ORBITAL SCIENCES CORPORATION
       1990 STOCK OPTION PLAN FOR NON-EMPLOYEE DIRECTORS


                           ARTICLE I
                        PURPOSE OF PLAN

           The  purpose  of  this  1990  Stock  Option  Plan  for
Non-Employee Directors is to promote the growth and profitability
of   Orbital  Sciences  Corporation  by  providing,  through  the
ownership  of  Shares,  incentives to  attract  and  retain  non-
employee  directors  who are in a position  to  make  significant
contributions   to   the  success  of  the  Company   and   other
Participating  Companies and to reward such  directors  for  such
contributions.


                           ARTICLE II
                          DEFINITIONS

          For the purposes of the Plan, the following terms shall
have the meanings set forth in this Article II:

      2.01   Board.   The term "Board" shall mean  the  Board  of
Directors of the Company.

       2.02   Committee.   The  term  "Committee"  shall  mean  a
committee  appointed by the Board pursuant to  Section  3.04  and
constituting not less than three (3) members of the Board.

      2.03   Company.   The  term "Company"  shall  mean  Orbital
Sciences  Corporation, a Delaware corporation, or  any  successor
thereof.

      2.04  Director.  The term "Director" shall mean a member of
the  Board,  or  a  member  of  the board  of  directors  of  any
Participating Company.

      2.05  Effective Date.  The term "Effective Date" shall mean
August 2, 1990.

     2.06  Eligible Director.  The term "Eligible Director" shall
mean  any Director who is not an employee of the Company  or  any
Participating  Company  and is not a  holder  of  more  than  two
percent  (2%) of the outstanding Shares, nor a person who  is  an
affiliate of any such holder.

      2.07  Exchange Act.  The term "Exchange Act" shall mean the
Securities Exchange Act of 1934, as amended.

     2.08  Fair Market Value.  The term "Fair Market Value," when
used  with  respect to the determination of the option  price  of
Options, shall mean the closing sale price of outstanding  Shares
on  the  national securities exchange on which outstanding Shares
are  then principally traded or, if that measure of price is  not
available,  on a composite index of such exchanges  or,  if  that
measure of price is not available, in a national market system on
which  outstanding Shares are quoted on the date of the grant  of
the  Option.  In the event that there are no sales of outstanding
Shares  on any such exchange or market on such date of the  grant
of the Option, the fair market value of Shares on the date of the
grant  shall be deemed to be the closing sales price on the  next
preceding day on which outstanding Shares were sold on  any  such
exchange  or market.  In the event that Shares are not listed  or
quoted  on any such exchange or market on such date of the  grant
of the Option, a reasonable valuation of the fair market value of
the Shares on the date of the grant shall be made by the Board.

      2.09   I.R.C.   The term "I.R.C." shall mean  the  Internal
Revenue Code of 1986, as it has been or may be amended from  time
to time.

      2.10   Incentive  Stock Option.  The term "Incentive  Stock
Option"   shall   mean  any  Option  intended  to   satisfy   the
requirements  under I.R.C. Section 422(b) as an  incentive  stock
option.

      2.11   Nonstatutory  Stock Option.  The term  "Nonstatutory
Stock  Option" shall mean any Option granted under the Plan  that
does not qualify as an Incentive Stock Option.

      2.12   Option.  The term "Option" shall mean an  option  to
acquire Shares granted under the Plan.

      2.13  Optionee.  The term "Optionee" shall mean an Eligible
Director who has been granted Options.

      2.14   Parent  Corporation.  The term "Parent  Corporation"
shall mean a corporation as defined in I.R.C. Section 425(e).

       2.15   Participating  Company.   The  term  "Participating
Company"  shall  mean the Company and any Parent  Corporation  or
Subsidiary Corporation.

      2.16   Plan.  The term "Plan" shall refer to the 1990 Stock
Option  Plan for Non-Employee Directors of the Company set  forth
herein  that  provides  for the granting  of  Nonstatutory  Stock
Options.

      2.17  Securities Act.  The term "Securities Act" shall mean
the Securities Act of 1933, as amended.

      2.18   Shares.  The term "Shares" shall mean shares of  the
Company's  authorized Common Stock, $0.01 par value, and  may  be
unissued  shares  or  treasury shares  or  shares  purchased  for
purposes of the Plan.

       2.19    Subsidiary  Corporation.   The  term   "Subsidiary
Corporation"  shall  mean  a corporation  as  defined  in  I.R.C.
Section 425(f).

       2.20   Terminating  Transaction.   The  term  "Terminating
Transaction"  shall mean any of the following  events:   (a)  the
dissolution  or liquidation of the Company; (b) a reorganization,
merger  or  consolidation of the Company with one or  more  other
corporations  as  a  result of which  the  Company  goes  out  of
existence  or becomes a subsidiary of another corporation  (which
shall  be  deemed  to have occurred if another corporation  shall
own, directly or indirectly, eighty percent (80%) or more of  the
aggregate  voting power of all outstanding equity  securities  of
the  Company);  (c) a sale of substantially all of the  Company's
assets;  or  (d)  a sale to one person (or two  or  more  persons
acting   in   concert)  of  equity  securities  of  the   Company
representing eighty percent (80%) or more of the aggregate voting
power  of  all outstanding equity securities of the Company.   As
used  herein  or elsewhere in this Plan, the word "person"  shall
mean  an  individual,  corporation, partnership,  association  or
other  person  or  entity, or any group of two  or  more  of  the
foregoing that have agreed to act together.

      2.21   Termination Date.  The term "Termination Date" shall
mean August 2, 2000.

      2.22   Total Disability.  The term "Total Disability" shall
mean a total and permanent disability as that term is defined  in
I.R.C. Section 22(e)(3).


                          ARTICLE III
                     ADMINISTRATION OF PLAN

       3.01    Administration  by  Board.   The  Plan  shall   be
administered  by  the  Board.  The  Board  shall  have  full  and
absolute power and authority in its sole discretion (a) to  grant
Options in accordance with the Plan to Eligible Directors; (b) to
prescribe the form or forms of instruments evidencing Options and
any  other instruments required under the Plan and to change such
forms  from  time to time; (c) to adopt, amend and rescind  rules
and  regulations for the administration of the Plan; and  (d)  to
interpret  the  Plan and to decide any questions and  settle  all
controversies and disputes that may arise in connection with  the
Plan.

     3.02  Rules and Regulations.  The Board may adopt such rules
and regulations as the Board may deem necessary or appropriate to
carry out the purposes of the Plan and shall have authority to do
everything necessary or appropriate to administer the Plan.

      3.03   Binding  Authority.  All decisions,  determinations,
interpretations  or other actions by the Board  shall  be  final,
conclusive and binding on all parties and on their successors-in-
interest.

      3.04  Administration by Committee.  The Board, in its  sole
discretion,  may,  from  time to time,  appoint  a  Committee  to
administer the Plan and exercise all of the powers, authority and
discretion of the Board under the Plan, other than the power  and
authority to amend and terminate the Plan under Section 7.01.


                           ARTICLE IV
              NUMBER OF SHARES AVAILABLE FOR GRANT

            Subject  to  the provisions of this  Article  IV  and
Section 6.08(a), the maximum aggregate number of Shares which may
be  optioned  and sold under the Plan is 170,000.  In  the  event
that outstanding Options shall, for any reason, terminate, lapse,
be  forfeited  or  expire  without being  exercised,  the  Shares
subject to such unexercised Options shall again be available  for
the  granting  of  Options.  In the event that Shares  that  were
previously  issued by the Company upon exercise of an Option  are
reacquired  by the Company as part of the consideration  received
(in  accordance with Section 6.05(b) hereof) upon the  subsequent
exercise  of  an  Option, such reacquired Shares shall  again  be
available for the granting of Options.


                           ARTICLE V
                          TERM OF PLAN

            The  Plan shall be effective as of the Effective Date
and  shall terminate on the Termination Date.  No Option  may  be
granted after the Termination Date.


                           ARTICLE VI
                          OPTION TERMS

     6.01  Number of Options Shares and Form of Option Agreement.
Each  Eligible  Director shall be granted  a  Nonstatutory  Stock
Option  for  two thousand (2,000) Shares on August 2,  1991.   In
addition,  each Eligible Director shall be granted a Nonstatutory
Stock  Option for two thousand (2,000) Shares on January 2,  1991
and  on each anniversary thereafter through January 2, 1995,  and
three  thousand  (3,000) Shares on January 2, 1996  and  on  each
anniversary thereafter, provided that such individual is then  an
Eligible Director.  Any Option granted shall be evidenced  by  an
agreement ("Option Agreement") in such form as the Board, in  its
discretion,  may,  from  time  to  time,  approve.   Any   Option
Agreement  shall contain such terms and conditions as  the  Board
may  deem necessary or appropriate and which are not inconsistent
with the provisions of the Plan.

      6.02  Option Exercise Price.  The option exercise price for
Shares  covered by Options shall be the Fair Market Value of  the
Shares.

     6.03  Vesting and Exercisability of Options.  Subject to the
limitations  set  forth  herein and/or in any  applicable  Option
Agreement entered into hereunder, Options granted shall vest  and
be  exercisable in accordance with the rules set  forth  in  this
Section 6.03:

            (a) General.  Subject to the other provisions of this
Section  6.03,  Options  shall vest  and  become  exercisable  in
accordance with the following formula:

                 (i)  Options  granted on August  2,  1990  shall
     become  exercisable  to the extent of  one  hundred  percent
     (100%) of the Shares covered thereby on January 2, 1991; and

                (ii)  Options granted after August 2, 1990  shall
     become  exercisable as to one hundred percent (100%) of  the
     Shares covered thereby on the first anniversary of the  date
     of grant.

            (b)  Termination of Options.  All installments of  an
Option  shall  expire and terminate ten (10) years from  the  day
before  the date such Option was granted (the "Option Termination
Date").

           (c) Termination of Directorship other than by Death or
Total Disability.  In the event that an Optionee ceases to  be  a
Director  for  any reason (other than death or Total Disability),
any Options held by such Optionee that have not vested and become
exercisable as of the directorship termination date shall  expire
and become unexercisable as of the directorship termination date.
All  vested  and  exercisable  Options  as  of  the  directorship
termination date shall expire and become unexercisable as of  the
earlier  of  (i)  three  (3)  months following  the  directorship
termination  date  or (ii) the original Option Termination  Date.
For  purposes of the Plan, an Optionee who is a Director  of  any
Participating  Company shall not be deemed  to  have  incurred  a
termination  of his directorship so long as such  Optionee  is  a
Director of any Participating Company.

            (d)  Death  or Total Disability of Optionee  while  a
Director.  In the event that the directorship of an Optionee with
a Participating Company is terminated by reason of death or Total
Disability,  any  vested and exercisable  Options  held  by  such
Optionee shall expire and become unexercisable as of the  earlier
of  (i) the applicable Option Termination Date or (ii) the  first
anniversary  of the date of termination of directorship  of  such
Optionee by reason of the Optionee's death or Total Disability.

            Any  such  vested  and  exercisable  Options  may  be
exercised prior to their expiration only by the person or persons
to  whom the Optionee's Option rights pass by will or the laws of
descent and distribution.  Any Options held by such a deceased or
disabled Optionee that are not vested and exercisable as  of  the
date  of the Director's termination of directorship due to  death
or  Total Disability shall expire and become unexercisable as  of
the directorship termination date.

             (e)  Termination  of  Affiliation  of  Participating
Company.   Notwithstanding  the  foregoing  provisions  of   this
Section 6.03, in the case of an Optionee who is a Director  of  a
Participating Company other than the Company, upon an Affiliation
Termination  (as  defined herein) of such Participating  Company,
such  Optionee shall be deemed (for all purposes of the Plan)  to
have incurred a termination of his directorship for reasons other
than  death  or  Total Disability, with such  termination  to  be
deemed  effective  as of the effective date of  said  Affiliation
Termination.   As used herein, the term "Affiliation Termination"
shall  mean,  with  respect  to  a  Participating  Company,   the
termination   of  such  Participating  Company's  status   as   a
Participating Company.

      6.04   Exercise of Options.  Options may be  exercised,  in
whole  or  in part, by giving written notice of exercise  to  the
Company,  which notice shall specify the number of Shares  to  be
purchased  and  shall be accompanied by payment in  full  of  the
purchase price in accordance with Section 6.05.  An Option  shall
be deemed exercised when such written notice of exercise has been
received  by the Company.  No Shares shall be issued  until  full
payment  has been made and the Optionee has satisfied such  other
conditions as may be required by the Plan, as may be required  by
applicable  laws, rules or regulations, or as may be  adopted  or
imposed  by the Board.  Until the issuance of stock certificates,
no  right to vote or receive dividends or any other rights  as  a
stockholder   shall  exist  with  respect  to   optioned   Shares
notwithstanding  the exercise of the Option.  No adjustment  will
be  made for a dividend or other right for which the record  date
is  prior to the date the stock certificate is issued, except  as
provided in Section 6.08(a).



     6.05  Payment of Option Exercise Price.

            (a)  Except as otherwise provided in Section 6.05(b),
the  entire option exercise price shall be paid at the  time  the
Option  is  exercised by cashier's check or such other  means  as
deemed acceptable by the Company.

            (b)  An Optionee may elect to pay for all or some  of
the  Optionee's  Shares with Shares to which the Optionee  has  a
right  at  the  time  of the exercise by the Optionee,  including
Shares  to  which the Optionee has obtained a right  by  previous
exercise,   subject  to  all  restrictions  and  limitations   of
applicable  laws,  rules  and  regulations  and  subject  to  the
satisfaction  of any conditions the Board may impose,  including,
but  not  limited  to,  the  making of such  representations  and
warranties  and the providing of such other assurances  that  the
Board  may  require with respect to the Optionee's title  to  the
Shares  used  for  payment of the exercise price.   Such  payment
shall  be  made by delivery of certificates representing  Shares,
duly  endorsed  or  with duly signed stock power  attached,  such
Shares to be valued at the last reported sale price of the Shares
on  a  national securities exchange or national market system  on
the  date  immediately preceding the day notice  of  exercise  is
received by the Company or, if such Shares are not then listed or
quoted on such an exchange or market, on such basis as the  Board
shall determine.

      6.06  Options Not Transferable.  Options granted under  the
Plan   may   not   be  sold,  pledged,  hypothecated,   assigned,
encumbered, gifted or otherwise transferred or alienated  in  any
manner, either voluntarily or involuntarily by operation of  law,
other  than by will or the laws of descent and distribution,  and
may  be exercised during the lifetime of an Optionee only by such
Optionee.

     6.07  Restrictions on Issuance of Shares.

            (a)  No  Shares  shall be issued  or  delivered  upon
exercise  of  an  Option unless and until there shall  have  been
compliance  with  all applicable requirements of  the  Securities
Act,  all  applicable  listing  or similar  requirements  of  any
national  securities exchange or national market system on  which
Shares  are  then listed or quoted, and any other requirement  of
law  or  of  any  regulatory body having jurisdiction  over  such
issuance  and delivery.  The inability of the Company  to  obtain
any  required permits, authorizations or approvals necessary  for
the  lawful  issuance and sale of any Shares hereunder  on  terms
deemed  reasonable by the Board shall relieve  the  Company,  the
Board  and any Committee of any liability in respect of the  non-
issuance  or  sale  of  such Shares as to  which  such  requisite
permits,   authorizations  or  approvals  shall  not  have   been
obtained.

            (b) As a condition to the granting or exercise of any
Option,  the Board may require the person receiving or exercising
such  Option  to make any representation and/or warranty  to  the
Company  as  may  be  required  under  any  applicable   law   or
regulation, including, but not limited to, a representation  that
the  Option  and/or Shares are being acquired only for investment
and  without  any  present intention to sell or  distribute  such
Option and/or Shares, if such a representation is required  under
the  Securities  Act  or  any  other  applicable  law,  rule   or
regulation.

           (c) The grant of Options prior to approval of the Plan
by  the affirmative vote or written consent of a majority of  the
holders of outstanding Shares represented and voting at a meeting
or  by  written  consent is conditioned on  such  approval  being
obtained  within twelve (12) months of the adoption of the  Plan.
In  the  event  such stockholder approval is not obtained  within
such time period, any outstanding Options shall be void.

     6.08  Option Adjustments.

             (a)   If   the  outstanding  Shares  are  increased,
decreased,  changed into or exchanged for a different  number  or
kind   of   shares   of   the  Company  through   reorganization,
recapitalization, reclassification, stock dividend,  stock  split
or  reverse  stock  split, upon authorization  of  the  Board,  a
proportionate adjustment shall be made in the number or  kind  of
shares  and  the  per-share option price thereof,  which  may  be
issued in the aggregate and to individual Optionees upon exercise
of  Options; provided, however, that no such adjustment  need  be
made  if,  upon the advice of counsel, the Board determines  that
such  adjustment  may result in the receipt of federally  taxable
income to holders of outstanding Options or the holders of Common
Stock or other classes of the Company's securities.

            (b) In the event of any Terminating Transaction,  all
outstanding  Options  shall  become  exercisable  prior  to   the
consummation of such Terminating Transaction and the Board  shall
take  all  necessary actions to ensure that such  Options  remain
exercisable  for a period of at least twenty (20) days  prior  to
the   consummation.    Upon  consummation  of   the   Terminating
Transaction, all outstanding Options shall terminate and cease to
be  exercisable.  There shall be excluded from the  operation  of
the   provisions   of  this  Section  6.08(b)   any   Terminating
Transaction  in  which:   (i) the holders of  outstanding  Shares
prior to the Terminating Transaction retain or acquire securities
constituting a majority of the outstanding voting common stock of
the  acquiring  or  surviving corporation or  other  entity;  and
(ii)  no  single  person owns more than half of  the  outstanding
voting common stock of the acquiring or surviving corporation  or
other  entity.   For  purposes of this  Section  6.08(b),  voting
common  stock of the acquiring or surviving corporation or  other
entity, upon exercise of warrants or options, shall be considered
outstanding,  and  all securities that vote in  the  election  of
directors  (other than solely as the result of a default  in  the
making  of  any  dividend or other payment) shall  be  deemed  to
constitute that number of shares of voting common stock  that  is
equivalent  to the number of such votes that may be cast  by  the
holders of such securities.

            Notwithstanding the foregoing, in the event that  any
person  or  group  of  persons  commences  a  tender  offer   for
outstanding Shares within the scope of Regulation 14D  under  the
Exchange  Act,  all outstanding Options shall become  immediately
exercisable.  Any Shares received upon this accelerated  exercise
that  are not purchased pursuant to the offer (whether by failure
of  the offer or otherwise) shall be subject to repurchase at the
exercise  price by the Company upon termination of the Optionee's
service  as  a Director, in accordance with the vesting  schedule
that corresponds to the schedule of exercisability for the Option
under which the Shares were acquired.

            (c)  To  the maximum extent possible, any adjustments
authorized   under  this  Section  6.08  with  respect   to   any
outstanding  Options  shall  be  made  by  means  of  appropriate
adjustments to the number of Shares (or other securities) and the
option exercise price therefor under the unexercised portions  of
such  outstanding  Options, but without  changing  the  aggregate
exercise price applicable to said unexercised portions.   In  all
cases,  the  nature and extent of adjustments under this  Section
6.08 shall be determined by the Board in its sole discretion, and
any  such determination as to what adjustments shall be made, and
the  extent  thereof, shall be final and binding.  No  fractional
shares  of stock shall be issued under the Plan pursuant  to  any
such adjustment.

      6.09  Taxes.  The Board shall make such provisions and take
such  steps  as  it  deems  necessary  or  appropriate  for   the
withholding  of any federal, state, local and other tax  required
by law to be withheld with respect to the grant or exercise of an
Option,  or  with  respect to the disposition of Shares  acquired
pursuant  to  the  exercise of an Option pursuant  to  the  Plan,
including, but not limited to, the deduction of the amount of any
such  withholding  tax  from any compensation  or  other  amounts
payable  to  an  Optionee  by  any member  of  the  Participating
Companies,   or   requiring  an  Optionee  (or   the   Optionee's
beneficiary or legal representative), as a condition of  granting
or   exercising  an  Option,  to  pay  to  any  member   of   the
Participating Companies any amount required to be withheld, or to
execute  such  other  documents as the Board deems  necessary  or
desirable  in connection with the satisfaction of any  applicable
withholding obligation.  An Optionee may, in lieu of remitting to
the  Company amounts sufficient to satisfy federal, state,  local
or  other  withholding tax requirements, direct  the  Company  to
withhold Shares or deliver Shares in each case with a value equal
to such withholding tax requirements.

      6.10   Legends  on  Options and Stock  Certificates.   Each
Option   Agreement  and  each  certificate  representing   Shares
acquired  upon exercise of an Option shall be endorsed  with  all
legends,  if  any,  required  by  applicable  federal  and  state
securities  laws to be placed on the Option Agreement and/or  the
certificate.  The determination of which legends, if  any,  shall
be placed upon Option Agreements and/or said Shares shall be made
by  the Board in its sole discretion, and such decision shall  be
final and binding.


                          ARTICLE VII
                AMENDMENT OR TERMINATION OF PLAN

            The  Board may amend, alter and/or terminate the Plan
at any time; provided, however, that no change shall be effective
unless approved by the stockholders of the Company if such change
would  cause  the Plan to fail to comply with Rule 16b-3  of  the
Exchange Act or any successor rule under such Act as in effect on
the  date  of  such  amendment; provided,  further,  that  unless
required  by applicable law, rule or regulation, no amendment  of
the  Plan  shall affect in a material and adverse manner  Options
granted  prior  to  the  date of any such amendment  without  the
consent  of  any Optionee holding any such affected Options;  and
provided, further, that the provisions of Sections 6.01, 6.02 and
6.03  shall  not be amended more than once every six (6)  months,
other  than  to comport with changes in the I.R.C., the  Employee
Retirement Income Security Act or the rules thereunder.





                          ARTICLE VIII
                       GENERAL PROVISIONS

     8.01  Availability of the Plan.  A copy of the Plan shall be
delivered to the Secretary of the Company and shall be  shown  by
the  Secretary to any Eligible Director making reasonable inquiry
concerning the Plan.

     8.02  Notice.  Any notice or other communication required or
permitted  to be given pursuant to the Plan or under  any  Option
Agreement  must be in writing and may be given by  registered  or
certified  mail  and, if given by registered or  certified  mail,
shall  be  determined  to have been given  and  received  when  a
registered  or certified letter containing such notice,  properly
addressed with postage prepaid, is deposited in the United States
mails  and,  if given otherwise than by registered  or  certified
mail,  shall be deemed to have been given when delivered  to  and
received  by the party to whom addressed.  Notice shall be  given
to Eligible Directors at their most recent addresses shown in the
Company's  records.  Notice to the Company shall be addressed  to
the  Company at the address of the Company's principal  executive
offices, to the attention of the Secretary of the Company.

      8.03  Titles and Headings.  Titles and headings of sections
of  the Plan are for convenience of reference only and shall  not
affect the construction of any provision of the Plan.

      8.04   Governing  Law.   The Plan  shall  be  governed  by,
interpreted  under and construed and enforced in accordance  with
the  internal  laws, and not the laws pertaining to conflicts  or
choice  of  laws,  of  the  State  of  Delaware,  applicable   to
agreements  made and to be performed wholly within the  State  of
Delaware.