<PAGE>
 
                                                                  EXHIBIT 10.52


                                      AGREEMENT

                                        AMONG

                                 COMSAT CORPORATION

                                COMSAT ARGENTINA S. A.

                                         AND

                    ICO GLOBAL COMMUNICATIONS (HOLDINGS) LIMITED

                       ICO GLOBAL COMMUNICATIONS HOLDINGS B.V.

                       ICO GLOBAL COMMUNICATIONS SERVICES INC.



                             Dated as of September 30, 1998
<PAGE>
 
                                    AGREEMENT


         This  Agreement  ("Agreement")  is made and entered into as of the
30th day of  September,1998  ("Effective  Date") by and among the following
parties:

                  COMSAT Corporation, a Washington D.C. corporation ("COMSAT
                  Corporation"),  with its  principal  place of business at
                  6560  Rock  Springs  Drive,  Bethesda,   Maryland  20817,
                  U.S.A.;

                  COMSAT ARGENTINA S. A., a sociedad anonime ("COMSAT
                  Argentina"), with its principal place of business at Carlos
                  Pellegrini 1363, 6th Floor, (1011) Buenos Aires, Argentina;

                  ICO Global  Communications  (Holdings) Limited, a Bermuda
                  corporation ("ICO Bermuda"),  with its principal place of
                  business at Clarendon  House, 2 Church Street,  Hamilton,
                  Bermuda;

                  ICO Global  Communications  Holdings  B.V., a Netherlands
                  corporation ("ICO Netherlands"), with its principal place
                  of business at  Drentestraat  20, 1083 HK Amsterdam,  The
                  Netherlands; and

                  ICO  Global  Communications  Services  Inc.,  a  Delaware
                  corporation ("ICO Services"), with its principal place of
                  business at The  Corporation  Trust Company,  1209 Orange
                  Street, Wilmington, Delaware, USA.

In consideration of the covenants contained in this Agreement,  the parties
hereto hereby agree as follows:


Section 1. Defined Terms.

Each of the terms set forth below,  when used in this Agreement,  will have
the definition set forth opposite such term:

Closing Date - The date to be agreed to by the  parties,  as more fully set
forth in Section 9 hereof.

Closing - The closing of the  transactions  contemplated  by this Agreement
pursuant to Section 9 hereof.
<PAGE>
 
COMSAT - COMSAT Corporation and COMSAT Argentina.

COMSAT  Entity - COMSAT  Corporation  and each of its direct  and  indirect
subsidiaries.

COMSAT Shares - The ICO Bermuda shares owned , respectively, on the date of
this Agreement by COMSAT  Corporation , being a total of 2,015,604  shares,
and COMSAT  Argentina , being a total of 1,226,007  shares,  as such shares
and the  number  thereof  may change to  reflect  any  changes in the share
capital of ICO  Bermuda or the  relationship  between  ICO  Bermuda and any
successor  entity at any time  during  the  period of  performance  of this
Agreement.

COMSAT Subscription Agreements - The Subscription Agreements dated January,
1995, and all amendments  thereto,  between COMSAT  Corporation  and COMSAT
Argentina,  respectively,  and a  predecessor  to ICO  Bermuda  and related
documents  and  similar  documents  between  any COMSAT  Entity and any ICO
Entity.

Distribution  Rights - All rights and  preferences  of any COMSAT Entity to
distribute  any  services  of any ICO Entity or  otherwise  act for any ICO
Entity anywhere in the world,  including but not limited to all such rights
and preferences that may have been granted or promised by any ICO Entity to
any COMSAT Entity,  including without  limitation,  any distribution rights
granted,  promised  or referred to in the  Information  Memorandum,  COMSAT
Subscription  Agreements,  actions of or  publications by any ICO Entity or
its Board of Directors, or employees or agents, or other agreement, whether
referred to as distribution  rights,  commercial rights,  gateway operator,
service  partner,   service  provider,  right  to  be  a  National  Service
Wholesaler,   National  Service  Retailer,   Service  Wholesaler,   Service
Retailer,  or otherwise . Nothing  herein shall be construed as  preventing
COMSAT from acting as a  non-exclusive  provider  to  International  Mobile
Satellite  Organization  ("Inmarsat")  for the  distribution  in the United
States of non-hand  held ICO products  for the  maritime  and  aeronautical
market  segments  or  non-hand  held  ICO  services  for the  maritime  and
aeronautical market segments.

ICO - ICO Bermuda,  ICO  Netherlands,  and ICO Services.  ICO Services is a
wholly  owned  subsidiary  of ICO  Netherlands,  which  is a  wholly  owned
subsidiary  of ICO Global  Communications  (Netherlands  Antilles)  N.V., a
Netherlands Antilles corporation, which is a wholly owned subsidiary of ICO
Global  Communications  (Operations) Limited, a Cayman Islands corporation,
which is a wholly owned subsidiary of ICO Bermuda.

ICO Entity - ICO Bermuda and each of its direct and indirect subsidiaries.

ICO   Services/USEI   Memorandum  of   Understanding   -  A  memorandum  of
understanding  in form and  substance  acceptable  to ICO Services  setting
forth in outline  form an  agreement  between  USEI and ICO  Services or an
entity  designated  by ICO Services  that would,  among other  things,  (i)
replace the Main  Agreement,  (ii) set forth USEI's consent to the transfer
by COMSAT to ICO  Services or an entity  designated  by ICO Services of the
USEI Agreement and USEI Lease
<PAGE>
 
without  condition at the request of ICO,  and (iii)  provide that the USEI
Agreement can be  terminated by COMSAT or, in the event the USEI  Agreement
has  been  transferred  to ICO  Services  or an  entity  designated  by ICO
Services,  by ICO  Services  or such  entity  without  cost to COMSAT,  ICO
Services, or such entity.

ICO  Cayman  Islands - ICO  Global  Communications  (Holdings)  Limited,  a
corporation organized under the laws of the Cayman Islands.

Information Memorandum - The Information Memorandum dated 16 September 1994
as  amended by the First  Addendum  thereto  dated 18 January  1995 and the
Second  Addendum  thereto dated 23 January 1995,  referred to in the COMSAT
Subscription  Agreement,  pursuant to which COMSAT  Corporation  and COMSAT
Argentina acquired the COMSAT Shares.

Interconnect Agreement - Interconnect Agreement dated March 5, 1997 between
COMSAT Corporation and ICO Netherlands and all amendments thereto, if any.

Licenses  -  All  licenses,  authorizations,  approvals,  and  permits  and
applications  therefor from any governmental  authority obtained or applied
for by (i) COMSAT Corporation in connection with the Interconnect Agreement
and the Main Agreement or either or in the  performance of its  obligations
thereunder or in connection with any Distribution Rights and/or (ii) COMSAT
Argentina in connection with any Distribution Rights.

Main  Agreement  - Main  Agreement  dated  March  5,  1997  between  COMSAT
Corporation and ICO Services and all amendments thereto, if any.

Main Agreement  Documents - All plans,  reports,  memoranda,  test results,
insurance  policies,  schedules and other  documents of  whatsoever  nature
created  or  obtained  by  COMSAT   Corporation  in  connection   with  the
performance of its  obligations  under the Main Agreement and  Interconnect
Agreement  or either and that are  reasonably  necessary  to  continue  the
installation,  operations,  maintenance, and interconnection of the SAN and
not subject to attorney-client privilege.

Main Agreement  Subcontracts  - All  agreements  entered into by any COMSAT
Entity with third parties pursuant to or in connection with the performance
of  COMSAT   Corporation's   obligations   under  the  Main  Agreement  and
Interconnect Agreement or either.

Parent Company  Guaranty - The Parent Company  Guaranty dated March 5, 1997
executed by ICO Cayman Islands in favor of COMSAT  Corporation  relating to
the Main Agreement and the Interconnect Agreement.

SAN - The Satellite Access Node constructed pursuant to the Main Agreement.
<PAGE>
 
Site Lease - The Lease of Earth  Station  Site dated April 4, 1997  between
COMSAT Corporation and USEI and all amendments  thereto, if any. Transition
Agreement - The Transition Agreement to be entered into by ICO Services and
COMSAT at the Closing, the form of which is attached hereto as Annex 1.

USEI - U.S. Electrodynamics, Inc., a corporation organized under the laws of
the state of Washington, USA.

USEI  Agreement  -  The  Agreement  dated  April  4,  1997  between  COMSAT
Corporation and USEI relating to the  construction and operation of the SAN
and all amendments thereto, if any.


Section 2. Payment.

At the Closing,  ICO Bermuda (or, at ICO  Bermuda's  direction,  any one or
more of the  parties  included  within the  definition  of ICO) will pay to
COMSAT,  by wire  transfer  to the bank  account  designated  in writing by
COMSAT,  in  immediately  available  funds,  the  aggregate  sum  of (i) in
consideration   for  terminating   the  Main  Agreement  and   Interconnect
Agreement,  U.S.  dollars  four  million  five  hundred  thousand  (U.S.  $
4,500,000),  and  (ii) an  additional  sum (in U.S.  dollars)  equal to all
amounts which the parties hereto agree are or will be owed by ICO to COMSAT
Corporation  through the Closing Date  pursuant to the Main  Agreement  and
Interconnect  Agreement that have not been paid as of such date,  which sum
shall be determined no ;later than five (5) days prior to the Closing.


Section 3.  Termination.

The  Interconnect  Agreement and Main Agreement  shall  terminate as of the
Closing  Date,  except  for  the  following  portions  of the  Interconnect
Agreement and Main Agreement which will remain in effect:

         (a) Sections 12,18, 19, and 34 of the Interconnect Agreement, and

         (b) Sections C10, H4, H5, H14, and H15.13 of the Main Agreement.


Section 4.  Transfers To ICO and Transition Agreement.

(A) At the  Closing,  COMSAT  Corporation  and ICO Services or other entity
designated  by ICO Services  will  execute and  deliver,  as of the Closing
Date, an Assignment and Assumption Agreement in the form attached hereto as
Annex 2, pursuant to which (i) COMSAT  Corporation  will assign or transfer
to ICO Services or other entity designated by ICO Services, all rights,
<PAGE>
 
titles,  and interests under the following,  and (ii) ICO Services or other
entity  designated  by ICO Services will assume the  obligations  of COMSAT
Corporation that arise after the Closing under the following, and (iii) ICO
Services  will  indemnify  COMSAT  against  all  claims  by  third  parties
(including  costs)  accruing  after the  Closing  in  connection  with such
assumed  obligations  and  reimburse  COMSAT for any taxes or fees that may
become  payable  as a result of such  assignment  or  transfer  of  rights,
titles, and interests under, the following:

         (1) Site Lease;

         (2) All Main Agreement Documents;

         (3) All Main Agreement Subcontracts;

         (4) All  Licenses (to the extent  transferable  and subject to any
         conditions applicable to transfer);

         (5) All rights, titles, and interests of COMSAT Corporation in and
         to all equipment, facilities, improvements,  structures, and other
         physical  property  and rights of  whatsoever  nature  acquired by
         COMSAT  Corporation  in  connection  with  or for  the  SAN  being
         constructed  pursuant to the Main Agreement or in connection  with
         the Interconnect Agreement; and

         (6) All Distribution Rights.

 (B) Except as otherwise agreed by the parties to facilitate the transition
services under the Transition Agreement, COMSAT Corporation will deliver to
ICO at or before the Closing the following  documents  which are defined in
the Main  Agreement  in whatever  state of  completion  or  readiness  such
documents may exist on the Closing Date and otherwise on an "as is" basis:

         As Built Plans
         Confidential Information (received from ICO in connection with the
         Main Agreement or Interconnect Agreement) 
         Plans
         Requisite Consents (to the extent  transferable  and  subject to any
         conditions of transfer applicable thereto) 
         Site Lease 
         Building Contract
         Copy of all Building Contractor  Insurance Policies in COMSAT's
         possession
         Warranties applicable to equipment installed pursuant to the Main
         Agreement

and all subcontracts, consulting agreements, utility agreements and similar
agreements  entered  into  by  COMSAT  Corporation  pursuant  to  the  Main
Agreement.

(C) COMSAT  Corporation  will  deliver to ICO at or before the  Closing the
following with respect to the Interconnect Agreement:
<PAGE>
 
         (1)  Confidential  Information,  as  defined  in the  Interconnect
              Agreement,   received  from  ICO  in   connection   with  the
              Interconnect Agreement,

         (2)  Names,  addresses,  telephone  numbers,  and  other  relevant
              information  relating all parties to which COMSAT Corporation
              provided quotes for ICO interconnect services, and

         (3)  Such other  information as may be in COMSAT's  possession and
              that  COMSAT  may  have  created  or  obtained  prior  to the
              Effective Date in order to perform its obligations  under the
              Interconnect  Agreement  ("ICO  Interconnect   Information"),
              provided  that  COMSAT  shall  not be  obligated  to  deliver
              quotes,  traffic  estimates  or  other  information  that  is
              derived from or represents a commingling of ICO  Interconnect
              Information and other COMSAT proprietary information (such as
              quotes  based on a bundling  of  forecasted  ICO  traffic and
              other non-ICO related traffic).

At the  request  of ICO  Services  at  any  time  during  the  term  of the
Transition  Agreement,  COMSAT will assign or otherwise transfer to a party
designated by ICO Services or amend or otherwise take all actions  required
to  substitute  such  party in  place of  COMSAT  as the  applicant  under,
whichever  ICO  Services  elects,   all  licenses  and  other  permits  and
authorizations  applied  for by COMSAT to the U.S.  Federal  Communications
Commission pursuant to the Main Agreement or Interconnect Agreement.

(D) At the Closing,  ICO Services and COMSAT will enter into the Transition
Agreement.

(E) If the Closing occurs, at the request of ICO Services at any time at or
prior to termination  of the Transition  Agreement and without the need for
further  documentation  other than the providing of written notice therefor
from ICO Services to COMSAT Corporation,  COMSAT Corporation shall transfer
to ICO  Services or other entity  designated  by ICO Services the rights of
COMSAT Corporation under the USEI Agreement, and ICO Services or such other
entity shall assume the  obligations of COMSAT  Corporation  under the USEI
Agreement that arise after such transfer.


Section 5. Registration Rights.

(A)      No ICO  Entity  will  object  to or  hinder  the  sale  by  COMSAT
         Corporation or COMSAT Argentina of any or all of the COMSAT Shares
         in a private sale not  prohibited by the rules or  regulations  of
         the U.S. Securities and Exchange  Commission ("SEC").  ICO Bermuda
         shall  promptly  register in its company  register the transfer of
         such shares  from COMSAT  pursuant to such sale from COMSAT to any
         purchaser designated by COMSAT pursuant to such sale provided such
         transfer is made in accordance  with, and not in violation of, the
         Bye-laws and/or Memorandum of Continuance of ICO Bermuda or any
         successor entity thereof and all applicable laws and regulations. 
         In furtherance thereof:
<PAGE>
 
         (1) ICO Bermuda hereby represents and warrants to COMSAT, which
             representation and warranty shall survive the execution,
             delivery, and any Closing hereunder, that as of the date of
             this Agreement there is nothing in the Bye-laws, Memorandum of
             Continuance or other charter document of ICO Bermuda that would
             restrict ICO Bermuda's ability to register such transfer of
             shares except for the provisions of Bye-laws 55, 56, and 57 of
             ICO Bermuda's Bye-laws, a copy of which are attached hereto
             as Annex 6.

         (2) Until the earlier of (i) January 1, 2000 or (ii) until  neither
             COMSAT  Corporation nor COMSAT  Argentina holds any COMSAT Shares,
             ICO Bermuda or any successor  entity shall remain current with all
             public  filings and other public  disclosures  required to be made
             with  the SEC  under  the  Securities  Exchange  Act of  1934,  as
             amended, and other applicable laws and regulations.

  (B) If  ICO  Bermuda  or  any  successor   entity   thereof  files  a
      registration statement with the SEC with respect to the offer and sale
      to the public in the  United  States of any of ICO  Bermuda's  (or any
      successor entity's) authorized and unissued ordinary shares, par value
      $0.01 per shares,  (the "ICO  Offered  Shares") at any time during the
      two year period commencing on January 1, 1999, then COMSAT Corporation
      and COMSAT Argentina will have the right to require ICO Bermuda or any
      successor entity thereof to include in such registration statement any
      COMSAT Shares owned by COMSAT  Corporation  and/or COMSAT Argentina as
      of the date of this  Agreement  which  COMSAT  Corporation  or  COMSAT
      Argentina  notifies  ICO Bermuda in writing that it desires to sell in
      the offering (the "COMSAT Offered Shares").  ICO Bermuda shall provide
      COMSAT at least  twenty days advance  written  notice of its intent to
      file any such  registration  statement  with the SEC, and COMSAT shall
      thereafter  have  fifteen  days to notify ICO Bermuda of its desire to
      sell  the  COMSAT  Offered  Shares   pursuant  to  such   registration
      statement.  The  aforementioned  right  to  require  any or all of the
      COMSAT Shares to be included in a registration  statement filed by ICO
      Bermuda or any  successor  entity with the SEC shall be subject to the
      following conditions:

      the  receipt by ICO Bermuda of a written  opinion of US legal  counsel
      reasonably  satisfactory to ICO to the effect that registration  under
      the  Securities  Act of 1933 is required  (because in the  judgment of
      such counsel there is no applicable  exemption) in connection with the
      transaction  contemplated  by COMSAT  Corporation or COMSAT  Argentina
      involving the COMSAT Offered Shares;
      in the  opinion of the lead  underwriter  for the  offering  (the lead
      underwriter  will be selected by ICO Bermuda) market  conditions would
      allow  for the  sale of both the ICO  Offered  Shares  and the  COMSAT
      Offered Shares;
      if any  ICO  shareholder  other  than COMSAT Corporation  or  COMSAT
      Argentina   to  which  ICO  Bermuda  has  given  demand  or  piggyback
      registration  rights as of the date of this  Agreement  (an "other ICO
      shareholder") demands that its ICO shares be registered,  ICO will not
      be required to include any COMSAT Offered  Shares in the registration
      unless  in the 
<PAGE>
 
     good  faith  opinion  of the lead  underwriter  market conditions  would
     allow for the sale of the ICO Offered  Shares,  the COMSAT Offered Shares
     and  the  shares  of  each  such  other  ICO shareholder;
     if as of the  closing  of the sale of the  shares  subject to any such
     registration  the lead  underwriter  deems it  necessary to reduce the
     number of shares  proposed to be sold,  any such  reduction will apply
     first to the COMSAT Offered Shares;
     COMSAT  proposes  no changes to the  underwriting  agreement  or other
     documentation required to be approved by COMSAT in connection with the
     offering (other than changes reasonably required to include the COMSAT
     Offered  Shares in such offering) if such  underwriting  agreement and
     other such  documentation  are  satisfactory  to ICO  Bermuda  and, if
     applicable,  each such other ICO shareholder;  provided such agreement
     will not (i)  obligate  COMSAT  to adhere to any  lock-up  period  for
     COMSAT  Offered  Shares not included in such  offering or (ii) provide
     for any  deferral  of payment  to COMSAT for the shares  sold by it in
     such offering; and
     COMSAT will bear its legal fees and its related costs  (including  the
     proportionate  share  of  any  NASD  and  SEC  filing  fees)  and  the
     underwriter  fees and  discounts  attributable  to the COMSAT  Offered
     Shares.


         In any  such  offering  ICO  Bermuda  will  enter  into  customary
underwriting arrangements, supply information, make requests, and otherwise
use reasonable  commercial  efforts,  including (except as indicated above)
the payment of necessary fees for the preparation,  filing, and printing of
the  registration  statement  and  exhibits  thereto  (including  copies of
preliminary  and  final  prospectuses  and to obtain  all  legal  opinions,
auditors  consents,  and comfort letters,  and participate in and cooperate
with due  diligence  activities  and any "road shows" or similar  marketing
efforts if requested by the lead  underwriter  to facilitate  the offering.
ICO Bermuda  will deliver or cause to be delivered to COMSAT such number of
copies as may be reasonably  requested by COMSAT of  preliminary  and final
registration   statements  and  prospectuses   (including  any  revised  or
supplemental  prospectuses)  and  except as  indicated  above  will pay all
expenses in connection with the  registration of the COMSAT Offered Shares.
ICO  Bermuda and any  successor  entity  thereof  will  indemnify  and hold
harmless   COMSAT  and  its   officers,   directors,   employees,   agents,
representatives   and  underwriters   against  claims,   losses,   damages,
liabilities  and  expenses  (including  attorneys  fees and sums payable in
satisfaction of judgments or decrees) resulting from or attributable to any
untrue  statement  of a material  fact or  allegedly  untrue  statement  or
alleged  omission to state  therein any material fact required to be stated
or necessary  to make any  statements  not  misleading  except  insofar as the
information  shall have been  furnished in writing to ICO Bermuda by COMSAT
Corporation or COMSAT  Argentina,  or other violations or non-compliance by
ICO Bermuda with applicable laws or regulations or contractual obligations,
relating to such offering,  and if such  indemnification  is deemed void as
against  public  policy  shall  contribute  to COMSAT such sums as would be
equal  to any  payments  otherwise  payable  to  COMSAT  and its  officers,
directors, employees, agents, representatives and underwriters to indemnify
and hold harmless each of them pursuant to this Section 6(B).
<PAGE>
 
Section 6. Representations.

(A) COMSAT  Corporation  hereby covenants and agrees that the copies of the
Site Lease,  USEI  Agreement,  and Main Agreement  Subcontracts  heretofore
delivered to ICO are the  originals or true copies of the originals of such
documents and that such  documents at the Closing will be in full force and
effect and that COMSAT will not be in breach of its obligations thereunder.
COMSAT   Corporation   hereby  represents  and  warrants  that  (i)  COMSAT
Corporation  is the  owner  free  and  clear  of  all  liens,  claims,  and
encumbrances  of the rights  attributed  to COMSAT  Corporation  under (and
subject to the terms of) the Interconnect Agreement,  Main Agreement,  Site
Lease, USEI Agreement,  and Main Agreement  Subcontracts,  and (ii) neither
COMSAT   Corporation  nor  COMSAT   Argentina  has  assigned  or  otherwise
transferred  or  encumbered or entered into any  agreements  with any third
party that creates any rights, liens, claims, and encumbrances on or to the
Distribution Rights, and (iii) COMSAT Corporation and COMSAT Argentina each
has the authority and power to enter into this Agreement and to perform its
obligations hereunder.

(B) ICO hereby represents and warrants to COMSAT and agrees that (i) ICO is the
owner free and clear of all liens,  claims,  and encumbrances of the rights
attributed to ICO under the  Interconnect  Agreement and Main Agreement and
(ii) ICO has the  authority  and power to enter into this  Agreement and to
perform its obligations hereunder, (iii) the information set forth on Annex
4 hereto with respect to registration  rights granted to other shareholders
of ICO Bermuda is true and correct,  and (iv) ICO Bermuda has  succeeded to
and is fully  liable for the  obligations  of its  predecessor,  ICO Cayman
Islands, under the Parent Company Guaranty.

(C) At the Closing, COMSAT and ICO will each execute and deliver to the other a
Representation  and Warranty Agreement in the form attached hereto as Annex
5,  pursuant to which each such party makes,  as of the Closing  Date,  the
same  covenants,  representations,  and warranties as are set forth in this
Section 6.


Section 7. Mutual Releases.

At the Closing, COMSAT and ICO will execute and deliver a Mutual Release in
the form attached hereto as Annex 3, pursuant to which COMSAT will release,
or will cause to be released,  each ICO Entity from,  and ICO will release,
or will cause to be  released,  each  COMSAT  Entity  from,  all claims and
causes of  action  whatsoever  related  to the  Distribution  Rights or any
rights  or  warranties  related  to the Main  Agreement,  the  Interconnect
Agreement,  and the Main Agreement  Subcontracts (except as provided for in
Section 3 hereto)  which any COMSAT  Entity or ICO Entity,  as the case may
be, may have against any ICO Entity or COMSAT  Entity,  as the case may be,
and COMSAT will agree not to assert (and will cause each COMSAT  Entity not
to assert) against any ICO Entity
<PAGE>
 
or any other  person or entity  not a party to this  Agreement  any  claims
arising out of or connected with the Distribution Rights and/or any matters
contained in the letter from Crowell & Moring to ICO Bermuda dated 15 April
1998 and the draft Writ sent to ICO Bermuda on 9 June 1998.


Section 8. USEI Transactions.

Forthwith after the Effective Date, COMSAT will (i) notify USEI that COMSAT
and ICO have entered into this  Agreement  and that COMSAT has no objection
to USEI  conducting  negotiations  with ICO Services in an attempt to reach
agreement  on  an  ICO  Services/USEI   Memorandum  of  Understanding  (ii)
cooperate with ICO to the extent  reasonably  requested in ICO's efforts to
enter into the ICO Services/USEI Memorandum of Understanding and (iii) seek
the written consent of USEI to assign the USEI Agreement to ICO Services or
any entity designated by ICO Services.

(B)  Forthwith  after the  Effective  Date,  ICO  Services or other  entity
designated  by ICO will  use  good  faith  efforts  to  enter  into the ICO
Services/USEI  Memorandum of Understanding not later than 60 days after the
Effective Date.


Section 9. Closing.

(A) Unless  otherwise  hereafter  mutually  agreed in  writing  by the  parties
hereto,  the Closing Date will be a date  acceptable  to COMSAT and ICO not
later than 30 days after the  Effective  Date;  PROVIDED  THAT the  Closing
shall  not  occur on such date  unless  on or prior  thereto  either of the
following  conditions  has  occurred (i) USEI and ICO Services or an entity
designated  by  ICO  Services  have  entered  into  the  ICO  Services/USEI
Memorandum of  Understanding or (ii) USEI has given (and not withdrawn) its
consent  for COMSAT to assign the USEI  Agreement  to ICO  Services  or any
entity designated by ICO Services. If neither of the conditions referred to
in (i) or (ii) of this Section 9(A) has occurred within such 30 day period,
the Closing Date shall be deferred to a date  acceptable  to ICO and COMSAT
not later than 60 days after the Effective  Date;  PROVIDED THAT if neither
of the  conditions  referred  to in (i) or (ii) of this  Section  9(A)  has
occurred on or before 60 days after the Effective  Date, each of COMSAT and
ICO will have the  right to  terminate  this  Agreement  by giving  written
notice thereof to the other party.  If this Agreement is so terminated,  no
party hereto will have any right or obligation under this Agreement.

(B) The Closing and the  performance by the parties hereto of their  respective
obligations  under this Agreement at the Closing are  conditional  upon the
occurrence or fulfillment prior to the Closing of the conditions to Closing
expressly set forth in this Agreement and the performance by COMSAT and ICO
of their respective obligations at the Closing.

(C) The  Closing  will occur at 10 o'clock  AM on the  Closing  Date in the
offices of COMSAT Corporation at 6560 Rock Springs Drive, Bethesda MD 
20817 U.S.A. At the Closing each party
<PAGE>
 
hereto will execute and deliver the  documents  required and take the other
action  required to be taken to fulfill at the Closing all the  obligations
of such part under this Agreement.


Section 10. General.

(i)      All notices  sent by COMSAT or ICO to the other party will be sent
         by telefax or  delivered  to the  address for such party set forth
         below:

         Notices to COMSAT                          Notices to ICO

         COMSAT Corporation                         ICO Global Communications
         6560 Rock Springs Drive                    1 Queen Caroline Street
         Bethesda MD 20817                          Hammersmith London W6 9 BN
         USA                                        United Kingdom
         Attention: General Counsel                 Attention: General Counsel
         Fax. No. 301-214-7145                      Fax No.  44-181-741-0851

(ii)     No party  hereto  will  have  any  right to  assign  or  otherwise
         transfer  or  encumber  its  rights  or  obligations   under  this
         Agreement.

(iii)    This Agreement  shall be governed by and interpreted and construed
         in accordance with English Law; provided, however, that all suits,
         claims, actions,  proceedings or disputes arising or brought under
         Section  5  "Registration  Rights"  of  this  Agreement  shall  be
         governed by and  interpreted  and construed in accordance with the
         laws of the State of New York without  regard to conflicts of laws
         principles.

(iv)     The parties agree that the courts of England are to have exclusive
         jurisdiction  to settle any dispute  which may arise in connection
         with the validity,  effect,  interpretation or performance of this
         Agreement or otherwise  arising out of or in connection  with this
         Agreement or any of its terms.

(v)      At the request of any party  hereto,  all the parties  hereto will
         execute and deliver  all other  documents  that may be required to
         give effect to the agreements contemplated by this Agreement.

(vi)     The  Parent  Company  Guaranty  will  remain in  effect  after the
         Closing and will cover only (i) the  obligations  of ICO  Services
         under the Transition  Agreement,  and (ii) the  obligations of ICO
         under the Main Agreement and Interconnect Agreement that remain in
         effect after the Closing  pursuant to Section 3 and the Assignment
         and Assumption Agreement hereof.
<PAGE>
 
(vii)    It is  expressly  agreed and  acknowledged  by each of the parties
         that the execution and  performance  of this Agreement is not, and
         is  not  to be  construed  as,  any  admission  whatsoever  of any
         liability on the part of any of the parties to this Agreement.

(viii)   Except to the extent  required  by  applicable  law and to parties
         with whom any party has  contracted  or may  contract or intend to
         contract  with  respect to any of the matters that are the subject
         of this  Agreement,  no party hereto shall make any  announcement,
         news release,  or other public statement  regarding this Agreement
         or its subject matter without prior written  approval of the other
         parties, such approval not to be unreasonably withheld or delayed.

(ix)     This  Agreement  sets out the entire  agreement and  understanding
         between  the  parties  in respect  of the  subject  matter of this
         Agreement. It is agreed that:

         (a)      No party  hereto  has  entered  into  this  Agreement  in
                  reliance on any  representation,  warranty or undertaking
                  of any  other  party  which is not  expressly  set out or
                  referred to in this Agreement,

         (b)      No  party  shall  have  any  remedy  in  respect  of  any
                  misrepresentation  or untrue  statement made by any other
                  party which is not contained in this Agreement, and

         (c)      This clause  shall not exclude any  liability  for fraudulent
                  misrepresentation.

(x)      At and after the Closing,  each of COMSAT and ICO will execute and
         deliver all documents and take all actions required to give effect
         to the agreements of the parties set forth in this Agreement.

(xi)     Attached  hereto and hereby made a part  hereof are the  following
         Annexes:  
         Annex 1. Form of Transition  Agreement  
         Annex 2. Form of Assignment  and  Assumption  Agreement  
         Annex 3. Form of Mutual Release
         Annex 4. Information Relating to Registration Rights granted to other
                    Shareholders of ICO Bermuda
         Annex 5. Form of Representation and Warranty Agreement
         Annex 6. Bye-laws 55, 56, and 57 of ICO Bermuda
<PAGE>
 
IN WITNESS WHEREOF,  the parties hereto have entered into this Agreement on
the date first mentioned above.


COMSAT Corporation                               ICO GLOBAL COMMUNICATIONS
                                                 (HOLDINGS) LIMITED



By: /s/ John Mattingly                           By: /s/ Olof Lundberg
    Name:  John Mattingly                        Name:  Olof Lundberg
    Title: President, COMSAT                     Title: CEO
           Satellite Services


COMSAT ARGENTINA S. A.                           ICO GLOBAL COMMUNICATIONS
                                                 HOLDINGS B.V.



By: /s/ Luis Valencia                            By: /s/ Olof Lundberg
    Name:  Luis Valencia                         Name: Olof Lundberg
    Title: President of the Board of Directors   Title: CEO



                                                 ICO GLOBAL COMMUNICATIONS
                                                 SERVICES INC.



                                                 By: /s/ Olof Lundberg
                                                 Name: Olof Lundberg
                                                 Title: CEO