Document:

EXHIBIT 10.44

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

                           FIRST AMENDED AND RESTATED

                       LIMITED LIABILITY COMPANY AGREEMENT

                                       OF

                         MOTIENT SATELLITE VENTURES LLC

                                  June 29, 2000

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

<PAGE>

                                TABLE OF CONTENTS

                                                                            Page

ARTICLE I DEFINED TERMS........................................................1

     Section 1.1      Definitions..............................................1
     Section 1.2      Headings.................................................8
     Section 1.3      Interpretation...........................................8

ARTICLE II CONTINUATION AND TERM...............................................8

     Section 2.1      Continuation.............................................8
     Section 2.2      Name.....................................................9
     Section 2.3      Term.....................................................9
     Section 2.4      Registered Agent and Office..............................9
     Section 2.5      Principal Place of Business..............................9
     Section 2.6      Qualification in Other Jurisdictions.....................9
     Section 2.7      Agreement................................................9

ARTICLE III PURPOSE AND POWERS OF THE COMPANY.................................10

     Section 3.1      Purpose.................................................10
     Section 3.2      Powers of the Company...................................10
     Section 3.3      Limitations on Company Powers...........................10

ARTICLE IV CAPITAL CONTRIBUTIONS AND CAPITAL ACCOUNTS.........................10

     Section 4.1      Capital Contributions...................................10
     Section 4.2      Status of Capital Contributions.........................11
     Section 4.3      Membership Interest.....................................11
     Section 4.4      Capital Accounts........................................11

ARTICLE V MEMBERS.............................................................12

     Section 5.1      Powers of Members.......................................12
     Section 5.2      Consent of Members......................................12
     Section 5.3      Actions of the Members..................................14
     Section 5.4      Partition...............................................14
     Section 5.5      Resignation.............................................14

ARTICLE VI MANAGEMENT 15

     Section 6.1      The Board of Directors..................................15
     Section 6.2      Officers................................................20

ARTICLE VII ALLOCATIONS.......................................................22

     Section 7.1      Profits and Losses......................................22
     Section 7.2      Special Allocations.....................................23
     Section 7.3      Allocation Rules........................................25

                                       ii

<PAGE>

     Section 7.4      Section 704(c) of the Code..............................25
     Section 7.5      Uncertainties in Allocations and Distributions..........26

ARTICLE VIII DISTRIBUTIONS....................................................26

     Section 8.1      Distributions...........................................26
     Section 8.2      Distributions to Pay Taxes..............................26
     Section 8.3      Dissolution.............................................26
     Section 8.4      Withholding Taxes.......................................27
     Section 8.5      Limitations on Distribution.............................27
     Section 8.6      Capital Proceeds........................................27

ARTICLE IX ADDITIONAL ISSUANCES, TRANSFERS, ADMISSION
     OF MEMBERS AND CONVERSION................................................28

     Section 9.1      Additional Issuances of Interests.......................28
     Section 9.2      Transfers...............................................29
     Section 9.3      Admission of Substituted Members........................33
     Section 9.4      Admission of Additional Members.........................33
     Section 9.5      Conversion; Drag Along Rights...........................34
     Section 9.6      Company Registration Rights.............................35

ARTICLE X BOOKS AND RECORDS...................................................35

     Section 10.1     Books, Records and Financial Statements.................35
     Section 10.2     Accounting Method.......................................36
     Section 10.3     Audit...................................................36

ARTICLE XI TAX MATTERS........................................................36

     Section 11.1     Tax Matters Partner.....................................36
     Section 11.2     Section 754 Election....................................37
     Section 11.3     Taxation as Partnership.................................37

ARTICLE XII LIABILITY, EXCULPATION AND INDEMNIFICATION........................37

     Section 12.1     Liability...............................................37
     Section 12.2     Exculpation.............................................37
     Section 12.3     Indemnification.........................................38
     Section 12.4     Expenses................................................38
     Section 12.5     Insurance...............................................39
     Section 12.6     Outside Businesses......................................39

ARTICLE XIII DISSOLUTION, LIQUIDATION AND TERMINATION.........................39

     Section 13.1     Dissolution.............................................39
     Section 13.2     Notice of Dissolution...................................40
     Section 13.3     Liquidation.............................................40
     Section 13.4     Termination.............................................40
     Section 13.5     Claims of the Members...................................40

                                      iii

<PAGE>

ARTICLE XIV AMENDMENTS........................................................41

     Section 14.1     Amendments..............................................41

ARTICLE XV MISCELLANEOUS......................................................41

     Section 15.1     Further Assurances......................................41
     Section 15.2     Notices.................................................41
     Section 15.3     Failure to Pursue Remedies..............................42
     Section 15.4     Cumulative Remedies.....................................42
     Section 15.5     Binding Effect..........................................42
     Section 15.6     Severability............................................42
     Section 15.7     Counterparts............................................42
     Section 15.8     Integration.............................................42
     Section 15.9     Governing Law...........................................43

<PAGE>

                           FIRST AMENDED AND RESTATED

                       LIMITED LIABILITY COMPANY AGREEMENT

                                       OF

                         MOTIENT SATELLITE VENTURES LLC

                  THIS FIRST  AMENDED AND  RESTATED  LIMITED  LIABILITY  COMPANY
AGREEMENT OF MOTIENT SATELLITE VENTURES LLC (the "Company") dated as of June 29,
2000 is  entered  into by and among the  Persons  listed  on  Schedule  I hereto
(individually,  a  "Member",  and  collectively,  together  with any  additional
Members hereafter admitted to the Company in accordance with this Agreement, the
"Members").

                  WHEREAS,  Motient, as sole Member,  formed a limited liability
company pursuant to the Delaware Limited Liability  Company Act (6 Del. C. Sect.
8-101,  et seq.) by filing a Certificate of Formation on June 16, 2000 with the
Secretary  of State of Delaware and entering  into a limited  liability  company
agreement dated as of June 16, 2000 (the "Original Agreement"); and

                  WHEREAS,  the parties  hereto  desire to amend and restate the
Original  Agreement in its entirety and to continue the existence of the Company
on the terms set forth in this Agreement;

                  NOW,  THEREFORE,   in  consideration  of  the  agreements  and
obligations set forth herein and for other good and valuable consideration,  the
receipt and  sufficiency  of which are hereby  acknowledged,  the Members hereby
agree as follows:

ARTICLE I

                                  DEFINED TERMS

Section  1.1  Definitions.  Unless the  context  otherwise  requires,  the terms
defined in this Article I shall,  for the purposes of this  Agreement,  have the
meanings herein specified.

                  "Additional  Member" means a Person admitted to the Company as
a Member pursuant to Section 9.4.

                  "Adjusted  Capital Account" means, with respect to any Member,
the balance in such Member's Capital  Account,  increased by such Member's share
of the Minimum Gain and "partner  nonrecourse  debt minimum gain" (as defined in
Treasury Regulations Section 1.704-2(i)(2))

                  "Adjusted  Capital Account Deficit" means, with respect to any
Member, the deficit balance,  if any, in such Member's Capital Account as of the
end  of  the  relevant  Fiscal  Year,  after  giving  effect  to  the  following
adjustments:

                  (i) Credit to such  Capital  Account  any  amounts  which such

         Member is  obligated to restore or is deemed to be obligated to restore
         pursuant to  the penultimate sentences of Treasury Regulations Sections
         1.704-2(g)(1) and 1.704-2(i)(5); and

                  (ii) Debit to such  Capital  Account  the items  described  in
         Treasury Regulations Sections 1.704-1(b)(2)(ii)(d)(4), (5) and (6).

The foregoing  definition  of Adjusted  Capital  Account  Deficit is intended to
comply with the provisions of Treasury Regulations Sections 1.704-1(b)(2)(ii)(d)
and shall be interpreted consistently therewith.

                  "Affiliate"  means with  respect to a  specified  Person,  any
Person that  directly or  indirectly  controls,  is  controlled  by, or is under
common control with, the specified Person. As used in this definition,  the term
"control" means the possession,  directly or indirectly,  of the power to direct
or cause the  direction  of the  management  and  policies of a Person,  whether
through ownership of voting securities, by contract or otherwise.

                  "Agreement"  means this Limited Liability Company Agreement of
the Company, as amended, modified, supplemented or restated from time to time.

                  "Ancillary  Agreements"  has  the  meaning  set  forth  in the
Investment Agreement.

                  "Asset Sale Agreement" means the Asset Sale Agreement dated as
of June 29, 2000 between the Company and Services.

                  "Bankruptcy"  means,  with respect to any Person,  such Person
shall  generally  not pay its debts as such debts  become due, or shall admit in
writing  its  inability  to pay its  debts  generally,  or shall  make a general
assignment for the benefit of creditors,  or any proceeding  shall be instituted
by or against such Person  seeking to adjudicate it a bankrupt or insolvent,  or
seeking  liquidation,  winding  up,  reorganization,   arrangement,  adjustment,
protection,  relief, or composition of it or its debts under any law relating to
bankruptcy,  insolvency or reorganization  or relief of debtors,  or seeking the
entry  of an  order  for  relief  or the  appointment  of a  receiver,  trustee,
custodian or other similar  official for it or for any  substantial  part of its
property and, in the case of any such proceeding  instituted against it (but not
instituted by it), either such proceeding  shall remain  undismissed or unstayed
for a period of sixty (60) days, or any of the actions sought in such proceeding
(including, without limitation, the entry of an order for relief against, or the
appointment of a receiver,  trustee, custodian or other similar official for it,
or for any  substantial  part of its property) shall occur; or such Person shall
take any action to authorize any of the actions set forth above.

                  "Board" has the meaning set forth in Section 6.1.

                  "Business  Day" means a day of the year on which banks are not
required or authorized to close in New York City.

                  "Capital  Account"  means,  with  respect to any  Member,  the
account  maintained for such Member in accordance with the provisions of Section
4.4 hereof.

                  "Capital  Contribution" means, with respect to any Member, the
aggregate  contributions  made to the Company  pursuant to Section 4.1 hereof by
such  Member with  respect to the  Membership  Interest  in the Company  held or
purchased by such Member.

                  "Capital Event" means, a sale, transfer,  refinancing or other
disposition  of the assets of the Company  other than in the ordinary  course of
the Company's business.

                  "Capital Proceeds" means, the proceeds received by the Company
from the sale,  transfer,  refinancing or other disposition of the assets of the
Company  other  than  in the  ordinary  course  of the  Company's  business  but
excluding  any amounts  reasonably  determined  by the Board to be  necessary to
provide  a   reasonable   reserve  for   working-capital   needs  or  any  other
contingencies of the Company.

                  "Certificate of Formation"  means the Certificate of Formation
of the Company and any and all amendments thereto and restatements thereof filed
on behalf of the Company with the office of the  Secretary of State of the State
of Delaware pursuant to the Delaware Act.

                  "Chairman" has the meaning set forth in Section 6.2.

                  "Code"  means the Internal  Revenue  Code of 1986,  as amended
from time to time, or any  corresponding  federal tax statute  enacted after the
date of this Agreement. A reference to a specific section of the Code refers not
only to such  specific  section but also to any  corresponding  provision of any
federal tax statute enacted after the date of this  Agreement,  as such specific
section or  corresponding  provision is in effect on the date of  application of
the provisions of this Agreement containing such reference.

                  "Columbia  Investor Group"  means the Investor Group initially
consisting of Columbia Space (QP), Inc.,  Columbia Space (AI), Inc. and Columbia
Space Partners, Inc.

                  "Common  Unit"  means,  as of the  date  of  determination,  a
Percentage Interest equal to (x) 100% minus the Percentage Interest  represented
by all  Investor  Units  outstanding  as of such date,  divided by (y) the total
number of Common Units outstanding as of such date of such determination.

                  "Company"  means  Motient  Satellite  Ventures LLC, a Delaware
limited liability company.

                  "Covered  Person" means any Member,  any Affiliate of a Member
or any officers, directors, shareholders,  partners, employees,  representatives
or  agents  of a  Member  or  their  respective  Affiliates,  or  any  officers,
directors, shareholders,  partners, employees,  representatives or agents of the
Company or its Affiliates or any liquidating trustee under Section 13.3.

                  "Delaware Act" means the Delaware  Limited  Liability  Company
Act, 6 Del. C.Sect.18-101, et seq., as amended from time to time.

                  "Depreciation" means, for each Fiscal Year or other period, an
amount equal to the depreciation,  amortization or other cost recovery deduction
allowable  with  respect  to an asset  for  such  Fiscal  Year or other  period;
provided,  however,  that if the Gross Asset Value of an asset  differs from its
adjusted  basis for federal  income tax purposes at the beginning of such Fiscal
Year or other period,  Depreciation shall be an amount that bears the same ratio
to such  beginning  Gross Asset Value as the  federal  income tax  depreciation,
amortization  or other cost  recovery  deduction  with respect to such asset for
such Fiscal Year or other period bears to such beginning adjusted tax basis; and
provided further,  that if the federal income tax depreciation,  amortization or
other cost  recovery  deduction  for such Fiscal  Year or other  period is zero,
Depreciation  shall be determined  with reference to such beginning  Gross Asset
Value using any reasonable method selected by the Board.

                  "Excluded  Securities"  means any interests in the Company (a)
issued  pursuant  to the  Investment  Agreement  and  any  of  the  transactions
contemplated  thereby,  (b) issued in  connection  with the  acquisition  of the
business of another entity, whether by the purchase of equity securities, assets
or  otherwise,  (c)  issued  as part of an  Initial  Public  Offering  or  other
registered  underwritten  public  offering of the  Company's  securities  or (d)
issued under an employee compensation plan approved by the Board.

                  "Family  Member"  means,  with  respect  to any Person (i) the
spouse,  parents,  children,  siblings,  mother  and  father-in-law,   sons  and
daughters-in-law and brothers and sisters-in-law of such Person or of any of the
beneficial owners of such Person,  (ii) any trust whose beneficiaries are one or
more of such Person and such  persons or (iii) any  partnership  or other entity
whose owners are one or more of such Person and such persons.

                  "Fiscal  Year"  means  (i)  the  period  commencing  upon  the
formation of the Company and ending on December 31,  2000,  (ii) any  subsequent
twelve (12) month period  commencing  on January 1 and ending on December 31, or
(iii) any portion of the period  described  in clause (ii) of this  sentence for
which the Company is required  to  allocate  Profits,  Losses and other items of
Company income, gain, loss or deduction pursuant to Article VII hereof.

                  "Gross Asset  Value"  means,  with respect to any asset,  such
asset's adjusted basis for federal income tax purposes, except as follows:

               (i) the initial Gross Asset Value of any asset  contributed  by a
          Member to the  Company  shall be the gross fair  market  value of such
          asset, as agreed to by the contributing Member and the Board;

               (ii)  the  Gross  Asset  Value  of all  Company  assets  shall be
          adjusted  to equal  their  respective  gross fair  market  values,  as
          determined  by  the  Board,  as  of  the  following   times:  (a)  the
          acquisition  of an  additional  interest  in the Company by any new or
          existing Member or any other adjustment in the Percentage Interests of
          the Members;  (b) the  distribution by the Company to a Member of more
          than a de minimis amount of Company assets as  consideration  for such
          Member's Membership  Interest;  and (c) the liquidation of the Company
          within    the    meaning    of    Treasury     Regulations     Section
          1.704-1(b)(2)(ii)(g);  provided, however, that adjustments pursuant to
          subclauses  (a) and (b) of this  sentence  shall  be made  only if the
          Board  reasonably  determines  that such  adjustments are necessary or
          appropriate to reflect the relative economic  interests of the Members
          in the Company;  and provided  further,  that upon the exercise of the
          Investor  Option there shall be no adjustment to the Gross Asset Value
          of the Company's assets; and

               (iii) the Gross Asset Value of any Company asset  distributed  to
          any Member  shall be the gross fair market  value of such asset on the
          date of distribution, as determined by the Board.

If the Gross Asset Value of an asset has been determined or adjusted pursuant to
clause (i) or (ii) above, such Gross Asset Value shall thereafter be adjusted by
the  Depreciation  taken into account with respect to such asset for purposes of
computing Profits and Losses.

                  "Initial  Capital  Contribution"  means,  with  respect to any
Member, such Member's Capital Contribution on the date hereof.

                  "Initial  Public   Offering"  means  the  closing  of  a  firm
commitment  underwritten  public offering of equity  interests in the Company or
its successor.

                  "Investment Agreement" means the Investment Agreement dated as
of June 22, 2000 among the Company, Motient and the Investors.

                  "Investors"  means each Member  listed on the  signature  page
hereof as an Investor,  each other Person admitted as an Investor after the date
hereof and,  subject to Section 9.2(i),  any Person acquiring all or part of the
Membership  Interest  of an  Investor  that is  admitted as a Member as provided
herein.

                  "Investor  Directors" means directors elected by the Investors
pursuant to Section 6.1(c).

                  "Investor  Group" has the meaning set forth in the  Investment
Agreement.

                  "Investor  Group  Designee"  has the  meaning set forth in the
Investment Agreement.

                  "Investor  Option" has the meaning set forth in the Investment
Agreement.

                  "Investor  Option  Closing"  has the  meaning set forth in the
Investment Agreement.

                  "Investor Unit"  means,  at  all times,  and for each Investor
Unit, a Percentage  Interest equal to 1%.

                  "IP Assets" means the Motient  Derivative  Works and the Newco
Technology and all Intellectual Property Rights associated with each of them (as
each such capitalized term is defined in the Research and Development Agreement)
and the rights in the Motient  Technology  granted under the license  granted to
Newco pursuant to Section 8.4 of the Research and  Development  Agreement to the
extent actually contained in any Motient Derivative Works.

                  "Member" has the meaning set forth in the opening paragraph of
this Agreement.

                  "Membership Interest" means a Member's aggregate rights in the
Company in accordance  with this  Agreement and the Delaware Act,  including the
Member's  right to share in the  Profits  and Losses of the Company and right to
receive distributions of the Company's assets.

                  "Minimum   Gain"  has  the   meaning  set  forth  in  Treasury
Regulations Sections 1.704-2(b)(2) and 1.704-2(d).

                  "Motient" means Motient Corporation, a Delaware corporation.

                  "Motient  Directors"  means the  directors  elected by Motient
pursuant to Section 6.1(c).

                  "Percentage  Interest"  means the percentage  interest used in
determining  voting,  allocation,  distribution and other rights as set forth in
this  Agreement  and,  with  respect  to each  Member,  shall be  calculated  by
reference  to the  number  of  Units  held  by  such  Member  as of the  date of
determination  and shall be reflected on Schedule I in  accordance  with Section
2.1(c).

                  "Person"  means  any  individual,  corporation,   association,
partnership  (general  or  limited),   joint  venture,  trust,  estate,  limited
liability company, or other legal entity or organization.

                  "President" has the meaning set forth in Section 6.2.

                  "Profits" and "Losses"  means,  for each Fiscal Year an amount
equal to the Company's  taxable income or loss for such Fiscal Year,  determined
in accordance  with Section  703(a) of the Code (but including in taxable income
or loss, 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),  with the
following adjustments:

               (i) any income of the Company  exempt from federal income tax and
          not  otherwise  taken  into  account  in  computing  Profits or Losses
          pursuant to this  definition  shall be added to such taxable income or
          loss;

               (ii)  any  expenditures  of  the  Company  described  in  Section
          705(a)(2)(B)  of the Code (or  treated as  expenditures  described  in
          Section  705(a)(2)(B)  of the Code  pursuant to  Treasury  Regulations
          Section  1.704-1(b)(2)(iv)(i)) and not otherwise taken into account in
          computing  Profits  or Losses  pursuant  to this  definition  shall be
          subtracted from such taxable income or loss;

               (iii) in the event the Gross Asset Value of any Company  asset is
          adjusted in accordance  with clause (ii) or (iii) of the definition of
          "Gross  Asset Value"  above,  the amount of such  adjustment  shall be
          taken into account as gain or loss from the  disposition of such asset
          for purposes of computing Profits or Losses;

               (iv) gain or loss resulting from any  disposition of any asset of
          the  Company  with  respect  to which gain or loss is  recognized  for
          federal  income tax  purposes  shall be computed by  reference  to the
          Gross Asset Value of the asset disposed of,  notwithstanding  that the
          adjusted  tax basis of such asset  differs from its Gross Asset Value;
          and

                  (v) in lieu of the  depreciation,  amortization and other cost
         recovery deductions taken into account in computing such taxable income
         or loss, there shall be taken into account Depreciation for such Fiscal
         Year or other  period,  computed in accordance  with the  definition of
         "Depreciation" above.

                   "Required  Investor  Majority" means  Investors  holding more
than sixty percent (60%) of the Percentage Interests held by all Investors as of
the date of determination.

                  "Research and Development Agreement" has the meaning set forth
in the Investment Agreement.

                  "Restriction  Termination  Date" has the  meaning set forth in
Section 9.2.

                  "Secretary" has the meaning set forth in Section 6.2.

                  "Services" means Motient Services Inc., a Delaware corporation
and  wholly-owned  subsidiary of Motient.

                  "Spectrum Investor Group"  means  the Investor Group initially
consisting  of Spectrum  Space  Equity  Investors  IV, Inc.,  Spectrum  Space IV
Parallel, Inc., and Spectrum Space IV Managers, Inc.

                  "Subsequent Capital  Contribution"  means, with respect to any
Member,  the  aggregate  Capital  Contributions  of such Member in excess of its
Initial Capital Contribution.

                  "Tax  Matters  Partner"  has the  meaning set forth in Section
11.1.

                  "Treasurer" has the meaning set forth in Section 6.2.

                  "Treasury  Regulations"  means  the  income  tax  regulations,
including temporary regulations, promulgated under the Code, as such regulations
may be  amended  from  time  to  time  (including  corresponding  provisions  of
succeeding regulations).

                  "Units" means Common Units and Investor Units.

                  "Unreturned Initial Capital  Contribution" means, with respect
to any Member, the excess, if any, of such Member's Initial Capital Contribution
over the cumulative distributions to such Member pursuant to Sections 8.6(a) and
13.3(ii) hereof.

                  "Unreturned  Subsequent  Capital  Contributions"  means,  with
respect to any Member,  the excess, if any, of such Member's  Subsequent Capital
Contributions  over the  cumulative  distributions  to such  Member  pursuant to
Sections 8.6(b) and 13.3(iii) hereof.

Section 1.2  Headings.  The  headings  and  subheadings  in this  Agreement  are
included for convenience and  identification  only and are in no way intended to
describe,  interpret,  define  or limit  the  scope,  extent  or  intent of this
Agreement or any provision hereof.

Section 1.3 Interpretation. Throughout this Agreement, nouns, pronouns and verbs
shall be construed as masculine, feminine, neuter, singular or plural, whichever
shall be applicable. All references herein to "Articles", "Sections" and clauses
shall refer to  corresponding  provisions of this  Agreement,  unless  otherwise
specified.

ARTICLE II

                              CONTINUATION AND TERM

Section 2.1       Continuation.

(a) The Company shall continue as a limited liability company under and pursuant
to the  provisions  of the Delaware  Act and the Members  agree that the rights,
duties and  liabilities of the Members shall be as provided in the Delaware Act,
except as otherwise provided herein.

(b) Simultaneously  with the execution of this Agreement,  the Persons listed on
Schedule I hereto  shall be  admitted  as Members  of the  Company  and shall be
issued the number and class of Units, and the Percentage  Interests  represented
thereby, listed opposite such Person's name on such Schedule I.

(c) The name and mailing  address of each Member,  the number and class of Units
issued to such Member, the Percentage  Interests  represented  thereby,  and the
amount  contributed to the capital of the Company by such Member shall be listed
on Schedule I attached hereto.  The Company shall update Schedule I from time to
time as necessary  to  accurately  reflect the  information  therein,  including
updates to reflect new  issuances of  Membership  Interests or  assignments  and
transfers of all or any part of a Member's Membership Interest, in each case, in
accordance  with this  Agreement and indicating the name and address of such new
Member,  transferee  or  assignee  along  with an  accurate  description  of the
Membership  Interest so issued  transferred or assigned,  including whether such
new Member,  transferee  or assignee has been or will be admitted to the Company
as a Substitute  Member or  Additional  Member,  as the case may be, and provide
copies of the same to the Members.  Any amendment or revision to Schedule I made
in  accordance  with this  Agreement  shall not be deemed an  amendment  to this
Agreement. Any reference in this Agreement to Schedule I shall be deemed to be a
reference to Schedule I as amended and in effect from time to time.

Section  2.2  Name.  The name of the  limited  liability  company  formed by the
Original Agreement and by the filing of the Certificate of Formation is "Motient
Satellite  Ventures  LLC".  The  business of the Company may be  conducted  upon
compliance with all applicable laws under any other name  designated,  from time
to time, by the Board.

Section 2.3 Term. The term of the Company commenced on the date of the filing of
the  Certificate  of  Formation  in the office of the  Secretary of State of the
State of Delaware and shall  continue  until  dissolved in accordance  with this
Agreement, or if sooner, in accordance with the Delaware Act.

Section 2.4  Registered  Agent and Office.  The Company's  registered  agent and
office in Delaware  shall be  Corporation  Service  Company,  1013 Centre  Road,
Wilmington,  Delaware,  19805.  At any time,  the Board  may  designate  another
registered agent and/or registered  office,  provided such new designation shall
not adversely affect any Member.

Section 2.5 Principal Place of Business.  The principal place of business of the
Company shall be at 10802 Parkridge  Boulevard,  Reston,  Virginia 20191. At any
time,  the Board may change the  location of the  Company's  principal  place of
business.

Section  2.6  Qualification  in Other  Jurisdictions.  The Board shall cause the
Company to be qualified,  formed or registered  under assumed or fictitious name
statutes or similar  laws in any  jurisdiction  in which the  Company  transacts
business in which such  qualification,  formation or registration is required or
desirable.

Section 2.7 Agreement. This Agreement completely amends, restates and supersedes
the Original Agreement.

ARTICLE III

                        PURPOSE AND POWERS OF THE COMPANY

Section  3.1  Purpose.  The Company is formed for the object and purpose of, and
the nature of the  business  to be  conducted  and  promoted  by the Company is,
engaging in any lawful act or activity for which limited liability companies may
be  formed  under  the  Delaware  Act and  engaging  in any  and all  activities
necessary, convenient, desirable or incidental to the foregoing.

Section  3.2  Powers  of the  Company.  The  Company  shall  have the  power and
authority to take any and all actions necessary, appropriate, proper, advisable,
convenient or incidental to or for the  furtherance of the purposes set forth in
Section 3.1.

Section  3.3  Limitations  on  Company  Powers.  Notwithstanding  the  foregoing
provisions of Section 3.2, the Company shall not do business in any jurisdiction
that would jeopardize the limitation on liability  afforded to the Members under
the Delaware Act or this Agreement in such jurisdiction or elsewhere.

ARTICLE IV

                   CAPITAL CONTRIBUTIONS AND CAPITAL ACCOUNTS

Section 4.1       Capital Contributions.

(a) The Capital Contribution of each Member and Additional Member, if any, shall
be the  aggregate  amounts of money and the fair  market  value of any  property
(other than money) that such Member contributes to the capital of the Company in
exchange  for  Units  and a  Membership  Interest  pursuant  to  the  Investment
Agreement or a  subscription  agreement  entered into by a Member or  Additional
Member in accordance  with Section 9.1, as the case may be. The Initial  Capital
Contributions of the Members are set forth on Schedule I hereto. At the Investor
Option Closing,  the Investors shall make the Capital  Contributions and receive
the  number  of  Investor  Units  described  in  Section  2.1 of the  Investment
Agreement.  Capital  Contributions  shall be paid in the manner  provided in the
Investment Agreement or subscription  agreement,  as the case may be. Subject to
Section  9.1,  the  Company  may admit  Persons as Members  and issue  Units and
Membership  Interests to such Persons  without  obligating  such Persons to make
Capital Contributions.

(b) Following the Initial Capital  Contributions  described in clause (a) above,
no Member shall be required or permitted to contribute additional capital to the
Company except (i) as contemplated by the Investment  Agreement and (ii) subject
to Section 5.2 and the  pre-emptive  rights and other  applicable  provisions of
Article IX hereof, pursuant to a subscription agreement approved by the Board.

Section 4.2       Status of Capital Contributions.

(a) Except as otherwise  provided in this  Agreement,  no Member shall demand or
receive a return of its Capital Contribution and no return of a Member's Capital
Contribution  shall  be  made  hereunder  if  such  distribution  would  violate
applicable  state law.  Under  circumstances  requiring  a return of any Capital
Contribution, no Member shall have the right to demand or receive property other
than cash, except as may be specifically provided in this Agreement.

(b) No Member shall receive any interest,  salary or drawing with respect to its
Capital  Contribution or its Capital Account or for services  rendered on behalf
of the Company or  otherwise  in its  capacity as a Member,  except as otherwise
specifically  provided in this  Agreement.  Nothing  herein  shall  preclude any
Member from serving the Company in another  capacity,  including as an employee,
or otherwise  dealing with the Company in its individual  capacity and receiving
compensation or consideration therefor.

(c) Except as otherwise  provided herein or by applicable state law, the Members
shall be liable only to make Capital  Contributions  as provided in Section 4.1,
and no Member shall be required to lend any funds to the Company nor to make any
additional  Capital  Contributions.  No Member shall have any personal liability
for the repayment of any Capital Contribution of any other Member.

Section 4.3 Membership Interest. A Membership Interest shall for all purposes be
personal property. A Member has no interest in specific Company property.

Section 4.4 Capital Accounts.

(a)      An  individual  Capital Account shall be established and maintained for
         each Member.

(b)      The  Capital  Account of each Member shall be  maintained in accordance
         with the following provisions:

          (i) to such  Member's  Capital  Account  there shall be credited  such
          Member's Capital  Contribution,  such Member's  distributive  share of
          Profits  and  items of gross  income  and gain and the  amount  of any
          Company  liabilities  that  are  assumed  by such  Member  or that are
          secured by any Company assets distributed to such Member;

          (ii) to such  Member's  Capital  Account  there  shall be debited  the
          amount  of cash  and the  Gross  Asset  Value  of any  Company  assets
          distributed  to  such  Member   pursuant  to  any  provision  of  this
          Agreement,  such  Member's  distributive  share of Losses and items of
          gross  deduction  and loss and the amount of any  liabilities  of such
          Member  that are  assumed by the  Company  or that are  secured by any
          property contributed by such Member to the Company; and

          (iii) in determining  the amount of any liability for purposes of this
          Subsection 4.4(b), there shall be taken into account Section 752(c) of
          the  Code  and any  other  applicable  provisions  of the Code and the
          Treasury Regulations.

ARTICLE V

                                     MEMBERS

Section 5.1 Powers of Members.  Subject to Section 6.1,  the Members  shall have
the  power to  exercise  any and all  rights or powers  granted  to the  Members
pursuant to the express terms of the Delaware Act or this  Agreement.  Except as
otherwise  specifically  provided by this  Agreement or required by the Delaware
Act, no Person, including any Member, (a) shall have the power to be an agent of
the Company or (b) shall have any right,  power or authority (1) to transact any
business  in the name of the  Company,  (2) to act for,  or on  behalf  of,  the
Company or (3) to bind the Company.

Section 5.2  Consent of Members.  Notwithstanding  any  provision  hereof to the
contrary,  until the Restriction  Termination  Date, the Company,  and the Board
acting on behalf of the Company,  shall not conduct any business,  engage in any
activity  or take any  action,  other than  those  consistent  with,  reasonably
necessary for, or in  furtherance of the provisions  contained in the Investment
Agreement or the Ancillary Agreements and the transactions contemplated thereby,
without the prior written  consent of the Required  Investor  Majority.  Without
limiting the  generality of the  foregoing,  until the  Restriction  Termination
Date,  except as  specifically  permitted  by the  Investment  Agreement  or the
Ancillary  Agreements,  the Company will not take any of the  following  actions
without the prior written consent of the Required Investor Majority:

          (i) create any  committee  of the Board,  or change the size or agreed
          composition of the Board;

          (ii) declare or pay distributions to the Members;

          (iii) form any direct or indirect  subsidiaries  or a joint venture in
          which the Company or one of its subsidiaries is a party;

          (iv) (A) make any material change in the nature of the business of the
          Company as proposed to be developed hereunder and under the Investment
          Agreement  and the  Ancillary  Agreements  and  carried on at the date
          hereof  or  engage  in any new  line of  business,  or (B)  assign  or
          otherwise  transfer any of its rights or  obligations  under the Asset
          Sale Agreement,  the Research and  Development  Agreement or any other
          Ancillary Document;

          (v) adopt or approve its annual  operating  budget  including  capital
          expenditures  and  other  project   spending  or  materially   deviate
          therefrom;

          (vi) modify its  certificate  of  formation  or this  Agreement in any
          material respect;

          (vii)  enter  into,  or waive or  modify  (A) any  provision  of,  any
          registration  rights  agreement  or  management  agreement,   (B)  any
          executive employment  agreement,  or (c) any agreement with Motient or
          any of its  subsidiaries  or other  Affiliates,  in each case,  in any
          material respect;

          (viii)  elect or  terminate  any senior  management  of the Company or
          compensate such persons from funds of the Company;

          (ix) redeem or repurchase any Membership  Interests,  or repurchase or
          repay any indebtedness prior to its stated maturity;

          (x) except in the ordinary course of business, hypothecate,  mortgage,
          pledge,  charge or encumber any assets having a value in the aggregate
          in excess of $100,000;

          (xi) borrow or lend aggregate  amounts in excess of $100,000 or lesser
          amounts if outside the ordinary course of business;

          (xii)  declare   bankruptcy,   dissolve,   voluntarily   liquidate  or
          voluntarily wind-up;

          (xiii)  enter into any  contract or  agreement  outside  the  ordinary
          course of business which involves aggregate consideration in excess of
          $100,000 per annum;

          (xiv)  acquire or dispose  of any  assets in a single  transaction  or
          series of related  transactions for aggregate  consideration in excess
          of $100,000 per annum;

          (xv)  terminate  or  retain  accountants,   or  amend  or  modify  its
          accounting practices in any material respect,  except that the Company
          may (i) retain a "Big Five"  accounting  firm and (ii) amend or modify
          its   accounting   practices   to  the  extent  such   amendments   or
          modifications  are made by  Motient  with  respect  to its  accounting
          practices;

          (xvi) authorize,  create, allot, reserve or issue additional interests
          or Units of the Company;

          (xvii) register or offer securities for public sale;

          (xviii) effect any merger,  amalgamation,  reorganization  or business
          combination or sale or conveyance of the property of the Company as an
          entirety or substantially as an entirety;

          (xix) assume,  guaranty,  endorse or otherwise  become liable upon the
          obligation of any Member or any of their respective Affiliates;

          (xx)  purchase or acquire any  property  or assets or  obligations  or
          stock  of or  interest  in,  make  any  capital  contribution  to,  or
          otherwise  invest  directly or indirectly in or make loans or advances
          (except  for  expenses  of  directors  of  the  Company   incurred  in
          connection  with any  meeting  of the  Board) to, any Member or any of
          their respective Affiliates;

          (xxi) pay or incur any obligation for the payment of salaries, fees or
          other  remuneration,  or  change  the  rate of  compensation  or other
          remuneration,  or pay any  debts  claimed  to be  owing,  directly  or
          indirectly,  to any Member or  director  of the  Company or any of its
          subsidiaries  or to any  firm or  corporation  in which  they  have an
          interest  other  than (A) any  employment,  management  or  consulting
          arrangements  made with  management of the Company or directors of the
          Company;  and (B) customary  fees and expenses of the directors of the
          Company or any subsidiary  paid in connection  with any meeting of the
          Board of the Company or such subsidiary; and

          (xxii)  enter  into any  transaction  with any  Member or any of their
          respective  Affiliates  unless  such  transaction  is on terms no less
          favorable  to the Company  than can be obtained  from an  unaffiliated
          third party.

Following the Restriction Termination Date, the Company will not take any of the
actions set forth in clauses (xix) through  (xxii) of Section 5.2 hereof without
the prior written consent of the Required  Investor Majority and, for so long as
Motient  still  holds in excess  of 20% of the  Percentage  Interests,  Motient;
provided,  that if the Percentage  Interest held by Motient falls below 20% as a
result of the issuance of new interests by the Company,  Motient's consent shall
continue to be required until the earlier of (i) the date Motient ceases to hold
at least five percent (5%) of the Percentage Interests and (ii) the date Motient
transfers any of its Membership  Interest to a third party.  For the purposes of
applying  this  Section  5.2,  "Affiliates"  of a Person  shall also include any
entity in which a Member or Family  Member or a Person in control of a Member or
Family  Member  has a 10% or  greater  direct or  indirect  equity  interest  or
financial equivalent.

Section 5.3 Actions of the  Members.  Any action of the  Company  requiring  the
consent or approval of the Members,  or any class  thereof,  shall be taken by a
consent  in  writing  signed by  Members  holding  not less than the  Percentage
Interests necessary to take such action pursuant to this Agreement.

Section 5.4 Partition. Each Member waives any and all rights that it may have to
maintain an action for partition of the Company's property.

Section 5.5  Resignation.  A Member may not resign from the Company prior to the
dissolution  and winding up of the  Company.  A Member  attempting  to resign in
violation of this  Agreement  shall not be entitled to receive any  distribution
and shall not otherwise be entitled to receive the fair value of its  Membership
Interest except as otherwise expressly provided for in this Agreement.

ARTICLE VI

                                   MANAGEMENT

Section 6.1       The Board of Directors.

(a)      General.

          (i) The business and affairs of the Company shall be managed under the
          direction  of the Board of Directors  (the  "Board") and all powers of
          the  Company  which  are not by this  Agreement  or the  Delaware  Act
          required  to be  exercised  by the  Members  are hereby  vested in the
          Board.  The Board  shall have the power to delegate  authority  to the
          officers and such other employees,  agents and  representatives of the
          Company as it may from time to time deem appropriate and in accordance
          with this Agreement.  Any delegation of authority by the Board to take
          any action  must be  approved by the Board in the same manner as would
          be required for the Board to take such action  directly.  The Members,
          in their capacity as such, shall have no part in the management of the
          Company  and shall have no  authority  or right to act on behalf of or
          bind the Company in  connection  with any matter,  except as set forth
          herein and such  matters as deemed  necessary  or  appropriate  by the
          Board of Directors;  provided,  that nothing herein shall preclude any
          Member from serving the Company as a director, officer or agent of the
          Company  following such Member's election or appointment in accordance
          with the terms of this Agreement.

          (ii) All lawful determinations, decisions and actions made or taken by
          the Board shall be conclusive and absolutely binding upon the Company,
          the Members and their respective successors and assigns.

          (iii) The  directors  serving  on the  Board  shall be  "managers"  as
          defined in the Delaware Act;  provided,  that the directors shall only
          have the rights, powers and authority set forth in this Agreement and,
          unless expressly authorized by the Board, a director,  acting alone in
          such capacity, shall have no authority or right to act on behalf of or
          bind the Company in connection with any matter.

(b)  Qualifications  of  Directors.  No person  shall be elected or  appointed a
director if that person is less than 18 years of age, is of unsound mind and has
been found so by a court, is not an individual, or has the status of a bankrupt.
Directors may, but need not be, Members.

(c)      Number, Elections, Removal.

          (i) The Board shall consist of seven (7) directors.

          (ii) Until the Investor Option Closing, the directors shall be elected
          as follows:

               (1)  Investors  shall be entitled  to elect three (3)  directors,
               with each  Investor  Group (or  Investor or group of Investors to
               which members of such Investor Group transferred at least a three
               percent (3%) Percentage  Interest and expressly  transferred such
               Investor  Group's right to elect a Director  under this Agreement
               (an  "Investor  Group  Assignee")),  acting  through its Investor
               Group Designee,  electing one director and the Investors,  voting
               as a separate class,  electing the remaining Investor  Directors,
               if any, by the affirmative  vote of Investors  holding a majority
               of the Percentage Interests held by all Investors.

               (2) Motient shall be entitled to elect four (4) directors.

          (iii) Following the Investor  Option  Closing,  the directors shall be
          elected as follows:

               (1) For so long as the  Investors  continue  to hold in excess of
               40% of the Percentage  Interests,  Investors shall be entitled to
               elect four (4)  directors,  with each Investor Group (or Investor
               Group  Assignee  thereof),  acting  through  its  Investor  Group
               Designee,  electing one director and the  Investors,  voting as a
               separate class,  electing the remaining Investor Directors by the
               affirmative   vote  of  Investors   holding  a  majority  of  the
               Percentage Interests held by all Investors;  provided, that if at
               any time the  Investors  holds  less  than 40% of the  Percentage
               Interests,   the  Investors  shall   thereafter  be  entitled  to
               designate two (2) directors (by the affirmative vote of Investors
               holding  a  majority  of the  Percentage  Interests  held  by all
               Investors) and the two Board seats  previously  designated by the
               Investors  shall be elected by the Members  holding a majority of
               the Percentage  Interests;  provided further, that if at any time
               the Investors  holds less than 20% of the  Percentage  Interests,
               the Investors  shall  thereafter be entitled to designate one (1)
               director (by the affirmative vote of Investors holding a majority
               of the Percentage  Interests held by all Investors) and the Board
               seat  previously  designated by the Investors shall be elected by
               the Members holding a majority of the Percentage Interests.

               (2) For so long as Motient  continues to hold in excess of 20% of
               the  Percentage  Interests,  Motient  shall be  entitled to elect
               three (3) directors;  provided, that if at any time Motient holds
               less  than  20% of the  Percentage  Interests,  Motient  shall be
               entitled to  designate  one (1)  director and the two Board seats
               previously  designated by Motient shall be elected by the Members
               holding a majority of the Percentage Interests.

          (iv)  For so long  as the  Spectrum  Investor  Group  continues  to be
          entitled  to elect a director  under  Sections  6.1(c)(ii)  and (iii),
          Spectrum Space Equity Investors IV, Inc., the wholly-owned  subsidiary
          of Spectrum Equity  Investors IV, L.P. shall be entitled to elect such
          director,  and such  director  shall be a  representative  of Spectrum
          Equity Investors IV, L.P.. Spectrum Equity Investors IV, L.P. shall be
          a third-party beneficiary of this Agreement to the extent necessary in
          order to enforce its rights under this 6.1(c)(iv).

          (v)  For so  long  as the  Columbia  Investor  Group  continues  to be
          entitled  to elect a director  under  Sections  6.1(c)(ii)  and (iii),
          Columbia  Space (QP),  Inc., the  wholly-owned  subsidiary of Columbia
          Capital  Equity  Partners  (QP),  L.P. shall be entitled to elect such
          director,  and such  director  shall be a  representative  of Columbia
          Capital Equity Partners (QP),  L.P..  Columbia Capital Equity Partners
          (QP), L.P. shall be a third-party beneficiary of this Agreement to the
          extent necessary in order to enforce its rights under this 6.1(c)(v).

          (vi) The right of each Investor  Group or Investor  Group  Assignee to
          elect an Investor Director  pursuant to Sections  6.1(c)(ii) and (iii)
          shall continue until the date on which such Investor Group or assignee
          no  longer  holds  at  least  three  percent  (3%)  of the  Percentage
          Interests.

          (vii) Directors shall be elected annually in the manner provided above
          on or prior to July 1 of each year and each director shall hold office
          until a successor is elected and qualified,  or until such  director's
          earlier death or resignation or removal in the manner provided in this
          Agreement. Voting for directors shall not be cumulative.

          (viii)  In the  case  of any  vacancy  in the  office  of an  Investor
          Director,  a  successor  shall  be  elected  to  hold  office  for the
          unexpired  term of such director by the Investor or group of Investors
          that was entitled to elect such Investor Director.  In the case of any
          vacancy  in the office of a Motient  Director,  a  successor  shall be
          elected to hold  office for the  unexpired  term of such  director  by
          Motient. Any director who shall have been elected by a specified class
          or Member may be removed during such director's term of office, either
          for cause or without cause by, and only by, the affirmative  vote of a
          majority of such  specified  class or Member,  as the case may be, and
          any such vacancy thereby created may be filled by such specified class
          or classes.

          (ix) Any person  elected as a director  shall be deemed to have agreed
          to accept such director's  rights,  authority,  duties and obligations
          hereunder.  In the  performance  and  discharge  of  such  duties  and
          obligations  the director  shall act honestly and in good faith with a
          view to the best interests of the Company and shall exercise the care,
          diligence and skill that a reasonably prudent person would exercise in
          comparable circumstances.

(d) Resignation. Any director may resign at any time by giving written notice to
the Board.  Such  resignation  shall take effect at the time  specified  in such
notice  or, if the time be not  specified,  upon  receipt  thereof by the Board.
Unless otherwise specified therein,  acceptance of such resignation shall not be
necessary to make it effective.

(e)      Meetings.

          (i)  Regular  Meetings.  The  Board  shall  meet  no less  often  than
          quarterly,  unless otherwise agreed by at least 2/3 of the Board. Such
          meetings  shall be held on such  date as shall  be  determined  by the
          President or a majority of the Board.

          (ii) Other Meetings. Other meetings of the Board shall be held at such
          times as the Chairman,  the President or a majority of the Board shall
          from time to time determine.

          (iii) Notice of Meetings.  The Secretary  shall give written notice to
          each  director of each meeting of the Board,  which notice shall state
          the place, date, time and purpose of such meeting. Notice of each such
          meeting shall be given to each director,  if by mail, addressed to him
          at his  residence or usual place of business,  at least five  Business
          Days before the day on which such  meeting is to be held,  or shall be
          sent to him at such place by telecopy, telegraph, cable, or other form
          of recorded communication,  or be delivered personally or by telephone
          not later than two (2) days before the day on which such meeting is to
          be held. A written waiver of notice,  signed by the director  entitled
          to notice, whether before or after the time of the meeting referred to
          in such  waiver,  shall be deemed  equivalent  to notice.  Neither the
          business  to be  transacted  at, nor the purpose of any meeting of the
          Board  need be  specified  in any  written  waiver of notice  thereof.
          Attendance of a director at a meeting of the Board shall  constitute a
          waiver of notice of such meeting.

          (iv) Place of Meetings.  The Board may hold its meetings at such place
          or places  within or without  the State of  Delaware  as the Board may
          from  time  to  time  determine,  or as  shall  be  designated  in the
          respective notices or waivers of notice of such meetings.

          (v) Quorum and Manner of Acting.

               (1) A  majority  of the  directors  then  in  office  (or who are
               members of any committee of the Board) shall be present in person
               at any meeting of the Board (or a committee thereof,  as the case
               may be) in order to  constitute a quorum for the  transaction  of
               business  at such  meeting,  and the vote of a majority  of those
               directors,  or  members  of such  committee,  present at any such
               meeting at which a quorum is present  shall be necessary  for the
               passage of any resolution or act of the Board or such  committee,
               except as otherwise expressly required by this Agreement.  In the
               absence  of a quorum  for any such  meeting,  a  majority  of the
               directors  present  thereat may adjourn such meeting from time to
               time until a quorum shall be present.

               (2) Prior to the Investor Option Closing,  any decision on behalf
               of the Company as to any matter that concerns the Company, on the
               one hand,  and  Services,  on the  other  hand,  arising  out of,
               relating  to,  or  in  connection   with,   the   interpretation,
               performance,  nonperformance,  validity, breach or termination of
               the Asset Sale Agreement,  the Research and Development Agreement
               or  any  of  the  Ancillary   Agreements   or  the   transactions
               contemplated  thereby (including waivers,  consents,  amendments,
               etc.),  shall  be made by a  special  committee  of the  board of
               directors of the Company,  consisting of five (5) members,  three
               (3) of whom shall be Investor Directors and two (2) of whom shall
               be  Motient  Directors;  provided,  that,  as long as  Motient or
               Services is not in Bankruptcy,  the foregoing provision shall not
               apply to decisions regarding assignments by the Company of rights
               or  obligations  under  such  agreements.  Without  limiting  the
               foregoing,  the  determination  as to  whether,  when and how the
               Company  exercises  its rights with respect to the closing of the
               transactions  contemplated  by the Asset Sale Agreement  shall be
               made, in its sole discretion,  by the Required Investor Majority,
               and   Motient   agrees  to  cause  the   Company  to  follow  the
               instructions of the Required Investor Majority with regard to the
               steps to be taken in connection therewith.

          (vi) Organization.  At each meeting of the Board, one of the following
          shall act as chairman of the meeting  and  preside,  in the  following
          order of precedence:

               (1) the Chairman;

               (2) the President;

               (3) any director chosen by a majority of the directors present.

          The  Secretary  or, in the case of his  absence,  any person  whom the
          chairman of the meeting  shall  appoint shall act as secretary of such
          meeting and keep the minutes thereof.

(f) Committees of the Board.  The Board may, by resolution  passed by a majority
of the whole Board,  designate one or more committees  consisting of two or more
directors;  provided,  that each  committee  consist  of at least  one  Investor
Director and one Motient  Director.  Except as otherwise  expressly  required by
this  Agreement,  any  committee  of the Board,  to the extent  provided  in the
resolution of the Board designating such committee,  shall have and may exercise
all the powers and authority of the Board in the  management of the business and
affairs of the Company,  and may authorize the seal of the Company to be affixed
to all papers  which may  require  it.  Each  committee  of the Board shall keep
regular  minutes  of its  proceedings  and  report the same to the Board when so
requested by the Board.

(g) Directors'  Consent in Lieu of Meeting.  Any action required or permitted to
be taken at any  meeting of the Board or of any  committee  thereof may be taken
without a meeting,  without  prior  notice and  without a vote,  if a consent in
writing,  setting forth the action so taken,  shall be signed by all the members
of the Board or such committee and such consent is filed with the minutes of the
proceedings of the Board or such committee.

(h) Action by Means of Telephone or Similar Communications Equipment. Any one or
more members of the Board,  or of any committee  thereof,  may  participate in a
meeting  of the Board or such  committee  by means of  conference  telephone  or
similar communications  equipment by means of which all persons participating in
the meeting can hear each other,  and  participation  in a meeting by such means
shall constitute presence in person at such meeting.

(i)  Compensation.  Directors shall not receive any salary or  compensation  for
their services as directors or as members of committees, except as authorized by
Members holding a majority of the Percentage Interests in the manner provided in
Section 5.3. The  directors  shall be entitled to be reimbursed  for  travelling
expenses  properly  incurred by them in  attending  meetings of the Board or any
committee  thereof.  Nothing herein shall preclude any director from serving the
Company in any other capacity and receiving compensation therefor.

Section 6.2       Officers.

(a) Officers.  The officers of the Company shall be the Chairman, the President,
the  Secretary  and a  Treasurer  and may  include  one or more Vice  Presidents
(including,  one or more Senior Vice  Presidents),  and such other officers with
such titles as the Board may  determine.  Any two or more offices may be held by
the same person.

(b) Authority  and Duties.  All officers  shall have such  authority and perform
such  duties  in the  management  of the  Company  as may be  provided  in  this
Agreement or, to the extent not so provided, by resolution of the Board.

(c)      Term of Office, Resignation and Removal.

          (i) Subject to Section  5.2,  each  officer  shall be appointed by the
          Board and shall hold office for such term as may be  determined by the
          Board.  Each officer  shall hold office until his  successor  has been
          appointed and qualified or his earlier death or resignation or removal
          in the manner hereinafter provided.

          (ii) Any  officer may resign at any time by giving  written  notice to
          the Board or the President.  Such resignation shall take effect at the
          time specified in such notice or, if the time be not  specified,  upon
          receipt  thereof  by the Board or the  President,  as the case may be.
          Unless  otherwise  specified  therein,  acceptance of such resignation
          shall not be necessary to make it effective.

          (iii) All officers and agents  appointed by the Board shall be subject
          to removal, with or without cause, at any time by the Board.

(d)  Vacancies.  Any vacancy  occurring  in any office of the  Company,  for any
reason, shall be filled by action of the Board.

(e) The  Chairman.  The  Chairman of the Board (the  "Chairman")  shall have the
power to call special  meetings of the Board and, if present,  to preside at all
meetings of the  Members  and all  meetings  of the Board.  The  Chairman  shall
perform all duties  incident to the office of Chairman of the Board and all such
other  duties as may from time to time be  assigned  to him by the Board or this
Agreement.

(f) The President.  The President  shall have general and active  management and
control of the business  and affairs of the  Company,  subject to the control of
the  Board,  and  shall see that all  orders  and  resolutions  of the Board are
carried into effect.  The  President  shall  perform all duties  incident to the
office  of  President  and all such  other  duties  as may from  time to time be
assigned by the Board or this Agreement.

(g) Vice Presidents.  Vice Presidents, if any, in order of their seniority or in
any other order  determined by the Board,  shall generally  assist the President
and perform such other duties as the Board or the President shall prescribe, and
in the absence or  disability  of the  President,  shall  perform the duties and
exercise the powers of the President.

(h) The Secretary.  The Secretary shall, to the extent  practicable,  attend all
meetings of the Board and all meetings of the Members and shall record all votes
and the minutes of all  proceedings  in a book to be kept for that purpose,  and
shall  perform the same duties for any  committee of the Board when so requested
by such  committee.  The Secretary shall give or cause to be given notice of all
meetings of the Members and of the Board, shall perform such other duties as may
be prescribed by the Board or the President and shall act under the  supervision
of the  President.  The  Secretary  shall keep in safe  custody  the seal of the
Company  and affix the same to any  instrument  that  requires  that the seal be
affixed to it and which shall have been duly  authorized  for  signature  in the
name of the  Company  and,  when so  affixed,  the seal shall be attested by his
signature or by the signature of the Treasurer. The Secretary shall keep in safe
custody  the  certificate  books and Member  records  and such  other  books and
records  of the  Company  as the Board or the  President  may  direct  and shall
perform  all other  duties  incident to the office of  Secretary  and such other
duties as from time to time may be assigned by the Board or the President.

(i) The  Treasurer.  The  Treasurer  shall have the care and  custody of all the
funds of the  Company  and  shall  deposit  such  funds  in such  banks or other
depositories as the Board, or any officer or officers,  or any officer and agent
jointly,  duly  authorized  by the Board,  shall,  from time to time,  direct or
approve.  The  Treasurer  shall  disburse  the  funds of the  Company  under the
direction of the Board and the  President.  The Treasurer  shall keep a full and
accurate  account of all moneys  received and paid on account of the Company and
shall render a statement of accounts  whenever the Board or the President  shall
so request.

(j) Compensation. Subject to Section 5.2(viii), the compensation of the officers
of the Company shall be fixed by the Board, subject to any employment agreements
between the Company and any such officers.

ARTICLE VII

                                   ALLOCATIONS

Section 7.1       Profits and Losses.

(a) Profits for any Fiscal Year shall be  allocated,  after giving effect to the
special allocations set forth in Sections 7.1(c) and 7.2 below, in the following
order of priority:

     (i) First,  among the Investors in proportion to, and to the extent of, any
     prior allocations to the Investors of Losses pursuant to Section 7.1(b)(iv)
     hereof for all prior Fiscal Years;

     (ii) Second,  100% to Motient  until the  cumulative  Profits  allocated to
     Motient for all Fiscal Years pursuant to this Section  7.1(a)(ii) are equal
     to the  cumulative  Losses  previously  allocated to Motient for all Fiscal
     Years pursuant to Section 7.1(b)(iii) hereof;

     (iii)  Third,  to each  Member  in the  proportion  required  such that the
     cumulative  Profits  allocated to each Member for all Fiscal Years pursuant
     to  this  Section  7.1(a)(iii)  equals  the  cumulative  Losses  previously
     allocated  to each such  Member  for all prior  Fiscal  Years  pursuant  to
     Section 7.2(b)(ii); and

     (iv) Thereafter,  the balance, if any, among the Members in accordance with
     their Percentage Interests.

(b) Losses for any Fiscal Year shall be  allocated,  after giving  effect to the
special  allocations  set forth in Section 7.2 below and  Subsection (c) of this
Section 7.1, in the following order of priority:

     (i) First,  among the Members in  proportion  to, and to the extent of, any
     prior allocations to the Members of Profits pursuant to Section  7.1(a)(iv)
     above for all prior Fiscal Years;

     (ii) Second, among the Members in proportion to their respective Unreturned
     Subsequent Capital  Contributions  until the sum of the Investors' Adjusted
     Capital  Account  balances are equal to their  Unreturned  Initial  Capital
     Contributions;

     (iii) Third, 100% to Motient until its Adjusted Capital Account balance has
     been reduced to zero; and

     (iv)  Thereafter,  among the Investors in  proportion  to their  respective
     Adjusted Capital Account balances.

(c)  Notwithstanding  Sections  7.1(b)(i)  and  (ii)  hereof,  Losses  allocated
pursuant  to Section  7.1(b) to any Member for any Fiscal  Year shall not exceed
the  maximum  amount of Losses  that may be  allocated  to such  Member  without
causing such Member to have an Adjusted  Capital  Account  Deficit at the end of
such Fiscal Year.  Any Losses in excess of the limitation in this Section 7.1(c)
shall be specially  allocated  solely to the other Members to the maximum extent
permitted by this Section 7.1(c).  Thereafter,  notwithstanding  Section 7.1(a),
subsequent Profits shall be allocated to reverse any Losses specially  allocated
pursuant to the preceding sentence.

(d) An  allocation  of  Profits  or Losses to a Member  shall be  treated  as an
allocation to such Member of the same share of each item of income,  gain,  loss
and deduction that is taken into account in computing such Profits or Losses, as
the case may be.

Section 7.2 Special Allocations. The following special allocations shall be made
in the following order:

(a)  Minimum  Gain  Chargeback.  If  there is a net  decrease  in  Minimum  Gain
(determined  as  provided  in  Treasury   Regulations  Sections  1.704-2(d)  and
1.704-2(g)) during any Fiscal Year, certain items of income and gain,  including
gross  income or gain,  shall be  allocated  to the  Members in the  amounts and
manner described in Treasury Regulations Section 1.704-2(f). This Section 7.2(a)
is intended to comply with the minimum gain chargeback  requirement  relating to
partnership non-recourse liabilities (as defined in Treasury Regulations Section
1.704-2(f)) and shall be so interpreted.

(b)  Partner  Non-recourse  Debt  Minimum  Gain  Chargeback.  If  there is a net
decrease in Minimum Gain  attributable to partner  non-recourse debt (determined
pursuant to Treasury  Regulations  Section  1.704-2(i))  during any Fiscal Year,
certain  items of income  and gain,  including  gross  income or gain,  shall be
allocated  as  quickly as  possible  to those  Members  which had a share of the
Minimum  Gain  attributable  to  the  partner   non-recourse  debt  (such  share
determined  pursuant  to  Treasury  Regulations  Section  1.704-1(i)(5))  in the
amounts and manner described in Treasury Regulations Section 1.704-2(i) and (j).
This  Section  7.2(b) is intended to comply  with the  minimum  gain  chargeback
requirement  relating  to  partner  non-recourse  debt  set  forth  in  Treasury
Regulations Section 1.704-2(i)(4)) and shall be so interpreted.

(c)  Allocation  of   Non-recourse   Deductions.   Deductions   attributable  to
obligations  with  respect  to which a Member  bears the  economic  risk of loss
within  the  meaning  of  Treasury  Regulation  Section  1.704-2(b)(4)  shall be
allocated to the Member or Members that bear the economic  risk of loss for such
debt  in  accordance  with  the  requirements  of  Treasury  Regulation  Section
1.704-2(i)(1).  "Nonrecourse  Deductions"  (as such term is defined in  Treasury
Regulations  Sections  1.704-2(b)(1)  and  1.704-2(c))  of the Company  shall be
allocated to the Members in proportion to their Percentage Interests.

(d) Qualified Income Offset. In the event any Member  unexpectedly  receives any
adjustments,  allocations  or  distributions  described in Treasury  Regulations
Section  1.704-1(b)(2)(ii)(d)(4),  (5) or (6),  items of Company income and gain
(consisting  of a pro rata  portion  of each item of Company  income,  including
gross  income,  and gain for such year)  shall be  specially  allocated  to such
Member in an amount and manner  sufficient to eliminate,  to the extent required
by the Treasury Regulations, the Adjusted Capital Account Deficit of such Member
as quickly as possible,  provided  that an  allocation  pursuant to this Section
7.2(d)  shall be made if and only to the extent that such  Member  would have an
Adjusted  Capital  Account Deficit after all other  allocations  provided for in
this Article VII have been  tentatively  made as if this Section 7.2(d) were not
in the Agreement.

(e) Gross  Income  Allocation.  In the event any  Member  has a deficit  Capital
Account  at the end of any  Fiscal  Year that is in excess of the sum of (i) the
amount  such Member is  obligated  to restore and (ii) the amount such Member is
deemed to be  obligated  to restore  pursuant to the  penultimate  sentences  of
Treasury Regulations Sections 1.704-2(g)(1) and 1.704-2(i)(5), such Member shall
be specially  allocated  items of Company  income and gain  (consisting of a pro
rata portion of each item of Company income,  including  gross income,  and gain
for such year) in the amount of such  excess as  quickly as  possible,  provided
that an allocation  pursuant to this Section 7.2(e) shall be made if and only to
the extent that such Member  would have a deficit  Capital  Account in excess of
such sum after all other allocations  provided for in this Article VII have been
tentatively  made as if Section 7.2(d) above and this Section 7.2(e) were not in
the Agreement.

(f) Regulatory  Allocations.  The  allocations  set forth in Section  7.2(a)-(e)
hereof (the  "Regulatory  Allocations")  are  intended  to comply  with  certain
requirements of the Treasury Regulations.  It is the intent of the Members that,
to the extent possible,  all Regulatory  Allocations shall be offset either with
other  Regulatory  Allocations  or with  special  allocations  of other items of
Company  income,  gain,  loss or  deduction  pursuant  to this  Section  7.2(f).
Therefore,  the Board shall make such offsetting special  allocations of Company
income,  gain, loss and deduction in whatever manner it determines  appropriate,
so that,  after such  offsetting  allocations  are made,  each Member's  Capital
Account balance is, to the extent possible, equal to the Capital Account balance
such  Member  would  have if the  Regulatory  Allocations  were  not part of the
Agreement  and all Company  items were  allocated  pursuant  to Section  7.1. In
exercising  its  discretion,  the Board  shall  take  into  account  how  future
Regulatory Allocations pursuant to Sections 7.2(a) and (b) hereof that, although
not yet made, are likely to offset other Regulatory  Allocations previously made
under Section 7.2(c) hereof.

(g) Section 754  Adjustment.  To the extent an  adjustment  to the  adjusted tax
basis of any Company asset  pursuant to Section  734(b) or 743(b) of the Code is
required, pursuant to Treasury Regulations Section  1.704-1(b)(2)(iv)(m),  to be
taken  into  account  in  determining  Capital  Accounts,  the  amount  of  such
adjustment to the Capital  Accounts  shall be treated as an item of gain (if the
adjustment  increases  the  basis  of the  asset)  or loss  (if  the  adjustment
decreases such basis), and such gain or loss shall be specially allocated to the
Members in a manner  consistent with the manner in which their Capital  Accounts
are required to be adjusted pursuant to such regulation.

(h) Special  Allocations  Upon  Exercise of the Investor  Option.  Following the
Investor Option  Closing,  items of Company  income,  gain,  deduction and loss,
other than gain and loss from a Capital Event, shall be specially allocated in a
manner to cause the Members' Capital Accounts to be in the proportions that they
would have been in had the  Percentage  Interests of the Members in effect after
the Investor Option Closing been in effect as of the date hereof.

(i)  Special  Allocations  Upon the  Occurrence  of a  Capital  Event.  Upon the
occurrence of a Capital Event, items of Company income, gain, deduction and loss
attributable  to such Capital Event shall be specially  allocated in a manner to
cause each Member's  Adjusted  Capital  Account  balance to equal the sum of the
amounts of cash or the Gross Asset Value of other property distributable to such
Member pursuant to Article 8 hereof at such time assuming that all the remaining
assets of the Company  were sold for their  Gross  Asset  Values and the cash or
other property  received  therefrom was distributed to the Members in accordance
with the priorities set forth in Article 8 hereof.

Section 7.3       Allocation Rules.

(a) For purposes of determining the Profits, Losses or any other items allocable
to any period, Profits, Losses and any such other items shall be determined on a
daily,  monthly or other basis, as determined by the Board using any method that
is  permissible  under  Section  706 of the  Code and the  Treasury  Regulations
thereunder.

(b) Except as otherwise provided in this Agreement, all items of Company income,
gain, loss, deduction and any other allocations not otherwise provided for shall
be divided among the Members in the same  proportions  as they share Profits and
Losses for the Fiscal Year in question.

(c) The Members are aware of the income tax consequences of the allocations made
by this  Article  VII and  hereby  agree to be bound by the  provisions  of this
Article VII in reporting  their shares of Company income and loss for income tax
purposes.

Section 7.4       Section 704(c) of the Code.

(a) In accordance  with Section 704(c) of the Code and the Treasury  Regulations
thereunder,  income,  gain,  loss and  deduction  with  respect to any  property
contributed to the capital of the Company shall, solely for income tax purposes,
be allocated  among the Members so as to take account of any  variation  between
the  adjusted  basis of such  property to the  Company  for  federal  income tax
purposes and its initial Gross Asset Value.

(b) In the event the Gross Asset Value of any Company asset is adjusted pursuant
to the  definition  of "Gross  Asset  Value"  contained  in Section  1.1 hereof,
subsequent  allocations of income, gain, loss and deduction with respect to such
asset shall take account of any  variation  between the  adjusted  basis of such
asset for  federal  income tax  purposes  and its Gross  Asset Value in the same
manner  as  under  Section  704(c)  of the  Code  and the  Treasury  Regulations
thereunder.

(c)  Allocations  pursuant to this Section 7.4 shall be  calculated by the Board
using  any  permissible  method  under  Code  Section  704(c)  and the  Treasury
Regulations  promulgated  thereunder  and are solely for  purposes  of  federal,
state, and local taxes and shall not affect, or in any way be taken into account
in computing,  any Member's Capital Account or share of Profits,  Losses,  other
items, or distributions pursuant to any other provision of this Agreement.

Section 7.5 Uncertainties in Allocations and  Distributions.  In the event there
is an ambiguity  regarding the  application  of this Section 7 or Section 8 to a
particular  transaction,  the income and expense from such transaction  shall be
allocated  among the  Members,  and  distributions  of cash in  respect  of such
transaction shall be made, in such proportions that the Board, in its reasonable
discretion, deems equitable, practicable and consistent with this Agreement, the
regulations under the Code and other applicable law; provided,  however, that no
such  allocation or  distribution  by the Board shall  discriminate  against any
Member.

ARTICLE VIII

                                  DISTRIBUTIONS

Section 8.1  Distributions(a)  . Except as otherwise provided in Section 8.6 and
Section 13.3 below, the Company shall make  distributions of cash to the Members
in proportion to their respective Percentage Interests at such time or times and
in such amounts as the Board may determine in its sole discretion

Section 8.2  Distributions  to Pay Taxes. The Board shall endeavor to distribute
to the Members an amount sufficient for the Members to pay their tax liabilities
which arise in respect of their shares of cumulative net taxable income and gain
of the Company,  determined as set forth below by the Board, prior to the making
of any  distributions  pursuant  to  Sections  8.1 and  8.6  hereof.  Any  funds
distributed  pursuant to this  Section 8.2 shall reduce the amount that a Member
would otherwise  receive  pursuant to Sections 8.1 and 8.6. For purposes of this
Section  8.2, the amount of tax  distributions  made to a Member for any taxable
year shall be equal to the excess, if any, of (i) the product of (A) the excess,
if any,  of (I) its  cumulative  share  of net  taxable  income  or gain for the
current Fiscal Year and all prior Fiscal Years over (II) its cumulative share of
net taxable loss and deduction for all prior Fiscal Years and (B) the sum of the
highest  rate of  Federal,  state and local tax  imposed on the type of taxpayer
applicable  to such  Member  or in the case of a Member  that is a  pass-through
entity, the type of taxpayer applicable to the beneficial owners of interests in
such  pass-through  entity  for  such  year  with  respect  to items of the same
character as such net income and gain,  taking into account the deductibility of
state  and  local  taxes  for  Federal  income  tax  purposes  and based on such
reasonable  assumptions as the Board determines in good faith to be appropriate,
over (ii) the amount of any  distributions  made to such Member pursuant to this
Section 8.2 in a prior Fiscal Year.

Section 8.3 Dissolution. Upon the dissolution and winding up of the Company, the
assets of the Company shall be distributed to the Members as provided in Section
13.3 below.

Section 8.4 Withholding  Taxes. All amounts withheld pursuant to the Code or any
provision  of any state,  local or foreign tax law with  respect to any payment,
distribution  or  allocation  to the Company or the Members  shall be treated as
amounts  distributed  to the  Members  pursuant  to this  Article  VIII  for all
purposes  of  this  Agreement.  The  Company  is  authorized  to  withhold  from
distributions and to pay over to any federal, state, local or foreign government
any amounts required to be so withheld  pursuant to the Code or any provision of
any other federal,  state,  local or foreign law and shall allocate such amounts
to those Members with respect to which such amounts were withheld.

Section 8.5 Limitations on  Distribution.  Notwithstanding  any provision to the
contrary contained in this Agreement,  the Company shall not make a distribution
to the Members if such  distribution  in the  aggregate  would  violate  Section
18-607 of the Delaware Act or other applicable law.

Section 8.6 Capital  Proceeds.  Following  the receipt by the Company of Capital
Proceeds,  a portion of such Capital Proceeds  sufficient for each Member to pay
its tax  liabilities  which arise in respect of the Capital Event giving rise to
such Capital  Proceeds,  determined as set forth in Section 8.2 above,  shall be
distributed to the Members  pursuant to Section 8.2 above.  If the Board, in its
sole  discretion,  determines  that the Company shall  distribute  any remaining
Capital  Proceeds,  such Capital Proceeds shall be distributed among the Members
as follows:

(a) To the Members in a manner to cause the cumulative prior and current Capital
Proceeds  distributed  to  each  of  the  Members  to be in  the  same  relative
proportions as the Members' respective Percentage Interests;  provided, however,
that Capital  Proceeds  shall be  distributed  in  accordance  with this Section
8.6(a)  only  if it  results  in the  receipt  by the  Investors  of  cumulative
distributions  of Capital  Proceeds in an amount at least equal to twice the sum
of the Investors' aggregate Capital Contributions;

(b) Otherwise,  such Capital Proceeds shall be distributed  among the Members in
the following order of priority:

     (i) First, to the Investors in proportion to and to the extent of each such
     Investor's Unreturned Initial Capital Contributions;

     (ii)  Second,  to the Members in  proportion  to and to the extent of their
     Unreturned Subsequent Capital Contributions; and

     (iii)  Thereafter,  to the Members in accordance with the positive balances
     in their Capital  Accounts until all such positive  balances are reduced to
     zero.

ARTICLE IX

                              ADDITIONAL ISSUANCES,

                         TRANSFERS, ADMISSION OF MEMBERS

                                 AND CONVERSION

Section 9.1       Additional Issuances of Interests.

(a) In order to raise capital for Company  operations or to acquire  assets,  to
redeem or retire  Company  debt, or for any other valid  Company  purposes,  the
Board may, subject to the consent of the Members provided in Section 5.2 and the
provisions  of this Section 9.1, from time to time  determine  that it is in the
best interests of the Company to cause the Company to issue additional interests
in the Company to the Members or other  Persons and to admit such other  Persons
to the Company as Additional  Members  pursuant to Section 9.5. The Board shall,
subject to the consent of the Members  provided in Section  5.2,  determine  the
consideration  for and the terms  and  conditions  with  respect  to any  future
issuance of interests in the Company.

(b) The Company  shall not issue any  interests  in the Company  unless it first
delivers to each Member (each such Person being  referred to in this Section 9.1
as a "Buyer") a written  notice (the "Notice of Proposed  Issuance")  specifying
the type and amount of such  interests  that the Company  then  intends to issue
(the "Offered Interests"), all of the material terms, including the price (which
shall be a cash  price)  upon which the  Company  proposes  to issue the Offered
Interests  and  stating  that the Buyers  shall have the right to  purchase  the
Offered Interests in the manner specified in this Section 9.1 for the same price
per share and in accordance with the same terms and conditions specified in such
Notice of Proposed Issuance.

(c)  During  the ten (10)  consecutive  day  period  commencing  on the date the
Company delivers to all of the Buyers the Notice of Proposed  Issuance (the "Ten
Day  Period"),  the Buyers  shall have the option to  purchase  up to all of the
Offered  Interests  at the same  price and upon the same  terms  and  conditions
specified in the Notice of Proposed  Issuance.  Each Buyer  electing to purchase
Offered  Interests must give written notice of its election to the Company prior
to the expiration of the Ten Day Period.

(d) Each Buyer  shall have the right to purchase  up to that  percentage  of the
Offered Interests equal to the Percentage  Interest then held by such Buyer. The
amount of such Offered  Interests  that each Buyer is entitled to purchase under
this Section 9.1 shall be referred to as its "Proportionate Share."

(e) Each  Buyer  shall have a right of  oversubscription  such that if any other
Buyer  fails to elect to  purchase  his or its full  Proportionate  Share of the
Offered  Interests,  the other  Buyer(s)  shall,  among them,  have the right to
purchase up to the  balance of such  Offered  Interests  not so  purchased.  The
Buyers may exercise such right of  oversubscription by electing to purchase more
than their  Proportionate  Share of the Offered  Interests by so  indicating  in
their written notice given during the Ten Day Period.  If, as a result  thereof,
such oversubscription elections exceed the total number of the Offered Interests
available in respect to such  oversubscription  privilege,  the  oversubscribing
Buyers shall be cut back with respect to  oversubscriptions  on a pro rata basis
in accordance with their respective Proportionate Share or as they may otherwise
agree among themselves.

(f) If all of the  Offered  Interests  have not  been  purchased  by the  Buyers
pursuant to the  foregoing  provisions,  then the Company  shall have the right,
until the expiration of one hundred eighty (180)  consecutive days commencing on
the first day  immediately  following the  expiration of the Ten Day Period,  to
issue the Offered Interests not purchased by the Buyers at not less than, and on
terms no more  favorable in any  material  respect to the  purchaser(s)  thereof
than, the price and terms specified in the Notice of Proposed Issuance.  If such
remaining  Offered Interests are not issued within such period and at such price
and on such terms,  the right to issue in accordance with the Notice of Proposed
Issuance shall expire and the provisions of this Agreement  shall continue to be
applicable to the Offered Interests.

(g)  Notwithstanding  the  foregoing,  the rights  described in this Section 9.1
shall not apply with respect to the issuance of Excluded Securities.

Section 9.2 Transfers.  Except as set forth in Sections 9.2(c) and (d) or in the
Investment  Agreement,  no Member  shall be  permitted  to  transfer  any of its
Membership  Interests  to any Person  without the  consent of the other  Members
until either the  Investor  Option  Closing has occurred or the Investor  Option
lapses  in  accordance  with its  terms or is  irrevocably  waived by all of the
Investors("Restriction Termination Date"). Following the Restriction Termination
Date,  a Member may not  assign or  transfer  all or any part of its  Membership
Interest to any Person, except in compliance with the following:

(a) Right of First Refusal. In the event that after the Restriction  Termination
Date,  a Member  proposes  to transfer  all or a portion of its  interest in the
Company to any third party, other than in accordance with Section 9.2(c) or (d),
pursuant to a bona fide offer (a "Selling  Member"),  such  Selling  Member will
provide notice of such proposed transfer (including the identity of the proposed
purchaser of such  interest  and the  proposed  terms  thereof)  (the  "Transfer
Notice"), at least fifteen (15) Business Days prior to the proposed transfer, to
each other Member, whereupon each other Member shall have the right to purchase,
at the same  price  and upon the same  terms  and  conditions  set  forth in the
Transfer  Notice,  a pro rata portion of such interest  based upon such Member's
portion of the  Percentage  Interests held by all Members other than the Selling
Member.  The  purchase  price  shall be payable  in cash.  In the event that the
Transfer  Notice  specifies the payment of  consideration  other than cash,  the
purchase price for purposes of this Section 9.2(a) shall be the cash  equivalent
of such  consideration,  determined  by the Board in good  faith.  The  Transfer
Notice shall  constitute an  irrevocable  offer by the Selling Member to sell to
the other  Members such  interests at the price and on the terms as contained in
such Transfer Notice. Each Member desiring to participate in such purchase shall
provide the Selling  Member and each other  Member  notice of its  agreement  to
participate  (the  "Participation  Notice")  within  ten (10)  Business  Days of
receipt of the Transfer Notice specifying such participation and whether and the
extent to which such Member wishes to acquire any remaining, unallocated portion
of the proposed transfer (the "Unallocated  Portion").  In the event that one or
more of the other Members does not provide a timely  Participation  Notice,  the
Unallocated  Portion shall be allocated in pro rata proportion to the Percentage
Interest held by each of the Members who submits a  Participation  Notice to the
extent of such Member's indicated willingness to acquire any Unallocated Portion
as provided in such Members'  Participation  Notice.  The  Participation  Notice
shall be deemed to be an  irrevocable  commitment  to purchase  from the Selling
Member at the price on the terms as contained in the Transfer  Notice the amount
of the interests that such Member specifies in the Participation  Notice. In the
event that the Members are not willing to purchase all of the interests  offered
pursuant to the Transfer  Notice and the amount of  interests  which the Selling
Member has offered to sell  pursuant to the  Transfer  Notice less the amount of
interests the Members are willing to accept,  is less than the minimum amount of
interests  which the  offeror is willing to  purchase  pursuant to the bona fide
offer described in the Transfer Notice, then the Members shall be deemed to have
rejected  the offer  contained in the Transfer  Notice in its  entirety.  In the
event that the Members shall have accepted all or part of the interests  offered
pursuant to the Transfer Notice (and shall not have been deemed to have rejected
the offer in its entirety as described in the immediately  preceding  sentence),
then the Selling  Member shall sell to such Members such  interests as have been
accepted by such Members as specified in such Member's  Participation  Notice on
the terms  contained  in the  Transfer  Notice.  Any  interests  not sold to the
Members  pursuant  to the  preceding  sentence  may be sold  to a  third  party,
including  the original  offeror,  at a price not lower than,  and on such other
terms  and  conditions  not more  favorable  to such  third  party  than,  those
contained in the original Transfer Notice, at any time within 180 days after the
expiration  of the  offer  required  by this  Section  9.2(a).  In the event the
interests are not  transferred  by the Selling  Member on such terms during such
180-day  period,  the  restrictions  of this  Section  9.2(a) shall again become
applicable to any transfer of interests by the Selling Member.

(b) Tag Along Rights.

     (i) General. No Selling Member may transfer (other than pursuant to Section
     9.2(c) or 9.2(d)) to any Person  Membership  Interests held by such Selling
     Member,  unless the terms and  conditions of such transfer shall include an
     offer by the third party  transferee  to the other  Members  (each,  a "Tag
     Along Participant"),  at a price calculated using methodology substantially
     similar  to the  methodology  used to  calculate  the price of the  Selling
     Member's  Membership  Interest  taking into  account the  relative  capital
     accounts and distribution  rights of the Tag Along  Participants  (the "Tag
     Along Price") and on the same terms and  conditions  as the Selling  Member
     has agreed to sell its Membership  Interest,  to include in the transfer to
     the third party transferee a portion of Membership  Interests determined in
     accordance with this Section 9.2(b).

     (ii)  Obligation of Transferee to Purchase.  The  transferee of the Selling
     Member shall purchase from each Tag Along  Participant  the portion of such
     Tag Along Participant's Membership Interest that such Tag Along Participant
     desires to sell, provided that such portion does not exceed the Maximum Tag
     Along Portion (as defined  below) and, if such portion  exceeds the Maximum
     Tag Along Portion, the transferee shall purchase only the Maximum Tag Along
     Portion.  For purposes hereof, the term "Maximum Tag Along Portion" means a
     portion of a Tag Along Participant's Membership Interest the price of which
     (based on the Tag Along Price of such Membership Interest) equals the total
     original  price  proposed  to be paid  by the  transferee  for the  Selling
     Member's  Membership  Interest  multiplied by a fraction,  the numerator of
     which  is the Tag  Along  Price  of  such  portion  which  such  Tag  Along
     Participant desires to include in such sale and the denominator of which is
     the aggregate Tag Along Price of the Membership  Interests that the Selling
     Member and each Tag Along Participant desire to include in such sale.

     (iii)  Notice.  In the event the Selling  Member  proposes to transfer  any
     Membership  Interest in a  transaction  subject to this  Section,  it shall
     notify, or cause to be notified,  in writing, each Tag Along Participant of
     each such proposed transfer. Such notice (the "Sale Notice") shall be given
     not more than 60 nor less than 20 calendar  days prior to the proposed sale
     date and set  forth:  (i) the  name of the  transferee  and the  Membership
     Interest  proposed to be transferred,  (ii) the proposed amount and form of
     consideration and terms and conditions of payment offered by the transferee
     (the  "Transferee  Terms"),  (iii) that the transferee has been informed of
     the "tag  along  right"  provided  for in this  Section,  and has agreed to
     purchase Membership Interests from each Tag Along Participant in accordance
     with the terms hereof, and (iv) the proposed sale date.

     (iv)  Exercise.  The  tag-along  right may be exercised  by each  Tag-Along
     Participant by delivery of a written notice to the Selling Member (the "Tag
     Along  Notice")  within 15  calendar  days  following  receipt  of the Sale
     Notice.  The Tag Along  Notice  shall  state the  portion  of a  Membership
     Interest that such Tag Along Participant wishes to include in such transfer
     to the  transferee.  Upon the giving of a Tag Along Notice,  such Tag Along
     Participant  shall be  entitled  and  obligated  to sell the portion of its
     Membership Interest set forth in the Tag Along Notice, to the transferee on
     the  Transferee  Terms;  provided,  however,  the Selling  Member shall not
     consummate  the  sale  of  any  Membership  Interest  offered  by it if the
     transferee does not purchase all Membership  Interests which each Tag Along
     Participant  is  entitled  and  desires  to  sell  pursuant  hereto.  After
     expiration  of  the  15  calendar-day  period  referred  to  above,  if the
     provisions of this Section have been  complied  with in all  respects,  the
     Selling  Member and each Tag Along  Participant  that delivered a Tag Along
     Notice shall  transfer the  Membership  Interests  determined in accordance
     with Section  9.2(b)(ii) to the transferee on the  Transferee  Terms on the
     sale date proposed in the Sale Notice (or such other date within sixty (60)
     days of such proposed sale date as may be agreed among the  participants in
     such transfer).

     (v)  Several   Liability.   Anything  to  the  contrary   contained  herein
     notwithstanding, the Selling Member agrees to use its reasonable good faith
     efforts to seek to ensure that the applicable  Transferee Terms provide for
     several, and not joint, liability,  with respect to the indemnification and
     comparable obligations contained within such Transferee Terms.

(c) Subject to Sections  9.2(e),  (f) and (g), a Member may at any time and from
time to time (i) transfer all or part of such  Member's  Membership  Interest to
any of such Member's Family Members, (ii) transfer all or part of its Membership
Interest to its members, partners,  shareholders or other equity holders, as the
case may be  ("Distributee"),  or (iii)  transfer  all or part of such  Member's
Membership Interest to a wholly-owned subsidiary of such Member;  provided, that
such  Member  and  subsidiary  agree  with the  Company  in  writing  that  such
subsidiary  shall  transfer  such  Membership   Interest  back  to  such  Member
immediately  upon such subsidiary  ceasing to be wholly-owned by such Member.  A
Member  may at any  time  and  from  time  to time  pledge  or  hypothecate,  in
connection with its bona fide financing arrangements (including,  in the case of
Motient, under its current guaranteed bank facilities), its Membership Interest,
provided,   that  upon   foreclosure  or  other   execution  of  the  pledge  or
hypothecation,  any assignment or transfer shall be subject to Sections  9.2(e),
(f) and (g).  Subject to Sections  9.2(e),  (f) and (g), an Investor  may at any
time and from time to time  transfer all or part of its  Membership  Interest to
another Investor.

(d) Motient shall have the right subject to Sections 9.2(a),  (e), (f), and (g),
to assign or transfer  its  interest in the Company to any Person  owning 10% or
more of the outstanding common stock of Motient.

(e) In  addition  to any other  requirements  of this  Agreement  relating  to a
transfer of Membership Interests, no Membership Interest shall be transferred or
assigned  unless the transferee (i) executes an instrument  satisfactory  to the
Board  accepting all of the terms and conditions  relating to a Member set forth
in this Agreement,  (ii) pays any reasonable expenses of the Company incurred in
connection  with such transfer or  assignment  (including,  without  limitation,
attorney's  fees) and (iii) is either an  "accredited  investor"  (as defined in
Rule  501  promulgated  under  the  Securities  Act of  1933,  as  amended  (the
"Securities  Act")) or provides an opinion of counsel  reasonably  acceptable to
the Company that the transfer will not require registration under the Securities
Act.

(f) Notwithstanding any other provisions of this Agreement to the contrary,  the
Board may prohibit any proposed transfer if, in the reasonable  determination of
the Board,  such transfer would (i) result in the close of the Company's taxable
year with respect to all Members,  in the  termination of the Company within the
meaning of Section  708(b) of the Code or in the  termination of its status as a
partnership  under the Code,  (ii) cause the Company to be in  violation  of any
applicable  state or Federal  securities  laws or (iii) result in an interest in
the Company being held by a Person whose  participation  in the ownership of the
Company would be detrimental to the Company.

(g) To the extent that any regulatory approval, notification or other submission
or procedure is required or customarily provided in connection with the exercise
of any right or  obligations  as set forth in this Agreement with respect to the
transfer or assignment of interests in the Company  (including,  but not limited
to, FCC  approvals  (if  required),  Hart-Scott-Rodino  filings  and  applicable
securities laws), such transfer or assignment pursuant to this Agreement will be
delayed  and will only take place  after such  approval,  notification  or other
submission or procedure has been obtained, submitted or completed.

(h) Any transfer of Membership  Interests hereunder shall be deemed to include a
proportional  transfer of the  transferor's  Units and  Capital  Account and the
transferee  shall  be  deemed  to  have  received  all  prior   allocations  and
distributions  with respect to the  transferred  Capital Account for purposes of
Articles VII and VIII.

(i) Notwithstanding any other provision of this Agreement, (1) upon any transfer
of  Investor  Units and  Membership  Interest  by an  Investor to Motient or any
Affiliate  thereof or (2) if any Investor Units otherwise become held by Motient
or any Affiliate thereof, except with the prior written consent of the Investors
other than the transferring  Investor,  none of Motient or any Affiliate thereof
shall be deemed to be an  Investor  or shall be  entitled to vote as an Investor
and the Investor Units so acquired or held shall automatically  convert into the
number  of  Common  Units  which  at the  time of  such  conversion  equals  the
Percentage Interest represented by the Investor Units so acquired.

Section 9.3 Admission of Substituted Members.

(a) An  assignee  or  transferee  of an  interest  in the  Company  shall not be
admitted  to the  Company as a  substituted  Member  until (i) such  assignee or
transferee and  transferring  Member has complied with all of the conditions and
procedures set forth in Section 9.2 and (ii) payment of any reasonable  expenses
of the Company  incurred in connection with such admission  (including,  without
limitation, attorney's fees). Such assignee or transferee shall automatically be
admitted to the Company as a Member following  satisfaction of the provisions of
this Section 9.3(a).

(b) A Person who acquires any interests of a Member  pursuant to Section 9.2 but
who is not admitted as a substituted  Member pursuant to Section 9.3(a) shall be
entitled only to  allocations  and  distributions  with respect to such acquired
interests  in  accordance  with this  Agreement,  but shall have no right to any
information  or accounting of the affairs of the Company,  shall not be entitled
to inspect  the books or records of the Company and shall not have any rights of
a Member under the Delaware Act or this Agreement.

(c) A transferor of interests  shall remain a Member of the Company with respect
to such  transferred  interests  until such time, if ever, as the  transferee of
such  interests  is admitted as a  substituted  Member in  accordance  with this
Agreement.

Section 9.4  Admission of  Additional  Members.  A Person  (other than a current
Member) who purchases from the Company  interests issued pursuant to Section 9.1
shall be admitted to the Company as an Additional  Member upon furnishing to the
Company (a) a subscription  agreement,  in form satisfactory to the Board, which
agreement  shall  include  an  acceptance  by such  Person  of all the terms and
conditions of this  Agreement,  and (b) such other  documents as the Board deems
necessary or advisable.  Such admission shall become  effective on the date that
the Board determines that such conditions have been satisfied.

Section 9.5 Conversion; Drag Along Rights.

(a) At any time  prior to the  Investor  Option  Closing,  upon the  consent  of
Motient and Investors holding a majority of the Percentage Interests held by all
Investors,  and at any time after the Investor Option Closing, upon the approval
of the Board,  the Company shall be converted  into  corporate form ("Newco") by
merger,  statutory conversion or any other method set forth in such consent (the
"Conversion").  If the  Conversion  is in  connection  with  an  initial  public
offering of the  Company's  (or its  successor's)  securities,  the  outstanding
interests  in the  Company  shall be  converted  into  common  stock of Newco in
accordance  with  the  Percentage  Interests   represented  by  such  Membership
Interests,  and each  holder of such  interests  shall take such steps as may be
reasonably  requested  by the Company in  connection  therewith,  whereupon  the
rights and obligations of the Members hereunder,  including, without limitation,
Section 5.2 and Article 6, shall cease and have no further force and effect.  If
a  Conversion  is approved  for any  purpose  other than in  connection  with an
initial public offering of the Company's (or its  successor's)  securities,  (i)
the  respective  outstanding  interests of the Company  shall be converted  into
securities of Newco which track, as closely as practicable, the economic, voting
and other rights represented by such outstanding  interests immediately prior to
the  Conversion  and (ii) the  holders  of such  interests  shall  enter  into a
shareholders   agreement  and  such  other  agreements  and  the  organizational
documents of Newco will contain such  provisions as may be  necessary,  to allow
Newco to mimic,  as closely as  practicable,  the governance and other operating
provisions of this Agreement, including, without limitation, an agreement by all
shareholders  holding  stock with  special  voting,  economic or other rights to
convert such stock into common  stock  immediately  prior to the initial  public
offering of Newco  securities  on a basis  similar to that  contemplated  by the
second  sentence of this Section 9.5(a).  To the extent  permitted by applicable
law  (including  without  limitation,  Section  18-209 of the Delaware Act), the
consents  of  Members or the Board,  as the case may be,  required  by the first
sentence of this Section 9.5(a) shall be the only consents of Members  necessary
for the Company to effect a  Conversion  and no other class votes or consents of
Members shall be required in connection therewith.

(b) At any time  after the  Investor  Option  Closing,  if  Investors  holding a
majority of the Percentage Interests held by all Investors determine to transfer
or exchange (in a merger,  business combination or otherwise) in one or a series
of related bona fide arm's-length  transactions  (collectively,  the "Drag-Along
Transaction") to an unrelated and unaffiliated third party all of the Membership
Interests held by such Investors, then, upon thirty (30) days' written notice to
the other Members and the Company (the "Drag-Along Notice"),  which notice shall
include   reasonable  details  of  the  proposed   transaction,   including  the
consideration  to be received by the  Members,  each other  Member and holder of
interests  in the Company  shall be obligated  to, and shall sell,  transfer and
deliver,  or cause to be sold,  transferred and delivered,  to such third party,
all of its  interests  in the  Company in the same  transaction  at the  closing
thereof (and will deliver such interests free and clear of all liens, claims, or
encumbrances except this Agreement) (or shall vote in favor of or consent to any
transaction  requiring  the vote or consent  of  Members),  and shall  otherwise
cooperate in the consummation of such  transaction,  and the consideration to be
paid to the Members  shall  either (x) take into  account the  relative  capital
accounts and  distribution  rights of such Members or (y) be based solely on the
respective Percentage Interests held by such Members; provided, that, unless the
consideration  to be received by the Members is based  solely on the  respective
Percentage  Interests held by such Members,  (i) until the second anniversary of
the date of the  Investor  Option  Closing,  the  consent of  Members  holding a
majority of the Common  Units shall be required  with  respect to any Drag Along
Transaction in which the value of the aggregate  consideration to be paid to the
Investors  for their  interests  in the Company is less than an amount  equal to
twice the sum of such Investors' aggregate Capital  Contributions and (ii) after
the second anniversary of the date of the Investor Option Closing, Motient shall
have thirty (30) days from receipt of the Drag Along Notice to make,  or cause a
third  party  to  make,  a bona  fide  offer  that is no less  favorable  to the
Investors and the other Members than the terms,  conditions and consideration of
the Drag Along Transaction  described in the Drag Along Notice and which will be
consummated within thirty (30) days after such offer is made.

Section 9.6 Company  Registration  Rights. Upon an Initial Public Offering,  the
Company shall grant to each of the Members customary  registration rights in the
securities of the Company  commensurate with such Member's Percentage  Interest,
provided,  that such rights  shall not be  exercisable  in  connection  with the
Initial Public Offering itself.

ARTICLE X

                                BOOKS AND RECORDS

Section 10.1 Books, Records and Financial Statements.

(a) At all times  during the  continuance  of the  Company,  the  Company  shall
maintain  separate  books of account for the Company  that shall show a true and
accurate  record of all costs and  expenses  incurred,  all  charges  made,  all
credits  made  and  received  and all  income  derived  in  connection  with the
operation  of the  Company  business,  in  accordance  with  generally  accepted
accounting  principles  consistently applied to the extent not inconsistent with
this  Agreement.  Such books of account,  together with a copy of this Agreement
and of the  Certificate  of  Formation,  shall at all times be maintained at the
principal  place of  business of the Company (or at the place of business of the
Person to whom the duty to maintain these books has been delegated in accordance
herewith  and  identified  in  writing  to the  Members)  and  shall  be open to
inspection  and  examination  at  reasonable  times by each  Member and its duly
authorized  representative  for any purpose  reasonably related to such Member's
interest as a member of the Company.

(b)  The  Board  shall  prepare  and  maintain,  or  cause  to be  prepared  and
maintained,  the  books of  account  of the  Company.  The  following  financial
information,  which shall be certified  to by an  independent  certified  public
accountant,  shall be  transmitted by the Company to each Member within four (4)
months after the close of each Fiscal Year:

     (i)  balance  sheet of the  Company as of the  beginning  and close of such
     Fiscal Year;

     (ii) statement of Company profits and losses for such Fiscal Year;

     (iii)  statement of such Member's  Capital  Account as of the close of such
     Fiscal Year, and changes therein during such Fiscal Year; and

     (iv)  statement  indicating  such  Member's  share of each item of  Company
     income, gain, loss, deduction or credit for such Fiscal Year for income tax
     purposes.

(c) Within  three (3) months  after the close of each Fiscal  Year,  the Company
shall  send to each  Member  a Form  K-1 tax  statement  or any  successor  form
thereto.

(d) The Board shall prepare,  or cause to be prepared,  such other statements as
it deems necessary or advisable.

Section 10.2 Accounting  Method.  For both financial and tax reporting  purposes
and for purposes of determining profits and losses, the books and records of the
Company  shall  be  kept  on the  accrual  method  of  accounting  applied  in a
consistent manner and shall reflect all Company  transactions and be appropriate
for the Company's business.

Section 10.3 Audit. The financial  statements of the Company shall be audited at
the end of  each  Fiscal  Year by an  independent  certified  public  accountant
selected  by the Board,  with such audit to be  accompanied  by a report of such
accountant containing its opinion. The cost of such audits will be an expense of
the Company.  A copy of any such audited  financial  statements and accountant's
report will be made available for inspection by the Members.

ARTICLE XI

                                   TAX MATTERS

Section 11.1 Tax Matters  Partner.  Motient is hereby  designated as the initial
"Tax Matters  Partner" of the Company for purposes of Section  6231(a)(7) of the
Code and shall have the power to manage and  control,  on behalf of the Company,
any tax  audit  or  administrative  proceeding  at the  Company  level  with the
Internal  Revenue Service  relating to the  determination of any item of Company
income,  gain,  loss,  deduction  or credit for  federal  income  tax  purposes;
provided,  however,  that the Tax Matters Partner shall not settle any tax audit
or administrative  proceeding  without the consent of the affected Members.  The
Tax Matters  Partner shall be fully  indemnified by the Company for all expenses
incurred  by the Tax  Matters  Partner  with  respect  to any such tax  audit or
administrative proceeding. The Tax Matters Partner may be replaced by the Board.

Section 11.2 Section 754 Election.  Upon the  reasonable  request of any Member,
the Tax  Matters  Partner,  shall  make or revoke an  election  on behalf of the
Company,  in accordance  with Section 754 of the Code, so as to adjust the basis
of Company property in the case of a distribution of property within the meaning
of Section 734 of the Code, and in the case of a transfer of a Company  interest
within the meaning of Section 743 of the Code.  Each Member shall,  upon request
of the Tax Matters Partner,  supply the information  necessary to give effect to
such an election.

Section 11.3 Taxation as  Partnership.  The Members intend that the Company will
be treated as a  partnership  for U.S.  federal  income tax purposes and, to the
extent permitted under applicable law, all other income tax purposes.

ARTICLE XII

                   LIABILITY, EXCULPATION AND INDEMNIFICATION

Section 12.1 Liability.

(a) Except as otherwise provided by the Delaware Act, the debts, obligations and
liabilities  of the Company,  whether  arising in contract,  tort or  otherwise,
shall be solely the debts,  obligations and  liabilities of the Company,  and no
Covered Person shall be obligated  personally  for any such debt,  obligation or
liability of the Company solely by reason of being a Covered Person.

(b) Except as otherwise  expressly required by law, a Member, in its capacity as
Member,  shall  have no  liability  in excess of (a) the  amount of its  Capital
Contributions,  (b) its share of any  assets  and  undistributed  profits of the
Company,  (c) its  obligation to make other payments  expressly  provided for in
this Agreement,  and (d) the amount of any distributions  wrongfully distributed
to it.

Section 12.2 Exculpation.

(a) No Covered Person shall be liable to the Company or any other Covered Person
for any  loss,  damage  or  claim  incurred  by  reason  of any act or  omission
performed,  or omitted to be performed,  by such Covered Person in good faith on
behalf of the Company and in a manner reasonably believed to be within the scope
of authority  conferred on such Covered Person by this Agreement,  except that a
Covered  Person shall be liable for any such loss,  damage or claim  incurred by
reason of such Covered Person's willful  misconduct,  fraud, gross negligence or
breach of this Agreement.

(b) A Covered Person shall be fully  protected in relying in good faith upon the
records  of  the  Company  and  upon  such  information,  opinions,  reports  or
statements  presented  to the  Company by any Person as to matters  the  Covered
Person reasonably believes are within such other Person's professional or expert
competence and who has been selected with reasonable care by or on behalf of the
Company, including information,  opinions, reports or statements as to the value
and amount of the  assets,  liabilities,  profits,  losses,  or any other  facts
pertinent  to the  existence  and amount of assets from which  distributions  to
Members might properly be paid.

Section 12.3 Indemnification.

(a) To the fullest extent permitted by applicable law, each Covered Person shall
be entitled to indemnification  from the Company for any loss, damage,  claim or
liability  incurred  by such  Covered  Person by  reason of any act or  omission
performed,  or omitted to be performed,  by such Covered Person in good faith on
behalf of the Company and in a manner reasonably believed to be within the scope
of authority conferred on such Covered Person by this Agreement,  except that no
Covered  Person  shall be  entitled  to be  indemnified  in respect of any loss,
damage,  claim or liability incurred by such Covered Person by reason of willful
misconduct,  fraud, gross negligence or breach of this Agreement with respect to
such acts or omissions; provided, however, that any indemnity under this Section
12.3 shall be provided out of and to the extent of Company  assets only,  and no
Covered Person shall have any personal liability on account thereof.

(b) If any claim shall be asserted against a Covered Person, in respect of which
such Covered Person proposes to demand  indemnification  under this Section 12.3
from the Company,  such  Covered  Person shall notify the Company to that effect
with reasonable promptness after such assertion,  and the Company shall have the
right to assume the  entire  control of the  defense or  settlement  of any such
claim,  through  its  own  attorneys  and at  its  expense,  and  in  connection
therewith,  such Covered Person shall  cooperate  fully to make available to the
Company all information under its control relating thereto.

(c) All rights to indemnification  provided herein shall survive the termination
of this  Agreement  and the  withdrawal,  removal or  insolvency  of any Member;
provided, that a claim for indemnification  hereunder is made by or on behalf of
the Covered Person seeking such  indemnification  prior to the time distribution
in liquidation of the assets of the Company is made pursuant to Article XIV.

(d) The Board and the Company may enter into  indemnity  contracts  with Covered
Persons and adopt written procedures pursuant to which arrangements are made for
the  advancement of expenses and the funding of  obligations  under Section 12.4
and  containing  such  other  procedures   regarding   indemnification   as  are
appropriate.

Section  12.4  Expenses.  To the fullest  extent  permitted by  applicable  law,
expenses  (including  legal fees)  incurred by a Covered Person in defending any
claim, demand,  action, suit or proceeding shall, from time to time, be advanced
by the Company prior to the final  disposition  of such claim,  demand,  action,
suit or proceeding upon receipt by the Company of an undertaking by or on behalf
of the Covered  Person to repay such amount if it shall be  determined  that the
Covered  Person is not entitled to be  indemnified as authorized in Section 12.3
hereof.

Section 12.5 Insurance.  The Company may purchase and maintain insurance, to the
extent and in such  amounts  as the Board  shall  deem  advisable,  on behalf of
Covered Persons and such other Persons as the Board shall determine, against any
liability  that may be asserted  against or expenses that may be incurred by any
such  Person  in  connection   with  the  activities  of  the  Company  or  such
indemnities, regardless of whether the Company would have the power to indemnify
such Person against such liability under the provisions of this Agreement.

Section 12.6 Outside  Businesses.  The parties  acknowledge that Covered Persons
have and may in the future  have  investments  in other  businesses  that may be
similar  to  or   competitive   with  the  Company   (collectively,   "Competing
Businesses")  independent of their investments in the Company.  By virtue of its
rights under this Section or by having  individuals  designated by it serving on
the Board, no Covered Person shall have any obligation to the Company to refrain
from making  investments in Competing  Businesses,  or otherwise engaging in any
commercial activity;  and neither the Company nor any other Covered Person shall
have any right with respect to any such investments or activities  undertaken by
such Covered Person.  Without  limitation of the foregoing,  each Covered Person
may engage in or possess an interest in other business ventures of any nature or
description, independently or with others, similar or dissimilar to the business
of the  Company,  and the Company and the other  Covered  Persons  shall have no
rights or expectancy by virtue of such Covered Person's  relationships  with the
Company,  this Agreement or otherwise in and to such independent ventures or the
income or profits derived therefrom;  and the pursuit of any such venture,  even
if such investment is in a Competing  Business,  shall not be deemed wrongful or
improper.  No  Covered  Person  shall be  obligated  to present  any  particular
investment opportunity to the Company even if such opportunity is of a character
that, if presented to the Company,  could be pursued by the Company, and Covered
Persons  shall  continue  to have the  right to take for  their  own  respective
account or to recommend to others any such  particular  investment  opportunity.
The  provisions of this Section 12.6 shall in no way limit or eliminate  Covered
Persons'   duties,   responsibilities   and  obligations  with  respect  to  any
proprietary  information of the Company,  including any  applicable  duty not to
disclose or use such proprietary  information  improperly or obtain therefrom an
improper personal benefit.

ARTICLE XIII

                    DISSOLUTION, LIQUIDATION AND TERMINATION

Section 13.1  Dissolution.  The Company shall be dissolved and its affairs shall
be wound up upon the first to occur of any of the following:

(a)      the unanimous consent of the Members; or

(b)      the consent of the Members in accordance with Section 5.2; or

(c) the consent of the Required  Investor Majority upon the occurrence of any of
the following  events:  (i) the lapse,  termination,  or  non-renewal  of any of
Services licenses in effect with the Federal Communications Commission such that
it is  commercially  unreasonable  to  continue  the  business  of  Services  as
currently  conducted,  or (ii) a full or partial but material  casualty event to
the Satellite (as defined in the Asset Sale  Agreement),  or (iii) a transaction
of the type contemplated by Section 8.9 of the Asset Sale Agreement, or (iv) the
Bankruptcy  of Motient or Services or (v) a breach by Motient or Services  under
the Investment  Agreement or any of the Ancillary  Agreements which is not cured
within the specified grace or cure period; or

(d) the entry of a decree of judicial  dissolution  under Section  18-802 of the
Delaware Act.

Section 13.2 Notice of  Dissolution.  Upon the  dissolution of the Company,  the
Board shall promptly notify the Members of such dissolution.

Section 13.3 Liquidation. Upon dissolution of the Company, the Board or, if such
dissolution  has  occurred in  accordance  with  Section  13.1(c),  the Required
Investor  Majority  shall  appoint a liquidating  trustee who shall  immediately
commence to wind up the Company's affairs; provided,  however, that a reasonable
time shall be allowed for the orderly  liquidation  of the assets of the Company
and the  satisfaction of liabilities to creditors so as to enable the Members to
minimize the normal  losses  attendant  upon a  liquidation.  The Members  shall
continue to share Profits and Losses during liquidation in the same proportions,
as  specified  in Article VII hereof,  as before  liquidation.  The  proceeds of
liquidation shall be distributed, as realized, in the following descending order
of priority to the extent permitted under applicable law:

     (i) First,  to creditors of the Company,  including  Members,  in the order
     provided by law and

     (ii)  Thereafter,  to the  Members in  accordance  with the  provisions  of
     Article 8 hereof; provided,  however, that in the event of a dissolution of
     the Company in accordance  with Section  13.1(c) hereof and at the election
     of the  Investors,  all or a portion of the  amounts  distributable  to the
     Members  pursuant  to  Article  8 hereof  shall be paid in kind with the IP
     Assets. Amounts otherwise  distributable to the Members pursuant to Article
     8 hereof  shall be  reduced  by the fair  market  value of the IP Assets as
     agreed to by the Members and if such agreement cannot be reached,  the fair
     market value as determined by an independent appraisal.

Section 13.4 Termination.  The Company shall terminate when all of the assets of
the Company  have been  distributed  in the manner  provided for in this Article
XIV, and the  Certificate  of Formation  shall have been  canceled in the manner
required by the Delaware Act.

Section 13.5 Claims of the Members.  The Members and former  Members  shall look
solely to the Company's  assets for the return of their  Capital  Contributions,
and if the assets of the Company remaining after payment of or due provision for
all debts, liabilities and obligations of the Company are insufficient to return
such  Capital  Contributions,  the  Members  and  former  Members  shall have no
recourse against the Company or any other Member.

ARTICLE XIV

                                   AMENDMENTS

Section 14.1  Amendments.  Any amendments to this Agreement shall be adopted and
be effective as an amendment  hereto (a) prior to the Investor  Option  Closing,
only if approved by Motient and the Required Investor Majority and (b) following
the Investor Option Closing,  only if approved by the Required Investor Majority
and,  if such  amendment  would  adversely  effect  the  particular  rights  and
interests of Motient disproportionately to the adverse effects of such amendment
on the rights and interests of other Members, Motient;  provided,  however, that
no provision of this  Agreement  which  establishes a class vote and/or  minimum
Percentage  Interest required to take any action shall be amended in any respect
which would reduce such voting requirement, unless such amendment is approved by
such  class(es)  and/or Members  holding at least the  Percentage  Interest that
would have been  required  to take the action  permitted  to be taken  under the
provision to be amended.

ARTICLE XV

                                  MISCELLANEOUS

Section 15.1 Further Assurances. The Members shall cooperate with each other and
the Company and shall promptly execute,  acknowledge and deliver any assurances,
approvals or documents  reasonably  requested by a Member that is necessary  for
the  requesting  Member or the Company to satisfy its  obligations  hereunder or
obtain the benefits contemplated hereby.

Section 15.2 Notices.  All notices  provided for in this  Agreement  shall be in
writing,  duly signed by the party  giving such  notice,  and shall be delivered
personally,  sent by a nationally  recognized  overnight courier,  telecopied or
mailed by registered or certified mail, as follows:

(a) If given to the Company, at the Company's mailing address set forth below:

                           Motient Satellite Ventures LLC
                           10802 Parkridge Boulevard
                           Reston, Virginia  20191-5416
                           Fax:  (703) 758-6134
                           Attention:       Randy S. Segal, Esq.

                           with a copy to:

                           Motient Satellite Ventures LLC
                           211 North Union Street, Suite 300
                           Alexandria, Virginia  22314
                           Fax:  (703) 706-3801
                           Attention:       Hal Perkins, Esq.

                  with a copy to each Member as set forth in clause (b) below.

(b) If given to any Member, at the address set forth on Schedule I hereof (or as
modified from time to time by a Member upon written notice to the Company).

                  Notices  delivered  personally  to an  addressee  or  sent  by
overnight courier shall be deemed to have been given upon such delivery. Notices
sent by  telecopier  shall be deemed to have been  given  upon  confirmation  by
telecopy  answerback  (provided  that the sending of any such notice is followed
promptly  by the  mailing of the  original of such  notice).  Notices  mailed by
registered  or  certified  mail  shall be  deemed to have  been  given  upon the
expiration of five (5) days after such notice has been deposited in the mail.

Section  15.3  Failure  to Pursue  Remedies.  The  failure  of any party to seek
redress  for  violation  of, or to insist  upon the strict  performance  of, any
provision of this Agreement shall not prevent a subsequent act, which would have
originally  constituted  a  violation  from  having  the  effect of an  original
violation.  No waiver of any breach of any of the terms of this Agreement  shall
be effective  unless such waiver is in writing and signed by the Member  against
whom such waiver is claimed.

Section  15.4  Cumulative  Remedies.  The rights and  remedies  provided by this
Agreement  are  cumulative  and the use of any one  right or remedy by any party
shall not  preclude  or waive its right to use any or all other  remedies.  Said
rights and  remedies  are given in addition to any other  rights the parties may
have by law, statute, ordinance or otherwise.

Section 15.5 Binding  Effect.  This Agreement shall be binding upon and inure to
the  benefit  of  all of the  parties  and,  to the  extent  permitted  by  this
Agreement, their successors, legal representatives and assigns.

Section 15.6 Severability.  The invalidity or unenforceability of any particular
provision of this Agreement shall not affect the other  provisions  hereof,  and
this  Agreement  shall  be  construed  in all  respects  as if such  invalid  or
unenforceable provision were omitted.

Section  15.7  Counterparts.  This  Agreement  may be  executed in any number of
counterparts  with the same effect as if all parties  hereto had signed the same
document.  All counterparts shall be construed together and shall constitute one
instrument.

Section  15.8  Integration.  This  Agreement  and  the  Subscription  Agreements
constitute  the entire  agreement  among the parties  hereto  pertaining  to the
subject  matter  hereof and  thereof  and  supersede  all prior  agreements  and
understandings pertaining thereto.

Section  15.9  Governing  Law.  This  Agreement  and the  rights of the  parties
hereunder  shall be  interpreted  in  accordance  with the laws of the  State of
Delaware,  and all rights and  remedies  shall be governed by such laws  without
regard to principles of conflict of laws.

                                      * * *

<PAGE>

                            SEPARATE SIGNATURE PAGE
              FIRST AMENDED AND RESTATED LIMITED LIABILITY COMPANY
                               AGREEMENT OF NEWCO

         IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as
of the date first above written.

                                     MOTIENT CORPORATION

                                     By:  /s/Gary M. Parsons
                                          Gary M. Parsons, Chairman

<PAGE>

                            SEPARATE SIGNATURE PAGE
              FIRST AMENDED AND RESTATED LIMITED LIABILITY COMPANY
                               AGREEMENT OF NEWCO

         IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as
of the date first above written.

                                      TELCOM SATELLITE VENTURES INC.

                                      By:  /s/Rahul Prakash
                                           Name:  Rahul Prakash
                                           Title: President

<PAGE>

                            SEPARATE SIGNATURE PAGE
              FIRST AMENDED AND RESTATED LIMITED LIABILITY COMPANY
                               AGREEMENT OF NEWCO

         IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as
of the date first above written.

                                     COLUMBIA SPACE (QP), INC.

                                      By:  /s/James B. Fleming
                                           Name:  James B. Fleming
                                           Title: Managing Member

                                     COLUMBIA SPACE (AI), INC.

                                      By:  /s/James B. Fleming
                                           Name:  James B. Fleming
                                           Title: Managing Member

                                     COLUMBIA SPACE PARTNERS, INC.

                                      By:  /s/James B. Fleming
                                           Name:  James B. Fleming
                                           Title: Managing Member

<PAGE>

                            SEPARATE SIGNATURE PAGE
              FIRST AMENDED AND RESTATED LIMITED LIABILITY COMPANY
                               AGREEMENT OF NEWCO

         IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as
of the date first above written.

                                      SPECTRUM SPACE EQUITY
                                      INVESTORS IV, INC.

                                      By:  /s/Kevin J. Maroni
                                           Name:  Kevin J. Maroni
                                           Title: Chairman and CEO

                                      SPECTRUM SPACE IV PARALLELL, INC.

                                      By:  /s/Kevin J. Maroni
                                           Name:  Kevin J. Maroni
                                           Title: Chairman and CEO

                                      SPECTRUM SPACE IV MANAGERS', INC.

                                      By:  /s/Kevin J. Maroni
                                           Name:  Kevin J. Maroni
                                           Title: Chairman and CEO

<PAGE>

                                   SCHEDULE I

                              CAPITAL CONTRIBUTIONS

                                     MEMBERS
<TABLE>

<CAPTION>

                                                                      Number/          Percentage          Capital
           Name                           Address                   Type of Units       Interest          Contributions
           ====                           =======                   =============      ===========        =============

<S>                            <C>                                 <C>                      <C>                <C>
Motient Corporation            10802 Parkridge Boulevard           80 Common Units          80%                $1.00
                               Reston, Virginia 20191-5416
                               Tel:  (703) 758-6130
                               Fax:  (703) 758-6134
                               Attention: Randy S. Segal,
                               Senior Vice President and
                               General Counsel
                               With a copy to:
                               Hogan & Hartson L.L.P.
                               8300 Greensboro Drive Suite 1100
                               McLean, Virginia  22102 Tel:
                               (703) 610-6123
                               Fax:  (703) 610-6200
                               Attention:  Richard K.A.
                               Becker, Esq.
=========================      ==================================  ===============     ===========        =============
Telcom Satellite Ventures      211 North Union Street              7.2 Investor             7.2%            $18,000,000
Inc.                           Suite 300                           Units
                               Alexandria, Virginia 22314
                               Attention:  Hal B. Perkins
                               Tel:    (703) 706-3800
                               Fax:    (703) 706-3801
=========================      ==================================  ===============     ===========        =============
Columbia Space (QP), Inc.      211 North Union Street              3.01282560          3.01282560%           $7,532,064
                               Suite 300                           Investor Units
                               Alexandria, Virginia 22314
                               Attention: James Fleming

                               Tel:    (703) 519-3000
                               Fax:    (703) 519-3904
                               with a copy to:
                               Edwards & Angell, LLP
                               101 Federal Street
                               Boston, MA 02100
                               Attention:  Stephen Meredith,
                               Esq.
                               Tel:  (617) 951-2233
                               Fax:  (888) 325-9120
=========================      ==================================  ===============     ===========        =============
Columbia Space (AI), Inc.      211 North Union Street              0.00097280          0.00097280%               $2,432
                               Suite 300                           Investor Units
                               Alexandria, Virginia 22314
                               Attention: James Fleming

                               Tel:    (703) 519-3000
                               Fax:   (703) 519-3904
                               with a copy to:
                               Edwards & Angell, LLP
                               101 Federal Street
                               Boston, MA 02100
                               Attention:  Stephen Meredith,
                               Esq.
                               Tel:    (617) 951-2233
                               Fax:   (888) 325-9120

=========================      ==================================  ===============     ===========        =============

Columbia Space Partners, Inc.  211 North Union Street              3.3862016            3.3862016%           $8,465,504
                               Suite 300                           Investor Units
                               Alexandria, Virginia 22314
                               Attention: James Fleming

                               Tel:  (703) 519-3000
                               Fax:  (703) 519-3904
                               with a copy to:
                               Edwards & Angell, LLP
                               101 Federal Street
                               Boston, MA 02100
                               Attention:  Stephen
                               Meredith, Esq.
                               Tel:  (617) 951-2233
                               Fax:  (888) 325-9120

=========================      ==================================  ===============     ===========        =============
Spectrum Space Equity          One International Place
Investors IV, Inc.             29th Floor                          6.18048              6.18048%            $15,451,200
                               Boston, MA 82110                    Investor Units
                               Attention:  Kevin Maroni
                               Tel:    (617) 464-4600
                               Fax:   (617) 464-4601
                               with a copy to:
                               Edwards & Angell, LLP
                               101 Federal Street
                               Boston, MA 02100
                               Attention:  Stephen
                               Meredith, Esq.
                               Tel:   (617) 951-2233
                               Fax:  (888) 325-9120

=========================      ==================================  ===============     ===========        =============

Spectrum Space IV Parallel,    One International Place           0.14464                0.14464%               $361,600
Inc.                           29th Floor                        Investor Units
                               Boston, MA 82110
                               Attention:  Kevin Maroni
                               Tel:    (617) 464-4600
                               Fax:   (617) 464-4601

                               with a copy to:
                               Edwards & Angell, LLP
                               101 Federal Street
                               Boston, MA 02100
                               Attention:  Stephen
                               Meredith, Esq.
                               Tel:   (617) 951-2233
                               Fax:  (888) 325-9120

=========================      ==================================  ===============     ===========        =============

Spectrum Space IV Managers,    One International Place           0.07488                0.07488%               $187,200
Inc.                           29th Floor                        Investor Units
                               Boston, MA 82110
                               Attention: Kevin Maroni
                               Tel:    (617) 464-4600
                               Fax:   (617) 464-4601

                               with a copy to:
                               Edwards & Angell, LLP
                               101 Federal Street
                               Boston, MA 02100
                               Attention:  Stephen
                               Meredith, Esq.
                               Tel:   (617) 951-2233
                               Fax:  (888) 325-9120

=========================      ==================================  ===============     ===========        =============

</TABLE>EXHIBIT 10.45

                          REGISTRATION RIGHTS AGREEMENT

         REGISTRATION  RIGHTS AGREEMENT (the "Agreement")  dated  as of June 29,
2000, by and among MOTIENT CORPORATION,  a Delaware corporation (the "Company"),
each stockholder  signatory  hereto (the  "Investors") and each stockholder that
shall  become a party  hereto  pursuant to Section  12(d)  hereof after the date
hereof by executing and delivering a joinder agreement substantially in the form
of  Exhibit  A  hereto  (the  "Joinder  Agreement")  (each,  together  with  the
Investors, a "Stockholder" and, collectively, the "Stockholders").

                              Terms and Conditions

         The  Investors  have  agreed to invest in, and  provide  financing  for
Motient Satellite  Ventures LLC, a Delaware limited liability company ("Newco"),
and the Company and Newco have agreed to issue, sell and grant to the Investors,
certain securities and options pursuant to the Investment Agreement, dated as of
June  22,  2000,  by and  among  the  Company,  Newco  and  the  Investors  (the
"Investment Agreement");

         The Parties desire herein to provide certain registration rights to the
Stockholders  with respect to the shares of Common Stock that may be acquired by
the  Stockholders  pursuant to the exercise of the Parent Common Stock  Purchase
Option or the  effectuation  of the Parent  Conversions  (each as defined in the
Investment Agreement) pursuant to the Investment Agreement.

         In consideration  of the mutual  covenants and agreements  contained in
this Agreement and the Investment Agreement,  and intending to be legally bound,
the parties hereto agree as follows:

Section 1 . Definitions. As used in this Agreement, the following terms have the
meanings indicated below or in the referenced sections of this Agreement:

         "Common Stock."  The Company's Common Stock,  $.01 par value per share,
as the same may be constituted from time to time.

         "Demand Registration."  As defined in Section 4(a) hereof.

         "Exchange Act."  The Securities  Exchange Act of 1934, as amended,  and
the rules and regulations thereunder.

         "Existing   Registration   Rights   Agreements"   shall  mean  (i)  the
Registration Rights Agreement, as amended and restated on April 19, 1996, by and
among the Company,  Toronto  Dominion  Investments,  Inc.  Morgan Guaranty Trust
Company of New York and Hughes  Communications  Satellite  Services,  Inc.  (the
"Bridge   Registration  Rights  Agreement"),   (ii)  the  Amended  and  Restated
Registration  Rights Agreement,  dated as of March 31, 1998, as amended,  by and
among the Company, Hughes Electronics Corporation,  Singapore Telecommunications
Ltd., and Baron Capital Partners,  L.P. (the "Amended and Restated  Registration
Rights  Agreement"),  (iii) the Registration  Rights Agreement,  dated March 31,
1998, by and between the Company and Motorola,  Inc. (the "Motorola Registration
Rights Agreement"),  and (iv) the Exchange Agreement, dated June 7, 1999, by and
among the Company,  WorldSpace,  Inc. and XM Satellite Radio Holdings,  Inc (the
"Exchange Agreement").

         "NASD."  The National Association of Securities Dealers, Inc.

         "Person."  An  individual,  a  partnership,  a  corporation,  a limited
liability  company or  partnership,  an  association,  a joint stock company,  a
trust, a business trust, a joint venture,  an  unincorporated  organization or a
government entity or any department, agency, or political subdivision thereof.

         "Piggyback Registration."  As defined in Section 5(a) hereof.

         "Registrable  Securities."  Any shares of Common  Stock of the  Company
held by the  Stockholders,  and any shares of Common Stock that such Stockholder
has the right to acquire,  or does acquire,  upon the  conversion or exercise of
the  Parent  Common  Stock  Purchase  Option  or in  connection  with  a  Parent
Conversion (or, in either case, their  transferees) in each case pursuant to the
Investment  Agreement,  including  any shares of Common Stock issued or issuable
with  respect to such shares by reason of a stock  dividend or stock split or in
connection with a combination of shares, recapitalization, merger, consolidation
or other  reorganization;  provided,  that a Registrable Security ceases to be a
Registrable  Security  when  (i) it has  been  registered  and  sold  under  the
Securities  Act,  (ii)  it  is  sold  or  transferred  in  accordance  with  the
requirements of Rule 144 (or similar  provisions then in effect)  promulgated by
the SEC under the  Securities  Act ("Rule  144"),  or (iii) it is eligible to be
sold or transferred under Rule 144 without holding period or volume limitations.

         "Registration Expenses."  As defined in Section 8(a) hereof.
                                                 ------------

         "SEC."  The United States Securities and Exchange Commission.

          "Securities  Act."  The  Securities  Act of 1933, as amended,  and the
rules and regulations thereunder.

         "Warrant  Registration  Rights  Agreement."   The Warrant  Registration
Rights  Agreement  dated as of March 31,  1998 by and among the  Company,  Bear,
Stearns & Co., Inc., J.P. Morgan Securities Inc., T.D. Securities (USA) Inc. and
BancAmerica Robertson Stephens.

         Capitalized  terms used in this  Agreement but not defined herein shall
have the meaning ascribed to them in the Investment Agreement.

Section 2 . Securities Subject to this Agreement.

(a)  Holders  of  Registrable  Securities.  A Person is deemed to be a holder of
Registrable  Securities whenever that Person owns, directly or beneficially,  or
has  the  right  to  acquire  Registrable  Securities,  disregarding  any  legal
restrictions upon the exercise of that right.

(b) Majority of  Registrable  Securities.  As used in this  Agreement,  the term
"majority of the  Registrable  Securities"  means 51% or more of the Registrable
Securities being registered  unless the context indicates that it is 51% or more
of the Registrable Securities then issued and outstanding.

Section 3         .  S-4 Registration.
------------------   ----------------

(a) Registration.  At the request of the Investor Group Designee for an Investor
Group exercising its right to a Parent Conversion, the Company shall register on
Form S-4 (or a similar form then in effect) the Registrable  Securities acquired
in such Parent Conversion in connection with such acquisition. In addition, such
registration  statement shall also serve to cover public  reofferings or resales
of such securities (an "S-4  Registration").  The Company shall not be obligated
to effect more than one (1) S-4 Registration per Investor Group.

(b)  Effectiveness.  The  Company  shall  use its  best  efforts  to keep an S-4
Registration  continuously  effective until the earlier of one (1) year from the
consummation of the Parent Conversion to which such S-4 Registration  relates or
at such time when all of the Registrable  Securities registered pursuant thereto
are no longer Registrable Securities.

(c) Suspension; Delay in Filing.  Notwithstanding the foregoing, the Company may
delay in filing a registration statement in connection with an S-4 Registration,
may withhold efforts to cause the registration statement to become effective and
may suspend the effectiveness of the S-4 Registration, if the Company determines
in good  faith  that  such  registration  might  interfere  with or  affect  the
negotiation  or completion of any financing,  acquisition,  disposition or other
transaction or other material event that is being  contemplated in good faith by
the Company  (whether or not a final  decision has been made to  undertake  such
transaction) at the time the right to delay or suspend is exercised (a "Blackout
Period").  The Company  may  exercise  such right to delay,  suspend or withhold
efforts  not more than  twice in any twelve  (12) month  period and for not more
than ninety (90) days at a time.

         (d) Registration  Expenses.   The Company will pay for all Registration
Expenses for one (1) S-4 Registration.

         (e) Withdrawal.  To the extent the Company exercises its right to delay
filing of an S-4  Registration or withhold  efforts to cause an S-4 Registration
to become  effective,  the Company  shall  promptly  notify the  Investor  Group
Designee for the Investor  Group  requesting the S-4  Registration.  At any time
following  such notice,  the Investor Group Designee may withdraw is request for
an S-4  Registration  (whether or not in  connection  with a  withdrawal  of its
exercise of the Parent Conversion in accordance with the Investment  Agreement),
in which  case the S-4  Registration  shall not be deemed to  constitute  an S-4
Registration  and  such  Investor  Group  shall  retain  its  right  to  an  S-4
Registration  under  Section  3(a)  hereof.  In  the  event  an  Investor  Group
consummates  a Parent  Conversion  without the  benefit of an S-4  Registration,
Parent hereby agrees,  at the request of the Investor Group Designee relating to
such  Investor  Group,  to register,  as promptly as  practicable  following the
Blackout  Period,  on Form S-3 (or similar form then in effect) the  Registrable
Securities  held by such Investor Group covering  reofferings or resales of such
securities.  In  such  event,  for  such  Investor  Group,  (i)  the  term  "S-4
Registration" as used in this Agreement shall refer to such S-3 registration and
(ii) the Company  shall not be permitted  to exercise its right to  effectuate a
Blackout  Period during the 120 day period  following the  effectiveness  of the
Form S-3 Registration Statement.

Section 4.  Demand Registration.

(a) Request for Registration.  Subject to the provisions of Section 4(b), at any
time any holders of a majority of the Registrable Securities may demand that the
Company register all or part of its Registrable  Securities under the Securities
Act (a "Demand Registration");  provided,  however, that the Demand Registration
may not be exercised until after the consummation of all 3 Parent Conversions or
the exercise or lapse of the Investor Option. Within ten (10) days after receipt
of a demand,  the Company will notify in writing all Investor Group Designees of
the  demand.  Any  Investor  Group  Designee  who wants to include  any of their
Registrable  Securities of one or more of the Investors in its Investor Group in
the Demand Registration must notify the Company within ten (10) business days of
receiving  the notice of the Demand  Registration.  Except as  provided  in this
Section 4, the Company will include in the Demand  Registration  all Registrable
Securities  for which the  Company  receives  the  timely  written  demands  for
inclusion.  All demands for  inclusion  made  pursuant to this Section 4(a) must
specify  the  name  of  the  Investor  wishing  to be  included  in  the  Demand
Registration,  the number of  Registrable  Securities to be  registered  and the
intended method of disposing of the Registrable Securities.

(b) Number and Form of Registration.  The holders of the Registrable  Securities
shall be limited to one (1) Demand Registration,  which shall be on Form S-1 (or
a similar long-form  registration then in effect), or, if available on Form S-3;
provided,  however, that the Company include in the registration  statement such
Company-related disclosure as is customarily included in underwritten offerings,
or as reasonably  requested by the holders  requesting the Demand  Registration.
The Company will use commercially reasonable efforts to qualify for registration
on Form S-3.  Only Common  Stock may be included in a Demand  Registration.  The
Company shall not be obligated to effect more than one (1) underwritten offering
pursuant to the Demand Registration.

(c) Registration  Expenses.  The Company will pay all Registration  Expenses for
the Demand Registration;  provided,  however, that notwithstanding  Section 8(a)
hereto,  the Company will not be responsible for any printing costs and expenses
as  well  as  any  registration  filing  fees  in  connection  with  the  Demand
Registration;  and provided,  further,  that the Company will not be responsible
for  an  amount  of   Registration   Expenses  in  connection  with  the  Demand
Registration equal to any Registration  Expenses  previously paid by the Company
in connection with the S-4 Registrations pursuant to Section 3(d) hereto.

(d) Selection of Underwriters.  The holders  requesting the Demand  Registration
shall select the investment  banker(s) and manager(s)  that will  administer the
offering;  provided,  that such investment  banker(s) and manager(s) shall be of
recognized  national standing and the Company shall have given its prior written
consent to such  selection  (which  consent shall not be  unreasonably  delayed,
conditioned or withheld).  The Company and the holders of Registrable Securities
whose  shares are being  registered  shall enter into a  customary  underwriting
agreement with such investment banker(s) and manager(s).

(e)  Priority on Demand  Restrictions.  If the  managing  underwriter  gives the
Company and the holders of the Registrable Securities being registered a written
opinion that the number of  Registrable  Securities  requested to be included in
the Demand  Registration  exceeds the number of securities that can be sold, the
registration  will include only the number of  Registrable  Securities  that the
underwriters  believe can be sold. Subject to the priority rights of the holders
of  securities  requesting  registration  pursuant to the Existing  Registration
Rights Agreements, the number of securities registered shall be allocated, first
to the holders requesting the Demand  Registration,  and then pro rata among the
other  holders of  Registrable  Securities,  on the basis of the total number of
Registrable  Securities  requested  to  be  included  in  the  registration.  In
addition,  if the managing  underwriter shall advise the Company,  in writing or
otherwise, that an underwriters'  over-allotment option, not in excess of 15% of
the  total  offering  to be so  effected,  is  necessary  or  desirable  for the
marketing of such offering,  all Registrable Securities which are to be included
in such  offering  pursuant to this Section 4(e) shall be allocated on the basis
of the priority described in the preceding sentence.

(f) Delay in Filing.  Notwithstanding  the  foregoing,  the Company may delay in
filing a registration statement in connection with a Demand Registration and may
withhold efforts to cause the registration statement to become effective, if the
Company  determines in good faith that such registration might interfere with or
affect the negotiation or completion of any financing, acquisition,  disposition
or other transaction or other material event that is being  contemplated in good
faith by the Company (whether or not a final decision has been made to undertake
such  transaction) at the time the right to delay is exercised.  The Company may
exercise  such  right to delay or  withhold  efforts  not more than twice in any
twelve (12) month  period and for not more than ninety (90) days at a time.  If,
after a  registration  statement  becomes  effective,  the  Company  advises the
holders of registered  shares that the Company  considers it appropriate for the
registration  statement to be amended,  the holders of such shares shall suspend
any further sales of their registered shares until the Company advises them that
the registration statement has been amended. The 180-day time period referred to
in Section 7(a)(3) during which the registration  statement must be kept current
after its effective date shall be extended for an additional  number of business
days equal to the number of business  days during which the right to sell shares
was suspended pursuant to the preceding sentence.

(g) Effective Demand Registration.  A registration shall not constitute a Demand
Registration  until it has become effective and remains  continuously  effective
for the  lesser  of (i) the  period  during  which  all  Registrable  Securities
registered in the Demand Registration are sold and (ii) one hundred eighty (180)
days;  provided,  however,  that a  registration  shall not  constitute a Demand
Registration if (x) after such Demand  Registration has become  effective,  such
registration  or  the  related  offer,   sale  or  distribution  of  Registrable
Securities thereunder is interfered with by any stop order,  injunction or other
order or  requirement of the SEC or other  governmental  agency or court for any
reason not attributable to the holders requesting the Demand Registration or the
holders of Registrable Securities requesting to be included in such registration
and such  interference  is not  thereafter  eliminated  within five (5) business
days, or (y) the conditions  specified in the  underwriting  agreement,  if any,
entered into in connection  with such Demand  Registration  are not satisfied or
waived,  other than by reason of a failure on the part of the holders requesting
the Demand Registration, or (z) the number of Registrable Securities sold by the
holders in such  Demand  Registration  is less than fifty  percent  (50%) of the
number  of  Registrable  Securities  requested  to be  included  in such  Demand
Registration.

(h) Limitations on Demand  Registrations.  The Company shall not be obligated to
effect,  or take any action to effect,  a registration  pursuant to Section 4(a)
hereof if, upon  receipt of a  registration  request  pursuant  to Section  4(a)
hereof,  the  Company is advised in  writing by an  investment  banking  firm of
recognized  national  standing  selected  by the  Company  that,  in such firm's
opinion,  a registration  at the time and on the terms requested would adversely
affect any public  offering of securities  of the Company by the Company  (other
than in connection  with benefit and similar plans) (a "Company  Offering") with
respect to which the Company has commenced  preparations  for a registration and
filed or intends to imminently  file a registration  statement  relating to such
registration prior to the receipt of a registration  request pursuant to Section
4(a)  hereof,  until the  earlier  of (i) 90 days after the  completion  of such
Company  Offering,  or (ii)  promptly  after  any  abandonment  of such  Company
Offering.

Section 5. Piggyback Registrations.

(a) Right to Piggyback.  Whenever the Company proposes to register (including on
behalf of a selling  stockholder) any of its securities under the Securities Act
(except for the registration of securities to be offered pursuant to an employee
benefit plan on Form S-8 or Form S-3,  pursuant to a  registration  made on Form
S-4 or any successor  forms then in effect) at any time other than pursuant to a
Demand  Registration  and the  registration  form to be used may be used for the
registration of the Registrable Securities (a "Piggyback Registration"), it will
so notify in writing all Investor  Group  Designees no later than the earlier to
occur of (i) the tenth (10th) day following  the Company's  receipt of notice of
exercise of other demand registration  rights, or (ii) thirty (30) days prior to
the  anticipated  filing date.  Subject to the  provisions of Section 5(c),  the
Company will use its commercially reasonable efforts to include in the Piggyback
Registration  all  Registrable  Securities,  on a pro rata basis  based upon the
total  number of  Registrable  Securities  with respect to which the Company has
received  written  requests  for  inclusion  within  fifteen (15) days after the
Investor Group  Designees'  receipt of the Company's  notice.  A registration of
Registrable  Securities  pursuant  to this  Section 5 shall not be  counted as a
Demand Registration under Section 4.

(b) Piggyback Expenses.  The Company shall pay to the holders of the Registrable
Securities  included in a Piggyback  Registration all  Registration  Expenses of
those holders (except to the extent  prohibited by applicable  state  securities
laws).

(c) Priority on Piggyback Registrations. If the managing underwriter advises the
Company  in  writing  that the  total  number or  dollar  amount  of  securities
requested to be included in the registration exceeds the number or dollar amount
of securities  that can be sold,  the Company will include the securities in the
registration in the following order of priority,  subject to the priority rights
of the holders of securities  requesting  registration  pursuant to the Existing
Registration  Rights  Agreements:  (i) first,  all securities the Company or the
holder for whom the Company is effecting the  registration,  as the case may be,
proposes  to sell;  (ii)  second,  up to the full  number  or  dollar  amount of
Registrable  Securities requested to be included in the registration  (allocated
pro rata among the holders of Registrable Securities, on the basis of the number
of  Registrable  Securities  requested to be included,  as the case may be); and
(iii) third,  any other  securities  (provided they are of the same class as the
securities  sold by the Company)  requested to be included,  allocated among the
holders of such securities in such  proportions as the Company and those holders
may agree. In the event that the managing  underwriter  advises the Company that
an underwriters'  over-allotment option is necessary or advisable, the preceding
priority shall apply.

(d) Selection of Underwriters.  If any Piggyback Registration is an underwritten
offering,  the Company will select the investment  banker(s) and manager(s) that
will  administer  the  offering.  The  Company  and the  holders of  Registrable
Securities  whose  shares are being  registered  shall  enter  into a  customary
underwriting agreement with such investment banker(s) and manager(s).

Section 6. Holdback Agreements.

(a)  Restrictions  on Public Sale by Securities  Holders.  Each  Stockholder (i)
agrees not to make any public sale or distribution  of equity  securities of the
Company (except as part of the underwritten  registration effected pursuant to a
Demand Registration or a Piggyback  Registration),  including a sale pursuant to
Rule  144,during  the  period  beginning  seven (7) days  prior to and ending on
ninety  (90)  days  following  the  effective  date of any  underwritten  Demand
Registration  or  any  underwritten   Piggyback  Registration  as  any  managing
underwriter(s) of such underwriting may reasonably request,  and (ii) agrees not
to make any public sale or distribution of equity securities of the Company,  in
each  case  including  a sale  pursuant  to Rule  144,  during  (A) the  periods
described in Section 5.3(b)(ii) of the Bridge Registration Rights Agreement, (B)
the  periods  described  in  Section  5.3(b)(ii)  of the  Amended  and  Restated
Registration Rights Agreement,  and (C) the period described in Section 3(b)(ii)
of the Motorola Registration Rights Agreement, provided that such agreements are
in full force and effect.

(b)  Restrictions  on Public Sale by the Company and Others.  The Company agrees
not to make any public sale or  distribution  of its equity  securities,  or any
securities  convertible  into or  exchangeable  or  exercisable  for its  equity
securities (except as part of the underwritten registration effected pursuant to
a Demand  Registration or a Piggyback  Registration or pursuant to registrations
on Forms S-8 or S-4 or any  successor  form or on Form S-3 with  respect  to any
employee  benefit plans of the Company),  during such customary  period prior to
and following the effective date of any underwritten  Demand Registration or any
underwritten  Piggyback  Registration  as any  managing  underwriter(s)  of such
underwriting may reasonably  request.  The Company also agrees to use reasonable
efforts to cause each holder of at least 10% (on a  fully-diluted  basis) of its
equity  securities  (other  than  Registrable   Securities)  or  any  securities
convertible into or exchangeable or exercisable for its equity securities (other
than Registrable Securities), purchased from the Company at any time on or after
the date of this  Agreement  (other than in a registered  public  offering),  to
agree not to make any public sale or distribution of those securities, including
a sale pursuant to Rule 144 (except as part of the underwritten registration, if
permitted),  during the seven (7) days  prior to and the ninety  (90) days after
the effective date of the registration unless the managing underwriter(s) agrees
otherwise.

Section 7. Registration Procedures.

(a) Obligations of the Company.  Whenever the holders of Registrable  Securities
request  or are  entitled  to the  registration  of any  Registrable  Securities
pursuant to this Agreement,  the Company shall use its  commercially  reasonable
efforts to  register  and to permit the sale of the  Registrable  Securities  in
accordance  with  the  intended  method  of  disposition.   To  carry  out  this
obligation, the Company shall as expeditiously as practicable:

(1)      prepare   and  file   with  the  SEC  a   registration   statement   or
         post-effective  amendment to a registration statement, as necessary, on
         the appropriate form and use commercially  reasonable  efforts to cause
         the registration statement to become effective.  At least ten (10) days
         before filing a registration  statement or prospectus or at least three
         (3) business days before filing any amendments or supplements  thereto,
         the Company will furnish to the counsel of the holders of a majority of
         the Registrable  Securities  being  registered  copies of all documents
         proposed  to be filed for that  counsel's  review and  approval,  which
         approval shall not be unreasonably withheld or delayed;

(2)      immediately  notify  each  Investor  Group  Designee  of any stop order
         threatened  or  issued  by the  SEC and  take  all  actions  reasonably
         required  to prevent the entry of a stop order or if entered to have it
         rescinded or otherwise removed;

(3)      prepare and file with the SEC such  amendments  and  supplements to the
         registration  statement and the corresponding  prospectus  necessary to
         keep the registration  statement  effective for such period required by
         Section 3(b) or Section 4(g) or such shorter  period as may be required
         to  sell  all  Registrable   Securities  covered  by  the  registration
         statement;  and comply with the  provisions of the  Securities Act with
         respect  to  the   disposition  of  all   securities   covered  by  the
         registration  statement  during  each  period  in  accordance  with the
         sellers'   intended   methods  of  disposition  as  set  forth  in  the
         registration statement;

(4)      furnish to each Investor Group  Designee a sufficient  number of copies
         of the registration  statement,  each amendment and supplement  thereto
         (in each case including all  exhibits),  the  corresponding  prospectus
         (including each preliminary prospectus), and such other documents as an
         Investor  Group  Designee  may  reasonably  request to  facilitate  the
         disposition of the Registrable Securities held by the Investors in such
         Investor Group;

(5)      use its  commercially  reasonable  efforts to  register  or qualify the
         Registrable   Securities   under   securities   or  blue  sky  laws  of
         jurisdictions  in the United  States of America as any  Investor  Group
         Designee  requests and do any and all other  reasonable acts and things
         that  may  be  necessary  or  advisable  to  enable  the  Investors  to
         consummate the  disposition of the  Registrable  Securities held by the
         Investors  in  such  Investor  Group  in such  jurisdiction;  provided,
         however,  that the  Company  shall not be  obligated  to  qualify  as a
         foreign  corporation to do business under the laws of any  jurisdiction
         in which it is not then  qualified  or to file any  general  consent to
         service of process;

(6)      notify each Investor Group  Designee,  at any time when a prospectus is
         required to be delivered  under the  Securities  Act, of any event as a
         result of which the prospectus or any document  incorporated therein by
         reference  contains an untrue  statement of a material fact or omits to
         state any material fact  necessary to make the  statements  therein not
         misleading in light of the  circumstances  under which such  statements
         were made,  and  promptly  prepare a  supplement  or  amendment  to the
         prospectus or any such document incorporated therein so that thereafter
         the prospectus will not contain an untrue  statement of a material fact
         or omit to state any material  fact  necessary  to make the  statements
         therein not misleading in light of the  circumstances  under which such
         statements were made;

(7)      cause  all  registered  Registrable  Securities  to be  listed  on each
         securities exchange,  if any, on which similar securities issued by the
         Company are then listed;

(8)      provide  an  institutional  transfer  agent and  registrar  and a CUSIP
         number for all  Registrable  Securities on or before the effective date
         of the registration statement;

(9)      enter  into  such  customary  agreements   (including  an  underwriting
         agreement in customary  form) and take all other  actions in connection
         with  those   agreements  as  the  Investor   Group   Designee  or  the
         underwriters,  if any, reasonably request to expedite or facilitate the
         disposition   of  the   Registrable   Securities   including,   without
         limitation,  the participation of senior management in "road shows" and
         similar activities, provided that such activities do not interfere with
         the  duties of  senior  management  in a manner  that  would  likely be
         detrimental to the best interests of the Company;

(10)     make  available for  inspection  by any Investor  Group  Designee,  any
         underwriter   participating   in  any   disposition   pursuant  to  the
         registration statement, and any attorney, accountant, or other agent of
         any Investor Group Designee or  underwriter,  all reasonable  financial
         and other records, pertinent corporate documents, and properties of the
         Company,  and cause the Company's officers,  directors and employees to
         supply all  information  reasonably  requested  by any  Investor  Group
         Designee,   underwriter,   attorney,  accountant,  or  other  agent  in
         connection  with  the  registration   statement;   provided,   that  an
         appropriate and customary  confidentiality agreement is executed by any
         such Investor  Group  Designee,  underwriter,  attorney,  accountant or
         other agent;

(11)     in connection with any underwritten offering, obtain a "comfort" letter
         from the Company's independent public accountants in customary form and
         covering those matters  customarily covered by "comfort" letters as the
         Investor Group Designee or the managing underwriter reasonably requests
         (and,  if the  Company  is able  after  using  commercially  reasonable
         efforts,  the letter shall be  addressed to holders of the  Registrable
         Securities, the Company and the underwriters);

(12)     in connection with any underwritten  offering,  furnish, at the request
         of any Investor Group Designee or  underwriter(s)  of the offering,  an
         opinion of counsel  representing  the Company  for the  purposes of the
         registration,   in  the  form  and  substance   customarily   given  to
         underwriters  in  an   underwritten   public  offering  and  reasonably
         satisfactory  to counsel  representing  the Investor Group Designee and
         the  underwriter(s) of the offering,  addressed to the underwriters and
         to the holders of the Registrable Securities being registered;

(13)     use  its  best   efforts  to  comply  with  all  applicable  rules  and
         regulations of the SEC;

(14)     cooperate  with  each  Investor  Group  Designee  and each  underwriter
         participating  in the  disposition of such  Registrable  Securities and
         their respective  counsel in connection with any filings required to be
         made with the NASD; and

(15)     take all other steps reasonably necessary to effect the registration of
         the Registrable Securities contemplated hereby.

(b) Seller  Information.  In the event of any registration by the Company,  from
time to time, the Company may require each Investor Group Designee to furnish to
the Company information regarding each seller of Registrable  Securities subject
to the  registration  and the  distribution  of the  securities  subject  to the
registration,   and  such  Investor   Group  Designee  shall  furnish  all  such
information requested by the Company.

(c) Notice to  Discontinue.  Each  holder of  Registrable  Securities  agrees by
acquisition of such securities that, upon receipt of any notice from the Company
to the Investor  Group  Designees of any event of the kind  described in Section
7(a)(6), the holder will discontinue disposition of Registrable Securities until
the Investor  Group  Designee  receives  copies of the  supplemented  or amended
prospectus  contemplated  by  Section  7(a)(6).  In  addition,  if  the  Company
requests,  each Investor Group Designee will cause each holder to deliver to the
Company (at the Company's expense) all copies,  other than permanent file copies
then in the holder's  possession,  of the  prospectus  covering the  Registrable
Securities  current at the time of receipt of the notice.  If the Company  gives
any such notice,  the time period mentioned in Section 7(a)(3) shall be extended
by the number of days elapsing between the date of notice and the date that each
seller  receives  the  copies  of  the   supplemented   or  amended   prospectus
contemplated in Section 7(a)(6).

(d) Notice by Holders.  Whenever  the  holders of  Registrable  Securities  have
requested  that  any  Registrable  Securities  be  registered  pursuant  to this
Agreement, those holders shall notify the Company, at any time when a prospectus
relating  thereto is required to be delivered  under the Securities  Act, of the
happening of any event, which as to any holder of Registrable  Securities is (i)
to his or its  respective  knowledge,  (ii) solely within his or its  respective
knowledge  and  (iii)  solely  as to  matters  concerning  that  holder  of  the
Registrable  Securities,  as a result of which the  prospectus  included  in the
registration  statement contains an untrue statement of a material fact or omits
to state any material fact necessary to make the statements therein, in light of
the circumstances under which they were made, not misleading.

Section 8. Registration Expenses.

(a) Generally.  All Registration  Expenses incident to the Company's performance
of or  compliance  with  this  Agreement  shall  be  paid  as  provided  in this
Agreement.  The term "Registration Expenses" includes,  without limitation,  all
registration  filing fees,  reasonable  professional  fees and other  reasonable
expenses of the Company's  compliance with federal,  state and other  securities
laws  (including  fees and  disbursements  of counsel  for the  underwriters  in
connection with state or other securities law qualifications and registrations),
printing expenses,  messenger,  telephone and delivery expenses; reasonable fees
and  disbursements of counsel for the Company;  reasonable fees and disbursement
of all independent  certified public accountants  (including the expenses of any
audit or  "comfort"  letters  required  by or  incident  to  performance  of the
obligations   contemplated  by  this  Agreement);   fees  and  expenses  of  the
underwriters  (excluding  discounts and  commissions);  fees and expenses of any
special  experts  retained  by the  Company  at  the  request  of  the  managing
underwriters in connection with the registration;  and applicable stock exchange
and NASD registration and filing fees. The term "Registration Expenses" does not
include the Company's  internal expenses  (including,  without  limitation,  all
salaries  and  expenses  of its  officers  and  employees  performing  legal  or
accounting  duties),  the expense of any annual  audit and the fees and expenses
incurred in  connection  with the listing of the  securities to be registered on
each securities  exchange on which similar  securities issued by the Company are
then  listed,  all of which  shall be paid by the  Company,  nor does it include
underwriting fees, discounts or selling commissions,  brokerage fees or transfer
taxes, or the fees and  disbursements  or counsel for the sellers,  all of which
shall be paid by the sellers of Registrable Securities.

(b)  Other  Expenses.  To  the  extent  the  Company  is  not  required  to  pay
Registration  Expenses,  each holder of securities  included in any registration
will pay those  Registration  Expenses  allocable to the holder's  securities so
included,  and any  Registration  Expenses  not  allocable  will be borne by all
sellers in proportion to the number of securities each  registers.  Furthermore,
the Stockholders hereby agree amongst themselves that any Registration  Expenses
or other cost and expenses in connection with an S-4  Registration or the Demand
Registration  not  required  to be paid by the  Company  that  are  borne by the
holders of the Registrable  Securities in accordance with the previous sentence,
shall be shared pro rata among the Investor  Groups that are  exercising or have
previously  exercised  their  right to a Parent  Conversion,  including,  to the
extent  necessary,  subsequent  reimbursement  by Investors who have  previously
exercised a Parent  Conversion  and requested an S-4  Registration  to Investors
then exercising a Parent Conversion and requesting an S-4 Registration.

Section 9. Indemnification.

(a)  Indemnification by Company. In the event of any registration of Registrable
Securities  under the  Securities  Act pursuant to this  Agreement,  to the full
extent  permitted  by law,  the  Company  agrees  to  indemnify  each  holder of
Registrable Securities, its officers, directors,  trustees, partners, employees,
advisors and agents, and each Person who controls the holder (within the meaning
of the Securities Act and the Exchange Act) against all losses, claims, damages,
liabilities and expenses caused by any untrue or allegedly  untrue  statement of
material  fact  contained  in  any  registration   statement  under  which  such
Registrable  Securities were registered under the Securities Act, any prospectus
or preliminary  prospectus contained therein or any omission or alleged omission
to state a material fact required to be stated  therein or necessary to make the
statements therein not misleading in light of the circumstances under which such
statements  were  made,  except to the extent  the  untrue or  allegedly  untrue
statement or omission or alleged  omission  resulted from  information  that the
holder  furnished  in writing  to the  Company  expressly  for use  therein.  In
connection  with a firm or best  efforts  underwritten  offering,  to the extent
customarily required by the managing underwriter, the Company will indemnify the
underwriters,  their  officers  and  directors  and each Person who controls the
underwriters (within the meaning of the Securities Act and the Exchange Act), to
the extent customary in such agreements.

(b)   Indemnification   by  Holders  of  Securities.   In  connection  with  any
registration statement, each participating holder of Registrable Securities will
furnish to the Company in writing such information and affidavits as the Company
reasonably  requests for use in connection  with any  registration  statement or
prospectus and each holder agrees to indemnify,  to the extent permitted by law,
the Company, its directors,  officers, trustees, partners,  employees,  advisors
and agents,  and each Person who controls the Company (within the meaning of the
Securities  Act and the  Exchange  Act)  against  any losses,  claims,  damages,
liabilities and expenses resulting from any untrue or allegedly untrue statement
of a material fact or any omission or alleged  omission to state a material fact
required  to be  stated  in the  registration  statement  or  prospectus  or any
amendment thereof or supplement thereto necessary to make the statements therein
not misleading in light of the  circumstances  under which such  statements were
made,  but only to the extent that the untrue or allegedly  untrue  statement or
omission or alleged  omission is contained in or omitted from any information or
affidavit  the holder  furnished  in writing to the  Company  expressly  for use
therein and only in an amount not  exceeding  the net  proceeds  received by the
holder with respect to securities sold pursuant to such registration  statement.
In connection with a firm or best efforts underwritten  offering,  to the extent
customarily required by the managing  underwriter,  each participating holder of
Registrable  Securities  will  indemnify the  underwriters,  their  officers and
directors and each Person who controls the  underwriters  (within the meaning of
the  Securities  Act and the  Exchange  Act),  to the extent  customary  in such
agreements.

(c) Indemnification  Proceedings.  Any Person entitled to indemnification  under
this  Agreement  will (i) give prompt  notice to the  indemnifying  party of any
claim with  respect  to which it seeks  indemnification  and (ii)  unless in the
indemnified party's reasonable judgment a conflict of interest may exist between
the indemnified and indemnifying  parties with respect to the claim,  permit the
indemnifying  party to assume the defense of the claim with  counsel  reasonably
satisfactory to the indemnified party. If the indemnifying party does not assume
the defense,  the indemnifying  party will not be liable for any settlement made
without its consent  (but that  consent may not be  unreasonably  withheld).  No
indemnifying  party will consent to entry of any judgment or will enter into any
settlement that does not include as an unconditional term thereof the claimant's
or plaintiff's  release of the indemnified  party from all liability  concerning
the claim or litigation.  An indemnifying party who is not entitled to or elects
not to assume the defense of a claim will not be under an  obligation to pay the
fees and  expenses of more than one counsel for all parties  indemnified  by the
indemnifying party with respect to the claim,  unless in the reasonable judgment
of  any  indemnified  party  a  conflict  of  interest  may  exist  between  the
indemnified  party and any other indemnified party with respect to the claim, in
which  event  the  indemnifying  party  shall be  obligated  to pay the fees and
expenses of no more than one additional counsel for the indemnified parties.

(d) Contribution.  If the indemnification provided for in Section 9(a) or (b) is
unavailable to an indemnified party in respect of any losses,  claims,  damages,
liabilities  or  expenses  referred  to therein,  then each  indemnifying  party
thereunder  shall  contribute to the amount paid or payable by such  indemnified
party as a result of such losses,  claims,  damages,  liabilities or expenses in
such  proportion as is  appropriate to reflect the relative fault of the Company
and the participating  holders of Registrable  Securities in connection with the
statements  or  omissions  that  resulted  in  such  losses,  claims,   damages,
liabilities or expenses, as well as any other relevant equitable considerations.
The relative fault of the Company and the  participating  holders of Registrable
Securities shall be determined by reference to, among other things,  whether the
untrue or alleged untrue statement of a material fact or the omission or alleged
omission to state a material fact relates to information supplied by the Company
or by the  participating  holders of  Registrable  Securities  and the  parties'
relative intent and knowledge.

         The parties  hereto  agree that it would not be just and  equitable  if
contribution  pursuant this Section 9(d) were  determined by pro rata allocation
or by any other method of allocation that does not take account of the equitable
considerations   referred   to   in   the   immediately   preceding   paragraph.
Notwithstanding  anything  herein to the contrary,  no  participating  holder of
Registrable  Securities  shall be required to contribute any amount in excess of
the amount by which the net proceeds of the offering (before deducting expenses,
if any) received by such participating  holder exceeds the amount of any damages
that such  participating  holder has otherwise been required to pay by reason of
such untrue or alleged  untrue  statement  or omission or alleged  omission.  No
Person  guilty of  fraudulent  misrepresentation  (within the meaning of Section
11(f) of the Securities Act) shall be entitled to  contribution  from any Person
who was not guilty of such fraudulent misrepresentation.

Section  10 . Rule 144.  The  Company  covenants  that it will file the  reports
required to be filed by it under the Securities Act and the Exchange Act and the
rules  and  regulations  adopted  by the SEC  thereunder,  and it will take such
further action as any Investor Group Designee reasonably may request, all to the
extent  required  from  time to time,  to enable  such  holders  of  Registrable
Securities to sell such Registrable  Securities  without  registration under the
Securities Act within the limitation of the exemptions  provided by (i) Rule 144
under the  Securities  Act, or (ii) any  similar  rule or  regulation  hereafter
adopted by the SEC.  Upon the request of any holder of  Registrable  Securities,
the Company will deliver to such holder a written statement as to whether it has
complied with Rule 144's or any successor rule's requirements.  The Company also
covenants  that in such event it will provide all such  information  and it will
take such further action as any holder of Registrable  Securities reasonably may
request  to  enable  such  holder  to  sell   Registrable   Securities   without
registration  under the  Securities  Act within the limitation of Rule 144 under
the Securities Act or any successor rule requirements.

Section  11  .  Participation  in  Underwritten  Registration.   No  Person  may
participate  in any  underwritten  registration  without  (a)  agreeing  to sell
securities on the basis provided in  underwriting  arrangements  approved by the
Persons  entitled  hereunder  to approve such  arrangements  (the holders of the
Registrable Securities in a Demand Registration pursuant to Section 4(d) and the
Company  in  a  Piggyback  Registration  pursuant  to  Section  5(d)),  and  (b)
completing and executing all  questionnaires,  powers of attorney,  indemnities,
underwriting  agreements  and  other  documents  required  by  the  underwriting
arrangements.

Section 12. Miscellaneous.

(a)  Recapitalizations,  Exchanges,  etc. The provisions of this Agreement shall
apply to the full  extent  set forth  herein  with  respect to (i) the shares of
Common Stock held by the Stockholders and acquired  pursuant to the transactions
contemplated by the Investment  Agreement (or their  transferees),  (ii) any and
all shares of voting  common  stock of the Company into which the shares of such
Common Stock are converted,  exchanged or substituted in any recapitalization or
other  capital  reorganization  by the  Company  and  (iii)  any and all  equity
securities of the Company or any successor or assign of the Company  (whether by
merger,  consolidation,  sale of  assets  or  otherwise)  which may be issued in
respect of, in conversion of, in exchange for or in substitution of, such shares
of Common Stock and shall be  appropriately  adjusted  for any stock  dividends,
splits, reverse splits,  combinations,  recapitalizations and the like occurring
after the date hereof. The Company shall use its commercially reasonable efforts
to cause any successor or assign (whether by sale, merger or otherwise) to enter
into a new  registration  rights  agreement  with  the  holders  of  Registrable
Securities on terms  substantially  the same as this Agreement as a condition of
any such transaction.

(b)  Amendment.  This  Agreement  may be amended or  modified  only by a written
agreement executed by the Company and the Stockholders.

(c)  Attorneys'  Fees. In any legal action or proceeding  brought to enforce any
provision of this Agreement,  the prevailing  party shall be entitled to recover
all reasonable expenses, charges, court costs and attorneys' fees in addition to
any other available remedy at law or in equity.

(d)  Benefit of Parties;  Assignment.  All of the terms and  provisions  of this
Agreement  shall be binding on and inure to the benefit of the parties and their
respective successors and assigns, including,  without limitation, any Person to
whom the Investors may transfer any of its Registrable Securities (or any rights
to acquire  Registrable  Securities);  provided  any such  successor or assignee
shall  agree in  writing  to  become  bound by the  terms of this  Agreement  by
executing and delivering a Joinder Agreement.

(e) Captions. The captions of the sections and subsections of this Agreement are
solely for convenient reference and shall not be deemed to affect the meaning or
interpretation of any provision of this Agreement.

(f)  Cooperation.  The parties agree that after execution of this Agreement they
will from time to time,  upon the request of any other party and without further
consideration,  execute,  acknowledge  and  deliver in proper  form any  further
instruments and take such other action as any other party may reasonably require
to carry out effectively the intent of this Agreement.

(g)  Counterparts;   Facsimile   Execution.   This  Agreement  may  be  executed
simultaneously  in two or more  counterparts,  each of which  shall be deemed an
original, but all of which together shall constitute one and the same agreement.
Facsimile  execution and delivery of this  Agreement  shall be legal,  valid and
binding execution and delivery for all purposes.

(h) Entire Agreement.  This Agreement  contains the entire  understanding of the
parties with respect to the subject  matter of this Agreement and supersedes all
prior  agreements and  understandings  between the parties with respect thereto.
There are no promises,  covenants or undertakings other than those expressly set
forth or provided for in this Agreement.

(i) Governing Law. The internal law of the  Commonwealth of Virginia will govern
the  interpretation,  construction,  and  enforcement  of this Agreement and all
transactions and agreements  contemplated  hereby,  notwithstanding  any state's
choice of law rules to the contrary.

(j) No Inconsistent Agreements.  Except with respect to the rights granted under
the Existing  Registration Rights Agreements and the Warrant Registration Rights
Agreement,  the Company  represents  and warrants that it has not granted to any
Person the right to request or require the Company to  register  any  securities
issued by the Company other than the rights  contained  herein.  Except with the
prior written consent of the holders of Registrable Securities, the Company will
not enter into any agreement with respect to its securities  that shall grant to
any Person  registration  rights that in any way  conflict  with or are prior in
right to the rights provided under this Agreement. The parties to this Agreement
acknowledge  and agree that it is their intent that this Agreement be consistent
with the  terms of the  Existing  Registration  Rights  Agreements  and that the
Company  have no  obligation  under  this  Agreement  which  conflicts  with its
obligations  under the Existing  Registration  Rights  Agreements.  To that end,
notwithstanding  anything to the contrary  contained in this  Agreement,  to the
extent that any of the  provisions  of this  Agreement  conflict with any of the
provisions of the Existing Registration Rights Agreements, the Company shall not
be obligated to comply with its obligations under the conflicting  provisions of
this  Agreement  until it can do so  without  violating  the  provisions  of the
Existing Registration Rights Agreements.

(k) Notices.  All notices,  requests,  demands, or other communications that are
required  or may be given  pursuant to the terms of this  Agreement  shall be in
writing and delivery shall be deemed sufficient in all respects and to have been
duly given on the date of service if delivered  personally  to the party to whom
notice is to be given,  or upon  receipt if mailed by first class  mail,  return
receipt requested,  postage prepaid,  and properly addressed to the addresses of
the parties set forth on the signature pages hereto or in the Joinder  Agreement
or to such other address(es) as the respective parties hereto shall from time to
time designate to the other(s) in writing.

(l) Specific  Performance.  Each of the parties agrees that damages for a breach
of or default under this  Agreement  would be inadequate and that in addition to
all other  remedies  available  at law or in equity  that the  parties and their
successors  and assigns shall be entitled to specific  performance or injunctive
relief,  or both,  in the  event  of a breach  or a  threatened  breach  of this
Agreement.

(m) Validity of Provisions.  Should any part of this Agreement for any reason be
declared by any court of competent  jurisdiction  to be invalid,  that  decision
shall not affect the validity of the remaining portion,  which shall continue in
full force and effect as if this  Agreement  had been  executed with the invalid
portion  eliminated,  it being the  intent of the  parties  that they would have
executed the remaining  portion of the Agreement  without  including any part or
portion that may for any reason be declared invalid.

                  [remainder of page intentionally left blank]

<PAGE>

                            SEPARATE SIGNATURE PAGE
                         REGISTRATION RIGHTS AGREEMENT

         IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as
of the date first above written.

                                     MOTIENT CORPORATION

                                     By:  /s/Gary M. Parsons
                                          Name:  Gary M. Parsons
                                          Title: Chairman

                                          Address for Notices:

                                          Motient Corporation
                                          10802 Parkridge Boulevard
                                          Reston, Virginia  20191-5416
                                          Fax:  (703) 758-6134
                                          Attention:   Randy S. Segal, Esq.
                                                       Senior Vice President and
                                                       General Counsel

<PAGE>

                            SEPARATE SIGNATURE PAGE
                         REGISTRATION RIGHTS AGREEMENT

     IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement as
of the date first above written.

                                      INVESTOR GROUP 1:

                                      TELCOM SATELLITE VENTURES INC.

                                      By:  /s/Rahul Prakash
                                           Name:  Rahul Prakash
                                           Title: President

                                      Address for Notices to the Investors in
                                      Investor Group 1:

                                      Telecom Satellite Ventures Inc.
                                      c/o Telcom Ventures, L.L.C.
                                      211 North Union Street
                                      Suite 300
                                      Alexandria, Virginia 22314
                                      Fax:  (703)706-3801
                                      Attention:  Hal Perkins, Esq.
                                                  General Counsel

<PAGE>

                            SEPARATE SIGNATURE PAGE
                         REGISTRATION RIGHTS AGREEMENT

     IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement as
of the date first above written.

                                      INVESTOR GROUP 2:

                                      COLUMBIA SPACE (QP), INC.

                                      By:  /s/James B. Fleming
                                           Name:  James B. Fleming
                                           Title: President

                                      COLUMBIA SPACE (A1), INC.

                                      By:  /s/James B. Fleming
                                           Name:  James B. Fleming
                                           Title: President

                                      COLUMBIA SPACE PARTNERS, INC.

                                      By:  /s/James B. Fleming
                                           Name:  James B. Fleming
                                           Title: President

<PAGE>

                            SEPARATE SIGNATURE PAGE
                         REGISTRATION RIGHTS AGREEMENT

                                      Address for Notices to the
                                      Investors in Investor Group 2:

                                      Columbia Space (QP), Inc.
                                      211 North Union Street
                                      Suite 300
                                      Alexandria, Virginia 22314
                                      Attention:  James Fleming
                                      Tel:  (703)519-3000
                                      Fax:  (703)519-3028

                                      with a copy to:
                                      Edwards & Angell, LLP
                                      101 Federal Street
                                      Boston, MA 02100
                                      Attention:  Stephen Meredith, Esq.
                                      Tel. (617)951-2233
                                      Fax: (888)325-9120

<PAGE>
                            SEPARATE SIGNATURE PAGE
                         REGISTRATION RIGHTS AGREEMENT

     IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement as
of the date first above written.

                                      INVESTOR GROUP 3:

                                      SPECTRUM SPACE EQUITY
                                      INVESTORS IV, INC.

                                      By:  /s/Kevin J. Maroni
                                           Name:  Kevin J. Maroni
                                           Title: Chairman and CEO

                                      SPECTRUM SPACE IV PARALLELL, INC.

                                      By:  /s/Kevin J. Maroni
                                           Name:  Kevin J. Maroni
                                           Title: Chairman and CEO

                                      SPECTRUM SPACE IV MANAGERS', INC.

                                      By:  /s/Kevin J. Maroni
                                           Name:  Kevin J. Maroni
                                           Title: Chairman and CEO
<PAGE>

                            SEPARATE SIGNATURE PAGE
                         REGISTRATION RIGHTS AGREEMENT

                                      Address for Notices to the Investors in
                                      Investor Group 3:

                                      Spectrum Space Equity Investors IV, Inc.
                                      One International Place
                                      29th Floor
                                      Boston, MA 82110
                                      Attention:  Kevin Maroni
                                      Tel:  (617)464-4600
                                      Fax:  (617)464-4601

                                      with a copy to:
                                      Edwards & Angell, LLP
                                      101 Federal Street
                                      Boston, MA 02100
                                      Attention:  Stephen Meredith, Esq.
                                      Tel:  (617)951-2233
                                      Fax:  (888)325-9120

<PAGE>

                                                                      EXHIBIT A

                            FORM OF JOINDER AGREEMENT

                                JOINDER AGREEMENT

         This Joinder  Agreement dated as of  ___________,  200_ is executed and
delivered  pursuant to Section 11(d) of the Registration  Rights Agreement dated
as of June ___, 2000 (the "Registration  Rights Agreement") by and among Motient
Corporation   (the   "Company")   and  the   stockholders   party  thereto  (the
"Stockholders").  Capitalized  terms used by not defined  herein  shall have the
respective meanings assigned to such terms in the Registration Rights Agreement.

         The undersigned,  _______________  (the "New Stockholder") has acquired
shares of Common Stock of the Company and therefore desires to become a party to
the  Registration  Rights  Agreement on the terms set forth in the  Registration
Rights Agreement. Accordingly, the New Stockholder hereby agrees as follows:

         1.       By its signature below,  the New Stockholder  shall be a party
to the  Registration  Rights  Agreement  fully and completely the same as if its
signature were affixed to the Registration Rights Agreement.

         2.       The  New Stockholder is a Stockholder  under the  Registration
Rights Agreement with all the rights of obligations of a Stockholder thereunder.

         3.       This  Joinder  Agreement shall be governed by and construed in
accordance with the laws of the Commonwealth of Virginia.

<PAGE>

         IN WITNESS WHEREOF,  the undersigned has caused this Joinder  Agreement
to be executed and delivered as of the date first above written.

                                     [NEW STOCKHOLDER]

                                     By:_______________________________
                                     Name:
                                     Title:

                                                     Address for Notices:
                                                     =================
                                     Fax:

                                     Attention:

ACCEPTED:

MOTIENT CORPORATION

By: _______________________________
    Name:
    Title:

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}]]