PRINCIPAL STOCKHOLDER AGREEMENT
          THIS PRINCIPAL  STOCKHOLDER  AGREEMENT,  dated as of October 7th, 1997
(this  "Agreement")  among Loral Space & Communications  Ltd., a Bermuda company
("Acquiror"),  Loral Satellite  Corporation,  a Delaware  corporation,  a wholly
owned subsidiary of Acquiror  ("Sub"),  Orion Network Systems,  Inc., a Delaware
corporation  ("Company"),  and  each  other  person  and  entity  listed  on the
signature pages hereof (each, a "Stockholder").
          WHEREAS,  as of the date hereof,  each Stockholder  holds of record or
beneficially  owns the  number of shares of common  stock,  $.01 par value  (the
"Common  Stock") of the Company set forth  opposite such  Stockholder's  name on
Exhibit A;
          WHEREAS,  as of the date  hereof,  certain  Stockholders  also hold of
record or  beneficially  own the number of shares of the  Company's  Series A 8%
Cumulative Redeemable Convertible Preferred Stock ("Series A Shares"),  Series B
8% Cumulative Redeemable Convertible Preferred Stock ("Series B Shares"), and/or
Series C 6% Cumulative Redeemable Convertible Preferred Stock ("Series C Shares,
and  together  with the  Series A Shares  and  Series B Shares,  the  "Preferred
Stock"),  set forth  opposite  such  Stockholder's  name on  Exhibit A (all such
Preferred Stock, together with all shares of Common Stock currently held and all
shares  of  Common  Stock  and  Preferred  Stock   hereafter   acquired  by  the
Stockholders  (including but not limited to shares acquired upon the exercise of
options,  warrants or rights or the  conversion  or exchange of  convertible  or
exchangeable securities) being referred to herein as the "Shares");
          WHEREAS,  as of the date hereof,  certain  Stockholders  also hold the
Company's  Convertible Junior Subordinated  Debentures due February 1, 2012 (the
"Debentures") in the principal amount set forth opposite such Stockholder's name
on Exhibit A;
          WHEREAS,  Acquiror, Sub and the Company have entered into an Agreement
and  Plan of  Merger  dated  as of the  date  hereof  (the  "Merger  Agreement";
capitalized  terms used but not  otherwise  defined in this  Agreement  have the
meanings assigned to such terms in the Merger Agreement),  which provides,  upon
the terms and subject to the conditions set forth therein, for the merger of Sub
with and into the Company (the "Merger");
                                       1
          WHEREAS,  as a condition  to the  willingness  of Acquiror  and Sub to
enter into the Merger  Agreement and in  furtherance  of the  acquisition of the
Company by Acquiror, Acquiror and Sub have required that the Stockholders agree,
and in order to induce Acquiror and Sub to enter into the Merger Agreement, each
Stockholder has agreed, severally and not jointly, to enter into this Agreement.
          NOW,  THEREFORE,  in  consideration  of  the  foregoing  premises  and
agreements contained herein, the parties hereto agree as follows:
                                   Article ▇.
                   ▇▇▇▇▇ OF OPTION AND EXERCISE; TRANSFER AND
                          VOTING OF SHARES; DEBENTURES
          Section 1.1. Grant of Option.
          Subject to the terms and conditions set forth herein, each Stockholder
hereby  severally and not jointly grants to Acquiror an irrevocable  option (the
"Option") to purchase all (but not less than all) of such  Stockholder's  Shares
held on the date of option  exercise (and to require the  conversion of all (but
not less than all) of such  Stockholder's  Debentures  into  Shares  immediately
prior to the Closing  (defined in Section  1.3 below)  hereunder,  and upon such
conversion such Shares shall be subject to the Option  hereunder) for the number
of fully paid and nonassessable Acquiror Shares (as adjusted pursuant to Section
2.5 of the Merger  Agreement)  equal to the number of Shares to be  purchased by
Acquiror  multiplied by the Exchange Ratio  (calculated using the Notice Date as
if it were the "Closing Date" (as defined in the Merger  Agreement) for purposes
of calculating the  Determination  Price),  together with the associated  rights
under Acquiror's Rights Agreement ("Acquiror Rights Plan") dated as of March 27,
1996 between Acquiror and The Bank of New York, as Rights Agent  (together,  the
"Purchase Price").
          Section 1.2. Exercise of Option.
          (a) Provided that neither Acquiror nor Sub shall be in material breach
of their respective  agreements or covenants  contained in the Merger Agreement,
Acquiror may exercise the Option, in whole (but not in part) with respect to all
of the Shares of all of the Stockholders covered hereby (but not less than all),
at any time  following the  occurrence of any event  described in Section 1.9 (a
"Purchase Event"); provided that, the Option shall terminate
                                       2
and be of no further  force and  effect  upon the  earliest  to occur of (i) the
Effective Time, (ii) June 30, 1998, or (iii) termination of the Merger Agreement
by Acquiror or Sub in accordance with the terms thereof.
          (b) If  Acquiror  exercises  the Option  hereunder  (except  following
termination of the Merger Agreement by the Company) (i) neither Acquiror nor Sub
shall  terminate the Merger  Agreement  under any  circumstances  except Section
9.1(a)  (with  approval  of the  Company)  and  Section  9.1(c)  of  the  Merger
Agreement,  (ii) all  conditions set forth in Section 8.2 and Section 8.3 (other
than Section  8.2(c) and Section  8.3(c),  but it is understood  and agreed that
receipt of an initial  FCC order shall be deemed to satisfy  Section  8.2(c) and
Section 8.3(c) for this purpose) of the Merger  Agreement shall be deemed waived
by each of Acquiror, Sub, and the Company, respectively,  (iii) Acquiror and Sub
shall each use their  reasonable  best efforts to consummate  the Merger (or the
Exchange Offer as applicable) as promptly as  practicable,  except to the extent
that (and so long as)  consummation  of the  Merger  (or the  Exchange  Offer as
applicable)  would violate  applicable  law (and if  consummation  of the Merger
would  violate  applicable  law, but  conducting  the  Exchange  Offer would not
violate  applicable  law,  Acquiror shall conduct the Exchange Offer pursuant to
the  requirements  of  Section  7.15  (including  Section  7.15(g)),  except  as
otherwise provided in this paragraph rather than the Merger).
          (c) If following  the  exercise of the Option there is an  Acquisition
Proposal  pending prior to consummation of the Merger or the Exchange Offer, and
such Acquisition  Proposal  includes a per Share price higher than the per Share
consideration  to be paid in the Merger or the Exchange  Offer as  applicable (a
"Topping  Bid"),  Acquiror  shall have the right to tender the Shares  purchased
under the Option into the Topping Bid or  otherwise  support the Topping Bid and
realize value therefrom,  and Acquiror's  obligations under the Merger Agreement
(and  Section 1.6 hereof)  shall (if not  previously  terminated)  be  suspended
during the pendency of the Topping Bid; provided, however, that such obligations
shall cease to be  suspended  if the Topping Bid ceases to be pending  without a
majority of the Shares having been acquired pursuant to the Topping Bid.
          Section 1.3. Closing Date.
          In the event Acquiror wishes to exercise the Option, which may only be
exercised  in whole (but not in part),  with respect to all of the Shares of all
of the
                                      3
Stockholders  covered hereby it shall send to each  Stockholder a written notice
(the date of which being herein  referred to as the "Notice Date")  specifying a
place and date not earlier  than five  business  days nor later than 20 Business
Days from the Notice Date for the closing of such purchase (the "Closing Date");
provided  that if the closing of the  purchase  and sale  pursuant to the Option
(the  "Closing")  cannot be consummated  by reason of any  applicable  judgment,
decree, order, law or regulation, Acquiror shall use its commercially reasonable
efforts to resolve  such matters and close as promptly as  practicable.  Without
limiting the foregoing,  if prior  notification to or approval of any regulatory
authority  is  required  in  connection  with such  purchase,  Acquiror  and, if
applicable, a Stockholder shall promptly file the required notice or application
for  approval  and shall  expeditiously  process the same (and such  Stockholder
shall  cooperate  with Acquiror in the filing of any such notice or  application
and the obtaining of any such approval).
          Section 1.4. Payment and Delivery of Certificates.
          (a) Subject to the terms and conditions of this Agreement, in reliance
on the representations,  warranties and covenants of each Stockholder  contained
herein  and in full  payment  for the  Shares,  at the  Closing,  Acquiror  will
deliver,   or  cause  to  be  delivered,   to  each  Stockholder,   certificates
representing  the Acquiror Shares to be paid pursuant to Section 1.1 duly issued
to each Stockholder,  together with any necessary stock transfer stamps properly
affixed.  Subject to the terms and conditions in this Agreement,  in reliance on
the  representations,  warranties and covenants of the Acquiror contained herein
and in the Merger Agreement,  at the Closing,  the Stockholders shall deliver to
Acquiror  certificates  representing  the  Shares  sold by the  Stockholders  to
Acquiror at the Closing,  duly endorsed in blank or  accompanied by stock powers
duly executed by the Stockholders in blank, in proper form for transfer.
          (b) No  certificates  or scrip  representing  less  than one  share of
Acquiror Shares shall be issued upon the exercise of the Option.  In lieu of any
such fractional  share,  each Stockholder who would otherwise have been entitled
to a fraction of a share of Acquiror Shares upon exercise of the Option shall be
paid  at the  Closing  cash  (without  interest)  in an  amount  equal  to  such
Stockholder's  fractional part of a share of Acquiror  Shares  multiplied by the
last  reported  sale price of Acquiror  Shares,  as reported on the NYSE, on the
Closing Date.
                                       4
          Section 1.5. Legends.
     (a) Each  Stockholder  shall instruct the Company to cause each certificate
of any Stockholder evidencing the Shares to bear a legend in the following form:
     THE SHARES  REPRESENTED BY THIS  CERTIFICATE MAY NOT BE SOLD,  EXCHANGED OR
     OTHERWISE  TRANSFERRED  OR DISPOSED OF EXCEPT IN COMPLIANCE  WITH THE TERMS
     AND CONDITIONS OF THE PRINCIPAL  STOCKHOLDER  AGREEMENT DATED AS OF OCTOBER
     7, 1997 AS IT MAY BE  AMENDED,  AMONG LORAL  SPACE &  COMMUNICATIONS  LTD.,
     LORAL SATELLITE CORPORATION, ORION NETWORK SYSTEMS, INC. ("ISSUER") AND THE
     REGISTERED  HOLDER OF THIS  CERTIFICATE,  A COPY OF WHICH IS ON FILE AT THE
     PRINCIPAL EXECUTIVE OFFICES OF THE ISSUER.
     (b) In  the  event  that  the  Shares  shall  cease  to be  subject  to the
restrictions  on transfer set forth in this Agreement,  the Company shall,  upon
the  written  request  of  the  holder  thereof,  issue  to  such  holder  a new
certificate  evidencing  such  Shares  without  the legend  required  by Section
1.5(a).
     Section 1.6. Voting Agreement; Agreement to Tender.
                  (a) Each  Stockholder  and Acquiror  hereby  severally and not
jointly  agrees  that  from  the  date  hereof  to the  earlier  to occur of the
termination of the Merger Agreement or the Effective Time, at any meeting of the
stockholders of the Company, however called, and in any action by consent of the
stockholders  of the  company,  such  Stockholder  and  Acquiror  shall vote the
Shares:  (i) in favor of the Merger,  the Merger Agreement (as amended from time
to  time)  and  the   transactions   contemplated   by  the   Merger   Agreement
(collectively,  the "subject  transactions"),  (ii) against any proposal for any
recapitalization,  merger  (other  than the  Merger),  sale of  assets  or other
business  combination  between the Company and any person or entity  (other than
Acquiror or Sub) or any other action or agreement  that would result in a breach
of any covenant or any other  obligation  or agreement of the Company  under the
Merger  Agreement or which would result in any of the  conditions  to the Merger
Agreement not being  fulfilled and (iii)  against the following  actions  (other
than pursuant to the terms of this Agreement or the Merger  Agreement):  (A) any
extraordinary  corporate transaction,  such as a merger,  consolidation or other
business  combination  involving the Company or any of it Subsidiaries;  (B) any
sale, lease or transfer by the Company of a material amount of assets (including
stock)  of  the  Company  or  any  of  its  Subsidiaries;  or a  reorganization,
restructuring, recapitalization, special dividend, dissolution or liquidation of
the  Company or any of its  Subsidiaries;  or (C)(1)
                                       5
any change in a majority of the persons who constitute the board of directors of
the  Company  or  any  of its  Subsidiaries;  (2)  any  change  in  the  present
capitalization of the Company or any of its Subsidiaries  including any proposal
to sell a substantial equity interest in the Company or any of its Subsidiaries;
(3)  any  amendment  to the  Company  or any of its  Subsidiaries'  charters  or
By-laws;  (4)  any  other  change  in the  Company  or any of its  Subsidiaries'
corporate  structure or business;  or (5) any other action which, in the case of
each of the matters referred to in clauses (C)(1), (2), (3) or (4), is intended,
or could reasonably be expected, to impede,  interfere with, delay, postpone, or
materially adversely affect the Merger and the transactions contemplated by this
Agreement.
     (b) Each Stockholder and Acquiror  severally and not jointly agrees that it
shall not enter into any agreement or understanding the effect of which would be
inconsistent  with or  violative  of the  provisions  and  agreements  contained
herein,  including in this Section 1.6.  Further,  each Stockholder and Acquiror
severally and not jointly  agrees that it will, if the Board of Directors of the
Company fails or refuses (other than as a result of breach by Acquiror or any of
its  Affiliates  of the  Merger  Agreement  or  because  the  Acquiror  and  its
Affiliates  will not or cannot  satisfy  the  conditions  precedent  thereto) to
submit the subject transactions to the Company's  stockholders,  vote all Shares
held of record or  beneficially  owned by it to (i) call or cause to be called a
special meeting of stockholders of the Company (or effect a written  consent) to
remove  the  directors  of the  Company  who have so  failed or  refused,  or to
increase  the  size of the  Board  of  Directors  and  elect a  majority  of new
directors who will submit the subject  transactions  to the  stockholders of the
Company for a vote, and (ii) use its  reasonable  efforts to effect such removal
and  replacement,  or increase and election,  and the  submission of the subject
transactions  to the  stockholders  of the Company;  and (iii) at any time after
initial approval by the stockholders of the Company of the subject transactions,
if so  requested  by  Acquiror,  to approve all or any  actions  incident to the
subject  transactions  or the other  matters  referred to in this Section 1.6 by
stockholder written consent.
     (c) If there is an Exchange  Offer  pursuant to Section  7.15 of the Merger
Agreement,  each Stockholder agrees to tender such Stockholder's Shares into the
Exchange  Offer   (including  all  Shares   issusable  upon  conversion  of  the
Debentures; provided, however, that actual conversion need not be effected until
consummation of the Exchange Offer).
     Section 1.7. No Disposition or Encumbrance of Shares and Options.
                                       6
               Except to the extent  set forth in  Exhibit  B, each  Stockholder
          hereby  severally and not jointly  covenants and agrees that, from the
          date hereof to the  termination  of the rights of Acquiror  under this
          Agreement,  it shall  not,  and shall  not  offer or agree  to,  sell,
          transfer,  tender,  assign,  hypothecate  or otherwise  dispose of, or
          create or permit to exist any Encumbrance (as hereinafter  defined) on
          the  Shares  owned  by  such  Stockholder  at any  time  prior  to the
          Effective Time.
               Section 1.8. Voting of Shares; Further Assurances.
     (a) Each Stockholder,  by this Agreement,  with respect to its Shares, does
hereby  constitute  and  appoint  Sub and  Acquiror,  or any  nominee of Sub and
Acquiror,  with full power of substitution,  from the date hereof to the earlier
to occur of the  termination of the Merger  Agreement or the Effective  Time, as
its true and lawful attorney and proxy (its "Proxy"), for and in its name, place
and stead, to vote each of such Shares as its Proxy, at every annual, special or
adjourned  meeting of the  stockholders  of the Company,  including the right to
sign its name (as  stockholder)  to any consent,  certificate  or other document
relating  to the  Company  that the law of the State of  Delaware  may permit or
require:
                    (i) in favor of the Merger, the Merger Agreement (as amended
          from time to time) and the  transactions  contemplated  by the  Merger
          Agreement;
                    (ii)    against   any    Acquisition    Proposal   for   any
          recapitalization,  merger  (other than the Merger),  sale of assets or
          other  business  combination  between  the  Company  and any person or
          entity  (other than  Acquiror or Sub) or any other action or agreement
          that would result in a breach of any covenant or any other  obligation
          or agreement of the Company under the Merger  Agreement or which could
          result in any of the  conditions  to the  Merger  Agreement  not being
          fulfilled; and
                    (iii) against (A) any extraordinary corporate transaction,
          such as a merger, consolidation or other business combination
          involving the Company or any of its Subsidiaries, (B) any sale, lease,
          or transfer by the Company of a material amount of assets (including
          stock) of the Company or any of its Subsidiaries, or a reorganization,
          restructuring, recapitalization, special dividend, dissolution or
          liquidation of the Company or any of its Subsidiaries; or (C) (1) any
          change in a majority of the persons who constitute the board of
          directors of the Company or any of its Subsidiaries; (2) any change in
          the present capitalization of the Company or any of its Subsidiaries
                                       7
including any proposal to sell a substantial  equity  interest in the Company or
any  of  its  Subsidiaries;   any  amendment  of  the  Company  or  any  of  its
Subsidiaries' charters or By-laws; (4) any other change in the Company or any of
its  Subsidiaries'  corporate  structure  or  business;  or (5) any other action
which, in the case of each of the matters  referred to in clauses  (C)(1),  (2),
(3) or (4), is intended, or could reasonably be expected,  to impede,  interfere
with,  delay,  postpone,  or  materially  adversely  affect  the  Merger and the
transactions contemplated by this Agreement.
                    THIS  POWER  OF  ATTORNEY  IS  IRREVOCABLE,  IS  GRANTED  IN
          CONSIDERATION  OF ACQUIROR AND SUB ENTERING INTO THE MERGER  AGREEMENT
          AND IS  COUPLED  WITH AN  INTEREST  SUFFICIENT  IN LAW TO  SUPPORT  AN
          IRREVOCABLE  POWER.  This appointment shall revoke all prior attorneys
          and proxies  appointed by any  Stockholder at any time with respect to
          the Shares and no subsequent attorneys or proxies will be appointed by
          such  Stockholder,  or be effective,  with respect  thereto during the
          term of this Agreement.
          (a) Each Stockholder  shall perform such further acts and execute such
further  documents and  instruments as may reasonably be required to vest in Sub
and  Acquiror the power to carry out and give effect to the  provisions  of this
Agreement.
          (b)  Nothing  contained  in this  Section  1.8 shall be  construed  to
invalidate any action taken by a Stockholder in accordance with Section 1.8.
               Section 1.9. Purchase Events.
               Acquiror  may  exercise  the  Option  only  if one or more of the
following events has occurred:
          (a) the Board of  Directors  of the Company or any  committee  thereof
shall have withdrawn or modified its approval or recommendation of the Merger or
the  Merger  Agreement  in any  manner  adverse  to  Acquiror,  or  approved  or
recommended any Acquisition  Proposal (as defined in the Merger  Agreement),  or
shall have adopted a resolution to take any of the foregoing actions;
          (b) (i) the approval of the Merger  Agreement by the  stockholders  of
the Company  shall have not been obtained by reason of the failure to obtain the
required vote at the Stockholders'  Meeting (as defined in the Merger Agreement)
and (ii) at the time of such negative vote there shall be pending an Acquisition
Proposal (as defined in the Merger Agreement);
          (c) the Company or any of its Subsidiaries shall have
                                       8
entered into any  agreement  with any person  (other than Acquiror or any of its
affiliates),  the  Board  of  Directors  of such  entity  shall  have  approved,
recommended  or resolved  to enter into an  agreement  with any  person,  or the
Company shall have publicly announced its intention to take any of the foregoing
actions, with respect to the sale of 20% or more (in voting power) of the voting
securities of the Company or of 20% or more (in fair market value) of the assets
of the Company and its  Subsidiaries,  on a  consolidated  basis,  however  such
transaction may be effected; or
          (d) any person (other than Acquiror or any of its  affiliates),  shall
have  commenced  (as such term is  defined in Rule  14d-2  under the  Securities
Exchange Act of 1934,  as amended (the  "Exchange  Act"),  or shall have filed a
registration statement under the Securities Act of 1933, as amended (the "Act"),
with respect to a tender or exchange  offer for securities  representing  35% or
more of the voting power of the Company;  or the  acquisition,  by any person or
group (as defined in Section 13(d) of the Exchange Act),  other than Acquiror or
any of its affiliates,  of beneficial ownership of (as defined in the Rule 13d-3
under the  Exchange  Act),  or the right to  acquire  beneficial  ownership  of,
securities representing 35% or more of the voting power of the Company;
         provided that no event set forth in this Section 1.9 shall be deemed to
         occur solely by reason of any  agreement,  or any action that is taken,
         or of any event that  occurs,  for which  Acquiror  has given its prior
         written  consent.  As used in this  Agreement,  "person" shall have the
         meaning specified in Section 13(d)(3) of the Exchange Act.
          Section 1.10. Convertible Debentures.
          Each Stockholder that holds Debentures agrees that all Debentures held
by such  Stockholder  shall be converted  into shares of Common Stock  (together
with any shares of Common Stock representing  accrued but unpaid interest on the
Debentures) in accordance with Section 15.1 of the Debenture Purchase Agreement,
dated as of January  13,  1997,  as amended as of January  31,  1997,  among the
Company,  British  Aerospace  Holdings,  Inc. and Matra Marconi Space UK Limited
(the "Debenture  Agreement") relating thereto immediately prior to the Effective
Time (except if converted prior to such date), and at such time,  converted into
the right to receive in the Merger  Acquiror Shares in accordance with the terms
of the Merger Agreement.  In consideration  for the foregoing,  such Stockholder
waives its rights under Section 11.3 of the Debenture  Agreement with respect to
the consummation of the Merger.
                                       9
          Section 1.11. Control Shares
          The Company hereby waives its rights under Article  ELEVENTH,  Section
H, of its  Restated  Certificate  of  Incorporation  with  respect to all Shares
acquired  pursuant  to  exercise  of the  Option,  and hereby  agrees,  promptly
following any such exercise, to exchange for such Shares an equal number of duly
authorized,  but unissued  Shares,  which upon issuance will be validly  issued,
fully paid and  nonassessable  Shares,  and which will not be  "control  shares"
within the meaning of such Article ELEVENTH.
                                   Article II.
               REPRESENTATIONS AND WARRANTIES OF THE STOCKHOLDERS
          Each  Stockholder,  severally and not jointly,  hereby  represents and
warrants to Acquiror as follows:
          Section 2.1. Due Organization, Authorization, etc.
          Such  Stockholder (if it is a corporation,  partnership or other legal
entity) is duly organized,  validly existing and in good standing under the laws
of the jurisdiction of its  incorporation or organization.  Such Stockholder has
all  requisite  power  (corporate  or  otherwise)  to execute and  deliver  this
Agreement,  to grant the Option and to consummate the  transaction  contemplated
hereby.  The  execution  and  delivery of this  Agreement,  the  appointment  of
Acquiror and Sub as such Stockholder's Proxy, the granting of the Option and the
consummation of the transactions  contemplated  hereby have been duly authorized
by  all  necessary  action   (corporate  or  otherwise)  on  the  part  of  such
Stockholder. This Agreement has been duly executed and delivered by or on behalf
of such Stockholder and, assuming its due authorization,  execution and delivery
by  Acquiror,  constitutes  a  legal,  valid  and  binding  obligation  of  such
Stockholder, enforceable against such Stockholder in accordance with its terms.
          Section 2.2. No Conflicts, Required filings and Consents.
          (a) The execution and delivery of this  Agreement by such  Stockholder
does not, and the  performance of this Agreement by such  Stockholder  will not,
(i) conflict  with or violate the  Certificate  of  Incorporation  by By-Laws or
other similar  organizational  documents of such  Stockholder  (in the case of a
Stockholder that is a corporation, partnership or other legal
                                       10
entity),  (ii)  conflict  with or violate any  statute,  law,  ordinance,  rule,
regulation, order, decree or judgment applicable to such Stockholder or by which
it or any of its properties is bound or affected,  or (iii) result in any breach
of or  constitute a default  (with or without  notice or lapse of time, or both)
under, or give to others any rights of termination,  amendment,  acceleration or
cancellation  of, or result in the creation of a lien or  encumbrance  on any of
the  property  or  assets  of such  Stockholder  or (if  such  Stockholder  is a
corporation,  partnership  or  other  legal  entity)  any of  its  subsidiaries,
including,  without limitation,  the Shares, pursuant to, any indenture or other
loan document provision or other contract,  license,  franchise, permit or other
instrument or obligation to which such  Stockholder  is a party or by which such
Stockholder or any of its properties is bound or affected,  except,  in the case
of clauses (ii) and (iii), for any such breaches,  defaults or other occurrences
that would not prevent the  performance by such  Stockholder of its  obligations
under this Agreement.
          (b) The execution and delivery of this  Agreement by such  Stockholder
do not, and the  performance  of this  agreement by such  Stockholder  will not,
require any  consent,  approval,  authorization  or permit of, or filing with or
notification to, any governmental or regulatory authority,  domestic or foreign,
except where the failure to obtain such consents,  approvals,  authorizations or
permits,  or to make  such  filings  or  notifications,  would not  prevent  the
performance by the Stockholder of its obligations under this Agreement.
          Section 2.3. Title to Shares.
          Such  Stockholder  has,  and the  transfer by the  Stockholder  of the
Shares  hereunder will pass,  good and marketable  title to the Shares listed on
Exhibit  A  hereto,  free and  clear of any  pledge,  lien,  security  interest,
mortgage,  charge, claim, equity,  option,  proxy, voting restriction,  right of
first refusal,  limitation on disposition,  adverse claim of ownership or use or
encumbrance  of any kind  ("Encumbrances"),  except to the extent  disclosed  on
Exhibit B and for Shares sold prior to the Closing as  permitted  under  Section
1.8.
          Section 2.4. No Brokers.
          Except as contemplated in the Merger Agreement,  no broker,  finder or
investment  banker  is  entitled  to any  brokerage,  finder's  or other  fee or
commission in connection with the transactions contemplated by this Agreement.
          Section 2.5. Investment Intent, Etc.
                                       11
          Each Stockholder is acquiring the Acquiror  Shares,  together with the
associated  rights,  to be received in the Merger or pursuant to the exercise of
the Option,  for its own account for  investment and not with a view towards the
resale,  transfer or  distribution  thereof,  nor with any present  intention of
distributing the Acquiror Shares.  Each Stockholder is an "accredited  investor"
within the meaning of Regulation D promulgated  under the Act. Each  Stockholder
has such knowledge and  experience in financial and business  matters that it is
capable of  evaluating  the merits and risks of an investment in Acquiror and is
able to bear the economic risk of such  investment  for an indefinite  period of
time.
                                  Article III.
                   REPRESENTATIONS AND WARRANTIES OF ACQUIROR
          Section 3.1. Authority Relative to the Agreement.
     (a) Acquiror has the corporate  power to execute and deliver this Agreement
and to carry out its obligations  hereunder.  The execution and delivery of this
Agreement and the consummation of the transactions contemplated hereby have been
duly authorized by Acquiror's  Board of Directors.  The Agreement  constitutes a
valid and  binding  obligation  of  Acquiror,  enforceable  against  Acquiror in
accordance  with its terms,  except as enforcement may be limited by bankruptcy,
insolvency or other similar laws affecting the enforcement of creditors'  rights
generally  and except that the  availability  of equitable  remedies,  including
specific performance, is subject to the discretion of the court before which any
proceeding therefor may be brought.  No other corporate  proceedings on the part
of Acquiror are necessary to authorize the execution and delivery by Acquiror of
this Agreement or the consummation of the transactions contemplated hereby.
     (b) The execution and delivery of this  Agreement and the  consummation  of
the transactions contemplated hereby, does not and will not result in the change
in  conversion  ratios,  conversion  rights or  voting  rights,  or the  breach,
violation,  default  (with  or  without  notice  or lapse  of  time,  or  both),
termination,  cancellation or  acceleration of any obligation,  or the loss of a
material benefit, under (i) the Acquiror's Memorandum of Association or bye-laws
or (ii) any  indenture  or other  loan  document  provision  or other  contract,
license,  franchise,  permit,  order,  decree,  concession,  lease,  instrument,
judgment,  statute, law, ordinance, rule or regulation applicable to Acquiror or
any of its Subsidiaries or their respective properties or assets, other than, in
the case of clause (ii)
                                       12
only,  (A) any  breaches,  violations,  defaults,  terminations,  cancellations,
accelerations or losses which, either singly or in the aggregate,  will not have
a  Acquiror   Material  Adverse  Effect  or  prevent  the  consummation  of  the
transactions contemplated hereby.
          Section 3.2. Representations in Merger Agreement.
          Acquiror   represents  and  warrants  to  each  Stockholder  that  the
     representations  and  warranties  set  forth  in  Article  V of the  Merger
     Agreement were (or will be) true and correct when made and on and as of the
     date  of  any  action  taken  by  Acquiror  hereunder   (including  without
     limitation  exercise  of the  Option)  with the same  effect as though such
     representations and warranties had been made on and as of such date (except
     for  representations  and  warranties  that speak as of a specific  date or
     time, which need only be true and correct as of such date or time),  except
     where the failure of such  representations and warranties to be so true and
     correct  (without  giving effect to any limitation as to  "materiality"  or
     "Acquiror  Material  Adverse  Effect" set forth  therein)  does not have an
     Acquiror Material Adverse Effect, and such  representations  and warranties
     shall be deemed incorporated herein;  provided,  however, that incorporated
     representations  and warranties  which relate to the Merger Agreement shall
     be deemed for purposes of this Section to have been modified to relate only
     to this Agreement.
                                   Article IV.
                         DISTRIBUTIONS; ADJUSTMENT UPON
                           CHANGES IN CAPITALIZATION.
          (a) Any  dividends or other  distributions  (whether  payable in cash,
stock  or  otherwise)  by the  Company  with  respect  to any  Shares  purchased
hereunder  with a record  date on or after  the  Closing  Date  will  belong  to
Acquiror. If any such dividend or distribution  belonging to Acquiror is paid by
the Company to the  Stockholder,  the  Stockholder  shall hold such  dividend or
distribution  in trust for the benefit of Acquiror and shall promptly remit such
dividend or distribution  to Acquiror in exactly the form received,  accompanied
by  appropriate  instruments  of  transfer.  If on or  after  the  date  of this
Agreement there shall occur any stock dividend,  stock split,  recapitalization,
combination  or exchange of shares,  merger,  consolidation,  reorganization  or
other change or transaction of or by the Company, as a result of which shares of
any class of stock, other securities,  cash or other property shall be issued in
respect of any Shares or if any Shares shall be changed into the same or
                                       13
another class of stock or other  securities,  then, upon exercise of the Option,
Acquiror  shall  receive for the  aggregate  price  payable upon exercise of the
Option with respect to the Shares,  all such shares of stock,  other securities,
cash or other property issued, delivered or received with respect to such Shares
(or if the Option shall not be exercised,  appropriate  adjustment shall be made
for purposes of the calculations set forth in this Agreement).
          (b) Any  dividends or other  distributions  (whether  payable in cash,
stock or  otherwise)  by Acquiror  with  respect to any Acquiror  Shares  issued
hereunder  with a record  date on or after the  Closing  Date will belong to the
Stockholder to which such Acquiror  Shares were issued.  If on or after the date
of  this  Agreement  there  shall  occur  any  stock   dividend,   stock  split,
recapitalization,  combination  or  exchange of shares,  merger,  consolidation,
reorganization or other change or transaction of or by Acquiror,  as a result of
which shares of any class of stock,  other  securities,  cash or other  property
shall be issued in  respect of any  Acquiror  Shares or if any  Acquiror  Shares
shall be changed  into the same or another  class of stock or other  securities,
then,  upon  exercise  of the Option,  each  Stockholder  shall  receive for the
aggregate  price payable to such  Stockholder  upon exercise of the Option,  all
such shares of stock, other securities, cash or other property issued, delivered
or  received  with  respect  to the  Acquiror  Shares  to be  delivered  to such
Stockholder  (or if the Option shall not be  exercised,  appropriate  adjustment
shall be made for purposes of the calculations set forth in this Agreement).
                                   Article V.
                        NO SOLICITATION OF TRANSACTIONS.
                           Each Stockholder  severally and not jointly covenants
         and agrees  that in its  capacity  as a  stockholder  of the Company it
         shall not,  through any officer,  director,  employee,  representative,
         agent or direct or indirect  stockholder  of the Company or any Company
         Subsidiary, directly or indirectly, take any action to (i) encourage,
         initiate or solicit the  submission  of any  proposal
         that constitutes an Acquisition Proposal, (ii) enter into any agreement
         with respect to or accept any Acquisition  Proposal or (iii) facilitate
         any  inquiries or the making of any proposal that  constitutes,  or may
         reasonably  be  expected  to lead  to,  an  Acquisition  Proposal.  The
         Stockholder  shall promptly  notify  Acquiror in writing of any request
         for information or Acquisition Proposal,  specifying reasonable details
         of any  inquiry  or  Acquisition  Proposal,  and  shall  keep  Acquiror
         informed as to the status of any such
                                       14
          discussions  or  negotiations.  Each  Stockholder  severally  and  not
          jointly  further  agrees to use its best efforts as a  stockholder  to
          cause the Company not to, directly or indirectly,  solicit,  initiate,
          seek,  or encourage  (including by way of  furnishing  information  or
          assistance),  or take other action to facilitate, any inquiries or the
          making of any proposal which constitutes or may reasonably be expected
          to lead to, an Acquisition Proposal.
                                   Article VI.
                         COVENANTS OF THE STOCKHOLDERS.
          Section 6.1. Negative Covenants.
          Each Stockholder agrees, until the Option has terminated, not to:
          (a) sell, transfer,  pledge,  assign or otherwise dispose of, or enter
into any  contract,  option  or other  arrangement  with  respect  to the  sale,
transfer,  pledge,  assignment or other disposition of, the Shares owned by such
Stockholder to any person other than Acquiror or Acquiror's  designee and except
as contemplated in Exhibit B;
          (b) acquire any  additional  shares of Common Stock  without the prior
consent of  Acquiror  other than  pursuant  to rights  under the  Company  Stock
Purchase Plans,  options  outstanding on the date of this  Agreement,  or Shares
issued in payment of interest on the  Debentures  or  dividends  on the Series C
Shares;
          (c) deposit  any Shares into a voting  trust or grant a proxy or enter
into a voting  agreement with respect to any Shares,  except for this Agreement;
or
          (d) take any action that would make any  representation or warranty of
such  Stockholder  contained  herein  untrue or  incorrect  or would result in a
breach by such  Stockholder of its obligations  under this Agreement or a breach
by the Company of its obligations under the Merger Agreement.
                    Section 6.2. Reliance; Further Assurances.
                    Each Stockholder  understands and acknowledges that Acquiror
          and Sub are entering  into the Merger  Agreement in reliance upon each
          Stockholder's  execution and delivery of this  Agreement.  If Acquiror
          shall  exercise  the  Option  in  accordance  with  the  terms of this
          Agreement,  from time to time and without additional consideration the
          Stockholder will execute and deliver, or cause to be executed and
                                       15
          delivered,   such  additional  or  further   transfers,   assignments,
          endorsements,   consents  and  other   instruments   as  Acquiror  may
          reasonably  request for the purpose of  effectively  carrying  out the
          transactions contemplated by this Agreement, including the transfer of
          the Shares to  Acquiror  and the  release of any and all  Encumbrances
          with respect thereto.
                    Section  6.3.   Transfer  of  Acquiror   Shares  by  British
          Aerospace.
          British Aerospace Space Systems,  Inc. and British Aerospace Holdings,
Inc.  (collectively,  "BAe") and Acquiror  agree to consult and  cooperate  with
respect to the orderly  disposition  of  Acquiror  Shares  obtained by BAe.  BAe
agrees that for a period of twelve months from the date it acquires the Acquiror
Shares  it will not,  and will  cause  each of its  affiliates  not to,  sell or
otherwise  transfer any Acquiror Shares other than by means of a block trade (or
a series  of block  trades)  with an  entity  that  qualifies  as a block  trade
positioner  (as that  term is  defined  and/or  interpreted  under  the  federal
securities  laws and the rules and  regulations  promulgated  thereunder) who is
experienced in block trade  transactions.  BAe shall consult with Acquiror prior
to such sale and seek the consent of Acquiror to such sale,  which consent shall
not be  unreasonably  withheld,  conditioned  or  delayed.  In the event of such
withholding  of consent,  BAe shall have the right to revise the proposed  sale,
and Acquiror shall  reconsider the revised sale in accordance  with the standard
of this Section. No delay in any proposed sale shall be beyond the expiration of
the twelve-month period. As an alternative to conducting block trades, BAe shall
have the  right to sell all (but  not  less  than  all) of its  Acquiror  Shares
pursuant to an underwritten  sale with an underwriter  reasonably  acceptable to
Acquiror. In such event, Acquiror shall modify the registration  statement filed
pursuant to Section 6.5 (or file a separate  registration  statement meeting the
requirements  of  Section  6.5) to enable  BAe to effect  such  sale.  Except as
provided in the prior  sentence,  Acquiror  shall not be  obligated to conduct a
"road show" or otherwise support such sale.
          Section 6.4. Affiliate Agreement.
                    Each Stockholder  acknowledges  that such Stockholder may be
          deemed an affiliate (as defined in Rule 12b-2 of the rules promulgated
          under the Exchange  Act) of the Company,  Acquiror or Sub, and further
          acknowledges  and agrees to  transfer,  sell or  otherwise  dispose of
          Acquiror Shares (including  Acquiror Shares acquired upon the exercise
          of  options,  warrants  or rights or the  conversion  or  exchange  of
          convertible or exchangeable securities) only (a) if such
                                       16
          transfer,  sale or disposition is registered  under the Act, (b) is in
          compliance with the requirements of paragraphs (c) and (d) of Rule 145
          promulgated   under  the  Act  ("Rule  145")  (as   indicated  in  the
          restrictive legend that will appear on the stock certificate),  or (c)
          pursuant to another exemption from registration under the Act for such
          offer  and  sale.  Each  Stockholder  agrees  not to make  an  illegal
          "distribution"  (within  the  meaning  of the  Act  and  Rule  145) of
          Acquiror  Shares.  Acquiror  shall be  entitled  to place  restrictive
          legends upon  certificates for each  Stockholder's  Acquiror Shares to
          enforce  the  applicable  provisions  of law and  this  Agreement  and
          Acquiror  shall not be required to maintain the  effectiveness  of the
          Proxy Registration Statement (or Exchange Registration  Statement,  as
          the case may be) under the Act for the  purposes of resale of Acquiror
          Shares by each Stockholder.
                    Section 6.5. Registration Rights.
                    (a) In the event that  Acquiror  exercises  the  Option,  as
          promptly as  practicable  following  the closing date for the exchange
          offer  referred  to in  Section  1.2 above  (but not more than 60 days
          following  the  Closing  Date),   Acquiror  shall  (i)  file  a  shelf
          registration  statement  covering all Acquiror Shares for the purposes
          of resale of  Acquiror  Shares  by each  Stockholder  and (ii) use its
          reasonable best efforts to cause such shelf registration  statement to
          become and remain  effective  for the  resale of all  Acquiror  Shares
          issued pursuant to this Agreement;  provided,  however,  that Acquiror
          shall be required to include in such registration statement only those
          Acquiror  Shares as to which the  Stockholder  holding  such  Acquiror
          Shares agrees to sell such shares in compliance with the  requirements
          of paragraphs (c) and (d) of Rule 145 that would have been  applicable
          to such sale if such  Acquiror  Shares had been  registered  under the
          Proxy Registration Statement (or Exchange Registration  Statement,  as
          the case may be) rather than such shelf registration statement.
                    (b)  Registrations  effected  under  this  Section  shall be
          effected at Acquiror's expense, including the fees and expenses of one
          counsel to the holders of Acquiror Shares, but excluding  underwriting
          discounts and  commissions to brokers or dealers.  In connection  with
          each  registration  under this Section,  Acquiror shall  indemnify and
          hold each  holder of  Acquiror  Shares  whose  shares  are  registered
          pursuant  to  such  registration  statement  (a  "Holder  of  Acquiror
          Shares"),  its underwriters  and each of their  respective  affiliates
          harmless against any and all losses, claims, damages,  liabilities and
          expenses (including,
                                       17
          without limitation,  investigation expenses and fees and disbursements
          of counsel and accountants), joint or several, to which such Holder of
          Acquiror  Shares,  its  underwriters  and  each  of  their  respective
          affiliates may become subject,  under the Securities Act or otherwise,
          insofar as such losses, claims,  damages,  liabilities or expenses (or
          actions in respect  thereof)  arise out of or are based upon an untrue
          statement or alleged untrue  statement of a material fact contained in
          such registration statement (including any prospectus therein), of any
          amendment or supplement thereto, or arise out of or are based upon the
          omission or alleged omission to state therein a material fact required
          to be stated therein or necessary to make the  statements  therein not
          misleading,  other than such losses, claims,  damages,  liabilities or
          expenses (or actions in respect  thereof) which arise out of are based
          upon an untrue  statement  or alleged  untrue  statement of a material
          fact  contained  in  written  information  furnished  by a  Holder  of
          Acquiror  Shares to Acquiror  expressly  for use in such  registration
          statement;  provided,  however, that the foregoing indemnity shall not
          inure  to  the  benefit  of  any  Holder  of  Acquiror   Shares,   its
          underwriters or respective affiliates, if a copy of the prospectus was
          not  sent or  given  by or on  behalf  of such  person  to the  person
          purchasing the Shares,  if required by law so to have been  delivered,
          at or prior to the written  confirmation  of the sale of the Shares to
          such person,  and if the  prospectus  (as so amended or  supplemented)
          would have cured the defect giving rise to such loss, claim, damage or
          liability.
                    (c) In connection with any registration  statement  pursuant
          to this  Section,  each  Holder of Acquiror  Shares  agrees to furnish
          Acquiror with such information concerning itself and the proposed sale
          or  distribution  as shall  reasonably  be required in order to ensure
          compliance with the requirements of the Securities Act. Each Holder of
          Acquiror  Shares shall indemnify and hold Acquiror,  its  underwriters
          and each of their respective  affiliates  harmless against any and all
          losses, claims,  damages,  liabilities and expenses (including without
          limitation  investigation  expenses  and  fees  and  disbursements  of
          counsel and  accountants),  joint or several,  to which Acquiror,  its
          underwriters  and  each of  their  respective  affiliates  may  become
          subject under the Securities Act or otherwise, insofar as such losses,
          claims,  damages,  liabilities  or  expenses  (or  actions  in respect
          thereof) arise out of or are based upon an untrue statement or alleged
          untrue  statement of a material fact contained in written  information
          furnished by any Holder of Acquiror  Shares to Acquiror  expressly for
          use in such registration statement. In no
                                       18
          event  shall the  liability  of any Holder of  Acquiror  Shares or any
          affiliate  thereof  under this  Section be greater in amount  than the
          dollar  amount of the  proceeds  received  by such  Holder of Acquiror
          Shares  upon  the  sale of the  Acquiror  Shares  giving  rise to such
          indemnification obligation.
                    (d) Upon the issuance of Acquiror Shares hereunder, Acquiror
          will use its  reasonable  best efforts  promptly to list such Acquiror
          Shares with the New York Stock  Exchange or on such  national or other
          exchange on which Acquiror Shares are at the time principally listed.
                                  Article VII.
                                  MISCELLANEOUS
                    Section 7.1. Non-Survival of Representations, Warranties and
          Agreements.
                    All  representations,  warranties and agreements made by the
          parties to this  Agreement  shall  terminate at the Closing except for
          those which by their terms are to be performed after the Closing.
                    Section 7.2. Expenses.
                    All costs  and  expenses  incurred  in  connection  with the
          transactions contemplated by this Agreement shall be paid by the party
          incurring such costs and expenses.
                    Section 7.3. Notices.
                    All  notices or other  communications  under this  Agreement
          shall be in  writing  and shall be given by  delivery  in  person,  by
          facsimile,   cable,   telegram,   telex  or  other  standard  form  of
          telecommunications,  or  by  registered  or  certified  mail,  postage
          prepaid, return receipt requested, addressed as follows (or such other
          address  for a party  as  shall  be  specified  in a  notice  given in
          accordance  with  this  Section  7.3) and shall be deemed to have been
          given  one  business  day after  transmission  by  facsimile  of other
          standard form of  telecommunications or four days after deposit in the
          US mail:
                                       19
                  If to the Company:
                  Orion Network Systems, Inc.
                  ▇▇▇▇ ▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇▇
                  ▇▇▇▇▇ ▇▇▇
                  ▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇  ▇▇▇▇▇
                  Telecopier No.: (▇▇▇) ▇▇▇-▇▇▇▇
                  Attention: President
                  With a copy (which shall not constitute notice) to:
                  ▇▇▇▇▇ & ▇▇▇▇▇▇▇ L.L.P.
                  Columbia Square
                  ▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇.▇.
                  ▇▇▇▇▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇
                  Telecopier No.:  (▇▇▇) ▇▇▇-▇▇▇▇
                  Attention:  ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇▇, Esq.
          If to a  Stockholder,  at the  address  or  facsimile  number  of such
Stockholder set forth on Exhibit A, with a copy to:
                  ▇▇▇▇▇ & ▇▇▇▇▇▇▇ L.L.P.
                  Columbia Square
                  ▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇.▇.
                  ▇▇▇▇▇▇▇▇▇▇, ▇▇  ▇▇▇▇▇
                  Telecopier No.: (▇▇▇) ▇▇▇-▇▇▇▇
                  Attention: ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇▇, Esq.
                  If to Acquiror or Sub, at:
                  Loral Space & Communications Ltd.
                  ▇▇▇ ▇▇▇▇▇ ▇▇▇▇▇▇
                  ▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇  ▇▇▇▇▇
                  Telecopier No.: (▇▇▇) ▇▇▇-▇▇▇▇
                  Attention: ▇▇▇▇ ▇. ▇▇▇▇▇▇, Esq.
                  with a copy to:
                  ▇▇▇▇▇▇▇ ▇▇▇▇ & ▇▇▇▇▇▇▇▇▇
                  One Citicorp Center
                  ▇▇▇ ▇▇▇▇ ▇▇▇▇ ▇▇▇▇▇▇
                  ▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇  ▇▇▇▇▇
                  Telecopier No.: (▇▇▇) ▇▇▇-▇▇▇▇
                  Attention: ▇▇▇▇▇ ▇. ▇▇▇▇▇, Esq.
                                       20
                    Section 7.4. Severability.
                    Any term or provision of this Agreement  which is invalid or
          unenforceable in any jurisdiction  shall, as to that jurisdiction,  be
          ineffective  to the  extent  of such  invalidity  or  unenforceability
          without  rendering  invalid or  unenforceable  the remaining terms and
          revisions   of  this   Agreement   or   affecting   the   validity  or
          enforceability  of any of the terms or provisions of this Agreement in
          any other jurisdiction. If any provision of this Agreement is so broad
          as to be unenforceable,  the provision shall interpreted to be only so
          broad as is enforceable.
                    Section 7.5. Entire Agreement.
                    This Agreement and any documents delivered by the parties in
          connection  herewith constitute the entire agreement among the parties
          with  respect to the subject  matter  hereof and  supersede  all prior
          agreements and understandings  among the parties with respect thereto.
          No addition to or  modification  of any  provision  of this  Agreement
          shall be binding  upon any party  hereto  unless  made in writing  and
          signed by all parties hereto.
                    Section 7.6. Assignment, Binding Effect.
                    Neither this  Agreement nor any of the rights,  interests or
          obligations  hereunder  shall be assigned by any of the parties hereto
          (whether by operation of law or  otherwise)  without the prior written
          consent of the other  parties,  except that Acquiror or Sub may assign
          all or any of their rights and obligations  hereunder to any affiliate
          of Acquiror,  provided that no such assignment  shall relieve Acquiror
          or Sub of its obligations  hereunder if such assignee does not perform
          such obligations.  Subject to the preceding  sentence,  this Agreement
          shall be binding  upon and shall  inure to the  benefit of the parties
          hereto and their  respective  successors and assigns.  Notwithstanding
          anything contained in this Agreement to the contrary,  nothing in this
          Agreement,  expressed or implied,  is intended to confer on any person
          other  than the  parties  hereto or their  respective  successors  and
          assigns any rights,  remedies,  obligations or liabilities under or by
          reason of this Agreement.
                    Section 7.7. Specific Performance.
                    The parties hereto agree that irreparable damage would occur
          in the event  that any of the  provisions  of this  Agreement  was not
          performed  in  accordance  with its  specific  terms or was  otherwise
          breached. It is accordingly agreed
                                       21
          that the parties shall be entitled to an injunction or  injunctions to
          prevent  breaches of this  Agreement and to enforce  specifically  the
          terms and  provisions  hereof in any  Delaware  Court,  this  being in
          addition to any other  remedy to which they are  entitled at law or in
          equity.
                    Section 7.8. Confidentiality and Public Announcements.
                    The parties  recognize that  successful  consummation of the
          transactions  contemplated  by this  Agreement  may be dependent  upon
          confidentiality  with  respect to the matters  referred to herein.  In
          this  connection,  pending  public  disclosure  thereof,  each  of the
          parties  hereto  severally  and not jointly  agrees not to disclose or
          discuss such matters with anyone not a party to this Agreement  (other
          than its counsel, advisors,  corporate parents and Affiliates) without
          the prior  written  consent of the other  parties  hereto,  except for
          filings  required  pursuant  to the  Exchange  Act and the  rules  and
          regulations   thereunder  or  disclosures   its  counsel  advises  are
          necessary  in order to fulfill its  obligations  imposed by law or the
          requirements of any securities exchange. At all times during the terms
          of this  Agreement,  the parties  hereto will  consult with each other
          before  issuing or making any reports,  statements  or releases to the
          public with respect to this Agreement or the transactions contemplated
          hereby and will use good faith  efforts to agree on the text of public
          reports,  statements or releases.  For purposes of this  Section,  any
          consultation  or  consent  required  of from the  Stockholders  may be
          obtained from ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇.
                    Section 7.9. Governing Law.
                    This  Agreement  shall  be  governed  by  and  construed  in
          accordance  with the laws of the State of Delaware,  without regard to
          its rules of conflict of laws.
                    Section 7.10. Readings.
                    Headings of the Articles and Sections of this  Agreement are
          for the  convenience  of the  parties  only,  and  shall  be  given no
          substantive or interpretive effect whatsoever.
                    Section 7.11. Counterparts.
                    This  Agreement  may be executed  by the  parties  hereto in
          separate  counterparts,  each of which when so executed and  delivered
          shall be an original, but all such
                                       22
          counterparts  shall together  constitute one and the same  instrument.
          Each  counterpart may consist of a number of copies hereof each signed
          by less than all, but together signed by all of the parties hereto.
                                       23
                           IN WITNESS  WHEREOF,  the parties  hereto have caused
         this Principal Stockholder Agreement to be executed and delivered as of
         the date first written above.
                                   LORAL SPACE & COMMUNICATIONS LTD.
                                   By: /s/ ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                   Name:  ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                   Title:     Vice President, General
                                              Counsel and Secretary
                                   LORAL SATELLITE CORPORATION
                                   By: /s/ ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                   Name:  ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                   Title:     Vice President, General
                                              Counsel and Secretary
                                   ORION NETWORK SYSTEMS INC.
                                   By:  /s/ W. ▇▇▇▇ ▇▇▇▇▇
                                   Name:  W. ▇▇▇▇ ▇▇▇▇▇
                                   Title:  President and Chief Executive Officer
                                   BRITISH AEROSPACE SPACE SYSTEMS, INC.
                                   By:  /s/ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇
                                   Name:  ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇
                                   Title: Director
                                    BRITISH AEROSPACE HOLDINGS, INC.
                                    By:  /s/ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇
                                    Name:  ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇
                                    Title: Director
                                    FLEET VENTURE RESOURCES, INC.
                                       24
                                      By:/s/ ▇▇▇▇▇▇ ▇. ▇▇▇ ▇▇▇▇▇
                                      Name:▇▇▇▇▇▇ ▇. ▇▇▇ ▇▇▇▇▇
                                      Title:Chairman and Chief Executive Officer
                                      /s/ ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                     ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                     /s/ W. ▇▇▇▇ ▇▇▇▇▇
                                     W. ▇▇▇▇ ▇▇▇▇▇
                                    /s/ ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                    ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇
                                   /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇
                                   ▇▇▇▇▇▇ ▇. ▇▇▇▇
                                   /s/ ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                   ▇▇▇▇ ▇. ▇▇▇▇▇▇
                                       25
                                    EXHIBIT A
                           Common   Series A   Series B   Series C   Convertible
                           Stock    Preferred  Preferred  Preferred  Debentures
                           ------   ---------  ---------  ---------  -----------
British Aerospace Space
Systems, Inc.              729,921   _____      _____     3,007,770   3,571,429
British Aerospace
Holdings, Inc.
Warwick House, PO Box 87
Farnborough Aerospace
Centre
▇▇▇▇▇▇▇▇▇▇▇
▇▇▇▇▇, ▇▇▇▇▇▇▇
Telecopier No.:
(▇▇▇) ▇▇▇-▇▇▇-▇▇▇▇▇▇
▇▇▇▇ ▇. ▇▇▇▇▇▇          1,394,078   58,823     16,339      _____        _____
Medallion Enterprises,
LLC
▇▇▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇
▇▇▇▇▇ ▇▇.
▇▇▇▇▇ ▇▇▇
▇▇▇▇▇▇, ▇▇  ▇▇▇▇▇
Telecopier No.:
(▇▇▇) ▇▇▇-▇▇▇▇
W. ▇▇▇▇ ▇▇▇▇▇(1)(2)      _____        _____      _____     _____         _____
Orion
▇▇▇▇ ▇▇▇▇▇▇▇▇ ▇▇▇▇.
▇▇▇▇▇ ▇▇▇
▇▇▇▇▇▇▇▇▇, ▇▇  ▇▇▇▇▇
Telecopier No.: (▇▇▇) ▇▇▇-▇▇▇▇
▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇       352,355      58,823     16,339     _____         _____
▇▇▇▇▇▇ Communications,
Inc.
▇▇▇ ▇▇▇▇▇ ▇▇▇▇▇▇
▇▇▇▇ ▇▇▇▇▇
▇▇▇ ▇▇▇▇, ▇▇  ▇▇▇▇▇
Telecopier No.: (212) 956-
(▇▇▇) ▇▇▇-▇▇▇▇
                                       26
▇▇▇▇▇▇ ▇. ▇▇▇▇         207,260    _____         8,169     _____           _____
▇▇ ▇▇▇▇ ▇▇▇▇ ▇▇▇▇▇▇
▇▇▇▇▇ ▇▇▇
▇▇▇ ▇▇▇▇, ▇▇  ▇▇▇▇▇
Telecopier No.: 
(▇▇▇) ▇▇▇-▇▇▇▇
▇▇▇▇ ▇. ▇▇▇▇▇▇(2)      321,501   1,411            392     _____           _____
▇▇▇▇▇ ▇▇▇▇▇▇▇▇▇▇▇ ▇▇.
▇▇▇▇▇▇▇, ▇▇  ▇▇▇▇▇
Telecopier No.: 
(▇▇▇) ▇▇▇-▇▇▇▇
Fleet Venture         _____    588,234         155,194    _____           _____
Resources, Inc.        
c/o Fleet Equity Partners
RI MO F12C
▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇
▇▇▇▇▇▇▇▇▇▇, ▇▇  ▇▇▇▇▇
Telecopier No.: 
(▇▇▇) ▇▇▇-▇▇▇▇
     (1)  Does not include  shares  purchased  under Employee Stock Purchase
          Plan.
     (2)  Does not include shares beneficially owned by wife.
                                       27
                                    EXHIBIT B
                    Each of the  Stockholders  shall have the right to  transfer
          Shares to (a) any member of such  Stockholder's  immediate family, (b)
          any trust or similar  instrument for estate  planning  purposes or (c)
          any charitable organization, foundation or similar entities; provided,
          however,  such transfer may be made to any such  permitted  transferee
          only if such permitted transferee shall agree in writing to all of the
          terms,  conditions  and  restrictions  set  forth  in  this  Agreement
          regarding Shares received by such permitted transferee.
                                       28