ORBCOMM GLOBAL L P
8-K, 2000-02-04
RADIOTELEPHONE COMMUNICATIONS
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<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                ----------------

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported)            JANUARY 26, 2000
                                                            ----------------


                              ORBCOMM GLOBAL, L.P.
- --------------------------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

          DELAWARE                  333-11149          54-1698039
- --------------------------------------------------------------------------------
(State or Other Jurisdiction       (Commission       (IRS Employer
      of Incorporation)            File Number)      Identification No.)


                         2455 HORSE PEN ROAD, SUITE 100
                             HERNDON, VIRGINIA 20171
- --------------------------------------------------------------------------------
               (Address of Principal Executive Offices) (Zip Code)

Registrant's telephone number, including area code:        (703) 406-6000
                                                           --------------
                                 NOT APPLICABLE
- --------------------------------------------------------------------------------
          (Former Name or Former Address, if Changed Since Last Report)


<PAGE>   2


ITEM 1.  CHANGES IN CONTROL OF REGISTRANT.

            On January 26, 2000, the registrant, Teleglobe Mobile Partners
("Teleglobe Mobile") and Orbital Communications Corporation ("OCC"), the
registrant's partners, Teleglobe Inc. ("Teleglobe") and Orbital Sciences
Corporation ("Orbital") entered into an Omnibus Agreement dated as of January 1,
2000 (the "Omnibus Agreement"). Pursuant to the Omnibus Agreement and effective
as of January 1, 2000, Teleglobe Mobile became the registrant's sole general
partner and acquired a majority interest in the registrant in accordance with
the formula set forth in the Amended and Restated Partnership Agreement of the
registrant. OCC converted its general partner interest into a limited partner
interest. Assuming closing by February 25, 2000 of certain transactions as
contemplated in the Omnibus Agreement, Teleglobe Mobile and OCC will own
approximately 60% and 40%, respectively, of the registrant. As of January 26,
2000, Teleglobe Mobile held approximately a 65% equity interest in the
registrant, with the balance of the equity interests in the registrant held by
OCC. Each of Teleglobe Mobile and OCC remains a limited partner of the
registrant.

            The funds used by Teleglobe Mobile to increase its equity interest
in the registrant were obtained by Teleglobe Mobile from the proceeds of
intercompany loans and/or equity contributions from affiliates of Teleglobe to
Teleglobe Mobile.

            On January 27, 2000, Teleglobe and Orbital issued a joint press
release regarding the transaction.

ITEM 7. FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

     (c) EXHIBITS.

            3.1     Amended and Restated Partnership Agreement of ORBCOMM
                    Global, L.P. dated as of January 1, 2000

           10.1     Omnibus Agreement dated as of January 1, 2000 among Orbital
                    Sciences Corporation, Orbital Communications Corporation,
                    Teleglobe Inc., Teleglobe Mobile Partners and ORBCOMM
                    Global, L.P.

           99.1     Press Release dated January 27, 2000


                                       2
<PAGE>   3


SIGNATURES

            Pursuant to the requirements of the Securities Exchange Act of 1934,
as amended, the Registrant has duly caused this Report to be signed on its
behalf by the undersigned thereunto duly authorized.

                                          ORBCOMM GLOBAL, L.P.

Date:  February 2, 2000                   By:  /s/ Scott L. Webster
                                             -----------------------------------
                                             Scott L. Webster Chairman and Chief
                                             Executive Officer



                                       3

<PAGE>   1
                                                                    Exhibit 3.1




             AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP


                                       OF


                              ORBCOMM GLOBAL, L.P.
<PAGE>   2

             AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP
                                       OF
                              ORBCOMM GLOBAL, L.P.

                               Table of Contents

<TABLE>
<CAPTION>
                                                                                   Page
                                                                                   ----
<S>                                                                                  <C>
SECTION 1  THE LIMITED PARTNERSHIP.....................................................1
         1.1.  Formation...............................................................1
               ---------
         1.2.  Name....................................................................2
               ----
         1.3.  Nature of the Business..................................................2
               ----------------------
         1.4.  Principal Office........................................................2
               ----------------
         1.5.  Fiscal Year.............................................................2
               -----------
         1.6.  Delaware Office; Agent for Service of Process...........................2
               ---------------------------------------------
SECTION 2  DEFINITIONS.................................................................2
         2.1.  Adjusted Property.......................................................2
               -----------------
         2.2.  Affiliate...............................................................3
               ---------
         2.3.  Agreement...............................................................3
               ---------
         2.4.  Business Day............................................................3
               ------------
         2.5.  Capital Account.........................................................3
               ---------------
         2.6.  Carrying Value..........................................................3
               --------------
         2.7.  Certificate ............................................................3
               -----------
         2.8.  Definitive Agreements ..................................................3
               ---------------------
         2.9.  Delaware Act ...........................................................3
               ------------
         2.10.  Event of Withdrawal....................................................3
                -------------------
         2.11.  General Partner........................................................4
                ---------------
         2.12.  Indemnified Party......................................................4
                -----------------
         2.13.  Limited Partner........................................................4
                ---------------
         2.14.  Master Agreement.......................................................4
                ----------------
         2.15.  Net Income and Net Loss................................................4
                -----------------------
         2.16.  Net Value..............................................................4
                ---------
         2.17.  Omnibus Agreement......................................................4
                -----------------
         2.18.  Original Agreement.....................................................4
                ------------------
         2.19.  Participation Percentage...............................................4
                ------------------------
         2.20.  Partners...............................................................4
                --------
         2.21.  Partnership............................................................4
                -----------
         2.22.  Partnership Interest...................................................5
                --------------------
         2.23.  Partnership Year ......................................................5
                ----------------
         2.24.  Recapture Income.......................................................5
                ----------------
         2.25.  Restatement Date.......................................................5
                ----------------
         2.26.  Section................................................................5
                -------
</TABLE>

                                      -i-
<PAGE>   3

<TABLE>
<S>                                                                                  <C>
         2.27.  Tax Matters Partner.......................................................5
                -------------------
         2.28.  Transfer..................................................................5
                --------
         2.29.  Unrealized Gain...........................................................5
                ---------------
         2.30.  Unrealized Loss...........................................................5
                ---------------
SECTION 3  PARTNERSHIP INTERESTS AND CAPITAL CONTRIBUTIONS................................5
         3.1.  Partnership Interests......................................................5
               ---------------------
         3.2.  Withdrawal of Capital Contributions........................................6
               -----------------------------------
         3.3.  Loans......................................................................6
               -----
         3.4  Additional Capital Contributions............................................6
              --------------------------------
SECTION 4  DISTRIBUTIONS..................................................................7
         4.1.  Distributions..............................................................7
               -------------
         4.2.  Minimum Distribution.......................................................8
               --------------------
         4.3.  Nature of Distributions....................................................8
               -----------------------
         4.4.  Tax Payments...............................................................8
               ------------
SECTION 5  PARTNERS' ACCOUNTS; ALLOCATION OF PARTNERSHIP INCOME AND EXPENSES..............8
         5.1.  Maintenance of Capital Accounts............................................8
               -------------------------------
         5.2.  Allocations of Net Income and Net Loss....................................11
               --------------------------------------
SECTION 6 MANAGEMENT.....................................................................14
         6.1.  Authority of General Partner .............................................14
               ----------------------------
         6.2.  OCC Approval..............................................................15
               ------------
         6.3.  OCC Approval..............................................................15
               ------------
         6.4.  OCC Approval..............................................................16
               ------------
         6.5.  Meetings .................................................................17
               --------
         6.6.  Representation at Meetings; Reimbursement.................................17
               -----------------------------------------
         6.7.  Designation of Officers...................................................17
               -----------------------
         6.8.  Removal of Officers ......................................................18
               -------------------
SECTION 7  AGREEMENTS AND AUTHORITY OF THE PARTNERS......................................18
         7.1.  Rights and Duties of Limited Partners.....................................18
               -------------------------------------
         7.2.  Restrictions on General Partner's Authority; Loss Sharing.................19
               ---------------------------------------------------------
         7.3.  Exculpation...............................................................19
               -----------
         7.4.  Other Activities..........................................................19
               ----------------
SECTION 8  ACCOUNTS......................................................................20
         8.1.  Books.....................................................................20
               -----
         8.2.  Partners' Accounts........................................................20
               ------------------
         8.3.  Certificates, Reports, Returns and Audits.................................20
               -----------------------------------------
         8.4.  Auditors..................................................................21
               --------
         8.5.  Review Policies...........................................................21
               ---------------
SECTION 9  TRANSFERS OF PARTNERSHIP INTERESTS; WITHDRAWALS...............................21
         9.1.  Transfer of Partnership Interests.........................................21
               ---------------------------------
         9.2.  Prohibited Transfers Void.................................................21
               -------------------------
         9.3.  Withdrawal of Partners....................................................21
               ----------------------
</TABLE>

                                     -ii-



<PAGE>   4

<TABLE>
<S>                                                                                  <C>
SECTION 10  DISSOLUTION..................................................................22
         10.1.  Events of Dissolution....................................................22
                ---------------------
         10.2.  Final Accounting.........................................................22
                ----------------
         10.3.  Liquidation..............................................................22
                -----------
         10.4.  Distribution in Kind ....................................................22
                --------------------
         10.5.  Cancellation of Certificate..............................................22
                ---------------------------
SECTION 11  NOTICES......................................................................23
         11.1.  Method of Notices........................................................23
                -----------------
         11.2.  Routine Communications...................................................23
                ----------------------
         11.3.  Computation of Time......................................................23
                -------------------
SECTION 12  GENERAL PROVISIONS...........................................................23
         12.1.  Entire Agreement.........................................................23
                ----------------
         12.2.  Amendment; Waiver........................................................23
                -----------------
         12.3.  Governing Law............................................................24
                -------------
         12.4.  Binding Effect...........................................................24
                --------------
         12.5.  Counterparts.............................................................24
                ------------
         12.6.  Separability.............................................................24
                ------------
         12.7.  Headings.................................................................24
                --------
         12.8.  Gender and Number........................................................24
                -----------------
         12.9.  Waiver of Partition and Dissolution......................................24
                -----------------------------------
         12.10.  Coordination with Master Agreement......................................24
                 ----------------------------------
         12.11.  Dispute Resolution......................................................24
                 ------------------
</TABLE>



                                     -iii-

<PAGE>   5
             AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP
                                       OF
                              ORBCOMM GLOBAL, L.P.


         THIS AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP (the
"Agreement") of ORBCOMM GLOBAL, L.P. (the "Partnership") is made and entered
into as of January 1, 2000 by and between TELEGLOBE MOBILE PARTNERS, a Delaware
general partnership ("Teleglobe Mobile"), as general partner (the "General
Partner"), and ORBITAL COMMUNICATIONS CORPORATION, a Delaware corporation
("OCC"), and Teleglobe Mobile as limited partners (the "Limited Partners").
The General Partner and the Limited Partners are collectively referred to
herein as the "Partners".  This Agreement amends and restates the Restated
Agreement of Limited Partnership of ORBCOMM Global, L.P. dated September 15,
1995, as amended by Amendment No. 1 to Restated Agreement of Limited
Partnership of ORBCOMM Global, L.P. dated as of December 2, 1996 (the "1995
Agreement") and by the Omnibus Agreement dated as of January 1, 2000 entered
into among the Partners, Orbital Sciences Corporation, a Delaware corporation
("Orbital"), and Teleglobe Inc., a Canadian corporation ("Teleglobe"), and the
Partnership (the "Omnibus Agreement").

         WHEREAS, the Partnership was organized, in accordance with the
provisions of the Delaware Act (as hereinafter defined), by the filing of a
Certificate of Limited Partnership with the Secretary of State of the State of
Delaware (the "Certificate") pursuant to Section 17-201 of the Delaware Act;

         WHEREAS, upon the filing of the Certificate, the Partners entered into
an Agreement of Limited Partnership dated as of June 30, 1993 (the "Original
Agreement") and the Partnership entered into agreements with OCC, Orbital and
Teleglobe for the development, construction, operation and marketing of the
ORBCOMM System (as hereinafter defined); and

         WHEREAS, pursuant to the terms of the Omnibus Agreement, the Partners
revised the terms of the 1995 Agreement setting forth their agreements with
respect to the conduct of the business of the Partnership and each of their
rights and obligations as Partners.

         NOW THEREFORE, the Partners, in consideration of the foregoing
premises, the agreements and covenants contained herein and other good and
valuable consideration received, the receipt and sufficiency of which are
hereby acknowledged, hereby agree as follows:

                                   SECTION 1

                            THE LIMITED PARTNERSHIP

         1.1.    Formation.  The Partnership was formed and is being continued
as a limited partnership pursuant to the Delaware Act.





<PAGE>   6
         1.2.    Name.  The name of the Partnership shall be ORBCOMM Global,
L.P., but the business of the Partnership may be conducted under any other name
agreed to by the General Partner and, in such event, the General Partner shall
notify the Partners of such name change promptly thereafter.

         1.3.    Nature of the Business.  The business of the Partnership shall
be to engage in the development, construction, operation and marketing of a
global digital satellite communications system of low-Earth orbit satellites
intended to provide two-way data and message communications and position
determination services throughout the world (the "ORBCOMM System"), to contract
with the General Partner and other Persons for the development, construction
and operation of the spacecraft, the launch vehicles, the master network
control center, satellite control center, United States gateway Earth stations
and any other components of the ORBCOMM System, to market or arrange for the
marketing of the services of the ORBCOMM System, to engage in research and
development in connection therewith and to do all things necessary, appropriate
or advisable in connection with each of the foregoing.

         1.4.    Principal Office.  The location of the principal office of the
Partnership shall be 2455 Horse Pen Road, Herndon, Virginia 20171 or at such
other location as may be selected from time to time by the General Partner,
subject to Article 8.5 of the Omnibus Agreement.  If the General Partner
changes the location of the principal office of the Partnership, the Partners
shall be notified promptly thereafter.  The Partnership may maintain such other
office(s) at such other place(s) as the General Partner deems advisable.

         1.5.    Fiscal Year.  The fiscal year of the Partnership, and the
taxable year of the Partnership for United States Federal income tax purposes,
shall be the calendar year (the "Partnership Year").

         1.6.    Delaware Office; Agent for Service of Process.  The name of
the registered agent for service of process on the Partnership is Corporation
Service Company, 1013 Centre Road, Wilmington, Delaware.  The address of the
Partnership's registered office in the State of Delaware shall be the address
of its registered agent.

                                   SECTION 2

                                  DEFINITIONS

         Except as otherwise defined herein, all terms used herein have the
meanings specified in the Master Agreement (as hereinafter defined).  The
following defined terms used in this Agreement shall have the respective
meanings specified below.

         2.1.    Adjusted Property.  "Adjusted Property" means property the
Carrying Value of which has been adjusted pursuant to Section 5.1(d).





                                      -2-
<PAGE>   7
         2.2.    Affiliate.  "Affiliate" means, with respect to any Person, any
Person directly or indirectly controlled by, or under common control with, such
Person.

         2.3.    Agreement.  "Agreement" shall have the meaning ascribed to such
term in the recitals hereto.

         2.4.    Business Day.  "Business Day" means any day excluding
Saturday, Sunday and any other day which in Washington, D.C.  or Montreal,
Quebec is a legal holiday or a day on which financial institutions are
authorized by law or by local proclamation to close.

         2.5.    Capital Account.  The "Capital Account" of a Partner means the
account maintained for such Partner in accordance with the provisions of
Section 5.1.

         2.6.    Carrying Value.  "Carrying Value" means (a) with respect to
Contributed Property, the fair value of such property at the time of its
contribution to the Partnership reduced (but not below zero) by all
amortization, depreciation and cost recovery deductions charged to the
Partners' Capital Accounts pursuant to Section 5 with respect to such property,
and (b) with respect to any other property, the adjusted basis of such property
for United States Federal income tax purposes, as of the time of determination,
subject to those adjustments specified in the following sentence.  The Carrying
Value of any property shall be adjusted from time to time in accordance with
Sections 5.1(c), 5.1(d) and 5.1(e) and to reflect changes, additions or other
adjustments to the Carrying Value for dispositions, acquisitions or
improvements of Partnership property, as deemed appropriate by the General
Partner, and in a manner consistent with United States Federal income tax
principles.

         2.7.    Certificate.  "Certificate" shall have the meaning ascribed to
such term in the recitals hereto.

         2.8.    Definitive Agreements.  "Definitive Agreements" means this
Agreement, the Omnibus Agreement, the Master Agreement, the ORBCOMM System
Procurement Agreement dated as of September 12, 1995 entered into between the
Partnership and Orbital, the ORBCOMM Procurement Agreement dated as of February
1, 1999 entered into between the Partnership and Orbital, the ORBCOMM System
Construction Agreement, the Proprietary Information and Non-Competition
Agreement, and other agreements entered into pursuant to the terms of the
Omnibus Agreement, as such agreements may have been amended or restated or may
be amended or restated in the future.

         2.9.    Delaware Act.  "Delaware Act" means the Delaware Revised
Uniform Limited Partnership Act, 6 Del. Code Ann. tit. 6, Sections 17-101, et.
seq., as it may be amended from time to time, and any successor thereto.

         2.10.   Event of Withdrawal.  "Event of Withdrawal" shall have the
meaning ascribed to such term in Section 10.1(b).





                                      -3-
<PAGE>   8
         2.11.   General Partner.  "General Partner" shall have the meaning
ascribed to such term in the recitals hereto.

         2.12.   Indemnified Party.  "Indemnified Party" shall have the meaning
ascribed to such term in Section 7.3.

         2.13.   Limited Partner.  "Limited Partner" shall have the meaning
ascribed to such term in the recitals hereto.

         2.14.   Master Agreement.  "Master Agreement" means the agreement
between Orbital, OCC, Teleglobe Mobile, and Teleglobe, dated as of June 30,
1993 and titled the "Master Agreement" as amended and restated from time to
time.

         2.15.   Net Income and Net Loss.  "Net Income" or "Net Loss" means an
amount equal to the Partnership's taxable income or taxable loss for a relevant
period, adjusted as provided herein. Net Income and Net Loss shall be
determined in accordance with Section 703(a) of the Code (for this purpose, all
items of income, gain, loss or deduction required to be stated separately
pursuant to Section 703(a)(1) of the Code shall be included in taxable income
or loss), and adjusted as provided in Sections 5.1(b) through (e), and further
adjusted to reflect any adjustments resulting from amended returns, claims for
refund and tax audits.

         2.16.   Net Value.  "Net Value" means, in the case of a contribution
of assets, the fair value of assets contributed to the Partnership reduced by
the outstanding balance of any indebtedness either assumed by the Partnership
upon such contribution or to which such assets are subject when contributed
and, in the case of a distribution of assets, the fair value of assets
distributed by the Partnership reduced by the outstanding balance of any
Partnership indebtedness assumed by the Partner receiving such distribution or
any indebtedness to which such distributed property is subject, as such fair
value is determined by the General Partner using such reasonable methods of
valuation as they in their sole discretion deem appropriate.

         2.17.   Omnibus Agreement.  "Omnibus Agreement" shall have the meaning
ascribed to such term in the recitals hereto.

         2.18.   Original Agreement.  "Original Agreement" shall have the
meaning ascribed to such term in the recitals hereto.

         2.19.   Participation Percentage.  The "Participation Percentage" of a
Partner shall be the portion of such Partner's Partnership Interest described
as such in Section 3.1.

         2.20.   Partners.  "Partners" shall have the meaning ascribed to such
term in the recitals hereto.

         2.21.   Partnership.  "Partnership" shall have the meaning ascribed to
such term in the recitals hereto.



                                      -4-
<PAGE>   9

         2.22.   Partnership Interest.  The "Partnership Interest" of a Partner
shall be the total interest of such Partner in the Partnership.

         2.23.   Partnership Year.  "Partnership Year" shall have the meaning
ascribed to such term in Section 1.5.

         2.24.   Recapture Income.  "Recapture Income" means any gain
recognized by the Partnership (but computed without regard to any adjustment
required by Section 734 or 743 of the Code) upon the disposition of any
property or asset of the Partnership that does not constitute capital gain for
United States Federal income tax purposes because such gain represents the
recapture of deductions or reductions in basis for tax credits previously taken
with respect to such property or assets.

         2.25.   Restatement Date.  "Restatement Date" means January 1, 2000.

         2.26.   Section.  Except as otherwise provided herein, "Section" means
a section of this Agreement.

         2.27.   Tax Matters Partner.  "Tax Matters Partner" shall have the
meaning ascribed to such term in Section 6231(a)(7) of the Code.

         2.28.   Transfer.  "Transfer" means an assignment, sale, exchange,
gift, pledge, contribution, distribution, disposal, or other transfer.

         2.29.   Unrealized Gain.  "Unrealized Gain" as of any date of
determination means the excess, if any, of the fair value of property (as
determined under Sections 5.1(d) or (e) as of such date of determination) over
the Carrying Value of such property as of such date of determination (prior to
any adjustment to be made pursuant to Sections 5.1(d) or (e) as of such date).

         2.30.   Unrealized Loss.  "Unrealized Loss" as of any date of
determination means the excess, if any, of the Carrying Value of property as of
such date of determination (prior to any adjustment to be made pursuant to
Sections 5.1(d) or (e) as of such date) over the fair value of such property
(as determined under Sections 5.1(d) or (e) as of such date of determination).

                                   SECTION 3

                PARTNERSHIP INTERESTS AND CAPITAL CONTRIBUTIONS

         3.1.    Partnership Interests. The Partnership Interests shall be
expressed in terms of the Partners' Participation Percentages.  Teleglobe
Mobile's Participation Percentage shall be sixty-four point twenty-six percent
(64.26%) and OCC's Participation Percentage shall be thirty-five point
seventy-four percent (35.74%) as of the Restatement Date after giving effect to
the contribution described in Subsection 3.2.2 of the Omnibus Agreement,
subject to adjustments thereafter pursuant to Section 3.4 hereof (such further
adjustments to include, without limitation,





                                      -5-
<PAGE>   10

the adjustment resulting from the contribution described in Subsection 3.5.2 of
the Omnibus Agreement).  The Partners shall be entitled to receive the
distributions set forth in Sections 4 and 10.

         3.2.    Withdrawal of Capital Contributions.  No Partner shall have
the right to withdraw or reduce any part of its capital contributions except as
provided in this Agreement.

         3.3.    Loans.

                 (a)      Optional Loans. The General Partner shall have the
         right to make a loan of cash to the Partnership at any time on such
         terms as the General Partner may determine; provided, however, that in
         no event shall any such optional loan be secured by Partnership
         assets, bear interest or original issue discount or be with recourse
         to any Partner.

                 (b)      Stock Option Plan Loans.  To the extent (i) the
         Partnership has agreed to reimburse OCC for the costs paid by OCC
         pursuant to Section 6.06 of the Orbital Communications Corporation
         1992 Stock Option Plan (including the payment by OCC of withholding
         taxes with respect to the exercise of stock options) in purchasing
         stock acquired by employees or former employees of the Partnership
         (the "Stock Option Plan Costs"), and (ii) the Partnership is permitted
         to reimburse OCC for the Stock Option Plan Costs under the terms of
         the Indenture, the Partnership shall pay to OCC the Stock Option Plan
         Costs including, without limitation, amounts owed under notes payable
         by OCC to former employees of the Partnership."

         3.4.    Additional Capital Contributions. If the Partnership shall
require a capital contribution, the Partnership shall so notify the Partners
and each Partner shall have the opportunity, but not the obligation, to
contribute in cash or immediately available funds an amount equal to such
capital contribution multiplied by such Partner's Participation Percentage.  If
either Partner declines to make a contribution within five (5) Business Days of
the date upon which the Partnership notified the Partners of such requirement
(it being understood that if a Partner has not contributed its share at the
expiration of such five (5) Business Day-period, it will be deemed to have
declined to contribute), then:

                 (a)      The other Partner shall be entitled to contribute the
         amount so declined to be contributed (in addition to any amount such
         Partner is entitled to contribute pursuant to the preceding sentence)
         within five (5) Business Days of the date upon which the other Partner
         declined or was deemed to have declined to contribute its share, and

                 (b)      Based on contributions so made, the Partners'
         Participation Percentages shall be adjusted immediately following the
         expiration of the five (5) Business Day-period referred to in
         subsection (a) above as follows:





                                      -6-
<PAGE>   11
                 (i)      Teleglobe Mobile's Participation Percentage shall be
         adjusted so as to equal the percentage equal to the result of the
         following formula, rounded to the second decimal point:

                           299.354M + (TMAC X 1.75)
            ------------------------------------------------------
            $465.841M + [1.75 X (TMAC  + OAC)] + (OCONV X $33.082M)

            Where:

            M =          million

            TMAC =       the dollar amount expressed in millions rounded to the
                         third decimal point of all contributions made by
                         Teleglobe Mobile from January 1, 2000 to the date of
                         determination of the Partners' Participation
                         Percentages as provided in this Section 3.4(b),
                         excluding the contribution referred to in Subsection
                         3.2.2 of the Omnibus Agreement.

            OAC =        the dollar amount expressed in millions rounded to the
                         third decimal point of all contributions made by OCC
                         from January 1, 2000 to the date of determination of
                         the Partners' Participation Percentages as provided in
                         this Section 3.4(b), excluding the contribution
                         resulting from the conversion referred to in
                         Subsection 3.3.3 of the Omnibus Agreement.

            OCONV =      zero (0) until the conversion referred to in
                         Subsection 3.3.3 of theOmnibus Agreement is effected
                         and one (1) thereafter or, if such conversion is not
                         effected as provided in such Subsection 3.3.3, then
                         zero (0) thereafter.

                 (ii)    OCC's Participation Percentage shall be adjusted so
         as to equal one hundred per cent (100%) minus Teleglobe Mobile's
         Participation Percentage (so adjusted)."


                                   SECTION 4

                                 DISTRIBUTIONS

         4.1.    Distributions. Subject to Sections 4.2, 4.3 and 10.3, the
amount and timing of distributions by the Partnership, either in cash or
property, shall be determined in the discretion of the General Partner,
provided, however, subject to Sections 4.4 and 10.3, that all distributions
(including, without limitation, those made pursuant to Section 4.2) shall be
made to the Partners pro rata in accordance with their respective Participation
Percentages as of the date of distribution and that if the General Partner
determines to effect a distribution both in cash and


                                      -7-
<PAGE>   12

property, equal amounts of such cash and property shall be distributed to the
Partners pro rata in accordance with their respective Participation Percentages
as of the date of distribution.  The Partners confirm that no distributions
under this Section 4.1 occurred prior to January 1, 2000.

         4.2.    Minimum Distribution.  The Partnership shall, not later than
the end of the first quarter of each Partnership Year, make a distribution in
the proportions set forth in Section 4.1 in an amount sufficient to ensure that
each Partner shall have received at least an amount equal to the product of (a)
forty per cent (40%) multiplied by (b) the lesser of (i) such Partner's
distributive share of the Partnership's taxable income (if any) for the
preceding Partnership Year as determined based on the United States Federal
income tax return of the Partnership for such year, or (ii) the excess, if any,
of cumulative Net Income over cumulative Net Loss allocated to such Partner
since the inception of the Partnership.  Notwithstanding the preceding
sentence, except with the approval of the General Partner no distribution shall
be made to a Partner if immediately prior to such distribution there is a zero
or negative balance in any Partner's Capital Account.

         4.3.    Nature of Distributions. The General Partner may determine to
make a distribution in kind or property to the Partners, but such property
shall be distributed in such a fashion as to ensure that the fair value thereof
is distributed and allocated in accordance with Sections 4, 5 and 10 hereof.
For purposes of (a) determining amounts to be distributed to Partners under
Section 4.1, (b) determining Net Income and Net Loss under Section 5, (c)
making adjustments to Capital Accounts under Section 5, and (d) allocations
under Section 5, any property to be distributed in kind shall have the fair
value assigned to such property by the General Partner, subject to the approval
of OCC which shall not be unreasonably withheld or delayed, provided, however,
that such approval shall not be required (a) once OCC's Participation
Percentage falls below 31.67%; or (b) if such fair value is determined by a
major investment banking firm selected by the Partnership which shall not have
rendered financial advisory services to the Partnership, Teleglobe or Orbital
during the preceding year."

         4.4.    Tax Payments.  If the Partnership withholds or pays any tax
(including any addition to tax, penalty, or interest (other than an addition to
tax, penalty, or interest attributable solely to an act or omission of the Tax
Matters Partner)) in respect of any Partner's distributive share of Partnership
income or distributions to any Partner, such payment or withholding shall be
treated as a distribution pursuant to Section 4.1 to such Partner.


                                   SECTION 5

                       PARTNERS' ACCOUNTS; ALLOCATION OF
                        PARTNERSHIP INCOME AND EXPENSES

         5.1.    Maintenance of Capital Accounts.

                 (a)      General Rule.  The Partnership shall maintain for
         each Partner a separate Capital Account in accordance with Section 704
         of the Code and the regulations



                                      -8-
<PAGE>   13

         thereunder ("Capital Account").  If a Partner is both a Limited
         Partner and a General Partner, a single Capital Account shall be
         maintained for such Partner.  Each Partner's Capital Account shall be
         increased by (i) the cash amount or Net Value of all capital
         contributions made by such Partner to the Partnership and (ii) all
         items of Net Income allocated to such Partner and decreased by (A) the
         cash amount or Net Value of all actual and deemed distributions of
         cash or property made to such Partner and (B) all items of Net Loss
         allocated to such Partner.

                 (b)      Computation of Items of Income, Gain, Loss or
         Deduction.  For purposes of computing the amount of any item of
         income, gain, deduction or loss to be reflected in the Partners'
         Capital Accounts, the determination, recognition and classification of
         any such item shall be the same as its determination, recognition and
         classification for United States Federal income tax purposes
         (including any method of depreciation, cost recovery or amortization
         used for this purpose), provided that:

                          (i)     In accordance with the requirements of
                 Section 704(c) of the Code and Treasury Regulations Section
                 1.704-1(b)(2)(iv)(d), any deductions for depreciation, cost
                 recovery or amortization attributable to Contributed Property
                 shall be determined as if the adjusted basis of such property
                 on the date it was acquired by the Partnership was equal to
                 the fair value of such property.  Upon an adjustment pursuant
                 to Section 5.1(d) to the Carrying Value of any Partnership
                 property subject to depreciation, cost recovery or
                 amortization, any further deductions for such depreciation,
                 cost recovery or amortization attributable to such property
                 shall be determined as if the adjusted basis of such property
                 was equal to the Carrying Value of such property immediately
                 following such adjustment.

                          (ii)    Any income, gain or loss attributable to the
                 taxable disposition of any property shall be determined by the
                 Partnership as if the adjusted basis of such property as of
                 such date of disposition was equal in amount to the
                 Partnership's Carrying Value with respect to such property as
                 of such date.

                          (iii)   The computation of all items of income, gain,
                 loss and deduction shall be made, as to those items described
                 in Section 705(a)(1)(B) or Section 705(a)(2)(B) of the Code,
                 without regard to the fact that such items are not includable
                 in gross income or are neither currently deductible nor
                 capitalizable for United States Federal income tax purposes.
                 For this purpose, amounts paid or incurred to organize the
                 Partnership or to promote the sale of interests in the
                 Partnership that are neither deductible nor amortizable under
                 Section 709 of the Code, and deductions for any losses
                 incurred in connection with the sale or exchange of
                 Partnership assets disallowed pursuant to Section 267(a)(1) or
                 Section 707(b) of the Code, shall be treated as expenditures
                 described in Section 705(a)(2)(B) of the Code.


                                      -9-
<PAGE>   14

                 (c)      Transferees.  Generally, a transferee of a Partner's
         Partnership Interest will succeed to the Capital Account relating to
         the interest transferred.  However, if the transfer causes a
         termination of the Partnership under Section 708(b)(1)(B) of the Code,
         the Partnership's properties shall be deemed to have been distributed
         in liquidation of the Partnership to the Partners (including the
         transferee of a Partnership Interest) and deemed recontributed by such
         Partners in reconstitution of the Partnership.  In such event, the
         Carrying Values of the Partnership properties shall be adjusted
         immediately prior to such deemed distribution pursuant to Section
         5.1(e) (and such adjusted Carrying Values shall constitute the Net
         Values of such properties upon this deemed contribution to the
         reconstituted Partnership).  The Capital Accounts of such
         reconstituted Partnership shall be maintained in accordance with the
         principles of this Section 5.1.

                 (d)      Adjustments to Carrying Values. In accordance with
         Treasury Regulations Section 1.704-1(b)(2)(iv)(f), in connection with
         either (i) the contribution of money or other property (other than a
         de minimis amount) to the Partnership by a new or existing Partner in
         consideration for an interest in the Partnership or (ii) a
         distribution of money or other property (other than a de minimis
         amount) by the Partnership to a retiring or continuing Partner as
         consideration for an interest in the Partnership, the Capital Accounts
         of all Partners and the Carrying Values of all Partnership properties
         may be, as determined by the General Partner, adjusted (consistent
         with the provisions hereof) upwards or downwards to reflect any
         Unrealized Gain or Unrealized Loss attributable to each Partnership
         property, as if such Unrealized Gain or Unrealized Loss had been
         recognized upon an actual sale of each such property at such time and
         had been allocated to the Partners pursuant to Section 5.2.  For
         purposes of determining such Unrealized Gain or Unrealized Loss, the
         fair value of Partnership assets shall be determined by the General
         Partner using such reasonable methods of valuation as it in its sole
         discretion deems appropriate, subject to the approval of OCC which
         shall not be unreasonably withheld or delayed, provided, however, that
         such approval shall not be required (i) once OCC's Participation
         Percentage falls below 15%; or (ii) if such fair value is determined
         by a major investment banking firm selected by the Partnership which
         shall not have rendered financial advisory services to the
         Partnership, Teleglobe or Orbital during the preceding year.

         Without limiting the generality of the foregoing and notwithstanding
         any other provision of this Agreement, the proportion that the dollar
         amount of the Capital Account of a Partner bears to the dollar amount
         of the Capital Account of the other Partner shall at all times be
         equivalent to the proportion that the Participation Percentage of such
         Partner bears to the Participation Percentage of such other Partner.
         Accordingly, at any time a discrepancy arises between the respective
         Participation Percentages of the Partners, the General Partner will
         immediately adjust upwards and/or downwards the respective Capital
         Accounts of the Partners as may be required to reflect the provisions
         of the preceding sentence.

                 (e)      Effect of Distributions in Kind on Capital Accounts.
         In accordance with Treasury Regulations Section 1.704-1(b)(2)(iv)(e),
         immediately prior to the actual or





                                      -10-
<PAGE>   15
         deemed distribution of any Partnership property in kind, the Capital
         Accounts of all Partners and the Carrying Value of each such
         Partnership property shall be adjusted (consistent with the provisions
         hereof) upward or downward to reflect any Unrealized Gain or
         Unrealized Loss attributable to such Partnership property as if such
         Unrealized Gain or Unrealized Loss had been recognized upon an actual
         sale of each such property immediately prior to such distribution and
         had been allocated to the Partners, at such time, pursuant to Section
         5.2.  For purposes of determining such Unrealized Gain or Unrealized
         Loss, the fair values of relevant Partnership properties shall be
         determined by the General Partner pursuant to Section 6.4 using such
         reasonable methods of valuation as it in its sole discretion deems
         appropriate.

         5.2.    Allocations of Net Income and Net Loss.

                 (a)      In General.  Subject to Section 5.2(b), Net Income
         and Net Loss shall be allocated to the Capital Accounts as follows:

                          (i)     Subject to Section 5.2(a)(iii), Net Income
                 shall be allocated to the Partners in proportion to their
                 Participation Percentages.

                          (ii)    Subject to Section 5.2(a)(iii), Net Loss
                 shall be allocated to the Partners in proportion to their
                 Participation Percentages.

                          (iii)   To the extent Net Loss allocated to a Partner
                 pursuant to Section 5.2(a)(ii) or this Section 5.2(a)(iii)
                 would, but for this Section 5.2(a)(iii), cause or increase any
                 deficit in the Capital Account maintained with respect to such
                 Partner as of the end of such Partnership Year, such Net Loss
                 shall be reallocated first to the other Partners in proportion
                 to, and to the extent of, their positive Capital Account
                 balances, and then to the General Partner in proportion to its
                 Participation Percentage.  If any Net Loss is or was
                 reallocated pursuant to the preceding sentence (or its
                 counterpart in the Original Agreement), Net Income shall
                 thereafter be allocated so as to offset, to the extent
                 possible, such reallocations of Net Loss.

                 (b)      Special Provisions Governing Capital Account
         Allocations.  To the extent inconsistent with the provisions of
         Section 5.2(a) the following special provisions shall govern
         allocations to Capital Accounts:

                          (i)     If there is a net decrease in "partnership
                 minimum gain" (within the meaning of Treasury Regulations
                 Section 1.704-2(b)(2)) during a taxable year, each Partner
                 shall (subject to the exceptions set forth in Treasury
                 Regulations Section 1.704-2(f)) be allocated items of income
                 and gain for such year (and, if necessary, for subsequent
                 years) equal to the portion of such Partner's share of the net
                 decrease in partnership minimum gain.  This Section 5.2(b)(i)
                 is intended to be a "minimum gain chargeback" within meaning
                 of Treasury Regulations





                                      -11-
<PAGE>   16


                 Section 1.704-2(f), and is to be interpreted to comply with
                 the requirements of such regulation.

                      (ii)        If any Partner unexpectedly receives any
                 adjustments, allocations or distributions described in
                 Treasury Regulations Section 1.704-1(b)(2)(ii)(d)(4),
                 1.704-1(b)(2)(ii)(d)(5), or 1.704-1(b)(2)(ii)(d)(6), items of
                 income and gain shall be specially allocated to such Partner
                 in an amount and manner sufficient to eliminate a deficit in
                 its Capital Account (after taking into account adjustments,
                 distributions and allocations described in Treasury
                 Regulations Section 1.704-1(b)(2)(ii)(d)(4), (5) and (6)) in
                 excess of its obligations to restore such deficit (within the
                 meaning of Treasury Regulations Section 1.704-1(b)(2)(ii)(d))
                 created by such adjustments, allocations or distributions as
                 quickly as possible.  This Section 5.2(b)(ii) is intended to
                 constitute a "qualified income offset" within the meaning of
                 Treasury Regulations Section 1.704-1(b)(2)(ii)(d)(3) and is to
                 be interpreted to comply with the requirements of such
                 regulation.

                      (iii)       The interest of the General Partner as
                 general partner, including the interests of any additional or
                 substituted general partner, taken together, in each material
                 item of Partnership income, gain, loss, deduction or credit
                 shall be equal to at least one percent (1%) of each such item
                 at all times during the existence of the Partnership.

                      (iv)       In accordance with Treasury Regulations
                 Section 1.704-2,

                                 (A)       any items of partnership loss,
                          deduction or expenditure (including expenditures
                          described in Section 705(a)(2)(B) of the Code) that
                          are attributable to liabilities of the Partnership
                          for which no Partner bears the economic risk of loss
                          shall be allocated in the same manner as Net Losses
                          hereunder, and

                                 (B)       any items of partnership loss,
                          deduction or expenditure (including expenditures
                          described in Section 705(a)(2)(B) of the Code) that
                          are attributable to nonrecourse debt of the
                          Partnership for which one or more Partners bears the
                          economic risk of loss shall be allocated to each
                          Partner in proportion to the extent to which such
                          Partner bears such economic risk of loss.

                          (v)    Any special allocations of items of income or
                 gain pursuant to Sections 5.2(b)(i), (ii), (iii) and (iv)
                 shall be taken into account in computing subsequent
                 allocations of items of income, gain, deduction or loss so
                 that the net amounts of any items so allocated shall, to the
                 extent possible and consistent with such Sections, be equal to
                 the net amounts that would have been allocated to each Partner
                 had the allocations made pursuant to such Sections not been
                 made.

                 (c)      Allocations for Tax Purposes.






                                      -12-
<PAGE>   17


                      (i)         For United States Federal income tax
                 purposes, except as otherwise provided in this Section 5.2(c),
                 each item of income, gain, loss, and deduction of the
                 Partnership shall be allocated among the Partners in the same
                 proportions as items comprising Net Income or Net Loss, as the
                 case may be, are allocated among the Partners.  Credits shall
                 be allocated as provided in Treasury Regulations Section
                 1.704-1(b)(4)(ii).

                      (ii)        In the case of Contributed Property, items of
                 income, gain, loss, depreciation, amortization and cost
                 recovery shall be allocated among the Partners in a manner
                 consistent with the principles of Section 704(c) of the Code.
                 In the case of Adjusted Property, items of income, gain, loss,
                 depreciation and cost recovery deductions attributable thereto
                 shall (A) first, be allocated among the Partners in a manner
                 consistent with the principles of Section 704(c) of the Code
                 to take into account the Unrealized Gain or Unrealized Loss
                 attributable to such property and the allocation thereof
                 pursuant to Section 5.1(c) or 5.1(d), and (B) second, in the
                 event such property was originally Contributed Property, be
                 allocated among the Partners in a manner consistent with
                 subsection (ii) above.

                      (iii)       To the extent permissible under applicable
                 Treasury Regulations, the amount of any gain from a
                 disposition allocated to (or recognized by) a Partner (or its
                 successor in interest) for United States Federal income tax
                 purposes pursuant to the above provisions shall be deemed to
                 be Recapture Income to the extent such Partner has been
                 allocated any deduction or credit directly or indirectly
                 giving rise to the treatment of such gain as Recapture Income.

                      (iv)        All items of income, gain, loss, deduction
                 and credit recognized by the Partnership for United States
                 Federal income tax purposes and allocated to the Partners in
                 accordance with the provisions hereof shall be determined
                 without regard to any adjustment made pursuant to Section 743
                 of the Code; provided, however, that such allocations, once
                 made, shall be adjusted as necessary or appropriate to take
                 into account those adjustments permitted by Section 743 of the
                 Code, and any adjustments made pursuant to Section 734 of the
                 Code shall be allocated to the extent permitted under and in
                 accordance with the rules of Treasury Regulations Section
                 1.704-1(b)(2)(iv)(m).

                 (d)  Other Rules Pertaining to Allocations.  Subject to
         Section 6.2(g), the Tax Matters Partner may adopt and employ such
         methods and procedures for (i) the determination and allocation of
         adjustments under Sections 704(c), 734 and 743 of the Code, (ii) the
         provision of tax information and reports to Partners, (iii) the
         adoption of reasonable conventions and methods for the valuation of
         assets and the determination of tax basis, (iv) the allocation of
         asset values and tax basis, and (v) conventions for the determination
         of cost recovery, depreciation and amortization deductions and the
         maintenance of inventories, as it determines in its sole discretion
         are necessary and appropriate to execute the provisions of this
         Agreement, and to comply with United






                                      -13-
<PAGE>   18


         States Federal and state tax laws.  To the fullest extent permitted by
         law, the Tax Matters Partner shall be indemnified and held harmless by
         the Partnership for any expenses, penalties or other liabilities
         arising as a result of decisions made in good faith on any of the
         matters referred to in the preceding sentence.


                                   SECTION 6

                                   MANAGEMENT

         6.1.    Authority of General Partner.  Except to the extent required
by law or specific provisions of this Agreement, the management of the
Partnership and all Partnership affairs shall be the exclusive responsibility
of the General Partner.  Without limiting the generality of the foregoing,
subject to Sections 6.2, 6.3, 6.4 and 6.5 hereof, the General Partner is
authorized on behalf of the Partnership, without the consent of any other
Partner, to:

                 (a)      expend the capital and revenues of the Partnership in
         furtherance of the Partnership's business and pay, in accordance with
         the provisions of this Agreement, all expenses, debts and obligations
         of the Partnership to the extent that funds of the Partnership are
         available therefor;

                 (b)      invest and reinvest the Partnership's funds;

                 (c)      enter into, amend or terminate agreements (including
         without limitation partnership agreements) and contracts with any
         Person or Persons, institute, defend and settle litigation arising
         therefrom, and give receipts, releases and discharges with respect to
         all of the foregoing and any matters incident thereto;

                 (d)      maintain, at the expense of the Partnership, adequate
         records and accounts of all operations and expenditures and furnish
         the Partners with the reports referred to in Section 8;

                 (e)      purchase, at the expense of the Partnership,
         liability, casualty, fire and other insurance and bonds to protect the
         Partnership's properties, business, partners and employees, the
         General Partner, its stockholders and its respective directors,
         officers and employees;

                 (f)      borrow for working capital and, in connection
         therewith, issue notes, debentures and other debt securities and
         mortgage, pledge, encumber or hypothecate the assets of the
         Partnership, to secure repayment of such borrowed sums;

                 (g)      obtain replacement of any mortgage, encumbrance,
         pledge, hypothecation or other security device and prepay, in whole or
         in part, modify, consolidate or extend any such mortgage, encumbrance,
         pledge, hypothecation or other security device, subject to the
         limitations contained in this Agreement;



                                      -14-
<PAGE>   19

                 (h)      sell, lease, trade, exchange or otherwise dispose of
         all or any portion of the property of the Partnership subject to the
         limitations contained in this Agreement;

                 (i)      employ, at the expense of the Partnership,
         consultants, accountants, attorneys, brokers, engineers, escrow agents
         and others and terminate such employment;

                 (j)      execute and deliver any and all instruments necessary
         or incidental to the conduct of the business of the Partnership;

                 (k)      determine the amount, timing and character of
         distributions to Partners pursuant to Sections 4.1 and 4.3;

                 (l)      appoint or remove officers to the Partnership;

                 (m)      act on behalf of the Partnership with respect to the
         obligations of the Partnership under any of the Definitive Agreements;
         and

                 (n)      do such other things and engage in such other
         activities related to the foregoing as may be necessary, convenient or
         advisable with respect to the conduct of the business of the
         Partnership, and have and exercise all of the powers and rights
         conferred upon limited partnerships formed under the Delaware Act.

         By executing this Agreement, each Partner shall be deemed to have
consented to any exercise by the General Partner of any of the foregoing
powers.

         6.2.    OCC Approval.  The approval of OCC shall be required to:

                 (a)      enter into any transaction (excluding the Definitive
         Agreements) with an Affiliate of the General Partner;

                 (b)      make on behalf of the Partnership an assignment for
         the benefit of creditors, decide on behalf of the Partnership to
         subject the Partnership to any proceedings under any bankruptcy or
         insolvency law, decide to avail the Partnership of the benefit of any
         other legislation for the benefit of debtors, or take steps to wind up
         or terminate the Partnership existence; and

                 (c)      amend this Section 6.2.

         This Section 6.2 shall no longer apply and it shall be deemed deleted
         once OCC's Participation Percentage falls below 15%.

         6.3.    OCC Approval.  The approval of OCC shall be required to amend,
in a manner detrimental to OCC, the provisions of Sections 3, 4, 5, 6.3 and 10
of this Agreement, it being understood that any amendment to any such Sections
upon the admission of another Limited





                                      -15-
<PAGE>   20

Partner that is not an Affiliate of the General Partner shall not be deemed to
be detrimental to OCC if all Limited Partners are treated substantially equally
in connection with such amendment.

         6.4.    OCC Approval.  Subject to the terms hereof, the approval of
OCC shall be required to:

                 (a)      transfer all or substantially all the assets of the
         Partnership or contract to do so;

                 (b)      merge or consolidate the Partnership with any other
         Person; provided, however, that this subsection (b) shall not be
         applicable in the event such merger or consolidation is deemed fair
         from a financial point of view to the Partnership in the written
         opinion of a major investment banking firm selected by the Partnership
         which shall not have rendered financial advisory services to the
         Partnership, Teleglobe or Orbital during the preceding year;

                 (c)      permit the entry by the Partnership into any
         additional lines of business other than those described in Section
         1.3, as contemplated in the Omnibus Agreement or directly related
         thereto;

                 (d)      select or remove the independent certified public
         accountant for the Partnership pursuant to Section 8.4 or adopt, or
         modify in any material respect, any significant accounting policy or
         tax policy;

                 (e)      determine the value of the Partnership for purposes
         of Article X of the Master Agreement; and

                 (f)      amend any provision of this Agreement; provided,
         however, that notwithstanding any other provision of this Agreement,
         no Partner shall delay, frustrate or otherwise interfere with in any
         way the raising of debt or equityfinancing by the Partnership from any
         Person not currently admitted to the Partnership which financing has
         been initiated or approved by the General Partner (it being understood
         that the simultaneous raising of debt or equity financing by OCC or
         Teleglobe Mobile shall be deemed for the purposes hereof to interfere
         with the raising of debt or equity financing by the Partnership);
         provided that in the case of any such equity financing, the
         consideration expected to be received by the Partnership from such
         financing shall be fair to the Partnership as determined by the
         General Partner; and provided further that in the case of any such
         equity financing (executed in one transaction or a series of
         transactions) which is intended to result in the admission to the
         Partnership of a Person or Persons who following such financing would
         hold a Participation Percentage or Participation Percentages equal to
         or greater than twenty-five percent (25%), the consideration expected
         to be received by the Partnership from such financing shall be fair to
         the Partnership, in the written opinion of a major investment banking
         firm selected by the Partnership which shall not have rendered
         financial advisory services to the Partnership, Teleglobe or Orbital
         during the preceding year.



                                      -16-
<PAGE>   21

         This Section 6.4 shall no longer apply and it shall be deemed deleted
         once OCC's Participation Percentage falls below 31.67%; provided,
         however, that should OCC's Participation Percentage return to 31.67%
         or higher after having fallen below 31.67% solely as a result of the
         conversion referred to in Subsection 3.3.3 of the Omnibus Agreement,
         then this Section 6.4 will apply again until OCC's Participation
         Percentage thereafter falls below 31.67%, at which time this Section
         6.4 shall no longer apply and it shall be deemed deleted.

         6.5.    Meetings.  Meetings of the Partners may be called by the
General Partner and shall be held at the principal offices of the Partnership
or at such other location as shall be reasonably determined by the General
Partner.  Except as otherwise specified in Section 8.5 hereof, the General
Partner shall have no obligation to call a meeting of the Partners at any time.
Notwithstanding any provision of applicable law, not less than forty-eight (48)
hours prior written notice of the time, place and purpose of each meeting of
the Partners shall be provided to each Partner, provided that any Partner may
waive compliance with such notice requirement.  Any meeting may be adjourned
from time to time by the General Partner, and the meeting may be held as
adjourned without further notice.  Any one or more Partners may participate in
any meeting by means of conference telephone, video or similar communications
equipment allowing all persons participating in the meeting to hear each other
at the same time.  Participation by Partners in a meeting held by means of a
conference telephone, video or similar communications equipment shall
constitute presence in person at a meeting.  Any action required or permitted
to be taken with the approval of one or more Partners may be taken without a
meeting upon the written consent of such Partners, which written consent shall
be filed with the records of the meetings of the Partners.

         6.6.    Representation at Meetings; Reimbursement. The General Partner
shall be represented at meetings of the Partners by up to three authorized
officers or other authorized agents, it being the expectation of the General
Partner that it will select three representatives who will use reasonable
efforts to attend each meeting of the Partners.  At each meeting of the
Partners, one representative of the General Partner shall be entitled to vote
such Partner's Participation Percentage. The General Partner shall be entitled
to reimbursement of the reasonable out-of-pocket expenses incurred by it or its
representatives in attending meetings of the Partners.  No amount so paid to
any such member shall be deemed to be a distribution of Partnership assets for
purposes of this Agreement or the Delaware Act.  Except for the reimbursement
of expenses as provided in this Section 6.6, the General Partner or
representatives thereof shall not receive any compensation for its, his or her
services as such.

         In addition, so long as OCC's Participation Percentage is not less
than fifteen percent (15%), then at each meeting of the Partners, two
representatives of OCC as well as the Chief Executive Officer of ORBCOMM shall
be entitled to be present as observers and OCC shall be entitled to
reimbursement of expenses to the extent set forth for the General Partner
herein with respect to its two representatives, except for travel expenses.

         6.7.    Designation of Officers.  Officers of the Partnership shall be
nominated by the President of the Partnership and elected by the General
Partner and shall exercise such authority




                                      -17-
<PAGE>   22

as they are granted by the General Partner.  If an officer is an employee of
the General Partner, the Partnership will promptly reimburse the General
Partner the pro rata share of expenses, including compensation and overhead,
attributable to such officer of the Partnership by reference to the share of
his or her total time spent upon Partnership operations.  Without limiting the
foregoing, the General Partner shall, no later than promptly following the
Restatement Date, appoint one or more officers to have such authority as the
General Partner determines to be appropriate to act for the Partnership with
respect to the Procurement Contract after the Restatement Date.

         6.8.    Removal of Officers.  Any officer of the Partnership may be
removed at any time and for any reason by approval or written consent of the
General Partner.  Any officer removed pursuant to this Section shall remain
entitled to exculpation and indemnification from the Partnership pursuant to
Section 7.3 with respect to any matter arising prior to his or her removal.


                                   SECTION 7

                    AGREEMENTS AND AUTHORITY OF THE PARTNERS

         7.1.    Rights and Duties of Limited Partners.

                 (a)      Except as otherwise specifically provided in this
         Agreement, the Limited Partners in their capacities as such shall not
         participate in the control, management, direction or operation of the
         business or affairs of the Partnership and shall have no power to act
         for or bind the Partnership.

                 (b)      Pursuant to Delaware law (and provided that such
         Limited Partner does not, in addition to the exercise of its rights
         and powers as a Limited Partner, take part in the control of the
         business of the Partnership), no Limited Partner shall be liable for
         losses or debts of the Partnership in its capacity as a Limited
         Partner beyond the aggregate amount of its capital contributions,
         except that (i) when a Limited Partner has received a return of any
         part of its capital contribution without violation of this Agreement
         or the Delaware Act it shall be liable to the Partnership for one year
         thereafter for the amount of the returned contribution, but only to
         the extent necessary to discharge the Partnership's liabilities to
         creditors who extended credit to the Partnership during the period the
         capital contribution was held by the Partnership, and (ii) if the
         Limited Partner has received the return of any part of its capital
         contribution in violation of this Agreement or the Delaware Act, it is
         liable to the Partnership for a period of six years thereafter for the
         amount of such contribution wrongfully returned to it; provided,
         however, that to the extent any Limited Partner repays to the
         Partnership pursuant to the foregoing provision a greater percentage
         of the distributions made to it than any or all other Limited Partners
         similarly liable to the Partnership, such Limited Partner shall have a
         right of contribution from each such other Limited Partner to the
         extent that such other Limited Partner has repaid pursuant to such
         provision a lesser percentage of the distributions made to it.





                                      -18-
<PAGE>   23


         7.2.    Restrictions on General Partner's Authority; Loss Sharing.

                 (a)  The General Partner may, without the approval or
         written consent to the specific act by all of the Partners given in
         this Agreement or by other written instrument executed and delivered
         by the Partners subsequent to the date of this Agreement, do any of
         the following:

                      (i)         any act in contravention of this Agreement or
                 the Certificate;

                      (ii)        any act which would make it impossible to
                 carry on the ordinary business of the Partnership, except as
                 otherwise provided in this Agreement; or

                      (iii)       assign any rights in specific Partnership
                 property, for other than a Partnership purpose.

                 (b)  The General Partner shall share responsibility for
         all obligations and losses of the Partnership in excess of the
         Partners' aggregate capital contributions in proportion to their
         Participation Percentages.

         7.3.    Exculpation. The General Partner, and any of its officers,
directors, partners, employees or agents, including any Person who formerly
served in any of the foregoing capacities (each, an "Indemnified Party"), shall
not be liable, in damages or otherwise, to the Partnership or to any of the
Limited Partners for any act or omission by such Indemnified Party pursuant to
the authority granted by this Agreement except if such act or omission results
from gross negligence, willful or wanton misconduct or bad faith of such
Indemnified Party.  The Partnership shall indemnify, defend and hold harmless
each Indemnified Party from and against any and all claims or liabilities of
any nature whatsoever, including reasonable attorneys' fees, arising out of or
in connection with any action taken or omitted by the General Partner or the
officers of the Partnership pursuant to the authority granted by this
Agreement, except where attributable to the gross negligence, willful or wanton
misconduct or bad faith of such Indemnified Party.  An Indemnified Party shall
be entitled to rely on the advice of counsel, public accountants or other
independent experts experienced in the matter at issue, and any act or omission
of such Person pursuant to such advice shall in no event subject such
Indemnified Party to liability to the Partnership or any Partner.

         7.4.    Other Activities.  Subject to the Proprietary Information and
Non-Competition Agreement among Orbital, OCC, Teleglobe, Teleglobe Mobile, the
Partnership, ORBCOMM USA, and ORBCOMM International, any Partner may engage in
or possess an interest in other business venture of any nature or description,
independently or with others, whether presently existing or hereafter created,
including the development, operation and commercial exploitation of aerospace
technology and communications systems, and neither the Partnership nor any
Partner shall have any rights in or to such independent ventures or the income
or profits derived therefrom.




                                      -19-
<PAGE>   24

                                   SECTION 8

                                    ACCOUNTS

         8.1.    Books.  Each Partner shall have the right to inspect the
Partnership's books and records (including a list of the names and addresses of
Partners) at any reasonable time upon advance written request to the General
Partner, which books and records shall be maintained by the Partnership.

         8.2.    Partners' Accounts.  Separate Capital Accounts shall be
maintained for each Partner in accordance with the provisions of Section 5.

         8.3.    Certificates, Reports, Returns and Audits.

                 (a)     The books of account shall be closed promptly after
         the end of each Partnership Year.  Within twenty (20) days of the end
         of the Partnership Year, the General Partner shall provide each Person
         who was a Partner at any time during such Partnership Year an
         unaudited statement of profit and loss for such year.  Within sixty
         (60) days of the end of the Partnership Year, a written report shall
         be made to each Person who was a Partner at any time during such
         Partnership Year that shall include a statement of profit and loss and
         a statement of cash flows for the year then ended, a balance sheet as
         of the close of the Partnership Year and a statement of such Partner's
         Capital Account, all of which shall be prepared in accordance with
         generally accepted accounting principles in the United States, and
         shall be audited by the Partnership's independent public accountants.
         The annual report shall also contain such additional statements with
         respect to the status of the Partnership's business, transactions by
         the Partnership with any of the Partners or any of their Affiliates
         and the distribution of Partnership funds as are considered necessary
         by the General Partner to advise all Partners properly about their
         investment in the Partnership.  With the sole exception of the
         mathematical errors in computation, the annual report and the
         information contained therein shall be deemed conclusive and binding
         upon each Partner unless written objection shall be lodged with the
         General Partner within ninety (90) days after the giving of such
         reports to such Partner.

                 (b)     Within twenty (20) days after the close of each month
         of the Partnership Year other than the final month of the Year,
         commencing with the month of July, 1993, a written report shall be
         made to each Person who was a Partner during the month then ended that
         shall include details with respect to the Partnership's business and
         unaudited financial statements and other relevant information
         regarding the Partnership and its activities during the month,
         including statements with respect to any transactions by the
         Partnership with any of the Partners or any of their respective
         Affiliates and the distribution of Partnership funds as are considered
         necessary by the General Partner to advise all Partners properly about
         their investment in the Partnership.  All such monthly reports shall
         be prepared in accordance with generally accepted accounting
         principles in





                                      -20-
<PAGE>   25
         the United States, using Teleglobe Mobile financial formats, which
         formats shall be approved by OCC, such approval not to be unreasonably
         withheld or delayed.

                  (c)     Teleglobe Mobile shall be the Tax Matters Partner of
         the Partnership.  The Tax Matters Partner shall prepare or cause to be
         prepared all United States, state, local and foreign tax returns of
         the Partnership for each year for which such returns are required to
         be filed.  The Partnership shall reimburse the Tax Matters Partner for
         all expenses incurred by the Tax Matters Partner in carrying out its
         responsibilities as such under the terms of this Agreement, other than
         expenses that attributable to the gross negligence, willful or wanton
         conduct or bad faith of the Tax Matters Partner.

                 (d)      The General Partner shall be obligated to forward a
         copy of this Agreement as filed, or any amendments hereto, to the
         General Partner and only to such Limited Partners as expressly request
         a copy in writing.

         8.4.    Auditors.  For purposes of financial reporting and Federal
income tax return preparation, the independent certified public accounting firm
for the Partnership initially shall be Arthur Andersen; provided, however, that
so long as the Participation Percentage of Teleglobe Mobile is at least fifteen
percent (15%), the audit and tax partners from such independent certified
public accounting firm responsible for the Partnership shall be chosen by
Teleglobe Mobile.

         8.5.    Review Policies. So long as OCC's Participation Percentage is
not less than fifteen percent (15%), the financial performance and business of
the Partnership shall be reviewed at least quarterly by the General Partner at
a meeting of the Partners.

                                   SECTION 9

                TRANSFERS OF PARTNERSHIP INTERESTS; WITHDRAWALS

         9.1.    Transfer of Partnership Interests.  No Partner shall be
permitted, without the consent of the General Partner (which may be withheld in
the General Partner's absolute discretion) (i) to substitute any other Person
for itself as a General or Limited Partner, (ii) to Transfer all or any portion
of its Partnership Interest, (iii) to assign its obligations as a General or
Limited Partner or (iv) to withdraw from the Partnership.

         9.2.    Prohibited Transfers Void.  Any purported Transfer of all or
any portion of a Partner's Partnership Interest that is not in compliance with
Section 9.1 is hereby declared to be null and void and of no force or effect
whatsoever.

         9.3.    Withdrawal of Partners.  If any Partner withdraws or resigns
from the Partnership in violation of this Agreement, the total amount that such
Partner may then or thereafter be required to contribute to the Partnership
pursuant to this Agreement or the Master Agreement





                                      -21-
<PAGE>   26


shall become immediately due and payable and such Partner shall not be entitled
to any further distributions from the Partnership.


                                   SECTION 10

                                  DISSOLUTION

         10.1.   Events of Dissolution.  The Partnership shall continue until
11:59 p.m. on December 31, 2013, unless sooner dissolved upon the earliest to
occur of the following events:

                 (a)      removal, withdrawal, resignation, liquidation or
         Bankruptcy (or death, in the case of an individual) (an "Event of
         Withdrawal") of the last remaining General Partner unless a new
         General Partner is appointed within ninety (90) days with the
         unanimous consent of the remaining Partners; or

                 (b)      at any time, with the written consent of the General
         Partner.

         10.2.   Final Accounting.  Upon the dissolution of the Partnership,
the Partnership shall prepare an accounting of such dissolution, which
accounting shall be audited by the Partnership's independent public accountants
from the date of the last previous accounting to the date of dissolution.

         10.3.   Liquidation.  Upon the dissolution of the Partnership, the
General Partner, or, in the case of an Event of Withdrawal of the last
remaining General Partner, one of the Limited Partners elected by a majority
vote of the Limited Partners, shall act as liquidator to wind up the
Partnership.  The liquidator shall have full power and authority to sell,
assign and encumber any or all of the Partnership's assets and to wind up and
liquidate the affairs of the Partnership in an orderly and business-like
manner. All proceeds from liquidation shall be distributed in the following
order of priority: (a) to the payment of the debts and liabilities of the
Partnership and expenses of liquidation; (b) to the setting up of such reserves
as the liquidator may reasonably deem necessary for any contingent liability of
the Partnership; and (c) the balance to the Partners pro rata in accordance to
their respective Participation Percentages.

         10.4.   Distribution in Kind.  If the liquidate shall determine that a
portion of the Partnership's assets should be distributed in kind to the
Partners, the liquidate shall obtain an independent appraisal of the fair value
of each such asset as of a date reasonably close to the date of liquidation.

         10.5.   Cancellation of Certificate.  Upon the completion of the
distribution of Partnership assets as provided in Section 10.3 and 10.4, the
Partnership shall be terminated and the Person acting as liquidate shall cause
the cancellation of the Certificate and shall take such other actions as may be
appropriate to terminate the Partnership.





                                      -22-
<PAGE>   27

                                   SECTION 11

                                    NOTICES

         11.1.   Method of Notices.  All notices, requests and other
communications to any party hereunder shall be in writing (including any
facsimile transmission or similar writing), and shall be sent either by
telecopier or delivered in person by reputable overnight courier addressed as
follows: if to OCC, to Orbital Communication Corporations, 21700 Atlantic
Boulevard, Dulles, Virginia  20166, Attention: President; if to Teleglobe
Mobile, to it, c/o Teleglobe Inc., 1000, rue de La Gauchetiere ouest, Montreal,
Quebec, Canada H3B 4X5, Attention: Vice President, Chief Legal Officer and
Corporate Secretary (except that any Partner may from time to time give notice
changing its address for this purpose).  Each such notice, request or other
communication shall be effective (a) if given by telecopy, when such telecopy
is transmitted to the telecopy number specified in this Section and the
appropriate answerback is received, (b) if given by reputable overnight
courier, one (1) business day after being delivered to such courier, or (c) if
given by any other means, when received at the address specified in this
Section.

         11.2.   Routine Communications.  Notwithstanding the provisions of
Section 11.1, routine communications such as distribution checks or financial
statements of the Partnership (but not the notice of any meeting required to be
delivered pursuant to Section 6.4) may be sent by first-class mail, postage
prepaid.

         11.3.   Computation of Time.  Except as may be otherwise provided
under the Delaware Act, in computing any period of time under this Agreement,
the day of the act, event or default from which the designated period of time
begins to run shall not be included.  The last day of the period so computed
shall be included, unless it is a Saturday, Sunday or legal holiday, in which
event the period shall run until the end of the next day which is not a
Saturday, Sunday or legal holiday.


                                   SECTION 12

                               GENERAL PROVISIONS

         12.1.   Entire Agreement.  This Agreement, together with each of the
Definitive Agreements, constitutes the entire agreement among the parties with
respect to the subject matter hereof and supersedes any prior agreement or
understanding among the parties with respect to the subject matter hereof.

         12.2.   Amendment; Waiver.  Except as provided otherwise herein, this
Agreement may not be amended nor may any rights hereunder be waived except by
an instrument in writing signed by the parties.







                                      -23-
<PAGE>   28

         12.3.   Governing Law.  This Agreement shall be construed in
accordance with and governed by the laws of the State of Delaware, without
giving effect to the provisions, policies or principles thereof relating to
choice or conflict of laws.

         12.4.   Binding Effect.  Except as provided otherwise herein, this
Agreement shall be binding upon and shall inure to the benefit of the parties
and their respective successors and permitted assigns.

         12.5.   Counterparts.  This Agreement may be executed in any number of
counterparts of the signature pages, each of which shall be considered an
original, but all of which together shall constitute one and the same
instrument.

         12.6.   Separability.  Any provision of this Agreement that is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining portions hereof or affecting the validity or
enforceability of such provision in any other jurisdiction.

         12.7.   Headings.  The section and other headings contained in this
Agreement are for reference purposes only and shall not affect the meaning or
interpretation of this Agreement.

         12.8.   Gender and Number.  Whenever required by the context hereof,
the singular shall include the plural and the plural shall include the
singular.  The masculine gender shall include the feminine and neuter genders,
and the neuter gender shall include the masculine and feminine genders.

         12.9.   Waiver of Partition and Dissolution.  Each Partner hereby
irrevocably waives, during the term of the Partnership, any right that it may
have to maintain any actions (a) for partition with respect to any Partnership
property, and (b) for dissolution of the Partnership except upon any of the
events described in Section 10.

         12.10.  Coordination with Master Agreement.  The provisions of this
Agreement shall be subject to the provisions of the Master Agreement.  If there
is a conflict between this Agreement and the Master Agreement, the provisions
of the Master Agreement shall control.

         12.11.  Dispute Resolution.  Any controversy or claim that may arise
under, out of, in connection with or relating to this Agreement shall be
resolved in accordance with Section 13.4 of the Master Agreement.

    [remainder of page intentionally left blank - signature page to follow]






                                      -24-
<PAGE>   29

         IN WITNESS WHEREOF the parties hereto have executed this Agreement as
of the day and year first above written.


                                    TELEGLOBE MOBILE PARTNERS

                                    By:  Teleglobe Mobile Investment Inc.,
                                         its Managing Partner


                                    By:
                                       -----------------------------------------
                                    Name: Andre Bourbonnais
                                    Title: President


                                    ORBITAL COMMUNICATIONS CORPORATION



                                    By:
                                       -----------------------------------------
                                    Name:
                                    Title:


                                      -25-


<PAGE>   1
                                                                   Exhibit 10.1

OMNIBUS AGREEMENT entered into as of the 1st day of January, 2000

BY AND AMONG:               ORBITAL SCIENCES CORPORATION, a corporation
                            governed by the laws of Delaware ("ORBITAL");

AND:                        ORBITAL COMMUNICATIONS CORPORATION, a corporation
                            governed by the laws of Delaware ("OCC") owned
                            98.65% by Orbital;

AND:                        TELEGLOBE INC., a corporation governed by the laws
                            of Canada ("TELEGLOBE");

AND:                        TELEGLOBE MOBILE PARTNERS, a Delaware general
                            partnership ("TELEGLOBE MOBILE") indirectly owned
                            100% by Teleglobe;

AND:                        ORBCOMM GLOBAL, L.P., a Delaware limited partnership
                            ("ORBCOMM") owned by OCC and Teleglobe Mobile;

                            (OCC and Teleglobe Mobile are collectively referred
                            to herein as the "PARTNERS", and Orbital, Teleglobe,
                            the Partners, and ORBCOMM are collectively referred
                            to herein as the "PARTIES")


ORBCOMM

WHEREAS ORBCOMM was organized by the filing on June 30, 1993 of a Certificate of
Limited Partnership with the Secretary of State of the State of Delaware;

WHEREAS the Partners, Orbital, and Teleglobe have executed a Restated Master
Agreement dated as of September 12, 1995, as amended as of February 5, 1997 (the
"MASTER AGREEMENT");

WHEREAS the Partners have executed, both as general and limited partners, a
Restated Agreement of Limited Partnership of ORBCOMM Global, L.P. dated as of
September 12, 1995, as amended as of December 2, 1996 (the "PARTNERSHIP
AGREEMENT");


<PAGE>   2


MARKETING PARTNERSHIPS

WHEREAS each of ORBCOMM USA, L.P. ("ORBCOMM USA") and ORBCOMM International
Partners, L.P. ("ORBCOMM INTERNATIONAL") was organized by the filing on June 30,
1993 of a Certificate of Limited Partnership with the Secretary of State of the
State of Delaware;

WHEREAS ORBCOMM and OCC have executed, both as general and limited partners, a
Restated Agreement of Limited Partnership of ORBCOMM USA, L.P. dated as of
September 12, 1995 (the "USA PARTNERSHIP AGREEMENT"), and ORBCOMM and Teleglobe
Mobile have executed, both as general and limited partners, a Restated Agreement
of Limited Partnership of ORBCOMM International Partners, L.P. dated as of
September 12, 1995 (the "INTERNATIONAL PARTNERSHIP AGREEMENT");

WHEREAS OCC and ORBCOMM USA have executed a Restated System Charge Agreement
dated as of September 12, 1995 (the "USA SYSTEM CHARGE AGREEMENT"), and
Teleglobe Mobile, ORBCOMM and ORBCOMM International have executed a Restated
International System Charge Agreement dated as of September 12, 1995 (the
"INTERNATIONAL SYSTEM CHARGE AGREEMENT") (the USA System Charge Agreement and
the International System Charge Agreement are collectively referred to herein as
the "SYSTEM CHARGE Agreements");

OTHER ENTITIES

WHEREAS Orbital was engaged in, and holds title to assets relating to, the
business of, among other things, developing, designing, manufacturing, marketing
and selling to commercial customers automated tracking and cargo status data
systems of unpowered mobile assets such as truck trailers, railcars and
containers (the "GEMTRAK BUSINESS");

WHEREAS Teleglobe owns 3,600 Class A voting shares in the share capital of
ORBCOMM Canada Inc., a Canadian corporation ("ORBCOMM CANADA") representing
ninety-two point five percent (92.5%) of the issued and outstanding voting
shares in the share capital of ORBCOMM Canada;

OTHER AGREEMENTS AND LICENSES

WHEREAS ORBCOMM and Orbital have executed an ORBCOMM System Procurement
Agreement dated as of September 12, 1995, as amended (the "1995 PROCUREMENT
AGREEMENT") and an ORBCOMM Procurement Agreement dated as of February 1, 1999,
as amended (the "1999 PROCUREMENT AGREEMENT") (the 1995 Procurement Agreement
and the 1999 Procurement Agreement are collectively referred to herein as the
"PROCUREMENT AGREEMENTS");

WHEREAS the Federal Communications Commission (the "FCC") granted various
licenses to OCC for the construction, launch and operation of a total of 48
low-earth orbit satellites to


                                       2
<PAGE>   3


provide two-way data and messaging communications and position determination
services, and for the operation of four gateway Earth stations and the
deployment of up to 200,000 subscriber units in the continental United States
(the "FCC LICENSES");

WHEREAS ORBCOMM and Orbital have executed an Amended and Restated Administrative
Services Agreement dated as of January 1, 1997 (the "ADMINISTRATIVE SERVICES
AGREEMENT");

PURPOSE

WHEREAS, the Parties wish to amend certain agreements with respect to ORBCOMM
and conclude certain other transactions described herein;

NOW, THEREFORE, IN CONSIDERATION OF THE FOREGOING AND THE RESPECTIVE
REPRESENTATIONS, WARRANTIES, COVENANTS AND AGREEMENTS HEREIN CONTAINED AND OTHER
GOOD AND VALUABLE CONSIDERATION, AND INTENDING TO BE LEGALLY BOUND HEREBY, THE
PARTIES AGREE AS FOLLOWS:

                                    ARTICLE 1

                                 INTERPRETATION

1.1    DEFINITIONS. In this Agreement unless specifically defined otherwise or
       the context otherwise requires, the following terms shall have the
       following meanings, and the terms defined elsewhere herein shall have the
       meanings there defined:

       (a)    "AGREEMENT" means this Omnibus Agreement and all amendments and
              supplements hereto and the terms "herein", "hereof", "hereto",
              "hereunder", and like terms refer to this Agreement.

       (b)    "BETTER OFFER" has the meaning ascribed thereto in Article 5.1
              hereof.

       (c)    "BUSINESS COMBINATION" has the meaning ascribed thereto in Article
              5.1(ii) hereof.

       (d)    "BUSINESS DAY" means any day excluding Saturday, Sunday and any
              other day which in Washington, D.C. or Montreal, Quebec is a legal
              holiday or a day on which financial institutions are authorized by
              law or by local proclamation to close.

       (e)    "CHANGE OF CONTROL" has the meaning ascribed thereto in Article
              5.1 hereof.


                                       3
<PAGE>   4


       (f)    "CLOSING" means completion of the transactions described in
              Article 9 hereof, to take place at the offices of ORBCOMM.

       (g)    "CLOSING DATE" means the date the Partners may agree upon as the
              time at which the Closing shall take place, which shall be a date
              no later than February 25, 2000.

       (h)    "COMMUNICATIONS ACT" means the Communications Act of 1934, as
              amended, and the rules and regulations promulgated thereunder.

       (i)    "CONTINUING DIRECTORS" has the meaning ascribed thereto in Article
              5.1 hereof.

       (j)    "CONVERSION NOTICE OF EXERCISE" has the meaning ascribed thereto
              in Article 3.7 hereof.

       (k)    "CONVERSION OPTION" has the meaning ascribed thereto in Article
              3.7 hereof.

       (l)    "DEFINITIVE AGREEMENTS" means this Agreement, the Partnership
              Agreement, the Master Agreement, the Procurement Agreements, the
              ORBCOMM System Construction Agreement dated as of June 30, 1993
              between OCC and ORBCOMM, the Proprietary Information and
              Non-Competition Agreement dated as of June 30, 1993 among the
              Parties, ORBCOMM USA, L.P. and ORBCOMM International Partners,
              L.P., and other agreements entered into pursuant to the terms of
              this Agreement, as such agreements may have been amended or
              restated or may be amended or restated in the future.

       (m)    "DELAYED INVOICE" has the meaning ascribed thereto in Article 3.6
              hereof.

       (n)    "DELAYED NON-INVOICED AMOUNTS" has the meaning ascribed thereto in
              Article 3.6 hereof.

       (o)    "EXISTING NON-INVOICED AMOUNTS" has the meaning ascribed thereto
              in Article 3.1 hereof.

       (p)    "FIRST EXISTING INVOICE" has the meaning ascribed thereto in
              Article 3.2.1 hereof.

       (q)    "GEMTRAK FINANCIAL STATEMENT" has the meaning ascribed thereto in
              Article 10.1.8 hereof.

       (r)    "GEMTRAK PURCHASE PRICE" has the meaning ascribed thereto in
              Article 6.2 hereof.

       (s)    "INDEMNIFIED PARTIES" has the meaning ascribed thereto in Article
              11.2 hereof.

       (t)    "INDEMNIFYING PARTY" has the meaning ascribed thereto in Article
              11.2 hereof.


                                       4
<PAGE>   5


       (u)    "INDENTURE" means the Amended and Restated Indenture dated as of
              February 9, 1999 executed among ORBCOMM, ORBCOMM Global Capital
              Corp., OCC, Teleglobe Mobile, ORBCOMM USA, ORBCOMM International
              and Marine Midland Bank.

       (v)    "MERGER" has the meaning ascribed thereto in Article 8.2 hereof.

       (w)    "ORBCOMM CANADA FINANCIAL STATEMENTS" has the meaning ascribed
              thereto in Article 10.2.7 hereof.

       (x)    "ORBCOMM CANADA PURCHASE PRICE" has the meaning ascribed thereto
              in Article 7.2 hereof.

       (y)    "PARTICIPATION PERCENTAGE" shall have the meaning ascribed thereto
              in the Partnership Agreement, the USA Partnership Agreement or the
              International Partnership Agreement, as applicable.

       (z)    "PARTNERSHIP INTERESTS" shall have the meaning ascribed thereto in
              the Partnership Agreement, the USA Partnership Agreement or the
              International Partnership Agreement, as applicable.

       (aa)   "PENDING INVOICE" has the meaning ascribed thereto in Article
              3.5.1 hereof.

       (bb)   "PENDING NON-INVOICED AMOUNTS" has the meaning ascribed thereto in
              Article 3.4 hereof.

       (cc)   "PERSON" means any individual, partnership, joint venture,
              corporation, trust, unincorporated organization, association,
              government or department or agency of a government or other
              entity.

       (dd)   "PLAN A INCENTIVE FEES" has the meaning ascribed thereto in
              Article 3.4 hereof.

       (ee)   "SECOND EXISTING INVOICE" has the meaning ascribed thereto in
              Article 3.3.1 hereof.

       (ff)   "STEEPLECHASE LEASE" has the meaning ascribed thereto in Article
              8.5 hereof.

       (gg)   "TELECOM BETTER OFFER" has the meaning ascribed thereto in Article
              5.2 hereof.

       (hh)   "TELEGLOBE PROMISSORY NOTES" means, collectively, the following
              promissory notes:

              (i)    an amended and restated unsecured promissory note dated
                     December 31, 1998 pursuant to which Orbital promised to pay
                     in a single payment and in full to the order of Teleglobe
                     Investment Corporation or assigns on December 31, 1999 the
                     principal amount of $18,612,227 together with (A) interest
                     in the amount of $2,103,087, and (B) interest accrued on
                     the unpaid principal amount from


                                       5
<PAGE>   6


                     December 31, 1998 until such principal amount is paid in
                     full at a rate per annum (computed on the basis of a
                     360-day year comprised of twelve 30-day months) equal to
                     9%; which principal amount and interest equal
                     $22,390,414.43 as of December 31, 1999;

              (ii)   an amended and restated unsecured promissory note dated
                     December 31, 1998 pursuant to which Orbital promised to pay
                     in a single payment and in full to the order of Teleglobe
                     Holding Corporation or assigns on December 31, 1999 the
                     principal amount of $3,298,844 together with (A) interest
                     in the amount of $372,752, and (B) interest accrued on the
                     unpaid principal amount from December 31, 1998 until such
                     principal amount is paid in full at a rate per annum
                     (computed on the basis of a 360-day year comprised of
                     twelve 30-day months) equal to 9%; which principal amount
                     and interest equal $3,968,491.96 as of December 31, 1999;
                     and

              (iii)  an amended and restated unsecured promissory note dated
                     August 17, 1999 pursuant to which Orbital promised to pay
                     in a single payment and in full to the order of Teleglobe
                     Investment Corp. or assigns on December 31, 1999 the
                     principal amount of $6,506,401 together with interest
                     accrued on the unpaid principal amount from August 17, 1999
                     until such principal amount is paid in full at a rate per
                     annum (computed on the basis of a 360-day year comprised of
                     twelve 30-day months) equal to 9%; which principal amount
                     and interest equal $6,722,738.83 as of December 31, 1999.

1.2    EXTENDED MEANINGS. Words importing the singular number include the plural
       and vice versa and words importing the masculine gender include the
       feminine and neuter genders and vice versa.

1.3    INTERPRETATION NOT AFFECTED BY HEADINGS. The division of this Agreement
       into articles and sections and insertion of headings is for convenience
       and reference only and shall not affect the construction or
       interpretation of this Agreement.

1.4    APPLICABLE LAW. This Agreement shall be deemed to have been made in and
       shall be interpreted in accordance with and be governed by the laws of
       the State of Delaware.

1.5    FUNDS. All dollar amounts referred to in this Agreement are in lawful
       currency of the United States of America.

1.6    SEVERABILITY. If any provision of this Agreement shall be held invalid,
       illegal or unenforceable in any jurisdiction, such invalidity, illegality
       or unenforceability shall attach only to such provision in such
       jurisdiction and shall not in any manner affect or render invalid,
       illegal or unenforceable such provision in any other jurisdiction or any
       other provision of this Agreement in any jurisdiction. Upon such
       determination that any provision is invalid, illegal or unenforceable,
       the Parties shall negotiate in good faith to modify this Agreement so as
       to effect the original intent of the Parties as closely as possible


                                       6
<PAGE>   7


       in an acceptable manner in order that the transactions contemplated
       hereby are consummated as originally contemplated to the greatest extent
       possible. Any provision of this Agreement held invalid, illegal or
       unenforceable only in part, degree or certain jurisdictions will remain
       in full force and effect to the extent not held invalid, illegal or
       unenforceable. To the extent permitted by applicable law, each Party
       waives any provision of law that renders any provision of this Agreement
       invalid, illegal or unenforceable in any respect.

1.7    NON-BUSINESS DAY. In the event that any action to be taken hereunder
       falls on a day which is not a Business Day, then such action shall be
       taken on the next succeeding Business Day.

1.8    PREAMBLE. The preamble forms an integral part of this Agreement.


                                    ARTICLE 2

                     AMENDMENTS TO THE PARTNERSHIP AGREEMENT

       The Parties agree that the Partnership Agreement shall be amended and
restated effective as of the date hereof, to reflect the following:

2.1    OCC AS LIMITED PARTNER. From the date hereof, OCC shall no longer be a
       General Partner (as defined in the Partnership Agreement) and shall
       become solely a Limited Partner (as defined in the Partnership
       Agreement). Accordingly, any and all references in the Partnership
       Agreement to "the General Partners", "any General Partners", "any General
       Partner", "each of the General Partners" or "each General Partner" shall
       be deleted and replaced by "the General Partner".

2.2    PARTNERSHIP AGREEMENT. The first four paragraphs of the Partnership
       Agreement are hereby deleted in their entirety and replaced by the
       following:

              "THIS AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP (the
              "Agreement") of ORBCOMM GLOBAL, L.P. (the "Partnership") is made
              and entered into as of January 1, 2000 by and between TELEGLOBE
              MOBILE PARTNERS, a Delaware general partnership ("Teleglobe
              Mobile"), as general partner (the "General Partner"), and ORBITAL
              COMMUNICATIONS CORPORATION, a Delaware corporation ("OCC"), and
              Teleglobe Mobile as limited partners (the "Limited Partners"). The
              General Partner and the Limited Partners are collectively referred
              to herein as the "Partners". This Agreement amends and restates
              the Restated Agreement of Limited Partnership of ORBCOMM Global,
              L.P. dated September 15, 1995, as amended by Amendment No. 1 to
              Restated Agreement of Limited Partnership of ORBCOMM Global, L.P.
              dated as of December 2, 1996 (the "1995 Agreement") and by the
              Omnibus Agreement dated as of January 1, 2000 entered into among
              the Partners, Orbital


                                       7
<PAGE>   8


              Sciences Corporation, a Delaware corporation ("Orbital"), and
              Teleglobe Inc., a Canadian corporation ("Teleglobe"), and the
              Partnership (the "Omnibus Agreement").

              WHEREAS, the Partnership was organized, in accordance with the
              provisions of the Delaware Act (as hereinafter defined), by the
              filing of a Certificate of Limited Partnership with the Secretary
              of State of the State of Delaware (the "Certificate") pursuant to
              Section 17-201 of the Delaware Act;

              WHEREAS, upon the filing of the Certificate, the Partners entered
              into an Agreement of Limited Partnership dated as of June 30, 1993
              (the "Original Agreement") and the Partnership entered into
              agreements with OCC, Orbital and Teleglobe for the development,
              construction, operation and marketing of the ORBCOMM System (as
              hereinafter defined); and

              WHEREAS, pursuant to the terms of the Omnibus Agreement, the
              Partners revised the terms of the 1995 Agreement setting forth
              their agreements with respect to the conduct of the business of
              the Partnership and each of their rights and obligations as
              Partners."

2.3    OCC. All references to "ORBCOMM" in the Partnership Agreement (unless
       followed immediately by "Global" "USA", "International" or "System") are
       hereby deleted and replaced by "OCC".

2.4    SECTION 1.4. The first sentence of Section 1.4 of the Partnership
       Agreement is hereby deleted and replaced by the following:

              "The location of the principal office of the Partnership shall be
              2455 Horse Pen Road, Herndon, Virginia 20171 or at such other
              location as may be selected from time to time by the General
              Partner, subject to Article 8.5 of the Omnibus Agreement."

2.5    SECTION 2.3A. A new Section 2.3A is hereby added to the Partnership
       Agreement and shall read as follows:

              "2.3A. Business Day. "Business Day" means any day excluding
              Saturday, Sunday and any other day which in Washington, D.C. or
              Montreal, Quebec is a legal holiday or a day on which financial
              institutions are authorized by law or by local proclamation to
              close."

2.6    SECTION 2.5. Section 2.5 of the Partnership Agreement is hereby deleted
       in its entirety.

2.7    SECTION 2.8. Section 2.8 of the Partnership Agreement is hereby deleted
       in its entirety.

2.8    SECTION 2.9. Section 2.9 of the Partnership Agreement is hereby deleted
       in its entirety.


                                       8
<PAGE>   9


2.9    SECTION 2.9A. A new Section 2.9A is hereby added to the Partnership
       Agreement and shall read as follows:

              "2.9A. Definitive Agreements. "Definitive Agreements" means this
              Agreement, the Omnibus Agreement, the Master Agreement, the
              ORBCOMM System Procurement Agreement dated as of September 12,
              1995 entered into between the Partnership and Orbital, the ORBCOMM
              Procurement Agreement dated as of February 1, 1999 entered into
              between the Partnership and Orbital, the ORBCOMM System
              Construction Agreement, the Proprietary Information and
              Non-Competition Agreement, and other agreements entered into
              pursuant to the terms of the Omnibus Agreement, as such agreements
              may have been amended or restated or may be amended or restated in
              the future."

2.10   SECTION 2.15. Section 2.15 of the Partnership Agreement is hereby deleted
       in its entirety.

2.11   SECTION 2.17. Section 2.17 of the Partnership Agreement is hereby deleted
       in its entirety.

2.12   SECTION 2.20. Section 2.20 of the Partnership Agreement is hereby deleted
       in its entirety.

2.13   SECTION 2.20A. A new Section 2.20A is hereby added to the Partnership
       Agreement and shall read as follows:

              "2.20A. Omnibus Agreement. "Omnibus Agreement" shall have the
              meaning ascribed to such term in the recitals hereto."

2.14   SECTION 2.28. Section 2.28 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "2.28. Restatement Date. "Restatement Date" means January 1,
              2000."

2.15   SECTION 2.30. Section 2.30 of the Partnership Agreement is hereby deleted
       in its entirety.

2.16   SECTION 2.35. Section 2.35 of the Partnership Agreement is hereby deleted
       in its entirety.

2.17   SECTION 3.1. Section 3.1 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "3.1. Partnership Interests. The Partnership Interests shall be
              expressed in terms of the Partners' Participation Percentages.
              Teleglobe Mobile's Participation Percentage shall be sixty-four
              point twenty-six percent (64.26%) and OCC's Participation
              Percentage shall be thirty-five point seventy-four percent
              (35.74%) as of the Restatement Date after giving effect to the
              contribution described in Subsection 3.2.2 of the Omnibus
              Agreement, subject to adjustments thereafter pursuant to Section
              3.7 hereof (such further adjustments to include, without


                                       9
<PAGE>   10


              limitation, the adjustment resulting from the contribution
              described in Subsection 3.5.2 of the Omnibus Agreement). The
              Partners shall be entitled to receive the distributions set forth
              in Sections 4 and 10."

2.18   SECTION 3.2. Section 3.2 of the Partnership Agreement is hereby deleted
       in its entirety.

2.19   SECTION 3.3. Section 3.3 of the Partnership Agreement is hereby deleted
       in its entirety.

2.20   SECTION 3.5. Section 3.5 of the Partnership Agreement is hereby deleted
       in its entirety.

2.21   SECTION 3.6. Section 3.6 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "3.6. Loans. (a) Optional Loans. The General Partner shall have
              the right to make a loan of cash to the Partnership at any time on
              such terms as the General Partner may determine; provided,
              however, that in no event shall any such optional loan be secured
              by Partnership assets, bear interest or original issue discount or
              be with recourse to any Partner.

              (b) Stock Option Plan Loans. To the extent (i) the Partnership has
              agreed to reimburse OCC for the costs paid by OCC pursuant to
              Section 6.06 of the Orbital Communications Corporation 1992 Stock
              Option Plan (including the payment by OCC of withholding taxes
              with respect to the exercise of stock options) in purchasing stock
              acquired by employees or former employees of the Partnership (the
              "Stock Option Plan Costs"), and (ii) the Partnership is permitted
              to reimburse OCC for the Stock Option Plan Costs under the terms
              of the Indenture, the Partnership shall pay to OCC the Stock
              Option Plan Costs including, without limitation, amounts owed
              under notes payable by OCC to former employees of the
              Partnership."

2.22   SECTION 3.7. Section 3.7 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "3.7. Additional Capital Contributions. If the Partnership shall
              require a capital contribution, the Partnership shall so notify
              the Partners and each Partner shall have the opportunity, but not
              the obligation, to contribute in cash or immediately available
              funds an amount equal to such capital contribution multiplied by
              such Partner's Participation Percentage. If either Partner
              declines to make a contribution within five (5) Business Days of
              the date upon which the Partnership notified the Partners of such
              requirement (it being understood that if a Partner has not
              contributed its share at the expiration of such five (5) Business
              Day-period, it will be deemed to have declined to contribute),
              then:

              (a)    The other Partner shall be entitled to contribute the
                     amount so declined to be contributed (in addition to any
                     amount such Partner is entitled to contribute


                                       10
<PAGE>   11


                     pursuant to the preceding sentence) within five (5)
                     Business Days of the date upon which the other Partner
                     declined or was deemed to have declined to contribute its
                     share, and

              (b)    Based on contributions so made, the Partners' Participation
                     Percentages shall be adjusted immediately following the
                     expiration of the five (5) Business Day-period referred to
                     in subsection (a) above as follows:

                     (i)    Teleglobe Mobile's Participation Percentage shall be
                            adjusted so as to equal the percentage equal to the
                            result of the following formula, rounded to the
                            second decimal point:

                                          299.354M + (TMAC X 1.75)
                              ----------------------------------------------
                          $465.841M + [1.75 X (TMAC + OAC)] + (OCONV X $33.082M)

                            Where:

                            M =    million

                            TMAC = the dollar amount expressed in millions
                                   rounded to the third decimal point of all
                                   contributions made by Teleglobe Mobile from
                                   January 1, 2000 to the date of determination
                                   of the Partners' Participation Percentages as
                                   provided in this Section 3.7(b), excluding
                                   the contribution referred to in Subsection
                                   3.2.2 of the Omnibus Agreement.

                            OAC =  the dollar amount expressed in millions
                                   rounded to the third decimal point of all
                                   contributions made by OCC from January 1,
                                   2000 to the date of determination of the
                                   Partners' Participation Percentages as
                                   provided in this Section 3.7(b), excluding
                                   the contribution resulting from the
                                   conversion referred to in Subsection 3.3.3 of
                                   the Omnibus Agreement.

                            OCONV = zero (0) until the conversion referred to in
                                   Subsection 3.3.3 of the Omnibus Agreement is
                                   effected and one (1) thereafter or, if such
                                   conversion is not effected as provided in
                                   such Subsection 3.3.3, then zero (0)
                                   thereafter.

                     (ii)   OCC's Participation Percentage shall be adjusted so
                            as to equal one hundred per cent (100%) minus
                            Teleglobe Mobile's Participation Percentage (so
                            adjusted)."

2.23   SECTION 4.1. Section 4.1 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:


                                       11
<PAGE>   12


              "4.1. Distributions. Subject to Sections 4.2, 4.3 and 10.3, the
              amount and timing of distributions by the Partnership, either in
              cash or property, shall be determined in the discretion of the
              General Partner, provided, however, subject to Sections 4.4 and
              10.3, that all distributions (including, without limitation, those
              made pursuant to Section 4.2) shall be made to the Partners pro
              rata in accordance with their respective Participation Percentages
              as of the date of distribution and that if the General Partner
              determines to effect a distribution both in cash and property,
              equal proportions of such cash and property shall be distributed
              to the Partners pro rata in accordance with their respective
              Participation Percentages as of the date of distribution. The
              Partners confirm that no distributions under this Section 4.1
              occurred prior to January 1, 2000."

2.24   SECTION 4.3. Section 4.3 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "4.3. Nature of Distributions. The General Partner may determine
              to make a distribution in kind or property to the Partners, but
              such property shall be distributed in such a fashion as to ensure
              that the fair value thereof is distributed and allocated in
              accordance with Sections 4, 5 and 10 hereof. For purposes of (a)
              determining amounts to be distributed to Partners under Section
              4.1, (b) determining Net Income and Net Loss under Section 5, (c)
              making adjustments to Capital Accounts under Section 5, and (d)
              allocations under Section 5, any property to be distributed in
              kind shall have the fair value assigned to such property by the
              General Partner, subject to the approval of OCC which shall not be
              unreasonably withheld or delayed, provided, however, that such
              approval shall not be required (a) if at the time such fair value
              is determined OCC's Participation Percentage is below 31.67%; or
              (b) if such fair value is determined by a major investment banking
              firm selected by the Partnership which shall not have rendered
              financial advisory services to the Partnership, Teleglobe or
              Orbital during the preceding year."

2.25   SECTION 5.1(d). Subsection (d) of Section 5.1 of the Partnership
       Agreement is hereby deleted in its entirety and replaced by the
       following:

              "(d) Adjustments to Carrying Values and Capital Accounts. In
              accordance with Treasury Regulations Section 1.704-1(b)(2)(iv)(f),
              in connection with either (i) the contribution of money or other
              property (other than a de minimis amount) to the Partnership by a
              new or existing Partner in consideration for an interest in the
              Partnership or (ii) a distribution of money or other property
              (other than a de minimis amount) by the Partnership to a retiring
              or continuing Partner as consideration for an interest in the
              Partnership, the Capital Accounts of all Partners and the Carrying
              Values of all Partnership properties may be, as determined by the
              General Partner, adjusted (consistent with the provisions hereof)
              upwards or downwards to reflect any Unrealized Gain or Unrealized
              Loss attributable to each Partnership property, as if such
              Unrealized Gain or Unrealized Loss had been


                                       12
<PAGE>   13


              recognized upon an actual sale of each such property at such time
              and had been allocated to the Partners pursuant to Section 5.2.
              For purposes of determining such Unrealized Gain or Unrealized
              Loss, the fair value of Partnership assets shall be determined by
              the General Partner using such reasonable methods of valuation as
              it in its sole discretion deems appropriate, subject to the
              approval of OCC which shall not be unreasonably withheld or
              delayed, provided, however, that such approval shall not be
              required (i) once OCC's Participation Percentage falls below 15%;
              or (ii) if such fair value is determined by a major investment
              banking firm selected by the Partnership which shall not have
              rendered financial advisory services to the Partnership, Teleglobe
              or Orbital during the preceding year.

              Without limiting the generality of the foregoing and
              notwithstanding any other provision of this Agreement, the
              proportion that the dollar amount of the Capital Account of a
              Partner bears to the dollar amount of the Capital Account of the
              other Partner shall at all times be equivalent to the proportion
              that the Participation Percentage of such Partner bears to the
              Participation Percentage of such other Partner. Accordingly, at
              any time a discrepancy arises between the respective Participation
              Percentages of the Partners, the General Partner will immediately
              adjust upwards and/or downwards the respective Capital Accounts of
              the Partners as may be required to reflect the provisions of the
              preceding sentence."

2.26   SECTION 5.1(f). Subsection (f) of Section 5.1 of the Partnership
       Agreement is hereby deleted in its entirety.

2.27   SECTION 6.1. The first paragraph of Section 6.1 of the Partnership
       Agreement is hereby deleted in its entirety and replaced by the
       following:

              "Authority of the General Partner. Except to the extent required
              by law or specific provisions of this Agreement, the management of
              the Partnership and all Partnership affairs shall be the exclusive
              responsibility of the General Partner. Without limiting the
              generality of the foregoing, subject to Sections 6.2, 6.2A, 6.2B
              and 6.3 hereof, the General Partner is authorized on behalf of the
              Partnership, without the consent of any other Partner, to:"

2.28   SECTION 6.1. The last paragraph of Section 6.1 of the Partnership
       Agreement is hereby deleted in its entirety and replaced by the
       following:

              "By executing this Agreement, each Partner shall be deemed to have
              consented to any exercise by the General Partner of any of the
              foregoing powers."

2.29   SECTION 6.2. Section 6.2 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "6.2. OCC Approval. The approval of OCC shall be required to:


                                       13
<PAGE>   14


              (a)    enter into any transaction (excluding the Definitive
                     Agreements) with an Affiliate of the General Partner;

              (b)    make on behalf of the Partnership an assignment for the
                     benefit of creditors, decide on behalf of the Partnership
                     to subject the Partnership to any proceedings under any
                     bankruptcy or insolvency law, decide to avail the
                     Partnership of the benefit of any other legislation for the
                     benefit of debtors, or take steps to wind up or terminate
                     the Partnership existence; and

              (c)    amend this Section 6.2.

              This Section 6.2 shall no longer apply and it shall be deemed
              deleted once OCC's Participation Percentage falls below 15%."

       Notwithstanding anything to the contrary, this Article 2.29 will not
       apply to any transaction effected pursuant to this Agreement including,
       without limitation, the transactions referred to in Articles 5.2 and 7
       hereof.

2.30   SECTION 6.2A. A new Section 6.2A is hereby added immediately following
       Section 6.2 of the Partnership Agreement:

              "6.2A. OCC Approval. The approval of OCC shall be required to
              amend, in a manner detrimental to OCC, the provisions of Sections
              3, 4, 5, 6.2A and 10 of this Agreement, it being understood that
              any amendment to any such Sections upon the admission of another
              Limited Partner that is not an Affiliate of the General Partner
              shall not be deemed to be detrimental to OCC if all Limited
              Partners are treated substantially equally in connection with such
              amendment."

2.31   SECTION 6.2B. A new Section 6.2B is hereby added immediately following
       Section 6.2A of the Partnership Agreement:

              "6.2B. OCC Approval. Subject to the terms hereof, the approval of
              OCC shall be required to:

              (a)    transfer all or substantially all the assets of the
                     Partnership or contract to do so;

              (b)    merge or consolidate the Partnership with any other Person;
                     provided, however, that this subsection (b) shall not be
                     applicable in the event such merger or consolidation is
                     deemed fair from a financial point of view to the
                     Partnership in the written opinion of a major investment
                     banking firm selected by the Partnership which shall not
                     have rendered financial advisory services to the
                     Partnership, Teleglobe or Orbital during the preceding
                     year;


                                       14
<PAGE>   15


              (c)    permit the entry by the Partnership into any additional
                     lines of business other than those described in Section
                     1.3, as contemplated in the Omnibus Agreement or directly
                     related thereto;

              (d)    select or remove the independent certified public
                     accountant for the Partnership pursuant to Section 8.4 or
                     adopt, or modify in any material respect, any significant
                     accounting policy or tax policy;

              (e)    determine the value of the Partnership for purposes of
                     Article X of the Master Agreement; and

              (f)    amend any provision of this Agreement; provided, however,
                     that notwithstanding any other provision of this Agreement,
                     no Partner shall delay, frustrate or otherwise interfere
                     with in any way the raising of debt or equity financing by
                     the Partnership from any Person not currently admitted to
                     the Partnership which financing has been initiated or
                     approved by the General Partner (it being understood that
                     the simultaneous raising of debt or equity financing by OCC
                     or Teleglobe Mobile shall be deemed for the purposes hereof
                     to interfere with the raising of debt or equity financing
                     by the Partnership); provided that in the case of any such
                     equity financing, the consideration expected to be received
                     by the Partnership from such financing shall be fair to the
                     Partnership as determined by the General Partner; and
                     provided further that in the case of any such equity
                     financing (executed in one transaction or a series of
                     transactions) which is intended to result in the admission
                     to the Partnership of a Person or Persons who following
                     such financing would hold a Participation Percentage or
                     Participation Percentages equal to or greater than
                     twenty-five percent (25%), the consideration expected to be
                     received by the Partnership from such financing shall be
                     fair to the Partnership, in the written opinion of a major
                     investment banking firm selected by the Partnership which
                     shall not have rendered financial advisory services to the
                     Partnership, Teleglobe or Orbital during the preceding
                     year.

              This Section 6.2B shall no longer apply and it shall be deemed
              deleted once OCC's Participation Percentage falls below 31.67%;
              provided, however, that should OCC's Participation Percentage
              return to 31.67% or higher after having fallen below 31.67% solely
              as a result of the conversion referred to in Subsection 3.3.3 of
              the Omnibus Agreement, then this Section 6.2B will apply again
              until OCC's Participation Percentage thereafter falls below
              31.67%, at which time this Section 6.2B shall no longer apply and
              it shall be deemed deleted."

2.32   SECTION 6.3. Section 6.3 of the Partnership Agreement is hereby deleted
       in its entirety.

2.33   SECTION 6.4. Section 6.4 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:


                                       15
<PAGE>   16


              "6.4. Meetings. Meetings of the Partners may be called by the
              General Partner and shall be held at the principal offices of the
              Partnership or at such other location as shall be reasonably
              determined by the General Partner. Except as otherwise specified
              in Section 8.5 hereof, the General Partner shall have no
              obligation to call a meeting of the Partners at any time.
              Notwithstanding any provision of applicable law, not less than
              forty-eight (48) hours prior written notice of the time, place and
              purpose of each meeting of the Partners shall be provided to each
              Partner, provided that any Partner may waive compliance with such
              notice requirement. Any meeting may be adjourned from time to time
              by the General Partner, and the meeting may be held as adjourned
              without further notice. Any one or more Partners may participate
              in any meeting by means of conference telephone, video or similar
              communications equipment allowing all persons participating in the
              meeting to hear each other at the same time. Participation by
              Partners in a meeting held by means of a conference telephone,
              video or similar communications equipment shall constitute
              presence in person at a meeting. Any action required or permitted
              to be taken with the approval of one or more Partners may be taken
              without a meeting upon the written consent of such Partners, which
              written consent shall be filed with the records of the meetings of
              the Partners."

2.34   SECTION 6.5. Section 6.5 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "6.5. Representation at Meetings; Reimbursement. The General
              Partner shall be represented at meetings of the Partners by up to
              three authorized officers or other authorized agents, it being the
              expectation of the General Partner that it will select three
              representatives who will use reasonable efforts to attend each
              meeting of the Partners. At each meeting of the Partners, one
              representative of the General Partner shall be entitled to vote
              such Partner's Participation Percentage. The General Partner shall
              be entitled to reimbursement of the reasonable out-of-pocket
              expenses incurred by it or its representatives in attending
              meetings of the Partners. No amount so paid to any such member
              shall be deemed to be a distribution of Partnership assets for
              purposes of this Agreement or the Delaware Act. Except for the
              reimbursement of expenses as provided in this Section 6.5, the
              General Partner or representatives thereof shall not receive any
              compensation for its, his or her services as such.

              In addition, so long as OCC's Participation Percentage is not less
              than fifteen percent (15%), then at each meeting of the Partners,
              two representatives of OCC as well as the Chief Executive Officer
              of ORBCOMM shall be entitled to be present as observers and OCC
              shall be entitled to reimbursement of expenses to the extent set
              forth for the General Partner herein with respect to its two
              representatives, except for travel expenses."

2.35   SECTION 6.8. Section 6.8 of the Partnership Agreement is hereby deleted
       in its entirety.


                                       16
<PAGE>   17


2.36   SECTION 6.9. Section 6.9 of the Partnership Agreement is hereby deleted
       in its entirety.

2.37   SECTION 8.3. The phrase "using ORBCOMM financial formats, which formats
       shall be previously approved by Teleglobe Mobile" found in Subsection (b)
       of Section 8.3 of the Partnership Agreement is hereby deleted in its
       entirety and replaced by the phrase "using Teleglobe Mobile financial
       formats, which formats shall be approved by OCC, such approval not to be
       unreasonably withheld or delayed."

2.38   SECTION 8.3. The last sentence of Subsection (b) of Section 8.3 of the
       Partnership Agreement is hereby deleted in its entirety.

2.39   SECTION 8.3. The first sentence of Subsection (c) of Section 8.3 of the
       Partnership Agreement is hereby deleted in its entirety and replaced by
       the following:

              "Teleglobe Mobile shall be the Tax Matters Partner of the
              Partnership."

       Orbital and OCC agree to provide all necessary assistance to Teleglobe
       Mobile and ORBCOMM to provide for an orderly transition of the status of
       the Tax Matter Partner (as defined in the Partnership Agreement) from OCC
       to Teleglobe Mobile, including, without limitation, the preparation of
       tax filings for the year ended December 31, 1999, the transfer of all
       previously filed tax filings and back-up documentation as well as access
       to the necessary Orbital personnel. Orbital shall be reimbursed promptly
       upon invoice for reasonable costs and expenses associated with such
       assistance.

2.40   SECTION 8.4. The words "KPMG Peat Marwick" found in Section 8.4 of the
       Partnership Agreement are hereby deleted in their entirety and replaced
       by "Arthur Andersen".

2.41   SECTION 8.5. Section 8.5 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "8.5. Review Policies. So long as OCC's Participation Percentage
              is not less than fifteen percent (15%), the financial performance
              and business of the Partnership shall be reviewed at least
              quarterly by the General Partner at a meeting of the Partners."

2.42   SECTION 10.3. Section 10.3 of the Partnership Agreement is hereby deleted
       in its entirety and replaced by the following:

              "Upon the dissolution of the Partnership, the General Partner, or,
              in the case of an Event of Withdrawal of the last remaining
              General Partner, one of the Limited Partners elected by a majority
              vote of the Limited Partners, shall act as liquidator to wind up
              the Partnership. The liquidator shall have full power and
              authority to sell, assign and encumber any or all of the
              Partnership's assets and to wind up and liquidate the affairs of
              the Partnership in an orderly and business-like manner. All
              proceeds from liquidation shall be distributed in the following
              order of priority: (a)


                                       17
<PAGE>   18


              to the payment of the debts and liabilities of the Partnership and
              expenses of liquidation; (b) to the setting up of such reserves as
              the liquidator may reasonably deem necessary for any contingent
              liability of the Partnership; and (c) the balance to the Partners
              pro rata in accordance to their respective Participation
              Percentages."

2.43   SECTION 11.1. The words "Executive Vice President, Corporate Development
       and Corporate Secretary" referred to in Section 11.1 of the Partnership
       Agreement are hereby deleted and replaced by "Vice President, Chief Legal
       Officer and Corporate Secretary."

2.44   FAIR MARKET VALUE. Any and all references to "fair market value" and
       "fair market values" in the Partnership Agreement are hereby deleted and
       replaced by "fair value" and "fair values", respectively.

2.45   AMENDED AND RESTATED PARTNERSHIP AGREEMENT. The Parties agree to execute
       concurrently with the execution of this Agreement the Amended and
       Restated Partnership Agreement attached hereto as Schedule A which gives
       effect to the amendments provided herein.

                                    ARTICLE 3

                             PROCUREMENT AGREEMENTS

3.1    EXISTING NON-INVOICED AMOUNTS. After giving effect to subparagraph (vii)
       of Section 3.1(a) of the 1995 Procurement Agreement, as provided in
       Article 3.9.1 hereof, the Parties confirm that Orbital's invoiceable but
       non-invoiced amounts to ORBCOMM under the Procurement Agreements as of
       July 1999 are equal to $66,163,290.44 (the "EXISTING NON-INVOICED
       AMOUNTS").

3.2    INVOICING OF EXISTING NON-INVOICED AMOUNTS; TELEGLOBE MOBILE
       CONTRIBUTION. Concurrently with the execution of this Agreement:

       3.2.1  Orbital will send ORBCOMM an invoice in the amount of
              $33,081,645.22, representing half of the amount of the Existing
              Non-Invoiced Amounts (the "FIRST EXISTING INVOICE");

       3.2.2  Teleglobe Mobile will contribute to ORBCOMM an amount equal to the
              First Existing Invoice by way of wire transfer in exchange for
              Partnership Interests of ORBCOMM;

       3.2.3  upon receipt of the contribution specified in Subsection 3.2.2,
              ORBCOMM will pay the First Existing Invoice to Orbital by way of
              wire transfer;


                                       18
<PAGE>   19


       3.2.4  upon receipt of the payment specified in Subsection 3.2.3, Orbital
              will pay all amounts due under the Teleglobe Promissory Notes by
              way of wire transfer as per the terms of the instructions attached
              hereto as Schedule B; and

       3.2.5  the Teleglobe Promissory Notes will be deemed to be paid in full
              and cancelled.

       Completion of the steps referred to in this Article 3.2 hereof will not
       result in an adjustment under Section 3.7 or 5.1(d) of the Partnership
       Agreement, the contribution referred to in Subsection 3.2.2 hereof being
       already reflected in Section 3.1 of the Partnership Agreement.

3.3    ADDITIONAL INVOICING OF EXISTING NON-INVOICED AMOUNTS. Subject to all
       necessary consents from lenders being granted to Orbital at the latest by
       March 31, 2000 (failing which the terms of Subsection 3.6.3 hereof will
       apply) and within three (3) Business Days of such consents being granted
       to Orbital:

       3.3.1  Orbital will send ORBCOMM a second invoice in the amount of
              $33,081,645.22, representing the other half of the amount of the
              Existing Non-Invoiced Amounts not invoiced under the First
              Existing Invoice (the "SECOND EXISTING INVOICE");

       3.3.2  Orbital will assign the Second Existing Invoice to OCC and an
              adjustment shall be made to intercompany accounts consistent with
              past practice;

       3.3.3  OCC will request ORBCOMM to convert the full amount of the Second
              Existing Invoice into a contribution to Partnership Interests of
              ORBCOMM;

       3.3.4  ORBCOMM will accept such request and the Second Existing Invoice
              will be deemed fully paid; and

       3.3.5  the respective Participation Percentages and Capital Accounts of
              the Partners will be immediately adjusted pursuant to the terms of
              Sections 3.7 and 5.1(d) of the Partnership Agreement.

       Orbital hereby undertakes to use all reasonable commercial efforts to
       obtain all of the necessary consents from lenders referred to above as
       soon as possible.

3.4    DETERMINATION OF PENDING NON-INVOICED AMOUNTS; FUTURE INVOICING. After
       giving effect to subparagraph (viii) of Section 3.1(a) of the 1995
       Procurement Agreement as provided in Article 3.9.1 hereof, the Parties
       hereby agree, subject to the following, that the invoiceable but
       non-invoiced amounts owed by ORBCOMM under the Procurement Agreements up
       to December 31, 1999, excluding the Existing Non-Invoiced Amounts, are
       equal to $25,137,209 and are referred to herein as the "PENDING
       NON-INVOICED AMOUNTS". Subject to the following sentence, it is
       understood by the Parties that the Existing Non-Invoiced Amounts and the
       Pending Non-Invoiced Amounts together represent all amounts Orbital is
       entitled to invoice under the Procurement Agreements, the Administrative


                                       19
<PAGE>   20


       Services Agreement and open task orders for the period up to and
       including December 31, 1999. Notwithstanding the preceding sentences, the
       Parties agree that an amount of $1,152,779 plus the applicable interest
       has been included in the Pending Non-Invoiced Amounts as Plane A
       incentive fees payable pursuant to Article 4 of the 1995 Procurement
       Agreement (the "PLANE A INCENTIVE FEES") regardless of the fact that the
       Plane A Incentive Fees have not yet been agreed upon by the Parties. The
       Parties agree to negotiate the Plane A Incentive Fees, if any, in good
       faith at the latest by the Closing Date. At the Closing Date, an upward
       or downward adjustment to the Pending Non-Invoiced Amounts and to the
       amounts provided in Subsections 3.5.1, 3.6.1, 3.6.2 and 3.9.1 hereof will
       be effected to give effect to the final determination of the Plane A
       Incentive Fees. The difference between the amount currently provided for
       in Subsection 3.5.1 and the re-adjusted amount, if any, to be provided
       for in Subsection 3.5.1 will be reimbursed by Orbital to ORBCOMM or paid
       by ORBCOMM to Orbital, as the case may be, at the Closing and the
       Participation Percentages and Capital Accounts of the Partners will be
       adjusted accordingly.

3.5    INVOICING OF PENDING NON-INVOICED AMOUNTS; TELEGLOBE MOBILE CONTRIBUTION.
       Concurrently with the execution of this Agreement:

       3.5.1  Orbital will send ORBCOMM an invoice in the amount of $8,379,070
              (i.e. 33 1/3% of the Pending Non-Invoiced Amounts) (the "PENDING
              INVOICE"). The balance of the Pending Non-Invoiced Amounts shall
              be paid in accordance with the provisions of Subsections 3.6.1 and
              3.6.2 hereof;

       3.5.2  upon receipt of the invoice specified in Subsection 3.5.1,
              Teleglobe Mobile will contribute to ORBCOMM an amount equal to the
              amount of the Pending Invoice by way of wire transfer in exchange
              for Partnership Interests in ORBCOMM;

       3.5.3  upon receipt of the contribution specified in Subsection 3.5.2,
              ORBCOMM will pay the Pending Invoice to Orbital by way of wire
              transfer; and

       3.5.4  the respective Participation Percentages and Capital Accounts of
              the Partners will be immediately adjusted pursuant to Sections 3.7
              and 5.1(d) of the Partnership Agreement.

3.6    INVOICING OF OTHER AMOUNTS. Subject to the last paragraph of Article 8.4
       hereof, but notwithstanding any provision of the Procurement Agreements,
       the Parties agree that:

       3.6.1  Orbital will invoice ORBCOMM under the Procurement Agreements an
              additional amount equal to $8,379,070 (i.e. 33 1/3% of the Pending
              Non-Invoiced Amounts) on March 31, 2001 (plus the applicable
              additional amounts payable pursuant to Article 3.11 hereof);

       3.6.2  Orbital will invoice ORBCOMM under the Procurement Agreements an
              additional amount equal to $8,379,069 (i.e. the balance of the
              Pending Non-


                                       20
<PAGE>   21


              Invoiced Amounts) on June 30, 2001 (plus the applicable additional
              amounts payable pursuant to Article 3.11 hereof); and

       3.6.3  in the event the transactions referred to in Article 3.3 hereof
              cannot be completed by March 31, 2000, Orbital will invoice
              ORBCOMM under the Procurement Agreements on March 31, 2001 an
              amount equal to $33,081,645.22, representing the amount referred
              to in Article 3.3.1 hereof, together with interest accrued thereon
              from March 31, 2000 through March 31, 2001 at a rate per annum
              (computed on the basis of a 360-day year comprised of twelve
              30-day months) equal to nine percent (9%).

       The amounts referred to in subsections 3.6.1, 3.6.2 and 3.6.3 hereof are
       collectively referred to herein as the "DELAYED NON-INVOICED AMOUNTS" and
       any invoice with respect to such amounts is referred to herein as a
       "DELAYED INVOICE".

3.7    ORBITAL CONVERSION OPTION. In the event that any Delayed Non-Invoiced
       Amounts are not paid by ORBCOMM within five (5) Business Days of the date
       on which they are invoiced by Orbital pursuant to Article 3.6 hereof,
       then Orbital will have the option (the "CONVERSION OPTION") to convert
       the whole of the unpaid Delayed Non-Invoiced Amounts covered by the
       applicable Delayed Invoice into a contribution to Partnership Interests
       of ORBCOMM. The Conversion Option shall be exercised by Orbital by giving
       ORBCOMM and Teleglobe Mobile notice in writing (the "CONVERSION NOTICE OF
       EXERCISE") of its intention to exercise the Conversion Option with
       respect to any applicable Delayed Invoice within twenty (20) Business
       Days following the due date of such Delayed Invoice, failing which the
       Conversion Option with respect to such Delayed Invoice will be cancelled.
       Orbital shall not have the right to assign the Conversion Option.
       Completion of the exercise of the Conversion Option with respect to any
       applicable Delayed Invoice shall take place at the offices of ORBCOMM at
       11:00 a.m. (local time) on the third (3rd) Business Day following receipt
       by both ORBCOMM and Teleglobe Mobile of the applicable Conversion Notice
       of Exercise and shall proceed as follows:

       3.7.1  Orbital will assign the applicable invoice to OCC and an
              adjustment shall be made to intercompany accounts consistent with
              past practice;

       3.7.2  OCC will request ORBCOMM to convert the full unpaid amount of such
              applicable invoice into a contribution to Partnership Interests of
              ORBCOMM;

       3.7.3  ORBCOMM will accept such request and such applicable invoice shall
              be deemed fully paid; and

       3.7.4  an adjustment to the Participation Percentages and the Capital
              Accounts of each of the Partners pursuant to Sections 3.7 and
              5.1(d) of the Partnership Agreement or any other similar provision
              then in effect dealing with the treatment of additional
              contributions by Partners will be immediately effected.


                                       21
<PAGE>   22


       Notwithstanding any provision in Article 3.6 and 3.7 to the contrary, in
       the event that ORBCOMM fails to pay amounts due and payable to Orbital
       under the Procurement Agreements (other than amounts disputed in good
       faith by ORBCOMM in accordance with the terms of the Procurement
       Agreements), then the Delayed Non-Invoiced Amounts shall become, if such
       failure continues for five (5) Business Days following written notice
       thereof by Orbital to ORBCOMM and Teleglobe Mobile, due and payable and
       Orbital shall have the option to convert the entire Delayed Non-Invoiced
       Amounts (other than amounts disputed in good faith by ORBCOMM in
       accordance with the terms of the Procurement Agreements) into a
       contribution to Partnership Interests of ORBCOMM. If Orbital decides to
       exercise such option to convert, it shall provide written notice of
       exercise to ORBCOMM and Teleglobe Mobile within five (5) Business Days of
       the expiration of the five (5) Business Day-period referred to above and
       the option shall be exercisable by Orbital on the second (2nd) Business
       Day following the sending of such written notice and shall proceed as set
       forth in Articles 3.7.1 to 3.7.4 herein. For the purposes of this
       paragraph, the amendments to be effected pursuant to Article 3.11 will be
       effected as of the date the unpaid amounts are paid by ORBCOMM or, if the
       option to convert is exercised by Orbital, as of the date of conversion.

3.8    ACCESS AND INVESTIGATION. From the date of this Agreement, Orbital will
       afford Teleglobe, ORBCOMM and their representatives full and free access
       to Orbital's personnel, properties, contracts, books and records, and
       other documents and data as Teleglobe and ORBCOMM may reasonably request
       in order to validate Orbital's invoices under the Procurement Agreements.

3.9    AMENDMENTS TO 1995 PROCUREMENT AGREEMENT. The 1995 Procurement Agreement
       shall be amended as follows:

       3.9.1  ARTICLE 3.1(a). Article 3.1(a) of the 1995 Procurement Agreement
              shall be amended to add new subparagraphs (vii) and (viii)
              immediately following subparagraph (vi) that read as follows:

              "(vii)  Price Adjustment Changes From
                      October 1, 1999 to December 31, 1999
                      Outside the General Scope of the Agreement    $1,194,673

              "(viii) Price Adjustment Changes through
                      December 31, 1999 Outside
                      the General Scope of the Agreement            $555,467"

       3.9.2  ARTICLE 3.1(a). Article 3.1(a) of the 1995 Procurement Agreement
              shall be amended to delete the "TOTAL" price of $169,505,816 set
              forth therein and to replace it with the new "TOTAL" price of
              $171,255,956.

       3.9.3  ARTICLE 4.1(b)(i). Article 4.1(b)(i) of the 1995 Procurement
              Agreement shall be deleted in its entirety and replaced with the
              following:


                                       22
<PAGE>   23


              "(i) Orbital shall be entitled to invoice ORBCOMM Global on a
              monthly basis for a maximum of 90% of its costs incurred during
              such month, other than costs associated with Sections 3.1(a)(iv),
              3.1(a)(v), 3.1(a)(vi), 3.1(a)(vii), 3.1(a)(viii), 3.1(c) and
              3.1(d), plus to the extent permitted by Section 4.1(f), such
              portion of the cost in excess of the maximum amount to be invoiced
              to ORBCOMM Global in accordance with such Section 4.1(f) and not
              previously invoiced and paid; provided, however, that Orbital
              shall not be entitled to invoice ORBCOMM Global under Section
              4.1(a) and this Section 4.1(b)(i) in a cumulative total amount
              greater than $126,390,568."

       3.9.4  ARTICLE 4.4(ii). Article 4.4(ii) of the 1995 Procurement Agreement
              is hereby deleted in its entirety.

3.10   AMENDMENTS TO 1999 PROCUREMENT AGREEMENT. ORBCOMM and Orbital hereby
       agree to finalise by the Closing Date the manner by which the Exercised
       Optional Satellite Allocated Costs, the Exercised Optional Satellite
       Allocated Price, the Exercised Optional Satellite Difference Credit, the
       Propulsion Ring Actual Price, and the Propulsion Ring Difference Credit
       (as such terms are defined in the 1999 Procurement Agreement) are to be
       calculated under the 1999 Procurement Agreement, as well as the manner in
       which these amounts are to be paid, and to do so along the lines set
       forth in Schedule C hereto.

3.11   FURTHER AMENDMENTS TO PROCUREMENT AGREEMENTS. The Parties agree to
       execute an amendment to the 1995 Procurement Agreement and/or the 1999
       Procurement Agreement effective as of March 31, 2000 or June 30, 2000, as
       applicable, in a form similar to Article 3.9 hereof or any other
       acceptable form, which will provide for a price adjustment under such
       Procurement Agreements equal to the interest accrued on the Delayed
       Non-Invoiced Amounts from January 1, 2000 until March 31, 2001 for the
       amount referred to in Article 3.6.1 hereof and until June 30, 2001 for
       the amounts referred to in Articles 3.6.2 and 3.6.3 hereof, at a rate per
       annum (computed on the basis of a 360-day year comprised of twelve 30-day
       months) equal to 9%.

3.12   PROCUREMENT AGREEMENT RELATED ITEMS. Orbital will proceed, at the latest
       by the Closing Date, to transfer to ORBCOMM all source codes,
       documentation, and related tools required for ORBCOMM to maintain and
       upgrade as required and on its own the on-board satellite software.

3.13   1995 PROCUREMENT AGREEMENT. The last two sentences of Article 13.2 of the
       1995 Procurement Agreement are hereby deleted in their entirety and
       replaced by the following:

              "To the extent that ORBCOMM Global designs modifications to the
              Background Information, it shall have the right to implement such
              modifications; provided, however, that if ORBCOMM Global decides
              to implement such modifications without the prior written consent
              of Orbital and the Satellites on which such modifications were
              implemented become non-Working Satellites thereafter, the


                                       23
<PAGE>   24


              unpaid portion of the On-orbit Performance Incentive Payment shall
              become payable thirty (30) days after the failure by ORBCOMM
              Global to reasonably demonstrate that such modifications have not
              caused such otherwise Working Satellites to become non-Working
              Satellites. ORBCOMM Global will have up to one hundred and eighty
              (180) days from the date the Working Satellites become non-Working
              Satellites to make the demonstration referred to in the preceding
              sentence."

3.14   1999 PROCUREMENT AGREEMENT. The last two sentences of Article 13.2 of the
       1999 Procurement Agreement are hereby deleted in their entirety and
       replaced by the following:

              "To the extent that ORBCOMM Global designs modifications to the
              Background Information, it shall have the right to implement such
              modifications; provided, however, that if ORBCOMM Global decides
              to implement such modifications without the prior written consent
              of Orbital and the Satellites on which such modifications were
              implemented become non-functional Satellites thereafter, the
              unpaid portion of the Incentive Fee shall become payable thirty
              (30) days after the failure by ORBCOMM Global to reasonably
              demonstrate that such modifications have not caused such otherwise
              functional Satellites to become non-functional Satellites. ORBCOMM
              Global will have up to one hundred and eighty (180) days from the
              date the functional Satellites become non-functional Satellites to
              make the demonstration referred to in the preceding sentence."

3.15   INTERPRETATION. To the extent required, this Article 3 constitutes an
       amendment to the terms of the Procurement Agreements. If the terms of
       this Agreement contradict the terms of the Procurement Agreements, this
       Agreement shall prevail.

                                    ARTICLE 4

                                ACKNOWLEDGEMENTS

4.1    OWNERSHIP OF ORBCOMM. The Parties confirm that, as of the date hereof
       after giving effect to the amendments to the Partnership Agreement
       referred to in Article 2 hereof (including the contribution referred to
       in Subsection 3.2.2 hereof but excluding the contribution referred to in
       Subsection 3.5.2 hereof), the Partners' respective Partnership
       Percentages and Capital Accounts in ORBCOMM are summarized as follows:

<TABLE>
       <S>                                             <C>
       Teleglobe Mobile Participation Percentage:      64.26%
                                                       (as calculated in Schedule D hereof)
       OCC Participation Percentage:                   35.74%
                                                       (as calculated in Schedule D hereof)
</TABLE>


                                       24
<PAGE>   25


4.2    CALCULATION EXAMPLES. Attached as Schedule E hereto are examples of the
       application of the formula provided for in Section 3.7(b) of the
       Partnership Agreement, as amended pursuant to Article 2.21 hereof, the
       first example showing the result of the contribution referred to in
       Subsection 3.5.2 hereof.

4.3    OWNERSHIP OF ORBCOMM USA. The Parties confirm that, as of the date hereof
       immediately before giving effect to the Merger, ORBCOMM's and OCC's
       respective Partnership Interests in ORBCOMM USA are as follows:

       ORBCOMM Participation Percentage:              98%
       OCC Participation Percentage:                  2%

4.4    OWNERSHIP OF ORBCOMM INTERNATIONAL. The Parties confirm that, as of the
       date hereof immediately before giving effect to the Merger, ORBCOMM's and
       Teleglobe Mobile's respective Partnership Interests in ORBCOMM
       International are as follows:

       ORBCOMM Participation Percentage:              98%
       Teleglobe Mobile Participation Percentage:     2%

                                    ARTICLE 5

                                 RIGHT TO MATCH

5.1  ORBITAL. In the event ORBCOMM shall request proposals for the
     construction, integration, test, launch and operation of satellites not
     currently covered or to be covered under the Procurement Agreements, then
     ORBCOMM will grant Orbital an opportunity to bid on all such requests. The
     requests for proposals will not contain any specifications written
     specifically and deliberately to exclude Orbital; provided, however, that
     specifications written to permit ORBCOMM to address what ORBCOMM, in good
     faith, believes are the technical, commercial and other requirements with
     respect to its business will not be deemed to have been written
     specifically and deliberately to exclude Orbital. Upon completion of the
     bidding process, if ORBCOMM determines in its reasonable discretion that
     the terms and conditions (technical, financial and otherwise, taken as a
     whole) of an offer other than the Orbital offer are better than those of
     the Orbital offer (the "BETTER OFFER"), then ORBCOMM will submit the terms
     and conditions of the Better Offer to Orbital and Orbital will have five
     (5) Business Days to match such Better Offer. If Orbital does not respond
     in writing stating that it matches all the terms and conditions of the
     Better Offer within such time constraint, it will have the same effect as
     Orbital refusing to match the Better Offer and ORBCOMM will be free to
     accept the Better Offer. If the Better Offer is matched by Orbital, ORBCOMM
     and Orbital will negotiate in good faith the terms and conditions of a
     procurement agreement to be executed within thirty (30) days. If ORBCOMM
     and Orbital cannot agree on the terms and conditions of


                                       25
<PAGE>   26


        the procurement agreement within such thirty (30) day-period acting
        reasonably, ORBCOMM will be free to negotiate and contract with any
        other party. This Article 5.1 shall no longer apply and be deemed
        deleted upon a Change of Control of Orbital. For the purposes of this
        Article 5.1, a "CHANGE OF CONTROL" shall mean:

       (i)    the acquisition by any Person, or any Persons acting jointly or in
              concert, whether directly or indirectly, of voting securities of
              Orbital which, together with all other voting securities of
              Orbital held by such Persons, constitute, in the aggregate, either
              (a) fifty percent (50%) or more of all outstanding voting
              securities of Orbital, or (b) forty percent (40%) or more of all
              outstanding voting securities of Orbital and is followed within
              twenty-four (24) months of such acquisition by changes of the
              members of the Board of Directors of Orbital as a result of which
              the majority of the Board of Directors of Orbital consists of
              individuals other than Continuing Directors (as defined below);

       (ii)   a merger, consolidation, reorganization or other form of business
              combination (collectively, a "BUSINESS COMBINATION") of Orbital
              with another entity which results in the holders of voting
              securities of that other entity holding, in the aggregate, either
              (a) fifty percent (50%) or more of all outstanding voting
              securities of the entity resulting from the Business Combination,
              or (b) forty percent (40%) or more of all outstanding voting
              securities of the entity resulting from the Business Combination
              and is followed within twenty-four (24) months of such Business
              Combination by changes of the members of the Board of Directors of
              Orbital as a result of which the majority of the Board of
              Directors of Orbital consists of individuals other than Continuing
              Directors;

       (iii)  any event or series of events (which event or series of events may
              include, without limitation, a proxy fight or proxy solicitation
              with respect to the election of directors of Orbital made in
              opposition to the nominees recommended by the Continuing Directors
              during any period of twenty-four (24) consecutive months) as a
              result of which a majority of the members of the Board of
              Directors of Orbital consists of individuals other than Continuing
              Directors;

       (iv)   the sale, lease or exchange of all or substantially all of the
              property of Orbital to another Person, other than to any of its
              subsidiaries in the ordinary course of business of Orbital, it
              being understood that the sale, lease or exchange of all or
              substantially all of the satellite manufacturing business
              conducted by Orbital shall be deemed to constitute a sale, lease
              or exchange of all or substantially all of the property of Orbital
              for purposes of this Subsection (iv); or

       (v)    an assignment by Orbital for the benefit of its creditors, any
              proceedings under any bankruptcy or insolvency law involving
              Orbital, the decision by Orbital to


                                       26
<PAGE>   27


              avail itself of the benefit of any legislation for the benefit of
              debtors, or the taking of steps to wind up or terminate Orbital's
              existence.

       In addition, for purposes of this Article 5.1, "CONTINUING DIRECTORS"
       shall mean with respect to any period of twenty-four (24) consecutive
       months, (a) any members of the Board of Directors of Orbital on the first
       (1st) day of such period, (b) any members of the Board of Directors of
       Orbital elected after the first (1st) day of such period at any annual
       meeting of shareholders who were nominated by the Board of Directors of
       Orbital or a committee thereof, if a majority of the members of the Board
       of Directors of Orbital or such committee were Continuing Directors at
       the time of such nomination, and (c) any members of the Board of
       Directors of Orbital elected to succeed Continuing Directors by the Board
       of Directors of Orbital or a committee thereof, if a majority of the
       members of the Board of Directors of Orbital or such committee were
       Continuing Directors at the time of such election.

5.2    TELEGLOBE. From the date hereof, every time ORBCOMM wishes to purchase
       voice, data and Internet telecommunications services in an aggregate
       amount in excess of $100,000, it will grant Teleglobe (or any affiliate
       thereof) an opportunity to bid for all of its outsourced voice, data and
       Internet telecommunications needs. The request for proposals will be made
       upon customary terms for such types of services, without any
       out-of-commerce specifications other than those specifically required for
       purposes of the activities to be conducted by ORBCOMM. Teleglobe (or any
       affiliate thereof) will have the right to select which of the voice, data
       and Internet telecommunications needs it will bid upon. Upon completion
       of the bidding process, if ORBCOMM determines in its reasonable
       discretion that the terms and conditions (technical, financial and
       otherwise, taken as a whole) of an offer other than the Teleglobe offer
       are better than those of the Teleglobe offer (the "TELECOM BETTER
       OFFER"), then ORBCOMM will submit the terms and conditions of the Telecom
       Better Offer to Teleglobe and Teleglobe will have five (5) Business Days
       to match such Telecom Better Offer. If Teleglobe does not respond in
       writing stating that it matches all the terms and conditions of the
       Better Offer within such time constraint, it will have the same effect as
       Teleglobe refusing to match the Telecom Better Offer and ORBCOMM will be
       free to accept the Telecom Better Offer. If the Telecom Better Offer is
       matched by Teleglobe, the parties will proceed to the implementation of
       the services within thirty (30) days.


                                    ARTICLE 6

                                     GEMTRAK

6.1    PURCHASE AND SALE. Subject to the terms and conditions herein contained,
       Orbital and ORBCOMM or any affiliate thereof hereby agree to execute at
       Closing an asset purchase agreement pursuant to which Orbital will sell,
       transfer and assign to ORBCOMM or any


                                       27
<PAGE>   28


       affiliate thereof, and ORBCOMM or any affiliate thereof will purchase and
       accept from Orbital, the GEMtrak Business. The asset purchase agreement
       will be prepared in a form customary for similar transactions and will
       include, without limitation, customary representations and warranties as
       at March 31, 1999 and a list of purchased and excluded assets and assumed
       and non-assumed liabilities. The purchase and sale of the GEMtrak
       Business will be structured (i) so as to comply with the terms of the
       Indenture, and (ii) in the most efficient tax manner for, to the extent
       possible, all Parties involved, with Orbital's tax objectives prevailing.

6.2    PURCHASE PRICE. The price payable by ORBCOMM or any affiliate thereof to
       Orbital for the GEMtrak Business will be agreed upon in good faith
       between Orbital and Teleglobe, with the assistance of Booz Allen &
       Hamilton Inc. (the "GEMTRAK PURCHASE PRICE"). It is the current
       expectation of the Parties that the GEMtrak Purchase Price will be
       approximately equal to the ORBCOMM Canada Purchase Price. The Parties
       agree to provide Booz Allen & Hamilton Inc. with all required information
       in connection with the provision by it of such assistance. In the event
       Orbital and Teleglobe cannot agree on the GEMtrak Purchase Price by
       February 4, 2000, Orbital and Teleglobe will immediately mandate Bear
       Stearns & Co. to determine, at the latest by February 18, 2000, the fair
       value of the GEMtrak Business, in which case Orbital and Teleglobe agree
       that the GEMtrak Purchase Price will be the fair value of the GEMtrak
       Business as so determined by Bear Stearns & Co. The fees of Bear Stearns
       & Co. will be shared equally between Orbital and Teleglobe.

6.3    EFFECTIVE TIME OF SALE. The purchase and sale of the GEMtrak Business
       will occur and take effect as of the Closing Date.

6.4    PAYMENT. The GEMtrak Purchase Price will be payable in full on the
       Closing Date in a form to be agreed upon between the Parties.

6.5    ACCESS AND INVESTIGATION. Between the date of this Agreement and the
       Closing Date, Orbital will, and will cause its representatives to, afford
       ORBCOMM, Teleglobe and their representatives full and free access to
       Orbital's (as it relates to GEMtrak) personnel, properties, contracts,
       books and records, and other documents and data as ORBCOMM or Teleglobe
       may reasonably request.

6.6    OPERATION OF GEMTRAK BUSINESS. Between the date of this Agreement and the
       Closing Date, Orbital will not act so as to modify the current business
       organization of the GEMtrak Business and the relations and goodwill with
       suppliers, customers, landlords, creditors, employees, agents, and others
       having business relationships with the GEMtrak Business.

6.7    NON COMPETE. Orbital acknowledges that it has become familiar with the
       proprietary aspects of the GEMtrak Business including certain of the
       confidential information and trade secrets related to the GEMtrak
       Business and covenants and agrees that it shall not and shall cause its
       subsidiaries and affiliates not to, for a period of three (3) years from
       the date hereof, solely or jointly, on its own behalf or on behalf of any
       Person, directly or indirectly,


                                       28
<PAGE>   29


       in any capacity whatsoever including but not limited to, as a partner,
       shareholder, owner or otherwise:

       6.7.1  except in connection with the fulfillment of their respective
              obligations under any of the Definitive Agreements, carry on,
              engage, participate, invest or have an equity interest in, or have
              any financial interest in the developing, designing,
              manufacturing, and marketing and selling to commercial customers
              of automated tracking and cargo status data systems for unpowered
              mobile assets such as truck trailers, railcars and containers; or

       6.7.2  assist in or influence the engagement or hiring by any Person that
              competes with the GEMtrak Business of any salesman, distributor,
              or employee of the GEMtrak Business or otherwise cause any Person
              having a business relationship with the GEMtrak Business to sever
              such relationship with the GEMtrak Business.

       None of Orbital, its subsidiaries or its affiliates shall be in default
       under this Article 6.7 by virtue of holding for portfolio purposes as a
       passive investor not more than five percent (5%) of the issued and
       outstanding equity securities of a corporation, the securities of which
       are listed or quoted on a stock exchange or on an over-the-counter market
       within the United States or Canada.

                                    ARTICLE 7

                                 ORBCOMM CANADA

7.1    PURCHASE AND SALE. Subject to the terms and conditions herein contained,
       Teleglobe or any affiliate thereof and ORBCOMM or any affiliate thereof
       hereby agree to execute at Closing an agreement pursuant to which
       Teleglobe or any affiliate thereof will sell, transfer and assign to
       ORBCOMM or any affiliate thereof, and ORBCOMM or any affiliate thereof
       will purchase and accept from Teleglobe or any affiliate thereof, the
       business currently conducted by ORBCOMM Canada. The agreement will be
       either a share, subscription, merger or asset purchase agreement, will be
       prepared in a form customary for similar transactions and will include,
       without limitation, customary representations and warranties. The
       purchase and sale of the business of ORBCOMM Canada will be structured
       (i) so as to comply with the terms of the Indenture, and (ii) in the most
       efficient tax manner for, to the extent possible, all Parties involved
       with Teleglobe's tax objectives prevailing, including, without
       limitation, by crystallizing Teleglobe's participation in ORBCOMM Canada
       through the cancellation of outstanding common shares of ORBCOMM Canada,
       their replacement by preferred shares redeemable at the holder's option
       and the issuance of new common shares of ORBCOMM Canada to ORBCOMM or an
       affiliate thereof. Teleglobe will use its reasonable commercial efforts
       to sell 100% of the business of ORBCOMM


                                       29
<PAGE>   30


       Canada to ORBCOMM or any affiliate thereof, including the interest held
       by Meder Communications Inc.

7.2    PURCHASE PRICE. The price payable by ORBCOMM or any affiliate thereof to
       Teleglobe or any affiliate thereof for the business of ORBCOMM Canada
       will be agreed upon in good faith between Orbital and Teleglobe, with the
       assistance of Booz Allen & Hamilton Inc. (the "ORBCOMM CANADA PURCHASE
       PRICE"). It is the current expectation of the Parties that the ORBCOMM
       Canada Purchase Price will be approximately equal to the GEMtrak Purchase
       Price. The Parties agree to provide Booz Allen & Hamilton Inc. with all
       required information in connection with the provision by it of such
       assistance. In the event Orbital and Teleglobe cannot agree on the
       ORBCOMM Canada Purchase Price by February 4, 2000, Orbital and Teleglobe
       will immediately mandate Bear Stearns & Co. to determine, at the latest
       by February 18, 2000, the fair value of ORBCOMM Canada, in which case
       Orbital and Teleglobe agree that the ORBCOMM Canada Purchase Price will
       be the fair value of ORBCOMM Canada as so determined by Bear Stearns &
       Co. The fees of Bear Stearns & Co. will be shared equally between Orbital
       and Teleglobe.

7.3    EFFECTIVE TIME OF SALE. The purchase and sale of the business of ORBCOMM
       Canada will occur and take effect as of the Closing Date.

7.4    PAYMENT. The ORBCOMM Canada Purchase Price is payable in full on the
       Closing Date in a form to be agreed upon between the Parties.

7.5    ACCESS AND INVESTIGATION. Between the date of this Agreement and the
       Closing Date, Teleglobe will, and will cause ORBCOMM Canada and its
       representatives to, afford ORBCOMM, Orbital and their representatives
       full and free access to ORBCOMM Canada's personnel, properties,
       contracts, books and records, and other documents and data as ORBCOMM or
       Orbital may reasonably request.

7.6    OPERATION OF THE BUSINESS OF ORBCOMM CANADA. Between the date of this
       Agreement and the Closing Date, Teleglobe will, and will cause ORBCOMM
       Canada to, conduct the business of ORBCOMM Canada only in the normal
       course, use their best efforts to preserve intact the current business
       organization of ORBCOMM Canada and maintain the relations and goodwill
       with suppliers, customers, landlords, creditors, employees, agents, and
       others having business relationships with ORBCOMM Canada, and confer with
       ORBCOMM concerning operational matters of a material nature. Teleglobe
       will cause all indebtedness owed to ORBCOMM Canada by either Teleglobe or
       any of its affiliates to be paid in full prior to Closing.

7.7    NON COMPETE. Teleglobe acknowledges that it has become familiar with the
       proprietary aspects of the business conducted by ORBCOMM Canada including
       certain of the confidential information and trade secrets related to the
       such business and covenants and agrees that it shall not and shall cause
       its subsidiaries and affiliates not to, for a period of three (3) years
       from the date hereof, solely or jointly, on its own behalf or on behalf
       of any


                                       30
<PAGE>   31


       Person, directly or indirectly, in any capacity whatsoever including but
       not limited to, as a partner, shareholder, owner or otherwise:

       7.7.1  except in connection with the fulfillment of their respective
              obligations under any of the Definitive Agreements, carry on,
              engage, participate, invest or have an equity interest in, or have
              any financial interest in the marketing or selling in Canada of
              commercial low-Earth orbit non-voice satellite communications
              services operating in the 137-150 MHz band or such other frequency
              allocated to "little LEO" mobile satellite services below 1 GHz;
              or

       7.7.2  assist in or influence the engagement or hiring by any Person that
              competes with the business conducted by ORBCOMM Canada of any
              salesman, distributor, or employee of ORBCOMM Canada or otherwise
              cause any Person having a business relationship with ORBCOMM
              Canada to sever such relationship with ORBCOMM Canada.

       None of Teleglobe, its subsidiaries or its affiliates shall be in default
       under this Article 7.7 by virtue of holding for portfolio purposes as a
       passive investor not more than five percent (5%) of the issued and
       outstanding equity securities of a corporation, the securities of which
       are listed or quoted on a stock exchange or on an over-the-counter market
       within the United States or Canada.

                                    ARTICLE 8

                                OTHER AGREEMENTS

8.1    PRESS RELEASE AND SEC FILINGS. Upon the execution of this Agreement,
       Teleglobe and Orbital will disseminate the press release attached hereto
       as Schedule F, and ORBCOMM will promptly file such press release with the
       United States Securities and Exchange Commission on Form 8-K or other
       appropriate form.

8.2    MERGER. Each of the Partners agrees to contribute their respective
       Partnership Interests in ORBCOMM USA and ORBCOMM International to ORBCOMM
       upon the execution of this Agreement (the "MERGER") and, to that effect,
       to take such actions and execute such documents, including, without
       limitation, the agreements in a form substantially similar to the
       agreements attached hereto as Schedule G, as ORBCOMM may reasonably
       request in order to effect the Merger. The System Charge Agreements will
       terminate upon the effective date of the Merger.

8.3    ADMINISTRATIVE SERVICES AGREEMENT. The Administrative Services Agreement
       will terminate upon the Closing Date and all relevant provisions will be
       included in the sublease to be executed pursuant to Article 8.6 hereof.


                                       31
<PAGE>   32


8.4    FCC LICENSES. Orbital and OCC agree to:

       8.4.1  within three (3) Business Days of the date by which an aggregate
              of seventy-five million dollars ($75,000,000) in capital
              contributions or similar equity interests will have been made to
              ORBCOMM by any Person from January 1, 2000 (excluding
              contributions referred to in Subsections 3.2.2 and 3.3.3 hereof
              but including the contribution referred to in Subsection 3.5.2
              hereof), file an application with the FCC for the transfer of the
              FCC Licenses to ORBCOMM, in a form reasonably satisfactory to
              ORBCOMM; provided, however, that ORBCOMM shall have paid all
              amounts invoiced under the Procurement Agreements as permitted
              hereunder (other than with respect to amounts that ORBCOMM in good
              faith has given notice of dispute thereof);

       8.4.2  as may be requested by ORBCOMM, provide all necessary support for
              such transfer to occur at the earliest time possible following its
              filing;

       8.4.3  as may be requested by ORBCOMM, support all of ORBCOMM's future
              applications, petitions and communications with the FCC against
              payment of all reasonable out-of-pocket expenses incurred in doing
              so; and

       8.4.4  take such actions and execute such documents as ORBCOMM may
              reasonably request in order to effect such obligations.

       In the event the satisfactory filing referred to in Subsection 8.4.1
       hereof does not occur on the date indicated, Orbital will no longer be
       entitled to invoice ORBCOMM for any amount, under the Procurement
       Agreements or otherwise, and the application of Article 5.1 will be
       suspended until such satisfactory filing occurs.

8.5    STEEPLECHASE LEASE. The Parties agree that Orbital shall sublease to
       ORBCOMM the building (not the land) to be developed on Lot 8A, The
       Corporate Center at Steeplechase, in compliance with the terms of the
       Lease Agreement executed between Boston Properties Limited Partnership
       and Orbital as of April 15, 1999 (the "STEEPLECHASE LEASE"). Such
       sublease agreement will have payment terms consistent with the terms of
       the Steeplechase Lease with respect to the square footage of such
       building (not the land) covered by such sublease agreement without any
       mark-up being charged or retained by Orbital. The sublease agreement
       shall be executed at Closing, shall be assignable with the prior written
       consent of Orbital which shall not be unreasonably withheld or delayed
       and will be effective as of the Lease Commencement Date as defined in the
       Steeplechase Lease. Orbital agrees that it will not have the right to
       terminate such sublease agreement otherwise than in accordance with the
       terms of the Steeplechase Lease. The sublease agreement will also provide
       that ORBCOMM's employees will have access to Orbital's employee cafeteria
       located nearest to the premises described above. In addition, at Closing,
       Teleglobe will indemnify Orbital with respect to amounts payable by
       ORBCOMM under such sublease agreement for a period of one year from the
       date of ORBCOMM's default under such sublease agreement, the whole upon
       terms and conditions to be negotiated in good faith


                                       32
<PAGE>   33


       between Orbital and Teleglobe, provided, however, that such
       indemnification shall not apply to accelerated monetary obligations.

8.6    NETWORK OPERATION CENTER LEASE. The Parties agree that Orbital and
       ORBCOMM will enter at Closing into a sub-lease agreement with respect to
       that portion of the premises where ORBCOMM's Network Operation Center and
       engineering and other services are located and where ORBCOMM employees
       will remain in the Orbital Dulles facilities located on Atlantic
       Boulevard. Such sublease agreement will consist of a flow-through of the
       lease amounts and operating expenses payable by Orbital with respect to
       the square footage covered by such sublease agreement without any mark-up
       being charged or retained by Orbital. Orbital agrees that it will not
       have the right to terminate such sublease agreement, otherwise than upon
       the expiration of the term of the main lease (if not renewed), without
       ORBCOMM's prior written consent, which can be withheld for any reason. In
       addition, if ORBCOMM so requests upon six-month prior written notice,
       Orbital will terminate such sublease agreement but will be entitled to
       the reimbursement of reasonable expenses incurred in order to comply with
       the terms of the main lease relating to the reinstatement of such
       premises to the physical state provided for in the main lease.

8.7    HORSE PEN ROAD LEASE. At Closing (i) Orbital will enter into a sublease
       agreement with ORBCOMM with respect to Orbital's subleasing of 25,000
       square feet of the building located at 2455 Horse Pen Road, Herndon,
       Virginia, such sublease agreement to commence on the Lease Commencement
       Date under the Steeplechase Lease and to have payment terms consistent
       with the terms of the main lease with respect to the square footage
       covered by such sublease agreement without any mark-up being charged or
       retained by ORBCOMM, and (ii) Teleglobe will indemnify Orbital with
       respect to ORBCOMM's obligations (to the extent not assumed by Orbital)
       under the main lease for Horse Pen Road, upon terms and conditions to be
       negotiated in good faith between Orbital and Teleglobe.


                                    ARTICLE 9

                                     CLOSING

9.1    CLOSING OBLIGATIONS. The Parties acknowledge and agree that the following
       steps and actions will occur on the Closing Date:

       9.1.1  The Parties will complete or confirm in writing completion of the
              transactions referred to in Article 3.10 and Article 3.12 hereof;

       9.1.2  Orbital and ORBCOMM or an affiliate thereof will execute an asset
              purchase agreement to give effect to the provisions of Article 6
              hereof;


                                       33
<PAGE>   34


       9.1.3  Teleglobe or an affiliate thereof and ORBCOMM or an affiliate
              thereof will execute a share purchase agreement, an asset purchase
              agreement or any other agreement to give effect to the provisions
              of Article 7 hereof; and

       9.1.4  Orbital and ORBCOMM will complete the transactions referred to in
              Articles 8.5, 8.6 and 8.7 hereof;

       9.1.5  Orbital and OCC will deliver a certificate executed by Orbital and
              OCC representing and warranting to Teleglobe, Teleglobe Mobile and
              ORBCOMM that each of Orbital's and OCC's representations and
              warranties in Article 10.1 and elsewhere in this Agreement was
              accurate in all respects as of the date of this Agreement and is
              accurate in all respects as of the Closing Date as if made on the
              Closing Date and that each of Orbital's and OCC's covenants and
              undertakings to be executed on or prior to the Closing Date under
              this Agreement have been executed; and

       9.1.6  Teleglobe and Teleglobe Mobile will deliver a certificate executed
              by Teleglobe and Teleglobe Mobile representing and warranting to
              Orbital, OCC and ORBCOMM that each of Teleglobe's and Teleglobe
              Mobile's representations and warranties in Article 10.2 and
              elsewhere in this Agreement was accurate in all respects as of the
              date of this Agreement and is accurate in all respects as of the
              Closing Date as if made on the Closing Date and that each of
              Teleglobe's and Teleglobe Mobile's covenants and undertakings to
              be executed on or prior to the Closing Date under this Agreement
              have been executed.


                                   ARTICLE 10

                         REPRESENTATIONS AND WARRANTIES

10.1   REPRESENTATIONS AND WARRANTIES OF ORBITAL AND OCC. Each of Orbital and
       OCC hereby represents and warrants to each of ORBCOMM, Teleglobe and
       Teleglobe Mobile that:

       10.1.1 DUE INCORPORATION AND CAPACITY OF ORBITAL AND OCC. Each of Orbital
              and OCC is a corporation duly incorporated and organized, validly
              existing and in good standing under the laws of Delaware with full
              corporate power and authority to conduct its business as it is now
              conducted and to own or use the properties and assets that it
              purports to own or use. Each of Orbital and OCC has all the
              necessary rights, power and authority to enter into, execute and
              deliver this Agreement and to perform its obligations hereunder.
              The entry into, execution and delivery of this Agreement and the
              performance by each of Orbital and OCC of its obligations
              hereunder have been duly authorized and approved by all necessary
              corporate action of their respective Board of Directors.


                                       34
<PAGE>   35


       10.1.2 BINDING NATURE. This Agreement constitutes a legal, valid and
              binding obligation of Orbital and OCC enforceable against them in
              accordance with its terms.

       10.1.3 CONSENTS. Except for the consent of Orbital's lenders in
              connection with the conversion referred to in Subsection 3.3.3
              hereof, no material licenses, consents, approvals or
              authorizations of, or declaration or filing with, any governmental
              authority need to be obtained or made by Orbital or OCC as a
              condition to or in connection with the execution, delivery and
              performance by each of Orbital and OCC of this Agreement.

       10.1.4 NO VIOLATION. The execution, delivery and performance by each of
              Orbital and OCC of this Agreement do not and will not conflict
              with or result in a breach of the terms, conditions or provisions
              of, or give rise to a right of termination or constitute a default
              under, or result in any violation of, (i) any law, rule or
              regulation to which Orbital or OCC or any of their respective
              property and assets are subject, (ii) the constating documents or
              by-laws of Orbital and OCC, (iii) any resolutions of the directors
              or shareholders of Orbital or OCC, (iv) except for the consent of
              lenders in connection with the conversion referred to in
              Subsection 3.3.3 hereof, any mortgage, credit agreement or other
              material agreement or instrument to which Orbital or OCC is a
              party, (v) any order, judgement or decree binding on Orbital or
              OCC or any of their property, or (vi) any material license, waiver
              or permit currently held by Orbital or OCC. The execution,
              delivery and performance by each of Orbital and OCC of, and any
              compliance with, this Agreement will not result in the creation of
              any lien upon any of the property and assets of Orbital, OCC or
              ORBCOMM.

       10.1.5 ACTIONS PENDING. There is no action, suit or proceeding pending,
              or to the knowledge of Orbital or OCC, threatened against Orbital
              or OCC before any court, arbitrator or governmental body, agency
              or official, which (i) questions the validity of any of the
              transactions contemplated by this Agreement or (ii) would, if
              adversely determined, have a material adverse effect on the
              business, financial position or results of operations of Orbital,
              OCC or the GEMtrak Business.

       10.1.6 FCC LICENSES. OCC is the sole, true and absolute registered holder
              of the FCC Licenses and the FCC Licenses are sufficient
              authorization from the FCC for ORBCOMM to operate the ORBCOMM
              system in the United States as presently operated. Except as
              disclosed in Schedule H hereof, there is no outstanding or
              unresolved application by OCC for any FCC authorization (including
              any renewal of any FCC License). The FCC Licenses are valid and in
              full force and effect, unimpaired by any condition or restriction
              or any act or omission by Orbital or OCC which is reasonably
              likely to have a material adverse effect on ORBCOMM. Except as
              disclosed in Schedule H hereof, there are no modifications,
              amendments, applications, revocations or other proceedings pending
              or, to the knowledge of Orbital or OCC, threatened, with respect
              to the FCC Licenses (other


                                       35
<PAGE>   36


              than proceedings that apply to the telecommunications industry
              generally), and no event has occurred which, with or without the
              giving of notice or lapse of time or both, would constitute
              grounds for revocation of the FCC Licenses. Except where a lack of
              compliance is not reasonably likely to have a material adverse
              effect, since January 1, 1999 all reports required by the
              Communications Act or required to be filed with the FCC by Orbital
              or OCC have been filed and are accurate and complete in all
              material respects. Except where a lack of compliance is not
              reasonably likely to have a material adverse effect, Orbital and
              OCC have operated their business in compliance with the
              Communications Act and the rules, regulations, policies and orders
              thereunder. Orbital and OCC have not received any notice (or
              otherwise been advised) to the effect that they are in violation
              of any of such statutes, rules, regulations, policies or orders.

       10.1.7 OWNERSHIP OF ORBCOMM AND ORBCOMM USA PARTNERSHIP INTERESTS. OCC is
              the sole, true and absolute owner and registered holder of the
              ORBCOMM and ORBCOMM USA Partnership Interests described in Article
              4.1 and Article 4.3 with good and marketable title thereto, free
              and clear of any mortgage, hypothec, pledge, security interest,
              lien, charge or encumbrance or option or other rights of others
              whatsoever.

       10.1.8 GEMTRAK FINANCIAL STATEMENTS. Orbital has delivered to Teleglobe
              and ORBCOMM the unaudited balance sheet of the GEMtrak Business as
              at March 31, 1999 (the "GEMTRAK FINANCIAL STATEMENT"). The GEMtrak
              Financial Statement fairly presents the financial condition of the
              GEMtrak Business as at March 31, 1999, in accordance with United
              States generally accepted accounting principles. Except as
              disclosed in the GEMtrak Financial Statement, the GEMtrak Business
              has no undisclosed liabilities or obligations of any nature
              (whether known or unknown and whether absolute, accrued,
              contingent, or otherwise) except for current liabilities incurred
              in the ordinary course of business since the date thereof.

10.2   REPRESENTATIONS AND WARRANTIES OF TELEGLOBE AND TELEGLOBE MOBILE. Each of
       Teleglobe and Teleglobe Mobile hereby represents and warrants to each of
       ORBCOMM, Orbital and OCC that:

       10.2.1 DUE INCORPORATION OR FORMATION AND CAPACITY OF TELEGLOBE,
              TELEGLOBE MOBILE AND ORBCOMM CANADA. Teleglobe is a corporation
              duly incorporated and organized, validly existing and in good
              standing under the Canada Business Corporations Act. Teleglobe
              Mobile is a general partnership duly formed under the laws of
              Delaware. Each of Teleglobe and Teleglobe Mobile has all the
              necessary right, power and authority to enter into, execute and
              deliver this Agreement and to perform its obligations hereunder.
              The entry into, execution and delivery of this Agreement and the
              performance by each of Teleglobe and Teleglobe Mobile of its
              obligations hereunder have been duly authorized and approved by
              all necessary corporate action of the Board of Directors of,


                                       36
<PAGE>   37


              respectively, Teleglobe and Teleglobe Mobile Investment Inc.,
              Teleglobe Mobile's general partner.

       10.2.2 BINDING NATURE. This Agreement constitutes a legal, valid and
              binding obligation of Teleglobe and Teleglobe Mobile enforceable
              against them in accordance with its terms.

       10.2.3 CONSENTS. No material licenses, consents, approvals or
              authorizations of, or declaration or filing with, any governmental
              authority need to be obtained or made by Teleglobe or Teleglobe
              Mobile as a condition to or in connection with the execution,
              delivery and performance by each of Teleglobe and Teleglobe Mobile
              of this Agreement.

       10.2.4 NO VIOLATION. The execution, delivery and performance by each of
              Teleglobe and Teleglobe Mobile of this Agreement do not and will
              not conflict with or result in a breach of the terms, conditions
              or provisions of, or give rise to a right of termination or
              constitute a default under, or result in any violation of, (i) any
              law, rule or regulation to which Teleglobe or Teleglobe Mobile or
              any of their respective property and assets are subject, (ii) the
              constating documents or by-laws, as applicable, of Teleglobe and
              Teleglobe Mobile, (iii) any resolutions of the directors,
              shareholders or partners, as applicable, of Teleglobe or Teleglobe
              Mobile, (iv) any mortgage, credit agreement or other material
              agreement or instrument to which Teleglobe or Teleglobe Mobile is
              a party, (v) any order, judgement or decree binding on Teleglobe
              or Teleglobe Mobile or any of their property, or (vi) any material
              license, waiver or permit currently held by Teleglobe or Teleglobe
              Mobile. The execution, delivery and performance by each of
              Teleglobe and Teleglobe Mobile of, and any compliance with, this
              Agreement will not result in the creation of any lien upon any of
              the property and assets of Teleglobe, Teleglobe Mobile and
              ORBCOMM.

       10.2.5 ACTIONS PENDING. There is no action, suit or proceeding pending,
              or to the knowledge of Teleglobe or Teleglobe Mobile, threatened
              against Teleglobe or Teleglobe Mobile before any court, arbitrator
              or governmental body, agency or official, which (i) questions the
              validity of any of the transactions contemplated by this Agreement
              or (ii) would, if adversely determined, have a material adverse
              effect on the business, financial position or results of
              operations of Teleglobe or Teleglobe Mobile.

       10.2.6 ORBCOMM AND ORBCOMM INTERNATIONAL PARTNERSHIP INTERESTS. Teleglobe
              Mobile is the sole, true and absolute owner and registered holder
              of the ORBCOMM and ORBCOMM International Partnership Interests
              described in Article 4.1 and Article 4.4 with good and marketable
              title thereto, free and clear of any mortgage, hypothec, pledge,
              security interest, lien, charge or encumbrance or option or other
              rights of others whatsoever.


                                       37
<PAGE>   38


       10.2.7 ORBCOMM CANADA FINANCIAL STATEMENTS. Teleglobe has delivered to
              Orbital and ORBCOMM the unaudited balance sheet of ORBCOMM Canada
              as at December 31 in each of the years 1996 through 1998, and the
              related unaudited statement of income, changes in stockholders'
              equity, and cash flow for each of the fiscal years then ended (the
              "ORBCOMM CANADA FINANCIAL STATEMENTS"). The ORBCOMM Canada
              Financial Statements fairly present the financial condition and
              the results of operations, changes in stockholders' equity, and
              cash flow of ORBCOMM Canada as at the respective dates of and for
              the periods referred to in such financial statements, all in
              accordance with Canadian generally accepted accounting principles,
              and the ORBCOMM Canada Financial Statements reflect the consistent
              application of such accounting principles throughout the periods
              involved. Except as disclosed in the ORBCOMM Canada Financial
              Statements, ORBCOMM Canada has no undisclosed liabilities or
              obligations of any nature (whether known or unknown and whether
              absolute, accrued, contingent, or otherwise) except for current
              liabilities incurred in the ordinary course of business since the
              respective dates thereof.


                                   ARTICLE 11

                                 INDEMNIFICATION

11.1   For the purposes of any claim alleging that one of the representations or
       warranties contained herein is false or incorrect on the date hereof or
       on the Closing Date, the rights ensuing from these representations and
       warranties shall continue to have effect for a period of two years after
       the date hereof notwithstanding any inspection, inquiry and verification
       made by any Party or on its behalf.

11.2   If a representation or warranty of any Party is false or incorrect, such
       Party and any Indemnifying Party (as defined below), on prior written
       notice from any other Party, agrees to undertake the requisite measures
       within 30 days from receipt of such notice to remedy the default. For the
       purpose of Article 11, the Party whose representation or warranty is
       false or incorrect is referred to as the "INDEMNIFYING PARTY" and the
       other Parties are referred to as the "INDEMNIFIED PARTIES".

11.3   The Indemnifying Party undertakes to indemnify the Indemnified Parties,
       jointly and severally with any other Indemnifying Party, for the amount
       of the damages (which shall include all losses, damages, liabilities,
       reasonable costs and expenses (including, without limitation, all
       reasonable legal and other professional fees and disbursements, interest,
       penalties and amounts paid in settlement)) sustained by the Indemnified
       Parties as a result of or arising directly out of or in connection with
       any breach or inaccuracy of any representation or warranty of an
       Indemnifying Party contained in this Agreement, provided that:


                                       38
<PAGE>   39


       11.3.1 an Indemnifying Party shall not be required to indemnify or save
              harmless the Indemnified Parties in respect of any breach or
              inaccuracy of a representation or warranty unless (i) one of the
              Indemnified Parties shall have provided notice to the Indemnifying
              Party of such breach or inaccuracy, and (ii) such breach or
              inaccuracy shall not have been remedied by an Indemnifying Party
              in accordance with Section 11.2 to the satisfaction of the
              Indemnified Parties acting reasonably, provided, however, that all
              damages sustained by the Indemnified Parties as a result of or
              arising directly out of or in connection with any breach or
              inaccuracy of any representation or warranty of an Indemnifying
              Party contained in this Agreement during the period prior to such
              remedy shall be subject to the indemnification provisions of
              Section 11.3;

       11.3.2 if a third party files a claim against an Indemnified Party and
              this claim is likely to entail falsity or inaccuracy in one or
              another of the representations and warranties given by an
              Indemnifying Party, the latter shall have the right, at its
              expense, to participate in or assume control of the negotiations,
              settlement or contestation of the third-party claim. In such case,
              the Indemnifying Party shall reimburse the Indemnified Parties for
              all reasonable costs and expenses the latter shall incur because
              of such contestation. If the Indemnifying Party opts to assume
              control of the matter, the Indemnified Parties must co-operate
              with it, may participate in the negotiation, settlement or
              contestation of the third-party claims and shall have the right to
              choose together with the Indemnifying Party the attorney
              responsible for contesting this claim.

11.4   The amount of the indemnification for any damages which the Indemnified
       Parties shall be entitled to receive pursuant to this Agreement shall be
       payable within 30 days following the 30-day period contemplated in
       Section 11.2 and shall be determined after giving effect to (i) the
       provisions of Section 11.3, (ii) tax savings and (iii) recoveries from
       third parties.


                                   ARTICLE 12

                                  MISCELLANEOUS

12.1   SUCCESSORS AND ASSIGNS. This Agreement and the rights and obligations set
       forth herein shall not be assignable by the Parties. The provisions of
       this Agreement shall, except as otherwise provided herein, enure to the
       benefit of and be binding upon the Parties and their respective heirs,
       executors, administrators and successors and each and every Person so
       bound shall make, execute and deliver all documents necessary to carry
       out this Agreement.

12.2   EXPENSES. Except as otherwise specifically provided herein, each Party
       shall bear and be responsible for all of its costs and expenses,
       including financial advisory and legal fees and disbursements, incurred
       in connection with this Agreement and the transactions hereby
       contemplated.


                                       39
<PAGE>   40


12.3   PUBLIC ANNOUNCEMENT. Except as provided herein or as required by law, no
       press release related to this Agreement or the transactions contemplated
       herein shall be issued without the joint approval of Teleglobe and
       Orbital.

12.4   ENTIRE AGREEMENT. Except for the other Definitive Agreements, as amended
       pursuant to the terms hereof, this Agreement constitutes the entire
       agreement between the Parties with respect to the subject matter hereof
       and the transactions herein contemplated and replaces all previous
       agreements and understandings, if any, between the Parties with respect
       to the subject matter hereof and the transactions contemplated herein.

12.5   RESOLUTION OF DISPUTES. Any controversy or claim that may arise under,
       out of or in connection with or relating to this Agreement or any breach
       hereof shall be settled in accordance with the terms of Article 13.4 of
       the Master Agreement.

12.6   NOTICES. All notices, consents, waivers, and other communications under
       this Agreement must be in writing and will be deemed to have been duly
       given when (i) delivered by hand (with written confirmation of receipt),
       (ii) sent by telecopier (with written confirmation of receipt), or (iii)
       when received by the addressee, if sent by a nationally recognized
       overnight delivery service (receipt requested), in each case to the
       appropriate addresses and telecopier numbers set forth below:

       If to Orbital or OCC:

       Orbital Sciences Corporation
       21700 Atlantic Boulevard
       Dulles, Virginia
       20166-6801
       Fax: 703.406.3502

       Attention: Executive Vice President and Chief Financial Officer

       If to Teleglobe or Teleglobe Mobile:

       Teleglobe Inc.
       1000 de La Gauchetiere Street West
       Montreal, Quebec
       H3B 4X5
       Fax: 514.868.7438

       Attention:  Vice President, Chief Legal Officer and Corporate Secretary


                                       40
<PAGE>   41


       If to ORBCOMM:

       ORBCOMM Global, L.P.
       2455 Horse Pen Road
       Herndon, Virginia
       20171-3426
       Fax: 703.406.5933

       Attention: Senior Vice President and General Counsel

       Notice of change of address may be given by any Party in the same manner.

12.7   FURTHER ASSURANCES. Each Party shall do such acts and shall execute such
       further documents, conveyances, deeds, assignments, transfers and the
       like, and will cause the doing of such acts and will cause the execution
       of such further documents as are within its power as any other Party may
       in writing at any time and from time to time reasonably request be done
       or executed, in order to give full effect to the provisions of this
       Agreement.

12.8   INDENTURE. Should the consummation or implementation of any of the
       agreements provided herein result in a breach of the terms of the
       Indenture, the Parties agree to negotiate in good faith a modification to
       any such agreement so that the intended result of such agreement will be
       attained without breaching the terms of the Indenture.

12.9   TIME OF ESSENCE. Time shall be of the essence of this Agreement.

12.10  COUNTERPARTS. This Agreement may be executed in one or more counterparts
       each of which when so executed shall be deemed to be an original and such
       counterparts together shall constitute but one of the same instrument.

    [remainder of page intentionally left blank -- signature page to follow]


                                       41
<PAGE>   42


IN WITNESS WHEREOF the Parties have executed this Agreement as of the date set
out above.


                                       ORBITAL SCIENCES CORPORATION

                                       Per:
                                           ---------------------------------


                                       ORBITAL COMMUNICATIONS CORPORATION

                                       Per:
                                           ---------------------------------


                                       TELEGLOBE INC.

                                       Per:
                                           ---------------------------------
                                           Andre Bourbonnais
                                           Vice President, Chief Legal Officer
                                           and Corporate Secretary

                                       TELEGLOBE MOBILE PARTNERS
                                       by its General Partner
                                       TELEGLOBE MOBILE INVESTMENT INC.

                                       Per:
                                           ---------------------------------
                                           Andre Bourbonnais
                                           President

                                       ORBCOMM GLOBAL, L.P.

                                       Per:
                                           ---------------------------------
                                           Scott Webster
                                           President and Chief Executive Officer



                                       42

<PAGE>   1
                                                                    EXHIBIT 99.1

PRESS RELEASE                                     EMBARGO UNTIL JANUARY 27, 2000
                                                                    AT 7:00 A.M.

           TELEGLOBE AND ORBITAL STRENGTHEN COMMITMENT TO ORBCOMM WITH
                     NEW OWNERSHIP AND FINANCING AGREEMENT

   ORBCOMM PARTNERS AGREE TO PROVIDE NEW EQUITY TO FUND ORBCOMM'S OPERATIONS
                     AND IMPROVE ITS FINANCIAL FLEXIBILITY

(MONTREAL, QC AND DULLES, VA, JANUARY 27, 2000) - Teleglobe Inc. (NYSE, TSE:
TGO) and Orbital Sciences Corporation (NYSE: ORB) announced today that they have
agreed to restructure their partnership governing the financing and ownership of
ORBCOMM Global, L.P. (ORBCOMM), the world's first commercial provider of global
wireless data communications services through a network of 35 satellites
operating in low-Earth orbit.

As a result of this agreement and previous capital infusions, ORBCOMM's equity
will increase by over US$100 million, mostly due to the conversion of certain
payables to Orbital and Teleglobe. Also as a result of this agreement, which has
been approved by the companies' respective Boards of Directors, Teleglobe
becomes the majority owner and sole general partner of ORBCOMM.

"This agreement enables ORBCOMM to continue its rapid growth and capitalize on
the market leadership it has established at a time when significant progress is
being made in a significant number of industry segments worldwide. As a
strategic investor, Teleglobe intends to continue to provide equity financing to
ORBCOMM, which is also actively pursuing opportunities for third party equity in
the partnership," said Claude Seguin, Executive Vice President, Finance, and
Chief Financial Officer of Teleglobe. "While Teleglobe maintains its focus on
its Internet strategy and GlobeSystem investment, we believe this agreement will
allow Teleglobe to enhance the value of its investment in ORBCOMM," added Mr.
Seguin.

Mr. David W. Thompson, Orbital's Chairman and Chief Executive Officer, said,
"Orbital has been, and will continue to be, fully committed to the success of
ORBCOMM. We will continue to actively participate in ORBCOMM's business
activities, but without the need for further capital investments on our part if
we so choose. Through this agreement, we are carrying out our long-standing
strategy of maintaining a very significant ownership stake in the high-growth
and high-margin potential of ORBCOMM and our other satellite services ventures,
such as ORBIMAGE and ORBNAV. Our equity position in ORBCOMM and these other
start-up companies is complemented by our space and ground infrastructure and
satellite access products sectors that provide us with growing revenues and
earnings. By eliminating our share of the future capital requirements for
ORBCOMM, this agreement significantly eases our cash needs as we aim to generate
improved financial results in 2000," added Mr. Thompson. "I am delighted by the
partners' continuing commitment to ORBCOMM and the enhanced strength of the
business as a result of this agreement. We believe this agreement enables us to
accelerate our growth and deliver on the growing market demand for ORBCOMM
services," said Mr. Scott L. Webster, Chairman and Chief Executive Officer of
ORBCOMM.

ORBCOMM provides two-way monitoring, tracking and messaging services through the
world's first commercial low-Earth orbit satellite-based data communications
system. ORBCOMM applications include tracking of mobile assets such as trailers,
containers, rail cars, heavy equipment, fishing vessels, barges and government
assets; monitoring of fixed assets such as


<PAGE>   2


electric utility meters, oil and gas storage tanks, wells and pipelines and
environmental projects; and messaging services for consumers and commercial and
government entities. For more information, visit www.orbcomm.com.

Teleglobe is a leading global provider of broadband services with the most
extensive global Internet network. Delivering advanced broadband applications to
customers in more than 100 countries - matching global reach with global depth -
Teleglobe is the premier communications architecture for the digital economy.
Teleglobe is currently enhancing its leadership position through
GLOBESYSTEM(TM), a 5 year, US$5 billion strategic initiative providing 160
cities around the world with scalable broadband service platforms, and linking
them through a seamless data network. GLOBESYSTEM is the world's first globally
integrated Internet, voice, data and video network. For more information, visit
www.teleglobe.com.

Orbital is one of the largest space technology and satellite services companies
in the world, with 1999 revenues targeted to exceed $900 million. The company,
which is headquartered in Dulles, Virginia, employs over 5,200 people at its
major facilities in the United States, Canada and several overseas locations.
Orbital is the world's leading manufacturer of low-cost space systems and
products, including satellites, launch vehicles, electronics and sensors,
satellite ground systems and software, and satellite-based navigation and
communications products. Through its ORBCOMM and ORBIMAGE affiliates and ORBNAV
subsidiary, Orbital is also a pioneering operator of satellite-based networks
that provide data communications, high-resolution imagery and automotive
information services to customers around the world. For more information, visit
http://www.orbital.com.

For more information:

<TABLE>
<CAPTION>
TELEGLOBE INC.                               ORBITAL SCIENCES CORPORATION
<S>                                          <C>

Michele Beaubien                             Barron Beneski
Vice President, Corporate Communications     Vice President, Corporate Communications
Tel. 514-868-7762                            Tel. 703-406-5528
Email. [email protected]        Email. [email protected]

Nicole Blanchard                             Tim Perrott
Director, Investor Relations                 Vice President of Investor Relations
Tel. 514-868-8148                            Tel. 703-406-5997
Email. [email protected]        Email. [email protected]
</TABLE>



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