Agreement is terminated by MDA. See "The Arrangement
and  the  Combination  Agreement - The  Combination  Agreement  -
Termination  and  Amendment"  and "-  Solicitation  of  Alternate
Transactions."

Operations Following the Arrangement.  Orbital currently  expects
that following the Arrangement, MDA will continue to operate as a
separate  entity,  substantially in the same  manner  as  it  has
operated  its  business  prior  to  the  Arrangement.   See  "The
Arrangement and the Combination Agreement - Operations  Following
the Arrangement."

Accounting  Treatment.   The  Arrangement  is  expected   to   be
accounted for as a pooling of interests under U.S. GAAP,  and  it
is   a  condition  to  Orbital's  obligation  to  consummate  the
Arrangement that Orbital shall have received an opinion  of  KPMG
Peat  Marwick LLP, its independent auditors, to the  effect  that
such  accounting treatment is appropriate.  See "The  Arrangement
and the Combination Agreement - Accounting Treatment."

Certain Canadian Federal Income Tax Considerations

The   following  discussion  of  Canadian  federal   income   tax
considerations  is  intended as a general summary  and  does  not
discuss  all of the facts and circumstances that may  affect  the
tax  liability of particular holders of MDA Common Shares and MDA
1988  Options.  Holders of MDA Common Shares and MDA 1988 Options
are  urged  to consult their own tax advisors.  See  "Income  Tax
Considerations to MDA Shareholders and Optionholders  -  Canadian
Federal Income Tax Considerations."

Residents of Canada.  A holder of MDA Common Shares who  receives
Exchangeable  Shares  will generally not be subject  to  Canadian
income  tax in respect of such transaction (i) if such holder  is
not considered to receive Voting Rights or the Exchange Right for
MDA  Common Shares, or (ii) even if such holder is considered  to
receive  Voting  Rights  or the Exchange  Right  for  MDA  Common
Shares, if such holder effects a Tax Election under section 85 of
the  Canadian  Tax Act specifying a transfer price equal  to  the
aggregate  of  the adjusted cost bases of such MDA Common  Shares
immediately before the exchange.

Pursuant to the Canadian Tax Act, a holder of an outstanding  MDA
1988 Option that becomes a Replacement Option will be deemed  not
to  have disposed of the MDA 1988 Option and not to have acquired
the  Replacement  Option, provided the value of  the  Replacement
Option  is  not  greater than the value of the MDA  1988  Option.
Furthermore,  for  purposes  of  the  tax  consequences  of   the
Replacement Option, the Replacement Option will be deemed  to  be
the  same  option as, and a continuation of, the MDA 1988  Option
and  Orbital will be deemed to be the same corporation as, and  a
continuation of, MDA.

So  long as the value of the Call Rights, Exchange Right and  the
Voting Rights is nominal, the grant of Call Rights by a holder of
Exchangeable Shares, in consideration of the receipt of  Exchange
Right  and  Voting  Rights, should not  result  in  any  material
Canadian federal income tax consequences.

A  holder  of  Exchangeable Shares who  receives  Orbital  Common
Shares  from Acquisition on a redemption (including a retraction)
by Acquisition of the holder's Exchangeable Shares will be deemed
to  receive a dividend as a result of such redemption.  A  holder
of Exchangeable Shares who exchanges his Exchangeable Shares with
Orbital  for Orbital Common Shares upon the exercise of the  Call
Rights  or  the Exchange Right will generally realize  a  capital
gain (or capital loss) as a result of such exchange.

Non-Residents  of  Canada.  Provided the MDA  Common  Shares  are
listed   on   a  prescribed  stock  exchange  at  the   time   of
implementation of the Arrangement, a holder of MDA Common  Shares
who  is  not resident in Canada, who holds MDA Common  Shares  as
capital  property  and  does  not  hold  MDA  Common  Shares   in
connection  with a business carried on in Canada, generally  will
not  be  subject to tax under the Canadian Tax Act  solely  as  a
result of the transactions effected pursuant to the Arrangement.

A non-resident holder of Exchangeable Shares who receives Orbital
Common  Shares  from  Acquisition on a  redemption  (including  a
retraction) of the holder's Exchangeable Shares will be deemed to
receive  a dividend as a result of such redemption that  will  be
subject  to  non-resident withholding tax under the Canadian  Tax
Act at the rate of 25%, subject to reduction under the provisions
of  an  applicable  income tax treaty.  Under  the  Canada-United
States  Income Tax Convention, the rate is generally  reduced  to
15% for residents of the United States.  A holder of Exchangeable
Shares  who  exchanges his Exchangeable Shares with  Orbital  for
Orbital Common Shares upon the exercise of the Call Rights or the
Exchange Right will generally realize a capital gain (or  capital
loss) as a result of such exchange.

An exchange of Exchangeable Shares for Orbital Common Shares by a
non-resident may be subject to tax under the Canadian Tax Act.  A
non-resident may be exempt from tax pursuant to the provisions of
an  applicable tax treaty such as the Canada-United States Income
Tax Convention.  In any case, Orbital or Acquisition will require
non-residents to obtain a certificate from Revenue Canada on such
exchange  specifying a certificate limit not less than  the  fair
market   value  of  the  Orbital  Common  Shares.   If  no   such
certificate is obtained, then either Orbital or Acquisition  will
withhold and remit to Revenue Canada as tax on behalf of such non-
resident  holder, 33J% of the fair market value  of  the  Orbital
Common Shares, and Orbital or Acquisition will deliver to the non-
resident  holder  a reduced number of Orbital  Common  Shares  to
reflect such payment to Revenue Canada.

Certain United States Federal Income Tax Considerations

The  following  discussion of United States  federal  income  tax
considerations  is  intended as a general summary  and  does  not
discuss  all of the facts and circumstances that may  affect  the
tax  liability of particular MDA Shareholders.  MDA  Shareholders
are  urged  to consult their own tax advisors.  See  "Income  Tax
Considerations  to  MDA Shareholders and Optionholders  -  United
States Federal Income Tax Considerations."

U.S.  Shareholders.  MDA and Orbital believe, based on advice  of
counsel,  that there is a reasonable basis on which  to  conclude
that   the  exchange  of  MDA  Common  Shares  pursuant  to   the
Arrangement  will  constitute  a  taxable  transaction  for  U.S.
federal  income  tax purposes, and MDA understands  that  Orbital
intends  to report the exchange in a manner consistent  with  the
foregoing.  If the exchange is taxable, MDA Shareholders who  are
"United  States  persons" for U.S. federal  income  tax  purposes
("U.S.  Holders"), including United States citizens or residents,
domestic  corporations,  domestic partnerships,  and  estates  or
trusts  subject  to  U.S.  federal income  tax  on  their  income
regardless  of  source,  who  receive Exchangeable  Shares  would
recognize  capital  gain  or  loss in  an  amount  equal  to  the
difference  between  the fair market value  of  the  Exchangeable
Shares   received  (together  with  cash  received  in  lieu   of
fractional  shares (if any)) and the tax basis of the MDA  Common
Shares  surrendered in the exchange.  Such capital gain  or  loss
would  generally constitute U.S. source gain and would  be  long-
term capital gain or loss if the MDA Common Shares exchanged have
been held for more than one year at the time of the exchange.  It
is  possible,  however, that the United States  Internal  Revenue
Service  (the  "IRS") may take the position that the  receipt  of
Exchangeable Shares in exchange for MDA Common Shares  is  not  a
taxable  event, in which case a U.S. Holder would  only  have  to
recognize gain to the extent of cash in lieu of fractional shares
(if  any),  and  certain carryover tax basis and  holding  period
rules would apply to the Exchangeable Shares.

MDA  and  Orbital also believe, based on the advice  of  counsel,
that  there is a reasonable basis on which to conclude  that  the
exchange, retraction or redemption of the Exchangeable Shares for
Orbital Common Shares will be treated as a taxable event for U.S.
federal income tax purposes, and Orbital has advised MDA that  it
currently  intends to take this position.  If the exchange  is  a
taxable event, a U.S. Holder that receives Orbital Common  Shares
from   Orbital  pursuant  to  the  Call  Rights  would  generally
recognize  capital  gain or loss equal to the difference  between
the fair market value of the Orbital Common Shares at the time of
the exchange (together with cash in lieu of fractional shares (if
any) and cash equal to the Dividend Amount (if any)) and the  tax
basis  of  the  Exchangeable Shares.  Such capital gain  or  loss
would  be  long-term  capital gain or loss  if  the  Exchangeable
Shares  have been held for more than one year at the time of  the
exchange.   It  is possible, however, that the IRS  could  assert
that  a  portion  of such gain constitutes U.S.  source  ordinary
income.   If  the  receipt of Orbital Common Shares  is  effected
through  a  retraction  or  redemption  of  Exchangeable   Shares
distributed to a U.S. Holder directly by Acquisition, then if the
retraction or redemption is treated as a taxable transaction,  it
would be treated as a taxable exchange of the Exchangeable Shares
if  the U.S. Holder meets certain tests relating to reductions in
its  percentage shareholdings in Acquisition, and otherwise would
be  taxed  as a dividend paid on the Exchangeable Shares  to  the
extent  of  Acquisition's (or, possibly, Orbital's) earnings  and
profits.  It is possible, however, that the IRS could assert that
the exchange, retraction or redemption of Exchangeable Shares for
Orbital  Common Shares is not a taxable event, in  which  case  a
U.S.  Holder would only have to recognize gain to the  extent  of
cash  in  lieu  of  fractional shares (if any) and  the  Dividend
Amount  (if  any),  and certain carryover tax basis  and  holding
period rules would apply to the Orbital Common Shares.

Non-U.S. Shareholders.  A holder of MDA Common Shares that is not
a  U.S.  Holder ("non-U.S. Holder") generally will not be subject
to U.S. federal income tax on a gain recognized on the receipt of
the Exchangeable Shares, Voting Rights and Exchange Right, or  on
the  subsequent  sale or exchange of the Exchangeable  Shares  or
Orbital  Common Shares, unless such gain is effectively connected
with a U.S. trade or business.

Dividends  received  by a non-U.S. Holder  with  respect  to  the
Orbital   Common  Shares  generally  will  be  subject  to   U.S.
withholding  tax at a rate of 30%, which rate may be  subject  to
reduction  by  an applicable income tax treaty in effect  between
the  U.S. and the non-U.S. Holder's country of residence.   Under
the  Canada-U.S.  Income Tax Convention, the  rate  is  generally
reduced  to 15%.  Although the matter is not entirely  free  from
doubt,  dividends received by a non-U.S. Holder  on  Exchangeable
Shares should not be subject to U.S. withholding tax.

The Special Meeting

Time  and  Place.  The Special Meeting will be held  on  Tuesday,
November 14, 1995 at the office of MDA at 13800 Commerce Parkway,
Richmond, B.C., V6V 2J3, at 10:00 a.m. (Vancouver time).

MDA Shareholders and MDA 1988 Optionholders Entitled to Vote.  At
the Special Meeting, the MDA Shareholders (voting together as one
class) and the MDA 1988 Optionholders (voting separately from the
MDA  Shareholders as a second class) will each consider and  vote
upon  a proposal to approve the Arrangement Resolution, and  will
transact  such  other business as may properly  come  before  the
Special  Meeting  or  any adjournments  thereof.   The  close  of
business on October 10, 1995 is the record date for determination
of  MDA Shareholders entitled to receive notice of and to vote at
the Special Meeting, subject to the rights of certain transferees
of MDA Common Shares after that date in accordance with the CBCA.
All  holders  of  MDA  1988 Options on the date  of  the  Special
Meeting  will  be  entitled to attend and  vote  at  the  Special
Meeting.  As of September 29, 1995, 11,218,156 MDA Common  Shares
and  277,643 MDA 1988 Options were outstanding.  See "The Special
Meeting -General Proxy Information."

Vote  Required.  Subject to any further order of the  Court,  the
Arrangement  Resolution must be approved by the affirmative  vote
of   66K%  of  the  votes  actually  cast  thereon  by  the   MDA
Shareholders and the MDA 1988 Optionholders, voting  as  separate
classes (and for this purpose any spoiled votes, illegible votes,
defective  votes and abstentions shall be considered  not  to  be
votes cast).  Directors, officers and shareholders of MDA holding
approximately  56.6%  of  the issued and outstanding  MDA  Common
Shares  have  executed Voting Agreements and Irrevocable  Proxies
with  Orbital agreeing to vote for the Arrangement Resolution  at
the Special Meeting.  In addition, certain officers and employees
of  MDA holding approximately 59.2% of total votes entitled to be
cast  by the MDA 1988 Optionholders have agreed with MDA to vote,
as  MDA 1988 Optionholders, for the Arrangement Resolution.   See
"The Special Meeting - General Proxy Information - Required Votes
to  Approve  the  Arrangement and Voting  Intentions  of  Certain
Shareholders and Optionholders."

Dissent Rights.  MDA Shareholders and MDA 1988 Optionholders  who
do  not vote in favour the Arrangement Resolution and comply with
certain procedures are entitled to dissent under section  190  of
the  CBCA, in accordance with the Interim Order.  See "Dissenting
Rights."

Business of Orbital

Orbital is a space technology company that designs, manufactures,
operates and markets a broad range of space products and services
that are grouped into three categories: Launch Systems, Space and
Electronics Systems, and Communications and Information  Systems.
Launch  Systems  include  space and suborbital  launch  vehicles;
Space  and  Electronics  Systems include  satellites,  spacecraft
platforms, space sensors and instruments, and space payloads  and
experiments,  as  well as advanced avionics and  data  management
systems;  and  Communications  and  Information  Systems  include
satellite-based  two-way  mobile  data  communications   systems,
satellite-based  navigation products and remote sensing  systems,
along   with   satellite  tracking  systems   and   environmental
monitoring products.  See "Information Concerning Orbital."

Orbital's  goal  is  to become a full-service  space  company  by
integrating  its launch vehicles, satellites and  other  products
into  complete "turn-key" space systems and providing  end-to-end
satellite-based  services  for  particular  markets.    Orbital's
strategy  is  to  exploit  expanding  opportunities  to   provide
government,  commercial and other customers with low-cost  access
to  space.   Essential  elements of  Orbital's  strategy  include
investment  of substantial private capital in the development  of
proprietary products; reduction of the time required for  product
development; formation of strategic business alliances to enhance
Orbital's   marketing,  technical,  manufacturing  and  financial
capabilities;    establishment    of    vertically     integrated
manufacturing  and  testing  capabilities;  and  acquisitions  of
companies with product lines that complement or enhance Orbital's
existing  base  of products, services and technologies.   Orbital
believes  that  providing  lower-cost  "turn-key"  space  systems
should  stimulate  the  use  of space products  and  services  by
private  corporations, educational and research institutions  and
other  non-traditional  space  customers  including,  ultimately,
individual consumers.

Orbital's   customer  base  includes  a  wide   range   of   U.S.
governmental  agencies,  universities and commercial  enterprises
including: the U.S. National Aeronautics and Space Administration
("NASA");  the  National Oceanic and Atmospheric  Administration;
various  organizations  within the  U.S.  Department  of  Defense
("DoD"),  including the U.S. Army, the U.S. Navy,  the  U.S.  Air
Force,  the  Advanced Research Projects Agency ("ARPA")  and  the
Ballistic Missile Defense Organization ("BMDO"); ORBCOMM  Global,
L.P.  ("ORBCOMM Global"), an affiliate of Orbital; Johns  Hopkins
University;   and   certain  distributors  of   electronics   and
recreational equipment.

Launch   Systems.    Orbital's  Launch   Systems   Group's   most
significant products are space and suborbital launch vehicles.  A
space  launch vehicle launches a satellite into orbit around  the
Earth.   Suborbital launch vehicles place payloads into a variety
of  high-altitude trajectories but, unlike space launch vehicles,
do not place payloads into Earth orbit.

Orbital's space launch vehicles are the Pegasusr launch  vehicle;
the  Pegasus XL launch vehicle (a modified, larger version of the
Pegasus);  and  the  Taurusr launch  vehicle.   The  Pegasus  and
Pegasus  XL  vehicles are launched from beneath a modified  large
aircraft  such as a Lockheed L-1011 to deploy satellites weighing
up  to  1,000  pounds into low-Earth orbit.  The  higher-capacity
Taurus  vehicle  is a ground-launched derivative of  the  Pegasus
vehicle  that can carry payloads weighing up to 3,000  pounds  to
low-Earth  orbit  and  payloads weighing  up  to  800  pounds  to
geosynchronous  orbit.   In  March  1995,  Orbital  and  Rockwell
International  Corporation agreed to  form  a  joint  venture  to
develop,  construct, operate and market a new advanced technology
small reusable space launch vehicle (the "X-34").

Orbital's  suborbital launch products include  various  types  of
suborbital  vehicles  and  their principal  subsystems,  payloads
carried   by   such   vehicles,  and   related   launch   support
installations  and systems used in their assembly and  operation.
Customers  typically use Orbital's suborbital launch vehicles  to
launch  scientific  and  other payloads and  for  defence-related
applications such as target and interceptor experiments for anti-
missile defence systems.

Space  and  Electronics Systems.  Orbital's Space and Electronics
Systems Group's products include spacecraft systems and payloads,
defence avionics and sensors.

The  Space and Electronics Systems Group is responsible  for  the
design,  production  and  testing  of  small  and  medium   class
spacecraft  for scientific, military and commercial applications.
The  small  standard spacecraft platforms developed  by  Orbital,
such  as  the  PegaStarO and the MicroStarO, are designed  to  be
launched  by  the Pegasus, Pegasus XL or Taurus launch  vehicles.
The  PegaStar spacecraft platform is a general purpose spacecraft
that has successfully performed on one mission, and is planned to
be  used  for  Orbital's SeaStarO ocean environmental  monitoring
satellite  system.   Orbital's MicroStar spacecraft  platform  is
designed  for  use in the ORBCOMM Global satellite-based  two-way
data  communications network consisting of  up  to  36  MicroStar
satellites (the "ORBCOMM System") and also for a variety of small
space  science  and  remote sensing projects, including  some  of
those being pursued by Orbital's wholly owned subsidiary, Orbital
Imaging   Corporation  ("ORBIMAGE").   Orbital's   medium   class
satellites are generally used to gather various scientific  data,
such  as  ocean  topography and ultraviolet sources  outside  the
galaxy.

Orbital  develops,  manufactures and markets  avionics  products,
including  advanced electronics and data management  systems  for
aircraft  flight  operations  and ground  support  for  the  U.S.
military  and  foreign  governments.  The Space  and  Electronics
Systems Group also is responsible for the design, production  and
testing of spacecraft command and data handling, attitude control
and  structural  subsystems  for  a  variety  of  government  and
commercial customers.  Other Space and Electronics Systems  Group
products   include   satellite-borne   scientific   sensors   and
instruments, such as atmospheric ozone monitoring instruments and
environmental sensors.

Communications and Information Systems.  Orbital's Communications
and  Information  Systems Group includes Orbital's  subsidiaries:
Orbital  Communications  Corporation  ("ORBCOMM"),  ORBIMAGE  and
Magellan Corporation ("Magellan").

In  June  1993, ORBCOMM and Teleglobe Mobile Partners ("Teleglobe
Mobile"),  a  partnership formed by Teleglobe Inc. ("Teleglobe"),
formed  ORBCOMM Global to design, develop, construct,  integrate,
test  and  market the ORBCOMM System.  The ORBCOMM  System  is  a
satellite-based  communications  network  designed   to   provide
virtually  continuous  mobile data communications  coverage  over
much  of the Earth's surface.  The ORBCOMM System will include  a
constellation  of  up  to  36  small  low-Earth  orbit  MicroStar
satellites,  a satellite control centre operating and positioning
the  satellites, network control centres controlling the flow  of
information through the system, local ground stations sending and
receiving signals between the network control centres and  nearby
satellites,  and the mobile communicators used by subscribers  to
transmit and receive messages to and from nearby satellites.   In
April  1995,  Orbital launched on a Pegasus  launch  vehicle  the
first  two  satellites  of the ORBCOMM  System.   ORBCOMM  Global
expects  to  begin  intermittent commercial service  using  these
satellites during the first quarter of 1996.

ORBIMAGE is currently seeking to develop and market a broad range
of   information  services  that  identify  and  monitor   global
environmental  changes and collect and disseminate  other  remote
sensing  information.  Small Earth-viewing satellites and related
sensors and instruments to be placed in relatively low orbits are
expected  to  offer cost-efficient data collection, daily  global
coverage  and high-resolution sensing services.  Services  to  be
provided  by  ORBIMAGE  could  include  high-resolution   optical
imaging  of land surfaces for geographic information and  sensing
of ozone and atmospheric conditions.

Magellan  designs,  manufactures and markets  Global  Positioning
System  satellite-based navigation and positioning  products  for
commercial  and  consumer markets including marine  and  aviation
applications,  outdoor recreational users  such  as  hunters  and
hikers,  professional  users  such  as  geologists,  geographers,
surveyors, natural resource managers and contractors  and,  to  a
lesser extent, governmental users.

Business of MDA

MDA  provides  technology-based solutions and services  to  Earth
information,  air  navigation,  defence  applications  and   data
communications markets worldwide, through four business areas.

Geo-Information Systems.  Geo-Information Systems, MDA's  largest
business  area,  involves  the development  of  systems  for  the
management  of Earth resources and the environment,  by  applying
MDA's  expertise in Earth observation ground stations and related
markets.   MDA  is  one  of  the  world's  leading  companies  in
providing  solutions  for the acquisition, processing,  archiving
and  dissemination of non-classified Earth observation data.   Of
the 26 non-secret ground stations in the world,  MDA has built or
been  part  of  the  construction of 23  ground  stations  in  20
countries.   In addition to pursuing opportunities to  build  new
ground  stations,  MDA  is  actively  pursuing  opportunities  to
upgrade existing ground stations so that they are able to process
the  data  that  new  technologically-advanced Earth  observation
satellites are able to provide.

In  addition  to  systems for space-based Earth observation,  MDA
builds systems to process Earth images from airborne radar.   MDA
also   designs  and  builds  customized  software   products   in
consultation  with consumers in government and industry  to  make
geographic related data more useful.  The Geo-Information Systems
business  area provides operational and post-delivery support  to
ensure  operational  efficiency  of  systems  delivered  to   its
customers.  This support includes consulting services,  training,
maintenance and test equipment, spare parts and manuals.

Aviation  Systems.   MDA's  Aviation  Systems  business  area  is
focused on specific markets, including the provision of automated
aeronautical  information  systems  and  automated  air   traffic
management  systems.   MDA builds and markets  the  Pegasus-AISTM
(unrelated  to  Orbital's  Pegasus  space  launch  vehicle),   an
automated  aeronautical  information  management  system.    This
system  provides  pilots and other users  with  aeronautical  and
meteorological  information.  In addition, MDA  is  developing  a
niche  in  the embedding of its aeronautical information  systems
into broader air traffic management systems.

MDA is currently participating in the development and delivery of
air  traffic  management  software to be  used  in  the  Canadian
Automated  Air  Traffic System.  Air traffic  management  systems
allow  air  traffic  controllers to guide  pilots  in  flight  by
combining    information   about   flights,   routes,    weather,
navigational aids, airways and airports, and delivering it to air
traffic  controllers in a form that is intended to enable timely,
safe decisions.

Space  and  Defence  Systems.  MDA's Space  and  Defence  Systems
business  area provides surveillance and command support  systems
for  space and defence.  MDA's defence systems include naval mine
countermeasures, artillery command and control,  radar  deception
systems and military materiel management.  In space-related work,
MDA  continues to provide major software development  efforts  as
part of Canada's contribution to the Space Station project.  This
activity  provides  an opportunity for the enhancement  of  MDA's
space-qualified software capabilities.

Communications.   In  1994, MDA entered a  new  computer  network
communications  consulting  and  training  business  through  the
acquisition  of  Ottawa-based The PSC Communications  Group  Inc.
PSC  helps  customers  design  and  implement  networks  so  that
computers can communicate faster and at lower cost, and  develops
software  for special client needs, such as to monitor  networks,
and   find   and   correct  trouble-spots.    PSC   also   offers
instructional classes for a variety of vendor products,  as  well
as  general courses in computer communications, aimed  mainly  at
technicians in companies across North America, Europe  and  other
parts of the world.
              MARKET PRICE AND DIVIDEND INFORMATION

Orbital  Common  Shares  are quoted on NASDAQ  under  the  symbol
"ORBI".   The following table sets forth the high and low closing
sale  prices reported on NASDAQ for an Orbital Common  Share  for
the  periods  indicated.  The closing sale price  of  an  Orbital
Common Share on the NASDAQ on July 28, 1995, the last trading day
prior  to  the  public  announcement  of  the  Arrangement,   was
US$17.625  and  on  September 29, 1995,  the  latest  practicable
trading  day  before  the printing of this  Proxy  Circular,  was
US$16.25.

Twelve Month Periods          High       Low
Ended December 31,             US$       US$

1993
First Quarter                   14.25      10.75
Second Quarter                  13.75      10.25
Third Quarter                   19.00      12.25
Fourth Quarter                  23.00      16.50

1994                                            
First Quarter                   26.50      15.25
Second Quarter                  24.50      14.00
Third Quarter                   18.50      14.50
Fourth Quarter                  22.50      15.00

1995                                            
First Quarter                   20.50      16.50
Second Quarter                  22.00      15.50
Third Quarter                   19.25      16.25

MDA  Common  Shares have been traded on the VSE since  August  9,
1993  and on the TSE since April 3, 1995 under the symbol  "MDA".
The  following  table sets forth the high and  low  closing  sale
prices  reported on the VSE and TSE for an MDA Common  Share  for
the  periods indicated.  The closing sale price for an MDA Common
Share on the TSE on July 28, 1995, the last trading day prior  to
the  public announcement of the Arrangement, was Cdn$5.50 and  on
September 29, 1995, the latest practicable trading day before the
printing   of  this  Proxy  Circular,  was  Cdn$6.375.   Assuming
Effective  Dates  of July 28, 1995 and September  29,  1995,  the
Exchange Ratio would have been .2927 and .3133, respectively.


                                    VSE              TSE

Twelve Month Periods Ended       High    Low    High     Low
December 31,                     
                                 Cdn$     Cdn$    Cdn$    Cdn$
                                            

1993                                                    
August 9 to Sept. 30              4.50    3.80   ---     ---

Fourth Quarter                    4.10    3.00   ---     ---

1994                                                     ---

First Quarter                     4.15    3.20   ---

Second Quarter                    4.00    3.50   ---     ---

Third Quarter                     4.25    3.65   ---     ---

Fourth Quarter                    4.00    3.25   ---     ---

1995

First Quarter                     3.75    2.90   ---     ---

Second Quarter                    3.75    3.50  4.55(1)  3.30 (1)

Third Quarter                     6.625   6.625  7.125   4.05



Note 1: Commencing April 3, 1995.


Neither  Orbital nor MDA has paid any dividends on  their  common
shares  except for a cash dividend of $1.00 per MDA Common  Share
paid  by  MDA  in  1992.   Orbital currently  intends  to  retain
earnings  for use in its business and does not anticipate  paying
cash  dividends  on the Orbital Common Shares in the  foreseeable
future.   In  addition, Orbital is subject to certain contractual
restrictions  on  its ability to pay dividends.  The  Combination
Agreement prohibits the payment of any dividends by MDA prior  to
the Effective Date.

         SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA

The  following selected historical financial information  of  MDA
and  Orbital  has  been derived from their respective  historical
consolidated  financial  statements,  and  should  be   read   in
conjunction with such consolidated financial statements  and  the
related  notes  thereto,  which are attached  as  Annex  "I"  for
Orbital and Annex "II" for MDA to this Proxy Circular.

Selected Historical Consolidated Financial Data of MDA

The  following selected consolidated financial data as of and for
the  fiscal years ended March 31, 1993, 1994 and 1995 of MDA  are
derived  from  the  consolidated  financial  statements  of  MDA,
including  those contained in Annex "II" to this Proxy  Circular,
and   should  be  read  in  conjunction  with  such  consolidated
financial   statements  and  the  related  notes  thereto.    The
following  selected  consolidated financial data  for  the  three
months  ended June 30, 1994 and 1995 and as of June 30, 1995  are
derived  from  the  unaudited consolidated  financial  statements
included in Annex "II" to this Proxy Circular.  In the opinion of
management  of  MDA,  the unaudited consolidated  financial  data
reflect all adjustments, consisting of normal recurring accruals,
necessary  for  a fair presentation.  The operating  results  for
interim  periods are not necessarily indicative  of  the  results
expected for the full year.

Omitted:  See the Consolidated Financial Data of MDA included
in Item 7(a) above.

Selected Historical Consolidated Financial Data of Orbital

The  following selected consolidated financial data as of and for
the  years ended December 31, 1992, 1993 and 1994 of Orbital  are
derived  from  consolidated  financial  statements  contained  in
Annex  "I"  to  this  Proxy  Circular,  and  should  be  read  in
conjunction with such consolidated financial statements  and  the
related  notes  thereto.   The  following  selected  consolidated
financial  data for the six months ended June 30, 1994  and  1995
and  as  of  June  30, 1995 are derived from unaudited  condensed
consolidated financial statements included in Annex "I"  to  this
Proxy  Circular.   In the opinion of management of  Orbital,  the
unaudited  consolidated financial data reflect  all  adjustments,
consisting  of normal recurring accruals, necessary  for  a  fair
presentation.  The operating results for interim periods are  not
necessarily indicative of the results expected for the full year.

Omitted:  See the Selected Historical Consolidated Financial Data
of Orbital included in the Company's Annual Report on Form 10-K
filed with the SEC on March 29, 1995.

                PRO FORMA FINANCIAL INFORMATION

For purposes of the following pro forma presentation, Orbital has
assumed  that  the conversion of the Exchangeable  Shares  occurs
contemporaneously with the other transactions  occurring  on  the
Effective  Date (i.e., that Orbital issues Orbital Common  Shares
directly  for MDA Common Shares).  The actual number  of  Orbital
Common  Shares issuable pursuant to the Combination Agreement  is
based  on the Average Closing Price.  Assuming an Average Closing
Price  of US$17.25 per Orbital Common Share and an Exchange Ratio
of  .3136 Orbital Common Shares to 1.00 MDA Common Share, Orbital
expects to issue approximately 3.9 million Orbital Common  Shares
for  all  issued and outstanding MDA Common Shares and under  all
Replacement  Options  for MDA Options.  The Arrangement  will  be
accounted for using the pooling of interests method of accounting
and,  accordingly, MDA's assets and liabilities will  be  carried
forward at their historical recorded amounts.

The   following   unaudited  pro  forma  condensed   consolidated
financial  information  consists  of  the  Unaudited  Pro   Forma
Condensed  Consolidated  Statements of  Operations  for  the  six
months  ended  June 30, 1995 and for the year ended December  31,
1994,  and the Unaudited Pro Forma Condensed Consolidated Balance
Sheet   as  of  June  30,  1995  (collectively,  the  "Pro  Forma
Statements").   The  Unaudited Pro Forma  Condensed  Consolidated
Statement  of Operations for the six months ended June  30,  1995
gives  effect  to  the  Arrangement as  if  it  had  occurred  on
January  1, 1995.  The Unaudited Pro Forma Condensed Consolidated
Statement  of  Operations for the year ended  December  31,  1994
gives  effect  to  the  Arrangement as  if  it  had  occurred  on
January  1, 1994.  The Unaudited Pro Forma Condensed Consolidated
Balance  Sheet  gives  effect to the Arrangement  as  if  it  had
occurred  on June 30, 1995.  The Pro Forma Statements  have  been
prepared in accordance with U.S. GAAP (see Notes 2 and G  to  the
Pro  Forma  Statements  for a description  of  major  differences
between U.S. GAAP and Canadian GAAP).

Orbital's  management  believes that,  on  the  basis  set  forth
herein, the Pro Forma Statements reflect a reasonable estimate of
the  Arrangement based on currently available information and the
assumptions  described herein.  The pro forma financial  data  do
not  purport  to represent what Orbital's financial  position  or
results   of  operations  would  actually  have  been   had   the
Arrangement in fact occurred on June 30, 1995, January 1, 1995 or
January  1,  1994, or to project Orbital's financial position  or
results  of  operations for any future date or period  indicated.
The  Pro Forma Statements should be read in conjunction with  the
consolidated financial statements of each of Orbital and MDA  and
related   notes  thereto  included  in  Annexes  "I"  and   "II,"
respectively.

OMITTED:  See the Unaudited Pro Forma Condensed Cconsolidated Balance
Sheet at June 30, 1995 filed above in Item 7(b).

OMITTED:  See the Unaudited Pro Forma Condensed Consolidated Statement of
Operations for the Six Months Ended June 30, 1995 filed above in Item 7(b).

OMITTED:  See the Unaudited Pro Forma Condensed Consolidated Statement of
Operations for the Year Ended December 31, 1994 filed above in Item 7(b).

OMITTED:  See the Notes to Pro Forma Adjustments to Unaudited Pro Forma
Condensed Consolidated Financial Statements and Notes, Notes to Pro Forma
Adjustments to the Unaudited Pro Forma Condensed Consolidated Financial
Statements and Notes to Conversion Adjustments to the Unaudited Pro
Forma Condensed Consolidated Financial Statements filed above in Item 7(b).

             PRO FORMA CONSOLIDATED CAPITALIZATION

The   following  table  sets  forth  the  short-term   debt   and
capitalization of Orbital, on a pro forma consolidated basis,  to
give effect to the Arrangement.

                                              June 30, 1995
                                               (Pro Forma)
                                                 (US$ in
                                               thousands)
Short-term debt:                                            
    Current portion of long-term                   $   5,639
    obligations                                        7,005
    Short-term bank borrowings                     $  12,644
Total short-term debt

Long-term debt:                                             
    Long-term obligations, net of                     34,927
    current portion                                   20,000
    10 1/2% Senior Notes due 2002                     56,000
    6 3/4% Convertible Subordinated                  $110,927
    Debentures due 2003
Total long-term debt

Stockholders' equity:                                       
    Preferred Shares, par value $0.01                       
    per share: 10,000,000                                  --
     authorized; no shares issued and
    outstanding                                           

    Preferred Series A Shares, par value
    $0.01 per share:                                      --
     one share authorized; no shares                        
    issued and outstanding (1)                              

    Preferred Series B Shares, no par
    value: 10,000 authorized, issued
    and outstanding (2)                                   10

    Preferred Series B Shares, no par                    
    value:                                           
     10,000 authorized, issued and                   
    outstanding (2)                                    

    Common Shares, par value $0.01 per                    266
    share: 40,000,000                               
     authorized; 26,556,640 shares                  
    issued and outstanding
     after adjusting for 15,735 shares
    in treasury (3)

    Additional paid-in capital                        246,243

    Cumulative translation adjustment                  (3,571)

    Unrealized losses on short-term                      (221)
    investments

    Retained earnings (deficit)                        (1,960)

Total stockholders' equity                           $240,767

Total capitalization                                 $351,694


Notes:
(1)  The Preferred Series A Share issued by Orbital is held under
     the Voting and Exchange Trust Agreement and is eliminated in
     consolidation.
(2)  Preferred  Series  B  Shares are issued  by  Acquisition  to
     Canadian   Imperial  Bank  of  Commerce  pursuant   to   the
     Arrangement.
(3)  Assumes   an   immediate   exchange   of   all   outstanding
     Exchangeable Shares and exercise of Replacement Options  for
     3,920,290 Orbital Common Shares.  Excludes 3,900,945 Orbital
     Common  Shares issuable upon conversion of Orbital's 6  3/4%
     Convertible  Subordinated Debentures due 2003 and  1,661,146
     Orbital  Common  Shares reserved for  issuance  pursuant  to
     options  outstanding as of September 8, 1995  with  exercise
     prices ranging from US$7.50 to US$22.00 per share.

                          RISK FACTORS


The   following  risk  factors  related  to  Orbital  should   be
considered  by  MDA  Shareholders and MDA 1988  Optionholders  in
evaluating whether to approve the Arrangement Resolution.   These
factors  should  be  considered in  conjunction  with  the  other
information  included in this Proxy Circular.  In  addition,  MDA
Shareholders  and  MDA 1988 Optionholders should  refer  to  "The
Arrangement - Reasons for Recommendation of the MDA Board."

Technologically Advanced Products and Services

Most  of  the products developed and manufactured by Orbital  are
technologically  advanced and novel systems  that  must  function
under   demanding  operating  conditions.   Even  though  Orbital
believes  it  employs  sophisticated  design,  manufacturing  and
testing  practices,  there  can be no  assurance  that  Orbital's
products  will be successfully launched or operated or that  they
will  be  developed  or  will perform as  intended.   Certain  of
Orbital's  contracts require it to forfeit part of  its  expected
profit,  to  receive reduced payments, to provide  a  replacement
launch  or  other product or service, or to reduce the  price  of
follow-on  missions  if its products fail to perform  adequately.
Performance penalties also may be imposed should Orbital fail  to
meet   delivery   schedules  or  other   measures   of   contract
performance.   Orbital, like most companies and governments  that
have  launch  and satellite programs, has experienced  occasional
product  failures and other problems, including with  respect  to
certain  of  its  launch vehicles and satellites.   For  example,
Orbital's  first  two  flights of the  Pegasus  XL  space  launch
vehicle in June 1994 and June 1995 were unsuccessful.

Orbital's  products  and services are and  will  continue  to  be
subject  to  significant  technological  change  and  innovation.
Orbital's  success  will  generally  depend  on  its  ability  to
penetrate  and  retain markets for its existing products  and  to
continue to conceive, design, develop, manufacture and market new
products  and  services  on a cost-effective  and  timely  basis.
Orbital  anticipates that it will incur significant  expenses  in
the design, development and initial manufacture and marketing  of
new  products  and  services.  There can  be  no  assurance  that
Orbital  will  be  able  to  achieve the  technological  advances
necessary to remain competitive and profitable, that new products
and  services will be developed and manufactured on schedule  and
on a cost-effective basis, that licenses and regulatory approvals
required for new products and services will be secured,  or  that
anticipated  markets will exist or develop for  new  products  or
services.

Dependence on United States Government

A  significant percentage of Orbital's backlog is with  the  U.S.
Government  or under subcontracts with prime contractors  to  the
U.S.  Government.   Most  of Orbital's government  contracts  are
funded  incrementally  on  a  year-to-year  basis.   Changes   in
government policies, priorities or funding levels through  agency
or  program  budget  reductions  by  the  U.S.  Congress  or  the
imposition  of  budgetary constraints could materially  adversely
affect    Orbital's    business   and   financial    performance.
Furthermore, contracts with the U.S. Government may be terminated
or  suspended by the U.S. Government at any time, with or without
cause.

Capital Requirements

Orbital's  future  business requirements and  growth  plans  will
require  significant additional capital.  Orbital  believes  that
working capital, cash from operations, operating leases, customer
financing and available bank borrowings will be adequate to  meet
these  capital needs through 1995.  Orbital expects that it  will
need to incur indebtedness or raise additional equity capital  to
fund  its  anticipated growth in 1996 and beyond.  While  Orbital
believes  that,  if necessary, it has flexibility  to  reduce  or
delay  its  anticipated capital requirements and its  anticipated
investments  in ORBIMAGE or the X-34 program, such reductions  or
delays   could  impede  Orbital's  growth  and  adversely  affect
Orbital's results of operations.

The  ORBCOMM System and the X-34 program are in relatively  early
stages and the actual cost of each project may vary significantly
from  current  estimates.  In addition to the funds committed  by
Orbital  and  its respective partner in each venture,  additional
financing  from the partners and/or third party sources  will  be
required, and there can be no assurance that the required capital
will be received.  In the event that the necessary capital cannot
be  obtained,  implementation and commercial development  of  the
ORBCOMM  System or X-34 will be delayed, significantly restricted
or  possibly abandoned, and Orbital could be required to  expense
part  or all of its investment in the ORBCOMM System or the  X-34
program, as the case may be.

Orbital  has  invested  and will continue to  invest  substantial
resources  in  capital equipment and other assets supporting  its
various  products  and programs.  In the event  of  significantly
reduced  or eliminated product sales with respect to a particular
program, Orbital could be required to expense some or all of  its
investments in assets dedicated to that program.

Regulation

The  ability  of  Orbital  to pursue its business  activities  is
regulated  by  various  agencies  and  departments  of  the  U.S.
Government.  Commercial space launches require licenses from  the
U.S.  Department  of  Transportation  ("DoT")  and  operation  by
Orbital  of  its  leased L-1011 aircraft requires  licenses  from
certain  agencies  of  the DoT, including  the  Federal  Aviation
Administration.  Construction, launch and operation of commercial
communications satellites, including the ORBCOMM System,  require
licenses  from  the  U.S. Federal Communications  Commission  and
frequently  require  the  approval  of  international  regulatory
authorities.   Some  planned  ORBIMAGE  private  remote   sensing
satellites  require  a  license  from  the  U.S.  Department   of
Commerce.   Exports of Orbital's products, services and technical
information frequently require licenses from the U.S.  Department
of  State  or the U.S. Department of Commerce.  There can  be  no
assurance  that  Orbital will continue to be  successful  in  its
efforts to obtain necessary licenses or regulatory approvals.

         THE SPECIAL MEETING - GENERAL PROXY INFORMATION

General

This Proxy Circular is furnished to MDA Shareholders and MDA 1988
Optionholders in connection with the solicitation of  proxies  by
management of MDA to be used at the Special Meeting to be held on
Tuesday, November 14, 1995 at 10:00 a.m., Vancouver time, at  the
offices  of  MDA  at  13800 Commerce Parkway,  Richmond,  British
Columbia,  V6V  2J3,  and  at any adjournments  or  postponements
thereof for the purposes set forth in the accompanying Notice  of
Special Meeting.  The information contained herein is given as at
September 29, 1995, except where otherwise noted.

Solicitation of Proxies

In  addition  to  solicitation by mail, officers,  directors  and
regular  employees  of MDA may, without additional  compensation,
solicit  proxies personally or by telephone or telecopier.   This
solicitation is made on behalf of management of MDA and the  cost
of the solicitation will be borne by MDA.

Arrangements   will  be  made  with  custodians,   nominees   and
fiduciaries  for  forwarding  proxy  solicitation  materials   to
beneficial  owners of MDA Common Shares held of  record  by  such
custodians, nominees and fiduciaries, and MDA will reimburse such
custodians,  nominees  and fiduciaries  for  reasonable  expenses
incurred in connection therewith.

In  order  to be valid for use at the Special Meeting, any  proxy
must be received by Montreal Trust Company of Canada, 510 Burrard
Street,  Vancouver,  British Columbia, V6C  3B9,  not  less  than
48  hours  (excluding Saturdays, Sundays and holidays)  preceding
the Special Meeting or any adjournment thereof.

Appointment of Proxies

The persons named in the enclosed proxy are directors or officers
of MDA.  A MDA Shareholder or MDA 1988 Optionholder who wishes to
appoint  some other person to represent him or her at the Special
Meeting  may do so by inserting such person's name in  the  blank
space provided in the form of proxy or by completing another form
of  proxy and, in either case, delivering it or returning  it  by
mail  so  that  it is received by the stated deadline.   A  proxy
nominee need not be an MDA Shareholder or MDA 1988 Optionholder.

Signing of Proxies

The  proxy  must  be signed by the MDA Shareholder  or  MDA  1988
Optionholder,  as  the case may be, or by  his  or  her  attorney
authorized  in  writing,  as his or her  name  appears  on  MDA's
register  of  shareholders or records  of  holders  of  MDA  1988
Options.  If the MDA Shareholder is a corporation, the proxy must
be executed by a duly authorized officer or attorney thereof.

Revocation of Proxies

In addition to revocation in any other manner permitted by law, a
proxy  given  pursuant to this solicitation  may  be  revoked  by
instrument in writing executed by the MDA Shareholder or MDA 1988
Optionholder,  as  the case may be, or by  his  or  her  attorney
authorized   in  writing  or,  if  the  MDA  Shareholder   is   a
corporation, by a duly authorized officer or attorney thereof and
deposited either:

          (i)  at the registered office of MDA at any time up  to
          and  including the last business day preceding the  day
          of   the  Special  Meeting,  or  any  adjournments   or
          postponements thereof; or

          (ii)  with the chairman of the Special Meeting  on  the
          day  of  the  Special Meeting prior to the commencement
          thereof, or any adjournments or postponements thereof.

Upon either of such deposits, the former proxy will be revoked.

Voting of Proxies

The  persons  named  in the enclosed proxy  will  vote  "FOR"  or
"AGAINST"  the Arrangement Resolution such number  of  shares  or
votes with respect to which such persons are appointed proxy,  on
the  ballot to be cast with respect to the Arrangement Resolution
in accordance with the instructions of the MDA Shareholder or MDA
1988  Optionholder appointing them.  In the absence of  direction
or  instruction,  shares  or  votes  represented  by  a  properly
executed  proxy  will be voted "FOR" approval of the  Arrangement
Resolution.

The  enclosed form of proxy confers discretionary authority  upon
the  persons designated therein with respect to amendments to  or
variations  of matters identified in the accompanying  Notice  of
Special Meeting of Shareholders and with respect to other matters
that  may properly come before the Special Meeting.  At the  date
of  this  Proxy Circular, the management of MDA knows of no  such
amendments,  variations or other matters.  However, if  any  such
amendments,  variations or other matters not presently  known  to
the  management  of MDA should properly come before  the  Special
Meeting,  the shares represented by the proxies will be voted  in
accordance with the best judgment of the person or persons voting
such proxies, absent contrary instructions.

MDA Common Shares

On  September 29, 1995, MDA had outstanding 11,218,156 MDA Common
Shares; the only shares of MDA issued and outstanding.  Each  MDA
Shareholder  of  record at the close of business on  October  10,
1995,  the  record  date established for notice  of  the  Special
Meeting,  will be entitled to one vote for each MDA Common  Share
held  by  him or her on all matters proposed to come  before  the
Special  Meeting,  except  to the  extent  that  he  or  she  has
transferred any MDA Common Shares after the record date  and  the
transferee  of  such  shares  produces  properly  endorsed  share
certificates or otherwise establishes ownership thereof and makes
a  written  demand,  not  later than the  close  of  business  on
November  3,  1995,  to be included in the list  of  shareholders
entitled  to  vote  at the Special Meeting,  in  which  case  the
transferee will be entitled to vote such shares.

MDA 1988 Options

On   September  29,  1995,  MDA  had  277,643  MDA  1988  Options
outstanding.  Each MDA 1988 Optionholder on the date  of  mailing
will  receive  notice of the Special Meeting and  each  MDA  1988
Optionholder,  on  the  date  of the  Special  Meeting,  will  be
entitled  to  one vote for each MDA Common Share such  person  is
entitled to purchase under a MDA 1988 Option.

Required  Votes to Approve the Arrangement and Voting  Intentions
of Certain Shareholders and Optionholders

Subject  to  any  further  order of the  Court,  the  Arrangement
Resolution  must be approved by the affirmative vote of  66K%  of
the  votes actually cast thereon by the MDA Shareholders  and  by
the  MDA 1988 Optionholders, voting as separate classes, and  for
this  purpose any spoiled votes, illegible votes, defective votes
and abstentions shall be considered not to be votes cast.

As at September 29, 1995, the directors and officers of MDA as  a
group  beneficially owned approximately 23.6% of the  outstanding
MDA  Common Shares and executive officers of MDA as a group  held
approximately 47.0% of the outstanding MDA 1988 Options.

All  of  the  directors and officers of MDA and MDA  Shareholders
holding 10% or more of the MDA Common Shares have executed Voting
Agreements  and  Irrevocable Proxies agreeing to hold  their  MDA
Common Shares and to vote for the Arrangement Resolution.   These
agreements  represent  56.6%  of  the  votes  attached   to   the
outstanding  MDA  Common  Shares.   In  addition,  officers   and
employees  of MDA holding approximately 59.2% of the total  votes
entitled  to  be cast by MDA 1988 Optionholders have agreed  with
MDA to hold their options and vote for the Arrangement Resolution
in  their  capacity  as  MDA 1988 Optionholders.   All  of  these
agreements  contain provisions which provide for  termination  in
certain circumstances, including if the Combination Agreement  is
terminated.  See "The Arrangement and the Combination Agreement -
Interests  of  Certain  Persons in the Arrangement"  and  "-  The
Combination Agreement - Termination and Amendment."

Principal Holders of MDA Common Shares and MDA 1988 Options

To  the knowledge of the directors and officers of MDA, the  only
persons who beneficially own, directly or indirectly, or exercise
direction over, MDA Common Shares carrying more than 10%  of  the
votes attached to all of the MDA Common Shares are as follows:




                                        Number of MDA Common
     Name of Shareholder                Shares Beneficially Held         Percentage

                                                                  
     Ventures West Technologies (1)     2,404,104                               21%
     Spar Aerospace Limited             1,292,709                               12%
     John W. Pitts (2)                  1,154,314                               10%
     John S. MacDonald (3)              1,110,449                               10%



Notes:
(1)  Ventures  West  Technologies' holdings are  in  two  limited
     partnerships:   Ventures  West Technologies  (1994)  Limited
     Partnership   owns  1,879,666  shares  and   Ventures   West
     Technologies Limited Partnership owns 524,438 shares.
(2)  Mr.  Pitts  controls 1,154,314 MDA Common Shares  indirectly
     through Anako Holdings Inc.
(3)  Dr.   MacDonald   controls  1,110,449  MDA   Common   Shares
     indirectly through QuMac Enterprises Limited.

There  is no MDA 1988 Optionholder carrying the right to vote  at
the Special Meeting more than 10% of the votes attached to all of
the MDA 1988 Options.

Each   of  the  above  MDA  Shareholders  have  executed   Voting
Agreements  and  Irrevocable Proxies agreeing to hold  their  MDA
Common Shares and to vote for the Arrangement Resolution.

Management of MDA has been advised that Orbital does not own  any
MDA Common Shares.


         THE ARRANGEMENT AND THE COMBINATION AGREEMENT

The Arrangement - General

MDA  Shareholders and MDA 1988 Optionholders are being  asked  to
approve  the  Arrangement under the CBCA whereby:  (i)  MDA  will
become  a  wholly-owned subsidiary of Acquisition and an indirect
subsidiary   of  Orbital;  (ii)  MDA  Shareholders  (other   than
Dissenting  MDA  Shareholders but including  Qualifying  Holdcos)
will  receive, in exchange for all of their MDA Common Shares,  a
number  of  Exchangeable  Shares equal  to  the  product  of  the
Exchange Ratio multiplied by the number of MDA Common Shares held
by  them; and (iii) holders of MDA Options (other than Dissenting
MDA  1988  Optionholders) will receive, in exchange for  each  of
their  MDA  Options,  a  Replacement  Option  entitling  them  to
purchase  a number of Orbital Common Shares equal to the  product
of  the  Exchange Ratio multiplied by the number  of  MDA  Common
Shares  underlying such MDA Option, having an exercise price  per
share  equal to the quotient of the exercise price per  share  of
such  MDA  Option divided by the Exchange Ratio, and  having  the
same vesting, expiration and other terms as such MDA Option.  The
Exchangeable  Shares will have voting, dividend  and  liquidation
rights  that are, as nearly as practicable, equivalent  to  those
rights of the Orbital Common Shares.

Holders  of  Exchangeable Shares will have the right to  exchange
all  or  any  of  such  shares for an equal  number  (subject  to
adjustment  in  the  event  of  certain  capital  and   corporate
reorganizations)  of  Orbital Common  Shares  plus  the  Dividend
Amount  attributable to such shares, at any  time  prior  to  the
Automatic  Redemption Date and subject to certain Call Rights  of
Orbital.  The Exchangeable Shares will be automatically exchanged
on  the  Automatic  Redemption Date and upon  the  occurrence  of
certain events, including the liquidation, dissolution or winding-
up  of Orbital or Acquisition or the default by Acquisition under
the Exchangeable Share Provisions.  Acquisition has the right  to
accelerate  the Automatic Redemption Date upon 75  days'  written
notice  to  the holders of Exchangeable Shares at any  time  when
there are outstanding less than 400,000 Exchangeable Shares  held
by persons other than Orbital and its Affiliates.

Background of the Arrangement

On  March  31,  1995,  the  MDA Board engaged  Nesbitt  Burns  as
financial advisors to MDA to assist in determining whether or not
it  would  be  advantageous  for MDA to  proceed  with  a  public
offering of MDA Common Shares, and to provide advice with respect
to  any  acquisition transaction relating to MDA or  to  the  MDA
Common  Shares.   An engagement letter was executed  by  MDA  and
Nesbitt Burns on June 15, 1995.  At the March 31 meeting the  MDA
Board  proposed  the  terms  of  bonus  arrangements  for  senior
employees in the event of the completion of certain transactions.
See "The Arrangement and the Combination Agreement - Interests of
Certain Persons in the Arrangement."

On  June 8, 1995, at a regularly scheduled board meeting the  MDA
Board  was  advised by a director that Orbital had  indicated  an
interest  in acquiring all of the MDA Common Shares.   Management
was  instructed  by  the  MDA Board  to  meet  with  Orbital  and
determine whether or not a transaction could be proceeded with.

On  June 14, 1995, senior management of MDA and advisors  met  in
Richmond,  B.C.  with senior management of Orbital  to  determine
Orbital's  level  of  interest  and  the  general  terms   of   a
transaction,  including the requirements that the transaction  be
effected  as  a pooling of interests and on a tax deferred  basis
for Canadian MDA Shareholders.

On  June  19,  1995,  the MDA Board met and was  advised  of  the
position  of  Orbital and the general terms of  the  transactions
contemplated.  Management was advised to conduct due diligence on
Orbital  and  if  the  results were  positive,  to  proceed  with
negotiations  with  Orbital  to reach  an  agreement  as  to  the
structure and price of a proposed transaction.

On  June  23,  1995,  Orbital and MDA  signed  a  confidentiality
agreement  and  Orbital  agreed not to purchase  any  MDA  Common
Shares.

During  the period from June 26 to July 12, 1995, executives  and
advisors of Orbital met with representatives of MDA in Vancouver,
B.C. and conducted due diligence on MDA.  Executives and advisors
of MDA met with representatives of Orbital at Orbital's office in
Dulles,   Virginia  and  conducted  due  diligence  on   Orbital.
Discussions  of  a  general nature were held on  the  form  of  a
proposed   transaction,  including  the  requirements  that   the
transaction  be effected on a pooling of interests basis  through
an   arrangement  under  the  CBCA,  and  whereby  Canadian   MDA
Shareholders  would receive a tax deferral as  a  result  of  the
transaction.  In addition, senior management and advisors of  MDA
met   with  senior  management  and  advisors  of  Orbital.   The
preliminary  terms of a proposal were presented  by  Orbital  and
Orbital  and  MDA  commenced  preliminary  negotiations  on   the
exchange  ratio  (price),  conditions  for  completion   of   the
transaction,  factors relating to the exchange ratio,  and  other
related matters.

On  July  13,  1995,  the MDA Board met and was  advised  of  the
results   of   due  diligence  on  Orbital  and  the  preliminary
negotiations.   Representatives  of  Nesbitt  Burns  presented  a
preliminary  review  of the proposed transaction,  including  the
range of prices then being discussed and its preliminary view  as
to  the fairness of a transaction from a financial point of view.
The  MDA  Board  was  advised  of  the  duties  of  directors  in
transactions such as the one being proposed by Orbital.

From  July 17 to July 25, 1995, senior management of MDA and  its
advisors  met  with  senior management  of  Orbital  to  continue
negotiations.   Orbital  and  MDA and  their  advisors  commenced
preparation of the Affiliate Agreements and Voting Agreements and
Irrevocable Proxies.  Drafts of these agreements were  circulated
to  certain shareholders, directors and officers of MDA who would
be required to execute the same.  On July 18, 1995, the MDA Board
met and was advised of the status of negotiations and on July 20,
1995,  MDA  signed a letter with Orbital agreeing not to  solicit
other business combinations except as specified.

On July 27, 1995, the MDA Board met and was updated on the status
of   negotiations  and  the  status  of  the  position  of  major
shareholders   including   Spar   Aerospace   Limited   ("Spar").
Management  was  advised  to  continue  negotiations  and   those
negotiations  were proceeded with.  The meeting  adjourned  until
July  28, 1995 following a meeting between Mr. Wallis of MDA  and
senior  management  of Spar.  At the adjourned  meeting  the  MDA
Board  was  advised of Spar's position and that a  meeting  among
senior  executives  of MDA, Orbital and Spar  would  be  held  on
July  31, 1995.  On July 28, 1995, MDA was advised that Orbital's
board  of  directors  had  given approval  in  principle  to  the
proposed transaction.

On  July 31, 1995, trading in MDA Common Shares was halted on the
TSE  and VSE pending a press release.  MDA, Orbital and Spar  met
to discuss the terms of the proposed transaction and implications
to   Spar.   Spar  senior  management  advised  that  they  would
recommend   supporting  the  transaction  to  Spar's   board   of
directors.   On that date, Orbital and MDA executed a  memorandum
of  understanding with respect to the transaction and each of MDA
and Orbital issued press releases with respect thereto.

On  August  3,  1995, the MDA Board ratified  and  confirmed  the
memorandum  of  understanding,  approved  proceeding   with   the
preparation  of definitive agreements for the completion  of  the
transaction  with  Orbital  and  waived  the  provisions  of  the
Shareholder  Protection Rights Plan to permit  the  execution  of
Voting   Agreements   and  Irrevocable  Proxies   and   Affiliate
Agreements.  Representatives of Nesbitt Burns took part  in  this
meeting  and  gave  an  oral  opinion  on  the  fairness  of  the
Arrangement from a financial point of view.

From  August 5 to August 31, 1995, negotiations were held on  the
form  of  the  definitive  agreements  and  transactions  related
thereto.   On August 17, 1995 the MDA Board met.  Representatives
of  Nesbitt Burns updated the MDA Board with respect to its  view
on  the  fairness of the Arrangement to MDA Shareholders and  MDA
1988  Optionholders and confirmed its opinion on the fairness  of
the  Arrangement.   The MDA Board reviewed and commented  on  the
draft  definitive agreements including the Combination  Agreement
and   discussed  certain  conditions  and  changes  with  respect
thereto.

On   August  17,  1995,  the  MDA  Board  formally  approved  and
authorized execution of the Combination Agreement and waived  the
provisions  of the Shareholder Protection Rights Plan  to  permit
the  transactions contemplated by the Arrangement to be effected.
On  August  18,  1995,  the Orbital board of  directors  met  and
approved the definitive agreements in the form presented, subject
to Orbital's management negotiating the terms of a fee payable by
MDA  in the event MDA were to terminate the Combination Agreement
and  not proceed with the transaction because a higher bona  fide
offer was received by MDA.  Negotiations were conducted over  the
period from August 21 to 22, 1995.  In exchange for the agreement
of  MDA  to  provide  a  break-up fee of  US$750,000  in  certain
circumstances,  the parties agreed that the maximum  and  minimum
range  within which the Exchange Ratio was established be changed
from .3488 to .3607 for the maximum, and from .2578 to .2705  for
the minimum.

From  August  25 to August 31, 1995, the disclosure schedules  of
the  respective parties were reviewed.  On August  31,  1995  the
definitive Combination Agreement was executed, subject to receipt
from Spar of an executed Affiliate Agreement and Voting Agreement
and  Irrevocable Proxy.  These agreements were received from Spar
on September 1, 1995.

On  September 5, 1995, MDA and Orbital issued press releases with
respect  to the execution of the definitive Combination Agreement
and terms of the Arrangement.

As  of  September 29, 1995, the Combination Agreement was amended
and   restated  to  reflect,  inter  alia,  amendments   to   the
Exchangeable Share Provisions as a result of Orbital obtaining  a
"no-action"  letter from the SEC with respect  to  the  issue  of
Orbital Common Shares on the exchange of the Exchangeable Shares.

MDA's Reasons for the Arrangement and Recommendations of the  MDA
Board

On  October  5,  1995  the  MDA Board  unanimously  approved  the
Arrangement and determined that the Arrangement was fair  and  in
the  best interests of MDA, the MDA Shareholders and the MDA 1988
Optionholders.   The  MDA  Board unanimously  recommends  to  MDA
Shareholders and MDA 1988 Optionholders that they vote "FOR"  the
Arrangement Resolution.  The MDA Board based its approval of  the
Arrangement on its determination that the Exchange Ratio is  fair
to  MDA, MDA Shareholders and MDA 1988 Optionholders, and upon  a
number  of  other  factors, including  its  views  regarding  the
following:

          (i)  as of July 28, 1995, the last trading day prior to
          the   public  announcement  of  the  Arrangement,   the
          consideration  provided under the  Arrangement  to  MDA
          Shareholders and MDA 1988 Optionholders of Cdn$7.35 per
          MDA  Common Share (based on currency exchange rates  at
          that date), and provided that the Average Closing Price
          is  US$15.00 or more, represented a 34% premium to  the
          closing  price of MDA Common Shares on the TSE on  that
          date;

          (ii) the Arrangement will provide MDA Shareholders  and
          MDA  1988 Optionholders with the opportunity to receive
          Orbital   Common  Shares,  a  security   that   has   a
          significantly larger market float and greater liquidity
          than MDA Common Shares;

          (iii)                     the opinion of the MDA  Board
          that  the  combination of Orbital's space  and  defence
          business with MDA's expertise in earth imaging and  air
          navigation    systems   will   result    in    expanded
          opportunities  for  MDA's  core  business  that  should
          strengthen overall combined operations;

          (iv)  the  fact  that Orbital's business combined  with
          MDA's   business  after  the  Arrangement   will   have
          significantly greater financial and business  resources
          than  those  of  MDA  alone,  which  may  enable  MDA's
          business  to  compete more effectively with competitors
          having   greater  resources  than  MDA  alone  and   to
          negotiate future acquisitions;

          (v)   the  geographic  distribution  of  customers  for
          Orbital's and MDA's business are complementary and will
          allow  these businesses easier access to new customers;
          and

          (vi)  the  discussions between management  of  MDA  and
          senior executives of Orbital relating to operations  of
          MDA, after the Effective Date.

The  MDA  Board  also  considered the  following  information  in
concluding that the Arrangement and the Exchange Ratio  are  fair
to MDA Shareholders and MDA 1988 Optionholders: (i) its knowledge
of   the   business,  operations,  property,  assets,   financial
condition,  operating results and prospects of MDA  and  Orbital;
(ii)  current industry, economic and market conditions and trends
and  its  informed expectations of the future of the industry  in
which MDA operates; (iii) the opinion of Nesbitt Burns as to  the
fairness from a financial point of view of the Arrangement to MDA
Shareholders and to the MDA 1988 Optionholders; (iv) the terms of
the  Combination Agreement; (v) the structure and accounting  and
tax  treatment  of  the  Arrangement;  and  (vi)  the  respective
corporate cultures and strategies of MDA and Orbital.

In  view of the variety of factors considered in connection  with
its evaluation of the Arrangement, the MDA Board did not find  it
practicable to and did not quantify or otherwise assign  relative
strengths  to  the specific factors considered  in  reaching  its
determination.

Orbital's Reasons for the Arrangement

Orbital  believes that the combination of the two companies  will
expand  the  vertical integration of Orbital's manufacturing  and
testing   capabilities,  enhance  Orbital's  ability   to   offer
customers  complete  space-based systems  and  augment  Orbital's
satellite   tracking  product  line  and  customer   base.    The
combination  of MDA's expertise in satellite ground  systems  and
related information processing software with services offered  by
Orbital  is  expected to achieve synergies that should strengthen
Orbital's ability to offer affordable space-based services, while
also  expanding  the combined company's overall commercial  base.
Orbital  also  anticipates  that MDA's significant  international
presence will solidify Orbital's expansion of its existing  lines
of business into international markets.  Finally, Orbital expects
to  realize synergies due to the ability of the combined  company
to  integrate MDA's technical expertise in such areas as advanced
space-qualified  software,  air navigation  systems  and  defence
electronics   with  Orbital's  existing  defence   and   avionics
products.

Operations Following the Arrangement

Following the Arrangement, Orbital expects that MDA will continue
to operate as a separate entity, substantially in the same manner
as it is operated prior to the Effective Date.

Interests of Certain Persons in the Arrangement

In  considering the recommendation of the MDA Board with  respect
to  the  Arrangement, MDA Shareholders and MDA 1988 Optionholders
should  be aware that certain officers and directors of  MDA  had
interests in the Arrangement, including those referred to  below,
that  may present potential conflicts of interest.  The MDA Board
was  aware of these potential conflicts and considered them along
with  the  other  matters described in "The Arrangement  -  MDA's
Reasons  for  the  Arrangement and  Recommendations  of  the  MDA
Board."

Dr.  John S. MacDonald, Chairman of MDA will be asked to join the
board  of  directors  of  Orbital. On  the  Effective  Date,  Dr.
MacDonald will execute an Employment Agreement with MDA.

The  President and each area general manager of MDA will  execute
an  Employment Agreement with MDA which will provide for  payment
of  compensation in accordance with industry standards  and  will
contain an obligation on the employee not to compete with MDA for
a  two  year period following the  Effective Date.  The Chairman,
the  President  and  each general manager will also  concurrently
enter  into a Change of Control Agreement with Orbital that  will
provide  compensation to them of two times their annual level  of
compensation  if  their  employment with  MDA  is  terminated  or
changed in certain circumstances following a change of control of
Orbital or MDA after the Effective Date.

The  MDA Board, in March, 1995, approved the grant of a bonus  to
certain  members  of  MDA  management in  the  event  of  certain
transactions  such as share dispositions and sales of  assets  of
MDA  occurring, to compensate for the fact that change of control
agreements  were  not in place for these members  of  management.
The  amount  of  the  bonus  will  based  on  the  value  of  the
transaction,  including the price for MDA Common Shares  obtained
thereunder.  If a transaction were completed at a price no higher
than the price for MDA Common Shares at the time of the grant  no
bonus  would  have been payable under the formula therefor.   The
aggregate  amount of this bonus will be allocated  among  certain
members   of  MDA's  management,  including  officers,   by   the
compensation  committee  of  the MDA  Board  and  while  not  yet
definitively allocated, the amount paid to any one recipient  may
be significant to that recipient.

Opinion of MDA's Financial Advisor

MDA  appointed  Nesbitt Burns on March 31, 1995  to  act  as  the
exclusive  financial advisor to MDA and to evaluate the  fairness
from  a financial point of view to MDA Shareholders and MDA  1988
Optionholders  of  certain business transactions,  including  the
Arrangement.  An engagement letter was executed on June 15,  1995
relating  to this appointment.  Nesbitt Burns was retained  based
on  its  experience  as a financial advisor  in  connection  with
mergers  and acquisitions and in securities valuation as well  as
Nesbitt Burns' familiarity with relevant markets and with MDA.

As compensation for its financial advisory services in connection
with  a  proposed business combination Arrangement MDA agreed  to
pay   Nesbitt  Burns  a  success  fee  on  the  closing  of   any
transaction.   Assuming  the Average  Closing  Price  is  between
US$15.00   and  US$20.00,  this  fee  is  estimated  to   be   to
Cdn$981,000.   Whether or not a transaction is  consummated,  MDA
has  agreed  to  reimburse Nesbitt Burns  for  its  out-of-pocket
expenses,  including reasonable counsel fees,  and  to  indemnify
Nesbitt  Burns  against  certain  liabilities  and  expenses   in
connection  with  its  services  as  financial  advisor  to  MDA,
including liabilities arising under securities laws.

Nesbitt  Burns first delivered to the MDA Board its oral  opinion
on  fairness of the Arrangement at the MDA Board meeting held  on
August   3,  1995.   Concurrently  with  the  execution  of   the
Combination Agreement on August 31, 1995, Nesbitt Burns delivered
to  the MDA Board a written opinion that the Arrangement was fair
to  the  MDA Shareholders and the MDA 1988 Optionholders  from  a
financial  point of view.  This opinion was subsequently  updated
to  October 4, 1995.  The complete text of Nesbitt Burns' opinion
is attached hereto as Appendix "C" and the summary of the opinion
set forth below is qualified in its entirety by reference to such
opinion.   MDA Shareholders and MDA 1988 Optionholders are  urged
to  read  such  opinion  carefully and  in  its  entirety  for  a
description  of  the procedures followed, the factors  considered
and  the  assumptions made by Nesbitt Burns.  In connection  with
the rendering of its opinion dated October 4, 1995, Nesbitt Burns
among other things reviewed and relied upon:

(a)  the  most  recent  available draft of  this  Proxy  Circular
     prepared in connection with the Arrangement;

(b)  the Combination Agreement as at September 29, 1995;

(c)  the Voting Agreements and Irrevocable Proxies;

(d)  the  agreement dated as of July 31, 1995 between Orbital and
     MDA  outlining  the  proposed terms and  conditions  of  the
     Arrangement;

(e)  the  Agreement dated July 20, 1995 between Orbital  and  MDA
     relating to MDA's agreement not to solicit third party  bids
     ("No-Shop Agreement");

(f)  audited  financial statements of MDA for each of the  fiscal
     years  in the five-year period ended March 31, 1995 and  the
     unaudited  financial statements of MDA for the  three  month
     periods ended June 30, 1994 and June 30, 1995;

(g)  the  budget  for  MDA for the fiscal year ending  March  31,
     1996;

(h)  the strategic plan for MDA dated April 24, 1995 for the five
     fiscal   years  ending  March  31,  2000  prepared  by   the
     management of MDA;

(i)  certain income tax information with respect to MDA;

(j)  publicly  available  information related  to  the  business,
     operations  and  consolidated financial performance  of  MDA
     including  the annual report to shareholders for the  fiscal
     year ended March 31, 1995;

(k)  confidential  information provided to Nesbitt Burns  by  the
     management of MDA consistent with that disclosed to Orbital;

(l)  discussions  with senior management of MDA with  respect  to
     the  information referred to in (f), (g), (h), (i)  and  (j)
     above,  and  MDA management's assessment of the current  and
     prospective  operations of MDA and the industries  in  which
     they operate;

(m)  relevant stock market information relating to the MDA Common
     Shares  and  the shares of other companies whose  activities
     include businesses similar to certain of MDA's businesses;

(n)  data  with  respect to other transactions  of  a  comparable
     nature considered by Nesbitt Burns to be relevant;

(o)  such  other  financial, market and industry information  and
     such other analysis as Nesbitt Burns considered relevant and
     appropriate in the circumstances; and

(p)  a  certificate  dated  the date of the opinion  from  senior
     officers  of  MDA  as  to the accuracy and  completeness  of
     certain information provided to Nesbitt Burns.

In addition, Nesbitt Burns reviewed and relied upon the following
with respect to Orbital:

(a)  audited  financial statements of Orbital  for  each  of  the
     fiscal years in the five-year period ended December 31, 1994
     and  the  unaudited financial statements for the six  months
     ended June 30, 1994 and June 30, 1995;

(b)  publicly  available  information related  to  the  business,
     operations   and   consolidated  financial  performance   of
     Orbital, including the annual report to shareholders for the
     fiscal year ended December 31, 1994;

(c)  confidential  information provided to Nesbitt Burns  by  the
     management of Orbital consistent with that disclosed to MDA;

(d)  discussions  with senior management of Orbital with  respect
     to the information referred to in (a), (b) and (c) above and
     Orbital   management's  assessment  of   the   current   and
     prospective  operations of Orbital, and  the  industries  in
     which it operates;

(e)  relevant  stock market information relating to  the  Orbital
     Common  Shares  and  the  shares of  other  companies  whose
     activities   include  businesses  similar  to   certain   of
     Orbital's businesses;

(f)  data  with respect to transactions involving other companies
     similar to Orbital; and

(g)  such  other  financial, market and industry information  and
     such other analysis as Nesbitt Burns considered relevant and
     appropriate in the circumstances.

Nesbitt  Burns' conclusion as to the fairness of the  Arrangement
from  a  financial point of view to the MDA Shareholders and  MDA
1988   Optionholders   was  based  upon   various   factors   and
assumptions, including without limitation, the following:

(a)  the  conclusion that fairness in respect of the  Arrangement
     for  MDA  Shareholders or MDA 1988 Optionholders  should  be
     based  upon  whether the consideration to be received  under
     the  Arrangement by current holders of MDA Common Shares  is
     equal  to  or  greater than the bottom end of the  range  of
     values of the MDA Common Shares currently held;

(b)  the  determination that it was not inappropriate to  utilize
     the  market  trading  price  of Orbital  Common  Shares  for
     purposes of its assessment;

(c)  in  assessing  the  MDA Common Shares and the  consideration
     offered  for  each  MDA Common Share,  an  assumption  of  a
     currency  exchange rate of US$0.7361 per Cdn$1.00 as  agreed
     on  July  31, 1995 and US$0.7509 per Cdn$1.00 on October  4,
     1995  and an assumption of a trading value of Orbital Common
     Shares in excess of US$15.00;

(d)  in  assessing  the MDA Common Shares, an approach  to  value
     based  on  MDA  remaining a going concern.  Liquidation  and
     break-up  methodologies were not considered  appropriate  in
     the  circumstances.  Nesbitt Burns considered that the  most
     appropriate  going  concern method to apply  to  MDA  was  a
     discounted  cash  flow ("DCF") approach.  The  DCF  approach
     takes into account the amount, timing and relative certainty
     of  future  cash  flows expected to be  generated  by  MDA's
     businesses   after   provision  for  cash   taxes,   capital
     expenditures  and  changes  in working  capital  and  before
     provisions  for payment to debtholders, interest  income  or
     expense  and  payment to equity holders ("Free Cash  Flow").
     These  Free  Cash  Flow projections were present  valued  by
     applying  an  appropriate weighted average cost  of  capital
     ("WACC").   The  DCF  analysis  included  consideration   of
     sensitivities  in respect of revenue growth, gross  margins,
     levels  of  WACC and the future growth rates  of  Free  Cash
     Flow;

(e)  in order to check the conclusions reached based upon the DCF
     analysis,  a comparison of a range of multiples  implied  by
     Nesbitt  Burns'  analysis to the range of multiples  derived
     from  an analysis of comparable transactions and the  market
     trading of comparable public companies; and

(f)  the  fact  that  the  consideration  value  offered  to  MDA
     Shareholders  of $7.35 per MDA Common Share,  provided  that
     the  Average  Closing  Price is greater  than  or  equal  to
     US$15.00, represents a 53% premium to the closing  price  of
     MDA Common Shares on the TSE on July 19, 1995 (the day prior
     to  MDA and Orbital entering into the No-Shop Agreement) and
     a  34% premium to the closing price of MDA Common Shares  on
     the  TSE on July 28, 1995 (the last trading day prior to the
     announcement of the proposed Arrangement).

Based  on and subject to the foregoing, Nesbitt Burns is  of  the
opinion  that, as of the date of the Opinion, the Arrangement  is
fair,  from  a  financial point of view, to the  holders  of  MDA
Common Shares and MDA 1988 Optionholders.

Plan of Arrangement

Under  the Plan of Arrangement, the following transactions, among
others, shall occur in the following order:

(a)  the authorized share capital of Acquisition shall be amended
     to  authorize  an  unlimited number of  Exchangeable  Shares
     having the rights, restrictions and limitations set forth in
     the  Exchangeable  Share  Provisions  and  10,000  Class   B
     Preferred   Shares  having  the  rights,  restrictions   and
     limitations  set  forth  in  Appendix  A  to  the  Plan   of
     Arrangement;

(b)  Acquisition shall issue 10,000 Class B Preferred  Shares  to
     Canadian  Imperial Bank of Commerce in partial consideration
     for  services rendered to Acquisition in connection with the
     Arrangement;

(c)  all  the  outstanding MDA Common Shares, except  MDA  Common
     Shares  owned  beneficially and of record by the  Qualifying
     Holdcos  and  MDA  Common  Shares  held  by  Dissenting  MDA
     Shareholders, shall be exchanged by the holders thereof  for
     Exchangeable  Shares,  the number  of  which  shall  be  the
     product  of such number of MDA Common Shares being exchanged
     and  the  Exchange Ratio.  Each former holder of MDA  Common
     Shares (other than the Qualifying Holdcos and Dissenting MDA
     Shareholders) shall receive the whole number of Exchangeable
     Shares  resulting  from the exchange of  such  holder's  MDA
     Common Shares for the consideration set out in the foregoing
     sentence  and in lieu of fractional Exchangeable Shares,  an
     amount  in  cash  equal to the fraction  multiplied  by  the
     Average Closing Price, payable in Canadian dollars;

(d)  all the outstanding shares of each of the Qualifying Holdcos
     shall  be  exchanged by the holders thereof for Exchangeable
     Shares,  the  number of which shall be the  product  of  the
     number of MDA Common Shares owned beneficially and of record
     by each respective Qualifying Holdco and the Exchange Ratio.
     Each  former  holder of shares of a Qualifying Holdco  shall
     receive  the  whole number of Exchangeable Shares  resulting
     from  the  exchange  of  all  such  holder's  shares  of   a
     Qualifying  Holdco  for the consideration  set  out  in  the
     foregoing  sentence  and in lieu of fractional  Exchangeable
     Shares,  an  amount in cash equal to the fraction multiplied
     by the Average Closing Price, payable in Canadian dollars;

(e)  each  of the Qualifying Holdcos shall be dissolved into  and
     its  assets distributed to Acquisition and for the  purposes
     of  such dissolution each of the Qualifying Holdcos will  be
     authorized to file articles of dissolution with the Director
     under  CBCA  at  such  time as the  board  of  directors  of
     Acquisition shall determine;

(f)  each   outstanding  MDA  Option,  except  options  held   by
     Dissenting MDA 1988 Optionholders, shall become an option to
     purchase  a  number of Orbital Common Shares  equal  to  the
     product  (rounded  to  the  nearest  whole  number)  of  the
     Exchange Ratio times the number of MDA Common Shares subject
     to  such MDA Option and will have an exercise price equal to
     the  exercise price for such option divided by the  Exchange
     Ratio  and the same vesting, expiration and other  terms  as
     such  MDA  Option  as  in effect immediately  prior  to  the
     Effective Time;

(g)  the MDA 1988 Option Plans will be amended to provide that if
     the  Orbital  Common Shares are changed or exchanged  for  a
     different   kind  or  number  of  securities,  the   options
     thereunder will be amended accordingly; and

(h)  the  name  of  Acquisition shall be  changed  to  "MacDonald
     Dettwiler Holdings Inc."

Contemporaneously with the Arrangement, Orbital  and  Acquisition
will  enter into the Voting and Exchange Trust Agreement and  the
Support  Agreement.   See "The Arrangement  and  the  Combination
Agreement - Description of Exchangeable Shares."

Post-Combination Share Ownership

Upon  completion  of  the Arrangement, Acquisition  will  be  the
beneficial  owner  of all the outstanding MDA Common  Shares  and
Orbital will be the beneficial and registered owner of all of the
Acquisition Common Shares.  The Acquisition Common Shares will be
the  only class of voting securities of Acquisition.  As a result
of the Arrangement, assuming an Exchange Ratio of .3136 (based on
an  assumed  Average Closing Price of US$17.25), the  former  MDA
Shareholders and holders of MDA Options will own or will have the
right  to  acquire (through ownership of Exchangeable Shares  and
Replacement Options) approximately 15% of the outstanding Orbital
Common  Shares  (including  shares issuable  to  holders  of  the
Exchangeable Shares and Replacement Options).

Qualifying Holdcos

Any  MDA Shareholder who wishes to transfer the MDA Common Shares
owned  by  it to a Qualifying Holdco and exchange the  shares  of
such  Qualifying Holdco for Exchangeable Shares pursuant  to  the
Plan  of Arrangement must notify MDA of its desire to do  so  not
less  than  five Business Days prior to the Special  Meeting  and
must   have  entered  into  a  Holding  Company  Agreement   with
Acquisition  and met all the conditions thereunder prior  to  the
date  of  the  Special Meeting.  Acquisition shall enter  into  a
Holding  Company Agreement with each MDA Shareholder who provides
the  aforementioned  notice to MDA and who meets  the  conditions
provided  in  the Holding Company Agreement.  Any MDA Shareholder
who  has  not  entered  into  a Holding  Company  Agreement  with
Acquisition on or before the date of the Special Meeting  or  who
has  entered into such agreement but has failed to meet all  such
conditions  to  the  satisfaction  of  Acquisition  in  its  sole
discretion  shall,  subject to the Plan of Arrangement  receiving
all  necessary  approvals, exchange his or her MDA Common  Shares
for   Exchangeable  Shares  as  an  MDA  Shareholder.   Any   MDA
Shareholder wishing to use a Qualifying Holdco should consult its
legal advisors and tax advisors.

Dissenting Holders

As  permitted in the Interim Order, MDA Shareholders and MDA 1988
Optionholders  may  exercise rights of dissent  with  respect  to
their  MDA Common Shares or the MDA Common Shares underlying  the
MDA  1988  Options  pursuant to and in the manner  set  forth  in
section  190  of  the CBCA and the Plan of Arrangement.   In  the
event  of  the  exercise  of  dissent  rights  by  any  MDA  1988
Optionholders, such MDA 1988 Options shall be deemed to have been
exercised  and  the exercise price of each such MDA  1988  Option
shall be satisfied by reducing the fair market value paid for the
MDA  Common  Shares  underlying such  MDA  1988  Option  by  such
exercise  price,  provided that if the MDA 1988  Optionholder  is
ultimately not entitled to be paid the fair market value for such
underlying  shares, such MDA 1988 Option shall be deemed  not  to
have  been exercised and shall become a Replacement Option.   See
"Dissenting Rights."

Description of Exchangeable Shares

Holders of Exchangeable Shares will have voting, liquidation  and
dividend  rights which are, as nearly as practicable,  equivalent
to  the  rights of holders of Orbital Common Shares.  Holders  of
Exchangeable Shares will have the right to exchange any  of  such
shares for an equal number (subject to adjustment in the event of
certain  capital  and corporate reorganizations  of  Orbital)  of
Orbital  Common  Shares plus the Dividend Amount attributable  to
such  shares, at any time prior to the Automatic Redemption  Date
and  subject to certain Call Rights of Orbital.  The Exchangeable
Shares   will   be  automatically  exchanged  on  the   Automatic
Redemption  Date  and  upon  the occurrence  of  certain  events,
including  the liquidation, dissolution or winding-up of  Orbital
or   Acquisition  or  the  default  by  Acquisition   under   the
Exchangeable  Share Provisions.  Acquisition  has  the  right  to
accelerate  the  Automatic Redemption Date  upon  not  less  than
75  days' written notice to the holders of Exchangeable Shares at
any   time   when  there  are  outstanding  less   than   400,000
Exchangeable  Shares held by persons other than Orbital  and  its
Affiliates.

Voting Rights

Holders of Exchangeable Shares will generally not be entitled  to
vote  at  meetings of the shareholders of Acquisition (except  as
required by law).  Orbital will be the only voting shareholder of
Acquisition.  Pursuant to the Voting and Exchange Trust Agreement
holders  of  Exchangeable Shares will be entitled to  vote  along
with  holders of Orbital Common Shares at meetings of the holders
of Orbital Common Shares.

As  of  the Effective Date, Orbital, Acquisition and the  Trustee
will  enter  into  the Voting and Exchange Trust Agreement  under
which  Orbital will issue one Special Voting Share to the Trustee
for  the  benefit of the holders of the Exchangeable Shares  (the
"Beneficiaries").  The Special Voting Share will carry the number
of  votes, exercisable at any meeting at which holders of Orbital
Common  Shares  are  entitled to vote, equal  to  the  number  of
Orbital  Common  Shares  into which the outstanding  Exchangeable
Shares  not  held  by Orbital or any of its Affiliates  are  then
exchangeable.

Each  Beneficiary  on the record date for any  meeting  at  which
holders  of  Orbital Common Shares are entitled to vote  will  be
entitled to instruct the Trustee to exercise that number  of  the
votes attached to the Special Voting Share equal to the number of
votes  that the Exchangeable Shares held by such holder would  be
entitled to if exchanged for Orbital Common Shares.  The  Trustee
will exercise each vote attached to the Special Voting Share only
as  directed by the relevant Beneficiary and, in the  absence  of
instructions  from a Beneficiary, will not exercise  such  votes.
Each  Beneficiary  may, upon instructing the  Trustee,  obtain  a
proxy from the Trustee entitling the Beneficiary to vote directly
at  the relevant meeting the votes attached to the Special Voting
Share  to  which the Beneficiary is entitled.  All  rights  of  a
Beneficiary  to  exercise votes attached to  the  Special  Voting
Share  will cease upon the exchange or redemption of Exchangeable
Shares  for Orbital Common Shares or the purchase of Exchangeable
Shares by Orbital pursuant to the Call Rights.

The  Trustee  will send to the Beneficiaries the notice  of  each
meeting at which holders of Orbital Common Shares are entitled to
vote, together with the related meeting materials and a statement
as  to  the  manner  in which the Beneficiary  may  instruct  the
Trustee  to  exercise the votes attaching to the  Special  Voting
Share, in each case at the same time as Orbital sends such notice
and  materials  to  the holders of Orbital  Common  Shares.   The
Trustee  will  also  send  to  the Beneficiaries  copies  of  all
information  statements, interim and annual financial statements,
reports and other materials and at the same time as, and  to  the
extent that, such materials are sent by Orbital to the holders of
Orbital  Common  Shares.   The Trustee  will  also  send  to  the
Beneficiaries all materials sent by third parties to  holders  of
Orbital  Common Shares to the extent such materials are  provided
by  Orbital  to the Trustee, including dissident proxy  circulars
and  tender  and  exchange offer circulars, as soon  as  possible
after  such materials are first sent to holders of Orbital Common
Shares.

Dividend Rights

Under  the Exchangeable Share Provisions, holders of Exchangeable
Shares will be entitled to receive dividends as follows:

          (i)  in the case of a cash dividend declared on Orbital
          Common Shares, holders of each Exchangeable Share  will
          be  entitled to receive the Canadian dollar  equivalent
          of  the  dividend declared on one Orbital Common  Share
          (subject to adjustment);

          (ii)  in  the  case  of  a stock dividend  declared  on
          Orbital Common Shares that is payable in Orbital Common
          Shares,  holders  of each Exchangeable  Share  will  be
          entitled to receive such number of Exchangeable  Shares
          as  is equal to the number of Orbital Common Shares  to
          be  paid  as  a  dividend on one Orbital  Common  Share
          (subject to adjustment); and

          (iii)                     in  the  case of  a  dividend
          declared  on  Orbital Common Shares in  property  other
          than  cash  or Orbital Common Shares, holders  of  each
          Exchangeable  Share will be entitled  to  receive  such
          type  and  amount  of  property  as  is  the  same   or
          economically equivalent to (as determined by the  board
          of  directors  of Acquisition) the type and  amount  of
          property  declared as a dividend on one Orbital  Common
          Share (subject to adjustment).

The  number  of Orbital Common Shares referred to in  determining
the  amount of dividends to be paid on one Exchangeable Share  is
subject  to  adjustment  in  the event  of  certain  capital  and
corporate   reorganizations  so  as  to  treat  the  holders   of
Exchangeable Shares in the same manner as the holders of  Orbital
Common   Shares   were   treated  with  respect   to   any   such
reorganization.   The  record date for the determination  of  the
holders  of  Exchangeable Shares entitled to receive payment  of,
and  the  payment date for, any dividend declared on Exchangeable
Shares  shall  be the same dates as the record date  and  payment
date,  respectively,  for the corresponding dividend  on  Orbital
Common Shares.

Retraction, Redemption and Exchange Right

Subject  to  applicable  law  and  the  Call  Rights  of  Orbital
described  below,  (i) holders of Exchangeable  Shares  shall  be
entitled  at  any time upon notice to the Depositary  to  require
Acquisition to redeem any of such Exchangeable Shares,  and  (ii)
on the Automatic Redemption Date, Acquisition shall redeem all of
the  then  outstanding Exchangeable Shares held by holders  other
than  Orbital  and its Affiliates.  Pursuant to  the  Voting  and
Exchange Trust Agreement, subject to applicable law and the  Call
Rights of Orbital described below, (i) upon the occurrence of and
during  the  continuance of an Insolvency Event or if Acquisition
shall  be  in  default  of  the terms of the  Exchangeable  Share
Provisions,  a  holder of Exchangeable Shares  may  instruct  the
Trustee  to  require  Orbital to purchase  any  or  all  of  such
holder's  Exchangeable  Shares and  (ii)  in  the  event  of  the
voluntary  or involuntary liquidation, dissolution or  winding-up
of   Orbital,  the  Exchangeable  Shares  will  automatically  be
exchanged  for  Orbital  Common  Shares.   In  the  case  of  any
retraction  or redemption of Exchangeable Shares by  Acquisition,
any  purchase or exchange of Exchangeable Shares pursuant to  the
Voting   and  Exchange  Trust  Agreement,  or  any  purchase   of
Exchangeable  Shares  by  Orbital pursuant  to  its  Call  Rights
described  below, each Exchangeable Share so retracted, redeemed,
purchased  or  exchanged shall (subject to required  withholding)
entitle the holder thereof to receive (i) an amount equal to  the
market  price of an Orbital Common Share, which amount  shall  be
satisfied  in  full  by delivery to such holder  of  one  Orbital
Common  Share  (subject to adjustment) and (ii)  payment  of  the
Dividend Amount.  Upon the exercise by Orbital of any of the Call
Rights  described below, the holder of Exchangeable  Shares  with
respect  and  to  which  such Call Right  is  exercised  will  be
authorized to sell and Orbital will be obligated to purchase  the
Exchangeable  Shares with respect to which  such  Call  Right  is
exercised.

Exercise of Retraction Rights of Holders and Orbital's Retraction
Call  Rights.   Holders  of  Exchangeable  Shares  may  effect  a
retraction  by  presenting  a  certificate  or  certificates   to
Acquisition's   transfer  agent  representing   the   number   of
Exchangeable Shares the holder desires to retract, together  with
a  written request (a "Retraction Request") specifying the number
of   Exchangeable  Shares  the  holder  wishes  to  retract   and
acknowledging  the  Retraction Call Right  of  Orbital  described
below, and such other documents as may be required to effect  the
retraction of the Exchangeable Shares.  Subject to the Retraction
Call  Right of Orbital, Acquisition shall redeem the Exchangeable
Shares  so  retracted effective at the close of business  on  the
sixth Business Day after the Retraction Request is received.

Upon  receipt of a Retraction Request, the transfer  agent  shall
immediately notify Orbital of such request.  If Orbital wishes to
exercise  its  Retraction  Call Right,  it  must  so  notify  the
transfer agent by the end of the third Business Day following the
receipt  by the transfer agent of the Retraction Request that  it
intends  to  exercise its Retraction Call Right to purchase  all,
but  not  less than all, of the Exchangeable Shares submitted  by
the holder thereof for retraction.

Exercise  of  Redemption  Rights  of  Acquisition  and  Orbital's
Redemption  Call  Rights.  Subject to Orbital's  Redemption  Call
Right,  the  Exchangeable Shares shall be redeemed by Acquisition
on  the Automatic Redemption Date.  Acquisition has the right  to
accelerate  the Automatic Redemption Date upon 75  days'  written
notice  to  the holders of Exchangeable Shares at any  time  when
there are outstanding less than 400,000 Exchangeable Shares  held
by  holders other than Orbital and its Affiliates.  Orbital shall
have  the  Redemption  Call Right, notwithstanding  any  proposed
redemption of the Exchangeable Shares by Acquisition as  outlined
above, to purchase on the Automatic Redemption Date all, but  not
less than all, of the outstanding Exchangeable Shares.

Orbital  shall, at least 75 days before the Automatic  Redemption
Date,  provide Acquisition and the transfer agent with notice  of
its  exercise  of the Redemption Call Right.  The transfer  agent
shall  thereafter  give  notice to each  holder  of  Exchangeable
Shares of Orbital's exercise of the Redemption Call Right.

Exercise  of Liquidation Exchange Right of Holders and  Orbital's
Liquidation  Call  Rights.  Pursuant to the Voting  and  Exchange
Trust  Agreement, upon the occurrence and during the  continuance
of  an Insolvency Event, or if Acquisition shall be in default of
the terms of the Exchangeable Share Provisions, a Beneficiary may
instruct the Trustee to require Orbital to purchase any or all of
the Exchangeable Shares held by the Beneficiary.  Acquisition and
Orbital will give immediate written notice to the Trustee of  the
occurrence of an Insolvency Event or any event that may, with the
passage  of  time or the giving of notice, become  an  Insolvency
Event,  or if Acquisition shall be in default of the Exchangeable
Share Provisions.  As soon as practicable thereafter, the Trustee
will   notify  each Beneficiary of such event or potential  event
and will advise the Beneficiary of its rights as described above.

Under  the  Plan  of  Arrangement, Orbital will  be  granted  the
Liquidation  Call Right, in the event of and notwithstanding  the
proposed  voluntary  or involuntary liquidation,  dissolution  or
winding-up  of  Acquisition, to purchase all, but not  less  than
all, of the Exchangeable Shares then outstanding and not held  by
Orbital  or its Affiliates.  The purchase by Orbital of  all  the
outstanding  Exchangeable  Shares  upon  the  exercise  of   such
Liquidation Call Right in that event will occur on the  effective
date of the voluntary or involuntary liquidation, dissolution  or
winding  up of Acquisition.  In addition, if Acquisition  is  not
legally  able  to  redeem all Exchangeable  Shares  tendered  for
retraction by a Beneficiary because it is insolvent or to  do  so
would  render  it  insolvent, Orbital shall  be  deemed  to  have
exercised  its  Liquidation  Call Right  with  respect  to  those
Exchangeable Shares which could not be redeemed.

Exercise  of Automatic Exchange Right in the Event of Liquidation
or  Winding  Up of Orbital.  Under the Voting and Exchange  Trust
Agreement,   in  the  event  of  the  voluntary  or   involuntary
liquidation,   dissolution   or  winding-up   of   Orbital,   all
outstanding  Exchangeable Shares will automatically be  exchanged
for  Orbital Common Shares, by way of a purchase by Orbital.  The
consideration  for the full purchase price for  the  Exchangeable
Shares  subject to such automatic exchange shall be delivered  to
the  holder  thereof at least five days prior  to  a  liquidation
event.

Deduction and Remittance of Withholding Tax

Delivery  of  Orbital Common Shares to a holder  of  Exchangeable
Shares  by  Acquisition  or Orbital,  as  the  case  may  be,  as
described  under "Exercise of Retraction Rights  of  Holders  and
Orbital's Retraction Call Rights," "Exercise of Redemption Rights
of  Acquisition and Orbital's Redemption Call Rights,"  "Exercise
of   Liquidation   Exchange  Right  of  Holders   and   Orbital's
Liquidation  Call  Rights," and "Exercise of  Automatic  Exchange
Right in the Event of Liquidation or Winding Up of Orbital," will
be  made, in the case of a holder that is a resident of Canada or
a  holder  that  is  a  non-resident of  Canada  who  provides  a
certificate  issued  under section 116 of the  Canadian  Tax  Act
specifying  a  certificate limit not less than  the  fair  market
value of the Exchangeable Shares, without any reduction in number
of  Orbital  Common Shares, and will be made, in the  case  of  a
holder  who is a non-resident of Canada and who does not  provide
such  a certificate, in a reduced number of Orbital Common Shares
to  reflect  compliance  with the obligation  of  Acquisition  or
Orbital,  as the case may be, to withhold and remit on behalf  of
such  non-resident holder, tax under section 116 of the  Canadian
Tax Act.

Anti-dilution and Capital Reorganizations

In  the event of stock splits or consolidations of Orbital Common
Shares, the distribution to the holders of Orbital Common  Shares
of options, warrants or rights to acquire securities or assets of
Orbital   for  less  than  their  fair  market  value  or   other
distribution  to holders of Orbital Common Shares  of  assets  of
Orbital, unless an economically equivalent distribution  is  made
by  Acquisition to holders of the Exchangeable Shares, the number
of  Orbital  Common Shares to be received upon  exchange  of  the
Exchangeable  Shares will be adjusted so as  to  give  equivalent
economic treatment to the holders of the Exchangeable Shares.  In
the  event  of  a capital reorganization of Orbital,  holders  of
Exchangeable  Shares  shall be entitled  to  receive  after  such
capital  reorganization, the number of shares or other securities
of Orbital or of a corporation resulting, surviving or continuing
from  the  capital  reorganization that such  holder  would  have
received had he or she been a holder of Orbital Common Shares  on
the record date of the capital reorganization.

Support Agreement

The  Support Agreement obligates Orbital and Acquisition to  take
or  refrain  from  taking certain actions so as  to  ensure  that
holders of Exchangeable Shares will receive the voting, dividend,
liquidation  and exchange rights described above.  In particular,
the  Support Agreement provides that: (i) Orbital shall not,  and
shall  cause  its Affiliates not to, exercise any  voting  rights
attached  to  Exchangeable Shares owned  by  it  or  any  of  its
Affiliates  on  any matter considered at meetings of  holders  of
Exchangeable  Shares  (including any approval  sought  from  such
holders   in  respect  of  matters  arising  under  the   Support
Agreement); (ii) Orbital shall not declare or pay any dividend on
the  Orbital  Common  Shares  unless  Acquisition  simultaneously
declares and pays the same or an economically equivalent dividend
(after,  in  the case of cash dividends, appropriate  adjustments
for  currency translations) on the Exchangeable Shares; and (iii)
Orbital  and Acquisition will do all things necessary  to  ensure
that  Acquisition  will  be  able to make  all  payments  on  the
Exchangeable Shares required in the event of (a) the liquidation,
dissolution  or winding-up of Acquisition, (b) the retraction  of
Exchangeable  Shares by a holder, or (c) the  redemption  of  the
Exchangeable Shares by Acquisition.

The  Support  Agreement obligates Orbital, in the  event  that  a
tender  offer, share exchange offer, issuer bid, takeover bid  or
similar  transaction with respect to Orbital  Common  Shares  (an
"Offer")  is proposed or recommended by Orbital, its shareholders
or  board of directors, or is otherwise effected with the consent
or   approval  of  Orbital's  board  of  directors,  to  use  all
commercially  reasonable efforts to take  such  actions  in  good
faith  as are necessary or desirable to enable and permit holders
of  Exchangeable Shares to participate in such Offer to the  same
extent and on an economically equivalent basis as the holders  of
the Orbital Common Shares, without discrimination.

The  Support Agreement also provides that Orbital will  take  all
actions necessary or desirable to cause all Orbital Common Shares
issued  and  delivered pursuant to the Combination Agreement  and
related  agreements to be freely tradeable by the holders thereof
(other  than any restrictions on transfer by reason of  a  holder
being a "control person" of Orbital for purposes of Canadian  law
or  an  "affiliate"  of  Orbital for purposes  of  United  States
securities  laws).   In  addition, Orbital  will  take  all  such
actions necessary to cause all such Orbital Common Shares  to  be
listed  or quoted for trading on all stock exchanges or quotation
systems  on  which  outstanding Orbital Common  Shares  are  then
listed  or  quoted  for trading.  The Orbital Common  Shares  are
currently  quoted  for  trading on  the  NASDAQ  and  it  is  not
anticipated  that such shares will be listed on any  other  stock
exchange or trading system.

The  Support  Agreement  also provides that,  without  the  prior
approval  of  Acquisition  and the holders  of  the  Exchangeable
Shares,  Orbital  will not distribute additional  Orbital  Common
Shares  or  rights  to  subscribe therefor  or  other  assets  or
evidences of indebtedness to all or substantially all holders  of
Orbital  Common Shares nor change the Orbital Common  Shares  nor
effect  any  reorganization  or other transaction  affecting  the
Orbital  Common  Shares,  unless  the  same  or  an  economically
equivalent distribution on, or change to, the Exchangeable Shares
(or in the rights of the holders thereof) is made simultaneously.
The  board  of directors of Acquisition is conclusively empowered
to determine in good faith and in its sole discretion whether any
corresponding  distribution  on or  change  to  the  Exchangeable
Shares  is the same as or economically equivalent to any proposed
distribution on or change to the Orbital Common Shares.

The  Support Agreement also provides that so long as there remain
outstanding any Exchangeable Shares not owned by Orbital  or  any
of  its  Affiliates,  Orbital will remain the  beneficial  owner,
directly or indirectly, of all outstanding shares of Acquisition,
other than Exchangeable Shares and the Class B Preferred Shares.

With the exception of administrative changes for the purposes  of
adding  covenants  for  the protection  of  the  holders  of  the
Exchangeable  Shares,  making  certain  necessary  amendments  or
curing ambiguities or clerical errors (in each case provided that
the  board of directors of each of Orbital and Acquisition is  of
the  opinion  that  such amendments are not  prejudicial  to  the
interests of the holders of the Exchangeable Shares), the Support
Agreement may not be amended without the approval of the  holders
of the Exchangeable Shares.

Market for Orbital Common Shares and Exchangeable Shares

The   Orbital   Common  Shares  issued  upon  exchange   of   the
Exchangeable  Shares  will  be freely tradeable  by  the  holders
thereof (other than any restrictions on transfer by reason  of  a
holder  being  a  "control  person" of Orbital  for  purposes  of
Canadian law or an "affiliate" of Orbital for purposes of  United
States  securities laws) and will be quoted for  trading  on  the
NASDAQ.  Although the transfer of Exchangeable Shares, subject to
receiving orders from applicable securities regulators, will  not
be  restricted under applicable securities laws, subject  to  the
above-noted  exceptions,  the Exchangeable  Shares  will  not  be
listed  on any stock exchange and MDA does not expect there  will
be  any market for the Exchangeable Shares.  See "The Arrangement
and  the Combination Agreement - Stock Exchange Listings" and  "-
Resale  of Exchangeable Shares and Orbital Common Shares Received
in the Arrangement."

The Combination Agreement

The  following  paragraphs summarize the material  terms  of  the
Combination   Agreement.    MDA   Shareholders   and   MDA   1988
Optionholders are urged to read the Combination Agreement in  its
entirety  for  a  more  complete description  of  the  terms  and
conditions  of the obligations of the parties in respect  of  the
Plan of Arrangement.

Actions to be Taken Prior to the Effective Time

Pursuant  to  the  Combination Agreement,  MDA,  Acquisition  and
Orbital  have agreed to perform certain obligations.  MDA  agreed
to  call all options to purchase MDA Common Shares presently held
by  shareholders of Earth Observation Sciences Ltd., a subsidiary
of  MDA.  Orbital and Acquisition covenanted to obtain exemptions
from registration or file a registration statement under the 1933
Securities Act qualifying the issue of the Orbital Common Shares,
and to obtain all orders necessary from securities regulators  in
Canada  so as to qualify the issuance and permit the free trading
of  the Exchangeable Shares and the Orbital Common Shares in  the
U.S.  and Canada subject only to restrictions on holders who  are
"control  persons"  in Canada or "affiliates"  in  the  U.S.   In
addition,  Orbital, Acquisition and MDA have agreed to  cooperate
in  the  preparation of this Proxy Circular, to take all  actions
necessary  to  qualify the issue of the Exchangeable  Shares  and
Orbital Common Shares under appropriate securities legislation in
order  to  permit the issue and free trading thereof, subject  to
the  above-noted exceptions, to call the Special Meeting, and  to
obtain the necessary court orders to permit the Arrangement to be
completed.

Business of MDA Pending the Arrangement

Pending  consummation of the Arrangement, and except as otherwise
consented  to  or approved in advance by Orbital in writing,  MDA
has  agreed  that  MDA  and its subsidiaries  will,  among  other
things,  operate  their  respective businesses  in  the  ordinary
course  of  business  consistent  with  past  practices  and  use
reasonable  efforts to preserve intact their respective  business
organizations;  not authorize for issuance or issue  any  capital
stock,  rights,  warrants,  options  or  convertible  or  similar
securities,  subject  to certain exceptions,  or  repurchase  any
capital   stock;  not  take  any  action  that  would  materially
adversely  affect  the ability of MDA or Orbital  to  obtain  the
approvals required to effect the transactions contemplated by the
Combination  Agreement;  and  not  take  any  action  that  would
materially affect the ability of MDA to perform its covenants and
agreements under the Combination Agreement.

Solicitation of Alternate Transactions

The  Combination Agreement provides that except  as  required  by
law,  MDA  will not, directly or indirectly: solicit,  encourage,
initiate  or  participate  in  any  negotiations,  inquiries   or
discussions with respect to any offer or proposal to acquire  all
or  any  significant part of MDA's business,  assets  or  capital
shares    whether    by   arrangement,   amalgamation,    merger,
consolidation,  other business combination, purchase  of  assets,
tender  or  exchange  offer or otherwise  (each  an  "Acquisition
Transaction");  or  disclose  any  information  not   customarily
disclosed  to any person concerning MDA's business or  properties
or afford to any person or entity access to its properties, books
or  records, except in the ordinary course of business consistent
with  past  practice  and  except  as  required  pursuant  to   a
governmental request for information; enter into or  execute  any
agreement  relating  to  an  Acquisition  Transaction,  plan   of
reorganization, or other agreement calling for the sale of all or
any  significant part of its business and properties; or make  or
authorize  any  public statement, recommendation or  solicitation
with  respect  to  any Acquisition Transaction or  any  offer  or
proposal  relating to an Acquisition Transaction other than  with
respect to the Arrangement.

The Combination Agreement provides that nothing contained therein
limits  the  power  of the MDA Board to withdraw  or  modify  any
recommendation  with  respect to the Plan  of  Arrangement  if  a
material  adverse  change occurs in the business  or  affairs  of
Orbital or in any of the information provided by Orbital on which
the   MDA  Board  has  based  any  recommendation  regarding  the
Arrangement.   If  any person proposes an unsolicited  bona  fide
acquisition  transaction  that in  the  opinion  of  MDA's  Board
(having  consulted its financial advisors) offers terms that  may
be  more favourable to the MDA Shareholders than pursuant to  the
Combination Agreement or the Plan of Arrangement, MDA shall  have
seven  business  days to consider such proposal, following  which
time the MDA Board may withdraw or modify any recommendation with
respect to the Plan of Arrangement only if to do so would, in the
opinion  of  the  MDA Board (having consulted  outside  counsel),
acting  reasonably,  be  a  proper  exercise  of  the  directors'
fiduciary duty.  Depending on the timing of the unsolicited  bona
fide  Acquisition  Transaction,  the  MDA  Board  may  support  a
proposal to postpone or adjourn the Special Meeting for not  more
than  10  business  days.   The Combination  Agreement  generally
requires  MDA  to  inform Orbital of any  such  bona  fide  offer
received by it or any related request for information.

In  addition,  MDA may terminate the Combination Agreement  if  a
bona   fide   offer  for  an  Acquisition  Transaction  providing
consideration for MDA Common Shares having a fair market value of
at least US$5.95 per share (based on prevailing currency exchange
rates  at  the date of the offer) is received, in which case  MDA
has agreed to pay Orbital a fee of US$750,000 upon completion  of
the transaction that gave rise to such termination.

Conditions to the Arrangement

Consummation of the Arrangement is subject to the satisfaction of
various conditions for the benefit of each of MDA or Orbital  and
both  of  them.   Conditions precedent for  the  benefit  of  MDA
include:  (i)  Orbital's  and Acquisition's  representations  and
warranties being correct on the Effective Date and Orbital having
performed  its covenants under the Combination Agreement  in  all
material respects; (ii) MDA receiving an opinion from counsel  to
Orbital in form and substance reasonably satisfactory to MDA; and
(iii)  the  Average Closing Price being equal to or greater  than
US$12.775.   Conditions  precedent for  the  benefit  of  Orbital
include:  (i) MDA's representations and warranties being  correct
on  the  Effective  Date and MDA having performed  its  covenants
under  the  Combination Agreement in all material respects;  (ii)
Orbital  having received an opinion of MDA's counsel in form  and
substance  reasonably satisfactory to Orbital; (iii) MDA's  Board
having  waived  the  applicable  provisions  of  the  Shareholder
Protection  Rights Plan; (iv) all necessary Affiliate  Agreements
having  been  executed;  (v) MDA having entered  into  Employment
Agreements  and Change of Control Agreements with  the  Chairman,
the  President  and each area general manager, as required,  (vi)
Dissenting MDA Shareholders and Dissenting MDA 1988 Optionholders
entitled  to  receive in the aggregate no more than  10%  of  the
aggregate number of Orbital Common Shares and the Orbital  Common
Shares  reserved  for issuance upon exercise of  the  Replacement
Options  to be issued pursuant to the Plan of Arrangement;  (vii)
Orbital having received a letter from its independent auditors to
the  effect  that  the  transaction meets  the  requirements  for
pooling  of  interests  accounting under U.S.  GAAP;  (viii)  all
required  third-party  consents  and  waivers  relating  to   the
Arrangement  having been obtained; and (ix) the  Average  Closing
Price being equal to or less than US$25.00.

In  addition,  for  the  benefit of both  MDA  and  Orbital,  the
following  conditions  must  be met:  (i)  the  approval  of  MDA
Shareholders  and  MDA 1988 Optionholders as required  under  the
Interim Order shall have been obtained and the Final Order  shall
have  been  issued by the Court; (ii) there shall be no temporary
restraining order, preliminary or permanent injunction  or  other
legal restraints or prohibitions, statutes, rules, regulations or
orders preventing consummation of the Arrangement; and (iii)  the
approval  for  quotation, subject to notice of issuance,  on  the
NASDAQ  of  the Orbital Common Shares to be issued in  connection
with the Arrangement shall have been obtained.

The parties entitled to the benefit of a particular condition may
waive compliance thereof.

Termination and Amendment

The  Combination Agreement may be terminated and the  Arrangement
may  be  abandoned  prior to the Effective  Date  notwithstanding
approval  by  the  MDA  Shareholders and MDA 1988  Optionholders,
under  the  circumstances specified therein,  including:  (i)  by
mutual consent of Orbital and MDA; (ii) by either Orbital or MDA,
if   the   Arrangement  shall  not  have  been   consummated   by
December 31, 1995 and if the terminating party has not caused the
failure  of the Arrangement to be consummated by its own  failure
to fulfil any of its obligations under the Combination Agreement;
(iii)  by either Orbital or MDA, if the MDA Shareholders  or  the
MDA   1988   Optionholders  fail  to  approve   the   Arrangement
Resolution; (iv) by either Orbital or MDA if there is a  material
breach  on  the  part of the other party in a  representation  or
warranty  or  covenant or agreement contained in the  Combination
Agreement  which is not cured within 10 days of  notice;  (v)  by
Orbital,   if  the  MDA  Board  has  withdrawn  or  changed   its
recommendation on the Arrangement in a manner adverse to Orbital,
or  shall  fail to affirm such support at Orbital's request;  and
(vi)  by  MDA, if it has received a bona fide offer to consummate
an Acquisition Transaction for consideration per MDA Common Share
having  a  fair  market  value  of at  least  US$5.95  (based  on
prevailing currency exchange rates on the date of such offer).

The  Combination  Agreement may be amended  by  an  agreement  in
writing  among  the  parties thereto at any  time  prior  to  the
Effective  Date; provided, however, that, after approval  of  the
Arrangement  by  the MDA Shareholders and MDA 1988 Optionholders,
no  amendment may be made which by law requires further  approval
of  such  shareholders  or optionholders,  without  such  further
approval.

Fees, Expenses and Indemnification

Except  as  described herein, all fees and expenses  incurred  in
connection  with  the Combination Agreement and the  transactions
contemplated  thereby  will be paid by the party  incurring  such
expenses, whether or not the Arrangement is consummated.

MDA  has  agreed  to  pay  Orbital a fee  of  US$750,000  if  the
Combination  Agreement  is terminated  by  MDA  because  MDA  has
received  a  bona  fide offer of an Acquisition  Transaction  for
consideration per MDA Common Share having a fair market value  of
at  least US$5.95 (based on prevailing currency exchange rates on
the  date of such offer), and such fee is payable only when  such
Acquisition Transaction is completed.

If  the  Combination Agreement is terminated as  a  result  of  a
breach by one of the parties, the party who has breached will pay
the actual out-of-pocket expenses of the others.

The  Combination  Agreement  provides  that  the  indemnification
provisions set forth in MDA's by-laws may not be modified for six
years  from the Effective Date in any manner that would adversely
affect  the rights thereunder of individuals who at the Effective
Date  were  MDA's directors or officers, unless such modification
is  required  by  law,  and requires Orbital  or  Acquisition  to
continue  in  effect with respect to any claims  arising  out  of
conduct  prior  to  the  Effective Date directors  and  officers'
insurance policies providing coverage of substantially  the  same
scope as is currently maintained by MDA; provided, however,  that
Orbital  may  amend, repeal or modify such by-law  provisions  or
cause  the  directors  and  officer's insurance  policies  to  be
modified or cancelled if it indemnifies such parties against  all
expenses  (including  attorney's  fees),  judgments,  fines   and
amounts  paid in settlement actually and reasonably  incurred  by
reason of the fact that such person was a director or officer  of
MDA,  in  connection  with any threatened, pending  or  completed
action,    suit   or   proceeding,   whether   civil,   criminal,
administrative or investigative, provided that such expenses were
incurred by such person in connection with such action,  suit  or
proceeding and provided that such person acted in good faith  and
in  a  manner he reasonably believed to be in or not  opposed  to
MDA's  best interests and had no reasonable cause to believe  his
conduct was unlawful.

MDA has agreed that, if the Arrangement is not effective, it will
indemnify each present and former director or officer of  MDA  or
any   of   its   subsidiaries  (collectively,  the   "Indemnified
Parties"),  to the fullest extent permitted under applicable  law
or  under  its by-laws, against any costs or expenses  (including
attorneys'  fees),  judgments, fines,  losses,  claims,  damages,
liabilities and amounts paid in settlement in connection with any
claim,  action, suit, proceeding or investigation, whether civil,
criminal,  administrative or investigative,  arising  out  of  or
pertaining  to any action or omission occurring while  they  were
directors, officers or employees for six years after the proposed
Effective Date.

Confidentiality Agreement

Each of Orbital and MDA has agreed to keep confidential, pursuant
to   a   confidentiality  agreement  dated  June  23,  1995  (the
"Confidentiality Agreement"), proprietary information provided by
the  other  party.  The Confidentiality Agreement contains  terms
restricting  the  disclosure and use of confidential  information
exchanged  between the two parties in evaluating the  Arrangement
and otherwise.

Agreements of MDA Affiliates

Rule 145 promulgated under the 1933 Securities Act regulates  the
disposition in the U.S. of securities by "affiliates" of  MDA  in
connection  with  the  Arrangement.  Affiliates  of  MDA,  as  so
defined, have delivered to Orbital executed Affiliate Agreements.
Under  such  Affiliate Agreements, each affiliate agrees  not  to
sell,  transfer or otherwise dispose of Orbital Common Shares  or
Exchangeable  Shares issued to the affiliate in  the  Arrangement
unless  such  sale, transfer or other disposition  (i)  has  been
registered  under  the  1933 Securities  Act,  (ii)  is  made  in
compliance  with  the requirements of Rule  145  under  the  1933
Securities  Act,  or  (iii) in the opinion of counsel  reasonably
acceptable  to  Orbital,  is otherwise exempt  from  registration
under  the  1933 Securities Act.  To comply with the requirements
of  pooling  of  interests accounting treatment,  each  Affiliate
Agreement  also restricts the sales of such shares prior  to  and
following the Arrangement until the publication and dissemination
by Orbital of consolidated financial results that include results
of combined operations of MDA and Orbital for at least 30 days on
a consolidated basis following the Effective Date.  The Affiliate
Agreements terminate if the Combination Agreement is terminated.

Court Approval and Completion of the Arrangement

Under the CBCA and pursuant to the Interim Order, the Arrangement
requires  Court approval, after approval of the MDA  Shareholders
and  MDA  1988  Optionholders has been obtained.   Prior  to  the
mailing  of  this Proxy Circular, MDA obtained the Interim  Order
providing  for  the calling, holding and conduct of  the  Special
Meeting  and  other procedural matters.  A copy  of  the  Interim
Order  is  attached as Appendix "D" to this Proxy Circular.   The
Notice of Application for the Final Order appears as Appendix "E"
to this Proxy Circular.

Subject to the approval of the Arrangement Resolution by the  MDA
Shareholders  and  the  MDA 1988 Optionholders,  the  hearing  in
respect  of  the  Final  Order  is scheduled  to  take  place  on
November  16,  1995  at  10:00 a.m. (Vancouver  time).   At  that
hearing, any MDA Shareholder, any MDA 1988 Optionholder,  or  any
other  interested  party  who wishes  to  participate  or  to  be
represented  or  to  present evidence or  arguments  may  do  so,
subject  to  filing  a notice of appearance with  the  Court  and
serving  such  notice of appearance upon MDA's solicitors  within
the  time as set forth in the Notice of Application for the Final
Order,  and  upon all other parties who have filed  a  notice  of
appearance, and satisfying other requirements as provided in  the
Interim  Order.   At the final hearing the Court  will  consider,
among  other  things,  the  fairness and  reasonableness  of  the
Arrangement.

Assuming  that  the  Final  Order  is  granted,  and  the   other
conditions to the Combination Agreement are satisfied, or  waived
by the party or parties entitled to do so, it is anticipated that
the  following will occur substantially simultaneously:  articles
of  arrangement  will be filed with the Director appointed  under
the  CBCA  to  give effect to the Arrangement;  and  the  Support
Agreement,  the  Voting  and Exchange  Trust  Agreement  and  the
various  other  documents  necessary  to  give  effect   to   the
Arrangement   and   other  transactions   contemplated   by   the
Combination Agreement will be executed and delivered.

Subject  to the foregoing, it is anticipated that the Arrangement
will be completed not later than November 30, 1995.

Accounting Treatment

The Arrangement is expected to be treated by Orbital as a pooling
of  interests  for  accounting purposes under  U.S.  GAAP.   This
accounting method permits the recorded assets and liabilities  of
both  Orbital  and  MDA to be carried forward on  a  consolidated
basis  by  Orbital,  after giving effect to the  Arrangement,  at
their  recorded historical amounts.  No recognition  of  goodwill
will be required as a result of the Arrangement and consequently,
there  will  be no amortization of goodwill from the  Arrangement
reflected in Orbital's future financial periods.

It   is  a  condition  to  Orbital's  obligation  to  effect  the
Arrangement  that  Orbital  receive an  opinion  from  KPMG  Peat
Marwick LLP, independent auditors of Orbital, to the effect  that
pooling  of  interests accounting treatment for  the  Arrangement
under  U.S.  GAAP is appropriate.  In the event  holders  of  MDA
Common  Shares and MDA 1988 Options in the aggregate entitled  to
receive greater than 10% of the sum of the Orbital Common  Shares
issuable  pursuant  to the Plan of Arrangement  and  the  Orbital
Common  Shares  reserved  for  issuance  upon  exercise  of   the
Replacement  Options,  shall properly  exercise  their  right  to
dissent,  the  Arrangement may not qualify  for  treatment  as  a
pooling of interests under applicable accounting rules.

Stock Exchange Listings

Exchangeable Shares

The  Exchangeable Shares will not be listed or posted for trading
on  any  stock exchange.  MDA does not expect there will  be  any
market for the Exchangeable Shares.

Orbital Common Shares

NASDAQ  has  conditionally approved inclusion of  the  additional
Orbital  Common Shares issuable upon exchange of the Exchangeable
Shares  and  the  Replacement  Options  for  quotation.   Orbital
expects that NASDAQ will grant final approval for such inclusion.

Eligibility for Investment in Canada

Exchangeable Shares

The  Exchangeable  Shares (including the Voting  Rights  and  the
Exchange Right) (a) will be "foreign property" under the Canadian
Tax   Act  for  trusts  governed  by  registered  pension  plans,
registered retirement savings plans, registered retirement income
funds and deferred profit sharing plans or for certain other tax-
exempt  persons, and (b) will not be qualified investments  under
the Canadian Tax Act for trusts governed by registered retirement
savings  plans, registered retirement income funds  and  deferred
profit sharing plans.

Voting Rights and Exchange Right

The  Voting  Rights and the Exchange Right will not be  qualified
investments and will be "foreign property" under the Canadian Tax
Act.

Orbital Common Shares

The Orbital Common Shares will be qualified investments under the
Canadian  Tax  Act  for trusts governed by registered  retirement
savings  plans, registered retirement income funds  and  deferred
profit sharing plans so long as such shares remain quoted on  the
NASDAQ  or another prescribed stock exchange.  The Orbital Common
Shares will be "foreign property" under the Canadian Tax Act.

Resale  of Exchangeable Shares and Orbital Common Shares Received
in the Arrangement

Canada

Orbital,  Acquisition and MDA have applied  for  rulings  of  the
British  Columbia  Securities Commission  ("BCSC"),  the  Ontario
Securities  Commission (the "OSC") and the securities commissions
of  certain other jurisdictions in Canada in which holders of MDA
Common  Shares reside, exempting any trade in Exchangeable Shares
or  in  Orbital Common Shares made in connection with or pursuant
to   the   Arrangement   from  the  applicable   prospectus   and
registration requirements of the securities legislation  of  such
jurisdictions.  If granted, these rulings would permit holders of
Exchangeable Shares who are not "control persons" of  Acquisition
to  sell  such securities in British Columbia, Ontario  and  such
other  jurisdictions, without being required to file a prospectus
in  respect thereof, provided that no unusual effort is  made  to
prepare  the market for any such sale or to create a  demand  for
such  securities and no extraordinary commission or consideration
is  paid  in respect thereof.  However, if such resale occurs  in
British  Columbia by a seller that is an insider of  Acquisition,
then,   as  a  further  condition  to  permitting  such   resale,
Acquisition  must  not be in default of any  requirement  of  the
Securities Act (British Columbia) or the regulations thereunder.

If   granted,  these  rulings  would  permit  residents  of  such
jurisdictions  who  are recipients of Orbital  Common  Shares  to
resell  such  securities provided that such resales are  executed
through  the facilities of a stock exchange or market outside  of
British Columbia, Ontario or such other jurisdiction, as the case
may be, and such resales are made in accordance with the rules of
the  stock exchange or market upon which such trades are made and
in  accordance with all laws applicable to such stock exchange or
market.

MDA,  Acquisition and Orbital have also applied for orders  under
the   Securities  Act  (British  Columbia),  the  Securities  Act
(Ontario)  and  the applicable securities laws of  certain  other
jurisdictions  in  Canada in which holders of MDA  Common  Shares
reside  to  permit all issuances of securities to be carried  out
pursuant to the Exchangeable Share Provisions and the Voting  and
Exchange  Trust  Agreement  to be exempt  from  the  registration
requirements of such Acts and applicable securities  laws.   Upon
completion  of the Arrangement, Acquisition will be  a  reporting
issuer under the Securities Act (British Columbia), but MDA  will
cease to be a reporting issuer under the Securities Act (Ontario)
and  the  applicable securities laws of the other  jurisdictions.
In  addition,  the  ruling  requested from  the  BCSC  would,  if
granted, exempt Acquisition from certain statutory financial  and
other  reporting requirements under the Securities  Act  (British
Columbia).   As a condition to granting the ruling  as  described
above,  Orbital will undertake, among other things, to file  with
the  appropriate  securities commissions  of  such  jurisdictions
copies  of all documents filed by it with the SEC and to send  to
all  holders of Exchangeable Shares resident in British  Columbia
and  such  other jurisdictions all disclosure materials that  are
sent  to  holders  of  Orbital Common Shares, including,  without
limitation,   copies  of  its  annual  reports  and   all   proxy
solicitation materials and, upon request, copies of its quarterly
reports.

United States

The  offer  and sale of the Exchangeable Shares, the  Replacement
Options  and  the Orbital Common Shares to be issued in  exchange
therefor  (collectively the "New Shares") will not be  registered
under  the  1933  Securities Act.  The Exchangeable  Shares,  the
Replacement  Options and the Orbital Common Shares issuable  upon
exchange of the Exchangeable Shares will be issued in reliance on
section  3(a)(10) of the 1933 Securities Act, which exempts  from
registration  under the 1933 Securities Act securities  that  are
issued  in  exchange for other outstanding securities  where  the
terms  and conditions of the issuance have been approved  by  any
court  expressly  authorized by law  to  grant  approval  to  the
proposed issuance, after a hearing upon the fairness of the terms
and  conditions of the issuance at which all persons to whom such
securities will be issued have the right to appear.  Orbital  has
been orally advised that it will be issued a letter from the  SEC
confirming  that  the  staff of the SEC will  not  recommend  any
enforcement action to the SEC if Acquisition, in reliance on  the
exemption  provided by section 3(a)(10), issues the  Exchangeable
Shares,  the  Replacement Options, and the Orbital Common  Shares
issuable in exchange for the Exchangeable Shares.

All  Orbital  Common Shares received by MDA Shareholders  in  the
Arrangement  will be freely transferable under the United  States
federal  securities  laws,  except  that  Orbital  Common  Shares
received  by persons who are deemed to be "affiliates"  (as  such
term is defined under the 1933 Securities Act) of MDA at the time
of  the  transaction  may be resold by such  affiliates  only  in
transactions    permitted   by   the   resale    provisions    of
Rule  145(d)(1), (2) or (3) promulgated under the 1933 Securities
Act  (or  Rule  145(d)(1) alone in the case of such  persons  who
become   affiliates  of  Orbital  upon  the  completion  of   the
Arrangement), or as otherwise permitted under the 1933 Securities
Act.  Rule 145(d)(1) generally provides that the "affiliates"  of
the acquired company may not sell securities of the issuer unless
pursuant  to  an  effective  registration  statement  or   unless
pursuant  to  the volume, current public information,  manner  of
sale  and  timing limitations of Rule 144 (excluding the  holding
period  requirements  of Rule 144).  These limitations  generally
require  that  (a) any sales made by the affiliate in  any  three
month  period not exceed the greater of (i) 1% of the outstanding
shares  of the issuer or (ii) the average weekly reported  volume
of  trading  in such shares on all national securities  exchanges
and/or  reported  through  an automated  quotation  system  of  a
registered securities association over a four-week period and (b)
that  such  sales  be  made in unsolicited, open  market  "broker
transactions"  or in transactions directly with a  market  maker.
Rules  145(d)(2)  and (3) generally provide  that  the  foregoing
limitations lapse for nonaffiliates of the issuer after a  period
of  two  or three years has elapsed since the date the securities
were  acquired from the issuer, respectively.  The average weekly
reported  volume of the Orbital Common Shares for the four  weeks
ending  September  29,  1995 was 848,250 Orbital  Common  Shares.
Persons who may be deemed to be affiliates of an issuer generally
include  individuals  or  entities that  directly  or  indirectly
control,  are  controlled by, or are under common  control  with,
such  issuer  and may include certain officers and  directors  of
such  issuer  as well as principal stockholders of  such  issuer.
See  "The  Arrangement and the Combination Agreement - Agreements
of MDA Affiliates."

Procedures for Exchange of Share Certificates by MDA Shareholders

At  or  promptly  after  the Effective  Time,  Acquisition  shall
deposit  with the Depositary, for the benefit of the  holders  of
MDA  Common  Shares and the holders of shares of  the  Qualifying
Holdcos   exchanged   pursuant  to  the  Plan   of   Arrangement,
certificates   representing   the  Exchangeable   Shares   issued
therefor.

A  Letter of Transmittal is enclosed with this Proxy Circular for
use   by   MDA   Shareholders  for  transmittal  of  certificates
representing MDA Common Shares.  Additional copies of the  Letter
of Transmittal may be obtained from the Depositary.  A subsequent
letter  of  transmittal may also be forwarded to MDA Shareholders
following the Effective Date.  The details of the procedures  for
exchange of certificates representing MDA Common Shares  and  the
deposit  of  such  certificates  with  the  Depositary  and   the
addresses  of  the office of the Depositary are set  out  in  the
Letter of Transmittal.

The    procedures   for   receiving   certificates   representing
Exchangeable Shares and/or Orbital Common Shares are as follows:

Return to Depositary of Letter of Transmittal

A  properly  completed Letter of Transmittal, or  any  subsequent
letter  of  transmittal, is to be forwarded to the Depositary  at
the office as set forth therein, together with the certificate(s)
representing the MDA Common Shares.  As soon as practicable after
the  surrender of certificates representing MDA Common Shares and
after   the   Effective   Date,  the  Depositary   will   deliver
certificates  representing  Exchangeable  Shares  and/or  Orbital
Common  Shares in accordance with the instructions set  forth  in
the   Letter   of  Transmittal  or  any  subsequent   letter   of
transmittal, as the case may be.

Election to Immediately Exchange Exchangeable Shares for  Orbital
Common Shares

MDA   Shareholders  who  wish  to  immediately   exchange   their
Exchangeable  Shares for Orbital Common Shares must complete  the
Letter  of Transmittal and indicate their election to immediately
exchange the Exchangeable Shares they are entitled to receive for
Orbital Common Shares in the election section therein.  If only a
part  of  such  holder's MDA Common Shares are to be  immediately
exchanged  for  Orbital Common Shares, the MDA Shareholder  shall
indicate  the  number of Exchangeable Shares to be so  exchanged.
If any MDA Shareholder elects to immediately exchange all or part
of  his  or her Exchangeable Shares for Orbital Common Shares,  a
certificate for the full number of Exchangeable Shares  to  which
that   holder  would  have  been  entitled  under  the  Plan   of
Arrangement shall be issued, the Depositary shall, by the  Letter
of Transmittal, be appointed an attorney to effect the retraction
on  behalf of the holder and the holder will receive certificates
representing Orbital Common Shares.  MDA has been advised that in
the  event of the retraction contemplated by the exercise of this
election,  Orbital intends to exercise its Redemption Call  Right
and purchase such Exchangeable Shares.  Orbital or Acquisition as
the  case may be, will require holders of Exchangeable Shares who
are  not  residents  of  Canada and who elect  to  retract  their
Exchangeable  Shares as described above to obtain  a  certificate
from  Revenue Canada pursuant to section 116 of the Canadian  Tax
Act,  specifying a certificate limit no less than the fair market
value  of  the  Orbital  Common  Shares  immediately  before  the
exchange  or redemption, as the case may be, and to deliver  such
certificate to Orbital or Acquisition.  See "The Arrangement  and
the Combination Agreement - Description of Exchangeable Shares  -
Deduction and Remittance of Withholding Tax."

Fractional Shares

No  certificates  or  scrip representing fractional  Exchangeable
Shares  or Orbital Common Shares will be issued.  In lieu of  any
such  fractional interests, each MDA Shareholder  entitled  to  a
fractional  interest  in Exchangeable Shares  or  Orbital  Common
Shares in consequence of the Arrangement or upon exchange of  the
Exchangeable  Shares for Orbital Common Shares  will  receive  an
equivalent  amount in cash (rounded to the nearest  whole  cent),
without  interest, from Acquisition equal to the Canadian  Dollar
Equivalent  (as defined in the Exchangeable Share Provisions)  of
the  product of such fraction, multiplied by the Average  Closing
Price.

Failure to Deposit Certificates Representing MDA Common Shares

Pending  the surrender of certificates formerly representing  MDA
Common  Shares, such certificates will, subject to the provisions
in  the  following sentence, be deemed to represent the right  to
receive  upon  such  surrender,  a certificate  representing  the
appropriate number of Exchangeable Shares (based on the  Exchange
Ratio),  any  cash  payment in lieu of a fractional  Exchangeable
Share,   and  any  Dividend  Amount.   Any  certificate  formerly
representing  MDA  Common  Shares not deposited  with  all  other
necessary documents on or prior to the sixth anniversary  of  the
Effective  Date shall cease to represent a claim or  interest  of
any  kind  or  nature  as  a shareholder  of  MDA,  the  relevant
Qualifying  Holdco or Acquisition, as the case may be.   On  such
date,  the  Exchangeable Shares to which  the  former  registered
holder  of  such  undeposited certificate was entitled  shall  be
deemed to have been surrendered to Acquisition together with  all
dividends,  distributions  and interests  held  for  such  former
registered holder.

Confirmation of Replacement Options

As  soon  as  practicable after the Effective Date, Orbital  will
forward  to each holder of a MDA Option, except a Dissenting  MDA
1988   Optionholder,  confirmation  of  the  Replacement  Option,
setting forth the number of Orbital Common Shares such holder  is
entitled to and the exercise price therefor.


INCOME TAX CONSIDERATIONS TO MDA SHAREHOLDERS AND OPTIONHOLDERS

Canadian Federal Income Tax Considerations

In  the opinion of Farris, Vaughan, Wills and Murphy, counsel for
MDA, the following is a summary of the principal Canadian federal
income  tax  considerations  generally  applicable  to  (i)   MDA
Shareholders  who,  for  purposes of the Canadian  Tax  Act,  are
residents  of  Canada, hold their MDA Common  Shares  as  capital
property  and  deal  at  arm's length with MDA,  Acquisition  and
Orbital,  (ii) MDA Shareholders who, for purposes of the Canadian
Tax  Act, have not been and will not be resident in Canada at any
time  while  they  have  held MDA Common Shares  or  Exchangeable
Shares,  and  deal  at  arm's length with  MDA,  Acquisition  and
Orbital, and (iii) MDA 1988 Optionholders.

This  summary is based on the current provisions of the  Canadian
Tax  Act,  all specific proposals to amend the Canadian  Tax  Act
publicly  announced by the Minister of Finance prior to the  date
hereof, and counsel's understanding of the current administrative
practices  of  Revenue  Canada. Except for  the  foregoing,  this
summary  does not take into account or anticipate any changes  in
law,  whether by legislative, administrative or judicial decision
or  action, nor does it take into account provincial, territorial
or  foreign income tax legislation or considerations,  which  may
differ  from  the  federal  income tax  considerations  described
herein.

WHILE  THIS SUMMARY IS INTENDED TO ADDRESS ALL PRINCIPAL CANADIAN
FEDERAL INCOME TAX CONSIDERATIONS, IT IS OF A GENERAL NATURE ONLY
AND  IS  NOT  INTENDED TO BE, NOR SHOULD IT BE CONSTRUED  TO  BE,
LEGAL OR TAX ADVICE TO ANY PARTICULAR MDA SHAREHOLDER OR MDA 1988
OPTIONHOLDER.  THEREFORE, SUCH HOLDERS SHOULD CONSULT  THEIR  OWN
TAX ADVISORS WITH RESPECT TO THEIR PARTICULAR CIRCUMSTANCES.   NO
ADVANCE  INCOME  TAX  RULING HAS BEEN OR WILL  BE  OBTAINED  FROM
REVENUE  CANADA TO CONFIRM THE TAX CONSEQUENCES  OF  ANY  OF  THE
TRANSACTIONS DESCRIBED HEREIN.

Holders of MDA Common Shares Resident in Canada

Exchange of MDA Common Shares for Exchangeable Shares.  A  holder
of MDA Common Shares who receives Exchangeable Shares in exchange
for  MDA  Common  Shares  pursuant to  the  Plan  of  Arrangement
(provided such holder is not considered to receive Voting  Rights
or  any  Exchange Right as partial consideration for  MDA  Common
Shares (see below)) will, unless such holder of MDA Common Shares
includes  any  portion  of  the  capital  gain  or  capital  loss
otherwise  determined in respect of the disposition of  such  MDA
Common  Shares in the holder's income tax return for the taxation
year  in  which  the exchange occurs, be deemed pursuant  to  the
"automatic"  rollover provisions of section 85.1 of the  Canadian
Tax  Act  to have disposed of such MDA Common Shares and will  be
deemed  to  have  acquired the Exchangeable  Shares  received  in
exchange  for  such  MDA Common Shares at a  cost  equal  to  the
adjusted cost base to such holder of such MDA Common Shares.

Based on the current administrative practise of Revenue Canada, a
holder of MDA Common Shares who receives cash not exceeding  $200
in  lieu  of  a fraction of an Exchangeable Share may reduce  the
adjusted  cost base of the Exchangeable Shares received  by  such
holder  by  the amount of such cash. Alternatively,  the  capital
gain or capital loss otherwise arising on the disposition of  the
fraction  of the MDA Common Share which is disposed of  for  such
cash may be reported.

If a holder of MDA Common Shares chooses to treat the exchange of
MDA   Common  Shares  for  Exchangeable  Shares  as   a   taxable
transaction, such holder of MDA Common Shares will be required to
recognize a capital gain (or capital loss) to the extent that the
fair  market  value of the Exchangeable Shares (and any  cash  in
lieu  of a fractional MDA Common Share) received in exchange  for
such  holder's MDA Common Shares immediately before the exchange,
net  of  any costs of disposition, exceeds (or is less than)  the
adjusted  cost  base  to  the holder of such  MDA  Common  Shares
immediately  before the exchange. The cost to the holder  of  the
Exchangeable  Shares  received in exchange for  such  MDA  Common
Shares  will  in this case be equal to the fair market  value  of
such Exchangeable Shares immediately before the exchange.

Where  the  transitional  rules  contained  in  the  Income   Tax
Application Rules, R.S.C. 1985, c.2 (5th Supplement), as  amended
(the  "ITARs"), apply to determine the adjusted cost  base  to  a
holder  of  MDA Common Shares of any MDA Common Shares  owned  by
such  holder  prior  to  1972 and continuously  thereafter  until
immediately  before the exchange of such shares for  Exchangeable
Shares,  such  rules may continue to apply for  the  purposes  of
determining  the  adjusted  cost  base  to  the  holder  of   any
Exchangeable Shares received in exchange therefor. Holders of MDA
Common  Shares  who may be affected by such rules should  consult
their own tax advisors.

Although  the  Plan  of Arrangement and the Voting  and  Exchange
Trust  Agreement  provide that Orbital  has  granted  the  Voting
Rights and Exchange Right to holders of the MDA Common Shares  in
consideration  of the Call Rights, it is possible Revenue  Canada
may  take the position that the Voting Rights and Exchange  Right
were acquired by a holder of MDA Common Shares in connection with
the exchange of the MDA Common Shares and not in consideration of
the  Call  Rights.  In such event, a holder of MDA Common  Shares
who  receives  Exchangeable Shares in  exchange  for  MDA  Common
Shares pursuant to the Plan of Arrangement would not qualify  for
the  "automatic"  rollover provisions  of  section  85.1  of  the
Canadian Tax Act.  In such circumstances, unless a holder of  MDA
Common Shares effects an election in respect of such exchange  in
accordance with the provisions of subsection 85(1) or (2) of  the
Canadian  Tax  Act  (as  described  below),  the  holder  may  be
considered  to have disposed of MDA Common Shares  in  a  taxable
transaction and the holder therefore may be required to recognize
a capital gain (or capital loss) to the extent that the aggregate
of the fair market value of the Exchangeable Shares (and any cash
in  lieu  of  a fractional MDA Common Share) and the fair  market
value of Voting Rights and Exchange Right (which MDA believes  to
be  nominal)  received in exchange for such holder's  MDA  Common
Shares  immediately  before the exchange, net  of  any  costs  of
disposition, exceeds (or is less than) the adjusted cost base  to
the  holder  of  such  MDA Common Shares immediately  before  the
exchange.   The  cost  to the holder of the  Exchangeable  Shares
received in exchange for such MDA Common Shares will in this case
be  equal  to  the fair market value of such Exchangeable  Shares
immediately before the exchange.

A  holder  may exchange MDA Common Shares and obtain  a  full  or
partial tax-free "rollover" in respect of such exchange by filing
with Revenue Canada (and, where applicable, with a provincial tax
authority)    an    election   (the   "Tax    Election")    under
subsection  85(1) of the Canadian Tax Act or, in the  case  of  a
partnership, under subsection 85(2) of the Canadian Tax Act  (and
the  corresponding  provisions of any applicable  provincial  tax
legislation)  made  jointly by the holder and Acquisition  (which
Acquisition, subject to the following paragraphs, has  agreed  to
make)  in  respect of the holder's MDA Common Shares so exchanged
pursuant  to  the  Plan of Arrangement and specifying  therein  a
"transfer  price,"  within  the  limitations  set  forth  in  the
Canadian  Tax Act, so that such MDA Common Shares will be  deemed
to  be  disposed  of  for proceeds of disposition  equal  to  the
transfer  price thereof.  Subject to the limitations set  out  in
subsection 85(1) of the Canadian Tax Act regarding the  specified
transfer  price, if the transfer price is equal to the  aggregate
of  the  adjusted cost bases of such MDA Common Shares determined
immediately before the exchange, no capital gain or capital  loss
will  be  realized, and to the extent that the transfer price  in
respect of such shares exceeds (or is less than) the aggregate of
the  adjusted  cost  bases thereof, such holder  will  realize  a
capital gain (or a capital loss).

Holders of MDA Common Shares who desire to effect the exchange of
their  MDA Common Shares pursuant to subsection 85(1) or  (2)  of
the  Canadian  Tax  Act, as the case may be,  should  obtain  the
appropriate federal election forms at any Revenue Canada District
Taxation  Office.   Where  necessary, the appropriate  provincial
election forms should be obtained from the income tax authorities
in that province.  These forms must be completed and submitted to
Acquisition   for  execution  at  the  following   address:   c/o
MacDonald, Dettwiler and Associates Ltd., 13800 Commerce Parkway,
Richmond,   British  Columbia,  V6V  2J3,  Attention:  Secretary.
Although the Tax Election involves certain complexities,  it  may
result in more favourable tax consequences to a holder than would
otherwise be the case if the Tax Election was not made in respect
of the exchange.

Holders  of MDA Common Shares who wish to effect the exchange  of
their  MDA Common Shares pursuant to subsection 85(1) or  (2)  of
the  Canadian  Tax  Act,  as the case may  be,  are  referred  to
Information  Circular  76-19R2 and  Interpretation  Bulletin  IT-
291R2,  published  by Revenue Canada, for information  respecting
the joint election to be made under the Canadian Tax Act.

The  comments provided herein with respect to joint elections are
provided  for general assistance only.  The law in this  area  is
complex  and  contains numerous technical requirements  including
limitations  applicable to the transfer price.   Compliance  with
such  requirements to ensure the validity of the joint  elections
will  be  the  sole  responsibility  of  the  holder  making  the
election.   Acquisition  will  not  be  responsible  for   proper
completion  and timely filing of such joint elections and  agrees
only  to  execute any properly completed election forms  received
from  holders  of  MDA Common Shares. In particular,  Acquisition
will  not  be  responsible  or liable for  any  taxes,  interest,
penalties,  damages  or expenses resulting from  the  failure  of
Acquisition  or  any  of  its agents, servants  or  officers,  to
properly  complete and return such joint election  forms  to  any
holder  for  filing by such holder with Revenue Canada  (and  the
appropriate  provincial authority, where applicable)  within  the
time  and in the prescribed form required under the Canadian  Tax
Act and any applicable provincial tax legislation.

Call Rights.  MDA is of the view and has advised counsel that the
Call  Rights, the Exchange Right and the Voting Rights have  only
nominal value.  The disposition by a holder of the Call Rights in
consideration  for  the  Voting Rights  and  the  Exchange  Right
should,  therefore, not result in any material  Canadian  federal
income  tax consequences.  Such determinations of value  are  not
binding  on Revenue Canada and counsel can express no opinion  on
matters  of  factual determination such as this.  If  the  Voting
Rights  or Exchange Right do have greater than nominal value  and
are  properly viewed as being received by a holder of MDA  Common
Shares  from  Orbital in consideration for  the  Call  Rights,  a
capital  gain would arise in an amount equal to the  fair  market
value of the Voting Rights and the Exchange Right and such holder
will  be  deemed  to have acquired such Voting  Rights  and  such
Exchange Right for a cost equal to their fair market value.

Dividends.   Dividends on Exchangeable Shares or  Orbital  Common
Shares  will  receive the following treatment under the  Canadian
Tax Act.

Exchangeable  Shares.   In the case of a shareholder  who  is  an
individual,  dividends received or deemed to be received  on  the
Exchangeable   Shares   will  be  included   in   computing   the
shareholder's  income, and will be subject to  the  gross-up  and
dividend   tax  credit  rules  normally  applicable  to   taxable
dividends received from taxable Canadian corporations.

The  Exchangeable Shares will be "taxable preferred  shares"  and
"short-term  preferred shares" for purposes of the  Canadian  Tax
Act, and accordingly, dividends received or deemed to be received
on  the  Exchangeable Shares will not be subject to the  10%  tax
under  Part  IV.1 of the Canadian Tax Act applicable  to  certain
corporations.

If  the Support Agreement is deemed to be a "guarantee agreement"
under the Canadian Tax Act and if Acquisition or any person  with
whom  Acquisition does not deal at arm's length is  a  "specified
financial institution" under the Canadian Tax Act at a  point  in
time  that  a  dividend  is paid on an Exchangeable  Share,  then
dividends received or deemed to be received by a shareholder that
is  a  corporation  will not be deductible in  computing  taxable
income  but  will  be  fully includable in taxable  income  under
Part  I  of  the  Canadian Tax Act.  Such dividend  will  not  be
subject  to  tax  under  Part IV of  the  Canadian  Tax  Act.   A
corporation  will generally be a specified financial  institution
for  these  purposes if it is a bank, a trust company,  a  credit
union,  an insurance corporation or a corporation whose principal
business  is  the  lending  of money to  persons  with  whom  the
corporation is dealing at arm's length or the purchasing of  debt
obligations issued by such persons or a combination thereof,  and
corporations   controlled  by  or  related  to   such   entities.
Acquisition  has  informed counsel that it is of  the  view  that
neither  it  nor any person with whom it does not deal  at  arm's
length  is a specified financial institution at the current  time
but  there  can be no assurance that this status will not  change
prior  to  the  time  any  dividend on an Exchangeable  Share  is
received or deemed to be received by a corporate shareholder.

Subject to the foregoing, in the case of a shareholder that is  a
corporation,  other than a "specified financial  institution"  as
defined in the Canadian Tax Act, dividends received or deemed  to
be   received  on  the  Exchangeable  Shares  will  normally   be
deductible in computing its taxable income.

A  shareholder that is a "private corporation" (as defined in the
Canadian Tax Act) or any other corporation resident in Canada and
controlled  or deemed to be controlled directly or indirectly  in
any manner whatsoever by or for the benefit of an individual or a
related group of individuals may be liable under Part IV  of  the
Canadian  Tax Act to pay a refundable tax of 33 1/3% on dividends
received  or deemed to be received on the Exchangeable Shares  to
the  extent  that such dividends are deductible in computing  the
shareholder's taxable income.

Orbital  Common Shares.  Dividends on Orbital Common Shares  will
be  included  in the recipient's income for the purposes  of  the
Canadian  Tax  Act.   Such dividends received  by  an  individual
shareholder will not be subject to the gross-up and dividend  tax
credit rules in the Canadian Tax Act.  A corporation which  is  a
shareholder will include such dividends in computing  its  income
and  generally will not be entitled to deduct the amount of  such
dividends  in computing its taxable income.  United  States  non-
resident  withholding tax on such dividends will be eligible  for
foreign tax credit or deduction treatment where applicable  under
the Canadian Tax Act.

Redemption or Exchange of Exchangeable Shares.  On the redemption
(including  a retraction) of an Exchangeable Share by Acquisition
for  an Orbital Common Share, the holder of an Exchangeable Share
will  be  deemed to have received a dividend equal to the amount,
if  any, by which the redemption proceeds (the fair market  value
at  the  time  of  the  redemption of the  Orbital  Common  Share
received  by  the shareholder from Acquisition on the  redemption
plus  the  amount,  if  any,  of  all  unpaid  dividends  on  the
Exchangeable Share) exceeds the paid-up capital at that  time  of
the  Exchangeable  Share so redeemed.  The  amount  of  any  such
deemed dividend will be subject to the tax treatment accorded  to
dividends described above.  On the redemption, the holder  of  an
Exchangeable  Share will also be considered to have  disposed  of
the  Exchangeable Share, but the amount of such  deemed  dividend
will  be  excluded  in  computing the shareholder's  proceeds  of
disposition for purposes of computing any capital gain or capital
loss  arising on the disposition of the Exchangeable  Share.   In
the  case  of a shareholder that is a corporation, it is possible
that in some circumstances the amount of any such deemed dividend
may  be  treated as proceeds of disposition and not as a dividend
and accordingly, such corporate shareholders should consult their
own tax advisors for specific advice in these circumstances.

On  the  exchange of an Exchangeable Share by the holder  thereof
with  Orbital for an Orbital Common Share pursuant  to  the  Call
Rights  or the Exchange Right, the holder will in general realize
a  capital gain (or a capital loss) equal to the amount by  which
the proceeds of disposition of the Exchangeable Share, net of any
reasonable  costs of disposition, exceed (or are less  than)  the
adjusted  cost  base  of the Exchangeable  Share  to  the  holder
thereof.  For these purposes, the proceeds of disposition will be
the value of an Orbital Common Share at the time of exchange plus
the amount of all unpaid dividends on the Exchangeable Share.

The  cost  of an Orbital Common Share received on the retraction,
redemption or exchange of an Exchangeable Share will be equal  to
the fair market value of the Orbital Common Share at the time  of
such event.

If  the  holder of an Exchangeable Share is a corporation,  or  a
partnership  or a trust of which a corporation is  a  partner  or
beneficiary,  as the case may be, the amount of any loss  arising
from a disposition or deemed disposition of an Exchangeable Share
in  certain  circumstances  may  be  reduced  by  the  amount  of
dividends received or deemed to have been received by it on  such
share.

Because  of  the existence of the Call Right, a holder exercising
the  right  of  retraction in respect of  an  Exchangeable  Share
cannot control whether such holder will receive an Orbital Common
Share  by  way  of  redemption  of  the  Exchangeable  Share   by
Acquisition  or by way of purchase of the Exchangeable  Share  by
Orbital.   As  described above, the Canadian federal  income  tax
consequences  of a redemption differ from those  of  a  purchase.
However, a holder who exercises the right of retraction  will  be
notified if the Call Right will not be exercised by Orbital,  and
if  such holder does not wish to proceed, such holder may  cancel
the  notice  of retraction and retain such holder's  Exchangeable
Share.

Dissenting  MDA Shareholders.  A holder of MDA Common  Shares  is
permitted  to  dissent from the Arrangement  in  compliance  with
section 190 of the CBCA and the Interim Order.  A MDA Shareholder
who  dissents from the Arrangement Resolution in compliance  with
section  190  of  the CBCA will be entitled,  in  the  event  the
Arrangement becomes effective, to be paid by MDA the  fair  value
of  the MDA Common Shares held by such shareholder determined  at
the appropriate date.  See "Dissenting Rights."  A Dissenting MDA
Shareholder  will be considered to receive a deemed dividend  and
to  have disposed of the MDA Common Shares in accordance with the
discussion  above  of the redemption of the Exchangeable  Shares.
Additional   income  tax  considerations  may  be   relevant   to
Dissenting MDA Shareholders who fail to perfect or withdraw their
claims  pursuant  to  the  rights  of  dissent.   Dissenting  MDA
Shareholders  should consult their own tax advisors for  specific
advice in these circumstances.

Foreign  Property.   The  Exchangeable  Shares  will  be  foreign
property  under  the  Canadian Tax Act  for  trusts  governed  by
registered  pension plans, registered retirement  savings  plans,
registered  retirement income funds and deferred  profit  sharing
plans or for certain other tax-exempt persons.  The Voting Rights
and  Exchange  Right will be foreign property under the  Canadian
Tax  Act.   Orbital Common Shares will be foreign property  under
the Canadian Tax Act.

Qualified  Investments.   The Exchangeable  Shares  will  not  be
qualified  investments  under the Canadian  Tax  Act  for  trusts
governed  by  registered  retirement  savings  plans,  registered
retirement income funds and deferred profit sharing plans and  at
the  end of each month, such trusts will be liable to pay  a  tax
under the Canadian Tax Act of 1% of the fair market value of  the
Exchangeable  Shares.  Orbital Common Shares  will  be  qualified
investments under the Canadian Tax Act for such plans as long  as
such shares remain listed on the NASDAQ (or are listed on certain
other exchanges).  The Voting Rights and Exchange Right will  not
be qualified investments under the Canadian Tax Act.

Holders of MDA Common Shares Not Resident in Canada

Generally,  MDA  Common  Shares  will  not  be  taxable  Canadian
property  provided that those shares are listed on  a  prescribed
stock exchange in Canada, the holder does not use or hold, and is
not  deemed  to use or hold, the MDA Common Shares in  connection
with  carrying  on a business in Canada and the  holder,  persons
with  whom  such  holder does not deal at arm's  length,  or  the
holder and such persons, has not owned (or had under option)  25%
or  more  of  the  issued shares of any class or  series  of  the
capital stock of MDA at any time within five years preceding  the
date in question.  The MDA Common Shares are currently listed  on
a prescribed stock exchange in Canada under the Canadian Tax Act.
Such  a  holder of MDA Common Shares will not be subject  to  tax
under the Canadian Tax Act on the exchange of MDA Common Shares.

Generally,  the  Exchangeable Shares  will  be  taxable  Canadian
property,  and on the redemption (including a retraction)  of  an
Exchangeable Share by Acquisition for an Orbital Common Share,  a
non-resident  holder of an Exchangeable Share will be  considered
to  have  received  a deemed dividend and be considered  to  have
disposed of the Exchangeable Share for proceeds of disposition in
an amount as described above for residents of Canada.  The amount
of   such   deemed  dividend  will  be  subject  to  non-resident
withholding  tax  under the Canadian Tax Act as described  below,
and Acquisition will require the non-resident holder to obtain  a
certificate pursuant to section 116 of the Canadian  Tax  Act  as
described below.  On the exchange of an Exchangeable Share by the
non-resident  holder thereof with Orbital for an  Orbital  Common
Share,  the non-resident holder of an Exchangeable Share will  be
considered  to  have  disposed  of  the  Exchangeable  Share  for
proceeds  of  disposition in an amount  as  described  above  for
residents  of  Canada, and Orbital will require the  non-resident
holder  to  obtain a certificate pursuant to section 116  of  the
Canadian Tax Act as described below.

Orbital or Acquisition, as the case may be, will require the non-
resident  holder of the Exchangeable Shares to apply  to  Revenue
Canada  to  obtain a certificate pursuant to section 116  of  the
Canadian Tax Act, specifying a certificate limit no less than the
fair market value of the Orbital Common Shares immediately before
the  exchange  or redemption, as the case may be.  A  certificate
should generally be obtainable from Revenue Canada where the non-
resident holder of Exchangeable Shares pays an amount on  account
of  tax  arising on a disposition or establishes that no  tax  is
payable.   Where no certificate is obtained by such  non-resident
holder   or   where  a  certificate  is  obtained  specifying   a
certificate limit less than the fair market value of the  Orbital
Common Shares, Orbital or Acquisition will withhold and remit  to
Revenue Canada within 30 days after the end of the month in which
Orbital or Acquisition acquires the Exchangeable Shares,  as  tax
on behalf of the non-resident holder, 33J% of the amount by which
the  fair  market value of the Orbital Common Shares exceeds  the
certificate  limit  specified  in  the  certificate  or   if   no
certificate  is obtained, 33J% of the fair market  value  of  the
Orbital Common Shares, and Acquisition or Orbital will deliver to
the non-resident holder a reduced number of Orbital Common Shares
to  reflect  such  payment to Revenue Canada.   Holders  of  such
Exchangeable Shares may be exempt from liability to pay tax under
the  Canadian  Tax  Act  by virtue of any applicable  tax  treaty
between  Canada and the country in which they are resident.   For
example, under the Canada-United States Income Tax Convention,  a
resident  of  the United States who has not been  a  resident  of
Canada at any time during the ten years immediately preceding the
exchange  of the Exchangeable Shares should generally  be  exempt
from  such  tax  under  the  Canadian  Tax  Act.   However,  such
exemption  will  not  relieve Acquisition or Orbital  from  their
liability  to  withhold or remit amounts  to  Revenue  Canada  on
account of tax where the non-resident holder has not provided the
appropriate certificate as discussed above.  Non-resident holders
of  Exchangeable Shares should consult their own tax advisors for
specific advice in these circumstances.

Dividends  paid  or deemed to be paid on the Exchangeable  Shares
are  subject  to non-resident withholding tax under the  Canadian
Tax  Act  at  the rate of 25%, although such rate may be  reduced
under  the  provisions of an applicable income tax  treaty.   For
example,  under  the Canada-United States Income Tax  Convention,
the rate is generally reduced to 15%.

A  holder  whose Exchangeable Shares are redeemed  (either  under
Acquisition's  redemption  right  or  pursuant  to  the  holder's
retraction  rights)  will  be deemed to  receive  a  dividend  as
described  above,  which  deemed  dividend  will  be  subject  to
withholding tax as described in the preceding paragraph.

MDA 1988 Optionholders

Pursuant  to  the Canadian Tax Act, a holder of each  outstanding
MDA  1988  Option which becomes a Replacement Option pursuant  to
the  Plan  of Arrangement will be deemed not to have disposed  of
the  MDA  1988  Option and not to have acquired  the  Replacement
Option,  provided  the  value of the  Replacement  Option  is  no
greater than the value of the MDA 1988 Option.  Furthermore,  the
Replacement Option shall be deemed to be the same option as,  and
a  continuation  of,  the MDA 1988 Option and  Orbital  shall  be
deemed to be the same corporation as, and a continuation of, MDA.

Dissenting MDA 1988 Optionholders.  A holder of MDA 1988  Options
is permitted to dissent from the Arrangement and shall be deemed,
pursuant  to  the Plan of Arrangement and the Interim  Order,  to
have  exercised the MDA 1988 Options with respect to which he  or
she  is exercising the dissent and the exercise price under  each
such  MDA  1988  Option shall be deemed to  be  paid  by  set-off
against the fair value paid for MDA Common Shares under such  MDA
1988 Option, determined at the appropriate date.  See "Dissenting
Rights."  A benefit (the "Benefit Amount") equal to the amount of
such  payment by MDA to the Dissenting MDA 1988 Optionholder will
be  deemed  to  have  been received by the  Dissenting  MDA  1988
Optionholder because of his or her employment and will  be  added
to  the  taxable  income of such holder, and where  the  exercise
price  for  the MDA Common Share under each such MDA 1988  Option
was  not less than the fair market value of the MDA Common  Share
at  the  time the agreement for the MDA 1988 Option was made,  an
amount  equal to one fourth of the Benefit Amount may be deducted
by  the  Dissenting  MDA 1988 Optionholder  for  the  purpose  of
computing   taxable   income.    Where   Dissenting   MDA    1988
Optionholders  are considered to have acquired MDA Common  Shares
under   his  or  her  MDA  1988  Option,  Dissenting   MDA   1988
Optionholders would also be considered to have received a  deemed
dividend.  Dissenting MDA 1988 Optionholders should consult their
own tax advisors for specific advice in these circumstances.

United States Federal Income Tax Considerations

In  the  opinion  of  Paul, Weiss, Rifkind, Wharton  &  Garrison,
United  States  counsel  to  MDA, the  following  summarizes  the
principal U.S. federal income tax considerations arising from and
relating  to the Arrangement, including the receipt and ownership
of  Exchangeable  Shares  and Orbital  Common  Shares,  that  are
generally  applicable to MDA Shareholders that are U.S.  citizens
or  residents, domestic corporations, domestic partnerships,  and
estates  or  trusts subject to U.S. federal income tax  on  their
income  regardless of source ("U.S. Holders") and to certain  MDA
Shareholders that are not U.S. Holders.  This summary is intended
for general information only.  It does not discuss all aspects of
U.S. federal income taxation that may be relevant to a particular
U.S.  Holder  (including potential application of the alternative
minimum  tax) or to certain types of investors subject to special
treatment  under the U.S. federal income tax laws  (for  example,
banks, life insurance companies, tax-exempt organizations, broker-
dealers  or U.S. Holders who received their MDA Common Shares  as
compensation), nor does it discuss any aspect of state, local  or
foreign tax laws.  Additionally, the following summary is limited
to  U.S.  Holders  (i)  who hold MDA Common  Shares  as  "capital
assets"  within the meaning of section 1221 of the United  States
Internal Revenue Code of 1986, as amended (the "Code"), (ii)  who
will  hold  Exchangeable  Shares and  Orbital  Common  Shares  as
"capital assets," (iii) who do not actually or constructively own
(and  have  not  at  any time in the preceding  five-year  period
actually or constructively owned) 10% or more of the voting stock
of  MDA  or  Acquisition,  as the case may  be,  and  (iv)  whose
ownership,  receipt  and disposition of Exchangeable  Shares  and
Orbital   Common  Shares  is  not  attributable  to  a  permanent
establishment in Canada.  The summary also does not  discuss  the
federal  income tax consequences of any transaction  involving  a
Qualifying Holdco.

This summary is based on laws, regulations, rulings and decisions
currently in effect, all of which are subject to change, possibly
with  retroactive effect.  In addition, U.S. Holders should  note
that there is no statutory, judicial, or administrative authority
that  directly addresses certain of the U.S. federal  income  tax
consequences  of  the issuance and ownership of  instruments  and
rights  comparable to the Exchangeable Shares, the Voting Rights,
the  Exchange  Right  and  the  Call  Rights.   Consequently  (as
discussed  more  fully below), many aspects of the  U.S.  federal
income  tax treatment of the Arrangement, including the  receipt,
ownership  and disposition of Exchangeable Shares, are uncertain.
No advance income tax ruling has been sought or obtained from the
Internal  Revenue Service ("IRS") regarding the tax  consequences
of  any of the transactions described herein.  Accordingly, it is
possible  that  the U.S. federal income tax consequences  of  the
Arrangement  and the holding and disposition of the  Exchangeable
Shares may differ from those described below.

U.S. HOLDERS AND NON-U.S. HOLDERS ARE URGED TO CONSULT THEIR  OWN
TAX  ADVISORS WITH RESPECT TO THE U.S. FEDERAL, STATE, AND  LOCAL
TAX   CONSEQUENCES  AND  THE  FOREIGN  TAX  CONSEQUENCES  OF  THE
ARRANGEMENT,  INCLUDING THE RECEIPT AND OWNERSHIP OF EXCHANGEABLE
SHARES OR ORBITAL COMMON SHARES.

Taxation of U.S. Holders

The Arrangement.  Although the matter is not free from doubt, MDA
and Orbital have been advised that there is a reasonable basis on
which  to  conclude  that the exchange of MDA Common  Shares  for
Exchangeable Shares pursuant to the Arrangement will constitute a
taxable transaction for U.S. federal income tax purposes, and MDA
understands  that  Orbital intends to report the  exchange  in  a
manner consistent with the foregoing.

If the exchange is a taxable transaction:

(1)  a   U.S.  Holder  who  receives  Exchangeable  Shares  would
     recognize  capital gain or loss in an amount  equal  to  the
     difference between the fair market value of the Exchangeable
     Shares  received  (together with cash received  in  lieu  of
     fractional  shares (if any)) and the adjusted basis  of  the
     MDA Common Shares surrendered in the exchange;

(2)  such capital gain or loss would be long-term capital gain or
     loss  if the MDA Common Shares exchanged have been held  for
     more than one year at the time of the exchange and otherwise
     would be short-term capital gain or loss;

(3)  an exchanging U.S. Holder would take as its tax basis in the
     Exchangeable   Shares   the  fair  market   value   of   the
     Exchangeable Shares at the time of the exchange;

(4)  the  holding  period of the Exchangeable Shares received  by
     the U.S. Holder in the exchange would begin on the day after
     the U.S. Holder receives the Exchangeable Shares; and

(5)  gain  realized  on  the exchange of MDA  Common  Shares  for
     Exchangeable  Shares  generally would  be  treated  as  U.S.
     source gain.

It  is  possible  that  the IRS may take the  position  that  the
receipt of Exchangeable Shares in exchange for MDA Common  Shares
is not a taxable event.  In such case:

(1)  a  U.S. Holder generally would not recognize gain or loss on
     the  receipt of the Exchangeable Shares; such a U.S.  Holder
     would,  however, be required to recognize gain to the extent
     of the receipt of cash in lieu of fractional shares (if any)
     and, possibly as discussed below, the value, if any, of  the
     Voting  Rights,  Exchange Right and other rights  under  the
     Support Agreement;

(2)  the  tax basis of the Exchangeable Shares would be equal  to
     the  tax  basis of the MDA Common Shares exchanged  therefor
     (reduced  by  the  tax basis allocated to  fractional  share
     interests); and

(3)  the  holding period of the Exchangeable Shares would include
     the  holding  period  of  the MDA  Common  Shares  exchanged
     therefor.

The  IRS  may assert that the Exchangeable Shares and certain  of
the rights associated therewith constitute "offsetting positions"
for  purposes of the straddle rules set forth in section 1092  of
the  Code.   In such case, the holding period of the Exchangeable
Shares  would  not  increase while held by  a  U.S.  Holder,  and
interest  incurred in carrying the Exchangeable Shares would  not
be deductible by a U.S. Holder.

MDA  believes  that  the  Voting Rights and  the  Exchange  Right
received  and  the  Call  Rights  conveyed  by  MDA  shareholders
pursuant  to  the Combination Agreement and the Arrangement  will
have  only  nominal value and, therefore, that their  receipt  or
conveyance  will not result in any material U.S.  federal  income
tax  consequences.  Further, the exchange of the Call Rights  for
the  Voting  Rights and the Exchange Right may not be taxable  to
such U.S. Holders because such U.S. Holders may be deemed to have
granted  a  purchase option to Orbital, which  is  not  generally
treated  as a taxable event for U.S. federal income tax  purposes
(although,  under this approach, the value of the  Voting  Rights
and  the  Exchange  Right would be taken into  account  upon  the
exercise  or lapse of the Call Rights).  It is possible, however,
that the IRS could take the position that the Voting Rights,  the
Exchange  Right  and  the Call Rights have greater  than  nominal
value and that the transfer or receipt of such rights is taxable.
In  such event, the receipt of the Voting Rights and the Exchange
Right  and  the  conveyance  of the Call  Rights  could  generate
taxable gain or loss.  Such gain or loss would generally be  U.S.
source  short-term capital gain or loss, unless the IRS  were  to
assert  that  the Voting Rights and the Exchange  Right  (or  any
other  rights,  such as the rights beneficially enjoyed  by  U.S.
Holders under the Support Agreement) were transferred to the U.S.
Holder by MDA, and not by Orbital, in consideration for a portion
of  the U.S. Holder's MDA Common Shares.  In the latter case, any
gain  recognized  by  a U.S. Holder may be  treated  as  ordinary
income.

Distributions  on the Exchangeable Shares.  MDA understands  that
Orbital  does not intend to pay dividends prior to the  Automatic
Redemption  Date, and thus, no dividends would  be  payable  with
respect  to the Exchangeable Shares.  If any such dividends  were
paid,  however,  a  U.S. Holder of Exchangeable Shares  generally
would  be required to include in gross income as ordinary  income
any  dividends paid on the Exchangeable Shares to the extent paid
out  of  the  earnings and profits of Acquisition, as  determined
under U.S. federal income tax principles.  Distributions, if any,
in  excess  of Acquisition's current or accumulated earnings  and
profits  would constitute a non-taxable return of  capital  to  a
U.S.  Holder  to  the extent of the U.S. Holder's  basis  in  the
Exchangeable Shares and would be applied against and  reduce  the
basis  in  the  Exchangeable Shares.  To  the  extent  that  such
distributions  are  in  excess of a U.S. Holder's  basis  in  the
Exchangeable  Shares, the distributions would constitute  capital
gain.   It is possible that the IRS could take the position  that
Orbital's, rather than Acquisition's, earnings and profits should
be taken into account in the foregoing calculations.

Based  on the tax position that Orbital has advised MDA  that  it
plans to take, any dividends paid on the Exchangeable Shares  out
of Acquisition's earnings and profits would be treated as foreign
source  dividend income and would generally not be  eligible  for
the   dividends   received  deduction  allowed   to   corporation
shareholders under the Code.  It is possible, however,  that  the
IRS  could  assert  that  such dividends constitute  U.S.  source
income.   Under  the  current  Canada-United  States  Income  Tax
Convention, such distributions to U.S. Holders would  be  subject
to  Canadian withholding tax at a rate of 15% irrespective of any
position that the IRS may take.  See "Canadian Federal Income Tax
Considerations  - Holders of MDA Common Shares  Not  Resident  In
Canada,"  above.  Subject to certain limitations of U.S.  federal
income  tax  law, a U.S. Holder should generally be  entitled  to
either a credit against its U.S. federal income tax liability  or
a  deduction in computing U.S. taxable income for Canadian income
taxes   withheld   from  distributions  with   respect   to   the
Exchangeable  Shares.   The  use of a  credit  may,  however,  be
limited  or precluded entirely if the U.S. Holder has  no  income
that is treated as non U.S. source income for U.S. federal income
tax purposes.

Exchange  or  Retraction of Exchangeable  Shares.   Although  the
matter  is not free from doubt, MDA and Orbital have been advised
that  there is a reasonable basis on which to conclude  that  the
exchange, retraction or redemption of the Exchangeable Shares for
Orbital Common Shares will be treated as a taxable event for U.S.
federal income tax purposes, and Orbital has advised MDA that  it
currently  intends to take this position.  If the exchange  is  a
taxable event, and the U.S. Holder receives Orbital Common Shares
from Orbital pursuant to the Call Rights:

(1)  a  U.S. Holder generally would recognize gain or loss  equal
     to  the  difference  between the fair market  value  of  the
     Orbital  Common Shares at the time of the exchange (together
     with cash equal to the Dividend Amount (if any) and cash  in
     lieu  of  fractional shares (if any)) and the U.S.  Holder's
     tax basis in the Exchangeable Shares;

(2)  such  gain or loss would generally be capital gain or  loss,
     except  that  the  IRS  could  assert  that  a  holder  must
     recognize  amounts attributable to any declared  but  unpaid
     dividends on the Exchangeable Shares as ordinary income that
     may he treated as U.S. source income;

(3)  any capital gain or loss would be long-term capital gain  or
     loss if the Exchangeable Shares have been held for more than
     one year at the time of the exchange and otherwise would  be
     short-term capital gain or loss;

(4)  the  U.S. Holder would take as its tax basis in the  Orbital
     Common  Shares  the fair market value of the Orbital  Common
     Shares at the time of the exchange;

(5)  the holding period of the Orbital Common Shares received  by
     the U.S. Holder in exchange would begin on the day after the
     U.S. Holder receives the Orbital Common Shares; and

(6)  gain  realized  on the exchange of Exchangeable  Shares  for
     Orbital  Common  Shares generally will be  treated  as  U.S.
     source gain.

If  the  receipt of Orbital Common Shares is effected  through  a
retraction  or redemption of Exchangeable Shares with respect  to
which  Orbital does not exercise its overriding Call  Right,  and
thus  the Orbital Common Shares are distributed to a U.S.  Holder
directly by Acquisition, then if the retraction or redemption  is
treated as a taxable transaction, it will be treated as a taxable
exchange  of  the Exchangeable Shares (treated for  U.S.  federal
income  tax  purposes as described above) if the  retraction  (i)
results  in  a "complete termination" of the U.S. Holder's  stock
interest in Acquisition under section 302(b)(3) of the Code, (ii)
is  "substantially  disproportionate" with respect  to  the  U.S.
Holder  under  section 302(b)(2) of the Code, or  (iii)  is  "not
essentially  equivalent to a dividend" with respect to  the  U.S.
Holder  under  section  302(b)(1) of the  Code.   In  determining
whether  any  of  these  tests has  been  met,  shares  of  stock
considered  to be owned by the U.S. Holder by reason  of  certain
constructive  ownership rules set forth in  section  318  of  the
Code,  as well as shares actually owned, generally must be  taken
into  account.  If a retraction or a redemption is treated  as  a
taxable  transaction but does not meet any of the tests described
above,  the cash and the fair market value of the Orbital  Common
Shares received by the U.S. Holder would generally be taxed as  a
dividend  paid  on  the  Exchangeable  Share  to  the  extent  of
Acquisition's  (or,  possibly, Orbital's) earnings  and  profits.
See "Distributions on the Exchangeable Shares," above.

Irrespective of how the retraction or redemption is  treated  for
U.S. federal income tax purposes, it will, as discussed above, be
subject  to  Canadian  withholding tax.   See  "Canadian  Federal
Income  Tax  Considerations - Holders of MDA  Common  Shares  Not
Resident  in  Canada," above.  Any Canadian tax  imposed  on  the
exchange  will  be  available as a credit  against  U.S.  federal
income  taxes, subject to applicable limitations.   For  example,
the use of such a credit may be limited or precluded entirely  if
the  U.S. Holder has no income that is treated as non U.S. source
income  for  U.S. federal tax purposes.  A U.S.  Holder  that  is
ineligible for a foreign tax credit with respect to any  Canadian
tax  paid,  or  who otherwise so chooses, may be  entitled  to  a
deduction therefor in computing U.S. taxable income.

It  is possible that the exchange, or retraction or redemption of
Exchangeable Common Shares for Orbital shares would  be  held  to
constitute a nonrecognition event.  In such case:

(1)  a  U.S.  Holder that exchanges its Exchangeable  Shares  for
     Orbital Common Shares generally would not recognize gain  or
     loss on the receipt of the Orbital Common Shares;

(2)  a  U.S. Holder would, however be required to recognize  gain
     to  the  extent of the receipt of cash in lieu of fractional
     shares (if any) exceeds the tax basis allocable thereto  and
     income (which may be ordinary income) to the extent of  cash
     equal to the Dividend Amount (if any);

(3)  the tax basis of the Orbital Common Shares would be equal to
     the  tax basis of the Exchangeable Shares exchanged therefor
     (reduced  by  the  tax basis allocated to  fractional  share
     interests); and

(4)  the  holding  period  of  the Orbital  Common  Shares  would
     include  the  holding  period  of  the  Exchangeable  Shares
     exchanged therefor.

Dissenting U.S. Holders.  A U.S. Holder who exercises  its  right
to  dissent  from the Arrangement will generally  recognize  U.S.
gain or loss on the exchange of its MDA Common Shares for cash in
an  amount  equal to the difference between the  amount  of  cash
received  and  its adjusted tax basis in the MDA  Common  Shares.
Such  gain  or loss will be capital gain or loss if  such  shares
have been held for more than one year at the time of the exchange
and  otherwise will be short-term capital gain or loss, and  will
generally be U.S. source.

Shareholders Not Resident in or Citizens of the United States

The  following  summary is applicable to a holder of  MDA  Common
Shares that is not a U.S. Holder ("non-U.S. Holder").

A  non-U.S. Holder generally will not be subject to U.S.  federal
income  tax on gain recognized on the receipt of the Exchangeable
Shares, the Voting Rights and the Exchange Right, on the sale  or
exchange of the Exchangeable Shares, or on the receipt or sale of
the  Orbital  Common  Shares  unless  such  gain  is  effectively
connected with the conduct by the non-U.S. Holder of a U.S. trade
or  business  or,  if  a  tax treaty  applies,  if  the  gain  is
attributable  to a U.S. permanent establishment of  the  non-U.S.
Holder.

If  gain  recognized by a non-U.S. Holder on the receipt  of  the
Exchangeable  Shares, on the sale or exchange of the Exchangeable
Shares,  or on the receipt or sale of the Orbital Common  Shares,
is  effectively  connected with a U.S. trade or  business  or  is
attributable  to a permanent establishment in the United  States,
the  non-U.S. Holder would be subject to U.S. federal income  tax
at  the  graduated  rates that are applicable to  U.S.  citizens,
resident aliens, and domestic corporations, and may be subject to
withholding  in certain circumstances.  Non-U.S. Holders  may  be
entitled  to  a  limited foreign tax credit  on  non-U.S.  source
income  that  is  effectively connected  with  a  U.S.  trade  or
business.   In addition, if the non-U.S. Holder is a corporation,
the branch profits tax also may apply.

MDA  understands  that Orbital does not intend to  pay  dividends
prior  to  the  Automatic Redemption Date and thus, no  dividends
would  be  payable with respect to the Exchangeable Shares.   Any
dividends  received  by a non-U.S. Holder  with  respect  to  the
Exchangeable  Shares  should not be subject to  U.S.  withholding
tax,  and  MDA  understands  that  it  is  not  anticipated  that
Acquisition  would withhold any amounts in respect  of  such  tax
from  such dividends.  The possibility exists, however, that  the
IRS  may assert that U.S. withholding tax is payable with respect
to dividends paid on the Exchangeable Shares to non-U.S. Holders.
In  such case, holders of Exchangeable Shares could be subject to
U.S.  withholding tax at a rate of 30%, which rate may be reduced
by  an  applicable income tax treaty in effect between the United
States  and  the non-U.S. Holder's country of residence  (15%  on
dividends paid to residents of Canada).  Dividends paid to a non-
U.S. Holder that are effectively connected with the conduct of  a
trade or business in the United States are taxed at the graduated
rates that are applicable to U.S. citizens, resident aliens,  and
domestic corporations, and are not subject to withholding if  the
non-U.S. holder gives an appropriate statement to the withholding
agent  in  advance  of  the dividend payment.   Such  effectively
connected  dividends  also may, under certain  circumstances,  be
subject  to  an  additional branch profits tax  if  the  non-U.S.
Holder is a corporation.

Dividends  received  by a non-U.S. Holder  with  respect  to  the
Orbital   Common  Shares  generally  will  be  subject  to   U.S.
withholding  tax at a rate of 30%, which rate may be  subject  to
reduction  by  an applicable income tax treaty (15% on  dividends
paid  to  residents of Canada).  If the dividends are effectively
connected  with  the conduct of a U.S. trade  or  business,  they
would be taxed at the graduated rates that are applicable to U.S.
citizens,  resident aliens, and domestic corporations, and  would
not  be  subject to withholding if the non-U.S. holder  gives  an
appropriate statement to the withholding agent in advance of  the
dividend  payment.  A non-U.S. Holder that is a corporation  also
may be subject to an additional branch profits tax on effectively
connected dividends.

The Orbital Common Shares (and, possibly, the Exchangeable Shares
or  a portion thereof) will be deemed to be U.S. situs assets for
purposes of the U.S. federal estate tax with the result that  any
such shares held by an individual non-U.S. Holder at the time  of
his  or her death will be subject to the U.S. federal estate tax,
except  as may otherwise be provided by an applicable estate  tax
treaty with the U.S.

Information, Reporting and Backup Withholding

Information reporting to the IRS by paying agents and  custodians
located  in  the  United States may be required with  respect  to
amounts  received  on the disposition of Exchangeable  Shares  or
Orbital  Common  Shares,  or dividends  paid  on  either  of  the
foregoing.  A U.S. Holder may be subject to backup withholding at
the  rate  of 31% with respect to dividends paid by such persons,
unless  the  holder (i) is a corporation or comes within  certain
other  exempt  categories and, when required,  demonstrates  this
fact,   or  (ii)  provides  a  taxpayer  identification   number,
certifies as to no loss of exemption from backup withholding, and
otherwise  complies with applicable requirements  of  the  backup
withholding rules.  Generally, dividends paid to non-U.S. Holders
of  the  Orbital Common Shares that are subject to  the  30%  (or
reduced  treaty)  rate of withholding tax  will  be  exempt  from
backup  withholding tax.  Backup withholding is not an additional
tax, and may be credited against the holder's federal income  tax
liability.


               INFORMATION CONCERNING ACQUISITION

Acquisition  was incorporated under the CBCA on August  11,  1995
solely for the purpose of entering into the Combination Agreement
and  completing the transactions contemplated thereby,  including
the  Arrangement.  Acquisition has not carried  on  any  material
business  or  activities  other  than  those  relating   to   the
Combination  Agreement and the Arrangement.  The  registered  and
principal office of Acquisition is located at 44th Floor, 1 First
Canadian  Place,  Toronto, Ontario, M5X 1B1.  It  is  anticipated
that  immediately  prior to the Effective Date, Acquisition  will
change  its  registered and principal office  to  13800  Commerce
Parkway, Richmond, British Columbia, V6V 2J3.

Acquisition is a wholly owned subsidiary of Orbital.  Pursuant to
the Arrangement, among other things, the authorized share capital
of  Acquisition will be amended to authorize an unlimited  number
of Exchangeable Shares and 10,000 Class B Preferred Shares; as  a
result of this amendment, Acquisition will have three classes  of
authorized  share  capital consisting of an unlimited  number  of
common  shares,  an unlimited number of Exchangeable  Shares  and
10,000  Class  B Preferred Shares.  Pursuant to the  Arrangement,
the Exchangeable Shares will be issued to MDA Shareholders (other
than  Dissenting  MDA  Shareholders) and  holders  of  shares  of
Qualifying Holdcos in exchange for the MDA Common Shares held  by
them or the Qualifying Holdcos, as the case may be.  As a result,
Acquisition will become the sole shareholder of MDA.  The  10,000
Class B Preferred Shares will be issued to Canadian Imperial Bank
of  Commerce  as partial payment for investment banking  services
rendered with respect to the Arrangement.  All of the issued  and
outstanding common shares of Acquisition will be held by Orbital.
In addition, pursuant to the Arrangement, the name of Acquisition
will  be changed to "MacDonald Dettwiler Holdings Inc."  See "The
Arrangement and The Combination Agreement - Plan of Arrangement."

The directors of Acquisition are David W. Thompson (President and
Chief   Executive  Officer  of  Orbital),  Ian  J.  Cowan  (Vice-
President, Lehman Brothers Canada Inc.) and Michael Gregory (Vice-
President,  Lehman  Brothers  Canada  Inc.).   The  officers   of
Acquisition  are  David  W.  Thompson,  President,   Carlton   B.
Crenshaw,  Vice-President and Treasurer, and  Leslie  C.  Seeman,
Secretary, all of whom are also officers of Orbital.


                 INFORMATION CONCERNING ORBITAL

Background and Recent Acquisitions

Orbital  was incorporated under the laws of the State of Delaware
in   1987.   Its  headquarters  are  located  at  21700  Atlantic
Boulevard, Dulles, Virginia, 20166, U.S.A.

Orbital is a space technology company that designs, manufactures,
operates and markets a broad range of space products and services
that are grouped into three categories: Launch Systems, Space and
Electronics Systems, and Communications and Information  Systems.
Launch  Systems  include  space and suborbital  launch  vehicles;
Space  and  Electronics  Systems include  satellites,  spacecraft
platforms, space sensors and instruments, and space payloads  and
experiments,  as  well as advanced avionics and  data  management
systems;  and  Communications  and  Information  Systems  include
satellite-based  two-way  mobile  data  communications   systems,
satellite-based  navigation products and remote sensing  systems,
along   with   satellite  tracking  systems   and   environmental
monitoring products.

Orbital's  goal  is  to become a full-service  space  company  by
integrating  its launch vehicles, satellites and  other  products
into  complete "turn-key" space systems and providing  end-to-end
satellite-based  services  for  particular  markets.    Orbital's
strategy  is  to  exploit  expanding  opportunities  to   provide
government,  commercial and other customers with low-cost  access
to  and  operations  in space.  Essential elements  of  Orbital's
strategy include investment of substantial private capital in the
development  of  proprietary  products;  reduction  of  the  time
required for product development; formation of strategic business
alliances    to    enhance   Orbital's   marketing,    technical,
manufacturing  and financial capabilities; and  establishment  of
vertically integrated manufacturing and testing capabilities.  In
addition, Orbital believes that its strategy of providing  "turn-
key"  space systems, through the integration of lower-cost  space
launch  vehicles with lower-cost smaller satellites  and  sensors
and  instruments, should stimulate the use of space products  and
services   by  private  corporations,  educational  and  research
institutions and other non-traditional space customers including,
ultimately, individual consumers.

An  important  element  of Orbital's strategy  to  integrate  its
various  products  into  complete  "turn-key"  systems   is   the
acquisition  of companies with product lines that  complement  or
enhance  Orbital's  existing  base of  products,  technology  and
services.  Orbital acquired Space Data Corporation ("Space Data")
in  1988, thereby expanding its product lines and increasing  its
vertical  integration  in production and testing.   In  September
1993,  Orbital  acquired all the assets of the  Applied  Sciences
Operation,  a  division of The Perkin-Elmer Corporation  ("ASO").
This  operation  designs,  develops and produces  satellite-borne
scientific sensors for space and terrestrial research and in situ
atmospheric monitoring equipment for human space flight programs.
In  August  1994  and  December 1994, Orbital acquired  Fairchild
Space   and   Defense  Corporation  ("Fairchild")  and   Magellan
Corporation    ("Magellan"),   respectively.     The    Fairchild
acquisition has enhanced Orbital's satellite system and subsystem
development   and  production  capabilities  and   has   expanded
Orbital's  existing product lines by adding various sophisticated
electronics and defence products.  Magellan designs, manufactures
and  markets  hand-held receivers for Global  Positioning  System
("GPS") satellite-based navigation and positioning for commercial
and consumer markets.

Orbital's    customer   base   includes   a   wide    range    of
U.S.   governmental   agencies,   universities   and   commercial
enterprises  including NASA; the National Oceanic and Atmospheric
Administration; various organizations within the U.S.  Department
of  Defense ("DoD") including the U.S. Army, the U.S.  Navy,  the
U.S.  Air  Force,  ARPA  and BMDO; ORBCOMM Global;  John  Hopkins
University;   and   certain  distributors  of   electronics   and
recreational    equipment.    Orbital's    diversification    and
integration of space-based products and services is reflected  in
its  revenue  mix  with  34%, 40% and 26% of  its  1994  revenues
derived  from Launch Systems, Space and Electronics  Systems  and
Communications  and  Information Systems, respectively.   Orbital
had  revenues of approximately US$222 million for the year  ended
December 31, 1994.  As of June 30, 1995, Orbital's total backlog,
including  firm  orders  of  approximately  US$495  million,  was
approximately US$1.3 billion.

Orbital  has three wholly owned active subsidiaries --  Magellan,
ORBIMAGE  and  Fairchild  -- and owns 99.9%  of  the  outstanding
shares of ORBCOMM.  Magellan, ORBIMAGE, Fairchild and ORBCOMM are
each incorporated under the laws of the State of Delaware.

Description Of Orbital's Products And Services

The  space products and services provided by Orbital are  grouped
into  three  categories: Launch Systems,  Space  and  Electronics
Systems, and Communications and Information Systems.

Launch Systems

Orbital's  Launch  Systems  Group's products  include  space  and
suborbital  launch vehicles.  Orbital also continues  to  explore
new,  longer-term research and development opportunities for more
affordable and flexible space launch vehicles, such as  the  X-34
reusable launch vehicle described below.

Space  Launch  Vehicles.   A  space  launch  vehicle  launches  a
satellite  into  orbit around the Earth.  Orbital's  three  space
launch  vehicles are the Pegasus launch vehicle, the  Pegasus  XL
launch vehicle, and the Taurus launch vehicle.

Orbital's  Pegasus  vehicle is launched from beneath  a  modified
large  aircraft, such as a Lockheed L-1011, to deploy  satellites
up  to  1,000 pounds into low-Earth orbit.  Customers for Pegasus
include the U.S. Air Force, NASA, BMDO, ORBCOMM Global and  ARPA,
as  well  as  the Brazilian and Spanish space agencies.   Through
September  1995, Orbital has conducted a total of seven  standard
Pegasus   missions,  all  of  which  were  fully   or   partially
successful.   Whether a mission is fully or partially  successful
depends on the particular mission requirements designated by  the
customer.   The modified Pegasus XL, developed to deploy  heavier
satellites  into  orbit,  has had two unsuccessful  flights,  one
occurring  in  June 1994 and the other occurring  in  June  1995.
Orbital  believes that it correctly identified and  remedied  the
cause  of  the 1994 failure.  Orbital believes it has  identified
the  cause  of  the 1995 failure, which was not  related  to  the
anomalies  observed  in  the first unsuccessful  flight,  and  is
implementing  what  it  believes to be the  necessary  corrective
actions.  There can be no assurance, however, that the causes  of
the failures here been correctly identified or that they will  be
successfully corrected.  In 1992, Orbital entered into a ten-year
lease for a Lockheed L-1011 aircraft, which has been modified  to
enable  it  to  launch both the Pegasus and Pegasus XL  vehicles.
There  is  no  assurance that, in the event that the L-1011  were
unavailable for any reason, another aircraft could be obtained on
a timely or cost-effective basis.

The  higher-capacity  Taurus vehicle  is  a  four-stage,  ground-
launched  derivative  of  the  Pegasus  vehicle  that  can  carry
payloads  weighing  up  to 3,000 pounds to  low-Earth  orbit  and
payloads  weighing  up  to  800 pounds to  geosynchronous  orbit.
Taurus  is  designed  to  be  readily transported  with  a  self-
contained   launch   pad,  including  assembly   and   pre-flight
equipment, so that launch from a variety of developed  or  remote
locations  can  be  achieved on short  notice.   In  March  1994,
Orbital successfully launched the first Taurus vehicle, deploying
two satellites for ARPA.

Suborbital  Launch  Vehicles.  Suborbital launch  vehicles  place
payloads into a variety of high-altitude trajectories but, unlike
space  launch  vehicles, do not place payloads into orbit  around
the   Earth.    Orbital's  suborbital  launch  products   include
suborbital  vehicles  and  their principal  subsystems,  payloads
carried   by   such   vehicles,  and   related   launch   support
installations  and systems used in their assembly and  operation.
Orbital  offers  its  customers customized  vehicle  and  payload
design, manufacturing and integration, launch and mission support
and  tracking and recovery services, as well as construction  and
activation  of  launch  pads and other  infrastructure  elements.
Customers  typically use Orbital's suborbital launch vehicles  to
launch  scientific  and  other payloads and  for  defence-related
applications such as target and interceptor experiments for anti-
missile  defence  systems.  The primary customers  for  Orbital's
suborbital launch vehicles include the U.S. Army, the  U.S.  Navy
and BMDO.

From January 1991 through September 1995, Orbital has conducted a
total  of  38 launches of suborbital vehicles, of which  34  have
been  fully or partially successful and four have been  failures.
While  cutbacks  in  the DoD's budget and, in  particular,  those
projects  related to missile defence have resulted  in  decreased
revenues  attributable to suborbital launches,  Orbital  believes
that  increasing sophistication of missile technology and  public
concern  over  the  United States' missile  defence  system  will
continue   to  provide  opportunities  for  Orbital's  suborbital
program.

Reusable  Launch Vehicles.  A major reason for the high  cost  of
access  to  space today using expendable launch vehicles  is  the
fact   that   the  entire  launch  vehicle,  including  expensive
structures and electronics equipment, is expended during  launch.
Orbital  is  currently  developing the  X-34  partially  reusable
launch  vehicle with the goal of significantly reducing the  cost
of  access to space.  Like Pegasus, the X-34 will be air-launched
from  a carrier aircraft.  Although the X-34 upper stage will  be
expended during launch, the booster vehicle itself will return to
Earth, to be refurbished and reused in subsequent launches.   The
X-34  is  being  designed  to launch  small  500  to  1,000-pound
satellites to low-Earth orbit.

In  March 1995, Orbital entered into a Cooperative Agreement with
NASA  to  develop, construct, test and launch two  X-34  reusable
launch   vehicles.    At   that  time,   Orbital   and   Rockwell
International  Corporation ("Rockwell")  agreed  to  establish  a
joint  venture,  to be called American Space Lines  ("ASL"),  the
terms of which are under negotiation, to develop, construct, test
and  operate two X-34 small reusable launch vehicles.  Under  the
ASL  joint venture, Orbital will be the prime contractor for  the
design and construction of the launch vehicle, and Rockwell  will
be  a  subcontractor for the design and construction  of  various
subsystems,  including  the  propulsion  and  thermal  protection
subsystems.  There can be no assurance that Orbital and  Rockwell
will successfully conclude their negotiations to establish ASL.

Orbital  estimates that the development, construction and initial
testing  of  the  first two X-34 vehicles will  require  a  total
investment  of  at least US$190 million.  Under  the  Cooperative
Agreement  between Orbital (to be novated to ASL) and NASA,  NASA
will  partially fund the project by providing approximately US$60
million  in  cash to ASL as specified performance milestones  are
met.   NASA  also  is providing approximately  US$10  million  in
funding   NASA  centres  that  will  perform  as  subcontractors.
Orbital and Rockwell are expected to fund the remaining costs  of
the X-34 program.

The Cooperative Agreement can be suspended or revoked by NASA  or
Orbital/ASL at any time, and there can be no assurance that  NASA
will  continue  to  fund  or support the project  to  the  extent
presently contemplated by the Cooperative Agreement.  Development
and  construction of the X-34 is in a very early  stage  and  the
actual  cost  of  the  X-34  and  the  amount  and  structure  of
anticipated investment in ASL may vary significantly from current
estimates.  There can be no assurance that the funds expected  to
be  committed by Orbital, Rockwell and NASA will be sufficient to
finance  the  project,  or that ASL will be  able  to  raise  the
required capital if NASA exercises its right to suspend or revoke
the  Cooperative  Agreement.  In the  event  that  ASL  does  not
receive the necessary capital and Orbital and Rockwell decide not
to  go  forward  with the project, Orbital could be  required  to
expense part or all of its expected investment in ASL.

Space and Electronics Systems

Orbital's Space and Electronics Systems Group's products  include
spacecraft systems and payloads, defence avionics and sensors.

The  Space and Electronics Systems Group is responsible  for  the
design,  production  and  testing  of  small  and  medium   class
spacecraft  for scientific, military and commercial applications.
The  small  standard spacecraft platforms developed  by  Orbital,
such  as  the  PegaStar and the MicroStar,  are  designed  to  be
launched  by the Pegasus or Taurus launch vehicle.  The  PegaStar
spacecraft  platform  is a general purpose  spacecraft  that  has
successfully  performed  one  mission  for  the  U.S.  Air  Force
measuring  space radiation.  It is also planned to  be  used  for
Orbital's   SeaStar  ocean  environmental  monitoring   satellite
system.  Orbital's MicroStar spacecraft platform is designed  for
use  in the ORBCOMM System and also for a variety of small  space
science  and  remote sensing projects, including  some  of  those
being pursued by Orbital's wholly owned subsidiary, ORBIMAGE.  In
April  1995, the first three MicroStar spacecraft were  deployed,
two  for  the ORBCOMM System, and the other to monitor  lightning
and severe weather patterns for NASA.

Orbital's medium class satellites, such as TOPEX/Poseidon, NASA's
Upper Atmosphere Research Satellite, Landsat 4 and Landsat 5 have
been  in  space for several years, and are used to gather various
scientific data, such as ocean topography and ultraviolet sources
outside  the  galaxy.  In August 1995, Orbital  was  selected  to
become the spacecraft supplier to Johns Hopkins University, which
is  leading  NASA's Far Ultraviolet Spectroscopy Explorer  (FUSE)
program   to  measure  far  ultraviolet  radiation.    The   FUSE
spacecraft is presently scheduled for launch in 1998.

Orbital  develops,  manufactures and markets  avionics,  advanced
electronics  and  data  management systems  for  aircraft  flight
operations  and  ground support.  These systems collect,  process
and  store mission-critical data for, among other things, mission
planning and flight operations, and manage on-board equipment for
strategic tactical military aircraft, helicopters, satellites and
surface  vehicles.   The primary customers  for  data  management
systems are the U.S. Navy, the U.S. Air Force, various DoD  prime
contractors  and  foreign governments.  Orbital  is  the  leading
supplier  of  certain  avionics systems and  products,  including
mission  data  loaders  for  the U.S.  Navy,  and  data  transfer
equipment and digital terrain systems for the U.S. Air Force.  In
addition,  Orbital provides stores management systems,  including
weapons  arming and firing functions for use on tactical aircraft
and  helicopters.  The avionics systems and products are deployed
on a number of aircraft, including the F-14, F-15, F-16, F-22 and
the LAMPS Helicopter.

Orbital's  satellite-borne  scientific  sensors  and  instruments
include    atmospheric   ozone   monitoring    instruments    and
environmental  sensors.   The  Total Ozone  Mapping  Spectrometer
("TOMS") instrument was produced by Orbital to be launched  on  a
Pegasus vehicle for NASA.  TOMS will measure ozone concentrations
around the world for the purpose of monitoring the effect of man-
made chemicals and atmospheric conditions on the ozone layer.  In
addition,  Orbital is currently developing and producing  various
in  situ  monitoring products for space and defence applications.
These  products  include  the Atmospheric Composition  Monitoring
Assembly,  being  developed  under a  contract  with  The  Boeing
Company,  that  will  measure various atmospheric  gases  in  the
crew's  living quarters on the Space Station for the  purpose  of
ensuring  a  healthy living environment for astronauts.   Orbital
also  produces the Central Atmospheric Monitoring System for  the
U.S. Navy for use on submarines.

Communications and Information Systems

Orbital's Communications and Information Systems include  planned
and  operational  products  and services  provided  by  Orbital's
Magellan,   ORBCOMM   and   ORBIMAGE   subsidiaries.     Magellan
manufactures  GPS  satellite-based  navigation  and   positioning
products for commercial and consumer markets including marine and
aviation applications, outdoor recreational users such as hunters
and  hikers,  professional users such as geologists, geographers,
surveyors, natural resource managers and contractors  and,  to  a
lesser  extent,  the U.S. Government.  ORBCOMM and  ORBIMAGE  are
developing  satellite-based services  to  address  the  expanding
market  for  global two-way data communications  and  information
derived  from remote sensing of the atmosphere, oceans  and  land
surfaces.  Orbital believes that the ORBCOMM and ORBIMAGE systems
will  require significant capital investments.  Although  Orbital
believes   the   long-term  profit  potential  of  such   service
businesses  developed  and  supported  by  Orbital's  proprietary
product  technologies is significant, there can be  no  assurance
that   Orbital  will  be  able  to  successfully  develop   these
businesses.

Satellite-Based  Navigation and Positioning Products.   Orbital's
Magellan  subsidiary designs, manufactures and markets  hand-held
GPS  receivers  that provide users with precise  positioning  and
navigation  information  for  a  broad  range  of  personal   and
professional  activities  including  marine  navigation,  outdoor
recreation (hiking and hunting), surveying and general  aviation.
Magellan  focuses its research, design and engineering activities
on  the development of GPS receivers that are reliable, portable,
easy-to-use  and  affordable,  recently  targeting  the   growing
recreational  market.   Magellan  is  also  expected  to   be   a
significant  supplier of personal communicators for  the  ORBCOMM
System.

In   addition,  Orbital's  Germantown  operations  produce   data
management  systems  that  have  been  applied  to  the   design,
development   and  manufacture  of  "intelligent   transportation
systems,"  primarily  for  metropolitan transit  operators,  that
provide   GPS-based   location  of   vehicles   and   allow   for
communications and schedule management.

ORBCOMM  System.   The  ORBCOMM System  is  designed  to  provide
virtually  continuous  mobile data communications  coverage  over
much of the Earth's surface.  Under this design, subscribers will
be  able  to use inexpensive, pocket-sized personal communicators
to  send  and receive short messages, emergency alerts and  other
critical   information,  and  to  use  the   position-determining
capability  of  the communicators to obtain data  concerning  the
location  and condition of automobiles, trucks, shipping  vessels
and  other valuable assets.  Orbital expects that the ability  to
send  and  receive  other short messages  and  data  without  the
geographic  limitations  of existing data communications  systems
will stimulate the growth of new markets for satellite-based data
communications  and  will  be  used  to  supplement   terrestrial
communications systems by providing relatively low-cost  coverage
in areas outside the range of these systems.

The  ORBCOMM System design consists of a constellation  of  small
low-Earth  orbit satellites, a satellite control centre operating
and   positioning   the  satellites,  network   control   centres
controlling  the  flow of information through the  system,  local
ground stations sending and receiving signals between the network
control   centres   and  nearby  satellites,   and   the   mobile
communicators  used  by  subscribers  to  transmit  and   receive
messages  to and from nearby satellites.  In April 1995,  Orbital
successfully launched the first two satellites that will comprise
the  ORBCOMM System constellation.  After working through certain
anomalies  that were initially observed on these two  spacecraft,
the  satellites have validated a number of technical capabilities
of  the ORBCOMM System.  ORBCOMM Global is presently involving in
beta  testing the ORBCOMM System, and has successfully  used  the
ORBCOMM System to transmit data messages.

Orbital   expects  that,  using  at  least  26   satellites   and
appropriately located gateway Earth stations, the ORBCOMM  System
will provide communications availability generally exceeding  95%
during  each  24-hour  period  in the  United  States  and  other
temperate  zones  in  the Northern and Southern  hemispheres  and
exceeding  75%  of each 24-hour period in the equatorial  region.
Equatorial  region  availability could be improved  to  generally
exceed 90% with an additional plane of eight satellites.  Outages
will  be  dispersed in brief intervals over the  24-hour  period,
thereby  minimizing  the  effect of  any  unavailability  of  the
system.  The ORBCOMM System will only be available in areas where
appropriate licenses have been obtained and generally only  where
there  is  a proximate gateway Earth station and network  control
centre.

The  ORBCOMM System is being constructed and implemented  in  two
phases:   the ORBCOMM Phase 1 System, consisting of the satellite
control  centre, the United States network control  centre,  four
United   States   gateway  Earth  Stations  and   two   MicroStar
satellites; and the ORBCOMM Phase 2 System, consisting of  up  to
an  additional  34  MicroStar satellites.  The  ORBCOMM  Phase  1
System  satellites were launched in April 1995, and Phase  1  has
been  substantially completed.  Subject to the ability of ORBCOMM
Global to secure sufficient financing and completion of satellite
development and production in accordance with current  schedules,
Orbital  believes that the ORBCOMM Phase 2 System could be  fully
operational in late 1997.

Development and Financing.  Effective June 30, 1993, ORBCOMM  and
Teleglobe  Mobile formed a partnership, ORBCOMM Global,  for  the
design, development, construction, testing and operation  of  the
ORBCOMM  System, and formed two marketing partnerships to  market
the  ORBCOMM  System  in the United States  and  internationally.
ORBCOMM  USA,  L.P.  ("ORBCOMM USA")  and  ORBCOMM  International
Partners,  L.P.  ("ORBCOMM International,  "  and  together  with
ORBCOMM USA, the "Marketing Partnerships") each has the exclusive
right  to  market  the ORBCOMM System in the  United  States  and
internationally,  respectively.  Also effective  June  30,  1993,
Orbital  entered  into  an arm's length  agreement  with  ORBCOMM
Global  pursuant  to  which Orbital had  responsibility  for  the
overall design, development and integration of the ORBCOMM System
(the  "System Agreement").  The System Agreement was replaced  by
the  ORBCOMM System Procurement Agreement between ORBCOMM  Global
and   Orbital,   dated  September  12,  1995  (the   "Procurement
Agreement").

The  Phase  1  System was designed, constructed  and  implemented
pursuant  to  the  System Agreement.  The  Procurement  Agreement
provides  that  Orbital will, among other things,  construct  and
launch  24 satellites, and construct an additional 10 satellites,
for the ORBCOMM Phase 2 System.  Under the Procurement Agreement,
Orbital  is  providing  satellites and launch  services  and  the
remaining  work  to be done on the U.S. satellite control  centre
and U.S. gateway Earth stations on a fixed-price basis.

Construction and implementation of the ORBCOMM Phase 1 System  in
the   United  States  cost  approximately  US$65  million,   with
US$55  million and US$10 million contributed by Orbital  (through
ORBCOMM)  and  Teleglobe Mobile, respectively.  Teleglobe  Mobile
and  Orbital (through ORBCOMM) are obligated to increase each  of
their aggregate investment in ORBCOMM Global to US$85 million and
US$75 million, respectively.


Under  ORBCOMM  Global's  partnership agreement,  action  by  the
partnership  generally requires the approval of general  partners
holding   a  majority  of  the  participating  interests   (i.e.,
interests  participating in profits and losses). Each of  ORBCOMM
and  Teleglobe Mobile is a general partner of ORBCOMM Global  and
holds 50% of the participating interests in ORBCOMM Global,  with
the result that the approval of both Orbital and Teleglobe Mobile
is  necessary for ORBCOMM Global to act.  ORBCOMM holds  directly
and  indirectly a 51% participating interest in ORBCOMM  USA  and
Teleglobe   Mobile   holds  directly   and   indirectly   a   51%
participating interest in ORBCOMM International, with the  result
that  ORBCOMM  acting alone generally controls the  operation  of
ORBCOMM USA, and Teleglobe Mobile acting alone generally controls
the operation of ORBCOMM International.

Although   construction  of  the  ORBCOMM  Phase  1   System   is
substantially  completed, development  and  construction  of  the
ORBCOMM  Phase 2 System is in an early stage and the actual  cost
of  the  system,  schedule and the amount and  structure  of  the
anticipated  investment in ORBCOMM Global may vary  significantly
from   current   estimates.    Orbital   expects   that   design,
construction  and  implementation in the  United  States  of  the
ORBCOMM   Phase   2   System  will  require  total   capital   of
approximately  US$160  million,  bringing  the  total   estimated
required   capital  for  the  ORBCOMM  System  to   approximately
US$235  million.   ORBCOMM  Global  may  seek  additional  equity
contributions  and/or  bank  or other  debt  financing.   ORBCOMM
Global has already obtained asset-based financing of US$5 million
to  fund  a portion of its development and startup costs for  the
ORBCOMM  Phase 2 System.  Orbital has guaranteed ORBCOMM Global's
outstanding  indebtedness,  and  Orbital  or  Teleglobe  may   be
required  to  guarantee or provide credit support  in  connection
with   additional   indebtedness  incurred  by  ORBCOMM   Global.
Teleglobe  Mobile  has obtained a US$44 million  commitment  from
Technologies    Resources   Industries    Bhd.,    a    Malaysian
telecommunications  company, to acquire up to  30%  of  Teleglobe
Mobile's  interest in ORBCOMM Global.  Orbital has been  informed
that   Teleglobe   Mobile  may  seek  additional   investors   to
participate in its investment in ORBCOMM Global.

In  the event that ORBCOMM Global does not otherwise receive  the
necessary  capital, implementation and commercial development  of
the  ORBCOMM  System may be delayed, significantly restricted  or
possibly abandoned, and Orbital could be required to expense part
or  all  of  its investment in the ORBCOMM System.  In  addition,
start-up  of the ORBCOMM System will produce significant  ORBCOMM
Global  operating losses for several years.  Even if the  ORBCOMM
System  is fully implemented, there can be no assurance  that  an
adequate  market will develop for ORBCOMM System  services,  that
ORBCOMM Global will achieve profitable operations or that Orbital
will  recover  any of its past or anticipated investment  in  the
ORBCOMM System.  Because Orbital has a 50% participating interest
in  ORBCOMM  Global, Orbital expects to recognize  its  pro  rata
share of ORBCOMM Global profits and losses.

Regulatory Approvals.  In October 1994, ORBCOMM became the  first
company  to be awarded full U.S. Federal Communication Commission
("FCC")  authority to construct, launch and operate  a  low-Earth
orbit  satellite-based messaging and data communications  network
in  the  United  States.  This license, which provides  that  the
ORBCOMM System must be constructed within six years from the date
the  license was granted, extends for a period of ten years  from
the  date  the first ORBCOMM System satellite became operational.
At  the  end of the seventh year of the ten-year term, a  renewal
application  must  be filed with the FCC.  ORBCOMM  has  retained
control   over  applicable  FCC  licences  consistent  with   FCC
regulations.   As  with  any  such license,  the  ORBCOMM  System
license may be revoked and a license renewal application  may  be
denied  for  cause.  In late 1994, two other applicants  for  FCC
licenses similar to that awarded to ORBCOMM petitioned the FCC to
reconsider  the  grant  of the license to ORBCOMM.   ORBCOMM  has
opposed  the  petitions, which Orbital and  ORBCOMM  believe  are
without  merit.   In  addition, for  the  ORBCOMM  System  to  be
operated in other countries throughout the world, Orbital or  the
foreign  licensees  must  obtain  from  the  appropriate  foreign
regulatory  bodies authority to do so.  Orbital anticipates  that
the  cost of these activities will be borne primarily by  foreign
licensees.   ORBCOMM International has entered  into  preliminary
agreements  with 19 candidate licensees serving 66  countries  to
seek  such  licenses  and  to  initiate  country-specific  market
development  in  such countries.  There can be no assurance  that
Orbital  or  foreign licensees will be granted  all  licenses  or
approvals  necessary to operate the ORBCOMM System in  any  other
country.

ORBIMAGE  Remote Sensing and Imaging Systems.  Orbital, primarily
through  ORBIMAGE, is currently seeking to develop and  market  a
broad  range  of  information services to  identify  and  monitor
global environmental changes and to collect and disseminate other
remote  sensing information.  Small Earth-viewing satellites  and
related  sensors and instruments to be placed in  relatively  low
orbits  are  expected  to offer cost-efficient  data  collection,
daily  global  coverage and high-resolution imaging services  for
government and commercial uses.

In   April   1995,  ORBIMAGE's  first  MicroStar  satellite   was
successfully  launched to monitor lightning  and  severe  weather
patterns  for  NASA.   In  March 1991,  Orbital  entered  into  a
contract  with  NASA  to provide worldwide, daily  ocean  imagery
using   Orbital's  SeaStar  environmental  monitoring   satellite
system,  based  on  the PegaStar spacecraft.   Orbital  plans  to
develop,  produce,  launch  and operate  the  SeaStar  system  to
deliver high-quality multi-spectral ocean imagery for up to  five
years,  currently scheduled to commence during 1996.  In addition
to  providing  unprocessed real-time ocean data to NASA,  Orbital
plans  to process and package the data received from SeaStar  and
to  use value-added resellers and other marketing agents to  sell
the  SeaStar data to other U.S. Government users and to potential
domestic   and   international  customers  such   as   commercial
fishermen, oil and gas companies, ocean transportation  companies
and oceanographers.

ORBIMAGE  is developing and marketing other small satellite-based
Earth  observation,  remote sensing and environmental  monitoring
services  using,  among  other  things,  Orbital's  PegaStar  and
MicroStar   spacecraft  platforms,  Pegasus  and  Taurus   launch
vehicles, space sensors and instruments and other space products.
Services to be provided by ORBIMAGE could include high-resolution
optical  imaging  of  land  surfaces for  geographic  information
services,  mapping  and  news-gathering,  sensing  of  ocean  and
atmospheric  conditions and measuring of ozone and other  gaseous
concentrations   in  the  atmosphere.   ORBIMAGE   is   currently
exploring potential strategic arrangements for the development of
several remote sensing businesses, with Orbital providing  launch
services, spacecraft and other related products.  There can be no
assurance  that ORBIMAGE will be able to conclude such  strategic
arrangements  or develop profitable commercial Earth observation,
remote sensing or environmental monitoring businesses.

Satellite  Tracking Systems.  Orbital's ground tracking  systems,
installed at approximately 70 sites around the world, consist  of
meteorological and satellite tracking and telemetry stations that
are  used  to  collect weather data and to communicate  with  and
control  orbiting  spacecraft.  Orbital's current  customers  for
satellite  tracking  systems include Lockheed Martin  Corporation
("Lockheed Martin"), ORBCOMM and Orbital's SeaStar project.  As a
result  of  the Arrangement, Orbital is exploring the feasibility
of combining its satellite tracking systems operations with those
of MDA.

Competition

Orbital  believes that competition for sales of its products  and
services  is  based  on price, performance  and  other  technical
features, reliability, scheduling and customization.

The  primary  competition to the Pegasus and Taurus  vehicles  is
expected   to   come  from  the  smaller  and   larger   classes,
respectively, of LLV launch vehicles currently being developed by
Lockheed  Martin.  The LLV had an unsuccessful  first  flight  in
August 1995. Direct competition to the Taurus vehicle also  comes
from   EER   Systems'   Conestoga  launch   vehicle.    Potential
competition  to the Pegasus may come from launch systems  derived
from  surplus ballistic missiles that could be made available  by
the  U.S.  Government  and various foreign governments  including
Russia.   In  addition,  the  X-34  reusable  launch  vehicle  is
expected  to  compete with, and eventually replace, the  Pegasus.
Competition  for  Taurus could also come from  surplus  Titan  II
launch   vehicles,   although  Titan  II  production   has   been
discontinued  and  only  a limited inventory  remains.   Indirect
competition to the Pegasus and Taurus vehicles also exists in the
form  of  secondary  or  "piggyback" payload  capacity  on  large
boosters  such  as  Ariane, Titan, Long March and  Proton  launch
vehicles.   While secondary payloads offer a low-cost  method  of
launching satellites in some cases, the secondary status  of  the
payload often requires customers to accept less desirable orbits,
"standby" launch scheduling and potentially more complicated  and
costly payload integration procedures.

Orbital's  suborbital  launch vehicles,  spacecraft  systems  and
payloads,  satellite-based services and  space  support  products
compete  with  products  and services  produced  or  provided  by
numerous  companies and government entities.  Orbital's  airborne
and ground-based electronics, data management systems and defence-
oriented   avionics  products  face  competition   from   several
established   manufacturers.    Orbital's   space   sensors   and
instruments  face  competition from a  number  of  companies  and
university   research  laboratories  capable  of  designing   and
producing space instruments.

The ORBCOMM System will face direct and indirect competition from
numerous   existing   and  potential  alternative   communication
products  and  services from various large and  small  companies,
ranging  from one-way tower-based data and messaging services  to
sophisticated    two-way   satellite-based   data    and    voice
communications  services.  Depending on the  requirement  of  the
specific  market,  the ORBCOMM System may both compete  with  and
complement existing services such as one-way and two-way  paging,
cellular  data,  specialized mobile radio and  private  networks.
ORBIMAGE  may  face competition from private and U.S.  government
entities  that  provide satellite-based and other  land  imaging,
environmental  monitoring and atmospheric sensing products.   GPS
satellite-based navigation and positioning products  manufactured
by  Magellan face competition from several other producers of GPS
receivers,  such  as Garmin International and Trimble  Navigation
Ltd.  Orbital believes that Magellan's success will depend on its
ability  to  continue  to  develop new  lower-cost  and  enhanced
performance  products and to enter into and develop  new  markets
for GPS receivers.

Many  of  Orbital's competitors are larger and have substantially
greater  resources  than Orbital.  Furthermore,  the  possibility
exists  that  other domestic or foreign companies or governments,
some  with  greater experience in the space industry and  greater
financial  resources than Orbital, will seek to produce  products
or  services  that compete with those of Orbital,  including  the
Pegasus  and  Taurus launch vehicles, various  suborbital  launch
vehicles,  PegaStar, MicroStar and other satellite  systems,  GPS
receivers  and  ORBCOMM and other satellite services.   Any  such
foreign  competitor could benefit from subsidies from,  or  other
protective  measures  by,  its home  country.   In  addition,  in
response  to  reductions in the U.S. defence budget, Orbital  may
face  competition from companies, such as missile  manufacturers,
that  could attempt to adapt existing or future products for non-
defence, space or suborbital launch applications.

Research and Development

Orbital  believes that its future success will depend in part  on
its  ability to continue to conceive and develop new products and
services  and enhance existing products on a more rapid and  less
expensive  basis  than  its  competitors.   Accordingly,  Orbital
expects  to  continue to invest in product-related  research  and
development,  to conceive and develop new products and  services,
to  enhance existing products and to seek customer and  strategic
partner   investments   in  these  products.    These   strategic
relationships have included, and may include in the future, joint
development   arrangements,   joint   venture   investments   and
acquisitions of strategic product lines and businesses.

Orbital's  research  and development expenses,  excluding  direct
customer-funded  development, were approximately  US$8.8  million
for  the six months ended June 30, 1995 and approximately US$14.4
million, US$14.9 million, and US$10.6 million for the years ended
December  31,  1994,  1993  and  1992,  respectively.   Orbital's
research and development expenses during 1995 have been and  will
be  primarily  for  new  or modified launch  systems,  spacecraft
programs,  including possible ORBIMAGE projects,  and  satellite-
based navigation and positioning products.

Backlog and Contracts

Orbital's   firm  backlog  at  June  30,  1995   and   1994   was
approximately  US$495  million and US$256 million,  respectively.
As  of June 30, 1995, approximately 60% of Orbital's backlog  was
with  the  U.S. Government and its agencies or from  subcontracts
with  the  U.S. Government's prime contractors.  Backlog consists
of  aggregate contract values for firm product orders,  excluding
the  portion  previously included in operating  revenues  on  the
basis  of  percentage  of  completion accounting,  and  including
government  contracts awarded but not signed and orders  not  yet
funded  in  the  amounts of approximately US$140  million  as  of
June  30,  1995.   Approximately US$385  million  of  backlog  at
June 30, 1995 is currently scheduled to be performed beyond 1995.
Backlog excludes unexercised contract options having an aggregate
potential  contract  value  at June  30,  1995  of  approximately
US$795 million.

A  substantial portion of Orbital's revenues have been  generated
primarily  under fixed-price incentive fee, firm fixed-price  and
cost-plus-fee  U.S. government contracts.  Fixed-price  incentive
fee contracts are long-term contracts with specified cost, profit
and  price targets.  To the extent a contractor incurs less costs
than targeted, the contractor's profit will be increased based on
contractual  incentives.   In  this  manner,  the  contractor  is
encouraged to keep costs at a minimum and, as a reward,  realizes
additional  profit.   The  U.S.  Government,  by  virtue  of  the
contractor's  reduced costs, offset in part by increased  profit,
realizes a reduced price for the product or service.  Firm-fixed-
price contracts are long-term contracts with fixed stated prices.
The  contractor bears the burden of cost increases  and  realizes
the  reward  of  cost  savings.  Cost-plus-fee  contracts,  which
include    cost-reimbursable    contracts,    cost-plus-fixed-fee
contracts, cost-plus-award-fee contracts and cost-plus-incentive-
fee   contracts,  are  long-term  contracts  that   reimburse   a
contractor  for  all  costs incurred in the  performance  of  the
contract  with  various  contractual fee arrangements,  including
fixed  fees, award fees based on specific contractor performance,
and incentive fees based on contractor cost performance.

Orbital  uses the percentage of completion method of  accounting,
whereby  revenue is recognized based on actual costs incurred  in
relation  to  total estimated costs to complete the  contract  or
based  on  specific delivery terms and conditions, with incentive
and award amounts included in revenue or expense based on ongoing
estimates of expected incentive or award fees.  Unforeseen events
and  circumstances  can  alter Orbital's estimate  of  the  costs
associated with a particular contract and any related  profit  or
incentive  or award fee.  To the extent cost overruns  cannot  be
passed on to Orbital's customers, they could materially adversely
affect Orbital's results of operations.

All  of Orbital's U.S. Government contracts and, in general,  its
subcontracts   with  the  U.S.  Government's  prime  contractors,
provide that such contracts may be terminated at will by the U.S.
Government  or the prime contractor, respectively.   Furthermore,
any  of these contracts may become subject to a government-issued
stop  work  order  under  which Orbital is  required  to  suspend
production.   In the event of a termination at will,  Orbital  is
normally  entitled  to  the purchase price for  delivered  items,
reimbursement  for allowable costs for work in  process,  and  an
allowance for reasonable profit thereon or adjustment for loss if
completion of performance would have resulted in a loss.  Orbital
has experienced several contract suspensions and terminations  in
the past, and there can be no assurance that such terminations or
stop work orders will not occur in the future.

During  1994,  1993  and 1992, approximately 60%,  70%  and  80%,
respectively,  of  Orbital's total annual revenues  were  derived
from  contracts with the U.S. Government and its agencies or from
subcontracts   with  the  U.S.  Government's  prime  contractors.
Orbital's  government contracts are subject to regular audit  and
periodic  reviews  and  may be modified,  increased,  reduced  or
terminated in the event of changes in government requirements  or
policies,  Congressional appropriations and program progress  and
scheduling.   Orbital  believes that any  adjustments  likely  to
result from pending inquiries or audits of its contracts will not
have  a  material adverse impact on Orbital's financial condition
or  results of operation.  Since Orbital's inception, it has  not
experienced  any  material adjustments as a result  of  any  such
inquiries or audits.  U.S. Government curtailment of expenditures
for  space  research  and development and  related  products  and
services  could  have  a  material adverse  effect  on  Orbital's
revenues and results of operations.

Properties

In  1993,  Orbital  entered into a 12-year  lease  agreement  for
approximately 100,000 square feet of office and engineering space
in  Dulles, Virginia, which serves as its corporate headquarters.
In  1994,  Orbital  completed construction  of  an  approximately
30,000   square-foot  satellite  engineering  and   manufacturing
facility on land adjacent to the Dulles office facility.  Orbital
also   leases  approximately  320,000  square  feet  of   office,
engineering  and  manufacturing space  in  Germantown,  Maryland;
312,000  square  feet  of office, engineering  and  manufacturing
space in Chandler, Arizona; approximately 135,000 square feet  of
office,   engineering   and  manufacturing   space   in   Pomona,
California;   approximately  40,000  square   feet   of   office,
engineering and manufacturing space in San Dimas, California; and
approximately  25,000  square  feet  of  manufacturing  space  in
Mexicali,  Mexico.   Orbital  leases other  small  facilities  or
offices   in   Huntsville,  Alabama;  Edwards  Air  Force   Base,
California; Vandenberg Air Force Base, California; and Greenbelt,
Maryland.  Although completion of Orbital's existing and  pending
contracts  may  in  the  future require additional  manufacturing
capacity,  Orbital  believes  that its  existing  facilities  are
adequate for its near- and medium-term requirements.

Environmental Regulation

Orbital's  operations are subject to a variety of Federal,  state
and  local  environmental regulations, including laws  regulating
air  and  water  quality and hazardous materials and  regulations
implementing  those laws.  Orbital is one of several  potentially
responsible parties involved in a California mandated clean-up of
a  manufacturing  facility  near  Salinas,  California.   Through
June  30,  1995,  Orbital  and two other potentially  responsible
parties  have shared certain investigation and monitoring  costs,
resulting   in   total  Orbital  expenditures   after   insurance
recoveries of approximately US$85,000.  Orbital does not  believe
that   its  total  exposure  in  this  clean-up,  or  that  other
compliance by it with applicable environmental regulations,  will
have a material adverse effect on its operations.

Insurance

Orbital  maintains  a US$100 million aviation products  liability
policy that insures Orbital against certain liabilities to  third
parties  that  might arise in connection with the  production  or
operation  of  a  number of its products and generally  purchases
launch liability insurance with respect to certain liabilities to
third  parties  that  might arise in connection  with  a  launch.
Orbital  also  maintains a commercial general liability  umbrella
policy of US$50 million to insure Orbital against any third party
claims  associated  with its manufacturing or business  ventures.
In  addition, under certain of its government contracts,  Orbital
is  indemnified by the U.S. Government against certain  potential
third-party  liabilities resulting from launch  or  operation  of
space  launch vehicles and for commercial launches is indemnified
against  certain of such liabilities under launch  licenses  with
the U.S. Department of Transportation.  In circumstances in which
Orbital has provided mission success warranties, depending on  an
assessment  of its exposure and the availability and  pricing  of
insurance,  Orbital generally seeks to purchase  mission  success
insurance,  which  provides coverage  with  respect  to  contract
losses in the event its launch vehicles or other products fail to
perform  and the mission is not completed successfully.   Orbital
separately maintains both property (aircraft hull) and  liability
insurance on the Lockheed L-1011 aircraft it is currently leasing
for its Pegasus program.

Orbital  reviews  its insurance coverage from time  to  time  and
considers  changes to its insurance coverage in response  to  the
introduction  and  operation  of  new  products.   The  insurance
carried  by  Orbital and its indemnity rights  against  the  U.S.
Government  and other parties do not extend to all  of  Orbital's
products and services, may not cover all potential risks and  may
not  be effective to protect Orbital against all potential claims
or  losses.  In addition, there can be no assurance that  mission
success  insurance will be available at premium  levels  that  in
Orbital's  judgment justify purchase of such  insurance  or  that
such  insurance  will  be  available in all  instances  in  which
Orbital has provided mission success warranties.

Litigation

To its knowledge, Orbital is not a party to any legal proceeding,
the  outcome  of  which would materially impact its  business  or
operations.

Management's  Discussion and Analysis of Financial Condition  and
Results of Operations

Overview

A  significant portion of Orbital's revenues are generated  under
fixed-price  incentive fee, firm fixed-price,  and  cost-plus-fee
contracts with various agencies of the U.S. Government, including
NASA, the U.S. Air Force, ARPA, the U.S. Army, the U.S. Navy  and
BMDO.   Orbital  recognizes  revenues  using  the  percentage  of
completion  method of accounting, whereby revenue  is  recognized
based  on  actual  costs incurred in relation to total  estimated
costs  to  complete  the contract or based on  specific  delivery
terms  and conditions.  In the case of fixed-price incentive  fee
contracts, the final revenue amount can be increased or decreased
in  accordance with cost incentive provisions that measure actual
financial performance against established targets.  The incentive
fee is included in revenue at the time the amount of such fee can
reasonably  be  determined.  In the case of cost-plus  award  fee
contracts,  revenues  are  recognized  to  the  extent  of  costs
incurred plus a proportionate amount of a base fee fixed  at  the
inception of the contract, if any.  The award fee is included  in
revenue   as  work  is  performed  based  on  Orbital's  on-going
estimates of the amount of the fee to be awarded.  To the  extent
that   estimated  costs  of  completion  are  adjusted,   revenue
recognized  from  a particular contract will be affected  in  the
period of the adjustment.

Orbital is accounting for its investment in ORBCOMM Global  using
the  equity  method of accounting and will continue  to  use  the
equity  method as long as Orbital's interest in the  profits  and
losses  of  ORBCOMM Global does not exceed the current  50%.   In
accordance   with  the  equity  method  of  accounting,   Orbital
consolidates  100%  of  the revenues earned  and  costs  incurred
pursuant to the System Agreement and Procurement Agreement.   See
"Information on Orbital - Communications and Information  Systems
- -  Development and Financing."  Orbital also recognizes as equity
in  earnings (losses) of affiliates its pro rata share of ORBCOMM
Global's profits and losses.  During construction of the  ORBCOMM
System,  ORBCOMM Global is capitalizing substantially all  system
construction  costs,  including amounts  paid  under  the  System
Agreement  and  Procurement Agreement.   To  the  extent  ORBCOMM
Global  capitalizes its purchases under these agreements, Orbital
eliminates  as equity in earnings (losses) of affiliates  50%  of
Orbital's profits and losses thereunder.

Orbital  acquired Magellan on December 28, 1994, in a transaction
accounted  for  as a pooling of interests.  Orbital's  historical
financial information has been restated to effect the pooling  of
interests with Magellan as of the earliest period presented.   On
August  11,  1994, Orbital acquired Fairchild,  a  subsidiary  of
Matra  Aerospace,  Inc.,  in a transaction  accounted  for  as  a
purchase business combination.  Fairchild's results of operations
for  the  nineteen-week period ended December 31, 1994 have  been
included in Orbital's consolidated results of operations for  the
year   ended  December  31,  1994.   Orbital  acquired   ASO   on
September 17, 1993, in a transaction accounted for as a  purchase
business  combination.   ASO's  results  of  operations  for  the
fourteen-week  period ended December 31, 1993 have been  included
in  Orbital's  consolidated results of operations  for  the  year
ended December 31, 1993.

Adoption of New Accounting Standard

The  Financial  Accounting Standards Board recently  issued  SFAS
No.  121, "Accounting for the Impairment of Long-Lived Assets and
Long-Lived  Assets  to  be Disposed Of" ("SFAS  121")  which  (i)
requires that long-lived assets "to be held and used" be reviewed
for  impairment  whenever  events  or  changes  in  circumstances
indicate  that  the  carrying amount  of  an  asset  may  not  be
recoverable, (ii) requires that long-lived assets "to be disposed
of"  be  reported at the lower of carrying amount or  fair  value
less  cost  to sell, and (iii) provides guidelines and procedures
for measuring an impairment loss that are significantly different
from existing guidelines and procedures.

Orbital  adopted  the provisions of SFAS 121 during  the  quarter
ended  June 30, 1995.  As a result, as of January 1, 1995 Orbital
recorded  a  cumulative  adjustment for a  change  in  accounting
principle  of  approximately  US$4.2  million  related   to   the
impairment  in  the  carrying amount  of  certain  assets  to  be
disposed  of  that supported its orbit transfer  vehicle  product
line.

The  following table shows Orbital's revenues, gross  profit  and
gross  profit margin, by major product category, for each of  the
three years ended December 31, 1992, 1993 and 1994.

OMITTED:  See Management's Discussion and Analysis in the Company's
Annual Report on Form 10-K filed with the SEC on March 29, 1995.


Results  of Operations for the Six-Month Periods Ended  June  30,
1995 and 1994

Revenues.   Orbital's  revenues for the six-month  periods  ended
June  30,  1995  and 1994 were US$132,930,000 and  US$98,675,000,
respectively.

Space   launch   vehicle   revenues   were   US$11,965,000    and
US$29,762,000 for the six-month periods ended June 30,  1995  and
1994,  respectively.  The significant decrease in revenues during
the  periods is attributable primarily to the continuing  effects
of  production delays caused by Orbital's failed first launch  of
its  new Pegasus XL launch vehicle in June 1994, and was impacted
to  some extent by the failed second launch of the Pegasus XL  in
June 1995. Orbital expects revenues during the rest of 1995 to be
less  than 1994 as a result of the ongoing failure review process
and resulting schedule delays.  Sales of space launch vehicles to
ORBCOMM  Global were US$1,452,000 and US$4,150,000 for  the  1995
and 1994 six-month periods, respectively.

Revenues   from   suborbital   launch   vehicle   products   were
US$11,492,000  and US$11,626,000 for the six-month periods  ended
June  30, 1995 and 1994, respectively.  While suborbital revenues
have  decreased significantly during the past few years  as  U.S.
Government  defence  spending has been reduced,  Orbital  expects
1995  revenues  to remain approximately consistent  with,  or  to
increase slightly from, revenue levels achieved in 1994.

For  the  six  months  ended  June 30, 1995,  spacecraft  systems
revenues  increased  to US$28,901,000 from US$11,043,000  in  the
same period in 1994.  The increase in spacecraft system sales  is
primarily  as  a  result  of additional revenues  generated  from
Orbital's  Germantown operations, acquired in August  1994.   The
1995  and  1994  six-month  periods  included  US$3,395,000   and
US$4,496,000,  respectively, in sales of MicroStar spacecraft  to
ORBCOMM  Global.   Space  sensors  and  instruments  sales   were
US$6,547,000  and  US$8,773,000 for the 1995 and  1994  six-month
periods, respectively, and are expected to remain lower than 1994
levels throughout 1995.

Revenues  from  defence  electronics and avionics  products  were
approximately US$29,790,000 and US$5,860,000 in the 1995 and 1994
six-month periods, respectively.  Orbital acquired these products
as  part  of  the  August  1994  Fairchild  acquisition  and  the
September 1993 acquisition of ASO.

Revenues  from  sales  of  navigation  and  positioning  products
increased to US$26,459,000 for the six months ended June 30, 1995
as  compared to US$18,553,000 for the 1994 period, primarily  due
to increased unit sales offset, in part, by lower unit prices for
GPS navigators.

Revenues from Orbital's newly established Advanced Projects Group
were  US$9,404,000 during the first half of 1995 as a  result  of
work  performed under the Cooperative Agreement with NASA awarded
in  March  1995  for the development of the X-34  small  reusable
launch vehicle and work under a contract with ARPA, completed  in
April  1995,  for  the  study of a new advanced  unmanned,  long-
duration, high-flying aircraft.

Gross  Profit.   Gross  profit depends on a  number  of  factors,
including  Orbital's  mix of contract types  and  costs  incurred
thereon in relation to estimated costs.  Gross profit for the six-
month periods ended June 30, 1995 and 1994 was US$35,637,000  and
US$25,052,000, respectively.  Gross profit margin as a percentage
of  sales  was  approximately 26.8% and 25.4%, for the  six-month
periods  ended  June  30,  1995  and  1994,  respectively.    The
increased   gross  profit  margin  during  1995   was   primarily
attributable  to  increased margins for  spacecraft  systems  and
navigation  and  positioning products, offset  in  part  by  cost
increases  on the Pegasus program as a result of the  Pegasus  XL
failures  in  June of 1994 and 1995.  Orbital believes  that  its
gross  profit  margin  for the remainder of  1995  will  increase
slightly as compared to the first half of 1995.

Research  and  Development  Expenses.  Research  and  development
expenses  represent  Orbital's  self-funded  product  development
activities,   and  exclude  direct  customer-funded  development.
Research and development expenses for the 1995 and 1994 six-month
periods   were   US$8,764,000  and  US$6,506,000,   respectively.
Research and development expenses in 1995 relate primarily to the
development   of   new  or  improved  navigation   products   and
development efforts on Orbital's Pegasus XL program, and  include
estimated  expenses  related to the recent  Pegasus  XL  failure.
Orbital expects its research and development expenditures for the
rest of 1995 to be consistent with second half 1994 expenditures.

Selling,  General and Administrative Expenses.  Selling,  general
and  administrative  expenses include  the  costs  of  marketing,
advertising, promotional and other selling expenses  as  well  as
the  costs  of the finance, administrative and general management
functions   of  Orbital.   Selling,  general  and  administrative
expenses  for  the six months ended June 30, 1995 and  1994  were
US$22,707,000 (or 17.1% of revenues) and US$14,472,000 (or  14.7%
of revenues), respectively.  The increase in selling, general and
administrative  expenses  during 1995 as  compared  to  1994  was
primarily  attributable to expanded marketing efforts related  to
Orbital's  ORBCOMM project (US$3,304,000 of expenses in  1995  as
compared  to US$1,714,000 in 1994) and to various remote  sensing
systems  (US$408,000  of expenses in 1995 with  no  corresponding
expenses  in  1994), and to the August 1994 Fairchild acquisition
(US$12,188,000  of expenses in 1995).  Orbital  expects  selling,
general  and administrative expenses as a percentage of  revenues
during  the  remainder of 1995 to be less than  or  approximately
equal to those in the first half of 1995.

Interest  Income and Interest Expense.  Net interest expense  for
the  1995  six-month  period  was  US$1,887,000  as  compared  to
US$931,000 of net interest income for the 1994 six-month  period.
Interest  income  for the periods reflects interest  earnings  on
short-term  investments.   Interest  expense  is  primarily   for
outstanding  amounts on Orbital's revolving credit  facility,  on
Orbital's public debentures and, during 1995, on acquisition debt
incurred   in   connection  with  the   August   1994   Fairchild
acquisition.   Interest expense has been reduced  by  capitalized
interest  of US$2,533,000 and US$2,517,000 for the 1995 and  1994
six-month periods, respectively.

Equity  in  Earnings (Losses) of Affiliates.  Equity in  earnings
(losses)  of affiliates for the six-month periods ended June  30,
1995   and   June   30,  1994  of  US$362,000  and  (US$544,000),
respectively,  represents elimination of 50% of  the  profits  on
sales  to ORBCOMM Global, as well as Orbital's pro rata share  of
ORBCOMM Global's current period earnings and losses.  During  the
construction  phase of the project and prior to the  commencement
of   planned   operations,   ORBCOMM   Global   is   capitalizing
substantially all construction-related costs and is expensing  as
incurred all selling, general and administrative costs as  period
costs.

Provision for Income Taxes.  A provision for income taxes was not
necessary  for the six months ended June 30, 1995 given Orbital's
reported  operating  losses.   Orbital  recorded  an  income  tax
provision of US$917,000 for the six-month period ended  June  30,
1994.  Orbital records its interim income tax provisions based on
estimates  of  Orbital's  effective  tax  rate  expected  to   be
applicable  for the full fiscal year.  Estimated effective  rates
recorded  during interim periods may be periodically revised,  if
necessary, to reflect current estimates.

At December 31, 1994, Orbital had approximately US$50,000,000 and
US$900,000  of  net operating loss and tax credit  carryforwards,
respectively,  which are available to reduce  future  income  tax
obligations,  subject  to certain annual  limitations  and  other
restrictions.

Results of Operations for the Years Ended December 31, 1994, 1993
and 1992

Revenues.   Orbital's  revenues for  1994,  1993  and  1992  were
US$221,946,000, US$223,087,000 and US$204,190,000,  respectively.
Revenues in 1994 included approximately US$30 million in sales to
ORBCOMM Global, as compared to US$38 million in 1993.

Revenues  from Orbital's space launch vehicle products  decreased
from  US$55,987,000  in  1993  to  US$52,200,000  in  1994.   The
unexpected  decrease was primarily attributable to a  significant
delay  in  production of Orbital's Pegasus space  launch  vehicle
products  as a result of the June 1994 Pegasus XL launch failure.
Revenues from space launch vehicle products increased in 1993, as
compared  to  1992,  due to work performed on  Pegasus  contracts
awarded  in  1992 by BMDO and Brazil's national space agency  and
initial  work  performed on the commercial  contract  awarded  by
ORBCOMM Global.

Revenues  from  suborbital launch vehicle products  decreased  to
US$22,632,000  in  1994  as compared to  US$48,990,000  in  1993.
Revenues  from suborbital launch vehicle products also  decreased
in  1993  from 1992's record revenues of US$82,061,000.  Revenues
from suborbital launch vehicles, which are primarily purchased by
various agencies within the DoD for U.S. military purposes,  have
decreased significantly as defence spending throughout  the  U.S.
Government has been reduced.

Orbital's sole contract with NASA for its orbit transfer  vehicle
products was completed in 1993 after two successful launches.

Space and Electronics Systems revenues increased to US$88,305,000
in 1994 as compared to US$31,287,000 in 1993, due primarily to  a
full   year  of  sales  of  sensors  and  instruments  equal   to
US$28,482,000 following the September 1993 acquisition of ASO and
19  weeks  of  sales of spacecraft systems and  defence  avionics
equal  to US$44,998,000 following the August 1994 acquisition  of
Fairchild.  Space systems revenues increased to US$31,287,000  in
1993  from US$20,715,000 in 1992, primarily as a result of  sales
of  sensors and instruments and sales of MicroStar satellites  to
ORBCOMM Global.  Space systems revenues in 1992 consisted  solely
of sales of satellite systems to NASA and the U.S. Air Force.

Communications  and  Information Systems  revenues  decreased  to
US$58,808,000 in 1994 from US$71,391,000 in 1993.   The  decrease
was  attributable  primarily to a decrease in  sales  to  ORBCOMM
Global  of  US$10,455,000  as the initial  contract  for  network
software  neared completion, and a decrease in sales of satellite
tracking  systems  of  US$8,443,000  as  a  large  contract   was
completed  in  1994.  Sales of Magellan's satellite  navigational
instruments   were   US$37,144,000  in  1994   as   compared   to
US$32,900,000  in 1993 and US$29,557,000 in 1992.   The  increase
from  1993  was  due to a significant increase in the  number  of
products  sold  offset,  in  part, by lower  average  unit  sales
prices.    Communications   and  Information   Systems   revenues
increased  in 1993 as compared to 1992 as a result  of  sales  of
network software and satellite tracking systems to ORBCOMM Global
under  a  contract  awarded in 1993  and  as  a  result  of  work
performed  on a large satellite tracking system contract  awarded
in late 1992.

Gross Profit.  Orbital's gross profit for 1994, 1993 and 1992 was
US$64,881,000,  US$52,883,000  and  US$45,529,000,  respectively.
Gross  profit  margin as a percentage of sales for those  periods
was  approximately 29.1%, 23.7%, and 22.3%, respectively.   Gross
profit margin during 1994 reflected higher profit margins on  ASO
and  Fairchild  products offset in part by  cost  growth  on  the
Taurus  space  launch  vehicle  development  program,  the  first
product  of  which  was  successfully  launched  in  March  1994.
Additionally, gross profit margin was decreased by cost growth on
the  Pegasus  program  as a result of the June  1994  Pegasus  XL
launch failure.

Research  and  Development  Expenses.  Research  and  development
expenses   during   1994,  1993  and  1992  were   US$14,389,000,
US$14,885,000  and  US$10,586,000,  respectively.   Research  and
development  spending  during 1994 and 1993  reflected  Orbital's
continued  development of its Pegasus XL and Taurus space  launch
vehicles  and  development  of  lower-cost  satellite  navigation
equipment.   In 1994, Orbital incurred approximately US$2,500,000
of  unexpected research and development costs related to the June
1994 failure of its Pegasus XL vehicle.

Selling,  General and Administrative Expenses.  Selling,  general
and   administrative  expenses  for  1994,  1993  and  1992  were
US$39,751,000 (or 17.9% of revenues), US$25,897,000 (or 11.6%  of
revenues) and US$28,615,000 (or 14.0% of revenues), respectively.
The  significant increase in selling, general and  administrative
expenses  and  its  related percentage of revenues  in  1994  was
attributable  to  a full year of ASO's expenses (US$4,666,000  in
1994,  or 16.8% of ASO's revenues), nineteen weeks of Fairchild's
expenses (US$6,409,000 in 1994, or 14.0% of Fairchild's revenues)
and  significant  selling,  general and  administrative  expenses
related  to  initial marketing activities for  Orbital's  ORBCOMM
project  (US$5,470,000  in 1994) offset in  part  by  significant
company-wide cost reduction initiatives adopted during  1994  and
1993.

Interest  Income and Interest Expense.  Net interest  income  was
US$37,000,  US$356,000 and US$738,000 for 1994,  1993  and  1992,
respectively.   Interest  income reflects  interest  earnings  on
short-term  investments  reduced  by  interest  expense  (net  of
capitalized interest of US$5,500,000, US$3,500,000 and US$850,000
in  1994, 1993 and 1992, respectively) for outstanding amounts on
Orbital's revolving credit facility, the public debentures and on
debt incurred in 1994 related to the Fairchild acquisition.

Equity in Earnings (Losses) of Affiliates.  Equity in earnings of
affiliates  in 1994 and 1993 primarily represents elimination  of
US$1,264,000 and US$2,436,000, respectively, of profits on  sales
to  ORBCOMM Global, due to ORBCOMM Global's capitalization of its
purchases  from  Orbital.  There were no sales to ORBCOMM  Global
prior to 1993.

Provision  for  Income  Taxes.   Orbital  adopted  SFAS  No.  109
effective January 1, 1993.  The cumulative effect on prior  years
of  this  change in accounting principle increased net income  in
1993  by  approximately US$200,000.  The effect of adopting  SFAS
109  on  income  from  continuing  operations  in  1993  was  not
material.

Orbital   recorded   income  tax  provisions   of   US$2,081,000,
US$2,288,000   and  US$1,630,000  for  1994,   1993   and   1992,
respectively.  Orbital's effective tax rate for these periods  of
approximately  28%  is primarily a result of  non-tax  deductible
goodwill amortization related to its acquisition of Space Data in
1988  and  Fairchild  in  1994,  offset  by  tax-exempt  interest
earnings and U.S. Federal research and experimental tax credits.

Liquidity and Capital Resources

Orbital's growth has required substantial capital to fund both an
expanding  business base and significant research and development
and  capital investment expenditures.  Additionally, Orbital  has
historically  made  strategic  acquisitions  of  businesses   and
routinely  evaluates  potential acquisition candidates.   Orbital
expects  to  continue  to pursue potential acquisitions  that  it
believes would augment its marketing, technical, manufacturing or
financial capabilities.  Orbital has funded these requirements to
date, and expects to fund its requirements in the future, through
cash  generated  by operations, working capital loan  facilities,
asset-based  financings, joint venture arrangements, and  private
and public equity and debt offerings.

During  the quarter ended June 30, 1995, Orbital entered  into  a
US$20  million  fixed-rate unsecured debt  financing  arrangement
with  a private insurance company.  The debt has a six-year  term
and  bears  interest  at 10 1/2% per annum.   The  debt  arrangement
restricts the payment of dividends and contains certain covenants
with  respect  to Orbital's working capital, fixed charge  ratio,
leverage  ratio  and tangible net worth.  Additionally,  in  June
1995,  Orbital  completed  a private  placement  of  two  million
Orbital  Common  Shares, receiving net proceeds of  approximately
US$32   million.   Orbital's  shares  were  placed  with  various
offshore institutional investors and the issuance was exempt from
public  registration  pursuant  to  Regulation  S  of  the   1933
Securities  Act,  as  amended.  In August  1994,  Orbital  issued
secured  notes  totalling approximately  US$24,200,000  to  eight
financial  institutions,  to  support  Orbital's  acquisition  of
Fairchild.    The  notes  have  an  average  interest   rate   of
approximately 8_% and generally mature on a monthly basis over  a
three- to five-year period.

Cash,   cash   equivalents   and  short-term   investments   were
US$39,817,000  at June 30, 1995, and Orbital had  short-term  and
long-term   debt   obligations   outstanding   of   approximately
US$106,955,000.   The  outstanding  debt  relates  primarily   to
advances  under Orbital's line of credit facility, secured  notes
issued  in  connection with the Fairchild acquisition,  unsecured
notes issued in 1995, fixed asset financings and Orbital's public
debentures.   During  the quarter ended June  30,  1995,  Orbital
converted,  at  a  premium,  approximately  US$3,000,000  of  its
convertible  debentures  at  the  request  of  certain  debenture
holders, issuing approximately 209,000 Orbital Common Shares.

Orbital's revolving credit facility provides for total borrowings
from   an  international  syndicate  of  six  banks  of   up   to
US$65,000,000, subject to a defined borrowing base  comprised  of
certain  contract  receivables.   Approximately  US$6,113,000  of
borrowings were outstanding under the facility at June 30,  1995,
against    an   available   facility   limit   of   approximately
US$25,491,000.   At June 30, 1995, the average interest  rate  on
outstanding  borrowings  under this  facility  was  approximately
8.2%.  Borrowings are secured by contract receivables and certain
other  assets.  The facility restricts the payment  of  dividends
and  contains certain covenants with respect to Orbital's working
capital,  fixed  charge ratio, leverage ratio  and  tangible  net
worth, and expires in September 1997.

Orbital's  operations used net cash of approximately US$8,466,000
in  the  six  months ended June 30, 1995.  Orbital also  invested
approximately  US$9,689,000 in the ORBCOMM  System  and  incurred
US$9,854,000   of  capital  expenditures  related  primarily   to
spacecraft production and test equipment.

Orbital  expects  that its 1995 capital needs  for  its  existing
operations, including its planned US$5,000,000 net investment  in
the  ORBCOMM System, will in part be provided by working capital,
cash   flows  from  operations,  credit  facilities,  asset-based
financings, customer financings and operating lease arrangements.
Additionally, Orbital intends to invest at least US$67,500,000 in
the X-34 program, which investment will be required over the next
four   years,  including  approximately  US$5,000,000  in   1995.
Orbital  believes  that it may require additional  equity  and/or
debt financing to fund fully its currently planned operations and
capital  requirements, to meet its potential increased investment
in the ORBCOMM System and to meet its investment requirements for
the X-34 program.

Management and Employees

Executive Officers and Directors

The  following  table  sets forth the name,  city  of  residence,
position  and  principal  occupation of  each  of  the  executive
officers and directors of Orbital as of September 1, 1995.  As of
September  29,  1995,  the executive officers  and  directors  of
Orbital beneficially owned, as a group, approximately 3.7% of the
outstanding Orbital Common Shares.


                                             Principal
 Name and        Director  Position with      Occupation if
 Residence       Since     Orbital            Different than
                                             Office Held
                                   
 David W.        1982      Chairman of the    
 Thompson                  Board, President
 Reston,                   and Chief
 Virginia                  Executive Officer

 Bruce W.        1982      Executive Vice
 Ferguson                  President and
 Great Falls,              General Manager/
 Virginia                  Communications
                           and Information
                           Systems Group and
                           Director

 James R.        1992      Executive Vice
 Thompson                  President and
 Huntsville,               General
 Alabama                   Manager/Launch
                           Systems Group and
                           Director

 Jack A.         1994      Executive Vice
 Frohbieter                President and
 Germantown,               General
 Maryland                  Manager/Space and
                           Electronics
                           Systems Group and
                           Director
 
 Fred C. Alcorn  1983      Director           President, Alcorn
 Houston, Texas                               Oil & Gas and
                                              Alcorn
                                              Development
                                              (Real Estate)
 
 Kelly H. Burke  1984      Director           Chairman,
 Alexandria,                                  Stafford, Burke &
 Virginia                                     Hoaxer
                                              (Aerospace
                                              consulting)
 
 Daniel J. Fink  1983      Director           President, D.J.
 Potomac,                                     Fink Associates,
 Maryland                                     Inc.
                                              (Management
                                              consulting)
 
 Lennard A.      1993      Director           Professor and
 Fisk                                         Chairman,
 Ann Arbor,                                   Department of
 Michigan                                     Atmospheric,
                                              Oceanic, and
                                              Space Sciences,
                                              University of
                                              Michigan
  
 Jack L.         1993      Director           Professor of
 Kerrebrock                                   Aeronautics and
 Lincoln,                                     Astronautics,
 Massachusetts                                Massachusetts
                                              Institute of
                                              Technology
 
 J. Paul         1984      Director           Managing
 Kinloch                                      Director, Lehman
 Los Angeles,                                 Brothers
 California                                   (Investment
                                              Banking)
 
 Douglas S.      1983      Director           President and
 Luke                                         CEO, WLD
 Coral Gables,                                Enterprises, Inc.
 Florida                                      (Investments)
 
 John L.         1993      Director           Consultant
 McLucas
 Alexandria,
 Virginia
 
 Harrison H.     1983      Director           Consultant
 Schmitt
 Albuquerque,
 New Mexico
 
 Scott L.        1982      Director           Consultant
 Webster
 Chandler,
 Arizona
 
 Antonio L.                Executive Vice
 Elias                     President and
 McLean,                   General
 Virginia                  Manager/Advanced
                           Projects Group
 
 Carlton B.                Senior Vice
 Crenshaw                  President/Finance
 Herndon,                  and
 Virginia                  Administration
 
 Leslie C.                 Senior Vice
 Seeman                    President,
 Bethesda,                 General Counsel
 Maryland                  and Secretary
 
 

For  information  regarding executive and director  compensation,
and  a description of Orbital's stock option plans, reference  is
made   to  the  excerpt  from  Orbital's  Proxy  Statement  dated
March 27, 1995, attached as Annex "III" to this Proxy Circular.

Indebtedness of Directors and Officers

There  is no indebtedness owed by Orbital's directors or officers
to Orbital.

Employees

As  of  June  31,  1995  Orbital had  1,781  full-time  permanent
employees,  none  of  whom are covered by a collective-bargaining
agreement.

Description of Capital

Capitalization

The  following table sets forth the capitalization of Orbital  as
of June 30, 1995.
                                                 June 30,
                                                   1995
                                                  (US$ in
                                                thousands)
Long-term debt:                                              
    Long-term obligations, net of current          $ 19,203
    portion                                                
    10 1/2% Senior Notes due 2002                    20,000
    6 3/4% Convertible Subordinated Debentures     $ 56,000 
    due 2003
Total long-term debt                               $ 95,203
Shareholders' equity:                                        
    Preferred Shares, par value $0.01 per                    
    share: 10,000,000                                    --  
     authorized; no shares issued and                        
    outstanding                                              

    Common Shares, par value $0.01 per                  227
    share: 40,000,000                                 
     authorized; 22,636,357 shares issued             
    and outstanding                                 
     after adjusting for 15,735 shares in          
    treasury (1)

    Additional paid-in capital                      237,549
    Unrealized losses on short-term                    (221)
    investments
    Retained earnings (deficit)                      (1,941)
Total shareholders' equity                        $ 235,614
Total capitalization                              $ 330,817

Note:
(1)  Excludes  3,900,945  Orbital  Common  Shares  issuable  upon
     conversion  of  Orbital's  6 3/4%  Convertible  Subordinated
     Debentures  due  2003  and 1,661,146 Orbital  Common  Shares
     reserved for issuance pursuant to options outstanding as  of
     September 8, 1995 with exercise prices ranging from  US$7.50
     to US$22.00 per share.

Common Shares

Orbital has authorized 40,000,000 Common Shares, par value  $0.01
per  share  of  which approximately 22,636,357 are issued  as  at
June 30, 1995.  Holders of Orbital Common Shares are entitled  to
one  vote per share on all matters to be voted on by shareholders
including  the election of directors.  Subject to the  rights  of
holders  of  any  Orbital Preferred Shares that  may  be  issued,
holders  of  Orbital Common Shares are entitled to  receive  such
dividends  as may be declared from time to time by the  board  of
directors of Orbital from funds legally available therefor.  Upon
liquidation, dissolution or winding-up of Orbital, the holders of
Orbital  Common  Shares will be entitled  to  share  ratably  all
assets  available for distribution to shareholders after  payment
of  liabilities, subject to prior distribution rights of  holders
of  Preferred Shares then outstanding.  The Orbital Common Shares
have  no  preemptive  or conversion rights or other  subscription
rights.   There  are  no  redemption or sinking  fund  provisions
applicable to the Common Shares.

Preferred Shares

Orbital  has  authorized 10,000,000 Preferred Shares,  $0.01  par
value  per  share of which none are issued.  See "Special  Voting
Share"  below.   Orbital's  board  of  directors  is  authorized,
without any further action by the shareholders, to determine  the
rights,  preferences, privileges and restrictions of the unissued
Preferred Shares.

Special  Voting  Share.   In  connection  with  the  Arrangement,
Orbital's  Board  of  Directors  will  designate  the  Series   A
Preferred  Stock  as  a  series of  Preferred  Shares,  and  will
authorize  the  issue  of one Series A Preferred  Share,  as  the
Special  Voting  Share,  to  the Trustee  under  the  Voting  and
Exchange Trust Agreement.  Except as otherwise required by law or
Orbital's  Restated  Certificate of Incorporation  (the  "Orbital
Restated  Certificate"),  the holder of  record  of  the  Special
Voting  Share will have a number of votes equal to the number  of
Orbital  Common Shares issuable upon exchange of all  outstanding
Exchangeable  Shares  (not owned by Orbital or  its  Affiliates).
The holders of Orbital Common Shares and the Special Voting Share
will  vote  together as a single class on all matters, except  as
may  be  required  by  applicable  law.   In  the  event  of  any
liquidation, dissolution or winding up of Orbital, the holder  of
the  Special  Voting Share shall not be entitled to  receive  any
assets of Orbital available for distribution to its shareholders.
The  holder of the Special Voting Share shall not be entitled  to
receive dividends.  At such time as the Special Voting Share  has
no  votes attached to it because there are no Exchangeable Shares
outstanding  not owned by Orbital or its Affiliates, the  Special
Voting Share will be cancelled.

Dividend Policy

Orbital  has  never  paid a cash dividend on the  Orbital  Common
Shares.   Orbital currently intends to retain earnings  primarily
for  working  capital and product development and therefore  does
not  anticipate paying dividends in the foreseeable  future.   In
addition,  Orbital is subject to certain contractual restrictions
on its ability to pay dividends.

Transfer Agent

Orbital's  transfer  agent with respect  to  the  Orbital  Common
Shares  is  The  First  National Bank of  Boston.   Acquisition's
transfer  agent  with  respect  to  the  Exchangeable  Shares  is
expected to be Montreal Trust Company of Canada.

Independent Auditors

Orbital's independent auditors are KPMG Peat Marwick LLP.


                   INFORMATION CONCERNING MDA

Business

MDA was incorporated under the laws of Canada on February 3, 1969
by  letters  patent under the Canada Corporations Act.   MDA  was
subsequently continued under the CBCA on May 3, 1976.   The  head
and principal office of MDA is located at 13800 Commerce Parkway,
Richmond, British Columbia, V6V 2J3.

Subsidiary Companies

MDA owns 100% of the following active subsidiary companies:
                   INFORMATION CONCERNING MDA

Business

MDA was incorporated under the laws of Canada on February 3, 1969
by  letters  patent under the Canada Corporations Act.   MDA  was
subsequently continued under the CBCA on May 3, 1976.   The  head
and principal office of MDA is located at 13800 Commerce Parkway,
Richmond, British Columbia, V6V 2J3.

Subsidiary Companies

MDA owns 100% of the following active subsidiary companies:

Company                         Jurisdiction of
                                Incorporation

MacDonald Dettwiler             British Columbia
Technologies Ltd.

MacDonald Dettwiler             U.S.A.
Technologies Inc.

MacDonald Dettwiler Pty. Ltd.   Australia

MacDonald Dettwiler Limited     United Kingdom

PSC International (Europe)      United Kingdom
Limited

At  June  30, 1995 MDA owned 89.6% of Earth Observation  Sciences
Limited, a corporation incorporated under the laws of the  United
Kingdom,  and  will  acquire  the balance  of  its  shares  as  a
condition to the Arrangement.

General

MDA  is  a  leading supplier of commercial space  remote  sensing
ground  stations,  installed in over  20  countries,  capable  of
handling   all  major  optical  and  radar  imaging,   or   Earth
observation,  satellites.   MDA  is  also  a  major  provider  of
advanced   space-qualified  software,  air  navigation   systems,
defence  electronic  systems and network communications  training
and consulting.

MDA's customers for systems are usually Fortune-500 companies and
government agencies worldwide.  MDA's basic business strategy  is
to  develop customized systems for individual clients, drawing on
proprietary  technologies and on off-the-shelf  products.   MDA's
strength is in undertaking fixed price projects and delivering on
time  and  within  the customer's budget.  MDA  currently  has  a
strategy of reducing its reliance on contracts from or related to
the  Canadian Federal Government through operations and alliances
outside  of Canada.  MDA is seeking to expand its export  markets
through understanding and accessing foreign funding sources  such
as multi-lateral development agencies.

Utilizing  existing  technologies and  seeking  opportunities  in
areas  that  complement MDA's business in terms of  technological
capabilities  and  markets,  MDA is currently  developing  a  new
business  strategy to capitalize on higher margin  opportunities.
As  part  of  the strategy, MDA's PSC division is  extending  its
consulting  services by negotiating worldwide service  agreements
with  manufacturers of computer network equipment.  The  strategy
also  contemplates MDA charging a per-use fee for data  processed
by  systems  provided by MDA.  In addition, MDA  may  acquire  an
equity  interest in ventures where it traditionally sold systems.
MDA's  participation  in  EarthWatch  Inc.  is  a  part  of  this
strategy.   This  strategy is also consistent  with  MDA's  25.4%
interest  in RSI, which has worldwide rights to market data  from
the soon to be launched RADARSAT satellite.  In other situations,
MDA  will  package components of customized systems into products
which  can be sold to many buyers with few changes.  This  latter
strategy  is designed to permit MDA to bring products  to  market
economically  by  capitalizing on the initial  development  of  a
system.   An  example of a new product opportunity is the  radar-
jamming system of the Space and Defence Systems business area.

MDA's business is divided into four business areas consisting  of
Geo-Information  Systems,  Aviation Systems,  Space  and  Defence
Systems and Communications, which are described in detail in  the
following sections.

Geo-Information Systems

Geo-Information Systems, MDA's largest business area in terms  of
revenues,  involves the development of systems for the management
of  Earth resources and the environment.  This business  area  is
built on MDA's expertise in Earth observation ground stations and
related markets.  The Geo-Information Systems business area  also
provides   operational  and  post-delivery  support   to   ensure
operational  efficiency of systems delivered  to  its  customers.
This  support includes consulting services, training, maintenance
and test equipment, spare parts and manuals.

MDA  is  one  of  the  world's  leading  companies  in  providing
solutions   for   the  acquisition,  processing,  archiving   and
dissemination of non-classified Earth observation data.   Of  the
26 non-secret ground stations in the world, MDA has built or been
involved  in  the  construction  of  23  ground  stations  in  20
countries.   These  ground stations are designed  to  receive  or
process data from some or all of the seven major non-secret Earth
observation  satellites  currently  in  operation.   Among  other
things,  the data is processed to construct useful images  or  is
modified  to  enhance  special  characteristics  or  to   correct
distortions and anomalies.

A  significant  portion of MDA's business in this  area  involves
upgrades  to existing systems.  Such upgrades are required  as  a
result  of  the  launch  of  new technologically-advanced  Earth-
observation  satellites in order to ensure that  existing  ground
stations  are  able to process the data that the  new  satellites
provide.   Delays  in  the  launch of  such  new  satellites  can
adversely impact the ground station upgrade business.

The  upgrade business has recently declined, in part due  to  the
failure  of  the U.S. LANDSAT-6 satellite, which was launched  in
1994  but  failed to achieve orbit.  The only satellite  launched
since  then  was  the  European Space Agency's  ERS-2  which  was
launched  in April 1995.  While MDA performed about $3.5  million
of  ground  station  upgrades in Europe for ERS-2  during  fiscal
1995,  additional upgrading work will be relatively minor because
this satellite uses technology similar to ERS-1, launched in July
1991.   However, several new technologically-advanced  satellites
are  scheduled  for launch by the end of 1996 and these  launches
are  expected  to  increase demand for new  and  upgraded  ground
stations.

Over  the  longer  term, other major trends  affecting  the  Geo-
Information Systems business area include technological advances,
the   loosening  of  government  restrictions,  and   a   growing
commercial  value  and  profit  potential  in  the  ownership  of
satellites  and  ground  stations.   The  technological  advances
include  a  declining  cost to obtain and disseminate  satellite-
based   Earth  information  and  the  proliferation  of  low-cost
personal  computers  capable  of  receiving  these  images.   The
loosening  of  government restrictions mainly involves  the  1994
decision  of  the  U.S.  government  to  begin  issuing  licences
permitting  private companies to obtain and sell  high-resolution
Earth  images  of a quality previously restricted  to  government
intelligence agencies.  MDA expects that these trends  will  lead
to  an  increase in the number of satellites and ground stations,
and  to  the ownership of some satellites and ground stations  by
private-sector companies.

MDA  has  completed several Earth information projects  involving
mission-control and mission-management systems for  the  Canadian
Space  Agency's RADARSAT satellite, scheduled for launch in  late
1995,  which  contracts  totalled $33.6 million.   MDA  has  also
completed  a  multi-year project to build a specialized  software
and  hardware ground system that refines raw data from  RADARSAT.
This  $10  million  system was installed at the Gatineau,  Quebec
ground station that MDA has upgraded several times since the mid-
1980s.   MDA  owns approximately 25% of RSI, which has  worldwide
rights to market data from the new RADARSAT satellite imagery.

In  addition  to space-based Earth observation, MDA builds  other
systems related to Earth information, including the $10.8 million
Fast  Mapping System for the government of Malaysia,  which  will
allow  the  Malaysian government to quickly update  and  generate
digital mapping products from satellite and airborne sensors, and
the  installation of a multimillion-dollar Airborne Radar  System
in China, which is used for flood monitoring and natural disaster
relief.

MDA  has  developed  and  delivered  airborne  Earth  observation
systems  with  both  electro-optical  and  radar  sensors.    The
Integrated  Radar  Imaging  System,  a  side-looking  radar  that
provides  detailed images of the ground in any light  or  weather
conditions,  makes high-resolution imagery available in  realtime
both  on  board an aircraft and at transportable ground stations.
Airborne Earth observation systems have been used for a number of
applications  including  mapping, forest  management,  oil  spill
recovery and ice flow monitoring in the Arctic.  MDA is a  member
of   a   team,   led  by  Raytheon  Corporation   of   Lexington,
Massachusetts,  that was awarded a contract  from  the  Brazilian
Government  in  May  1995  for  the  development  of  an   Amazon
surveillance  system.   MDA is currently  negotiating  the  final
terms of its subcontract with Raytheon.

In  mission management, under a contract with the European  Space
Agency  ("ESA"),  MDA has built a system for managing  the  ERS-1
satellite's instrument package and for cataloguing and  archiving
the  vast quantities of data the satellite will deliver over  its
lifetime.   MDA  expects  to  use this  technology  in  providing
satellite  mission  management systems in the  future,  including
systems  for  ESA's  ENVISAT satellite, which  is  scheduled  for
launch in 1998.

Aviation Systems

Since  1987, MDA's Aviation Systems business area has focused  on
specific aviation niche markets, including automated aeronautical
information systems and automated air traffic management systems.
This  division  was established to take advantage  of  a  growing
trend  toward  commercialization of civil  aviation  authorities.
This  commercialization typically leads to a strong incentive  to
cut  costs  by  investing in automation.  At the same  time,  the
airline industry estimates several billion dollars will be  spent
worldwide  before  the  year  2000 on  upgrading,  replacing  and
automating  civil aviation traffic management systems.   To  meet
these  developments MDA's Aviation Systems business area provides
the following:

Aeronautical Information Systems.  MDA builds and markets Pegasus-
AIS (unrelated to Orbital's Pegasus launch vehicle), an automated
aeronautical information management system.  The first sale of  a
Pegasus-AIS system was to the Belgian Air Force for $1.8 million.
Faster  and  less  expensive to operate than  traditional  manual
systems,  Pegasus-AIS  provides  pilots  and  other  users   with
aeronautical  and  meteorological  information.   MDA  has   been
developing  the underlying technology for Pegasus-AIS since  1989
by  way  of  customized automated briefing systems  that  MDA  is
building for civil aviation authorities in Australia, Norway  and
Belgium.   In  addition,  MDA  incorporates  its  knowledge  into
broader   air  traffic  management  systems.   MDA  has  recently
completed  work  on  a  $2.7 million AIS  project  in  India  for
Raytheon.

Air  Traffic Management Systems.  Air traffic management  systems
allow  air traffic controllers to guide pilots in flight.   These
systems  combine  information  about  flights,  routes,  weather,
navigational  aids, airways and airports and deliver  it  to  air
traffic controllers in a form that enables timely, safe decisions
to  be  made.   In  Canada,  MDA is  currently  working  under  a
subcontract  to Hughes Aircraft of Canada Limited  ("Hughes")  to
develop  and deliver air traffic management software as  part  of
the Canadian Automated Air Traffic System.  The subcontract value
was increased by $24 million during fiscal 1995 to a total of $85
million.   Hughes' prime contract with Transport Canada is  being
renegotiated.   In Switzerland, MDA has a $4 million  subcontract
for  a  Hughes air traffic control project.  Under a  $3  million
subcontract to Hughes, MDA is providing a military version of the
Canadian  Automated Air Traffic System to Canada's Department  of
National  Defence.   Together, MDA  and  Hughes  are  pursuing  a
growing   number   of  air  traffic  management   systems   sales
opportunities  around the world, including a  bid  on  two  large
projects  in Britain and the execution of projects in  China  and
Indonesia.

Space and Defence Systems

Many  of  MDA's  technologies  are  directly  applicable  to  the
development of space and defence systems.  Defence markets around
the world have declined as governments reformulate defence policy
in  the wake of the Gulf War and the collapse of the Soviet Bloc.
MDA  has,  however, sought to identify niches that are likely  to
grow  as  defence  agencies  focus  on  peace-time  surveillance,
monitoring  and  defensive capabilities.  MDA's  defence  systems
include   naval  mine  countermeasures,  artillery  command   and
control, radar deception system and military materiel management.
In  space-related work, MDA continues to provide  major  software
development efforts as part of Canada's contribution to the Space
Station  project.  This activity provides an opportunity for  the
enhancement of MDA's space-qualified software capabilities.   MDA
has  actively  pursued space and defence systems  business  since
1988.

Naval Mine Countermeasures System.  Since 1988 MDA has worked  on
a  series  of projects to develop geocoded sonar image  modelling
and  mosaicking  techniques for mapping  the  ocean  floor.   MDA
currently has an $80 million subcontract from a unit of the  SNC-
Lavalin  Group Inc. of Montreal to develop a mine countermeasures
system  for  the Canadian Navy's Maritime Coastal Defence  Vessel
program.   MDA's  role is to provide command and control  systems
and  operational  ship-borne and shore-based  sonar  sensing  and
processing capabilities for the detection of underwater mines.

Artillery  Command  and Control System.  MDA  is  developing  the
Artillery Regimental Data System to automate certain command  and
control  functions for the Canadian Army.  This project draws  on
MDA's  expertise in the computerization of geographic information
and  in the management of complex database systems.  The Army has
agreed  to  extend the project into the implementation phase  and
has increased the value of MDA's contract to $15.3 million.

Radar  Deception System.  MDA is developing a system  to  protect
airplanes, ships or ground installations from being detected  and
tracked by hostile radars, under contract with the Department  of
National  Defence.   MDA  is  also  pursuing  possible  licensing
arrangements that would allow original-equipment manufacturers to
market and install the product.

Military   Materiel  Management  System.   In  March  1994,   the
Department of National Defence selected the SHL Systemhouse  Inc.
team, which includes MDA as a major subcontractor, to upgrade the
Canadian Forces Supply System.  This inventory management  system
is scheduled for completion in 1997.

Communications

MDA  entered into the computer network communications, consulting
and  training  business in fiscal 1995 with  the  acquisition  of
Ottawa-based PSC Communications Group ("PSC").

PSC  helps  customers  design  and  implement  networks  so  that
computers  can  communicate faster and at  less  cost.   It  also
develops  software for special client needs, such as  to  monitor
networks  and find and correct trouble spots.  PSC  has  built  a
training   relationship  with  U.S.-based  Cisco   Systems   Inc.
("Cisco")  and a worldwide service relationship with Nortel  Inc.
PSC  recently  entered into a training relationship with  Digital
Equipment  Corporation ("DEC").  Training relationships  such  as
those with Cisco and DEC are expected to play a significant  role
in PSC's future business.

PSC's  relationship  with  Cisco,  one  of  the  world's  largest
manufacturers of network equipment, includes acting as a  leading
training  and consulting partner around the world.  PSC  provides
similar services for DEC in the United States.  PSC's arrangement
with  Nortel Inc. involves a new product called Entrust which  is
designed  to ensure the security of computer networking  systems.
PSC  provides post-sales service to Entrust customers,  including
product installation, training and ongoing customer support.  PSC
anticipates offering additional training through its  new  office
in  Australia, which will begin serving Hong Kong and other Asian
markets.

In  addition to classes for specific vendor products, PSC  offers
general  courses  in  computer communications,  aimed  mainly  at
technicians in companies across North America, Europe  and  other
parts  of the world.  PSC also provides software programming  and
consulting  services  for  clients with  network  related  needs,
including   assistance  to  customers  in   developing   advanced
switching  and  network management products and recommending  and
designing an optimal network system.

Contract Pricing and Completion

As  of March 31, 1995 approximately 56% of MDA's active contracts
were   fixed-price   contracts.   MDA  has   developed   costing,
contingency  management, operations and engineering methodologies
to  allow  it  to  undertake  work on a  fixed-price  basis,  and
believes its ability to undertake large-scale systems engineering
and  software development projects on a fixed-price  basis  is  a
major competitive advantage.  The balance of MDA's contracts  are
performed on a cost-plus or limitation of expenditures basis.

The   technical   nature  and  sophistication  of   the   systems
deliverable  under  MDA's contracts require  amendments  to  such
contracts  to  be negotiated, from time to time, in the  ordinary
course  of completing any contracts.  These amendments may relate
to  specifications, delivery times or similar  matters.   In  the
absence of an agreement to such amendments, customers of MDA  may
be  in  a  position to terminate a contract with MDA  and  demand
repayments  and penalties.  Any such termination and  demand  may
have  an  effect  on  the  earnings of MDA.   To  date,  MDA  has
generally been successful in renegotiating contracts as  required
from time to time.

MDA  endeavours  to  negotiate payment terms  in  its  commercial
contracts   that  include  advance  and  progress  payments   for
completion of project milestones.  To secure these payments, some
customers require bank guarantees or letters of credit for all or
part of the advance and progress payments remitted to MDA.

Marketing and Sales

Within  each of its business areas MDA focuses on specific  niche
markets   and  follows  a  strategy  of  seeking  to   thoroughly
understand, anticipate and follow the trends within each niche.

The  Earth  observation market is shifting from one of scientific
orientation  to one of end-user applications.  This has  resulted
in  MDA now providing complete remote sensing centres and mission
management  and  control  systems, where it  previously  marketed
satellite  ground stations.  In image analysis,  the  market  has
matured  for  specific application systems  focused  on  resource
management,  digital mapping and land information.  These  shifts
have  greatly  expanded the size of the markets in which  MDA  is
operating.

The  worldwide defence market is undergoing a rapid  change  from
one centred on conventional forces to one focused on intelligence
gathering  and surveillance by methods that include  the  use  of
sonar  or  radar  mapping  techniques.   Economic  pressures   on
governments  have  caused  defence  agencies  to  focus  on   the
efficient  use of resources through logistics and supply  service
systems.  MDA is focusing its defence marketing efforts on  these
new areas of emphasis.

The  space  market is shifting from a scientific  orientation  to
include    global   environmental   monitoring   and   commercial
applications.  Several large programs such as the U.S. Mission to
Planet  Earth, the Japanese ADEOS program and the European  Space
Agency's Polar Orbiting Earth Mission program will require  large
amounts  of  processing  of remotely sensed  satellite  data  and
mission  management  systems, and MDA has  positioned  itself  to
compete  in  these  emerging  markets.   In  addition,   MDA   is
positioning  itself to participate in the evolving private-sector
ownership  of  satellites and ground stations  through  a  supply
contract and the acquisition of a minority interest in EarthWatch
Inc.,  which  plans  to  launch a privately-owned  Earth  imaging
satellite in 1996.

MDA  has  taken advantage of the trend in the airspace management
market from a focus on radar systems and hardware to advanced air
traffic management systems.  Through participation in programs in
Canada, Australia, Norway, Belgium and Switzerland, MDA is  in  a
position  to  market automated technology that it has  previously
developed   and  provide  applications  expertise   relating   to
aeronautical information systems and flight data processing.

For  the  fiscal year ended March 31, 1995 approximately  44%  of
MDA's  revenues were generated from outside Canada,  an  increase
from  36%  a year earlier.  MDA traditionally works closely  with
domestic  and  foreign  customers to develop  technology.   MDA's
target  is  to  derive 70% of its revenues from  export  markets,
replacing  MDA's  reliance on Canadian government  funding.   The
Canadian  business is higher than the target, in part because  of
MDA's  entry  into several new market niches.  MDA is  developing
export markets for such business.

The  following table presents the source of MDA's gross  revenues
by region during the last three fiscal years:


                     Gross
                   Revenues
                                            
Country               1993       1994     1995
                                
Canada                52%           64%      56%
Asia                  25%           19%      11%
Europe                11%            9%      18%
Australia              4%            4%       3%
South America          1%             -        -
United States          1%            2%       6%
Other                  6%            2%       6%
Total                100%          100%     100%


MDA's  sales  cycle  varies  from as short  as  three  weeks  for
communications  consulting projects to as long as  two  or  three
years  for  certain defence and ground station  projects.   Where
required  MDA  has  the capability to provide customer  financing
through  various agencies, including Canada's Export  Development
Corporation and the Asian Development Bank.

MDA  has  established sales and engineering offices worldwide  to
serve  key  geographic  locations.  These offices  are  presently
located  in  Canada,  the United States,  England,  Malaysia  and
Australia.   In  several  other countries  MDA  has  developed  a
network  of in-country agents to provide necessary assistance  to
sales  teams  and  to provide long-term customer  support.   PSC,
which  is operated as a division of MDA, has its headquarters  in
Ottawa,  Ontario,  and  has branch offices  in  Ontario,  British
Columbia, the United States, England and Australia.

Competition

MDA   participates  in  various  technological  and  geographical
markets.   No  one  competitor is considered  dominant  in  these
markets and MDA knows of no competitor which competes across  its
entire  span  of  technological expertise and markets.   MDA  may
compete against or team with the same company, depending  on  the
nature of each project opportunity.

In   the   Geo-Information  Systems  business  area,  MDA   faces
competition from Datron Systems Inc. and Hughes-STX Corp. of  the
United  States.   Competition in airborne radar systems  includes
Loral  Corp.  (USA) and Thomson CSF (France).  In  the  field  of
land, resource and environmental management systems, MDA faces  a
variety  of  competitors  including  MBB  Dornier  (Germany)  and
Intergraph Corp. (USA).

Competition  in  the Aviation Systems markets  is  broad.   Major
competitors  include  Siemens  Plessy  (Germany),  Alenia  S.p.A.
(Italy) and Thomson CSF (France).

In  the  Space  and  Defence  Systems market,  MDA's  competitive
strategy  is  to take part in a consortium, when appropriate,  in
order to participate in all of the major Canadian programs within
MDA's  particular areas of expertise.  Competitors and consortium
partners  vary  according to the specific program, but  typically
include  Computing Devices Canada, CAE Inc. and  Paramax  Systems
Canada.

PSC's  consulting business has many small competitors, while  its
training  business  competition is limited  to  a  few  companies
licensed by equipment manufacturers.

Research and Development

The  majority  of  systems developed by  MDA  are  large,  highly
interactive  and on the leading edge of technology.  MDA  devotes
significant resources to research and development because it is a
critical  element in the maintenance of MDA's edge  in  a  highly
competitive   and  rapidly  changing  worldwide  market.    MDA's
strategy  is  to  conduct most research and  development  through
commercial contracts with customers providing the funding,  while
maintaining the rights to use and exploit the technology.   Where
full  customer funding is not sufficient, MDA uses its own  funds
and   solicits   assistance  from  various  Canadian   Government
agencies.   A large percentage of MDA's customer-funded  research
is   contracted   from  government  agencies,  particularly   the
Government of Canada which encourages research activity  and  the
development of new systems for export around the world.

MDA's  net  research and development expenditures for the  fiscal
years  ended 1993, 1994 and 1995 were $4.4 million, $3.4  million
and  $2.4 million, respectively.  These amounts exclude customer-
funded  research  and  development and government  assistance  of
$28.8 million, $30.2 million and $31.7 million in 1993, 1994  and
1995, respectively.

Patents and Licenses

MDA  seeks  to protect its proprietary information and technology
under  applicable intellectual property laws.  For work  that  is
not    patentable,    contractual   provisions,    non-disclosure
agreements,  copyright and secrecy laws are all used  to  protect
MDA's proprietary information and technology.

Where  software is sold to a customer under contract,  rights  to
any   proprietary  software  used,  but  developed  outside   the
contract,  are restricted.  MDA seeks to retain, to the  greatest
extent  possible, rights to use the software developed under  the
contract.

Where   MDA  develops  systems  and  software  under  development
contracts  with  the Government of Canada or by  utilizing  funds
provided in the form of government assistance, the Government  of
Canada retains the ownership rights to the products developed and
in  return  licenses  the  technology to  the  developer.   These
licenses  are sole licenses which, in practice, give the  use  of
the  technology  only to the developer of the technology.   Where
systems  and  software are developed under development  contracts
with  other governments, however, MDA seeks to retain all  rights
to ownership and use of the technology developed.

Personnel

A key factor in MDA's success has been the ability to recruit and
retain  the highly qualified people it needs to be successful  in
the  diverse  and rapidly evolving markets in which it  competes.
As  at  March 31, 1995, MDA employed 916 people, the majority  of
whom  hold  university or college degrees.  MDA has no  unionized
employees and believes its relations with its employees are good.

Properties

MDA's  head office, located at 13800 Commerce Parkway,  Richmond,
British  Columbia, is comprised of approximately  182,000  square
feet and is leased until January 2004.  A second Richmond office,
located  at 13571 Commerce Parkway, is comprised of approximately
30,000  square feet and is leased until February 2003.  MDA  also
leases  space in Ottawa, Ontario and Kuala Lumpur, Malaysia,  and
its  subsidiaries  lease space for their operations  in  each  of
Boulder, Colorado; Farnham, England; and Sydney, Australia.   The
PSC  division is headquartered in Ottawa, Ontario and has offices
in   Toronto,   Ontario;  Richmond,  British  Columbia;   McLean,
Virginia; Bristol, England; and Sydney, Australia.

Management's  Discussion and Analysis of Financial Condition  and
Results of Operations

Results  of  Operations for the Quarter ended June 30,  1995  and
Quarter Ended June 30, 1994

For  the  first  quarter ended June 30, 1995, consolidated  gross
revenues  declined to $23.6 million, from $27.6 million  for  the
1994  quarter.  The decline in revenue is primarily due to delays
in  certain  satellite  launches that  impact  demand  for  Earth
information  systems.  MDA believes that revenues  will  increase
through  the  end of its 1996 fiscal year based  on  the  current
schedule of upcoming optical and radar satellite launches.

Despite the drop in revenues for the quarter ended June 30, 1995,
net  earnings  remained constant for the June 30, 1995  and  1994
quarters  at  $0.09 per MDA Common Share.  The earnings  for  the
June  30,  1994  quarter  were affected  by  several  low  margin
development projects that have since been completed.

Other  income  consists  primarily of  interest  income  on  term
deposits,  bank  balances  and  a  lease  receivable  with   RSI.
Interest  income  increased from $115,000 in  the  first  quarter
ended  June  30, 1994 to $232,000 in the 1995 quarter,  primarily
due  to  an  approximate  $9  million increase  in  average  cash
balances.

The  acquisition of The PSC Communications Group  Inc.  in  April
1994 was partially funded by debt, which is reflected in the  net
increase in long-term debt of $3.9 million for the quarter  ended
June 30, 1994.

Results  of Operations for the Fiscal Years ended March 31,  1995
and 1994

Consolidated  gross revenue increased by 8.4% over  the  previous
year.   Fiscal  year 1995 includes $13.9 million of revenue  from
MDA's   newly  acquired  Communications  business   area.    Geo-
Information  Systems  revenues declined  from  $59.3  million  in
fiscal  1994 to $48.8 million in fiscal 1995.  An important  part
of this unit's business is the construction and upgrade of ground-
based   Earth  observation  centres.   The  revenue  decline   is
attributable mainly to a temporary lull in the launching  of  new
Earth  observation satellites and the 1994 launch failure of  the
Landsat-6 satellite, which delayed several customers' programs.

Cost  of sales, consisting of labour, the purchase of deliverable
equipment  and  the engagement of subcontractors, rose  by  6.3%,
from  approximately $75.3 million in fiscal 1994 to $80.1 million
in  fiscal  1995.   In fiscal 1995, equipment and  subcontracting
costs  declined  as a percentage of revenue.  Labour  costs  were
higher  primarily due to the acquisition of PSC,  whose  cost  of
sales  is  comprised  mainly of labour,  and  a  one-time  labour
expense  to  deliver a UNIX based system for MDA's  Earth-imaging
technology.

Research  and  development  expenditures,  before  allowing   for
government assistance, were $4.7 million in fiscal 1995, up  9.9%
from  $4.3  million  in  fiscal 1994.   MDA  received  government
assistance for research and development of $2.3 million in fiscal
1995,  bringing  the  net  expenditure  to  $2.4  million.   That
compared  with net expenditures of $3.4 million in  fiscal  1994.
In  addition  to  the  internally funded expenditures,  customer-
funded  research and development, pursuant to which MDA  conducts
most of its research and development, was $29.3 million in fiscal
1995,  unchanged from fiscal 1994.  In most cases,  MDA  has  the
right  to exploit the technology that results from this customer-
funded research and development.

General  and  administrative expenditures were  $7.8  million  in
fiscal  1995, up from $6.7 million in fiscal 1994.  This increase
includes  $1.6  million attributable to the acquisition  of  PSC,
which  has a slightly higher general and administrative component
than  MDA's  traditional  business.  General  and  administrative
expenditures  for the traditional business declined  by  7.5%  in
fiscal 1995.

The  effective  rate  of income tax for MDA was  46.9%  in  1995,
compared with 44.0% in 1994.  This increase is primarily  due  to
certain losses on foreign operations which MDA was unable to take
advantage of in fiscal 1995 but which can be carried forward  and
used   in   the  future,  if  these  foreign  operations   become
profitable.  These foreign losses are substantially due to start-
up operations in Australia and Britain.

Cash  from operations was $4.2 million in fiscal 1995, down  from
$16.3   million   a  year  earlier.   This  change   is   largely
attributable  to  prepayment  in  fiscal  1994  for  work  to  be
performed  in fiscal 1995 and the recognition of revenue  on  the
percentage  of completion basis.  MDA does not recognize  advance
prepayments on work as revenue until the work is done.  In fiscal
1995,  MDA worked off advance payments that had been received  in
fiscal 1994.

Capital expenditures, primarily required to support growth in the
number   of  employees  and  replacement  of  existing  computing
infrastructure, totalled $3.9 million in 1995 compared with  $3.6
million  in fiscal 1994.  On April 6, 1994, MDA acquired 100%  of
PSC  for  $6.3  million.   The acquisition  was  funded  by  cash
reserves and a term bank loan.

Gross  order backlog at March 31, 1995 was $112 million, compared
to  $136 million at March 31, 1994.  The backlog has been  higher
in  the recent past due to the simultaneous booking of some large
multi-year  programs.   But  at about  one  year's  revenue,  the
backlog  is  typical for MDA's industry.  In addition,  with  the
acquisition of PSC and with changes in certain market niches, MDA
is less reliant on traditional, long-term delivery contracts than
it once was.

As  at the end of the 1995 fiscal year, MDA's bankers have issued
letters of guarantee to certain customers of MDA in the amount of
$9,459,000  of  which  $2,438,000 is guaranteed  by  the  Federal
Government  of  Canada.  If MDA fails to perform as  agreed  with
these  customers and if the letters of guarantee are called,  the
$7,021,000  due to MDA's bankers would be secured by an  existing
general assignment of book debts and assignment of raw materials,
work  in  progress and finished goods.  Inventories  relating  to
contracts  with  the Government of Canada are excluded  from  the
assignment.  The Federal Government of Canada is secured under  a
general recourse agreement, which ranks second to the charge held
by  MDA's  bankers.  A letter of guarantee has never  been  drawn
against with respect to any project.

Results  of Operations for the Fiscal Years ended March 31,  1994
and 1993

Consolidated   gross   revenues   increased   by   19.1%,    from
approximately $85.2 million in fiscal 1993 to $101.4  million  in
fiscal 1994.  Operating costs increased by 18.9% in fiscal  1994,
slightly  below  the increase in revenues for  the  corresponding
1993 period.  Internally funded research and development, net  of
government assistance, decreased from $4.4 million in fiscal 1993
to  $3.4  million  in  fiscal  1994.   Research  and  development
decreased   as   the   Geo-Information  Systems   business   area
substantially  completed  the development  phase  of  its  ground
station upgrade program in fiscal 1993.

Operating earnings increased to $5.3 million in fiscal 1994  from
$4.3  million  in fiscal 1993, an increase of 22%.  Other  income
decreased  from  $634,000 in fiscal 1993 to  $532,000  in  fiscal
1994.   The  decrease in interest income due  to  lower  interest
rates  is partially offset by interest income earned on  the  10%
lease receivable with RSI.

Net  cash provided by operations reached $16.3 million in  fiscal
1994,  compared  with  $0.5  million in  fiscal  1993.   Deferred
revenue  was a major reason for this change, increasing by  $12.0
million.    Deferred  revenue  represents  amounts  invoiced   to
customers  in  excess  of revenue earned.   Capital  expenditures
amounted to $3.6 million in 1994.

Directors and Officers

The following table sets forth the directors and officers of MDA,
their municipality of residence, their principal occupations, the
year  when  they became directors and the number  of  MDA  Common
Shares  and  MDA Options held by them.  Following  the  Effective
Date, Orbital expects to appoint new directors to the MDA Board.




                                                       Principal           
                                                     Occupation if    No. of MDA
                                        Director    Different than      Common
  Name and Residence        Office       Since        Office Held      Shares or
                                                                      MDA Options
                                                                         Held
                                                                 
 J. Brian Aune            Director      1986        Chairman, St.      Nil
 Westmount, Quebec                                  James Financial
                                                    Corporation
                                                    (Private
                                                    investment
                                                    company)
 
 Winslow W. Bennett*      Director      1982        President,         202,000
 Vancouver, B.C.                                    Winwood Holdings   shares
                                                    Ltd. (Private
                                                    investment
                                                    company)
 
 Michael J. Brown*        Director      1982        President,         100 shares
 West Vancouver, B.C.                               Ventures West
                                                    Management Inc.
                                                    (Venture capital
                                                    management)
 
 Mark H. Leonard          Director      1990        Senior Vice-       Nil
 Toronto, Ontario                                   President,
                                                    Ventures West
                                                    Management Inc.
                                                    (Venture capital
                                                    management)
 
 C. Calvert Knudsen*      Director      1988        Director,          50,000
 Seattle, Washington,                               MacMillan Bloedel  shares
 U.S.A.                                             Limited, formerly
                                                    Chairman and
                                                    Chief Executive
                                                    Officer of
                                                    MacMillan Bloedel
                                                    (Integrated
                                                    forest products
                                                    company)
 
 John S. MacDonald        Director,     1969                           1,110,449
 Vancouver, B.C.          Chairman of                                  shares
                          the Board                                    1,994
                                                                       options (1)
 
 John W. Pitts*           Director,     1982                           1,154,314
 Vancouver, B.C.          Deputy                                       shares
                          Chairman                                     2,341
                                                                       options (1)
 
 Daniel E. Friedmann      Director,     1992                           77,041
 Vancouver, B.C.          President                                    shares
                          and Chief                                    161,467
                          Executive                                    options (1)
                          Officer
 
 Mark Dostie              Director,     1995                           5 shares
 Vancouver, B.C.          Engineer
 David N. Caddey          Vice-                                        11,346
 Delta, B.C.              President,                                   shares
                          Space &                                      81,700
                          Defence                                      options (1)
                          Systems
 
 Bernard S. Clark         Vice-                                        15,165
 Delta, B.C.              President,                                   shares
                          Geo-                                         80,660
                          Information                                  options (1)
                          Systems
 
 Robert B. Wallis         Vice-                                        15,002
 Surrey, B.C.             President,                                   shares
                          Aviation                                     82,584
                          Systems,                                     options (1)
                          Chief
                          Financial
                          Officer and
                          Secretary
 
 Gordon D. Thiessen       Controller                                   3,029
 Richmond, B.C.           and                                          shares
                          Assistant                                    10,816
                          Secretary                                    options (1)
 
 John S. Rybinski         Treasurer                                    9,315
 Vancouver, B.C.                                                       shares
 
 Elizabeth J. Harrison,   Assistant                 Partner, Farris,   Nil
 Q.C.                     Secretary                 Vaughan, Wills &
 Vancouver, B.C.                                    Murphy
                                                    (Barristers and
                                                    Solicitors)
 
 *    Member of Audit Committee

Note:

(1)  The outstanding MDA Options are exercisable at varying times
     at prices ranging from $0.90 to $3.75 per MDA Common Share.

All  of the directors of MDA have been engaged for the last  five
years  in  their  present  principal  occupation  or  in  another
capacity  with  the  firms  identified opposite  their  names  or
related  firms,  with the exception of J. Brian Aune.   Prior  to
November 1990, Mr. Aune was Chairman and Chief Executive  Officer
of  Nesbitt Thomson Inc., an investment dealer.  MDA's Board does
not have an executive committee.

Description of Share Capital

The  authorized  share capital of MDA consists  of  an  unlimited
number  of  MDA Common Shares, 205,000 Class A Preference  Shares
and  27,000  Class B Preference Shares.  As at the  date  hereof,
there  are  no  Class A or Class B Preference Shares outstanding.
The  MDA Common Shares are without par value and rank equally  as
to  dividends  and  participation  in  assets  in  the  event  of
liquidation,  dissolution or winding  up.   The  holders  of  MDA
Common  Shares  are entitled to one vote for each share  held  at
general   meetings   of  MDA.   Following   completion   of   the
Arrangement, Acquisition will be the sole shareholder of MDA.

Dividend Record and Dividend Policy

MDA  paid  a  dividend of $1.00 per MDA Common  Share,  totalling
$10,965,000, on July 30, 1992.  No dividends have been paid since
that date.  It is MDA's general policy to retain its earnings for
use in its business and not to pay cash dividends.

Executive Compensation

Summary Compensation Table

The following table sets forth the summary of compensation of the
Chief Executive Officer and the four named executive officers  of
MDA  and  its subsidiaries for the fiscal years ended  March  31,
1994 and 1995:



                                         Long-Term                       
                                         Compensation                    All
  Annual Compensation                       Awards                      Other
                                                                      Compensa-
                                                                        tion
                                                           Securities      
  Name and Principal                              Other      Under       
       Position          Year   Salary   Bonus    Annual    Options     $ (2)
                                  ($)     ($)    Compen-    Granted
                                                 sation (1)     (3)
                                                     

Daniel E. Friedmann      1995   208,000     ---       ---      35,000     7,342
President & C.E.O. (3)
Vice President & C.O.O   1994   202,000     ---       ---      30,000     7,352

John W. Pitts (3)        1995   216,000     ---       ---         ---     7,373
Deputy Chairman
President & C.E.O.       1994   216,000     ---       ---         ---     7,379

John S. MacDonald        1995   186,760  11,560       ---         ---     7,270
Chairman
                         1994   184,690  10,600                   ---     7,269

Bernard S. Clark         1995   113,600  20,499       ---      20,000     7,050
Vice President                                                                 
Geo-Information Systems  1994   108,933  30,947       ---      20,000     9,521

Robert B. Wallis         1995   110,200  20,000       ---      20,000     6,139
Chief Financial Officer                                                        
Vice-President,                                                                
Aviation Systems                                                               
                                                                               
Vice President           1994   107,369  10,000       ---      20,000     6,139
Chief Financial Officer

David N. Caddey          1995   108,600  17,233       ---      20,000     7,044
Vice President                                                                 
Space & Defence Systems  1994   107,400  29,965       ---      20,000     7,050


Notes:

(1)  Perquisites  and other personal benefits do not  exceed  the
     lesser  of $50,000 and 10% of the total of the annual salary
     and  bonus  of the named executive officer for the financial
     year.
(2)  Includes   amounts   paid  pursuant  to   contributions   to
     designated retirement savings plan.
(3)  John  W.  Pitts  served  as President  and  Chief  Executive
     Officer until March 15, 1995.  Daniel E. Friedmann served as
     Executive  Vice President and Chief Operating Officer  until
     he  was  appointed President and Chief Executive Officer  on
     March 15, 1995.


Long-Term Incentive Plan Compensation

MDA  provides long-term incentive compensation to key  employees,
including  executive  officers, in the form  of  options  granted
under   the   Key  Employee  Share  Option  Plan  ("KESOP")   and
predecessor plans, whereby options to purchase MDA Common  Shares
are granted.

The  following table set forth individual grants of options under
the  KESOP  during the fiscal year ended March 31, 1995,  to  the
named executive officers:

 Options Granted During the Financial Year Ended March 31, 1995



                                                            Market Value     
                                  % of Total                     of          
                                   Options                   Securities      
                      Securities  Granted to  Exercise of    Underlying      
                        Under     Employees    Base Price    Options on      
        Name           Options        in      ($/Security)  the Date of    Expiration
                       Granted    Financial                    Grant         Date
                       (#) (1)       Year                   ($/Security)
                                                          

Daniel E. Friedmann     35,000       14%          3.75          3.75         March
                                                                           31, 2001
Bernard S. Clark        20,000        8%          3.75          3.75         March
                                                                           31, 2001
Robert B. Wallis        20,000        8%          3.75          3.75         March
                                                                           31, 2001
David N. Caddey         20,000        8%          3.75          3.75         March
                                                                           31, 2001

Note:

(1)  The  first  20%  of  the  MDA  Common Shares  under  option  vest
     immediately  and  the  remaining  options  vest  over  the   four
     succeeding anniversary dates of the day of grant.

The  following  table sets forth each exercise of options  during  the
fiscal year ended March 31, 1995 by the named executive officers:

     Aggregate Options Exercised During the Financial Year Ended
         March 31, 1995 and Financial Year-End Option Values



                       Securities  Aggregate                       Value of
                        Acquired     Value    Unexercised       Unexercised in
        Name               on      Realized     Options        the Money Options
                        Exercise      ($)      at FY-End         at FY-End($)
                          (#)                     (#)      _________________________
                                              Exercisable  Unexer-   Exer-    Unexer-
                                                           cisable   cisable  cisable
                                                              
Daniel E. Friedmann       ---         ---       81,760      40,000   302,512  148,000
Bernard S. Clark          ---         ---       35,400      24,000   130,980   88,800
Robert B. Wallis          ---         ---       37,500      24,000   138,750   88,800
David N. Caddey           ---         ---       39,700      24,000   146,870   88,800



Pensions

MDA  does  not  maintain  any pension  plans  for  its  executive
officers.   MDA  makes  contributions on behalf  of  all  of  its
employees,   as  part  of  their  compensation,  for   registered
retirement savings plans ("RRSP") equal to the contributions made
by  each  employee to their RRSP up to a maximum of  5%  of  that
person's base salary.

Auditors

MDA's auditors are KPMG Peat Marwick Thorne, 777 Dunsmuir Street,
Vancouver, British Columbia V7Y 1K3.

Registrar and Transfer Agent

Montreal Trust Company, at its principal offices in Vancouver and
Toronto,  is the registrar and transfer agent for the MDA  Common
Shares.

Stock Exchange Listings

The MDA Common Shares are listed on the TSE and the VSE and trade
under the symbol "MDA".


               COMPARISON OF SHAREHOLDERS' RIGHTS

Former  MDA  Shareholders  will,  at  the  Effective  Date,   own
Exchangeable  Shares  that are exchangeable  for  Orbital  Common
Shares.  Pursuant to the Voting and Exchange Trust Agreement  the
Trustee  may, at the direction of the holders of the Exchangeable
Shares,  exercise  votes equivalent to those  of  Orbital  Common
Shares.   At the Effective Date, Acquisition will be a  reporting
issuer  under  the  laws  of the province  of  British  Columbia,
Ontario and certain other provinces.

While  the  rights and privileges of stockholders of  a  Delaware
corporation such as Orbital are, in many instances, comparable to
those  of shareholders of a corporation under the CBCA,  such  as
MDA   and  Acquisition,  there  are  certain  differences.    The
following  is a summary of the material differences  between  the
rights of holders of MDA Common Shares, the rights of holders  of
Exchangeable Shares, and the rights of holders of Orbital  Common
Shares.  These differences arise from differences between  United
States  and  Canadian securities laws, between the DGCL  and  the
CBCA,  and  between  the  MDA  articles  and  by-laws  (the  "MDA
Articles"  and  the  "MDA By-Laws," respectively),  Acquisition's
articles   (the   "Acquisition  Articles")   and   by-laws   (the
"Acquisition  By-laws") as proposed to be amended  in  connection
with the Arrangement and the Orbital Restated Certificate and by-
laws   (the  "Orbital  By-Laws").   For  a  description  of   the
respective rights of the holders of MDA Common Shares and Orbital
Common Shares, see, respectively, "Information Concerning  MDA  -
Share  Capital Structure" and "Information Concerning  Orbital  -
Description of Capital."

Extraordinary Transactions - Vote Required

Under the CBCA, certain extraordinary corporate actions, such  as
certain  amalgamations, continuances, sales, leases or  exchanges
of  all  the  assets of a corporation other than in the  ordinary
course  of  business, and other extraordinary  corporate  actions
such  as  liquidations, dissolutions and (if ordered by a  court)
arrangements, are required to be approved by special  resolution.
A  special resolution is a resolution passed by a majority of not
less  than  two-thirds of the votes cast by the shareholders  who
voted in respect of that resolution.  In certain cases, a special
resolution to approve an extraordinary corporate action  is  also
required  to be approved separately by the holders of a class  or
series of shares.

The  DGCL  requires  the affirmative vote of a  majority  of  the
outstanding  stock  entitled to vote  thereon  to  authorize  any
merger,  consolidation, dissolution or sale of substantially  all
of  the assets of a corporation, except that, unless required  by
its certificate of incorporation, no authorizing stockholder vote
is  required  of  a corporation surviving a merger  if  (a)  such
corporation's certificate of incorporation is not amended in  any
respect  by  the  merger,  (b)  each  share  of  stock  of   such
corporation  outstanding immediately prior to the effective  date
of  the merger will be an identical outstanding or treasury share
of  the  surviving corporation after the effective  date  of  the
merger,  and (c) the number of shares to be issued in the  merger
plus   those  initially  issued  upon  conversion  of  any  other
securities to be issued in the merger do not exceed 20%  of  such
corporation's outstanding common stock immediately prior  to  the
effective date of the merger.  Stockholder approval is  also  not
required under the DGCL for mergers or consolidations in which  a
parent  corporation merges or consolidates with a  subsidiary  of
which  it  owns  at least 90% of the outstanding shares  of  each
class  of  stock.   The  Orbital Restated  Certificate  does  not
require  a  greater percentage vote for such actions except  with
respect  to  certain  business combinations.  See  "Anti-takeover
Provisions and Interested Stockholder Transactions."

Such  matters  as  take-over bids, issuer bids or  self  tenders,
going-private  transactions  and  transactions  with   directors,
officers,  significant shareholders and other related parties  to
which  Acquisition is a party will be subject  to  regulation  by
Canadian  provincial  securities legislation  and  administrative
policies of Canadian securities administrators.  Similar  matters
to  which Orbital is a party will be subject to regulation  under
United States securities laws, regulations and policies.

Orbital's Restated Certificate contains a provision that requires
the holders of two-thirds of Orbital's voting power, voting as  a
single  class,  to  approve a merger or  certain  other  business
transactions  ("Business  Combination")  between  Orbital  and  a
holder  of more than 5% of Orbital's outstanding voting stock  or
any  such  holder's affiliates or associates ("Related  Person").
Stockholder   approval  is  not  required  if  the  "fair   price
provision" (as defined therein) is satisfied or if two-thirds  of
the  "Continuing  Directors" (as defined therein)  (i)  expressly
approve  in  advance  the acquisition of stock  that  caused  the
Related Person to become a Related Person and expressly decide in
advance  of  such acquisition that the approval of two-thirds  of
the  holders  of the outstanding shares of voting  stock  is  not
required,  or (ii) approve the Business Combination.   Generally,
the  "fair price provision" will have been satisfied if the price
received  by  the holders of shares of Orbital Common  Shares  or
other  class  of voting stock is not less than the highest  price
paid  by  the  Related Person when acquiring any of  its  Orbital
Common  Shares  or  other class of voting stock,  as  applicable,
within  the two-year period preceding the earlier of the date  of
the  Business  Combination  or  the  date  of  the  first  public
announcement of the Business Combination.

Amendment to Governing Documents

Under  the CBCA, any amendment to the articles generally requires
the  approval by special resolution, which is a resolution passed
by  a  majority of not less than two-thirds of the votes cast  by
shareholders who voted in respect of that resolution.  Under  the
CBCA,  unless  the  articles or by-laws  otherwise  provide,  the
directors  may, by resolution, make, amend or repeal  any  by-law
that  regulates the business or affairs of a corporation.   Where
the  directors make, amend or repeal a by-law, they are  required
under  the CBCA to submit the by-law, amendment or repeal to  the
shareholders  at  the  next  meeting  of  shareholders,  and  the
shareholders  may confirm, reject or amend the by-law,  amendment
or repeal by an ordinary resolution, which is a resolution passed
by  a majority of the votes cast by the shareholders who voted in
respect of the resolution.

The  DGCL requires a vote of the corporation's board of directors
followed by the affirmative vote of a majority of the outstanding
stock  of  each class entitled to vote for any amendment  to  the
certificate of incorporation, unless a greater level of  approval
is  required  by the certificate of incorporation.   The  Orbital
Restated Certificate provides that any amendment that relates  to
(i)  a director's liability to Orbital or its stockholders,  (ii)
indemnification of directors, (iii) classification of  the  board
of  directors  or election or removal of directors,  (iv)  voting
requirements for approval of certain mergers, consolidations  and
other  business  combinations, or  (v)  voting  requirements  for
amendment  of  any  supermajority  voting  provisions,  must   be
approved by the affirmative vote of the holders of not less  than
two-thirds  of the outstanding shares entitled to  vote  for  the
election  of  directors.  The DGCL provides that if an  amendment
alters  the powers, preferences or special rights of a particular
class  or  series  of stock so as to affect them adversely,  that
class  or  series  shall be given the power to vote  as  a  class
notwithstanding the absence of any specifically enumerated  power
in  the  certificate  of incorporation.   The  Orbital  Series  A
Preferred  Share  which  will be issued in  connection  with  the
Arrangement  has special voting powers.  See "The  Arrangement  -
Description of Exchangeable Shares - Voting Rights."

The DGCL also states that the power to adopt, amend or repeal the
by-laws of a corporation shall be in the stockholders entitled to
vote,  provided  that  the  corporation  in  its  certificate  of
incorporation may confer such power on the board of directors  in
addition   to  the  stockholders.   Under  the  Orbital  Restated
Certificate  the board of directors has been granted this  power.
The Orbital By-laws are subject to adoption, amendment, repeal or
rescission  by a majority of the authorized number of  directors,
subject  to the right of the stockholders entitled to  vote  with
respect thereto to alter and repeal by-laws adopted by the  board
of directors.

Dissent Rights

The  CBCA  provides  that  shareholders  of  a  CBCA  corporation
entitled  to  vote  on certain matters are entitled  to  exercise
dissent  rights and to be paid the fair value of their shares  in
connection  therewith.  The CBCA does not  distinguish  for  this
purpose between listed and unlisted shares.  Such matters include
(a)  any  amalgamation with another corporation (other than  with
certain  affiliated  corporations);  (b)  an  amendment  to   the
corporation's  articles to add, change or remove  any  provisions
restricting  or constraining the issue, transfer or ownership  of
shares;  (c) an amendment to the corporation's articles  to  add,
change  or  remove any restriction on the business or  businesses
that  the  corporation may carry on or upon the powers  that  the
corporation  may exercise; (d) a continuance under  the  laws  of
another  jurisdiction; (e) a sale, lease or exchange  of  all  or
substantially all the property of the corporation other  than  in
the  ordinary course of business; (f) a court order permitting  a
shareholder to dissent in connection with an application  to  the
court  for  an  order approving an arrangement  proposed  by  the
corporation;  or  (g) certain amendments to  the  articles  of  a
corporation  which  require  a separate  class  or  series  vote,
provided  that  a shareholder is not entitled to  dissent  if  an
amendment  to the articles is effected by a court order approving
a  reorganization or by a court order made in connection with  an
action  for  an oppression remedy.  Under the CBCA, a shareholder
may, in addition to exercising dissent rights, seek an oppression
remedy  for  any  act  or  omission of  a  corporation  which  is
oppressive, unfairly prejudicial to or that unfairly disregards a
shareholder's interest.

Under the DGCL, holders of shares of any class or series have the
right,  in  certain circumstances, to dissent from  a  merger  or
consolidation by demanding payment in cash for their shares equal
to  the fair value (excluding any appreciation or depreciation as
a  consequence,  or in expectation, of the transaction)  of  such
shares, as determined by agreement with the corporation or by  an
independent  appraiser appointed by a court in an  action  timely
brought  by  the corporation or the dissenters.  The DGCL  grants
dissenters'  appraisal  rights only in the  case  of  mergers  or
consolidations  and  not in the case of a  sale  or  transfer  of
assets or a purchase of assets for stock regardless of the number
of  shares  being  issued.   Further,  no  appraisal  rights  are
available for shares of any class or series listed on a  national
securities  exchange  or designated as a national  market  system
security  on  the  NASDAQ or held of record by  more  than  2,000
stockholders,  unless  the agreement of merger  or  consolidation
converts  such shares into anything other than (a) stock  of  the
surviving corporation, (b) stock of another corporation which  is
either listed on a national securities exchange or designated  as
a national market system security on the NASDAQ or held of record
by  more  than 2,000 stockholders, (c) cash in lieu of fractional
shares, or (d) some combination of the above.  In addition,  such
rights  are  not  available  for  any  shares  of  the  surviving
corporation  if  the  merger did not  require  the  vote  of  the
stockholders of the surviving corporation.

Oppression Remedy

The CBCA provides an oppression remedy that enables the court  to
make  any  order, both interim and final, to rectify the  matters
complained  of, if the Director under the CBCA is satisfied  upon
application by a complainant (as defined below) that: (i) any act
or  omission of the corporation or an affiliate effects a result;
(ii)  the  business or affairs of the corporation or an affiliate
are  or  have been carried on or conducted in a manner; or  (iii)
the  powers  of the directors of the corporation or an  affiliate
are,  have  been or are threatened to be exercised  in  a  manner
that,  in  any of the foregoing cases, is oppressive or  unfairly
prejudicial to, or that unfairly disregards the interests of  any
security   holder,   creditor,  director  or   officer   of   the
corporation.   A  complainant includes: (a) a present  or  former
registered  holder  or  beneficial  owner  of  securities  of   a
corporation  or  any of its affiliates; (b) a present  or  former
officer  or director of the corporation or any of its affiliates;
(c) the Director under the CBCA; and (d) any other person who  in
the  discretion  of  the court is a proper person  to  make  such
application.

Because of the breadth of the conduct which can be complained  of
and  the  scope  of the court's remedial powers,  the  oppression
remedy  is  very  flexible  and  is  frequently  relied  upon  to
safeguard  the  interests of shareholders and other  complainants
with  a substantial interest in the corporation.  Under the CBCA,
it  is not necessary to prove that the directors of a corporation
acted  in  bad  faith  in  order to seek  an  oppression  remedy.
Furthermore,  the  court  may order the corporation  to  pay  the
interim  expenses of a complainant seeking an oppression  remedy,
but  the  complainant may be held accountable  for  such  interim
costs on final disposition of the complaint (as in the case of  a
derivative  action).   The DGCL does not provide  for  a  similar
remedy.

Derivative Action

Derivative actions may be brought in Delaware by a stockholder on
behalf  of,  and for the benefit of, the corporation.   The  DGCL
provides that a stockholder must aver in the complaint that he or
she  was  a  stockholder of the corporation at the  time  of  the
transaction of which he or she complains.  A stockholder may  not
sue  derivatively  unless he or she first  makes  demand  on  the
corporation that it bring suit and such demand has been  refused,
unless it is shown that such demand would have been futile.

Under the CBCA, a complainant may apply to the court for leave to
bring an action in the name of and on behalf of a corporation  or
any  subsidiary, or to intervene in an existing action  to  which
any  such  body  corporate  is  a  party,  for  the  purpose   of
prosecuting, defending or discontinuing the action on  behalf  of
the body corporate.  Under the CBCA, no action may be brought and
no  intervention  in an action may be made unless  the  court  is
satisfied that (a) the complainant has given reasonable notice to
the  directors  of  the  corporation or  its  subsidiary  of  the
complainant's intention to apply to the court if the directors of
the  corporation  or  its  subsidiary do  not  bring,  diligently
prosecute   or  defend  or  discontinue  the  action;   (b)   the
complainant is acting in good faith; and (c) it appears to be  in
the  interests  of  the corporation or its  subsidiary  that  the
action  be  brought,  prosecuted, defended  or  discontinued.   A
complainant  is  not required to give security  for  costs  in  a
derivative action.

Shareholder Consent in Lieu of Meeting

Under  the DGCL, unless otherwise provided in the certificate  of
incorporation, any action required to be taken or  which  may  be
taken  at  an  annual or special meeting of stockholders  may  be
taken without a meeting if a consent in writing is signed by  the
holders  of  outstanding stock having not less than  the  minimum
number  of votes that would be necessary to authorize such action
at  a  meeting at which all shares entitled to vote were  present
and  voted.  The Orbital Restated Certificate does not permit any
action  to  be  taken  by  written  consent.   Under  the   CBCA,
shareholder action without a meeting may only be taken by written
resolution  signed by all shareholders who would be  entitled  to
vote thereon at a meeting.

Director Qualifications

A  majority of the directors of a CBCA corporation generally must
be resident Canadians.  The CBCA also requires that a corporation
whose  securities are publicly traded must have  not  fewer  than
three  directors,  at  least two of  whom  are  not  officers  or
employees  of the corporation or its affiliates.  The  DGCL  does
not have comparable requirements.

Fiduciary Duties of Directors

Directors  of  corporations incorporated or organized  under  the
CBCA  and  the DGCL have fiduciary obligations to the corporation
and  its  shareholders.  Pursuant to these fiduciary obligations,
the directors must act in accordance with the so-called duties of
"due  care"  and  "loyalty."  Under the DGCL, the  duty  of  care
requires  that the directors act in an informed and  deliberative
manner   and  inform  themselves,  prior  to  making  a  business
decision,  of  all material information available to  them.   The
duty  of  loyalty may be summarized as the duty to  act  in  good
faith,  not  out  of  self-interest, and in a  manner  which  the
directors reasonably believe to be in the best interests  of  the
stockholders.

Pursuant to section 122 of the CBCA, the duty of loyalty requires
directors of a CBCA corporation to act honestly and in good faith
with  a  view to the best interests of the corporation,  and  the
duty  of  care  requires that the directors  exercise  the  care,
diligence  and  skill  that  a reasonably  prudent  person  would
exercise in comparable circumstances.

Indemnification of Officers and Directors

Under  the  CBCA  and  pursuant  to  the  MDA  By-Laws  and   the
Acquisition By-Laws, MDA and Acquisition may indemnify a director
or  officer, a former director or officer or a person who acts or
acted at the corporation's request as a director or officer of  a
body  corporate of which MDA or Acquisition, as the case may  be,
is  or  was  a shareholder or creditor, and his or her heirs  and
legal  representatives (an "Indemnifiable Person"),  against  all
costs,  charges and expenses, including an amount paid to  settle
an  action or satisfy a judgment, reasonably incurred by  him  or
her in respect of any civil, criminal or administrative action or
proceeding to which he or she is made a party by reason of  being
or  having  been a director or officer of MDA or Acquisition,  as
the  case may be, or such body corporate, if: (a) he or she acted
honestly  and in good faith with a view to the best interests  of
MDA;  and (b) in the case of a criminal or administrative  action
or  proceeding that is enforced by a monetary penalty, he or  she
had  reasonable grounds for believing that his or her conduct was
lawful.   An  Indemnifiable Person is entitled to such  indemnity
from the corporation if he or she was substantially successful on
the  merits in his or her defence of the action or proceeding and
fulfilled  the  conditions set out in  (a)  and  (b),  above.   A
corporation may, with the approval of a court, also indemnify  an
Indemnifiable Person in respect of an action by or on  behalf  of
the  corporation or such body corporate to procure a judgment  in
its  favour,  to which such person is made a party by  reason  of
being  or having been a director or an officer of the corporation
or body corporate, if he or she fulfils the conditions set out in
(a) and (b), above.

The  DGCL  provides that a corporation may indemnify its  present
and  former  directors, officers, employees and agents  (each  an
"indemnitee")   against   all  reasonable   expenses   (including
attorneys' fees) and, except in actions initiated by  or  in  the
right  of  the  corporation, against  all  judgments,  fines  and
amounts  paid in settlement in actions brought against  them,  if
such  indemnitee acted in good faith and in a manner which he  or
she  reasonably believed to be in, or not opposed  to,  the  best
interests  of  the  corporation, and in the case  of  a  criminal
proceeding, had no reasonable cause to believe that  his  or  her
conduct  was  unlawful.   The  corporation  shall  indemnify   an
indemnitee  to  the  extent that he or she is successful  on  the
merits  or otherwise in the defence of any claim, issue or matter
associated  with  an  action.  The Orbital  Restated  Certificate
provides  for  indemnification of directors or  officers  to  the
fullest extent permitted by the DGCL.

The  DGCL  allows  for  the advance payment  of  an  indemnitee's
expenses  prior  to the final disposition of an action,  provided
that  the indemnitee undertakes to repay any such amount advanced
if  it is later determined that the indemnitee is not entitled to
indemnification with regard to the action for which such expenses
were  advanced.   The CBCA does not expressly  provide  for  such
advance payment.

Director Liability

The DGCL provides that the charter of the corporation may include
a provision which limits or eliminates the liability of directors
to  the corporation or its stockholders for monetary damages  for
breach  of  fiduciary duty as a director, provided such liability
does not arise from certain proscribed conduct, including acts or
omissions   not  in  good  faith  or  which  involve  intentional
misconduct or a knowing violation of law, breach of the  duty  of
loyalty,  the  payment of unlawful dividends  or  expenditure  of
funds for unlawful stock purchases or redemptions or transactions
from  which  such director derived an improper personal  benefit.
The  Orbital  Restated Certificate contains a provision  limiting
the liability of its directors to the fullest extent permitted by
the  DGCL.   The  CBCA does not permit any such limitation  of  a
director's liability.

Anti-takeover Provisions and Interested Stockholder Transactions

The   DGCL  prohibits,  in  certain  circumstances,  a  "business
combination"   between  the  corporation   and   an   "interested
stockholder"  within three years of the stockholder  becoming  an
"interested  stockholder."   An  "interested  stockholder"  is  a
holder  who, directly or indirectly, controls 15% or more of  the
outstanding  voting stock or is an affiliate of  the  corporation
and  was the owner of 15% or more of the outstanding voting stock
at  any  time  within the prior three-year period.   A  "business
combination" includes a merger or consolidation, a sale or  other
disposition of assets having an aggregate market value of 10%  or
more  of  the  consolidated  assets of  the  corporation  or  the
aggregate   market  value  of  the  outstanding  stock   of   the
corporation  and  certain transactions that  would  increase  the
interested  stockholder's proportionate share  ownership  in  the
corporation.  This provision does not apply where: (i) either the
business  combination or the transaction which  resulted  in  the
stockholder becoming an interested stockholder is approved by the
corporation's board of directors prior to the date the interested
stockholder   acquired   such  15%  interest;   (ii)   upon   the
consummation of the transaction which resulted in the stockholder
becoming  an  interested stockholder, the interested  stockholder
owned  at  least  85%  of the outstanding  voting  stock  of  the
corporation excluding, for the purpose of determining the  number
of  shares  outstanding, shares held by persons who are directors
and   also  officers  and  by  employee  stock  plans  in   which
participants  do  not have the right to determine  confidentially
whether  shares held subject to the plan will be tendered,  (iii)
the  business combination is approved by a majority of the  board
of  directors  and  the  affirmative vote of  two-thirds  of  the
outstanding   votes   entitled  to  be  cast   by   disinterested
stockholders   at  an  annual  or  special  meeting;   (iv)   the
corporation does not have a class of voting stock that is  listed
on a national securities exchange, authorized for quotation on an
inter-dealer quotation system of a registered national securities
association,  or  held of record by more than 2,000  stockholders
unless  any of the foregoing results from action taken,  directly
or indirectly, by an interested stockholder or from a transaction
in  which a person becomes an interested stockholder, or (v)  the
corporation  has  opted out of this provision.  Orbital  has  not
opted out of this provision.

The CBCA does not contain a comparable provision with respect  to
"business  combinations"  however policies  of  certain  Canadian
securities  regulatory authorities, including Policy 9.1  of  the
Ontario    Securities   Commission   ("Policy   9.1"),    contain
requirements  in  connection with related party transactions.   A
related  party  transaction means, generally, any transaction  by
which an issuer, directly or indirectly, acquires or transfers an
asset  or  acquires or issues treasury securities or  assumes  or
transfers  a liability from or to, as the case may be, a  related
party  by any means in any one transaction or any combination  of
transactions.   "Related  party" is  defined  in  Policy  9.1  to
include directors, senior officers and holders of at least 10% of
the voting securities of the issuer.

Policy  9.1  requires  more  detailed disclosures  in  the  proxy
material  sent to security holders in connection with  a  related
party  transaction.   Where  the value  of  the  asset,  treasury
security or the principal amount of the liability, subject to the
related  party  transactions exceeds 25% of the  issuer's  market
capitalization,  subject  to  certain  exceptions,   Policy   9.1
requires  the  preparation of a formal valuation of  the  subject
matter   of  the  related  party  transaction  and  any  non-cash
consideration offered therefor and the inclusion of a summary  of
the   valuation  in  the  proxy  material.   For  related   party
transactions of such value, Policy 9.1 also requires, subject  to
certain exemptions, that the minority shareholders of the  issuer
approve  the  transaction, by either a simple  majority  or  two-
thirds of the votes cast, depending upon the circumstances.

Shareholder Protection Rights Plan

MDA  has  a  Shareholder Protection Rights Plan.  The Shareholder
Protection   Rights  Plan  in  certain  specific   circumstances,
including the event of a hostile takeover bid being made for MDA,
provides that each MDA Common Shareholder is entitled to  acquire
MDA  Common Shares, or in certain circumstances common shares  of
the  bidder,  at  a 50% discount from the then prevailing  market
price.    The  MDA  Board  has  waived  the  provisions  of   the
Shareholder  Protection  Rights Plan to permit  the  transactions
contemplated   by   the  Arrangement  to  be  completed   without
triggering such provisions.

Orbital does not currently have a plan similar to the Shareholder
Protection  Rights  Plan,  although  plans  comparable   to   the
Shareholder Protection Rights Plan are permitted by the DGCL  and
may  be  adopted  by  a  board of directors  without  shareholder
approval.   Orbital may in the future adopt a shareholder  rights
plan.


                       DISSENTING RIGHTS

Pursuant  to  the Interim Order, MDA Shareholders  and  MDA  1988
Optionholders have been provided with the right to  dissent  from
the   Arrangement   Resolution  under  and  in  compliance   with
section 190 of the CBCA and the Interim Order, reprinted in their
entireties as Appendices "D" and "G", respectively to this  Proxy
Circular.  The following summary is qualified in its entirety  by
the Interim Order and the provisions of section 190 of the CBCA.

Pursuant  to  the Interim Order, a MDA Shareholder  who  dissents
from the Arrangement Resolution in compliance with section 190 of
the  CBCA  and the Interim Order (a "Dissenting MDA Shareholder")
will be entitled, in the event the Arrangement becomes effective,
to be paid by MDA the fair value of the MDA Common Shares held by
such  Dissenting MDA Shareholder determined as of  the  close  of
business on the day before the Arrangement Resolution is adopted.

Pursuant  to  the Interim Order and the Plan of Arrangement,  any
MDA   1988   Optionholder  who  dissents  from  the   Arrangement
Resolution  in accordance with section 190 of the  CBCA  and  the
Interim  Order (a "Dissenting MDA 1988 Optionholder"),  shall  be
deemed,  pursuant  to  the Plan of Arrangement  and  the  Interim
Order,  to  have exercised the MDA 1988 Options with  respect  to
which  he or she is exercising the dissent.  Such Dissenting  MDA
1988  Optionholder, will be entitled, if the Arrangement  becomes
effective,  to  be paid the fair value of the MDA  Common  Shares
deemed to have been issued upon exercise, set-off by the exercise
price.   The  fair value shall be determined as of the  close  of
business on the day before the Arrangement Resolution is adopted.

A  MDA Shareholder or MDA 1988 Optionholder who wishes to dissent
must  send  to MDA, no later than the termination of the  Special
Meeting  (or any adjournment thereof), written objection  to  the
Arrangement Resolution (a "Dissent Notice") and must not vote for
the  Arrangement Resolution.  The filing of a Dissent Notice does
not  deprive a MDA Shareholder or a MDA 1988 Optionholder, as the
case  may  be, of the right to vote.  The CBCA does not  provide,
and  MDA  will  not assume, that a vote against  the  Arrangement
Resolution  or an abstention constitutes a Dissent Notice  but  a
MDA  Shareholder or a MDA 1988 Optionholder need not vote his  or
her  MDA  Common Shares or the votes to be exercised with respect
to his or her MDA 1988 Options against the Arrangement Resolution
in  order  to  dissent.  Under the CBCA, there  is  no  right  of
partial dissent and, accordingly, a Dissenting MDA Shareholder or
a  Dissenting MDA 1988 Optionholder, as the case may be, may only
dissent  with respect to all MDA Common Shares or all MDA  Common
Shares to which he or she is entitled under all MDA 1988 Options,
respectively, held by him or her on behalf of any one  beneficial
owner and which are registered in the name of the Dissenting  MDA
Shareholder or Dissenting MDA 1988 Optionholder, as the case  may
be.

MDA  is required, within 10 days after the Arrangement Resolution
is   adopted,  to  notify  each  MDA  Shareholder  or  MDA   1988
Optionholder  or  MDA 1988 Optionholder who has filed  a  Dissent
Notice that the Arrangement Resolution has been adopted, but such
notice  is  not  required to be sent to any MDA  Shareholder  who
voted for the Arrangement Resolution or who has withdrawn his  or
her Dissent Notice.

A   Dissenting   MDA  Shareholder  or  a  Dissenting   MDA   1988
Optionholder  must then, within 20 days after receipt  of  notice
that the Arrangement Resolution has been adopted or, if he or she
does  not  receive such notice, within 20 days after  he  or  she
learns that the Arrangement Resolution has been adopted, send  to
MDA  a written notice (a "Payment Demand") containing his or  her
name  and address, the number of MDA Common Shares in respect  of
which  he  or she dissents, and a demand for payment of the  fair
value of such MDA Common Shares.  Within 30 days after sending  a
Payment Demand, the Dissenting MDA Shareholder must send  to  the
MDA  transfer agent the certificates representing the MDA  Common
Shares in respect of which he or she dissents.  A Dissenting  MDA
1988 Optionholder shall be deemed to have sent those certificates
to the MDA transfer agent by reason of the deemed exercise of the
MDA  1988  Option.  A Dissenting MDA Shareholder or a  Dissenting
MDA  1988  Optionholder  who fails to send  to  MDA,  within  the
appropriate time frame, certificates representing the MDA  Common
Shares  in respect of which he or she dissents, forfeits  his  or
her  right  to make a claim in accordance with the provisions  of
section 190 of the CBCA.  The MDA transfer agent will endorse  on
share  certificates received from a Dissenting MDA Shareholder  a
notice  that the holder is a Dissenting MDA Shareholder and  will
forthwith  return  the share certificates to the  Dissenting  MDA
Shareholder.

On  sending a Payment Demand to MDA, a Dissenting MDA Shareholder
or  a  Dissenting MDA 1988 Optionholder ceases to have any rights
as  a  MDA  Shareholder or MDA 1988 Optionholder, other than  the
right  to be paid the fair value of his or her MDA Common  Shares
as determined under section 190 of the CBCA, except where:

(a)  the  Dissenting  MDA  Shareholder or a Dissenting  MDA  1988
     Optionholder withdraws his or her Payment Demand before  MDA
     makes an offer to him or her pursuant to the CBCA;

(b)  MDA  fails to make an offer as hereinafter described and the
     Dissenting  MDA  Shareholder  or  the  Dissenting  MDA  1988
     Optionholder withdraws his or her Payment Demand; or

(c)  the Arrangement does not proceed;

in  which  case his or her rights as a MDA Shareholder or  a  MDA
1988  Optionholder, as the case may be, are reinstated as of  the
date he or she sent the Payment Demand.

MDA is required, not later than seven days after the later of the
Effective  Date  or  the date on which MDA received  the  Payment
Demand  of a Dissenting MDA Shareholder or a Dissenting MDA  1988
Optionholder, as the case may be, to send to each such dissenting
person  who  has  sent a Payment Demand a written  offer  to  pay
("Offer  to  Pay")  for his or her MDA Common  Shares  an  amount
considered by the MDA Board to be the fair value thereof, on  the
close of business on the day before the Arrangement Resolution is
adopted,  accompanied by a statement showing the manner in  which
the fair value was determined.  Every Offer to Pay must be on the
same  terms.   MDA  must  pay for the  MDA  Common  Shares  of  a
Dissenting  MDA Shareholder or a Dissenting MDA 1988 Optionholder
within  10 days after an Offer to Pay made as aforesaid has  been
accepted by a Dissenting MDA Shareholder or a Dissenting MDA 1988
Optionholder, but any such Offer to Pay lapses if  MDA  does  not
receive  an acceptance thereof within 30 days after the Offer  to
Pay has been made.

If  MDA  fails  to  make  an Offer to Pay for  a  Dissenting  MDA
Shareholder's or a Dissenting MDA 1988 Optionholder's MDA  Common
Shares,  or  if a Dissenting MDA Shareholder or a Dissenting  MDA
1988  Optionholder fails to accept an Offer to Pay which has been
made,  MDA may, within 50 days after the Effective Date or within
such further period as a court may allow, apply to a court having
jurisdiction in the place where MDA has its registered office  or
in   the  Province  where  such  Dissenting  MDA  Shareholder  or
Dissenting  MDA  1988  Optionholder resides  if  MDA  carries  on
business in that province, to fix a fair value for the MDA Common
Shares  of  Dissenting MDA Shareholders or  Dissenting  MDA  1988
Optionholders.   If  MDA fails to apply to a  court  within  such
period,  a  Dissenting  MDA Shareholder or  Dissenting  MDA  1988
Optionholder may apply to a court for the same purpose  within  a
further  period  of 20 days or within such further  period  as  a
court may allow.  A Dissenting MDA Shareholder or Dissenting  MDA
1988  Optionholder is not required to give security for costs  in
such an application.

Upon  an  application to a court, all Dissenting MDA Shareholders
and all Dissenting MDA 1988 Optionholders whose MDA Common Shares
have  not  been  purchased by MDA will be joined as  parties  and
bound  by the decision of the court, and MDA will be required  to
notify  each  affected Dissenting MDA Shareholder and  Dissenting
MDA  1988 Optionholder of the date, place and consequences of the
application  and of his or her right to appear and  be  heard  in
person or by counsel.  Upon any such application to a court,  the
court  may determine whether any other Dissenting MDA Shareholder
or  Dissenting MDA 1988 Optionholder should be joined as a party,
and  the  court  will then fix a fair value for  the  MDA  Common
Shares of all Dissenting MDA Shareholders or Dissenting MDA  1988
Optionholders who have not accepted an Offer to Pay.   The  final
order  of a court will be rendered against MDA in favour of  each
such   Dissenting  MDA  Shareholder  and  Dissenting   MDA   1988
Optionholder and for the amount of the fair value of his  or  her
MDA  Common Shares as fixed by the court.  The court may, in  its
discretion,  allow a reasonable rate of interest  on  the  amount
payable  to  each such Dissenting MDA Shareholder and  Dissenting
MDA  1988 Optionholder from the Effective Date until the date  of
payment.

The  above  is  only  a  summary of  the  dissenting  shareholder
provisions of the CBCA and the Interim Order, which are technical
and  complex.   It is suggested that any MDA Shareholder  or  MDA
1988  Optionholder wishing to avail himself or herself of his  or
her  rights  under  those provisions seek his or  her  own  legal
advice  as failure to comply strictly with the provisions of  the
CBCA  and  the  Interim Order may prejudice his or her  right  of
dissent.    For   a  general  summary  of  certain   income   tax
implications  to  a Dissenting MDA Shareholder, see  "Income  Tax
Considerations to MDA Shareholders and Optionholders  -  Canadian
Federal  Income Tax Considerations - Dissenting MDA Shareholders,
and  "-  Dissenting MDA 1988 Optionholders" and "- United  States
Federal Income Tax Considerations - Dissenting Persons."


                     AVAILABLE INFORMATION

Orbital is subject to the informational requirements of the  1934
Securities  Exchange  Act,  and  in  accordance  therewith  files
reports  and  other information with the SEC.  Such  reports  and
other  information filed with the SEC can be inspected and copied
at  the public reference facilities maintained by the SEC at Room
1024, 450 Fifth Street, N.W., Washington, D.C. 20549, and at  the
SEC's  Regional Offices at Seven World Trade Center, 13th  Floor,
New  York, New York 10048 and Northwest Atrium Center,  500  West
Madison  Street, Suite 1400, Chicago, Illinois 60661.  Copies  of
such  material  also  can be obtained from the  Public  Reference
Section  of the SEC, Washington, D.C. 20549 at prescribed  rates.
In  addition, material filed by Orbital can be inspected  at  the
offices  of  The  Nasdaq Stock Market, Reports  Section,  1735  K
Street N.W., Washington, D.C., 20006.


                         LEGAL MATTERS

Certain legal matters in connection with the Arrangement will  be
passed  upon  by Farris, Vaughan, Wills & Murphy,  Vancouver  and
Paul,  Weiss, Rifkind, Wharton & Garrison, New York, New York  on
behalf  of  MDA  and  by Ropes & Gray, Boston, Massachusetts  and
Davies,   Ward  &  Beck,  Toronto  on  behalf  of   Orbital   and
Acquisition.


      APPROVAL OF PROXY CIRCULAR BY MDA BOARD OF DIRECTORS

The  contents of this Proxy Circular and the sending  thereof  to
MDA Shareholders and MDA 1988 Optionholders has been approved  by
the MDA Board.

DATED  at  Richmond, British Columbia, this 6th day  of  October,
1995.


                               BY ORDER OF THE BOARD OF DIRECTORS


                                        /S/ Robert B. Wallis

                                      ROBERT B. WALLIS, Secretary