Exhibit 10.19
                              UNCONDITIONAL GUARANTY


     THIS  UNCONDITIONAL  GUARANTY (this "Guaranty") is made as of the _____ day
of January, 1999 by GSE SYSTEMS, INC., a Delaware corporation (the "Guarantor"),
in favor of FIRST UNION  NATIONAL BANK (the  "Lender,"  which term shall include
any subsequent holder of the Notes (as defined below)).

                                    Recitals

     A. $7,000,000 GSE Power Line of Credit

     A-1. The Lender extended a line of credit in the original  principal amount
of $7,000,000 (the "GSE Power Line of Credit") to GSE Power Systems, Inc. (f/k/a
Simulation,  Systems & Services  Technologies  Company),  a Delaware corporation
("GSE  Power") and MSHI,  INC., a Virginia  corporation  ("MSHI")  pursuant to a
Letter of Credit, Loan and Security Agreement dated January 30, 1996, as amended
from time to time (the "GSE Power Line of Credit Agreement"). The GSE Power Line
of Credit is  evidenced  by a  Promissory  Note dated  January  30,  1996 in the
original principal amount of $7,000,000,  as amended from time to time (the "GSE
Power Line of Credit Note").

     A-2.  Pursuant to the GSE Power Line of Credit  Agreement,  the Lender also
agreed to issue from time to time, subject to the provisions thereof, letters of
credit. In connection therewith, GSE Power and MSHI entered into separate Master
Letter of Credit  Agreements dated January 30, 1996, in favor of the Lender (the
"GSE Power Letter of Credit Agreements").

     A-3. The GSE Power Line of Credit  Agreement,  the GSE Power Line of Credit
Note,  the GSE  Power  Letter  of  Credit  Agreements  and all  other  documents
evidencing, securing, guaranteeing or otherwise related to the GSE Power Line of
Credit are collectively called the "GSE Power Loan Documents".

     A-4. As of December 18, 1998, exclusive of any amounts which may become due
in connection with the GSE Power Letter of Credit Agreements, there is due under
the GSE Power Line of Credit  principal of Five Million Eight  Hundred  Thousand
Nine Hundred and 00/100  Dollars  ($5,800,900.00)  and interest of  Twenty-Three
Thousand Six Hundred Fifty-Five and 00/100 Dollars ($23,655.00), plus attorneys'
fees and other costs which are payable under the GSE Power Loan Documents.

     A-5. Pursuant to Article III of the GSE Power Line of Credit Agreement, and
included  within the maximum  amount  available  to be borrowed by GSE Power and
MSHI under the GSE Power Line of Credit,  there is outstanding  Letter of Credit
No. SM406588 in the face amount of $180,243 issued by the Lender for the benefit
of Central  Trust of China  Procurement  Department  (the "GSE  Power  Letter of
Credit").

     B. $3,000,000 GSE Process Line of Credit

     B-1. The Lender extended a line of credit in the original  principal amount
of $7,000,000  (subsequently  reduced to  $3,000,000)  (the "GSE Process Line of
Credit") to GSE Process Solutions, Inc., a Delaware corporation ("GSE Process"),
pursuant to a Letter of Credit,  Loan and Security  Agreement  dated January 31,
1995, as amended and restated by an Amended and Restated Letter of Credit,  Loan
and Security Agreement dated October 13, 1995, as amended by an Amendment Number
One to Amended and Restated  Letter of Credit,  Loan and Security  Agreement and
Promissory  Note dated  February  23, 1996  ("Amendment  Number  One") and by an
Amendment Number Two to Amended and Restated Letter of Credit, Loan and Security
Agreement and Promissory Note dated November 11, 1997  ("Amendment  Number Two")
(collectively, the "GSE Process Line of Credit Agreement"). The GSE Process Line
of Credit is  evidenced  by a  Promissory  Note dated  October  13,  1995 in the
original  principal amount of $7,000,000 (which replaces a Promissory Note dated
January 31,  1995 in the original principal amount of $6,000,000), as amended by
Amendment Number One and by Amendment Number Two (collectively, the "GSE Process
Line of Credit Note")

     B-2. Pursuant to the GSE Process Line of Credit Agreement,  the Lender also
agreed to issue from time to time, subject to the provisions thereof, letters of
credit.  In connection  therewith,  GSE Process  entered into a Master Letter of
Credit  Agreement  dated  January  31,  1995,  in favor of the Lender  (the "GSE
Process Letter of Credit Agreement").

     B-3.  The GSE Process  Line of Credit  Agreement,  the GSE Process  Line of
Credit Note, the GSE Process Letter of Credit  Agreement and all other documents
evidencing,  securing, guaranteeing or otherwise related to the GSE Process Line
of Credit are collectively called the "GSE Process Loan Documents."

     B-4. As of December 18, 1998, exclusive of any amounts which may become due
in  connection  with the GSE Process  Letter of Credit  Agreement,  there is due
under the GSE Process Line of Credit principal of Zero and 00/100 Dollars ($-0-)
and  interest of One Thousand  One Hundred Ten and 52/100  Dollars  ($1,110.52),
plus  attorneys'  fees and other costs  which are payable  under the GSE Process
Loan Documents.

     B-5.  Pursuant to Article III of the GSE Process Line of Credit  Agreement,
and included  within the maximum amount  available to be borrowed by GSE Process
under the GSE Process Line of Credit,  there is outstanding Letter of Credit No.
405600 in the face  amount of  $630,000  issued by the Lender for the benefit of
8930 Stanford Boulevard, LLC (the "GSE Process Letter of Credit").

     C. GSE Power,  MSHI and GSE  Process  are called the  "Borrowers."  The GSE
Power Line of Credit and the GSE Process Line of Credit are called the "Lines of
Credit."  The GSE Power  Letter of Credit and the GSE  Process  Letter of Credit
(and  any  replacement  for  such  Letter  of  Credit  issued  pursuant  to  the
Modification  Agreement (as defined below)),  together with any other Letters of
Credit which may be issued by the Lender  pursuant to the terms of the Letter of
Credit  Agreements,  as amended by this Agreement,  are collectively  called the
"Letters of Credit." The GSE Power Line of Credit Note,  the GSE Process Line of
Credit  Note,  the GSE Power  Letter of Credit  Agreements  and the GSE  Process
Letter of Credit  Agreement  are  called  the "Notes."   The Notes and all other
documents evidencing,  securing,  guaranteeing or otherwise related to the Lines
of Credit or the Letters of Credit,  including any modifications,  restatements,
extensions, renewals and replacements thereof, are collectively called the "Loan
Documents," which term shall also include the Modification Agreement (as defined
below).

     D. GSE Power, MSHI, GSE Process, the Guarantor,  the Lender and others have
entered into a Modification  Agreement of even date herewith (the  "Modification
Agreement"), pursuant to which the Guarantor agreed to execute this Guaranty.

     NOW, THEREFORE, WITNESSETH, in consideration of the agreement of the Lender
to enter into the  Modification  Agreement,  the Guarantor  hereby covenants and
agrees as follows:

     The undersigned  hereby guarantees to the Lender that payment of principal,
interest,  late charges and any other sums payable under the Notes shall be made
according to the terms of the Notes without  deduction by reason of any set-off,
defense  or   counterclaim,   irrespective  of  any  invalidity   therein,   the
unenforceability thereof or the insufficiency, invalidity or unenforceability of
any  security  therefor,  and  hereby  unconditionally  consent  to  the  terms,
covenants and conditions of the Notes and the other Loan  Documents;  and hereby
consents,  without notice to the undersigned,  to the extension,  in whole or in
part from  time to time,  whether  or not for a term in  excess of the  original
term,  of the  payment of the Notes;  and agrees in case the dates of payment of
the Notes shall be extended in whole or in part,  that all moneys due thereunder
shall be paid when due according to such  extension or  extensions;  and further
consents  to the  waiving or  amendment  by the Lender of any term,  covenant or
condition  of the Notes or the other  Loan  Documents  or of any  indulgence  or
release granted  thereunder;  and further consents to any changes or alterations
which may be made in any term, covenant or condition of the Loan Documents;  and
agrees that no change, alteration, modification, renewal, or extension of any of
the Loan  Documents  shall  alter  or  affect  the  liability  of the  Guarantor
hereunder;  and further consents to the release of any collateral the Lender may
have  under  the  Loan  Documents  or to the  subordination  of the  Loan or the
collateral  securing the Loan to any other debt or security  interest under such
terms  and  conditions  as the  Lender  may  agree to in its  sole and  absolute
discretion;  and further hereby waives  presentment,  demand of payment from the
maker, protest and notice of nonpayment.

     If the  Borrowers  shall fail to make any  payment of any sum due under the
Notes, or if the Borrowers  shall default in any term,  covenant or condition of
the Loan Documents,  then the undersigned hereby  unconditionally  guarantees to
the Lender that the  undersigned  shall (without  first  requiring the Lender to
proceed against the Borrowers,  or any other security) (1) pay to the Lender the
entire unpaid  balance with interest and costs,  and (2) cure any default in any
term,  covenant or  condition of the Loan  Documents.  The  undersigned  further
agrees to  indemnify  and hold  harmless,  the Lender  from any loss  (including
actual  attorneys'  fees)  resulting  from any  default  made at any time by the
Borrowers  in any terms of the Loan  Documents or by the  undersigned  under the
terms of this Guaranty.

     The undersigned  hereby waives notice of acceptance of this Guaranty by the
Lender and any and all notices and demands of every kind and  description  which
may be required  to be given by any  statute or rule of law,  and agree that the
liability of the undersigned  hereunder shall in no way be affected,  diminished
or released by any forbearance  which may be granted to the Borrowers (or to any
successor  to it or to any  person  or  entity  which  shall  have  assumed  the
obligations  of the  Borrowers  under the  Notes) or by any  waiver of any term,
covenant or  condition  in the Loan  Documents by the Lender or by reason of any
change or  modification  in any of the Loan  Documents,  or by the acceptance of
additional  security  or the  release  by the Lender of any  security  or of any
person or entity primarily or secondarily liable.

     The  Guarantor  agrees  that this  Guaranty  may be  enforced by the Lender
without  the  necessity  at any time of  resorting  to or  exhausting  any other
security or collateral and without the necessity at any time of having  recourse
to the Notes or  enforcing  any rights it may have  against any other  person or
entity.  The  undersigned  further  agrees that nothing herein  contained  shall
prevent  the Lender from suing on the Notes or from  exercising  any other right
available  to it under the Notes or any of the other Loan  Documents  or against
any other person or entity, and the exercise of any of the aforementioned rights
shall not constitute a legal or equitable discharge of the undersigned, it being
the purpose and intent of the undersigned that his/her or its obligations  under
this  Guaranty   shall  be  absolute  and   unconditional   under  any  and  all
circumstances  and s/he or it shall be released  therefrom  only upon payment of
all sums due hereunder and under the Notes and the other Loan Documents.

     This Guaranty shall continue to be effective or be reinstated,  as the case
may be, if at any time any payment is rescinded or must otherwise be returned by
the Lender upon the insolvency, bankruptcy or reorganization of the Borrowers or
otherwise, all as though such payment had not been made.

     Any  indebtedness  of the  Borrowers  to the  Guarantor,  now or  hereafter
existing,  is hereby  subordinated  to the  indebtedness of the Borrowers to the
Lender.  The Guarantor agrees that, after a default (including the expiration of
any applicable cure period) in any term, covenant,  or condition of the Notes or
the other Loan  Documents  and until the  indebtedness  of the  Borrowers to the
Lender has been paid in full, the Guarantor will not seek, accept, or retain for
the Guarantor's  own account,  any payment from the Borrowers on account of such
subordinated  debt.  Following  a  default  (including  the  expiration  of  any
applicable cure period) in any term, covenant,  or condition of the Notes or the
other  Loan  Documents,  any  payments  to the  Guarantor  on  account  of  such
subordinated  debt shall be collected and received by the Guarantor in trust for
the Lender  and shall be paid over to the Lender on account of the  indebtedness
of the Borrowers to the Lender without impairing or releasing the obligations of
the Guarantor  hereunder.  Until ninety-five (95) days after the indebtedness of
the  Borrowers  to the  Lender  has been  paid in  full,  the  Guarantor  hereby
unconditionally  and  irrevocably  agrees that (1) the Guarantor will not at any
time assert  against the  Borrowers (or the  Borrowers'  estate in the event the
Borrowers  becomes  bankrupt or becomes  the  subject of any case or  proceeding
under the bankruptcy laws of the United States of America) any right or claim to
indemnification,  reimbursement, contribution, or payment for or with respect to
any and all amounts the  Guarantor  may pay or be  obligated  to pay the Lender,
including,  without limitation, the indebtedness of the Borrowers to the Lender,
and any and all  obligations  which  the  Guarantor  may  perform,  satisfy,  or
discharge,  under or with respect to this Guaranty and (2) the Guarantor  waives
and  releases  all such  rights  and claims to  indemnification,  reimbursement,
contribution, or payment which the Guarantor may have now or at any time against
the  Borrowers  (or the  Borrowers'  estate in the event the  Borrowers  becomes
bankrupt or becomes the subject of any case or proceeding  under the  bankruptcy
laws of the United States of America).

     The undersigned  hereby  authorizes any clerk of any court of record or any
attorney  to  enter in any  court  of  competent  jurisdiction  in the  State of
Maryland  or any other  State or  Territory  of the United  States  judgment  by
confession  against  the  undersigned  in favor  of the  Lender  for the  entire
principal  amount of the Notes then  remaining  unpaid  with  interest  thereon,
together with attorneys' fees of fifteen percent (15%) and court costs,  without
stay of  execution  or right of appeal  expressly  waiving  the  benefit  of all
exemption  laws and all  irregularity  or error in entering said judgment or the
execution thereon. No single exercise of the foregoing power to confess judgment
shall be deemed to exhaust the power,  whether or not any such exercise shall be
held by any court to be invalid,  voidable or void, but the power shall continue
undiminished,  and it may be exercised  from time to time as often as the Lender
shall elect,  until such time as the Lender shall have received  payment in full
of all  indebtedness  of the  Borrowers  to the Lender  together  with costs and
indebtedness  of  the  undersigned  under  this  Guaranty.  Notwithstanding  the
Lender's  right to  obtain  a  confessed  judgment  which  includes  an award of
attorneys'  fees of 15% of the unpaid  principal  sum, the Lender agrees that at
such time as all  indebtedness  under the Notes is fully paid,  the Lender shall
only be entitled to recover its actual  attorneys fees and expenses incurred in
connection with the Notes.

     The  undersigned  hereby  waives all right to trial by jury of all  claims,
defenses,  counterclaims  and suits of any kind arising from or relating to this
Guaranty.  The  undersigned  acknowledges  that  s/he or it  makes  this  waiver
voluntarily  and  knowingly  after  consultation  with counsel of his/her or its
choice. The undersigned agrees that all such claims, defenses, counterclaims and
suits shall be tried before a judge of competent jurisdiction, without a jury.

     All  laws  exempting  real  or  personal   property  from  execution,   and
inquisition and extension upon any levy on real or personal  property are hereby
waived and  condemnation  agreed to, and no benefit of exemption will be claimed
under or by virtue of any exemption  law now in force or which  hereafter may be
passed.

     The undersigned hereby waives promptness,  diligence,  notice of acceptance
and any other notice with respect to any of the terms,  covenants or  conditions
of this Guaranty or any of the other Loan Documents and any requirement that the
Lender protect,  secure,  perfect or insure any security interest or lien or any
property  subject  thereto or exhaust  any right or take any action  against the
Borrowers or any other person or entity or any collateral.

     Notwithstanding  anything  to the  contrary  herein,  the Lender  agrees to
notify the undersigned upon the occurrence of an Event of Default (as defined in
the Modification Agreement).

     The undersigned hereby requests the Lender, if it wishes to send any notice
to the undersigned,  although all notices and demands have been waived except as
set forth in the  immediately  preceding  paragraph,  to send such notice to the
undersigned  at 9189 Red  Branch  Road,  Columbia,  Maryland  21045,  Attention:
Stephen J. Fogarty.

     The  undersigned  hereby  acknowledges,  consents  and  agrees (1) that the
provisions of this Guaranty and the rights of all parties mentioned herein shall
be governed by the laws of the State of Maryland and  interpreted  and construed
in accordance with such laws (excluding  Maryland conflict of laws) and (2) that
the United States  District  Court for the District of Maryland and any court of
competent  jurisdiction of the State of Maryland shall have  jurisdiction in any
proceeding instituted to enforce this Guaranty,  and any objections to venue are
hereby waived.

     A default  (including the expiration of any applicable  cure period) in any
term,  covenant,  or  condition of the Notes or the other Loan  Documents  shall
constitute and be deemed a default under this Guaranty.

     Upon a  default  under  this  Guaranty,  including  the  expiration  of any
applicable  grace or cure  periods,  the Lender  may,  at its option and without
notice or demand,  declare an amount equal to the  remainder  of the  Borrowers'
obligations  under the Loan Documents to be  immediately  due and payable by the
Guarantor,  whether or not the same are due and payable by the Borrowers at that
time.  The books  and  records  of the  Lender  showing  the  amount  due by the
Borrowers  shall be binding upon the Guarantor  for the purpose of  establishing
such items and shall be prima facie proof thereof.  The Guarantor  agrees to pay
the Lender's  actual  attorneys' fees and all other costs and expenses which may
be incurred by the Lender in the  enforcement of this  Guaranty,  whether or not
suit is filed.

     The rights, powers,  privileges and discretions (the "rights") to which the
Lender may be entitled  hereunder  shall inure to the benefit of its  successors
and assigns. All the rights of the Lender are cumulative and not alternative and
may be enforced successively or concurrently.  Failure of the Lender to exercise
any of its rights  shall not be deemed a waiver  thereof and no waiver of any of
its  rights  shall be  deemed  to  apply to any  other  rights  nor  shall it be
effective unless in writing and signed by the Lender.  The terms,  covenants and
conditions  of or imposed  upon the  undersigned  herein  shall be binding  upon
his/her or its personal representatives, successors and assigns.

     In case any  provision  (or any part of any  provision)  contained  in this
Guaranty shall for any reason be held to be invalid, illegal or unenforceable in
any respect,  such invalidity,  illegality or unenforceability  shall not affect
any other  provision  (or  remaining  part of the  affected  provision)  of this
Guaranty but this  Guaranty  shall be construed as if such  invalid,  illegal or
unenforceable  provision (or part thereof) had never been  contained  herein but
only to the extent it is invalid, illegal or unenforceable.

     This Guaranty  replaces and  supercedes  all prior  guaranties  made by the
undersigned.

     Time is of the essence.

     IN WITNESS  WHEREOF,  the undersigned has executed this Guaranty under seal
effective as of the date first above written.

WITNESS/ATTEST:                             GSE SYSTEMS, INC.


                                            By:/S/   STEPHEN J. FOGARTY   (SEAL)
- -----------------------------------            --------------------------------

                                               Name: Stephen J. Fogarty
                                                    ---------------------------
                                            
                                              Title: Senior Vice President
                                                    ---------------------------
                                                              


STATE OF ______________________                     
                                            SS:
CITY/COUNTY OF _______________             

     I HEREBY CERTIFY that on this __________ day of ___________, 19____, before
me, the  undersigned  officer,  personally  appeared  ____________________,  who
acknowledged  himself/herself  to be the  ____________________  of GSE  Systems,
Inc., and that (s)he, in such capacity,  being authorized to do so, executed the
foregoing instrument for the purposes therein contained,  by signing the name of
GSE Systems, Inc., as ____________________ of GSE Systems, Inc.

     IN WITNESS WHEREOF, I hereunto set my hand and Notarial Seal.

                                            
                                               --------------------------------
                                              Notary Public
My Commission expires: