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                                                                     EXHIBIT 4.7



                              IRIDIUM OPERATING LLC
                           IRIDIUM CAPITAL CORPORATION


                     _____% Senior Notes due 2005, Series D

                       Guaranteed by Iridium Roaming LLC,
                               Iridium IP LLC and
                         Iridium Facilities Corporation


                             SERIES D NOTE INDENTURE


                            Dated as of May __, 1998


                              State Street Bank and
                                 Trust Company,
                                     Trustee
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                                TABLE OF CONTENTS

                                                                            Page



ARTICLE I  Definitions and Incorporation by Reference........................1

      SECTION 1.01.  Definitions.............................................1
      SECTION 1.02.  Other Definitions......................................16
      SECTION 1.03.  Incorporation by Reference of Trust Indenture Act......16
      SECTION 1.04.  Rules of Construction..................................16


ARTICLE II  The Notes.......................................................17

      SECTION 2.01.  Form and Dating........................................17
      SECTION 2.02.  Execution and Authentication...........................17
      SECTION 2.03.  Registrar and Paying Agent.............................18
      SECTION 2.04.  Paying Agent To Hold Money in Trust....................18
      SECTION 2.05.  Holder Lists...........................................19
      SECTION 2.06.  Transfer and Exchange..................................19
      SECTION 2.07.  Replacement Notes......................................19
      SECTION 2.08.  Outstanding Notes......................................20
      SECTION 2.09.  Temporary Notes........................................20
      SECTION 2.10.  Cancellation...........................................20
      SECTION 2.11.  Defaulted Interest.....................................20
      SECTION 2.12.  CUSIP Numbers..........................................20
      SECTION 2.13.  Book-Entry Provisions for Global Notes.................21


ARTICLE III  Redemption.....................................................22

      SECTION 3.01.  Notices to Trustee.....................................22
      SECTION 3.02.  Selection of Securities to be Redeemed.................22
      SECTION 3.03.  Notice of Redemption...................................22
      SECTION 3.04.  Effect of Notice of Redemption.........................23
      SECTION 3.05.  Deposit of Redemption Price............................23
      SECTION 3.06.  Notes Redeemed in Part.................................23
      SECTION 3.07.  Optional Redemption....................................23


ARTICLE IV  Covenants.......................................................23

      SECTION 4.01.  Payment of Notes.......................................23
      SECTION 4.02.  SEC Reports............................................24
      SECTION 4.03.  Limitation on Indebtedness.............................24
      SECTION 4.04.  Limitation on Restricted Payments......................25
      SECTION 4.05.  Limitation on Restrictions on Distributions from
                     Restricted Subsidiaries................................27
      SECTION 4.06.  Limitation on Sales of Assets and Subsidiary Stock.....28
      SECTION 4.07.  Limitation on Transactions with Affiliates.............29
      SECTION 4.08.  Change of Control......................................30
      SECTION 4.09.  Compliance Certificate.................................30
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      SECTION 4.10.  [Reserved].............................................30
      SECTION 4.11.  Limitation on the Sale or Issuance of Capital
                     Stock of Restricted Subsidiaries.......................31
      SECTION 4.12.  Limitation on Liens....................................31
      SECTION 4.13.  Limitation on Lines of Business........................31
      SECTION 4.14.  Limitation on Business Activities of Capital...........31
      SECTION 4.15.  Future Guarantor Subsidiaries..........................31
      SECTION 4.16.  Maintenance of Insurance...............................31


ARTICLE V  Successor Companies..............................................32

      SECTION 5.01.  When Issuers May Merge or Transfer Assets..............32


ARTICLE VI  Defaults and Remedies...........................................33

      SECTION 6.01.  Events of Default......................................33
      SECTION 6.02.  Acceleration...........................................35
      SECTION 6.03.  Other Remedies.........................................35
      SECTION 6.04.  Waiver of Past Defaults................................35
      SECTION 6.05.  Control by Majority....................................35
      SECTION 6.06.  Limitation on Suits....................................35
      SECTION 6.07.  Rights of Holders to Receive Payment...................36
      SECTION 6.08.  Collection Suit by Trustee.............................36
      SECTION 6.09.  Trustee May File Proofs of Claim.......................36
      SECTION 6.10.  Priorities.............................................36
      SECTION 6.11.  Undertaking for Costs..................................36
      SECTION 6.12.  Waiver of Stay or Extension Laws.......................37
      SECTION 6.13.  Restoration of Rights and Remedies.....................37


ARTICLE VII  Trustee........................................................37

      SECTION 7.01.  Duties of Trustee......................................37
      SECTION 7.02.  Rights of Trustee......................................38
      SECTION 7.03.  Individual Rights of Trustee...........................38
      SECTION 7.04.  Trustee's Disclaimer...................................38
      SECTION 7.05.  Notice of Defaults.....................................38
      SECTION 7.06.  Reports by Trustee to Holders..........................39
      SECTION 7.07.  Compensation and Indemnity.............................39
      SECTION 7.08.  Replacement of Trustee.................................39
      SECTION 7.09.  Successor Trustee by Merger............................40
      SECTION 7.10.  Eligibility; Disqualification..........................40
      SECTION 7.11.  Preferential Collection of Claims Against Issuers......40


ARTICLE VIII  Discharge of Indenture; Defeasance............................40

      SECTION 8.01.  Discharge of Liability on Notes; Defeasance............40
      SECTION 8.02.  Conditions to Defeasance...............................41
      SECTION 8.03.  Application of Trust Money.............................42
      SECTION 8.04.  Repayment to Note Issuers..............................42
      SECTION 8.05.  Indemnity for Government Securities....................42
      SECTION 8.06.  Reinstatement..........................................42
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ARTICLE IX  Amendments......................................................43

      SECTION 9.01.  Without Consent of Holders.............................43
      SECTION 9.02.  With Consent of Holders................................43
      SECTION 9.03.  Compliance with Trust Indenture Act....................44
      SECTION 9.04.  Revocation and Effect of Consents and Waivers..........44
      SECTION 9.05.  Notation on or Exchange of Notes.......................44
      SECTION 9.06.  Trustee To Sign Amendments.............................44


ARTICLE X  Subsidiary Guarantees............................................44

      SECTION 10.01.  Subsidiary Guarantees.................................44
      SECTION 10.02.  Limitation on Liability...............................46
      SECTION 10.03.  Successors and Assigns................................46
      SECTION 10.04.  No Waiver.............................................46
      SECTION 10.05.  Modification..........................................46
      SECTION 10.06.  Initial Guarantors; Execution of Supplemental
                      Indenture for Future Guarantor Subsidiaries...........46


ARTICLE XI  Miscellaneous...................................................47

      SECTION 11.01.  Trust Indenture Act Controls..........................47
      SECTION 11.02.  Notices...............................................47
      SECTION 11.03.  Communication by Holders with Other Holders...........47
      SECTION 11.04.  Certificate and Opinion as to Conditions
                      Precedent.............................................47
      SECTION 11.05.  Statements Required in Certificate or Opinion.........48
      SECTION 11.06.  When Notes Disregarded................................48
      SECTION 11.07.  Rules by Trustee Paying Agent and Registrar...........48
      SECTION 11.08.  Legal Holidays........................................48
      SECTION 11.09.  Governing Law.........................................48
      SECTION 11.10.  No Recourse Against Others............................48
      SECTION 11.11.  Successors............................................49
      SECTION 11.12.  Multiple Originals....................................49
      SECTION 11.13.  Table of Contents; Headings...........................49

Exhibit A  -  Form of Note
Exhibit B  -  Form of Supplemental Indenture

Schedule I - Other Existing Affiliate Agreements
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                              CROSS-REFERENCE TABLE

  TIA                                                            Indenture
Section                                                           Section

  310.(a)(1)......................................................7.10
      (a)(2)......................................................7.10
      (a)(3)......................................................N.A.
      (a)(4)......................................................N.A.
      (b).........................................................7.08; 7.10
      (c).........................................................N.A.
  311 (a).........................................................7.11
      (b).........................................................7.11
      (c).........................................................N.A.
  312 (a).........................................................2.05
      (b).........................................................11.03
      (c).........................................................11.03
  313 (a).........................................................7.06
      (b)(1)......................................................N.A.
      (b)(2)......................................................7.06
      (c).........................................................11.02
      (d).........................................................7.06
  314 (a).........................................................4.02; 4.09
      (b).........................................................N.A.
      (c)(1)......................................................11.04
      (c)(2)......................................................11.04
      (c)(3)......................................................N.A.
      (d).........................................................N.A.
      (e).........................................................11.05
      (f).........................................................4.09
  315 (a).........................................................7.01
      (b).........................................................7.05; 11.02
      (c).........................................................7.01
      (d).........................................................7.01
      (e).........................................................6.11
  316 (a)(last sentence)..........................................11.06
      (a)(1)(A)...................................................6.05
      (a)(1)(B)...................................................6.04
      (a)(2)......................................................N.A.
      (b).........................................................6.07
  317 (a)(1)......................................................6.08
      (a)(2)......................................................6.09
      (b).........................................................2.04
  318 (a).........................................................11.01

                           N.A. means Not Applicable.

- ------------------
Note: This Cross-Reference Table shall not, for any purpose, be deemed to be
      part of this Indenture.
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        INDENTURE dated as of May __, 1998, among IRIDIUM OPERATING LLC, a
Delaware limited liability company ("Iridium"), IRIDIUM CAPITAL CORPORATION, a
Delaware corporation ("Capital" and, together with Iridium, the "Note Issuers"),
as joint and several obligors, IRIDIUM ROAMING LLC, IRIDIUM IP LLC and IRIDIUM
FACILITIES CORPORATION, as guarantors hereunder (the "Initial Guarantors", and
together with the Note Issuers, the "Issuers") and STATE STREET BANK AND TRUST
COMPANY, a Massachusetts bank and trust company (the "Trustee").

            Each party agrees as follows for the benefit of the other parties
and for the equal and ratable benefit of the Holders of the Note Issuers' __%
Senior Notes due 2005, Series D (the "Notes").

                             RECITALS OF THE ISSUERS

            The Issuers have duly authorized the execution and delivery of this
Indenture to provide for the issuance of $350,000,000 aggregate principal amount
of the Notes issuable as provided in this Indenture. Pursuant to the terms of an
Underwriting Agreement dated _______ __, 1998 (the "Underwriting Agreement")
among the Issuers, Chase Securities Inc., Barclays Capital Inc. and Merrill
Lynch, Pierce, Fenner & Smith Incorporated, the Note Issuers have agreed to
issue and sell up to $350,000,000 aggregate principal amount of the Notes. All
things necessary to make this Indenture a valid agreement of the Issuers, in
accordance with its terms, have been done, and the Issuers have done all things
necessary to make the Notes, when executed by the Issuers and authenticated and
delivered by the Trustee hereunder and duly issued by the Issuers, the valid
obligations of the Issuers as hereinafter provided.

            For and in consideration of the premises and the purchase of the
Notes by the Holders thereof, it is mutually covenanted and agreed, for the
equal and proportionate benefit of all Holders, as follows:

                                    ARTICLE I

                   Definitions and Incorporation by Reference


            SECTION 1.01. Definitions.

            "Acquired Indebtedness" means, with respect to any specified Person,
(i) Indebtedness of any other Person existing at the time such Person merges
with or into or consolidates with or becomes a Restricted Subsidiary of such
specified Person and (ii) Indebtedness secured by a Lien encumbering any asset
acquired by such specified Person, which Indebtedness or Lien was not Incurred
in anticipation of, and was outstanding prior to, such merger, consolidation or
acquisition.

            "Affiliate" of any specified Person means any other Person directly
or indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"control" when used with respect to any Person means the power to direct the
management and policies of such Person, directly or indirectly, whether through
the ownership of Voting Stock, by contract or otherwise; provided, however, that
beneficial ownership of 10% or more of the Voting Stock of a Person shall be
deemed to be control. The terms "controlling" and "controlled" have meanings
correlative to the foregoing. Notwithstanding the foregoing, (a) no individual
shall be an Affiliate of Iridium solely by reason of his or her being a
director, officer or employee of IWCL, Iridium or any Subsidiary of either and
(b) none of the Restricted Subsidiaries shall be Affiliates of Iridium.

            "Agreement Regarding Guarantee" means the Second Agreement Regarding
Guarantee among Iridum LLC, Iridium and Motorola, dated as of April 1998,
as amended and restated as of July 11, 1997, and as further amended from time to
time.

            "Asset Disposition" means any transfer, conveyance, sale, lease or
other disposition (collectively, any "disposition") by Iridium or any Restricted
Subsidiary (including any disposition by means of a consolidation, merger or
similar transaction) but excluding a disposition by a Restricted Subsidiary to
Iridium or a Wholly-Owned Restricted Subsidiary or by Iridium to a Wholly-Owned
Restricted Subsidiary of (i) shares of Capital Stock of a 
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Restricted Subsidiary, (ii) all or substantially all of the assets of Iridium or
any Restricted Subsidiary representing a division or line of business or (iii)
other assets or rights of Iridium or any of its Restricted Subsidiaries other
than a disposition (a) in the ordinary course of business, (b) that constitutes
a Restricted Payment which is permitted under Section 4.04, (c) that is subject
to Article V herein, or (d) that constitutes the grant, establishment or
exercise of any Lien permitted pursuant to Section 4.12; provided, however, that
a transaction described in clauses (i), (ii) and (iii) shall constitute an Asset
Disposition only to the extent that the aggregate consideration for all such
transfers, conveyances, sales, leases or other dispositions exceeds $10,000,000
in any 12-month period.

            "Asset Drop-Down Transaction" means the transfer of substantially
all of the assets and liabilities of Iridium LLC to Iridium pursuant to an Asset
Transfer Agreement dated December 18, 1997.

            "Attributable Indebtedness" in respect of a Sale and Leaseback
Transaction means, as at the time of determination, the present value
(discounted at the interest rate borne by the Notes, compounded annually) of the
total obligations of the lessee for rental payments during the remaining term of
the lease included in such Sale and Leaseback Transaction (including any period
for which such lease has been extended).

            "Average Life" means, as of the date of determination, with respect
to any Indebtedness, the quotient obtained by dividing (i) the sum of the
products of the numbers of years from the date of determination to the dates of
each successive scheduled principal payment of such Indebtedness (or scheduled
redemption or similar payment with respect to Disqualified Stock) multiplied by
the amount of such payment by (ii) the sum of all such payments.

            "Bank Credit Agreement" means any one or more credit agreements
(which may include or consist of revolving credit agreements or similar
arrangements) between Iridium and/or any Subsidiary and one or more banks or
other financial institutions providing financing for the business of Iridium and
its Subsidiaries, and as any such agreement may be amended from time to time.
The Guaranteed Bank Facility shall be, and the Secured Bank Facility (when
executed and delivered by all the parties thereto) shall be, Bank Credit
Agreements.

            "Board of Directors" means the Board of Directors of Iridium or any
committee thereof duly authorized to act on behalf of such Board.

            "Build-out" means the construction, acquisition, improvement,
operation and development (including all costs related thereto) of the IRIDIUM
System up to the occurrence of Commercial Activation and the construction,
acquisition, improvement and development (including all costs related thereto)
thereafter of contemplated enhancements to the IRIDIUM System described in the
Prospectus.

            "Business Day" means a day other than a Saturday, Sunday or other
day on which banking institutions in Massachusetts or New York State are
authorized or required by law to close.

            "Capital" means Iridium Capital Corporation, a Delaware corporation,
and any successor Person to Capital.

            "Capital Lease Obligation" means an obligation that is required to
be classified and accounted for as a capitalized lease for financial reporting
purposes in accordance with GAAP. The amount of Indebtedness represented by a
Capital Lease Obligation will be the capitalized amount of such obligation
determined in accordance with GAAP, and the Stated Maturity thereof will be the
date of the last scheduled payment of rent or any other amount due under the
relevant lease prior to the first date upon which such lease may be terminated
by the lessee without payment of a penalty.

            "Capital Stock" of any Person means (i) in the case of a
corporation, corporate stock issued by such Person, (ii) in the case of an
association or business entity, any and all shares, interests, participations,
rights or other equivalents (however designated) of corporate stock issued by
such Person, (iii) in the case of a partnership, partnership interests (whether
general or limited) issued by such Person, (iv) in the case of a limited
liability company, membership interests issued by such Person, (v) any other
interest or participation that confers on another Person the right to receive a
share of the profits and losses of, or distributions of assets of, the issuing
Person, and 
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                                                                               3


(vi) any rights (other than debt securities convertible into, or exchangeable
for, Capital Stock), warrants or options to purchase any of the foregoing.

            "Change of Control" means the occurrence of any of the following:

            (a) one or more Dispositions which cause the amount of Motorola's
      Holdings of the Capital Stock of Iridium to be reduced by more than 50% as
      compared to Motorola's direct holding of Capital Stock in Iridium as of
      July 16, 1997 (in each such case without giving effect to any rights,
      warrants or options to purchase Capital Stock of Iridium, unless exercised
      prior thereto);

            (b) the first day on which Iridium fails to own, of record and
      beneficially, 100% of the Capital Stock of Capital (other than directors'
      qualifying shares);

            (c) any sale, lease, or other transfer (in one transaction or in a
      series of related transactions) is made by Iridium or its Restricted
      Subsidiaries of all or substantially all of the assets of Iridium and its
      Restricted Subsidiaries to any Person; or

            (d) the adoption of a plan relating to the liquidation or 
      dissolution of Iridium or Capital.

      Notwithstanding the foregoing, a Change in Control shall not be deemed to
result from (x) the acquisition by IWCL, Motorola or any wholly owned subsidiary
of Motorola of substantially all the assets of Iridium or Iridium LLC, 
(y) any transfer of assets or merger reversing the Asset Drop-Down Transition 
or (z) the merger of Iridium LLC or Iridium with and into IWCL, Motorola or 
any wholly owned subsidiary of Motorola.

            "Code" means the Internal Revenue Code of 1986, as amended.

            "Commercial Activation" means the date on which Iridium commences
generally available commercial service on the IRIDIUM System.

            "Consolidated Cash Flow" of Iridium means for any period the
Consolidated Net Income of Iridium and the consolidated Restricted Subsidiaries
for such period increased by (i) Consolidated Interest Expense of Iridium and
the consolidated Restricted Subsidiaries for such period, plus (ii) Consolidated
Income Tax Expense of Iridium and the consolidated Restricted Subsidiaries for
such period, plus (iii) the consolidated depreciation and amortization expense
included in the income statement of Iridium and the consolidated Restricted
Subsidiaries for such period (including any depreciation of any asset that
represents depreciation in respect of previously capitalized interest), plus
(iv) other non-cash charges of Iridium and the consolidated Restricted
Subsidiaries for such period deducted from consolidated revenues in determining
Consolidated Net Income for such period, minus (v) non-cash items of Iridium and
the consolidated Restricted Subsidiaries for such period which increased
consolidated revenues in determining Consolidated Net Income for such period,
minus (vi) the consolidated amortization expense related to payments made by
Iridium and the Restricted Subsidiaries to Motorola pursuant to the Operations
and Maintenance Contract included in the income statement of Iridium and the
consolidated Restricted Subsidiaries for such period.

            "Consolidated Income Tax Expense" of any Person means for any period
the consolidated provision for income taxes of such Person and its consolidated
Restricted Subsidiaries for such period determined on a consolidated basis in
accordance with GAAP or, so long as such Person is treated as a partnership or
other pass through entity for United States federal income tax purposes, the Tax
Amount paid by such Person during such period.

            "Consolidated Interest Expense" for any Person means for any period
the consolidated interest expense included in a consolidated income statement
(without deduction of interest income) of such Person and its consolidated
Restricted Subsidiaries for such period determined on a consolidated basis in
accordance with GAAP, including without limitation or duplication (or, to the
extent not so included, with the addition of), (i) the amortization of
Indebtedness discounts; (ii) any payments or fees with respect to letters of
credit, bankers' acceptances or similar facilities; (iii) fees with respect to
Interest Rate or Currency Protection Agreements; (iv) Preferred Stock dividends
of such Person (other than with respect to Disqualified Stock) declared and paid
or 
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                                                                               4


payable; (v) accrued Disqualified Stock dividends of such Person and all
Restricted Subsidiaries of such Person, whether or not declared or paid; (vi)
interest on Indebtedness Guaranteed by such Person; (vii) the portion of any
rental obligation allocable to interest expense; and (viii) capitalized
interest.

            "Consolidated Net Income" of any Person means for any period the
consolidated net income (or loss) of such Person and its consolidated Restricted
Subsidiaries for such period determined on a consolidated basis in accordance
with GAAP; provided, however, that there is excluded therefrom (to the extent
not already excluded therefrom) (i) the net income (or loss) of any Person
acquired by such Person or a Restricted Subsidiary of such Person in a
pooling-of-interests transaction for any period prior to the date of such
transaction, (ii) the net income (but not the net loss) of any Restricted
Subsidiary of such Person which Restricted Subsidiary is subject to restrictions
which prevent the payment of dividends or the making of distributions to such
Person, but only to the extent of such restrictions, (iii) the net income (or
loss) of any Person that is not a Restricted Subsidiary (including any
Unrestricted Subsidiary) except to the extent of the amount of dividends or
other distributions actually paid to such Person by such other Person during
such period, (iv) gains or losses on Asset Dispositions by Iridium or any
Restricted Subsidiary, (v) all extraordinary gains and losses, (vi) the
cumulative effect of changes in accounting principles in the year of adoption of
such changes, (vii) non-cash gains or losses resulting from fluctuations in
currency exchange rates, and (viii) the tax effect of any of the items described
in clauses (i) through (vii) above; provided further, however, that for purposes
of any determination pursuant to Section 4.04, there shall be deducted from the
Consolidated Net Income of Iridium and the Restricted Subsidiaries for such
period an amount equal to the Tax Amount paid by Iridium during such period.

            "Consolidated Net Worth" of any Person means the consolidated
stockholders' equity of such Person and its consolidated Restricted Subsidiaries
determined on a consolidated basis in accordance with GAAP, less amounts
attributable to Disqualified Stock of such Person; provided, however, that, with
respect to Iridium, adjustments following the date of the Indenture to the
accounting books and records of Iridium in accordance with Accounting Principles
Board Opinions Nos. 16 and 17 (or successor opinions thereto) or otherwise
resulting from the acquisition of control of Iridium by another Person shall not
be given effect to.

            "Consolidation" means the consolidation of the accounts of each of
the Restricted Subsidiaries with those of the Issuers in accordance with GAAP
consistently applied; provided, however, that "Consolidation" shall not include
consolidation of the accounts of any Unrestricted Subsidiary, but the interest
of the Issuers or any Restricted Subsidiary in an Unrestricted Subsidiary shall
be accounted for as an investment. The term "Consolidated" or "consolidated" has
a correlative meaning.

            "Debt to Capital Ratio" means on any date of determination for
Iridium and its Restricted Subsidiaries, on a consolidated basis, the ratio
(expressed as a percentage) of Outstanding Indebtedness on such date to Total
Invested Capital on such date.

            "Debt to Cash Flow Ratio" means on any date of determination (the
"Determination Date") for Iridium and its Restricted Subsidiaries, on a
consolidated basis, the ratio of Outstanding Indebtedness on the Determination
Date to Consolidated Cash Flow for the four most recently completed fiscal
quarters immediately preceding the Determination Date (the "Measurement Period")
determined on a pro forma basis as if any Indebtedness to be Incurred had been
Incurred and the proceeds thereof had been applied on the first day of the
Measurement Period; provided, however, that in making such computations, (i) the
Consolidated Interest Expense attributable to interest on any proposed
Indebtedness bearing a floating interest rate shall be computed on a pro forma
basis as if the rate in effect on such Determination Date had been the
applicable rate for the entire Measurement Period, (ii) the Consolidated
Interest Expense attributable to interest on any Indebtedness under a revolving
credit facility shall be computed based upon the average daily balance of such
Indebtedness during such Measurement Period, (iii) in the event Iridium or any
of its Restricted Subsidiaries has made asset dispositions or acquisitions of
assets not in the ordinary course of business (including acquisitions of other
Persons by merger, consolidation or purchase of Capital Stock) or has repaid
Indebtedness or Incurred additional Indebtedness during or after such
Measurement Period, such computation shall be made on a pro forma basis as if
the asset dispositions, acquisitions, repayment or incurrence had taken place on
the first day of such Measurement Period, (iv) the net proceeds of the
Indebtedness to be Incurred shall be deemed to have been applied on the first
day of such Measurement Period to acquire direct obligations of the United
States government having a maturity most closely approximating the maturity of
the Indebtedness to be incurred (or Indebtedness incurred during or after such
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                                                                               5


Measurement Period); provided, however, that the adjustment in this clause (iv)
shall not be made if, and to the extent, that application of such net proceeds
has otherwise been fully reflected in the computation, and (v) the actual
application of the net proceeds of Indebtedness Incurred during or after such
Measurement Period shall be given pro forma effect as if such application had
taken place on the first day of such Measurement Period.

            "Default" means an event that is, or after the passing of time or
the giving of notice or both would be, an Event of Default.

            "Definitive Notes" means Notes that are in the form of Exhibit A
attached hereto that do not include the information called for by footnote 1
thereof.

            "Depositary" means, with respect to the Notes issuable or issued in
whole or in part in global form, the Person specified in Section 2.03 as the
Depositary with respect to the Notes, until a successor shall have been
appointed and becomes such pursuant to the applicable provisions of this
Indenture, and thereafter, "Depositary" shall mean or include such successor.

            "Disposition" means (i) the sale, transfer or other conveyance by
Motorola or any of its Subsidiaries (other than to a wholly owned Subsidiary of
Motorola) of (a) Iridium LLC's membership interests or (b) equity interests in
any entity (an "intermediate entity") which owns, directly or indirectly,
Iridium's membership interests or (ii) the issue and sale by any such
intermediate entity of its equity securities to one or more third parties if and
to the extent the proceeds of such issue and sale are distributed by such
intermediate entity to Motorola or any of its Subsidiaries.

            "Disqualified Stock" of any Person means any Capital Stock of such
Person which, by its terms (or by the terms of any security into which it is
convertible or for which it is exchangeable at the option of the holder
thereof), or upon the happening of any event, (i) matures or is mandatorily
redeemable, pursuant to a sinking fund obligation or otherwise, (ii) is
convertible or exchangeable for Indebtedness or Disqualified Stock, or (iii) is
redeemable at the option of the holder thereof, in whole or in part, in each
case on or prior to the earlier of the Stated Maturity of the Notes or the date
on which no Notes remain outstanding. Disqualified Stock does not include any
Capital Stock that is not otherwise Disqualified Stock if by its terms the
holders have the right to require the issuer to repurchase such stock upon a
Change of Control (or upon events substantially similar to a Change of Control).

            "Eligible Institution" means a commercial banking institution that
has combined capital and surplus of not less than $500 million or its equivalent
in foreign currency, whose debt is rated "A-3" or higher or "A-" or higher
according to Moody's Investors Service, Inc. or Standard & Poor's Ratings Group
(or such similar equivalent rating by at least one "nationally recognized
statistical rating organization" (as defined in Rule 436 under the Securities
Act)) respectively, at the time as of which any investment or rollover therein
is made.

            "Equity Offering" means an offering made on a primary basis of
Capital Stock (other than Disqualified Stock) of IWCL or Iridium that results in
Net Cash Proceeds to IWCL or Iridium, as the case may be, provided, however, if
any such offering is an offering of the Capital Stock of IWCL, only the Net Cash
Proceeds thereof that are contributed to Iridium shall be taken into
consideration for the purposes of this definition.

            "Exchange Act" means the Securities Exchange Act of 1934, as amended
(or any successor act) and the rules and regulations thereunder.

            "Existing Affiliate Agreements" means (i) the Space System Contract,
(ii) the Terrestrial Network Development Contract, (iii) the Operations and
Maintenance Contract, (iv) the Agreement Regarding Guarantee, (v) the Interest
Exchange Agreement, (vi) the Share Issuance Agreement, (vii) the Management
Services Agreement, (viii) the Motorola MOU and any subordination agreement
contemplated thereunder, (ix) the agreement or agreements among Iridium,
Motorola and other parties thereto providing for the development, manufacture
and sale of individual subscriber equipment to be used in the IRIDIUM System,
which agreement or agreements are to be executed and delivered after the Issue
Date as a condition to borrowings under the Secured Bank Facility, and (x) any
other agreements with Affiliates or Related Persons of Iridium, existing on the
Issue Date and listed on Schedule I to this Indenture.
   11
                                                                               6


            "Foreign Subsidiary" means, with respect to any Person, any
Subsidiary of such Person which is incorporated or otherwise organized under the
laws of any jurisdiction other than the United States of America, any state
thereof or the District of Columbia and substantially all of whose consolidated
assets are located primarily outside of the United States of America.

            "GAAP" means generally accepted accounting principles in the United
States of America as in effect as of the Issue Date, including those set forth
in (i) the opinions and pronouncements of the Accounting Principles Board of the
American Institute of Certified Public Accountants, (ii) statements and
pronouncements of the Financial Accounting Standards Board, (iii) such other
statements by such other entity as approved by a significant segment of the
accounting profession and (iv) the rules and regulations of the SEC governing
the inclusion of financial statements (including pro forma financial statements)
in periodic reports required to be filed pursuant to Section 13 of the Exchange
Act, including opinions and pronouncements in staff accounting bulletins and
similar written statements from the accounting staff of the SEC. All ratios and
computations based on GAAP contained in the Indenture shall be computed in
conformity with GAAP.

            "Global Note" means a Note that is in the form of Exhibit A hereto
that includes the information called for by footnote 1 thereof.

            "Government Securities" means direct obligations of, or obligations
guaranteed by, the United States of America for the payment of which obligations
or guarantee the full faith and credit of the United States is pledged and which
have a remaining weighted Average Life to maturity of not more than one year
from the date of Investment therein.

            "Guarantee" means any obligation, contingent or otherwise, of any
Person directly or indirectly guaranteeing any Indebtedness of any other Person
(the "primary obligor") through an agreement enforceable by or for the benefit
of the holder of such Indebtedness and any such obligation, direct or indirect,
contingent or otherwise, of such Person (i) to purchase or pay (or advance or
supply funds for the purchase or payment of) such Indebtedness, (ii) to purchase
property, securities or services for the purpose of assuring the holder of such
Indebtedness of the payment of such Indebtedness, (iii) to maintain working
capital, equity capital or other financial statement condition or liquidity of
the primary obligor so as to enable the primary obligor to pay such
Indebtedness, or (iv) to act as a co-obligor with such Person on its
Indebtedness (and "Guaranteed" and "Guaranteeing" shall have meanings
correlative to the foregoing); provided, however, that the Guarantee by any
Person shall not include endorsements by such Person for collection or deposit,
in either case, in the ordinary course of business.

            "Guaranteed Bank Facility" means the credit facility established by
the credit agreement dated as of August 21, 1996 by and among Iridium, as
successor to Iridium LLC, and certain lenders providing for an unsecured $750
million revolving credit facility, as amended from time to time.

            "Guarantor Subsidiary" means any Person that has issued a Subsidiary
Guaranty by execution and delivery of this Indenture, including each of the
Initial Guarantors.

            "Holders" means the registered holders from time to time of the
Notes.

            "Incur" means, with respect to any Indebtedness or other obligation
of any Person, to create, issue, incur (by conversion, exchange or otherwise),
assume, Guarantee or otherwise become liable in respect of such Indebtedness or
other obligation including by acquisition of Subsidiaries or the recording, as
required pursuant to GAAP or otherwise, of any such Indebtedness or other
obligation on the balance sheet of such Person (and "Incurrence", "Incurred" and
"Incurring" have meanings correlative to the foregoing); provided, however, that
a change in GAAP that results in an obligation of such Person that exists at
such time becoming Indebtedness shall not be deemed an Incurrence of such
Indebtedness and that neither the accrual of interest nor the accretion of
original issue discount shall be deemed an Incurrence of Indebtedness.
Notwithstanding the foregoing, Iridium may elect to treat all or any portion of
revolving credit debt of Iridium or a Subsidiary as being Incurred from and
after any date beginning the date the revolving credit commitment is extended to
Iridium or a Subsidiary, by furnishing notice thereof to the Trustee, and any
borrowings or reborrowings by Iridium or a Subsidiary under such commitment up
to the amount of such commitment designated by Iridium as Incurred shall not be
deemed to be new Incurrences of Indebtedness by Iridium or such Subsidiary;
provided, however, that in such event the undrawn portion of any such 
   12
                                                                               7


revolving credit debt shall be deemed to be outstanding Indebtedness until such
time as the commitment thereunder is terminated. The accretion of principal of a
non-interest bearing or other discount security shall not be deemed the
Incurrence of Indebtedness.

            "Indebtedness" means (without duplication), with respect to any
Person, whether recourse is to all or a portion of the assets of such Person and
whether or not contingent, (i) every obligation of such Person for money
borrowed, (ii) every obligation of such Person evidenced by bonds, debentures,
notes or other similar instruments, including any such obligations Incurred in
connection with the acquisition of property, assets or businesses, (iii) every
reimbursement obligation of such Person with respect to letters of credit,
bankers' acceptances or similar facilities issued for the account of such
Person, (iv) every obligation of such Person issued or assumed as the deferred
purchase price of property or services (including securities repurchase
agreements but excluding trade accounts payable or accrued liabilities arising
in the ordinary course of business which are not overdue by more than 30 days or
which are being contested in good faith), (v) every Capital Lease Obligation of
such Person, (vi) all Receivables Sales of such Person, together with any
obligation of such Person to pay any discount, interest, fees, indemnities,
penalties, recourse, expenses or other amounts in connection therewith, (vii)
all obligations to redeem or repurchase outstanding Disqualified Stock issued by
such Person, (viii) all Attributable Indebtedness, (ix) every obligation under
Interest Rate or Currency Protection Agreements of such Person, (x) every
obligation of the type referred to in clauses (i) through (ix) of another Person
secured by any Lien on any property or asset of such Person (whether or not such
obligation is assumed by such Person), the amount of such obligation being
deemed to be the lesser of the fair market value of such property or assets and
the amount of the obligation so secured and (xi) every obligation of the type
referred to in clauses (i) through (x) of another Person and all dividends of
another Person the payment of which, in either case, such Person has Guaranteed.
The "amount" or "principal amount" of Indebtedness at any time of determination
as used herein represented by (a) any Indebtedness issued at a price that is
less than the principal amount at maturity thereof, shall be the amount of the
liability in respect thereof determined in accordance with GAAP, (b) any
Receivables Sale, shall be the amount of the unrecovered capital or principal
investment of the purchaser (other than Iridium or a Wholly-Owned Restricted
Subsidiary) thereof, excluding amounts representative of yield or interest
earned on such investment, (c) any Disqualified Stock, shall be the maximum
fixed redemption or repurchase price in respect thereof, (d) any Capital Lease
Obligation, shall be determined in accordance with the definition thereof and
(e) any Permitted Interest Rate or Currency Protection Agreement, shall be zero.
In no event shall Indebtedness include any liability for taxes. For purposes of
determining any particular amount of Indebtedness, Guarantees or Liens with
respect to letters of credit supporting Indebtedness otherwise included in the
determination of a particular amount shall not be included. The term
"Indebtedness" does not include any obligations of Iridium or any Restricted
Subsidiary (x) under the Space System Contract, the Operations and Maintenance
Contract or the Terrestrial Network Development Contract (including any agreed
upon deferrals of payment obligations thereunder) or (y) in respect of amounts
owing to gateway operators and other service providers in connection with the
clearinghouse system to be established and operated by Iridium (as described
under "Business--The IRIDIUM System--Business Support Systems" in the
Prospectus).

            "Independent Financial Advisor" means an accounting, appraisal or
investment banking firm of nationally recognized standing that is, in the
judgment of the Board of Directors, qualified to perform the task for which it
has been engaged and disinterested and independent with respect to the Note
Issuers and their Subsidiaries and Affiliates.

            "Indenture" means this Indenture as amended or supplemented from
time to time.

            "Initial Guarantors" means Iridium Roaming LLC and Iridium IP LLC,
each a Delaware limited liability company, and Iridium Facilities Corporation, a
Delaware corporation.

            "Interest Exchange Agreement" means the Interest Exchange Agreement
among Iridium LLC and IWCL, dated June 9, 1997, as amended from time to time.

            "Interest Rate or Currency Protection Agreement" of any Person means
any forward contract, futures contract, swap, option or other financial
agreement or arrangement (including, without limitation, caps, floors, collars
and similar agreements) relating to, or the value of which is dependent upon,
interest rates or currency exchange rates or indices.
   13
                                                                               8


            "Investment" by any Person means any direct or indirect loan,
advance or other extension of credit or capital contribution (by means of
transfers of cash or other property to others or payments for property or
services for the account or use of others, or otherwise) to, or purchase or
acquisition of Capital Stock, bonds, notes, debentures or other securities or
evidence of Indebtedness issued by, any other Person, including any payment on a
Guarantee of any obligation of such other Person, but excluding any loan,
advance or extension of credit to an employee of Iridium or any Restricted
Subsidiary in the ordinary course of business, accounts receivable and other
commercially reasonable extensions of trade credit. A delay in the purchase of
any of Iridium's Capital Stock under a purchase or similar agreement shall not
be deemed to be an Investment by Iridium in the purchaser.

            "Investment Grade Rating" means a rating equal to or higher than
"Baa3" (or the equivalent) by Moody's Investors Service, Inc. (or any successor
to the rating agency business thereof) and "BBB-" (or the equivalent) by
Standard & Poor's Ratings Group (or any successor to the rating agency business
thereof).

            "Iridium" means Iridium Operating LLC, a Delaware limited liability
company, and any successor Person to Iridium Operating LLC.

            "Iridium LLC" means Iridium LLC, a Delaware limited liability
company, and any successor Person to Iridium LLC.

            "Iridium Operating LLC Agreement" means the Limited Liability
Agreement of Iridium, dated as of December 18, 1997, as amended from time to
time.

            "IRIDIUM System" means Iridium's global mobile wireless
communications system as described in the Prospectus.

            "Issue Date" means the date on which the Notes are first issued
and delivered.

            "Issuers" means the parties named as such in this Indenture until a
successor replaces one or more of such parties pursuant to the applicable
provisions of this Indenture and, thereafter, includes such successor and, for
purposes of any provision contained herein and required by the TIA, each other
obligor on the indenture securities (within the meaning of the TIA). In
particular, upon execution and delivery of this Indenture, the "Issuers" shall
mean Iridium, Capital and the Initial Guarantors.

            "IWCL" means Iridium World Communication Ltd., a Bermuda company,
and any successor Person to IWCL.

            "Lien" means, with respect to any property or assets, any mortgage
or deed of trust, pledge, hypothecation, assignment, Receivables Sale, deposit
arrangement, security interest, lien, charge, easement (other than any easement
not materially impairing usefulness or marketability), encumbrance, preference,
priority or other security agreement or preferential arrangement of any kind or
nature whatsoever on or with respect to such property or assets (including,
without limitation, any conditional sale or other title retention agreement
having substantially the same economic effect as any of the foregoing or any
Sale and Leaseback Transaction).

            "LLC Agreement" means the Limited Liability Company Agreement of
Iridium LLC, dated as of July 29, 1996, as amended from time to time.

            "Management Services Agreement" means the Amended and Restated
Management Services Agreement among Iridium LLC, Iridium and IWCL, dated as
of December 18, 1997, as amended from time to time.

            "Marketable Securities" means: (i) Government Securities; (ii) any
time deposit account, money market deposit and certificate of deposit maturing
not more than 270 days after the date of acquisition issued by, or time deposit
of, an Eligible Institution; (iii) commercial paper maturing not more than 270
days after the date of acquisition issued by a corporation (other than an
Affiliate of Iridium) with a rating, at the time as of which any investment
therein is made, of "P-1" or higher according to Moody's Investors Service, Inc.
or "A-1" or higher according to Standard & Poor's Ratings Group (or such similar
equivalent rating by at least one "nationally recognized statistical rating
organization" (as defined in Rule 436 under the Securities Act)); (iv) any
banker's 
   14
                                                                               9


acceptances or money market deposit accounts issued or offered by an Eligible
Institution; (v) repurchase obligations with a term of not more than seven days
for Government Securities entered into with an Eligible Institution; and (vi)
any fund investing exclusively in investments of the types described in clauses
(i) through (v) above.

            "Master Subscription Agreement" means the Agreement between Iridium
LLC and IWCL, dated as of June 30, 1997, as amended from time to time, pursuant
to which IWCL has agreed to sell shares of its Class B Common Stock to Iridium
LLC.

            "Motorola" means Motorola, Inc., a Delaware corporation, and any
successor Person to Motorola.

            "Motorola Additional Guarantee" means the commitment by Motorola
pursuant to the Motorola MOU to guarantee up to an additional $350 million of
Indebtedness (inclusive of principal and interest), under the Guaranteed Bank
Facility or another credit agreement on identical terms, in excess of the
Motorola Guarantee.

            "Motorola Guarantee" means the guarantee by Motorola of up to $750
million of Indebtedness under the Guaranteed Bank Facility.

            "Motorola MOU" means the Amended and Restated Memorandum of
Understanding, dated as of April 1998, among Iridium LLC, Iridium and
Motorola, as amended from time to time.

            "Motorola's Holding of Capital Stock of Iridium" means the amount of
Capital Stock of Iridium LLC held directly by Motorola multiplied by the
percentage of Iridium LLC's direct or indirect holdings of the Capital Stock of
Iridium.

            "Net Available Proceeds" from any Asset Disposition by any Person
means cash or Marketable Securities received (including by way of sale or
discounting of a note, installment receivable or other receivable, but excluding
any other consideration received in the form of assumption by the acquiror of
Indebtedness or other obligations relating to such properties or assets)
therefrom by such Person, net of (i) all legal, title and recording tax
expenses, commissions and other fees and expenses incurred and all federal,
state, provincial, foreign and local taxes (including taxes payable upon payment
or other distribution of funds from a foreign subsidiary to Iridium or another
Subsidiary of Iridium) required to be accrued as a liability as a consequence of
such Asset Disposition, (ii) all payments made by such Person or its Restricted
Subsidiaries on any Indebtedness which is secured by such assets in accordance
with the terms of any Lien upon or with respect to such assets or which must by
the terms of such Lien, or in order to obtain a necessary consent to such Asset
Disposition or by applicable law, be repaid out of the proceeds from such Asset
Disposition, (iii) all distributions and other payments made to minority
interest holders in Restricted Subsidiaries of such Person or joint ventures as
a result of such Asset Disposition, (iv) appropriate amounts to be provided by
such Person or any Restricted Subsidiary thereof, as the case may be, as a
reserve in accordance with GAAP against any liabilities associated with such
assets and retained by such Person or any Restricted Subsidiary thereof, as the
case may be, after such Asset Disposition, including, without limitation,
liabilities under any indemnification obligations and severance and other
employee termination costs associated with such Asset Disposition, in each case
as determined by the Board of Directors, in its reasonable good faith judgment
evidenced by a resolution filed with the Trustee; provided, however, that any
reduction in such reserve within twelve months following the consummation of
such Asset Disposition will be treated for all purposes of this Indenture and
the Notes as a new Asset Disposition at the time of such reduction with Net
Available Proceeds equal to the amount of such reduction, and (v) any
consideration for an Asset Disposition (which would otherwise constitute Net
Available Proceeds) that is required to be held in escrow pending determination
of whether a purchase price adjustment will be made, but amounts under this
clause (v) will become Net Available Proceeds at such time and to the extent
such amounts are released to such Person.

            "Net Cash Proceeds," with respect to any issuance or sale of Capital
Stock, means the cash proceeds of such issuance or sale, net of attorneys' fees,
accountants' fees, underwriters' or placement agents' fees, discounts or
commissions and brokerage, consultant and other fees actually incurred in
connection with such issuance or sale and net of taxes paid or payable as a
result thereof.
   15
                                                                              10


            "Non-U.S. Person" means a Person who is not a U.S. Person, as
such term is defined in Rule 902 of the Securities Act.

            "Offer to Purchase" means a written offer (the "Offer") sent by the
Note Issuers by first class mail, postage prepaid, to each Holder at his address
appearing in the note register on the date of the Offer offering to purchase up
to the principal amount of Notes specified in such Offer at the purchase price
specified in such Offer (as determined in accordance with Section 4.06). Unless
otherwise required by applicable law, the Offer shall specify an expiration date
(the "Expiration Date") of the Offer to Purchase which shall be, subject to any
contrary requirements of applicable law, not less than 30 days or more than 60
days after the date of such Offer and a settlement date (the "Purchase Date")
for purchase of Notes within five Business Days after the Expiration Date. The
Note Issuers shall notify the Trustee in writing at least 15 Business Days (or
such shorter period as is acceptable to the Trustee) prior to the mailing of the
Offer of the Note Issuers' obligation to make an Offer to Purchase, and the
Offer shall be mailed by the Note Issuers or, at the Note Issuers' request, by
the Trustee in the name and at the expense of the Note Issuers. The Offer shall
contain information concerning the business of Iridium and its Subsidiaries
which Iridium in good faith believes shall enable such holders to make an
informed decision with respect to the Offer to Purchase (which at a minimum
shall include (i) the most recent annual and quarterly financial statements and
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" contained in the documents required to be filed with the Trustee
pursuant to this Indenture (which requirements may be satisfied by delivery of
such documents together with the Offer), (ii) a description of material
developments in Iridium's business subsequent to the date of the latest of such
financial statements referred to in clause (i) (including a description of the
events requiring Iridium to make the Offer to Purchase), (iii) if applicable,
appropriate pro forma financial information concerning the Offer to Purchase and
the events requiring Iridium to make the Offer to Purchase and (iv) any other
information required by applicable law to be included therein). The Offer shall
contain all instructions and materials necessary to enable such holders to
tender Notes pursuant to the Offer to Purchase.

            "Officer" means the Chairman of the Board, the Chief Executive
Officer, the Chief Financial Officer, the President, any Vice President, the
Treasurer, the Secretary or any Assistant Secretary of such Person.

            "Officers' Certificate" means a certificate signed by two
Officers.

            "Operations and Maintenance Contract" means the IRIDIUM System
Operations and Maintenance Contract between Iridium, as successor to Iridium
LLC, and Motorola, dated as of July 29, 1993, as amended from time to time.

            "Opinion of Counsel" means a written opinion from legal counsel who
is acceptable to the Trustee. The counsel may be an employee of or counsel to
Iridium.

            "Outstanding Indebtedness" means the aggregate consolidated
principal amount (or the accreted value in the case of any Indebtedness issued
at a discount) of Indebtedness of Iridium and its Restricted Subsidiaries, on a
consolidated basis, outstanding as of the date of determination.

            "pari passu", when used with respect to the ranking of any
Indebtedness of any Person in relation to other Indebtedness of such Person,
means that each such Indebtedness (a) either (i) is not subordinated in right of
payment to any other Indebtedness of such Person or (ii) is subordinate in right
of payment to the same Indebtedness of such Person as is the other and is so
subordinate to the same extent and (b) is not subordinate in right of payment to
the other or to any Indebtedness of such Person as to which the other is not so
subordinate.

            "Permitted Interest Rate or Currency Protection Agreement" of any
Person means any Interest Rate or Currency Protection Agreement entered into
with one or more financial institutions that is designed to protect such Person
against fluctuations in interest rates or currency exchange rates with respect
to Indebtedness Incurred and which shall have a notional amount no greater than
the payments due with respect to the Indebtedness being hedged thereby, or with
respect to obligations or receivables denominated in foreign currencies, and not
for purposes of speculation.

            "Permitted Investment" means an Investment by Iridium or any
Restricted Subsidiary (i) in any Person as a result of which such Person becomes
a Restricted Subsidiary, the primary business of which is to engage 
   16
                                                                              11


in all or a portion of a Related Business, (ii) in Marketable Securities, (iii)
in Permitted Interest Rate or Currency Protection Agreements, (iv) made as a
result of the receipt of noncash consideration from an Asset Disposition that
was made pursuant to and in compliance with Section 4.06 herein, (v) consisting
of loans or advances to employees of Iridium or any Restricted Subsidiary made
in the ordinary course of business not to exceed $2,000,000 in the aggregate
outstanding at any one time and (vi) in any Person for a purpose which is
related, ancillary or complementary to the businesses of Iridium and the
Restricted Subsidiaries on the date such Investment is made; provided that the
aggregate amount of Investments made pursuant to this clause (vi) and then
outstanding does not exceed $100,000,000. The amount of Investments outstanding
pursuant to clause (vi) of the prior sentence shall be included in the
calculation of the aggregate amount of Restricted Payments made since July 16,
1997 pursuant to Section 4.04.

            "Permitted Liens" means:

                  (i) Prior to Commercial Activation, Liens to secure up to
            $750,000,000 in principal amount of Indebtedness permitted to be
            incurred pursuant to Section 4.03(b)(i);

                  (ii) After Commercial Activation, Liens to secure up to
            $1,700,000,000 in principal amount of Indebtedness (inclusive of the
            Indebtedness secured by the Liens described in clause (i) above and
            any secured Indebtedness which refinanced such Indebtedness)
            permitted to be Incurred pursuant to Section 4.03;

                  (iii) Liens in favor of Holders of the Notes, the holders of 
            the Exchange Notes and the Trustee;

                  (iv) Liens in favor of the Issuers or a Wholly-Owned 
            Restricted Subsidiary;

                  (v) Liens on property at the time such Person or any of its
            Subsidiaries acquires such property, including any acquisition by
            means of a merger or consolidation with or into such Person or a
            Subsidiary of such Person, other than any property delivered
            pursuant to the Space System Contract or the Operations and
            Maintenance Contract; provided, however, that such Liens are not
            created, incurred or assumed in connection with, or in contemplation
            of, such acquisition; provided further, however, that the Liens may
            not extend to any other property owned by such Person or any of its
            Subsidiaries;

                  (vi) other than in connection with Indebtedness, any Lien
            arising in the ordinary course of business (a) to secure payments of
            workers' compensation, unemployment insurance, pension or other
            social security or retirement benefits, or to secure the performance
            of bids, tenders, leases, progress payments, contracts (other than
            for the payment of money) or to secure public or statutory
            obligations of Iridium or any Restricted Subsidiary, or to secure
            surety or appeal bonds to which Iridium or any Restricted Subsidiary
            is a party, (b) imposed by law dealing with materialmen's,
            mechanics', workmen's, repairmen's, warehousemen's landlords',
            vendors' or carriers' Liens created by law, or deposits or pledges
            which are not yet due or, if due, the validity of which is being
            contested in good faith by Iridium or any Restricted Subsidiary by
            appropriate proceedings promptly instituted and diligently conducted
            and against which Iridium has established appropriate reserves in
            accordance with GAAP, (c) rights of financial institutions to set
            off and chargeback arising by operation of law, (d) rights, if any,
            of gateway operators and other service providers to setoff and
            chargeback arising under agreements between Iridium and any such
            Person in respect of clearinghouse services provided by Iridium to
            such Person, and (e) similar Liens;

                  (vii) servitudes, licenses, easements, encumbrances,
            restrictions, rights-of-way and rights in the nature of easements or
            similar charges which shall not in the aggregate materially
            adversely impair the use of the subject property by Iridium or a
            Restricted Subsidiary;
   17
                                                                              12


                  (viii) zoning and building by-laws and ordinances, municipal
            bylaws and regulations, and restrictive covenants, which do not
            materially interfere with the use of the subject property by Iridium
            or a Restricted Subsidiary;

                  (ix) Liens to secure the performance of statutory obligations,
            surety or appeal bonds, performance bonds or other obligations of a
            like nature incurred in the ordinary course of business;

                  (x) Liens existing on the Issue Date;

                  (xi) Liens for taxes, assessments or governmental charges or
            claims that are not yet delinquent or that are being contested in
            good faith by appropriate proceedings promptly instituted and
            diligently concluded; provided, however, that any reserve or other
            appropriate provision as shall be required in conformity with GAAP
            shall have been made therefor;

                  (xii) any interest in or title of a lessor to any property
            subject to a Capital Lease Obligation which is permitted under this
            Indenture; and

                  (xiii) Liens incurred in the ordinary course of business of
            the Issuers and the Restricted Subsidiaries with respect to
            obligations that do not exceed $10,000,000 at any one time
            outstanding and that:

                        (a) are not incurred in connection with the borrowing of
                  money or the obtaining of advances or credit (other than trade
                  credit in the ordinary course of business); and

                        (b) do not in the aggregate materially detract from the
                  value of the property or materially impair the use thereof in
                  the operation of business by Iridium and the Restricted
                  Subsidiaries.

            "Person" means any individual, corporation, partnership, limited
liability company, joint venture, association, joint stock company, trust,
unincorporated organization, government or any agency or political subdivision
thereof or any other entity.

            "Preferred Stock" of any Person means Capital Stock of such Person
of any class or classes (however designated) that ranks prior, as to the payment
of dividends or as to the distribution of assets upon any voluntary or
involuntary liquidation, dissolution or winding up of such Person, to shares of
Capital Stock of any other class of such Person.

            "principal" of a Note means the principal of the Note plus the
premium, if any, payable on the Note that is due or overdue or is to become due
at the relevant time (except when used in Section 2.02 hereof).

            "Prospectus" means the prospectus, dated ________ __, 1998, relating
to the offering of the Notes.

            "Ratings Agencies" means Standard & Poor's Rating Group and
Moody's Investors Services, Inc. or any successor to the respective credit
rating businesses thereof.

            "Receivables" means receivables, chattel paper, instruments,
documents or intangibles evidencing or relating to the right to payment of money
in respect of the sale of goods or services.

            "Receivables Sale" of any Person means any sale of Receivables of
such Person (pursuant to a purchase facility or otherwise), other than (x) any
sale of Receivables by such Person as to which (i) such Person is neither
directly or indirectly liable (as guarantor or otherwise) nor provides credit
support of any kind and (ii) the purchaser of such Receivables has no recourse
to any assets or property of such Person or (y) in connection with a disposition
of the business operations of such Person relating thereto or a disposition of
defaulted Receivables for purpose of collection and not as a financing
arrangement.
   18
                                                                              13


            "Refinance" means, in respect of any Indebtedness, to refinance,
extend, renew, refund, repay, prepay, redeem, defease or retire, or to issue
other Indebtedness in exchange or replacement for, such Indebtedness.
"Refinanced" and "Refinancing" shall have correlative meanings.

            "Refinancing Indebtedness" means Indebtedness that Refinances any
Indebtedness of Iridium or any Restricted Subsidiary existing on the Issue Date
or Incurred in compliance with this Indenture, including Indebtedness that
Refinances Refinancing Indebtedness; provided, however, that except in the case
of a Refinancing of the Guaranteed Bank Facility after any extension thereof (as
contemplated by the Motorola MOU) (i) such Refinancing Indebtedness has a Stated
Maturity no earlier than the Stated Maturity of the Indebtedness being
Refinanced, (ii) such Refinancing Indebtedness has an Average Life at the time
such Refinancing Indebtedness is Incurred that is equal to or greater than the
Average Life of the Indebtedness being Refinanced, (iii) such Refinancing
Indebtedness has an aggregate principal amount (or if Incurred with original
issue discount, an aggregate issue price) that is equal to or less than the
aggregate principal amount (or if Incurred with original issue discount, the
aggregate accreted value) then outstanding or committed (plus accrued and unpaid
interest and fees and expenses, including any premium and defeasance costs)
under the Indebtedness being Refinanced and (iv) in the event the Indebtedness
being Refinanced constitutes a Subordinated Obligation, the Refinancing
Indebtedness is subordinated to the Notes to at least the same extent as the
Indebtedness being Refinanced; provided further, however, that Refinancing
Indebtedness shall not include Indebtedness of the Issuers or a Restricted
Subsidiary that Refinances Indebtedness of an Unrestricted Subsidiary.

            "Related Business" means the business of developing, owning,
engaging in and dealing with all or any part of the business of the provision of
telecommunications services and businesses and (i) reasonably related extensions
thereof, including but not limited to the manufacture, purchase, ownership,
operation, leasing, licensing, financing and selling of, and generally dealing
in or with, communications satellites, earth stations, gateways, ground
infrastructure and subscriber equipment, used or intended for use with
telecommunications services and businesses and (ii) any other activities that
are reasonably related to the provision of telecommunications services and
businesses.

            "Related Person" of any Person means any other Person directly or
indirectly owning (a) 5% or more of the outstanding Capital Stock of such Person
or (b) 5% or more of the combined voting power of the Voting Stock of such
Person.

            "Reserve Capital Call" means the agreement of each of Iridium LLC's
members to purchase additional Class I Interests in Iridium LLC pursuant to
Section 4.02 of the LLC Agreement.

            "Restricted Subsidiary" means any Subsidiary of Iridium, whether
existing on or after the Issue Date, unless such Subsidiary is an Unrestricted
Subsidiary.

            "Sale and Leaseback Transaction" means an arrangement relating to
property now owned or hereafter acquired by Iridium or a Restricted Subsidiary
whereby Iridium or such Restricted Subsidiary transfers such property to a
Person and Iridium or such Restricted Subsidiary leases it from such Person.

            "SEC" means the Securities and Exchange Commission and any
successor agency.

            "Secured Indebtedness" means any Indebtedness of either Note
Issuer secured by a Lien.  "Secured Indebtedness" of any Guarantor Subsidiary
has a correlative meaning.

            "Securities Act" means the Securities Act of 1933, as amended (or
any successor act) and the rules and regulations thereunder.

            "Share Issuance Agreement" means the Share Issuance Agreement
between Iridium LLC and IWCL, dated as of June 9, 1997, as amended from time to
time.

            "Significant Subsidiary" means a Restricted Subsidiary that is a
"significant subsidiary" as defined in Rule 1-02(w) of Regulation S-X under the
Securities Act and the Exchange Act as in effect on the Issue Date.
   19
                                                                              14


            "Space System Contract" means the Iridium Space System Contract
between Iridium, as successor to Iridium LLC, and Motorola, dated as of July 29,
1993, as amended from time to time.

            "Stated Maturity" means, with respect to any security, the date
specified in such security as the fixed date on which the final payment of
principal of such security is due and payable, including pursuant to any
mandatory redemption provision (but excluding any provision providing for the
repurchase of such security at the option of the holder thereof upon the
happening of any contingency unless such contingency has occurred).

            "Subordinated Obligation" means any Indebtedness of either Note
Issuer (whether outstanding on the Issue Date or thereafter Incurred) which is
subordinate or junior in right of payment to the Notes pursuant to a written
agreement to that effect. Iridium's 14-1/2% Senior Subordinated Notes due 2006
shall be Subordinated Obligations.

            "Subsidiary" of any Person means (i) a corporation more than 50% of
the combined voting power of the outstanding Voting Stock of which is owned,
directly or indirectly, by such Person or by one or more other Subsidiaries of
such Person or by such Person and one or more Subsidiaries of such Person or
(ii) any other Person (other than a corporation) in which such Person, or one or
more other Subsidiaries of such Person or such Person and one or more other
Subsidiaries of such Person, directly or indirectly, has at least a majority
ownership and power to direct the policies, management and affairs thereof.

            "Subsidiary Guaranty" means any Guarantee of the Notes which may
from time to time be executed and delivered pursuant to the terms of this
Indenture. Each such Subsidiary Guaranty shall be in the form prescribed in this
Indenture.

            "Tax Amount" means the aggregate amount of distributions required to
be made by (i) Iridium LLC to its members under Section 3.07(c) of the LLC
Agreement (or a successor provision relating to distributions by Iridium LLC
with respect to members' U.S. tax liability) or (ii) Iridium to its members
under the provisions in the Iridium Operating LLC Agreement corresponding to
Section 3.07(c) of the LLC Agreement (or a successor provision relating to
distributions by Iridium with respect to members' U.S. tax liability).
Notwithstanding anything to the contrary, Tax Amount shall not include taxes
resulting from Iridium LLC's or Iridium's reorganization as or change in the
status to a corporation.

            "Terrestrial Network Development Contract" means the Terrestrial
Network Development Contract between Iridium, as successor to Iridium LLC, and
Motorola, entered into June, 1995, as amended from time to time.

            "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. Sections
77aaa-77bbbb) as in effect on the date of this Indenture.

            "Total Invested Capital" means, as of any date of determination, the
sum of (a) Total Pro Forma Consolidated Indebtedness as of such date and (b)
$1,983,000,000 plus the aggregate proceeds received by Iridium or any Restricted
Subsidiary in respect of the issuance of Capital Stock of Iridium, including the
fair value of property other than cash (as determined in good faith by the Board
of Directors in a resolution filed with the Trustee), less any redemptions of,
or dividends or other distributions on, Capital Stock of Iridium (other than any
Tax Amount or any dividend or distribution in Capital Stock) made after the
Issue Date and on or prior to the date of determination.

            "Total Pro Forma Consolidated Indebtedness" means, as of any date of
determination, after giving effect to any Indebtedness to be Incurred by Iridium
and its Restricted Subsidiaries on a consolidated basis on such date and the
application of the proceeds therefrom, the aggregate amount of Outstanding
Indebtedness as of such date determined on a consolidated basis in accordance
with GAAP and which would appear on the consolidated balance sheet of Iridium.

            "Trustee" means the party named as such in this Indenture until a
successor replaces it and, thereafter, means the successor.
   20
                                                                              15


            "Trust Officer" means any officer or assistant officer of the
Trustee assigned by the Trustee to administer its corporate trust matters.

            "Uniform Commercial Code" means the New York Uniform Commercial Code
as in effect from time to time.

            "Unrestricted Subsidiary" means (i) any Subsidiary of Iridium
designated as such by the Board of Directors as set forth below where (a)
neither Iridium nor any of its other Subsidiaries (other than another
Unrestricted Subsidiary) (1) provides credit support for, or Guarantee of, any
Indebtedness of such Subsidiary or any Subsidiary of such Subsidiary (including
any undertaking, agreement or instrument evidencing such Indebtedness), (2) is
directly or indirectly liable for any Indebtedness of such Subsidiary or any
Subsidiary of such Subsidiary, or (3) has any obligation to make additional
Investments (other than Permitted Investments) in such Subsidiary or any
Subsidiary of such Subsidiary (other than, with respect to clauses (1) and (2)
above, in the case of any Indebtedness of Iridium or any Restricted Subsidiary,
the proceeds of which were received by Iridium or a Restricted Subsidiary, that
is permitted under Section 4.03 as to which the Unrestricted Subsidiary provides
a Guarantee) and (b) such Subsidiary and each Subsidiary of such Subsidiary has
at least one director on its board of directors that is not a director or
executive officer of Iridium or any Restricted Subsidiary, and (ii) any
Subsidiary of an Unrestricted Subsidiary. The Board of Directors may designate
any Subsidiary to be an Unrestricted Subsidiary by filing a resolution to such
effect with the Trustees unless such Subsidiary or any Subsidiary of such
Subsidiary owns any Capital Stock or Indebtedness of, or owns or holds any Lien
(other than a Permitted Lien) on any property of, Iridium or any other
Subsidiary of Iridium which is not a Subsidiary of the Subsidiary to be so
designated or otherwise an Unrestricted Subsidiary; provided, however, that
either (A) the Subsidiary to be so designated has total assets of $1,000 or less
or (B) immediately after giving effect to such designation, Iridium could incur
an additional $1.00 of Indebtedness pursuant to the first sentence of paragraph
(a) under Section 4.03; and provided further, however, that Iridium could make a
Restricted Payment in an amount equal to the greater of the fair market value
and the book value of such Subsidiary pursuant to Section 4.04 and such amount
is thereafter treated as a Restricted Payment for the purpose of calculating the
aggregate amount available for Restricted Payments thereunder. The Board of
Directors may designate any Unrestricted Subsidiary to be a Restricted
Subsidiary by filing a resolution to such effect with the applicable Trustee,
provided that, immediately after giving effect to such designation, Iridium
could incur an additional $1.00 of Indebtedness pursuant to the first sentence
of paragraph (a) under Section 4.03 and such Subsidiary (as well as each of
Iridium and the other Guarantor Subsidiaries) complies with Section 4.15 as if
such Subsidiary were a newly created Subsidiary. Notwithstanding the foregoing,
neither Capital nor any of its Subsidiaries may be Unrestricted Subsidiaries.

            "Vendor Financing Facility" means any agreements between Iridium
and/or any Subsidiary of Iridium and one or more vendors or lessors of equipment
to Iridium and/or any Subsidiary (or any affiliate of any such vendor or lessor)
providing financing for the acquisition by Iridium or any such Subsidiary of
equipment or services from any such vendor or lessor.

            "Voting Stock" of any Person means Capital Stock of such Person
which ordinarily has voting power for the election of directors (or persons
performing similar functions) of such Person, whether at all times or only so
long as no senior class of securities has such voting power by reason of any
contingency.

            "Wholly-Owned Restricted Subsidiary" means, with respect to Iridium,
a Restricted Subsidiary of Iridium all of the outstanding Capital Stock or other
ownership interests of which (other than Capital Stock constituting directors'
qualifying shares or interests held by directors or shares or interests required
to be held by foreign nationals, in each case to the extent mandated by
applicable law) are owned by Iridium or by one or more Wholly-Owned Restricted
Subsidiaries of Iridium, or by Iridium and one or more Wholly-Owned Restricted
Subsidiaries of Iridium.
   21
                                                                              16


            SECTION 1.02.  Other Definitions.

                                                                      Defined in
            Term                                                        Section
            ----                                                        -------

      "Affiliate Transaction".............................................4.07
      "Agent Members......................................................2.13
      "Bankruptcy Law"....................................................6.01
      "covenant defeasance option".....................................8.01(b)
      "Custodian".........................................................6.01
      "Event of Default"..................................................6.01
      "Global Notes"...................................................2.01(b)
      "Insurance Proceeds"................................................4.16
      "legal defeasance option"........................................8.01(b)
      "Legal Holiday"....................................................11.08
      "Notes".....................................................Introduction
      "Obligations"......................................................10.01
      "Paying Agent"......................................................2.03
      "Registrar".........................................................2.03
      "Restricted Payment"................................................4.04
      "Successor Companies"...............................................5.01
      "Underwriting Agreement.........................................Recitals


            SECTION 1.03.  Incorporation by Reference of Trust Indenture Act.
  This Indenture is subject to the mandatory provisions of the TIA which are
incorporated by reference in and made a part of this Indenture.  The
following TIA terms have the following meanings:

            "Commission" means the SEC.

            "indenture securities" means the Notes.

            "indenture Securityholder" means a Holder.

            "indenture to be qualified" means this Indenture.

            "indenture trustee" or "institutional trustee" means the Trustee.

            "obligor" on the indenture securities means the Issuers and any
other obligor on the indenture securities.

            All other TIA terms used in this Indenture that are defined by the
TIA, defined by TIA reference to another statute or defined by SEC rule have the
meanings assigned to them by such definitions.

            SECTION 1.04.  Rules of Construction.  Unless the context
otherwise requires:

            (1) a term has the meaning assigned to it;

            (2) an accounting term not otherwise defined has the meaning
      assigned to it in accordance with GAAP;

            (3) "or" is not exclusive;

            (4) "including" means including without limitation;

            (5) words in the singular include the plural and words in the plural
      include the singular unless the context otherwise requires;
   22
                                                                              17


            (6) unsecured Indebtedness shall not be deemed to be subordinate or
      junior to Secured Indebtedness of either Note Issuer or a Guarantor
      Subsidiary, as the case may be, merely by virtue of its nature as
      unsecured Indebtedness; and

            (7) the principal amount of any noninterest bearing or other
      discount security at any date shall be the principal amount thereof that
      would be shown on a balance sheet of the issuer dated such date prepared
      in accordance with GAAP and accretion of principal on such security shall
      be deemed to be the Incurrence of Indebtedness.


                                   ARTICLE II

                                    The Notes


            SECTION 2.01. Form and Dating. (a) The Notes and the Trustee's
certificate of authentication thereon shall be substantially in the form of
Exhibit A, which is hereby incorporated in and expressly made a part of this
Indenture, and as otherwise provided in this Article II. The Notes may have
notations, legends or endorsements required by law, stock exchange rule,
agreements to which any Issuer is subject, if any, or usage (provided that any
such notation, legend or endorsement is in a form acceptable to the Note
Issuers). Each Note shall be dated the date of its authentication. The terms of
the Notes set forth in Exhibit A hereto are part of the terms of this Indenture.
The Notes shall be issuable only in registered form without coupons and only in
denominations of $1,000 and any integral multiple of thereof. The Notes are
being offered and sold by the Note Issuers pursuant to the Underwriting
Agreement.

            (b) Notes offered and sold as provided in the Underwriting
Agreement, shall be issued on the Issue Date initially in the form of one or
more permanent global Notes in registered form, substantially in the form set
forth in Exhibit A hereto (the "Global Notes"), deposited with the Trustee, as
custodian for the Depositary, duly executed by the Issuers and authenticated by
the Trustee as hereinafter provided. The aggregate principal amount of any
Global Note may from time to time be increased or decreased by adjustments made
on the records of the Trustee, as custodian for the Depositary or its nominee,
as hereinafter provided.

            SECTION 2.02. Execution and Authentication. An Officer shall sign
the Notes for each of the Note Issuers by manual or facsimile signature. Any
reference herein to the execution of a Note by a Subsidiary Guarantor shall be
interpreted as a reference to the endorsement by such Subsidiary Guarantor of
its Subsidiary Guaranty with respect thereto.

            If an Officer whose signature is on a Note no longer holds that
office at the time the Trustee authenticates such Note, such Note shall be valid
nevertheless.

            A Note shall not be valid until an authorized signatory of the
Trustee manually signs the certificate of authentication on the Note. The
signature shall be conclusive evidence that the Note has been authenticated
under this Indenture.

            The Trustee shall authenticate and deliver Notes for original issue
in an aggregate principal amount of up to $350,000,000 upon the receipt of a
written order of the Note Issuers signed by an Officer of each Note Issuer. Such
order shall specify the amount of the Notes to be authenticated and the date on
which the original issue of Notes is to be authenticated. The aggregate
principal amount of Notes outstanding at any time may not exceed $350,000,000
except as provided in Section 2.07.

            The Trustee may appoint an authenticating agent reasonably
acceptable to Iridium to authenticate the Notes. Any such appointment shall be
evidenced by an instrument signed by an authorized officer of the Trustee, a
copy of which shall be furnished to Iridium. Unless limited by the terms of such
appointment, an authenticating agent may authenticate Notes whenever the Trustee
may do so. Each reference in this Indenture to authentication by the Trustee
includes authentication by such agent. An authenticating agent has the same
rights as any Registrar, Paying Agent or agent for service of notices and
demands.
   23
                                                                              18


            Upon execution and delivery of the Indenture, the Notes shall be
endorsed by each of the Initial Guarantors to evidence their Guaranties of the
obligations thereunder.

            The Issuers, the Trustee and any agent of the Issuers or the Trustee
may treat the person in whose name any Note is registered as the owner of such
Note for the purpose of receiving payment of principal of and (subject to the
provisions of this Indenture and the Notes with respect to record dates)
interest on such Note and for all other purposes whatsoever, whether or not such
Note is overdue, and neither the Issuers, the Trustee nor any agent of the
Issuers or the Trustee shall be affected by notice to the contrary.

            SECTION 2.03. Registrar and Paying Agent. The Note Issuers shall
maintain an office or agency in the Borough of Manhattan, City of New York where
Notes may be presented for registration of transfer or for exchange (the
"Registrar") and an office or agency where Notes may be presented for payment
(the "Paying Agent"). The Registrar shall keep a register of the Notes and of
their transfer and exchange. The Note Issuers may have one or more co-registrars
and one or more additional paying agents. The term "Paying Agent" includes any
additional paying agent.

            The Note Issuers shall enter into an appropriate agency agreement
with any Registrar, Paying Agent or co-registrar not a party to this Indenture,
which shall incorporate the applicable terms of the TIA. The agreement shall
implement the provisions of this Indenture that relate to such agent. The Note
Issuers shall notify the Trustee in writing of the name and address of any such
agent. If the Note Issuers fail to maintain a Registrar or Paying Agent, the
Trustee shall act as such and shall be entitled to appropriate compensation and
indemnity therefor pursuant to Section 7.07. The Note Issuers or any of their
domestically incorporated Wholly-Owned Restricted Subsidiaries may act as Paying
Agent, Registrar, co-registrar or transfer agent.

            The Note Issuers initially appoint the Trustee as Registrar and
Paying Agent in connection with the Notes. The office of the Registrar and
Paying Agent for purposes of this Section 2.03 shall be at 61 Broadway, 15th
Floor, New York, New York 10006.

            The Note Issuers initially appoint The Depository Trust Company to
act as Depositary with respect to the Global Notes.

            Iridium may remove any Registrar or Paying Agent upon written notice
to such Registrar or Paying Agent and to the Trustee; provided that no such
removal shall become effective until (1) acceptance of an appointment by a
successor as evidenced by an appropriate agreement entered into by the Note
Issuers and such successor Registrar or Paying Agent, as the case may be, and
delivered to the Trustee or (2) notification to the Trustee that the Trustee
shall serve as Registrar or Paying Agent until the appointment of a successor in
accordance with clause (1) above. The Registrar or Paying Agent may resign at
any time upon written notice; provided, however, that the Trustee may resign as
Paying Agent or Registrar only if the Trustee also resigns as Trustee in
accordance with Section 7.08.

            SECTION 2.04. Paying Agent To Hold Money in Trust. Prior to each due
date of the principal and interest on any Note, the Note Issuers shall deposit
with the Paying Agent (or if a Note Issuer or a domestically organized
Wholly-Owned Restricted Subsidiary is acting as Paying Agent, segregate and hold
in trust for the benefit of the Persons entitled thereto) a sum sufficient to
pay such principal and interest when so becoming due. The Note Issuers shall
require each Paying Agent (other than the Trustee) to agree in writing that the
Paying Agent shall hold in trust for the benefit of Holders or the Trustee all
money held by the Paying Agent for the payment of principal of or interest on
the Notes and shall notify the Trustee of any default by the Note Issuers in
making any such payment, if a Note Issuer or a domestically organized
Wholly-Owned Restricted Subsidiary acts as Paying Agent, it shall segregate the
money held by it as Paying Agent and hold it as a separate trust fund. The Note
Issuers at any time may require a Paying Agent to pay all money held by it to
the Trustee and to account for any funds disbursed by the Paying Agent. Upon
complying with this Section, the Paying Agent shall have no further liability
for the money delivered to the Trustee.

            Any money deposited with any Paying Agent, or then held by a Note
Issuer or a domestically organized Wholly-Owned Restricted Subsidiary in trust
for the payment of principal or interest on any Note and remaining unclaimed for
two years after such principal and interest has become due and payable shall,
subject to the requirements of applicable escheat laws, be paid to Iridium at
its request, or, if then held by a Note Issuer or such a Subsidiary, shall be
discharged from such trust; and the Holders shall thereafter, as unsecured
general creditors, look 
   24
                                                                              19


only to the Note Issuers for payment thereof, and all liability of the Paying
Agent with respect to such money shall thereupon cease.

            SECTION 2.05. Holder Lists. The Trustee shall preserve in as current
a form as is reasonably practicable the most recent list available to it of the
names and addresses of Holders. If the Trustee is not the Registrar, Iridium
shall furnish, or cause the Registrar to furnish, to the Trustee, in writing at
least five Business Days before each interest payment date and at such other
times as the Trustee may request in writing, a list in such form and as of such
date as the Trustee may reasonably require of the names and addresses of
Holders.

            SECTION 2.06. Transfer and Exchange. The Notes shall be issued in
registered form and shall be transferable only upon the surrender of a Note for
registration of transfer. When a Note is presented to the Registrar or a
co-registrar with a request to register a transfer, the Registrar shall register
the transfer as requested if the requirements of Section 8-401(l) of the Uniform
Commercial Code are met, as stated to the Registrar in an opinion of counsel if
requested by the Registrar. When Notes are presented to the Registrar or a
co-registrar with a request to exchange them for an equal principal amount of
Notes of other denominations, the Registrar shall make the exchange as requested
if the same requirements are met. To permit registration of transfers and
exchanges, the Issuers shall execute and the Trustee shall authenticate Notes at
the Registrar's or co-registrar's request. The Note Issuers may require payment
of a sum sufficient to pay all taxes, assessments or other governmental charges
in connection with any transfer or exchange pursuant to this Section. The Note
Issuers shall not be required to make and the Registrar need not register
transfers or exchanges of Notes selected for redemption (except, in the case of
Notes to be redeemed in part, the portion thereof not to be redeemed) or any
Notes for a period of 15 days before a selection of Notes to be redeemed or 15
days before an Interest Payment Date.

            Prior to the due presentation for registration of transfer of any
Note, the Issuers, the Trustee, the Paying Agent, the Registrar or any
co-registrar may deem and treat the Person in whose name a Note is registered as
the absolute owner of such Note for the purpose of receiving payment of
principal of and interest, if any, on such Note and for all other purposes
whatsoever, whether or not such Note is overdue, and none of the Issuers, the
Trustee, the Paying Agent, the Registrar or any co-registrar shall be affected
by notice to the contrary.

            Any Holder of a Global Note shall, by acceptance of such Global
Note, agree that transfers of beneficial interest in such Global Note may be
effected only through a book-entry system maintained by the Holder of such
Global Note (or its agent), and that ownership of a beneficial interest in such
Global Note shall be required to be reflected in a book entry.

            All Notes issued upon any transfer or exchange pursuant to this
Section 2.06 shall evidence the same debt and shall be entitled to the same
benefits under this Indenture as the Notes surrendered upon such transfer or
exchange.

            SECTION 2.07. Replacement Notes. If a mutilated Note is surrendered
to the Registrar or if the Holder of a Note claims that the Note has been lost,
destroyed or wrongfully taken, the Note Issuers shall issue, the Guarantor
Subsidiaries shall execute and the Trustee shall authenticate a replacement Note
if the requirements of Section 8-405 of the Uniform Commercial Code are met,
such that the Holder (i) satisfies Iridium or the Trustee within a reasonable
time after he has notice of such loss, destruction or wrongful taking and the
Registrar does not register a transfer prior to receiving such notification that
such requirements are met, (ii) makes such request to Iridium or the Trustee
prior to the Note being acquired by a bona fide purchaser and (iii) satisfies
any other reasonable requirements of the Trustee including, if requested, an
opinion of counsel for the Holder to the effect that the Holder has complied
with the requirements of this Section 2.07. If required by the Trustee or
Iridium, such Holder shall furnish an indemnity bond sufficient in the judgment
of the Trustee or Iridium, as the case may be, to protect the Issuers, the
Trustee, the Paying Agent, the Registrar and any co-registrar from any loss that
any of them may suffer if a Note is replaced. Iridium and the Trustee may charge
the Holder for their expenses in replacing a Note. In the event any such
mutilated, lost, destroyed or wrongfully taken Note has become or is about to
become due and payable, the Issuers in its discretion may pay such Note instead
of issuing a new Note in replacement thereof.

            Every replacement Note is an additional obligation of the Issuers.
   25
                                                                              20


            The provisions of this Section 2.07 are exclusive and shall preclude
(to the extent lawful) all other rights and remedies with respect to the
replacement or payment of mutilated, lost, destroyed or wrongfully taken Notes.

            SECTION 2.08. Outstanding Notes. Notes outstanding at any time are
all senior Notes authenticated by the Trustee except for those canceled by it,
those delivered to it for cancellation and those described in this Section as
not outstanding. A Note does not cease to be outstanding because an Issuer or an
Affiliate of an Issuer holds the Note.

            If a Note is replaced pursuant to Section 2.07, it ceases to be
outstanding unless the Trustee and Iridium receive proof satisfactory to them
that the replaced Note is held by a bona fide purchaser.

            If the Paying Agent segregates and holds in trust, in accordance
with this Indenture, on a redemption date or maturity date money sufficient to
pay all principal and interest payable on that date with respect to the Notes
(or portions thereof) to be redeemed or maturing, as the case may be, and the
Paying Agent is not prohibited from paying such money to the Holders on that
date pursuant to the terms of this Indenture, then on and after that date such
Notes (or portions thereof) cease to be outstanding and interest on them ceases
to accrue.

            In determining whether the Holders of the required principal amount
of Notes have concurred in any direction, waiver or consent, Notes owned by the
Issuers or any of its Affiliates shall be disregarded, except that, for the
purposes of determining whether the Trustee shall be protected in relying on any
such direction, waiver or consent, only Notes which the Trustee knows or has
reason to know are so owned shall be disregarded.

            SECTION 2.09. Temporary Notes. Until Definitive Notes and Global
Notes are ready for delivery, the Issuers may prepare and the Trustee shall
authenticate temporary Notes. Temporary Notes shall be substantially in the form
of Definitive Notes but may have variations that Iridium considers appropriate
for temporary Notes. Without unreasonable delay, the Issuers shall prepare and
the Trustee shall authenticate Definitive Notes and deliver them in exchange for
temporary Notes upon surrender of such temporary Notes at the office or agency
of the Note Issuers, without charge to the Holder.

            SECTION 2.10. Cancellation. A Note Issuer at any time may deliver
Notes to the Trustee for cancellation. The Registrar and the Paying Agent shall
forward to the Trustee any Notes surrendered to them for registration of
transfer, exchange or payment. The Trustee and no one else shall cancel and
destroy (subject to the record retention requirements of the Exchange Act) all
Notes surrendered for registration of transfer, exchange, payment or
cancellation unless Iridium directs the Trustee to deliver canceled Notes to
Iridium. The Issuers may not issue new Notes to replace Notes they have
redeemed, paid or delivered to the Trustee for cancellation. The Trustee shall
not authenticate Notes in place of canceled Notes other than pursuant to the
terms of this Indenture.

            SECTION 2.11. Defaulted Interest. If the Issuers default in a
payment of interest on the Notes, the Issuer shall pay the defaulted interest
(plus interest on such defaulted interest to the extent lawful) in any lawful
manner. The Issuers may pay the defaulted interest to the persons who are
Holders on a subsequent special record date. The Note Issuers shall fix or cause
to be fixed any such special record date and payment date to the reasonable
satisfaction of the Trustee and shall promptly mail or cause to be mailed to
each Holder a notice that states the special record date, the payment date and
the amount of defaulted interest to be paid.

            The Issuers may make payment of any defaulted interest in any other
lawful manner not inconsistent with the requirements (if applicable) of any
securities exchange on which the Notes may be listed, and upon such notice as
may be required by such exchange, if, after notice given by the Note Issuers to
the Trustee of the proposed payment pursuant to this paragraph, such manner of
payment shall be deemed practicable by the Trustee.

            SECTION 2.12. CUSIP Numbers. The Note Issuers in issuing the Notes
may use "CUSIP" numbers (if then generally in use) and, if so, the Trustee shall
use "CUSIP" numbers in notices of redemption as a convenience to Holders;
provided, however, that any such notice may state that no representation is made
as to the correctness of such numbers either as printed on the Notes or as
contained in any notice of a redemption and that reliance may be placed only on
the other identification numbers printed on the Notes, and any such redemption
shall not be affected by any defect in or omission of such numbers.
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                                                                              21


            SECTION 2.13. Book-Entry Provisions for Global Notes.

            (a) Each Global Note initially shall (i) be registered in the name
of the Depositary for such Global Note or the nominee of such Depositary and
(ii) be delivered to the Trustee as custodian for such Depositary and (iii) bear
the Global Securities legend as set forth in Exhibit A hereto.

            Members of, or participants in, the Depositary ("Agent Members")
shall have no rights under this Indenture with respect to any Global Note held
on their behalf by the Depositary, or the Trustee as its custodian, or under
such Global Note, and the Depositary may be treated by the Issuers, the Trustee
and any agent of the Issuers or the Trustee as the absolute owner of such Global
Note for all purposes whatsoever. Notwithstanding the foregoing, nothing herein
shall prevent the Issuers, the Trustee or any agent of the Issuers or the
Trustee from giving effect to any written certification, proxy or other
authorization furnished by the Depositary or shall impair, as between the
Depositary and its Agent Members, the operation of customary practices governing
the exercise of the rights of a Holder of any Note.

            (b) Transfers of a Global Note shall be limited to transfers of such
Global Note in whole, but not in part, to the Depositary, its successors or
their respective nominees. Interests of beneficial owners in a Global Note may
be transferred in accordance with the rules and procedures of the Depositary.
Beneficial owners of interests in a Global Note may obtain Definitive Notes in
exchange for their beneficial interests in a Global Note only if (i) the Note
Issuers notify the Trustee in writing that the Depositary is no longer willing
or able to act as Depositary for such Global Note or the Depositary ceases to be
a "clearing agency" registered under the Exchange Act, at a time when the
Depositary is required to be so registered in order to act as Depositary, and,
in each case, a successor depositary is not appointed by the Note Issuers within
90 days of such notice, (ii) the Note Issuers, at their option, notify the
Trustee in writing that they elect to cause the issuance of Definitive Notes or
(iii) an Event of Default has occurred and is continuing and the Registrar has
received a request from the Depositary to effect such exchange.

            (c) In connection with any transfer of a portion of the beneficial
interest in a Global Note pursuant to Section 2.13(b), the Registrar shall
reflect on its books and records the date and a decrease in the principal amount
of such Global Note in an amount equal to the principal amount of the beneficial
interest in the Global Note to be transferred, and the Issuers shall execute,
and the Trustee shall authenticate and deliver, one or more Definitive Notes of
like tenor and amount.

            (d) Any beneficial interest in one of the Global Notes that is
transferred to a person who takes delivery in the form of an interest in the
other corresponding Global Note will, upon transfer, cease to be an interest in
such Note and become an interest in the other corresponding Note and,
accordingly, will thereafter be subject to all transfer restrictions, if any,
and other procedures applicable to beneficial interest in such other
corresponding Note for as long as it remains such an interest.

            (e) In connection with the transfer of an entire Global Note to
beneficial owners pursuant to subsection (b) of this Section 2.13, such Global
Note shall be deemed to be surrendered to the Trustee for cancellation, and the
Issuers shall execute, and the Trustee shall authenticate and deliver, to each
beneficial owner identified by the Depositary in exchange for its beneficial
interest in such Global Note, an equal aggregate principal amount of Definitive
Notes of authorized denominations.

            (f) The registered holder of a Global Note may grant proxies and
otherwise authorize any person, including Agent Members and persons that may
hold interests through Agent Members, to take any action which a Holder is
entitled to take under this Indenture or the Notes.

            (g) The Registrar shall retain copies of all letters, notices and
other written communications received pursuant to this Section 2.13. The Issuers
shall have the right to inspect and make copies of all such letters, notices or
other written communications at any reasonable time upon the giving of
reasonable written notice to the Registrar.
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                                                                              22


                                  ARTICLE III

                                   Redemption


            SECTION 3.01. Notices to Trustee. If either Note Issuer elects to
redeem Notes pursuant to Section 3.07, it shall notify the Trustee in writing of
the redemption date and the principal amount of Notes to be redeemed.

            The Note Issuer shall give each notice to the Trustee provided for
in this Section 3.01 at least 30 days before the redemption date unless the
Trustee consents to a shorter period. Such notice shall be accompanied by an
Officers' Certificate from the Note Issuer to the effect that such redemption
shall comply with the conditions herein. If fewer than all the Notes are to be
redeemed, the record date relating to such redemption shall be selected by
Iridium and given to the Trustee, which record date shall be not less than 15
days after the date of notice to the Trustee (unless a shorter period shall be
acceptable to the Trustee). Any such notice may be canceled by notice in writing
to the Trustee at any time prior to notice of such redemption being mailed to
any Holder and shall thereby be void and of no effect.

            SECTION 3.02. Selection of Securities to be Redeemed. If fewer than
all the Notes are to be redeemed, the Trustee shall select the Notes to be
redeemed pro rata or by lot or by such other method as the Trustee in its sole
discretion deems to be fair and appropriate. The Trustee shall make the
selection from outstanding Notes not previously called for redemption. The
Trustee may select for redemption portions of the principal of Notes that have
denominations larger than $1,000. Securities and portions of them the Trustee
selects shall be in amounts of $1,000 or a whole multiple of $1,000. Provisions
of this Indenture that apply to Notes called for redemption also apply to
portions of Notes called for redemption. The Trustee shall notify the Note
Issuers promptly of the Notes or portions of Notes to be redeemed.

            SECTION 3.03. Notice of Redemption. Any notice of redemption shall
identify the Notes to be redeemed and shall state:

            (1) the redemption date;

            (2) the redemption price;

            (3) the name and address of the Paying Agent;

            (4) that Notes called for redemption must be surrendered to the
      Paying Agent to collect the redemption price;

            (5) if fewer than all the outstanding Notes are to be redeemed, the
      certificate numbers and principal amounts of the particular Notes to be
      redeemed;

            (6) that, unless the Note Issuers default in making such redemption
      payment or the Paying Agent is prohibited from making such payment
      pursuant to the terms of this Indenture, interest on Notes (or portion
      thereof) called for redemption ceases to accrue on and after the
      redemption date;

            (7) the CUSIP number, if any, printed on the Notes being redeemed;

            (8) that no representation is made as to the correctness or accuracy
      of the CUSIP number, if any, listed in such notice or printed on the
      Notes; and

            (9) that if a Note is to be redeemed in part, only the portion of
      the principal amount (equal to $1,000 or an integral multiple thereof) of
      such Note to be redeemed and that a new Note in the aggregate principal
      amount equal to the unredeemed portion thereof shall be issued without
      charge to the holder.

            At either Note Issuer's request (which may be revoked at any time in
writing prior to the time at which the Trustee shall have given such notice to
the Holders), the Trustee shall give the notice of redemption in the 
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                                                                              23


applicable Note Issuer's name and at the Note Issuer's expense. In such event,
the Note Issuer shall provide the Trustee with the information required by this
Section 3.03.

            SECTION 3.04. Effect of Notice of Redemption. Once notice of
redemption is mailed, Notes called for redemption become due and payable on the
redemption date and at the redemption price stated in the notice. Upon surrender
to the Paying Agent, such Notes shall be paid at the redemption price stated in
the notice, plus accrued interest, if any, to the redemption date; provided that
if the redemption date is after a regular record date and on or prior to the
interest payment date, the accrued interest shall be payable to the Holder of
the redeemed Notes registered on the relevant record date. If mailed in the
manner provided herein, the notice shall be conclusively presumed to have been
given whether or not the Holder receives such notice. Failure to give notice or
any defect in the notice to any Holder shall not affect the validity of the
notice to any other Holder.

            SECTION 3.05. Deposit of Redemption Price. At least one Business Day
prior to the redemption date, the applicable Note Issuer shall deposit with the
Paying Agent (or, if a Note Issuer or a Subsidiary is the Paying Agent, shall
segregate and hold in trust) money sufficient to pay the redemption price of and
accrued interest on all Notes to be redeemed on that date other than Notes or
portions of Notes called for redemption which have been delivered by such Note
Issuer to the Trustee for cancellation.

            SECTION 3.06. Notes Redeemed in Part. Upon surrender of a Note that
is redeemed in part, the Issuers shall execute and the Trustee shall
authenticate for the Holder (at the Note Issuers' expense) a new Note equal in
principal amount to the unredeemed portion of the Note surrendered.

            SECTION 3.07. Optional Redemption. (a) Except as set forth in
Section 3.07(b), the Notes may not be redeemed prior to July 15, 2002. On and
after that date, either Note Issuer may redeem the Notes in whole or in part at
the following redemption prices (expressed in percentages of principal amount),
plus accrued and unpaid interest to the redemption date (subject to the right of
Holders of record on the relevant record date to receive interest due on the
relevant interest payment date that is on or prior to the date of redemption),
if redeemed during the 12-month period commencing on July 15 of the years set
forth below:

                                                        Redemption
Period                                                     Price
- ------                                                     -----

2002...................................................   ______%
2003...................................................   ______%
2004 and thereafter....................................  100.000%

            (b) In addition, at any time on or prior to July 15, 2000, either
Note Issuer may redeem in the aggregate up to 33-1/3% of the original aggregate
principal amount of Notes with the proceeds of one or more Equity Offerings at a
redemption price (expressed as a percentage of principal amount thereof) of
______% plus accrued and unpaid interest to the redemption date (subject to the
right of Holders of record on the relevant record date to receive interest due
on the relevant interest payment date that is on or prior to the date of
redemption); provided, however, that at least 66-2/3% of the original aggregate
principal amount of the Notes being redeemed must remain outstanding after each
such redemption.


                                   ARTICLE IV

                                    Covenants


            SECTION 4.01. Payment of Notes. The Note Issuers, as joint and
several obligors, shall promptly pay the principal of and interest on the Notes
on the dates and in the manner provided in the Notes and in this Indenture.
Principal and interest shall be considered paid on the date due if on such date
the Trustee or the Paying Agent holds in accordance with this Indenture money
sufficient to timely pay all principal and interest then due and the Trustee or
the Paying Agent, as the case may be, is not prohibited from paying such money
to the Holders on that date pursuant to the terms of this Indenture.
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                                                                              24


            The Note Issuers, as joint and several obligors, shall pay interest
on overdue principal at the rate specified therefor in the Notes, and shall pay
interest on overdue installments of interest at the same rate to the extent
lawful.

            SECTION 4.02. SEC Reports. Notwithstanding that Iridium may not be
required to be or remain subject to the reporting requirements of Section 13 or
15(d) of the Exchange Act, Iridium shall file with the SEC, and provide the
Trustees and Holders and prospective Holders (upon request) with the annual
reports and the information, documents and other reports which are specified in
Sections 13 and 15(d) of the Exchange Act.

            The foregoing shall not require Capital or any Guarantor Subsidiary
to file, provide or furnish with or to any Person any report or information
separate from any report or information filed, provided or furnished by Iridium
to the extent Capital or any Guarantor Subsidiary would not be required to do so
under Section 13 or 15(d) of the Exchange Act.

            SECTION 4.03. Limitation on Indebtedness.

            (a) Iridium shall not, and shall not permit any Restricted
Subsidiary to, Incur any Indebtedness (including any Acquired Indebtedness)
unless (i) immediately after giving effect to the Incurrence of such
Indebtedness and the receipt and application of the proceeds thereof, the Debt
to Cash Flow Ratio would be less than 4.0 to 1.0 and (ii) if such Indebtedness
is Incurred by a Restricted Subsidiary, such Restricted Subsidiary is a
Guarantor Subsidiary. Notwithstanding the foregoing, prior to June 30, 2000,
Iridium, Capital and any other Restricted Subsidiary that is a Guarantor
Subsidiary may Incur Indebtedness if immediately after giving effect to the
Incurrence of such Indebtedness and the receipt and application of the proceeds
thereof, the Debt to Capital Ratio would be less than 65%.

            (b) Notwithstanding the foregoing paragraph (a), Iridium, Capital
and any other Restricted Subsidiary that is a Guarantor Subsidiary may Incur the
following Indebtedness:

                  (i) Indebtedness Incurred under any one or more Bank Credit
      Agreements, Vendor Financing Facilities or other agreements or
      arrangements to finance the Build-out of the IRIDIUM System; provided,
      however, that Indebtedness Incurred pursuant to this clause (i), other
      than Indebtedness Incurred pursuant to a Bank Credit Agreement or Vendor
      Financing Facility, shall not have a Stated Maturity earlier than the
      Stated Maturity of the Notes, and shall not be mandatorily redeemable,
      pursuant to a sinking fund obligation or otherwise, or be redeemable at
      the option of the holder thereof, in whole or in part, prior to the Stated
      Maturity of the Notes (other than pursuant to provisions which are
      substantially similar to those contained in Section 4.08 which permit the
      holders of such Indebtedness to require the issuer thereof to repurchase
      or repay such Indebtedness upon a Change of Control (or an event
      substantially similar thereto) or to make an offer to purchase as a result
      of the occurrence of an Asset Disposition (or an event substantially
      similar thereto) or receipt of insurance proceeds);

                  (ii) After Commercial Activation, Indebtedness under any one
      or more Bank Credit Agreements or other agreements or arrangements to
      finance working capital requirements of Iridium and any Refinancing
      Indebtedness in respect of such Indebtedness; provided, however, at the
      time of the Incurrence of such Indebtedness and after giving effect
      thereto, the aggregate principal amount of all Indebtedness Incurred
      pursuant to this clause (ii) and then outstanding does not exceed
      $950,000,000;

                  (iii) Indebtedness Incurred under any one or more Bank Credit
      Agreements, Vendor Financing Facilities or other agreements or
      arrangements that is guaranteed pursuant to the Motorola Additional
      Guarantee; provided, however, at the time of Incurrence of such
      Indebtedness and after giving effect thereto, the aggregate principal
      amount of all Indebtedness incurred pursuant to this clause (iii) and then
      outstanding does not exceed $350,000,000;

                  (iv) Indebtedness owed by Iridium to Capital or any
      Wholly-Owned Restricted Subsidiary that is a Guarantor Subsidiary or
      Indebtedness owed by Capital or any Wholly-Owned Restricted Subsidiary
      that is a Guarantor Subsidiary to Iridium or to Capital or another
      Wholly-Owned Restricted Subsidiary that is a Guarantor Subsidiary;
      provided, however, that upon either (x) the transfer or other disposition
      by Capital, such Wholly-Owned Restricted Subsidiary or Iridium of any
      Indebtedness so permitted to a Person other than Iridium, Capital or
      another Wholly-Owned Restricted Subsidiary that is a 
   30
                                                                              25


      Guarantor Subsidiary or (y) the issuance, sale, lease, transfer or other
      disposition of shares of Capital Stock (including by consolidation or
      merger, but not including directors' qualifying shares or interests
      required to be held by foreign nationals, in each case to the extent
      mandated by applicable law) of such Wholly-Owned Restricted Subsidiary or
      Capital to a Person other than Iridium, Capital or another such
      Wholly-Owned Restricted Subsidiary, the provisions of this clause (iv)
      shall no longer be applicable to such Indebtedness and such Indebtedness
      shall be deemed to have been Incurred by the issuer thereof at the time of
      such issuance, sale, lease, transfer or other disposition;

                  (v) Refinancing Indebtedness Incurred to Refinance
      Indebtedness Incurred pursuant to Section 4.03(a) or pursuant to clause
      (i), (ii), (iii), (vii) or (viii) or this clause (v) of this Section
      4.03(b);

                  (vi) Indebtedness consisting of Permitted Interest Rate or
      Currency Protection Agreements;

                  (vii) Indebtedness represented or evidenced by the Notes and
      the Subsidiary Guaranties;

                  (viii) Indebtedness outstanding on the Issue Date (other than
      the Guaranteed Bank Facility and other Indebtedness described in clause
      (i), (ii), (iii), (iv) or (vii) of this Section 4.03(b));

                  (ix) Indebtedness consisting of performance and other similar
      bonds and reimbursement obligations Incurred in the ordinary course of
      business securing the performance of contractual, franchise or license
      obligations of Iridium, Capital or a Restricted Subsidiary, or in respect
      of a letter of credit obtained to secure such performance; and

                  (x) Indebtedness in an aggregate principal amount which,
      together with all other Indebtedness of Iridium, Capital and other
      Restricted Subsidiaries that are Guarantor Subsidiaries outstanding on the
      date of such Incurrence (without duplication and other than Indebtedness
      permitted by clauses (i) through (ix) above or Section 4.03(a)) does not
      exceed $100,000,000.

            (c) For purposes of determining compliance with this covenant, in
the event that an item of Indebtedness meets the criteria of more than one of
the types of Indebtedness, Iridium, Capital and the other Restricted
Subsidiaries are permitted to Incur, Iridium, Capital or such Restricted
Subsidiary, as the case may be, shall have the right, in Iridium's sole
discretion, to classify such item of Indebtedness at the time of its Incurrence
and shall only be required to include the amount and type of such Indebtedness
under the clause permitting the Indebtedness as so classified.

            SECTION 4.04. Limitation on Restricted Payments.

            (a) Iridium shall not, and shall not permit any Restricted
Subsidiary, directly or indirectly, to:

                  (i) declare or pay any dividend or make any distribution on or
      in respect of its Capital Stock (including any payment in connection with
      any merger or consolidation involving the Note Issuers), except dividends
      or distributions payable solely in its Capital Stock (other than
      Disqualified Stock) and cash to the extent required to pay for fractional
      shares of such Capital Stock or payable to Iridium or another Restricted
      Subsidiary (and, if such Restricted Subsidiary has shareholders other than
      the Note Issuers or other Restricted Subsidiaries, to its other
      shareholders on a pro rata basis or on a basis that results in the receipt
      by the Note Issuers or a Restricted Subsidiary of dividends or
      distributions of equal or greater value);

                  (ii) purchase, redeem, retire or otherwise acquire for value
      any Capital Stock of Iridium or any Restricted Subsidiary held by Persons
      other than Iridium or another Restricted Subsidiary;

                  (iii) purchase, repurchase, redeem, defease, acquire or retire
      for value, or otherwise make any principal payment on, any Subordinated
      Obligations prior to the scheduled maturity, scheduled repayment or
      scheduled sinking fund payment thereof (other than the purchase,
      repurchase or other acquisition of Subordinated Obligations purchased in
      anticipation of satisfying a sinking fund obligation, principal
      installment or final maturity, in each case due within one year of the
      date of acquisition, or any 
   31
                                                                              26


      purchase, repurchase, redemption or other acquisition or prepayment
      thereof in connection with any Refinancing thereof permitted pursuant to
      clause (v) of paragraph (b) of Section 4.03); or

                  (iv) make any Investment (other than a Permitted Investment)
      in any Person (any such dividend, distribution, purchase, redemption,
      repurchase, defeasance, other acquisition, retirement, Investment or
      payment being herein referred to as a "Restricted Payment"), if at the
      time Iridium or such Restricted Subsidiary makes such Restricted Payment:
      (1) a Default has occurred and is continuing (or would result therefrom);
      (2) Iridium could not Incur at least $1.00 of additional Indebtedness
      pursuant to the terms of the first sentence of paragraph (a) of Section
      4.03; or (3) the aggregate amount of such Restricted Payment and all other
      Restricted Payments declared or made subsequent to the Issue Date would
      exceed the sum of:

                        (A) 50% of the Consolidated Net Income of Iridium
            accrued during the period (treated as one accounting period) from
            the beginning of the fiscal quarter immediately following the fiscal
            quarter during which July 16, 1997 occurs to the end of the most
            recent fiscal quarter for which internal financial statements are
            available at the time of such Restricted Payment (or, in case such
            Consolidated Net Income is a deficit, minus 100% of such deficit);
            provided, however, that the aggregate amount calculated pursuant to
            this clause (A) (if such aggregate amount is a negative amount)
            shall be reset to zero on the first date on which the Notes are
            assigned an Investment Grade Rating by both Rating Agencies;

                        (B) the aggregate Net Cash Proceeds received by Iridium
            from the issuance or sale of its Capital Stock (other than
            Disqualified Stock) subsequent to the Issue Date (other than an
            issuance or sale to a Restricted Subsidiary and other than an
            issuance or sale to an employee stock ownership plan or to a trust
            established by Iridium or any Restricted Subsidiaries for the
            benefit of their employees);

                        (C) the amount by which Indebtedness of Iridium is
            reduced on the balance sheet of Iridium upon the conversion or
            exchange (other than by a Restricted Subsidiary) subsequent to the
            Issue Date of any Indebtedness of Iridium convertible or
            exchangeable for Capital Stock (other than Disqualified Stock) of
            Iridium (less the amount of any cash, or the fair value of any other
            property or assets of Iridium or any Restricted Subsidiary,
            distributed by Iridium upon such conversion or exchange); and

                        (D) an amount equal to the sum of (i) the net reduction
            in Investments in Unrestricted Subsidiaries resulting from
            dividends, repayments of loans or advances or other transfers of
            assets, in each case to Iridium or any Restricted Subsidiary from
            Unrestricted Subsidiaries, and (ii) the portion (proportionate to
            Iridium's equity interest in such Subsidiary) of the fair market
            value of the net assets of an Unrestricted Subsidiary (as evidenced
            by a resolution of the Board of Directors in the manner set forth in
            Section 4.04(c)) at the time such Unrestricted Subsidiary is
            designated a Restricted Subsidiary; provided, however, that the
            foregoing sum does not exceed, in the case of any Unrestricted
            Subsidiary, the amount of Investments previously made (and treated
            as a Restricted Payment) by Iridium or any Restricted Subsidiary in
            such Unrestricted Subsidiary.

      (b) Notwithstanding the foregoing, Iridium may:

            (i) subject to clause (vii) below, pay any dividend on Capital Stock
      of any class within 60 days after the declaration thereof if, on the date
      when the dividend was declared, Iridium could have paid such dividend in
      accordance with the foregoing provisions;

            (ii) repurchase any Capital Stock from Persons who were formerly
      officers, managers or employees of Iridium LLC or any of its Subsidiaries
      (or from IWCL in connection with or relating to a repurchase by IWCL of
      its Capital Stock from such Persons); provided, however, that the
      aggregate amount of all such repurchases made pursuant to this clause (ii)
      shall not exceed $2,000,000, plus the aggregate cash proceeds received by
      Iridium since July 16, 1997 from the issuance of its Capital Stock to
      officers, managers and employees of Iridium or any of its Subsidiaries (or
      from IWCL in connection with or relating to such an issuance by IWCL to
      such Persons);
   32
                                                                              27


            (iii) Refinance, and permit its Restricted Subsidiaries to
      Refinance, any Indebtedness otherwise permitted to be Refinanced by clause
      (v) of paragraph (b) under Section 4.03.

            (iv) during the period any of Iridium or Iridium LLC is treated as a
      partnership for U.S. federal income tax purposes and after such period to
      the extent relating to the liability for such period, make distributions
      in respect of members' or partners' income tax liability with respect to
      Iridium or Iridium LLC in an amount not to exceed the Tax Amount;

            (v) make distributions to Iridium LLC to pay Iridium LLC's or IWCL's
      ordinary and reasonable operating expenses related to Iridium LLC, as set
      forth in an Officers' Certificate delivered to the Trustee;

            (vi) repurchase any Capital Stock pursuant to Section 11.03 of the
      LLC Agreement in the event a member of Iridium fails to pay any of the
      amounts required by a Reserve Capital Call;

            (vii) make any Restricted Payment by exchange for, or out of the
      proceeds of the substantially concurrent sale of, or capital contribution
      in respect of, Capital Stock of Iridium (other than Disqualified Stock and
      other than Capital Stock issued or sold to a Subsidiary of Iridium or an
      employee stock ownership plan or to a trust established by Iridium or any
      of its Subsidiaries for the benefit of their employees);

            (viii) make any Restricted Payment pursuant to the Interest Exchange
      Agreement, the Share Issuance Agreement, the Master Subscription Agreement
      or the Management Services Agreement; and

            (ix) make other Restricted Payments in an aggregate amount not to
      exceed $10,000,000.

      Any Restricted Payment made pursuant to clauses (ii), (iii), (iv), (vii),
(viii) and (ix) of the immediately preceding paragraph shall be excluded from
the calculation of the aggregate amount of Restricted Payments made since the
Issue Date; provided, however, that the Net Cash Proceeds from the issuance of
Capital Stock pursuant to clauses (ii) and (vii) of the immediately preceding
paragraph shall be excluded from the calculation of amounts under clause (B) of
the second preceding paragraph. A dividend or distribution by a Restricted
Subsidiary in respect of its Capital Stock shall only be deemed to be a
Restricted Payment to the extent such dividend or distribution is paid to
entities other than Iridium and the Restricted Subsidiaries.

      (c) The net proceeds from the issuance of shares of Capital Stock upon
conversion of Indebtedness shall be deemed to be an amount equal to (i) the
accreted value of such Indebtedness on the date of such conversion and (ii) the
additional consideration, if any, received by Iridium upon such conversion
thereof, less any cash payment on account of fractional shares. The amount of
all Restricted Payments (other than cash) shall be the fair market value
(evidenced by a resolution of the Board of Directors determined in good faith
and set forth in an Officers' Certificate delivered to the Trustee) on the date
of the Restricted Payment of the asset(s) proposed to be transferred by Iridium
or such Restricted Subsidiary, as the case may be, pursuant to the Restricted
Payment. Not later than the date of making any Restricted Payment, Iridium shall
deliver to the Trustee an Officers' Certificate identifying each Restricted
Payment made by Iridium during such fiscal quarter and stating that such
Restricted Payment is permitted and setting forth the basis upon which the
calculations required by this Section 4.04 were computed, which calculations may
be based upon Iridium's latest available financial statements. If Iridium makes
a Restricted Payment which, at the time of the making of such Restricted
Payment, would in the good faith determination of Iridium be permitted under
this Indenture, such Restricted Payment shall be deemed to have been made in
compliance with this Indenture notwithstanding any subsequent adjustments made
in good faith to Iridium's financial statements affecting Consolidated Net
Income for any period.

            SECTION 4.05. Limitation on Restrictions on Distributions from
Restricted Subsidiaries. Iridium shall not, and shall not permit any Restricted
Subsidiary to, directly or indirectly, create or otherwise cause or permit to
exist or become effective any consensual encumbrance or restriction on the
ability of any Restricted Subsidiary to (i) pay dividends or make any other
distributions to Iridium or any Restricted Subsidiary on its Capital Stock or
with respect to any other interest or participation in, or measured by, its
profits, (ii) pay any Indebtedness owed to Iridium or any Restricted Subsidiary,
(iii) make any loans or advances to Iridium or any Restricted Subsidiary or (iv)
transfer any of its property or assets to Iridium or any Restricted Subsidiary,
except:
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            (1) any encumbrance or restriction pursuant to an agreement relating
      to the Guaranteed Bank Facility or any other agreement in effect at or
      entered into on the Issue Date, or any encumbrance or restriction imposed
      pursuant to this Indenture or the Notes (or similar limitations pursuant
      to other notes issued by Iridium, or indentures relating thereto, that are
      substantially similar to those set forth in this Indenture), or any
      agreement relating to the Secured Bank Facility;

            (2) any encumbrance or restriction pursuant to an agreement relating
      to any Acquired Indebtedness, which encumbrance or restriction is not
      applicable to any Person, or the properties or assets of any Person, other
      than the Person so acquired and its Subsidiaries;

            (3) any encumbrance or restriction pursuant to (x) an agreement or
      instrument pursuant to which Indebtedness which Refinances Indebtedness
      Incurred pursuant to an agreement referred to in clause (1) or (2) or this
      clause (3) is Incurred or contained in any amendment to an agreement or
      instrument referred to in clause (1) or (2) of this clause (3), or (y)
      Indebtedness described in clause (i), (ii) or (iii) of paragraph (b) of
      Section 4.03 and permitted Refinancing Indebtedness with respect thereto;
      provided, however, that the encumbrances and restrictions contained in any
      such refinancing agreement, instrument or amendment referred to in clause
      (x) above are, taken as a whole, no more restrictive in any material
      respect than the encumbrances and restrictions contained in the
      predecessor agreements (as determined by the chief financial officer of
      Iridium in good faith and evidenced by a certificate filed with the
      Trustee);

            (4) any encumbrance or restriction contained in security agreements
      or mortgages securing Indebtedness, or under any documents providing for
      Capital Lease Obligations, of a Restricted Subsidiary which are not
      prohibited by Section 4.12 herein to the extent such encumbrances or
      restrictions restrict the assignment or transfer of the property or assets
      subject to such security agreements or mortgages, or subject to such
      Capital Lease Obligations;

            (5) any encumbrance or restriction existing under or by reason of
      applicable law or regulations;

            (6) customary non-assignment provisions of any licensing agreement
      or of any lease but only to the extent such provisions restrict the
      transfer of the license, lease or the property thereunder;

            (7) any encumbrance or restriction contained in contracts for sales
      of assets otherwise permitted by this Indenture;

            (8) with respect to a Restricted Subsidiary, any encumbrance or
      restriction imposed pursuant to an agreement that has been entered into
      for the sale of all or substantially all of the Capital Stock of such
      Restricted Subsidiary; provided, however, that after giving effect to such
      transaction no Default shall have occurred or be continuing, that such
      restriction terminates if such transaction is not consummated and that
      such consummation or abandonment of such transaction occurs within one
      year of the date such agreement was entered into;

            (9) any encumbrance or restriction, with respect to a Restricted
      Subsidiary that is not a Restricted Subsidiary on the date of this
      Indenture, in existence at the time such Person becomes a Restricted
      Subsidiary and not incurred in connection with, or in contemplation of,
      such Person becoming a Restricted Subsidiary; and

            (10) any restriction on the sale or other disposition of assets or
      property securing Indebtedness as a result of a Permitted Lien on such
      assets or property.

            SECTION 4.06. Limitation on Sales of Assets and Subsidiary Stock.
(a) Iridium shall not, and shall not permit any Restricted Subsidiary to,
directly or indirectly, make any Asset Disposition unless:

            (i) Iridium or such Restricted Subsidiary, as the case may be,
      receives consideration at the time of such Asset Disposition at least
      equal to the fair market value (including the value of all non-cash
      consideration) of the shares and assets subject to such Asset Disposition,
      as determined by the Board of Directors in good faith and evidenced by a
      resolution filed with the Trustee;
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                                                                              29


            (ii) at least 80% of the consideration therefor received by Iridium
      or such Restricted Subsidiary, as the case may be, consists of cash or
      Marketable Securities (provided that an amount equal to the fair value (as
      determined in good faith by the Board of Directors as evidenced by a
      resolution filed with the Trustee) of assets utilized or to be utilized in
      a Related Business and received by Iridium or any Restricted Subsidiary in
      connection with any Asset Disposition shall be treated as cash solely for
      purposes of this clause (ii)) or the assumption of Indebtedness of Iridium
      (other than Indebtedness that is a Subordinated Obligation) or the
      Restricted Subsidiary, as the case may be, and the release of Iridium or
      such Restricted Subsidiary, as the case may be, from all liability on the
      Indebtedness assumed; and

            (iii) all Net Available Proceeds, less any amounts invested within
      180 days of such disposition (or committed by such 180th day for
      investment pursuant to a written agreement which commits such investment
      within 180 days after the date of such agreement) in assets that comply
      with Section 4.13, are applied within 180 days of such Asset Disposition
      (1) first, to the permanent repayment or reduction of Indebtedness then
      outstanding under any Bank Credit Agreement or Vendor Financing Facility,
      to the extent such agreement or facility would require such application or
      prohibit payments pursuant to the following clause (2), (2) second, to the
      extent of remaining Net Available Proceeds, to make an Offer to Purchase
      outstanding Notes at a purchase price in cash equal to 100% of the
      principal amount of the Notes plus accrued and unpaid interest to the date
      of purchase and, to the extent required by the terms thereof, any other
      Indebtedness of Iridium or a Restricted Subsidiary that ranks pari passu
      with the Notes at a purchase price no greater than 100% of the principal
      amount thereof plus accrued and unpaid interest to the date of purchase
      and (3) third, to the extent of any remaining Net Available Proceeds after
      application of clauses (1) and (2) of this Section 4.06(a)(iii), to the
      repayment of other Indebtedness of Iridium or Indebtedness of a Restricted
      Subsidiary, to the extent permitted under the terms thereof. To the extent
      any Net Available Proceeds remain after such uses, Iridium and the
      Restricted Subsidiaries may use such amounts for any purposes not
      prohibited by this Indenture. Notwithstanding the foregoing, Iridium shall
      not be required to repurchase or redeem Notes pursuant to clause (2) of
      this Section 4.06(a)(iii) until Net Available Proceeds from all Asset
      Dispositions in the aggregate, less (x) any amounts invested within 180
      days of such dispositions (or committed by such 180th day for investment
      pursuant to a written agreement which commits such investment within 180
      days after the date of such agreement) in a Related Business, (y) any
      amounts applied pursuant to clause (1) above and (z) any amounts
      previously applied pursuant to clause (1), (2) or (3) of this Section
      4.06(a)(iii), are greater than $10,000,000.

            (b) The Note Issuers shall comply, to the extent applicable, with
the requirements of Section 14(e) of the Exchange Act and any other securities
laws or regulations in connection with the repurchase of Notes pursuant to this
Section 4.06. To the extent that the provisions of any securities laws or
regulations conflict with provisions of this covenant, the Issuers shall comply
with the applicable securities laws and regulations and shall not be deemed to
have breached their obligations described under Section 4.06 by virtue thereof.

            SECTION 4.07. Limitation on Transactions with Affiliates. (a)
Iridium shall not, and shall not permit any Restricted Subsidiary to, directly
or indirectly, enter into any transaction (including the purchase, sale, lease
or exchange of any property or the rendering of any service) with any Affiliate
or Related Person of Iridium (other than Iridium or a Wholly-Owned Restricted
Subsidiary) that involves consideration in excess of $5,000,000 (an "Affiliate
Transaction") on terms (i) that, taken as a whole, are less favorable to Iridium
or such Restricted Subsidiary, as the case may be, than those that could be
obtained at the time of such transaction in arm's-length dealings with a Person
who is not such an Affiliate and (ii) that, in the event such Affiliate
Transaction involves an aggregate amount in excess of $10,000,000, are not in
writing and have not been approved either by a majority of the members of the
Board of Directors having no material direct or indirect financial interest in
or with respect to such Affiliate Transaction or by the Related Party Contracts
Committee, as defined by the Iridium Operating LLC Agreement (if appropriate
under Iridium's Bylaws or the Iridium Operating LLC Agreement). In addition, if
such Affiliate Transaction is an Asset Disposition involving any Affiliate or
Related Person of Iridium (other than Iridium or a Wholly-Owned Restricted
Subsidiary) for an aggregate consideration in excess of $25,000,000, a fairness
opinion to the effect that such transaction is fair (from a financial point of
view) to Iridium or the Restricted Subsidiary, as applicable, must be obtained
from an Independent Financial Advisor or, with respect to
telecommunications-related matters, a recognized expert in the satellite
telecommunications industry.

            (b) The provisions of the paragraph (a) of this Section 4.07 shall
not apply to:
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                                                                              30


                  (i) employee benefit or compensation arrangements entered into
         in the ordinary course of business and approved by the Board of
         Directors;

                  (ii) transactions solely between or among Iridium and the
         Restricted Subsidiaries;

                  (iii) Restricted Payments permitted by Section 4.04;

                  (iv) Investments by IWCL, an Affiliate or Related Person of
         Iridium or Capital in the Capital Stock (other than Disqualified Stock)
         of Iridium or any Restricted Subsidiary; and

                  (v) a transaction pursuant to an Existing Affiliate Agreement,
         including any amendments thereto entered into after the Issue Date,
         provided that the terms of any such amendment are not, taken as a
         whole, less favorable to Iridium than the terms of the relevant
         agreement prior to such amendment.

                  SECTION 4.08. Change of Control. (a) Upon the occurrence of a
Change of Control, each Holder shall have the right to require the Note Issuers
to repurchase all or any part of such Holder's Notes at a purchase price in cash
equal to 101% of the principal amount of the Notes, plus accrued and unpaid
interest to the date of purchase (subject to the right of Holders of record on
the relevant record date to receive interest due on the relevant interest
payment date in accordance with the terms of this Indenture); provided, however,
that notwithstanding the occurrence of a Change of Control, the Note Issuers
shall not be obligated to purchase any Note pursuant to this Section 4.08 to the
extent that the Note Issuers have exercised their rights to redeem such Note as
described in Section 3.07.

                  (b) Within 30 days following any Change of Control, the Note
Issuers shall mail a notice to each Holder with a copy to the Trustees stating,
among other things: (1) that a Change of Control has occurred and that such
Holder has the right to require the Note Issuers to purchase all or any portion
of such Holder's Notes at a purchase price in cash equal to 101% of the
principal amount of such Notes, plus accrued and unpaid interest to the date of
purchase (subject to the right of Holders of record on a record date to receive
interest due on the relevant interest payment date in accordance with the terms
of this Indenture); (2) the circumstances and relevant facts regarding such
Change of Control (including information with respect to pro forma historical
income, cash flow and capitalization, each after giving effect to such Change of
Control); (3) the repurchase date (which shall be no earlier than 30 days nor
later than 60 days from the date such notice is mailed); and (4) the
instructions determined by the Note Issuers, consistent with this Section 4.08,
that a Holder must follow in order to have its Notes or any portion thereof
purchased.

                  (c) The Note Issuers shall comply, to the extent applicable,
with the requirements of Section 14(e) of the Exchange Act and any other
securities laws or regulations in connection with the repurchase of Notes
pursuant to this Section 4.08. To the extent that the provisions of any
securities laws or regulations conflict with provisions of this Section 4.08,
the Note Issuers shall comply with the applicable securities laws and
regulations and shall not be deemed to have breached their obligations described
above by virtue thereof.

                  SECTION 4.09. Compliance Certificate. The Note Issuers shall
deliver to the Trustee within 120 days after the end of each fiscal year of the
Note Issuers an Officers' Certificate complying with Section 314(a)(4) of the
TIA and stating that in the course of the performance by the signers of their
duties as Officers of the Note Issuers they would normally have knowledge of any
Default or Event of Default and, if such signer does know of such a Default or
Event of Default, the certificate shall describe such Default or Event of
Default with particularity and describe what actions, if any, the Note Issuers
propose to take with respect to such Default or Event of Default.

                  SECTION 4.10. [Reserved]

                  SECTION 4.11. Limitation on the Sale or Issuance of Capital
Stock of Restricted Subsidiaries. Iridium shall not, and shall not permit any
Restricted Subsidiary to, issue, transfer, convey, sell or otherwise dispose of
any shares of Capital Stock of a Restricted Subsidiary or securities convertible
or exchangeable into Capital Stock of a Restricted Subsidiary to any person
other than Iridium, Capital or a Wholly-Owned Restricted Subsidiary except (i)
in a transaction consisting of a sale of all the Capital Stock of such
Restricted Subsidiary and that complies with Section 4.06 to the extent such
provisions apply; (ii) if required, the issuance, transfer, conveyance, sale or
other disposition of directors' qualifying shares or of interests required to be
held by foreign nationals, in each case to the extent mandated by applicable
law; (iii) in a transaction in which, or in connection with which,
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                                                                              31


Iridium or a Restricted Subsidiary acquires at the same time sufficient Capital
Stock of such Restricted Subsidiary to at least maintain the same percentage
ownership interest it had prior to such transaction; (iv) any grant,
establishment or exercise of any Lien permitted under Section 4.12; and (v)
Disqualified Stock of a Restricted Subsidiary Incurred to Refinance Disqualified
Stock of such Restricted Subsidiary; provided, however, that the amounts of the
redemption obligations of such Disqualified Stock may not exceed the amounts of
the redemption obligations of, and such Disqualified Stock shall have redemption
obligations no earlier than those required by, the Disqualified Stock being
Refinanced.

                  SECTION 4.12. Limitation on Liens. (a) Iridium shall not, and
shall not permit any Restricted Subsidiary to, directly or indirectly, create or
permit to exist any Lien on any of its property or assets (including Capital
Stock), whether owned on the Issue Date or thereafter acquired, unless
contemporaneously therewith effective provision is made to secure the Notes
equally and ratably with such obligation for so long as such obligation is so
secured. The preceding sentence shall not require Iridium or any Restricted
Subsidiary to equally and ratably secure the Notes if the Lien consists of
Permitted Liens.

                  (b) Any Lien created for the benefit of the Holders of the
Notes pursuant to Section 4.12(a) shall provide by its terms that such Lien
shall be automatically and unconditionally released and discharged upon the
earlier of the release and discharge of the Lien which gave rise to the
obligation to secure the Notes and the release and discharge of this Indenture.

                  SECTION 4.13. Limitation on Lines of Business. Iridium shall
not, and shall not permit any Restricted Subsidiary to, engage in any business
other than a Related Business.

                  SECTION 4.14. Limitation on Business Activities of Capital.
Capital shall not hold any material assets, become liable for any material
obligations, engage in any trade or business, or conduct any business activity,
other than the issuance of Capital Stock to Iridium or any Wholly-Owned
Restricted Subsidiary, the Incurrence of Indebtedness as a co-obligor or
guarantor of Indebtedness Incurred by Iridium (including the Notes) that is
permitted to be Incurred by Iridium pursuant to Section 4.03 (provided that the
net proceeds of such Indebtedness are retained or utilized by Iridium or loaned
to one or more of Iridium's Restricted Subsidiaries other than Capital), and
activities incidental thereto. Neither Iridium nor any Restricted Subsidiary
(other than Capital) shall engage in any transactions with Capital in violation
of the immediately preceding sentence.

                  SECTION 4.15. Future Guarantor Subsidiaries. Iridium shall
cause each Subsidiary created or acquired after the Issue Date (other than an
Unrestricted Subsidiary or a Foreign Subsidiary) to execute and deliver to the
Trustee a supplemental indenture, substantially in the form of Exhibit B,
pursuant to which such Subsidiary shall Guarantee payment of the Notes. Iridium
may cause any Foreign Subsidiary to execute and deliver a Subsidiary Guaranty in
accordance with the provisions of this Indenture. Each Subsidiary Guaranty shall
be limited to an amount not to exceed the maximum amount that can be Guaranteed
by that Subsidiary without rendering the Subsidiary Guaranty, as it relates to
such Subsidiary, voidable under applicable law relating to fraudulent conveyance
or fraudulent transfer or similar laws affecting the rights of creditors
generally. In addition, the Note Issuers shall not, and shall not permit any of
the Guarantor Subsidiaries to, make any Investment in any Subsidiary that is not
a Guarantor Subsidiary unless either (i) such Investment is permitted by Section
4.04 or (ii) such Subsidiary executes and delivers a Subsidiary Guaranty in
accordance with the provisions of this Indenture.

                  SECTION 4.16. Maintenance of Insurance. Iridium shall procure
and maintain insurance with financially sound and reputable insurance companies
in such amounts, with such deductibles and covering such risks as is customarily
carried by companies engaged in a business or businesses similar to Iridium and
owning properties in localities where Iridium and the Restricted Subsidiaries
operate, including without limitation in-orbit insurance.

                  Within 30 days following the Issue Date and within 30 days
following any date on which Iridium renews or obtains insurance, Iridium shall
deliver to the Trustee an insurance certificate certifying the amount of
insurance then renewed or obtained and an Officers' Certificate stating that
such insurance, together with any other insurance, complies with this Section
4.16. In addition, Iridium shall cause to be delivered to the Trustee no less
than once each year an insurance certificate setting forth the amount of
insurance then carried, which insurance certificate shall entitle the Trustee to
(i) notice of any claim under any such insurance policy; and (ii) at least 30
days' notice from the provider of such insurance prior to the cancellation of
any such insurance.
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                                                                              32


                  In the event that Iridium receives any proceeds of any
in-orbit insurance, such proceeds shall constitute "Insurance Proceeds."
Promptly following the receipt of any Insurance Proceeds, Iridium shall apply
such Insurance Proceeds in accordance with Section 4.06(a)(iii) (treating such
Insurance Proceeds as Net Available Proceeds thereunder); provided, however,
that Insurance Proceeds shall only be required to be so applied to the extent
that the aggregate amount of all Insurance Proceeds received by Iridium exceeds
$10,000,000 in any 12-month period.

                                    ARTICLE V

                               Successor Companies

                  SECTION 5.01. When Issuers May Merge or Transfer Assets. (a)
Neither Note Issuer shall consolidate with or merge with or into, or convey,
transfer or lease, in one transaction or a series of transactions, all or
substantially all its assets to any Person unless:

                  (i) the resulting, surviving or transferee Person (the
         "Successor Company") shall be a Person organized and existing under the
         laws of the United States of America, any State thereof or the District
         of Columbia or the laws of Bermuda and the Successor Company (if not
         Iridium) shall expressly assume, by an indenture supplemental hereto,
         executed and delivered to the Trustee, in form satisfactory to the
         Trustee, all the obligations of Iridium under the Notes and this
         Indenture;

                  (ii) immediately after giving effect to such transaction on a
         pro forma basis (and treating any Indebtedness which becomes an
         obligation of the Successor Company or any Subsidiary as a result of
         such transaction as having been Incurred by such Successor Company or
         such Subsidiary at the time of such transaction), no Default shall have
         occurred and be continuing;

                  (iii) immediately after giving effect to such transaction, the
         Successor Company would be able to Incur an additional $1.00 of
         Indebtedness under Section 4.03(a);

                  (iv) immediately after giving effect to such transaction, the
         Successor Company shall have Consolidated Net Worth in an amount which
         is not less than the Consolidated Net Worth of Iridium immediately
         prior to such transaction; and

                  (v) Iridium shall have delivered to the Trustee an Officers'
         Certificate and an Opinion of Counsel, each stating that such
         consolidation, merger or transfer and such supplemental indenture (if
         any) comply with this Indenture.

The requirements of clause (iii) above shall not apply where Iridium merges with
or into, or conveys, transfers or leases, in one transaction or a series of
transactions, all or substantially all of its assets to, any Person with no
outstanding Indebtedness (other than Indebtedness which is also Indebtedness of
Iridium).

                  (b) Iridium shall not permit any Guarantor Subsidiary to
consolidate with or merge with or into, or convey, transfer or lease, in one
transaction or a series of transactions, all or substantially all of its assets
to any Person unless: (i) the resulting, surviving or transferee Person (if not
such Subsidiary) is a Person organized and existing under the laws of the
jurisdiction under which such Subsidiary was organized or under the laws of the
United States of America, or any State thereof, the District of Columbia or the
laws of Bermuda, and such Person expressly assumes, by a guaranty agreement, in
a form satisfactory to the Trustee, all the obligations of such Subsidiary, if
any, under its related Subsidiary Guaranty (except to the extent it would not
otherwise have been required to provide a Subsidiary Guaranty); (ii) immediately
after giving effect to such transaction on a pro forma basis (and treating any
Indebtedness which becomes an obligation of the resulting, surviving or
transferee Person as a result of such transaction as having been issued by such
Person at the time of such transaction), no Default has occurred and is
continuing under this Indenture; and (iii) Iridium has delivered to the Trustee
an Officer's Certificate and an Opinion of Counsel, each stating that such
consolidation, merger or transfer and such guaranty agreement, if any, complies
with this Indenture.
   38
                                                                              33


                  (c) The Successor Company shall be the successor to Iridium
and shall succeed to, and be substituted for, and may exercise every right and
power of, Iridium, Capital or any Guarantor Subsidiary, respectively, under this
Indenture, the Notes and the related Subsidiary Guaranty, as applicable, and the
predecessor Iridium, Capital or Guarantor Subsidiary, respectively (other than
in the case of a lease), shall be released from all obligations and covenants
under this Indenture and the Notes or the related Subsidiary Guaranty, as
applicable.

                                   ARTICLE VI

                              Defaults and Remedies

                  SECTION 6.01. Events of Default. An "Event of Default" occurs
if:

                  (1) a default occurs in any payment of interest on any Note
         when the same becomes due and payable, and such default continues for a
         period of 30 days;

                  (2) a default occurs in the payment of the principal of any
         Note when the same becomes due and payable at its Stated Maturity, upon
         optional redemption, upon required repurchase, upon declaration or
         otherwise;

                  (3) either Note Issuer fails to comply with Section 5.01;

                  (4) either Note Issuer fails to comply with Section 4.03,
         4.04, 4.05, 4.06, 4.07, 4.08, 4.11, 4.12, 4.13, 4.14, 4.15 and 4.16 (in
         each case, other than a failure to purchase Notes when required under
         Section 4.06 or 4.08) and such failure continues for 30 days after the
         notice specified in the penultimate paragraph of this Section 6.01;

                  (5) any Note Issuer or Guarantor Subsidiary fails to comply
         with any of its agreements in the Notes or this Indenture (other than
         those referred to in clause (1), (2), (3) or (4) above) and such
         failure continues for 60 days after the notice specified in the
         penultimate paragraph 6.01;

                  (6) any Note Issuer or Significant Subsidiary fails to pay any
         Indebtedness of such Person within any applicable grace period after
         final maturity or the acceleration of any such Indebtedness by the
         holders of such Indebtedness because of a default and the total amount
         of such Indebtedness unpaid or accelerated exceeds $10,000,000 or its
         foreign currency equivalent at the time;

                  (7) any Note Issuer or Significant Subsidiary pursuant to or
         within the meaning of any Bankruptcy Law:

                           (A) commences a voluntary case;

                           (B) consents to the entry of an order for relief
                  against it in an involuntary case;

                           (C) consents to the appointment of a Custodian of it
                  or for any substantial part of its property;

                           (D) makes a general assignment for the benefit of its
                  creditors; or

                           (E) takes any comparable action under any foreign
                  laws relating to insolvency;

                  (8) a court of competent jurisdiction enters an order or
         decree under any Bankruptcy Law that:

                           (A) is for relief against any Note Issuer or
                  Significant Subsidiary in an involuntary case;

                           (B) appoints a Custodian of any Note Issuer or
                  Significant Subsidiary or for any substantial part of its
                  property;
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                                                                              34


                           (C) orders the winding up or liquidation of any Note
                  Issuer or Significant Subsidiary; or

                           (D) any similar relief is granted under foreign laws;

         and the order or decree remains unstayed and in effect for 60 days;

                  (9) the rendering of any final judgment or decree (not subject
         to appeal) in excess of $10,000,000 or its foreign currency equivalent
         (net of amounts paid within 30 days of such judgment or decree under
         any insurance, indemnity, bond, surety or similar instrument) against
         any Note Issuer or Significant Subsidiary by a court or other
         adjudicatory authority of competent jurisdiction to the extent which
         such Note Issuer or Significant Subsidiary, as applicable, is not
         insured by a third Person and such judgment or decree remains
         outstanding and is not discharged, waived or stayed within 30 days
         after the notice specified in the penultimate paragraph of this Section
         6.01;

                  (10) any Subsidiary Guaranty ceases to be in full force and
         effect (except as contemplated by the terms thereof) or any Guarantor
         Subsidiary shall deny or disaffirm its obligations under this Indenture
         or any Subsidiary Guaranty;

                  (11) termination by Motorola of the Space System Contract
         prior to delivery thereunder by Motorola of the Space System (as
         defined therein), provided that such termination has not been contested
         by Iridium in accordance with the Space System Contract or by
         appropriate proceedings and, if such termination is so contested,
         within 180 days of such notice such termination has not been withdrawn
         or declared ineffective by any recognized court or mediator; or

                  (12) termination by Motorola of the Operation and Maintenance
         Contract, or Motorola ceases to be the operator of the IRIDIUM System
         prior to the Stated Maturity of the Notes, in each such case for a
         period of more than 30 days.

                  The foregoing shall constitute Events of Default whatever the
reason for any such Event of Default and whether it is voluntary or involuntary
or is effected by operation of law or pursuant to any judgment, decree or order
of any court or any order, rule or regulation of any administrative or
governmental body.

                  The term "Bankruptcy Law" means Title 11, United States Code,
or any similar Federal or state law for the relief of debtors. The term
"Custodian" means any receiver, trustee, assignee, liquidator, custodian or
similar official under any Bankruptcy Law.

                  A Default under clause (4), (5) or (9) shall not constitute an
Event of Default until the Trustee or the Holders of at least 25% in principal
amount of the outstanding Notes notify the Note Issuers of the Default and the
Note Issuers do not cure such Default within the time specified in clauses (4),
(5), or (9) hereof after receipt of such notice.

                  The Note Issuers shall deliver to the Trustee, within 30 days
thereof, written notice in the form of an Officers' Certificate of any Event of
Default under clause (3), (6), (7) or (10) and any event which with the giving
of notice or the lapse of time would become an Event of Default under clause
(4), (5), (8), (9), (11) or (12), its status and what action Iridium is taking
or proposes to take in respect thereof.

                  SECTION 6.02. Acceleration. If an Event of Default (other than
an Event of Default specified in Section 6.01(7) or 6.01(8) with respect to
either Note Issuer) occurs and is continuing, the Trustee by notice to the Note
Issuers, or the Holders of at least 25% in principal amount of the outstanding
Notes by notice to the Note Issuers and the Trustee, may declare the principal
of and accrued but unpaid interest on all of the Notes to be due and payable.
Upon such a declaration, such principal and interest shall be due and payable
immediately. If an Event of Default specified in Section 6.01(7) or 6.01(8) with
respect to either Note Issuer occurs and is continuing, the principal of and
interest on all the Notes shall ipso facto become and be immediately due and
payable without any declaration or other act on the part of the Trustee or any
Holders. The Holders of a majority in principal amount of the Notes by notice to
the Trustee may rescind an acceleration and its consequences if the rescission
would not conflict with any judgment or decree and if all existing Events of
Default have been cured or waived except
   40
                                                                              35


nonpayment of principal or interest that has become due solely because of
acceleration. No such rescission shall affect any subsequent Default or impair
any right consequent thereto.

                  SECTION 6.03. Other Remedies. If an Event of Default occurs
and is continuing, the Trustee may pursue any available remedy to collect the
payment of principal of or interest on the Notes or to enforce the performance
of any provision of the Notes or this Indenture.

                  The Trustee may maintain a proceeding even if it does not
possess any of the Notes or does not produce any of them in the proceeding. A
delay or omission by the Trustee or any Holder in exercising any right or remedy
accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default. No remedy is
exclusive of any other remedy. All available remedies are cumulative.

                  SECTION 6.04. Waiver of Past Defaults. The Holders of a
majority in principal amount of the Notes by written notice to the Trustee may
waive an existing Default and its consequences except (i) a Default in the
payment of the principal of or interest on a Note or (ii) a Default in respect
of a provision that under Section 9.02 cannot be amended without the consent of
each Holder affected. When a Default is waived, it is deemed cured, but no such
waiver shall extend to any subsequent or other Default or impair any consequent
right.

                  SECTION 6.05. Control by Majority. The Holders of a majority
in principal amount of the outstanding Notes may direct the time, method and
place of conducting any proceeding for any remedy available to the Trustee or of
exercising any trust or power conferred on the Trustee. However, the Trustee may
refuse to follow any direction that conflicts with law or this Indenture or,
subject to Section 7.01, that the Trustee determines is unduly prejudicial to
the rights of other Holders or would involve the Trustee in personal liability.
Prior to taking any action hereunder, the Trustee shall be entitled to
indemnification satisfactory to it in its sole discretion against all losses and
expenses caused by taking or not taking such action.

                  SECTION 6.06. Limitation on Suits. A Holder may not pursue any
remedy with respect to this Indenture or the Notes unless:

                  (1) the Holder gives to the Trustee written notice stating
         that an Event of Default is continuing;

                  (2) the Holders of at least 25% in principal amount of the
         Notes then outstanding make a written request to the Trustee to pursue
         the remedy;

                  (3) such Holder or Holders offer to the Trustee reasonable
         security or indemnity against any loss, liability or expense;

                  (4) the Trustee does not comply with the request within 60
         days after receipt of the request and the offer of security or
         indemnity; and

                  (5) the Holders of a majority in principal amount of the Notes
         do not give the Trustee a direction inconsistent with the request
         during such 60-day period.

                  A Holder may not use this Indenture to prejudice the rights of
another Holder or to obtain a preference or priority over another Holder.

                  SECTION 6.07. Rights of Holders to Receive Payment.
Notwithstanding any other provision of this Indenture, the right of any Holder
to receive payment of principal of and interest on the Notes held by such
Holder, on or after the respective due dates expressed in the Notes, or to bring
suit for the enforcement of any such payment on or after such respective dates,
shall not be impaired or affected without the consent of such Holder.

                  SECTION 6.08. Collection Suit by Trustee. If an Event of
Default specified in Section 6.01(1) or 6.01(2) occurs and is continuing, the
Trustee may recover judgment in its own name and as trustee of an express trust
against the Note Issuers for the whole amount then due and owing (together with
interest on any unpaid interest to the extent lawful) and the amounts provided
for in Section 7.07.
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                  SECTION 6.09. Trustee May File Proofs of Claim. The Trustee
may file such proofs of claim and other papers or documents and take such other
actions, including participating as a member, voting or otherwise, of any
committee of creditors appointed in the matter, as may be necessary or advisable
in order to have the claims of the Trustee and the Holders allowed in any
judicial proceedings relative to the Note Issuers, any Guarantor Subsidiary,
their respective creditors or their property and, unless prohibited by law or
applicable regulations, may vote on behalf of the Holders in any election of a
trustee in bankruptcy or other Person performing similar functions, and any
Custodian in any such judicial proceeding is hereby authorized by each Holder to
make payments to the Trustee and, in the event that the Trustee shall consent to
the making of such payments directly to the Holders, to pay to the Trustee any
amount due it for the reasonable compensation, expenses, disbursements and
advances of the Trustee, its agents and its counsel, and any other amounts due
the Trustee under Section 7.07.

                  Nothing herein shall be deemed to empower the Trustee to
authorize or consent to, or accept or adopt on behalf of any Holder, any plan of
reorganization, arrangement, adjustment or composition affecting the Notes or
the rights of any Holder, or to authorize the Trustee to vote in respect of the
claim of any Holder in any such proceeding.

                  SECTION 6.10. Priorities. If the Trustee collects any money or
property from the Issuers pursuant to this Article VI, it shall pay out the
money or property in the following order:

                  FIRST: to the Trustee for amounts due under Section 7.07;

                  SECOND: to Holders for amounts due and unpaid on the Notes for
         principal and interest, ratably, without preference or priority of any
         kind, according to the amounts due and payable on the Notes for
         principal and interest, respectively; and

                  THIRD: to Iridium.

                  The Trustee may fix a record date and payment date for any
payment to Holders pursuant to this Section 6.10 At least 15 days before such
record date, the Trustee shall mail to each Holder and the Note Issuers a notice
that states the record date, the payment date and amount to be paid.

                  SECTION 6.11. Undertaking for Costs. In any suit for the
enforcement of any right or remedy under this Indenture or in any suit against
the Trustee for any action taken or omitted by it as Trustee, a court in its
discretion may require the filing by any party litigant in the suit of an
undertaking to pay the costs of the suit, and the court in its discretion may
assess reasonable costs, including reasonable attorneys' fees, against any party
litigant in the suit, having due regard to the merits and good faith of the
claims or defenses made by the party litigant. This Section 6.11 does not apply
to a suit by the Note Issuers, a suit by the Trustee, a suit by a Holder
pursuant to Section 6.07 or a suit by Holders of more than 10% in principal
amount of the Notes.

                  SECTION 6.12. Waiver of Stay or Extension Laws. The Issuers
(to the extent either may lawfully do so) shall not at any time insist upon, or
plead, or in any manner whatsoever claim or take the benefit or advantage of,
any stay or extension law wherever enacted, now or at any time hereafter in
force, which may affect the covenants or the performance of this Indenture, any
of the Subsidiary Guaranties or any of the Notes; and the Issuers (to the extent
that either may lawfully do so) hereby expressly waive all benefit or advantage
of any such law, and shall not hinder, delay or impede the execution of any
power herein granted to the Trustee, but shall suffer and permit the execution
of every such power as though no such law had been enacted.

                  SECTION 6.13. Restoration of Rights and Remedies. If the
Trustee or any Holder has instituted any proceeding to enforce any right or
remedy under this Indenture and such proceeding has been discontinued or
abandoned for any reason, or has been determined adversely to the Trustee or to
such Holder, then, and in every such case, subject to any determination in such
proceeding, the Issuers, the Trustee and the Holders shall be restored severally
and respectively to their former positions hereunder and thereafter all rights
and remedies of the Issuers, Trustee and Holders shall continue as though no
such proceeding had been instituted.
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                                                                              37


                                   ARTICLE VII

                                     Trustee

                  SECTION 7.01. Duties of Trustee. (a) If an Event of Default
has occurred and is continuing, the Trustee shall exercise the rights and powers
vested in it by this Indenture and use the same degree of care and skill in its
exercise as a prudent Person would exercise or use under the circumstances in
the conduct of such Person's own affairs.

                  (b) Except during the continuance of an Event of Default:

                  (1) the Trustee undertakes to perform such duties and only
         such duties as are specifically set forth in this Indenture and no
         implied covenants or obligations shall be read into this Indenture
         against the Trustee; and

                  (2) in the absence of bad faith on its part, the Trustee may
         conclusively rely, as to the truth of the statements and the
         correctness of the opinions expressed therein, upon certificates or
         opinions furnished to the Trustee and conforming to the requirements of
         this Indenture. However, the Trustee shall examine the certificates and
         opinions to determine whether or not they conform to the requirements
         of this Indenture.

                  (c) The Trustee may not be relieved from liability for its own
negligent action, its own negligent failure to act or its own wilful misconduct,
except that:

                  (1) this paragraph does not limit the effect of paragraph (b)
         of this Section 7.01 and Section 7.02(e);

                  (2) the Trustee shall not be liable for any error of judgment
         made in good faith by a Trust Officer unless it is proved that the
         Trustee was negligent in ascertaining the pertinent facts; and

                  (3) the Trustee shall not be liable with respect to any action
         it takes or omits to take in good faith in accordance with a written
         direction received by it pursuant to Section 6.05.

                  (d) Every provision of this Indenture that in any way relates
to the Trustee is subject to paragraphs (a), (b) and (c) of this Section.

                  (e) The Trustee shall not be liable for interest on any money
received by it except as the Trustee may agree in writing with the Issuers.

                  (f) Money held in trust by the Trustee need not be segregated
from other funds except to the extent required by law.

                  (g) No provision of this Indenture shall require the Trustee
to expend or risk its own funds or otherwise incur financial liability in the
performance of any of its duties hereunder or in the exercise of any of its
rights or powers, if it shall have reasonable grounds to believe that repayment
of such funds or adequate indemnity against such risk or liability is not
reasonably assured to it.

                  (h) Every provision of this Indenture relating to the conduct
or affecting the liability of or affording protection to the Trustee shall be
subject to the provisions of this Section 7.01 and to the provisions of the TIA.

                  SECTION 7.02. Rights of Trustee. Subject to Section 7.01:

                  (a) The Trustee may conclusively rely on any document believed
by it to be genuine and to have been signed or presented by the proper person.
The Trustee need not investigate any fact or matter stated in the document.
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                                                                              38


                  (b) Before the Trustee acts or refrains from acting, it may
require an Officers' Certificate or an Opinion of Counsel. The Trustee shall not
be liable for any action it takes or omits to take in good faith in reliance on
the Officers' Certificate or Opinion of Counsel.

                  (c) The Trustee may act through agents and shall not be
responsible for the misconduct or negligence of any agent appointed with due
care.

                  (d) The Trustee shall not be liable for any action it takes or
omits to take in good faith which it believes to be authorized or within its
rights or powers; provided, however, that the Trustee's conduct does not
constitute wilful misconduct or negligence.

                  (e) The Trustee may consult with counsel, and the advice or
opinion of counsel with respect to legal matters relating to this Indenture and
the Notes shall be full and complete authorization and protection from liability
in respect to any action taken, omitted or suffered by it hereunder in good
faith and in accordance with the advice or opinion of such counsel.

                  (f) The Trustee shall be under no obligation to exercise any
of the rights or powers created in it by this Indenture at the request or
direction of any of the Holders pursuant to this Indenture, unless such Holders
shall have offered to the Trustee reasonable security or indemnity against the
costs, expenses and liabilities which might be incurred by it in compliance with
such request or direction.

                  (g) The Trustee shall not be bound to make any investigation
into the facts or matters stated in any document, but the Trustee, in its
discretion, may make such further inquiry or investigation into such facts or
matters as it may see fit.

                  SECTION 7.03. Individual Rights of Trustee. The Trustee in its
individual or any other capacity may become the owner or pledgee of Notes and
may otherwise deal with the Issuers or its Affiliates with the same rights it
would have if it were not Trustee. Any Paying Agent, Registrar, co-registrar or
co-paying agent may do the same with like rights. However, the Trustee must
comply with Sections 7.10 and 7.11.

                  SECTION 7.04. Trustee's Disclaimer. The Trustee shall not be
responsible for and makes no representation as to the validity or adequacy of
this Indenture or the Notes, it shall not be accountable for the Note Issuers'
use of the proceeds from the Notes, it shall not be responsible for the use or
application of any monies received by a Paying Agent other than the Trustee, and
it shall not be responsible for any statement of the Issuers in this Indenture
or in any document issued in connection with the sale of the Notes or in the
Notes other than the Trustee's certificate of authentication.

                  SECTION 7.05. Notice of Defaults. If a Default occurs and is
continuing and if it is known to the Trustee, the Trustee shall mail to each
Holder notice of such Default within the earlier of 90 days after it occurs or
30 days after it is known to a Trust Officer or written notice of it is received
by the Trustee. Except in the case of a Default in payment of principal of,
premium or interest on any Note, the Trustee may withhold notice if and so long
as a committee of its Trust Officers in good faith determines that withholding
the notice is in the interests of Holders.

                  SECTION 7.06. Reports by Trustee to Holders. As promptly as
practicable after each May 15 beginning with May 15, 1998, and in any event
prior to July 15 in each year, the Trustee shall mail to each Holder a brief
report dated as of July 15 that complies with TIA Section 313(a) (but if no
event described in TIA Section 313(a) has occurred within the twelve months
preceding the reporting date, no report shall be transmitted). The Trustee shall
also comply with TIA Section 313(b) and TIA Section 313(c).

                  A copy of each report at the time of its mailing to Holders
shall be filed with the SEC and each stock exchange (if any) on which the Notes
are listed. The Note Issuers agrees to notify promptly the Trustee whenever the
Notes become listed on any stock exchange and of any delisting thereof.

                  SECTION 7.07. Compensation and Indemnity. The Note Issuers
shall pay to the Trustee, Paying Agent and Registrar from time to time
reasonable compensation for its services as agreed between the Note Issuers and
the Trustee, Paying Agent and Registrar. The Trustee's compensation shall not be
limited by any law on compensation of a trustee of an express trust. The Issuers
shall reimburse the Trustee upon request for all
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                                                                              39


reasonable out-of-pocket expenses incurred or made by it, including costs of
collection, in addition to the compensation for its services. Such expenses
shall include the reasonable compensation and expenses, disbursements and
advances of the Trustee's agents, counsel, accountants and other professionals.
The Note Issuers shall indemnify the Trustee, Paying Agent, Registrar, and each
of their officers, directors and employees (each in their respective
capacities), for and hold each of them harmless against any and all loss,
liability or expense (including attorneys' fees) incurred by them without
negligence or bad faith on their part in connection with the administration of
this trust and the performance of their duties hereunder, including the
reasonable costs and expenses of defending itself against any claim or liability
in connection with the acceptance, exercise or performance of any of its powers
or duties hereunder. The Trustee, Paying Agent and Registrar shall notify the
Note Issuers of any claim for which they may seek indemnity promptly upon
obtaining knowledge thereof; provided, however that any failure so to notify the
Note Issuers shall not relieve the Note Issuers of their indemnity obligations
hereunder except to the extent the Issuers shall have been adversely affected
thereby. The Note Issuers shall defend the claim and the indemnified party shall
provide reasonable cooperation at the Note Issuers' expense in the defense. Such
indemnified parties may have separate counsel and the Note Issuers shall pay the
fees and expenses of such counsel; provided, however that the Note Issuers shall
not be required to pay such fees and expenses if it assumes such indemnified
parties' defense and, in such indemnified parties' reasonable judgment, there is
no conflict of interest between the Note Issuers and such parties in connection
with such defense. The Note Issuers need not pay for any settlement made without
their written consent. The Note Issuers need not reimburse any expense or
indemnify against any loss, liability or expense incurred by an indemnified
party through such party's own willful misconduct, negligence or bad faith.

                  The Note Issuers' payment obligations pursuant to this Section
7.07 shall survive the discharge of this Indenture. When the Trustee, Paying
Agent or Registrar incurs expenses after the occurrence of a Default specified
in Section 6.01(7) or 6.01(8) with respect to the Issuers, the expenses are
intended to constitute expenses of administration under the Bankruptcy Law.

                  SECTION 7.08. Replacement of Trustee. The Trustee may resign
at any time by so notifying the Note Issuers in writing. The Holders of a
majority in principal amount of the Notes may remove the Trustee by so notifying
the Note Issuers and the Trustee and may appoint a successor Trustee with the
consent of the Note Issuers, which shall not be unreasonably withheld. The Note
Issuers shall remove the Trustee if:

                  (1) the Trustee fails to comply with Section 7.10;

                  (2) the Trustee is adjudged bankrupt or insolvent;

                  (3) a receiver or other public officer takes charge of the
         Trustee or its property; or

                  (4) the Trustee otherwise becomes incapable of acting.

                  If the Trustee resigns, is removed by the Note Issuers or by
the Holders of a majority in principal amount of the Notes and such Holders do
not reasonably promptly appoint a successor Trustee, or if a vacancy exists in
the office of Trustee for any reason (the Trustee in such event being referred
to herein as the retiring Trustee), the Note Issuers shall promptly appoint a
successor Trustee.

                  A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Note Issuers. Thereupon the
resignation or removal of the retiring Trustee shall become effective, and the
successor Trustee shall have all the rights, powers and duties of the Trustee
under this Indenture. The successor Trustee shall mail a notice of its
succession to Holders. The retiring Trustee shall promptly transfer all property
held by it as Trustee to the successor Trustee.

                  If a successor Trustee does not take office within 60 days
after the retiring Trustee resigns or is removed, the retiring Trustee or the
Holders of 10% in principal amount of the Notes may petition any court of
competent jurisdiction for the appointment of a successor Trustee.

                  If the Trustee fails to comply with Section 7.10, any Holder
may petition any court of competent jurisdiction for the removal of the Trustee
and the appointment of a successor Trustee.
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                                                                              40


                  Notwithstanding the replacement of the Trustee pursuant to
this Section 7.08, the Issuers' obligations under Section 7.07 shall continue
for the benefit of the retiring Trustee.

                  SECTION 7.09. Successor Trustee by Merger. If the Trustee
consolidates with, merges or converts into, or transfers all or substantially
all its corporate trust business or assets to, another corporation or banking
association, the resulting, surviving or transferee corporation without any
further act shall be the successor Trustee.

                  In case at the time such successor or successors by merger,
conversion or consolidation to the Trustee shall succeed to the trusts created
by this Indenture any of the Notes shall have been authenticated but not
delivered, any such successor to the Trustee may adopt the certificate of
authentication of any predecessor trustee, and deliver such Notes so
authenticated; and in case at that time any of the Notes shall not have been
authenticated, any successor to the Trustee may authenticate such Notes either
in the name of any predecessor hereunder or in the name of the successor to the
Trustee; and in all such cases such certificates shall have the full force which
it is anywhere in the Notes or in this Indenture provided that the certificate
of the Trustee shall have.

                  SECTION 7.10. Eligibility; Disqualification. The Trustee shall
at all times satisfy the requirements of TIA Section 310(a). The Trustee shall
have a combined capital and surplus of at least $50,000,000 as set forth in its
most recent published annual report of condition. The Trustee shall comply with
TIA Section 310(b); provided, however, that there shall be excluded from the
operation of TIA Section 310(b)(1) any indenture or indentures under which other
securities or certificates of interest or participation in other securities of
the Issuers are outstanding if the requirements for such exclusion set forth in
TIA Section 310(b)(1) are met.

                  SECTION 7.11. Preferential Collection of Claims Against
Issuers. The Trustee shall comply with TIA Section 311(a), excluding any
creditor relationship listed in TIA Section 311(b). A Trustee who has resigned
or been removed shall be subject to TIA Section 311(a) to the extent indicated.

                                  ARTICLE VIII

                       Discharge of Indenture; Defeasance

                  SECTION 8.01. Discharge of Liability on Notes; Defeasance. (a)
When (i) either Note Issuer delivers to the Trustee all outstanding Notes (other
than Notes replaced pursuant to Section 2.07) for cancellation or (ii) all
outstanding Notes have become due and payable, whether at maturity or as a
result of the mailing of a notice of redemption pursuant to Article III hereof
and either Note Issuer irrevocably deposits with the Trustee funds or Government
Securities on which payment of principal and interest when due shall be
sufficient to pay at maturity or upon redemption all outstanding Notes,
including interest thereon to maturity or such redemption date (other than Notes
replaced pursuant to Section 2.07), as certified to the Trustee by a nationally
recognized firm of independent accountants, and if in either case the Note
Issuers pay all other sums payable hereunder by the Note Issuers including, but
not limited to fees and expenses of the Trustee and its counsel, then this
Indenture shall, subject to Section 8.01(c), cease to be of further effect. The
Trustee shall acknowledge satisfaction and discharge of this Indenture on demand
of either Note Issuer accompanied by an Officers' Certificate and an Opinion of
Counsel.

                  (b) Subject to Sections 8.01(c), 8.02 and 8.06, the Note
Issuers at any time may terminate (i) all its obligations under the Notes and
this Indenture ("legal defeasance option") or (ii) its obligations under
Sections 4.02, 4.03, 4.04, 4.05, 4.06, 4.07, 4.08, 4.11, 4.12, 4.13, 4.14, 4.15,
4.16, 5.01(a)(ii), 5.01(a)(iii) and 5.01(a)(iv) and the operation of Sections
6.01(4), 6.01(5) (with respect to obligations that have been defeased), 6.01(6),
6.01(7) (with respect to Significant Subsidiaries only), 6.01(8) (with respect
to Significant Subsidiaries only), 6.01(9), 6.01(10), 6.01(11) and 6.01(12)
("covenant defeasance option"). The Note Issuers may exercise their legal
defeasance option notwithstanding their prior exercise of its covenant
defeasance option. If the Note Issuers exercise their legal defeasance option or
their covenant defeasance option, each Guarantor Subsidiary shall be released
from all of its obligations with respect to its Subsidiary Guaranty (and no
Restricted Subsidiary (other than Capital) will thereafter be obligated to
execute, deliver or endorse any Note; nor shall any such execution, delivery or
endorsement thereafter bind any Restricted Subsidiary).

                  If the Note Issuers exercise their legal defeasance option,
payment of the Notes may not be accelerated because of an Event of Default. If
the Note Issuers exercise their covenant defeasance option, payment
   46
                                                                              41


of the Notes may not be accelerated because of an Event of Default specified in
Sections 6.01(4), 6.01(5) (with respect to obligations that have been defeased),
6.01(6), 6.01(7) (with respect to Significant Subsidiaries only), 6.01(8) (with
respect to Significant Subsidiaries only), 6.01(9), 6.01(10), 6.01(11) and
6.01(12) or because of the failure of the Note Issuers to comply with Sections
5.01(a) (ii), 5.01(a) (iii) and 5.01(a) (iv).

                  Upon satisfaction of the conditions set forth herein and upon
request of either Note Issuer, the Trustee shall acknowledge in writing the
discharge of those obligations that have been discharged, released, satisfied or
defeased.

                  (c) Notwithstanding clauses (a) and (b) above, the Note
Issuers' obligations in Sections 2.03, 2.04, 2.05, 2.06, 2.07, 7.07, 7.08, 8.04,
8.05 and 8.06 shall survive until the Notes have been paid in full. Thereafter,
the Note Issuers' obligations in Sections 7.07, 8.04 and 8.05 shall survive.

                  SECTION 8.02. Conditions to Defeasance. The Note Issuers may
exercise their legal defeasance option or its covenant defeasance option only
if:

                  (1) either Note Issuer irrevocably deposits in trust with the
         Trustee money and/or Government Securities for the payment of
         principal, premium and interest on the Notes to maturity or redemption,
         as the case may be;

                  (2) the Note Issuers deliver to the Trustee a certificate from
         a nationally recognized firm of independent accountants expressing
         their opinion that the payments of principal and interest when due and
         without reinvestment on the deposited Government Securities plus any
         deposited money without investment shall provide cash at such times and
         in such amounts as shall be sufficient to pay principal and interest
         when due on all the Notes to maturity or redemption, as the case may
         be;

                  (3) 90 days pass after the deposit is made and during the
         90-day period no Default specified in Section 6.01(7) or 6.01(8) with
         respect to either Note Issuer occurs which is continuing at the end of
         the period;

                  (4) the deposit does not constitute a default under any other
         agreement binding on either Note Issuer;

                  (5) the Note Issuers deliver to the Trustee an Opinion of
         Counsel to the effect that the trust resulting from the deposit does
         not constitute, or is qualified as, a regulated investment company
         under the Investment Company Act of 1940, unless such trust shall be
         registered under and act as exempt from registration thereunder;

                  (6) in the case of the legal defeasance option, the Note
         Issuers shall have delivered to the Trustee an Opinion of Counsel
         stating that (i) the Note Issuers have received from, or there has been
         published by, the Internal Revenue Service a ruling, or (ii) since the
         date of this Indenture there has been a change in the applicable
         federal income tax law, in either case to the effect that, and based
         thereon such Opinion of Counsel shall confirm that, the Holders will
         not recognize income, gain or loss for federal income tax purposes as a
         result of such defeasance and will be subject to federal income tax on
         the same amounts, in the same manner and at the same times as would
         have been the case if such defeasance had not occurred;

                  (7) in the case of the covenant defeasance option, the Note
         Issuers shall have delivered to the Trustee an Opinion of Counsel to
         the effect that the Holders will not recognize income, gain or loss for
         federal income tax purposes as a result of such covenant defeasance and
         will be subject to federal income tax on the same amounts, in the same
         manner and at the same times as would have been the case if such
         covenant defeasance had not occurred; and

                  (8) the Note Issuers delivers to the Trustee an Officers'
         Certificate and an Opinion of Counsel, each stating that all conditions
         precedent to the defeasance and discharge of the Securities as
         contemplated by this Article VIII have been complied with.

                  Anything in this Section 8.02 to the contrary notwithstanding,
the Trustee shall deliver or pay to Iridium from time to time upon the request,
in writing, by either Note Issuer any cash in dollars or Government
   47
                                                                              42


Securities held by it as provided in paragraph (2) above which, in the opinion
of a nationally recognized firm of independent public accountants expressed in a
written certification thereof delivered to the Trustee, are in excess of the
amount thereof which would then be required to be deposited to effect an
equivalent legal defeasance or covenant defeasance.

                  Before or after a deposit, the Note Issuers may make
arrangements satisfactory to the Trustee for the redemption of Notes at a future
date in accordance with Article III.

                  SECTION 8.03. Application of Trust Money. The Trustee shall
hold in trust money or Government Securities deposited with it pursuant to this
Article VIII. It shall apply the deposited money and the money from Government
Securities through the Paying Agent and in accordance with this Indenture to the
payment of principal of and interest on the Notes.

                  SECTION 8.04. Repayment to Note Issuers. The Trustee and the
Paying Agent shall promptly turn over to Iridium upon request any excess money
or securities held by them at any time.

                  Subject to any applicable abandoned property law, the Trustee
and the Paying Agent shall pay to Iridium upon request any money held by them
for the payment of principal or interest that remains unclaimed for two years,
and, thereafter, Holders entitled to the money must look to the Issuers for
payment as general creditors.

                  SECTION 8.05. Indemnity for Government Securities. The Note
Issuers shall pay and shall indemnify the Trustee against any tax, fee or other
charge imposed on or assessed against deposited Government Securities or the
principal and interest received on such Government Securities other than any
tax, fee or other charge which by law is for the account of the Holders.

                  SECTION 8.06. Reinstatement. If the Trustee or Paying Agent is
unable to apply any money or Government Securities in accordance with this
Article VIII by reason of any legal proceeding or by reason of any order or
judgment of any court or governmental authority enjoining, restraining or
otherwise prohibiting such application, the Note Issuers' obligations under this
Indenture and the Notes shall be revived and reinstated as though no deposit had
occurred pursuant to this Article VIII until such time as the Trustee or Paying
Agent is permitted to apply all such money or Government Securities in
accordance with this Article VIII; provided, however, that, if the Note Issuers
have made any payment of interest on or principal of any Notes because of the
reinstatement of its obligations, the Note Issuers shall be subrogated to the
rights of the Holders of such Notes to receive such payment from the money or
Government Securities held by the Trustee or Paying Agent.

                                   ARTICLE IX

                                   Amendments

                  SECTION 9.01. Without Consent of Holders. The Note Issuers,
the Guarantor Subsidiaries and the Trustee may amend this Indenture or the
Securities without notice to or consent of any Holder:

                  (1) to cure any ambiguity, omission, defect or inconsistency;

                  (2) to comply with Section 4.15 or Article V;

                  (3) to provide for uncertificated Securities in addition to or
         in place of Notes; provided, however, that the uncertificated Notes are
         issued in registered form for purposes of Section 163(f) of the Code or
         in a manner such that the uncertificated Notes are described in Section
         163(f)(2)(B) of the Code;

                  (4) to add further Subsidiary Guaranties with respect to the
         Notes or to release Guarantor Subsidiaries when permitted by the terms
         hereof, or to secure the Notes;

                  (5) to add to the covenants of the Note Issuers for the
         benefit of the Holders or to surrender any right or power herein
         conferred upon the Note Issuers;
   48
                                                                              43


                  (6) to comply with any requirements of the SEC in connection
         with qualifying this Indenture under the TIA; and

                  (7) to make any change that does not adversely affect the
         rights of any Holder.

                  After an amendment under this Section 9.01 becomes effective,
the Note Issuers shall mail to Holders a notice briefly describing such
amendment. The failure to give such notice to all Holders, or any defect
therein, shall not impair or affect the validity of an amendment under this
Section 9.01.

                  SECTION 9.02. With Consent of Holders. The Note Issuers, the
Guarantor Subsidiaries and the Trustee may amend this Indenture or the Notes
without notice to any Holder but with the written consent of the Holders of at
least a majority in principal amount of the Notes. The Holders of at least a
majority in principal amount of the Notes may waive compliance by the Note
Issuers or any Guarantor Subsidiary with any provision or covenant of this
Indenture or the Notes. However, without the consent of each Holder of an
outstanding Note, an amendment or waiver may not:

                  (1) reduce the amount of Notes whose Holders must consent to
         an amendment or waiver;

                  (2) reduce the rate of or extend the time for payment of
         interest on any such Note;

                  (3) reduce the principal of or extend the Stated Maturity of
         any such Note;

                  (4) reduce the premium payable upon the redemption of any Note
         or change the time at which any Note may be redeemed in accordance with
         Article III;

                  (5) make any Note payable in money other than that stated in
         such Note;

                  (6) impair the right of any Holder to receive payment of
         principal of and premium and interest on such Holder's Notes on or
         after the due dates therefor or to institute suit for the enforcement
         of any payment on or with respect to such Holder's Notes;

                  (7) modify the Subsidiary Guaranties (except as contemplated
         by the terms thereof or of this Indenture) in any manner adverse to the
         Holders; or

                  (8) make any change in Section 6.04, Section 6.07 or the third
         sentence of this Section 9.02.

                  It shall not be necessary for the consent of the Holders under
this Section to approve the particular form of any proposed amendment, but it
shall be sufficient if such consent approves the substance thereof.

                  After an amendment under this Section 9.02 becomes effective,
the Note Issuers shall mail to Holders a notice briefly describing such
amendment. The failure to give such notice to all Holders, or any defect
therein, shall not impair or affect the validity of an amendment under this
Section 9.02.

                  SECTION 9.03. Compliance with Trust Indenture Act. Every
amendment to this Indenture or the Notes shall comply with the TIA as then in
effect.

                  SECTION 9.04. Revocation and Effect of Consents and Waivers. A
consent to an amendment or a waiver by a Holder of a Note shall bind the Holder
and every subsequent Holder of that Note or portion of the Note that evidences
the same debt as the consenting Holder's Note, even if notation of the consent
or waiver is not made on the Note. However, any such Holder or subsequent Holder
may revoke the consent or waiver as to such Holder's Note or portion of the Note
if the Trustee receives the notice of revocation before the date the amendment
or waiver becomes effective. After an amendment or waiver becomes effective, it
shall bind every Holder. An amendment or waiver becomes effective once the
consents from the Holders of the requisite percentage in principal amount of
outstanding Notes are received by the Notes Issuers or the Trustee.

                  The Note Issuers may, but shall not be obligated to, fix a
record date for the purpose of determining the Holders entitled to give their
consent or take any other action described above or required or permitted to be
taken pursuant to this Indenture. If a record date is fixed, then
notwithstanding the immediately
   49
                                                                              44


preceding paragraph, those Persons who were Holders at such record date (or
their duly designated proxies), and only those Persons, shall be entitled to
give such consent or to revoke any consent previously given or to take any such
action, whether or not such Persons continue to be Holders after such record
date. No such consent shall be valid or effective for more than 120 days after
such record date.

                  SECTION 9.05. Notation on or Exchange of Notes. If an
amendment changes the terms of a Note, the Trustee may require the Holder of the
Note to deliver it to the Trustee. The Trustee may place an appropriate notation
on the Note regarding the changed terms and return it to the Holder.
Alternatively, if the Note Issuers or the Trustee so determines, the Note
Issuers in exchange for the Note shall issue and the Trustee shall authenticate
a new Note that reflects the changed terms. Failure to make the appropriate
notation or to issue a new Note shall not affect the validity of such amendment.

                  SECTION 9.06. Trustee To Sign Amendments. The Trustee shall
sign any amendment authorized pursuant to this Article IX if the amendment does
not adversely affect the rights, duties, liabilities or immunities of the
Trustee. If it does, the Trustee may but need not sign it. In signing any
amendment the Trustee shall be entitled to receive indemnity reasonably
satisfactory to it and to receive, and (subject to Section 7.01) shall be fully
protected in relying upon, an Officers' Certificate and an Opinion of Counsel
stating that such amendment is authorized or permitted by this Indenture and
complies with the provisions hereof (including Section 9.03).

                                    ARTICLE X

                              Subsidiary Guarantees

                  SECTION 10.01. Subsidiary Guarantees. Each Guarantor
Subsidiary hereby jointly and severally unconditionally and irrevocably
guarantees, as a primary obligor and not merely as a surety, to each Holder and
to the Trustee and its successors and assigns (a) the full and punctual payment
of principal of and interest on the Notes when due, whether at maturity, by
acceleration, by redemption or otherwise, and all other monetary obligations of
the Note Issuers under this Indenture (including obligations to the Trustee) and
the Notes and (b) the full and punctual performance within applicable grace
periods of all other obligations of the Issuers whether for expenses,
indemnification or otherwise under this Indenture and the Notes (all the
foregoing being hereinafter collectively called the "Obligations"). Each
Guarantor Subsidiary further agrees that the Obligations may be extended or
renewed, in whole or in part, without notice or further assent from each such
Guarantor Subsidiary, and that each such Guarantor Subsidiary shall remain bound
under this Article X notwithstanding any extension or renewal of any Obligation.

                  Each Guarantor Subsidiary waives presentation to, demand of,
payment from and protest to the Note Issuers of any of the Obligations and also
waives notice of protest for nonpayment. Each Guarantor Subsidiary waives notice
of any default under the Notes or the Obligations. The obligations of each
Guarantor Subsidiary hereunder shall not be affected by (a) the failure of any
Holder or the Trustee to assert any claim or demand or to enforce any right or
remedy against the Note Issuers or any other Person under this Indenture, the
Notes or any other agreement or otherwise; (b) any extension or renewal of any
thereof; (c) any rescission, waiver, amendment or modification of any of the
terms or provisions of this Indenture, the Notes or any other agreement; (d) the
release of any security held by any Holder or the Trustee for the Obligations or
any of them; (e) the failure of any Holder or Trustee to exercise any right or
remedy against any other guarantor of the Obligations; or (f) any change in the
ownership of such Guarantor Subsidiary, except as provided in Section 10.02(b).

                  Each Guarantor Subsidiary further agrees that its Subsidiary
Guaranty herein constitutes a guarantee of payment, performance and compliance
when due (and not a guarantee of collection) and waives any right to require
that any resort be had by any Holder or the Trustee to any security held for
payment of the Obligations.

                  The obligations of each Guarantor Subsidiary hereunder shall
not be subject to any reduction, limitation, impairment or termination for any
reason (except based on actual payment or performance or any release or
termination contemplated by this Indenture), including any claim of waiver,
release, surrender, alteration or compromise, and shall not be subject to any
defense of setoff, counterclaim, recoupment or termination whatsoever or by
reason of the invalidity, illegality or unenforceability of the Obligations or
otherwise. Without limiting the generality of the foregoing, the obligations of
each Guarantor Subsidiary herein shall not be discharged or impaired
   50
                                                                              45


or otherwise affected by the failure of any Holder or the Trustee to assert any
claim or demand or to enforce any remedy under this Indenture, the Notes or any
other agreement, by any waiver or modification of any thereof, by any default,
failure or delay, willful or otherwise, in the performance of the Obligations,
or by any other act or thing or omission or delay to do any other act or thing
which may or might in any manner or to any extent vary the risk of, or would
otherwise operate as a discharge of, a surety as a matter of law or equity.

                  Each Guarantor Subsidiary further agrees that its Subsidiary
Guaranty herein shall continue to be effective or be reinstated, as the case may
be, if at any time payment, or any part thereof, of principal of or interest on
any Obligation is rescinded or must otherwise be restored by any Holder or the
Trustee upon the bankruptcy or reorganization of the Note Issuers or otherwise.

                  In furtherance of the foregoing and not in limitation of any
other right which any Holder or the Trustee has at law or in equity against any
Guarantor Subsidiary by virtue hereof, upon the failure of the Note Issuers to
pay the principal of or interest on any Obligation when and as the same shall
become due, whether at maturity, by acceleration, by redemption or otherwise, or
to perform or comply with any other Obligation, each Guarantor Subsidiary hereby
promises to and shall, upon receipt of written demand by the Trustee, forthwith
pay, or cause to be paid, in cash, to the Holders or the Trustee an amount equal
to the sum of (i) the unpaid principal amount of such Obligations, (ii) accrued
and unpaid interest on such Obligations (but only to the extent not prohibited
by law) and (iii) all other monetary Obligations of the Note Issuers to the
Holders and the Trustee.

                  Each Guarantor Subsidiary agrees that it shall not be entitled
to any right of subrogation in relation to the Holders in respect of any
Obligations guaranteed hereby until payment in full of all Obligations. Each
Guarantor Subsidiary further agrees that, as between it, on the one hand, and
the Holders and the Trustee, on the other hand, (x) the maturity of the
Obligations guaranteed hereby may be accelerated as provided in Article VI for
the purposes of any Subsidiary Guaranty herein, notwithstanding any stay,
injunction or other prohibition preventing such acceleration in respect of the
Obligations guaranteed hereby, and (y) in the event of any declaration of
acceleration of such Obligations as provided in Article VI, such Obligations
(whether or not due and payable) shall forthwith become due and payable by such
Guarantor Subsidiary for the purposes of this Section 10.01.

                  Each Guarantor Subsidiary also agrees to pay any and all costs
and expenses (including reasonable attorneys' fees and expenses) incurred by the
Trustee or any Holder in enforcing any rights under this Section 10.01.

                  SECTION 10.02. Limitation on Liability. (a) Any term or
provision of this Indenture to the contrary notwithstanding, the maximum,
aggregate amount of the obligations guaranteed hereunder by any Guarantor
Subsidiary shall not exceed the maximum amount that can be hereby guaranteed
without rendering this Indenture, as it relates to any Guarantor Subsidiary,
voidable under applicable law relating to fraudulent conveyance or fraudulent
transfer or similar laws affecting the rights of creditors generally.

                  (b) This Subsidiary Guaranty as to any Guarantor Subsidiary
shall terminate and be of no further force or effect and such Guarantor
Subsidiary shall be released from its obligations in respect of this Subsidiary
Guaranty upon (i) the sale or other transfer (x) by such Guarantor Subsidiary of
all or substantially all of its assets or (y) of all of the Capital Stock of
such Guarantor Subsidiary, to a Person other than Iridium or a Subsidiary of
Iridium; provided, however, that such sale or transfer shall be deemed to
constitute an Asset Disposition and the Note Issuers shall comply with its
obligations under Section 4.06; (ii) the designation by Iridium of such
Guarantor Subsidiary as an Unrestricted Subsidiary in accordance with this
Indenture; (iii) reorganization of such Guarantor Subsidiary as a Foreign
Subsidiary; or (iv) upon satisfaction of the requirements of Section 5.01(c) or
8.01(b), as the case may be, that would permit such a release.

                  SECTION 10.03. Successors and Assigns. This Article X shall be
binding upon each Guarantor Subsidiary and its successors and assigns and shall
enure to the benefit of the successors and assigns of the Trustee and the
Holders and, in the event of any transfer or assignment of rights by any Holder
or the Trustee, the rights and privileges conferred upon that party in this
Indenture and in the Notes shall automatically extend to and be vested in such
transferee or assignee, all subject to the terms and conditions of this
Indenture.

                  SECTION 10.04. No Waiver. Neither a failure nor a delay on the
part of either the Trustee or the Holders in exercising any right, power or
privilege under this Article X shall operate as a waiver thereof, nor shall a
single or partial exercise thereof preclude any other or further exercise of any
right, power or privilege. The rights, remedies and benefits of the Trustee and
the Holders herein expressly specified are cumulative and not exclusive of
   51
                                                                              46


any other rights, remedies or benefits which either may have under this Article
X at law, in equity, by statute or otherwise.

                  SECTION 10.05. Modification. No modification, amendment or
waiver of any provision of this Article X, nor the consent to any departure by
any Guarantor Subsidiary therefrom, shall in any event be effective unless the
same shall be in writing and signed by the Trustee, and then such waiver or
consent shall be effective only in the specific instance and for the purpose for
which given. No notice to or demand on any Guarantor Subsidiary in any case
shall entitle such Guarantor Subsidiary to any other or further notice or demand
in the same, similar or other circumstances.

                  SECTION 10.06. Initial Guarantors; Execution of Supplemental
Indenture for Future Guarantor Subsidiaries. Each Restricted Subsidiary which is
required to become, or is designated by Iridium to become, a Guarantor
Subsidiary pursuant to Section 4.15 shall promptly execute and deliver to the
Trustee a supplemental indenture in the form of Exhibit B hereto pursuant to
which such Subsidiary shall become a Guarantor Subsidiary under this Article X
and shall guarantee the Obligations. Concurrently with the execution and
delivery of such supplemental indenture, the Note Issuers shall deliver to the
Trustee an Opinion of Counsel and an Officers' Certificate to the effect that
such supplemental indenture has been duly authorized, executed and delivered by
such Subsidiary and that, subject to the application of bankruptcy, insolvency,
moratorium, fraudulent conveyance or transfer and other similar laws relating to
creditors' rights generally and to the principles of equity, whether considered
in a proceeding at law or in equity, the Subsidiary Guaranty of such Guarantor
Subsidiary is a legal, valid and binding obligation of such Guarantor
Subsidiary, enforceable against such Guarantor Subsidiary in accordance with its
terms.

                                   ARTICLE XI

                                  Miscellaneous

                  SECTION 11.01. Trust Indenture Act Controls. If any provision
of this Indenture limits, qualifies or conflicts with another provision which is
required to be included in this Indenture by the TIA, the required provision
shall control.

                  SECTION 11.02. Notices. Any notice or communication shall be
in writing and delivered in person or mailed by first-class mail or by national
overnight courier service addressed as follows:

                            if to any of the Issuers:

                            c/o Iridium Operating LLC
                              1575 Eye Street, N.W.
                              Washington, DC 20006
                           Attention: General Counsel
                            Facsimile: (202) 408-3761

                               if to the Trustee:

                       State Street Bank and Trust Company
                           Corporate Services Division
                                    4th Floor
                              2 International Place
                                Boston, MA 02110
                           Attention: Mr. Shawn George
                            Facsimile: (617) 664-5371

                  The Issuers or the Trustee by notice to the others may
designate additional or different addresses for subsequent notices or
communications.
   52
                                                                              47


                  Any notice or communication mailed to a Holder shall be mailed
to the Holder at such Holder's address as it appears on the registration books
of the Registrar and shall be sufficiently given if so mailed by first class
mail within the time prescribed.

                  Failure to mail a notice or communication to a Holder or any
defect in it shall not affect its sufficiency with respect to other Holders. If
a notice or communication is mailed in the manner provided above, it is duly
given, whether or not the addressee receives it, except that any such notice to
the Trustee must be received by a Trust Officer to be duly given.

                  Where this Indenture provides for notice in any manner, such
notice may be waived in writing by the Person entitled to receive such notice,
either before or after the event, and such waiver shall be the equivalent of
such notice.

                  SECTION 11.03. Communication by Holders with Other Holders.
Holders may communicate pursuant to TIA Section 312(b) with other Holders with
respect to their rights under this Indenture or the Notes. The Issuers, the
Trustee, the Registrar and anyone else shall have the protection of TIA
Section 312(c).

                  SECTION 11.04. Certificate and Opinion as to Conditions
Precedent. Upon any request or application by the Issuers to the Trustee to take
or refrain from taking any action under this Indenture, the Note Issuers shall,
if requested by the Trustee, furnish to the Trustee:

                  (1) an Officers' Certificate in form and substance reasonably
         satisfactory to the Trustee and complying with Section 11.05 stating
         that, in the opinion of the signers, all conditions precedent, if any,
         provided for in this Indenture relating to the proposed action have
         been complied with; and

                  (2) an Opinion of Counsel in form and substance reasonably
         satisfactory to the Trustee and complying with Section 11.05 stating
         that, in the opinion of such counsel, all such conditions precedent
         have been complied with.

                  SECTION 11.05. Statements Required in Certificate or Opinion.
Each certificate or opinion with respect to compliance with a covenant or
condition provided for in this Indenture shall include:

                  (1) a statement that the individual making such certificate or
         opinion has read such covenant or condition;

                  (2) a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate or opinion are based;

                  (3) a statement that, in the opinion of such individual, he
         has made such examination or investigation as is necessary to enable
         him to express an informed opinion as to whether or not such covenant
         or condition has been complied with; and

                  (4) a statement as to whether or not, in the opinion of such
         individual, such covenant or condition has been complied with.

                  SECTION 11.06. When Notes Disregarded. In determining whether
the Holders of the required principal amount of Notes have concurred in any
direction, waiver or consent, Notes owned by the Issuers or by any Person
directly or indirectly controlling or controlled by or under direct or indirect
common control with the Issuers shall be disregarded and deemed not to be
outstanding, except that, for the purpose of determining whether the Trustee
shall be protected in relying on any such direction, waiver or consent, only
Notes which the Trustee knows are so owned shall be so disregarded. Also,
subject to the foregoing, only Notes outstanding at the time shall be considered
in any such determination.

                  SECTION 11.07. Rules by Trustee Paying Agent and Registrar.
The Trustee may make reasonable rules for action by or a meeting of Holders. The
Registrar and the Paying Agent may make reasonable rules for their functions.
   53
                                                                              48


                  SECTION 11.08. Legal Holidays. If a payment date is not a
Business Day, payment shall be made on the next succeeding day that is a
Business Day, and no interest shall accrue for the intervening period. If a
regular record date is not a Business Day, the record date shall not be
affected.

                  SECTION 11.09. Governing Law. THIS INDENTURE AND THE NOTES
SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF
NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW
TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE
REQUIRED THEREBY.

                  SECTION 11.10. No Recourse Against Others. A director,
officer, employee, incorporator or member or stockholder, as such, of Iridium
shall not have any liability for any obligations of any Issuer under the Notes
or this Indenture or for any claim based on, in respect of or by reason of such
obligations or their creation. By accepting a Note, each Holder shall waive and
release all such liability. The waiver and release shall be part of the
consideration for the issue of the Notes. Such waiver will not constitute a
waiver of liabilities under the federal securities laws if it is the view of the
SEC that such a waiver would be against public policy.

                  SECTION 11.11. Successors. All agreements of the Issuers in
this Indenture and the Notes shall bind their successors. All agreements of the
Trustee in this Indenture shall bind its successors.

                  SECTION 11.12. Multiple Originals. The parties may sign any
number of copies of this Indenture. Each signed copy shall be an original, but
all of them together represent the same agreement. One signed copy is enough to
prove this Indenture.

                  SECTION 11.13. Table of Contents; Headings. The table of
contents, cross-reference sheet and headings of the Articles and Sections of
this Indenture have been inserted for convenience of reference only, are not
intended to be considered a part hereof and shall not modify or restrict any of
the terms or provisions hereof.
   54
                                                                              49


                  IN WITNESS WHEREOF, the parties have caused this Indenture to
be duly executed as of the date first written above.

                                             IRIDIUM OPERATING LLC

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

                                             IRIDIUM CAPITAL CORPORATION

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

                                             IRIDIUM ROAMING LLC

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

                                             IRIDIUM IP LLC

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

                                             IRIDIUM FACILITIES CORPORATION

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

                                             STATE STREET BANK AND TRUST
                                               COMPANY, as Trustee

                                             By:
                                                 -------------------------------
                                                 Name:
                                                 Title:
   55
                                                                       EXHIBIT A

                              FORM OF FACE OF NOTE

                  UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"),
TO THE ISSUERS OR THEIR AGENTS FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR
SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC) ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED
OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.(1)

                  TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO
TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR
THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL
SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS
SET FORTH IN THE INDENTURE REFERRED TO HEREIN.(1)

                              IRIDIUM OPERATING LLC
                           IRIDIUM CAPITAL CORPORATION

                      _____% SENIOR NOTE DUE 2005, SERIES D

No.                                                         CUSIP No. [        ]
                                                                     $[        ]

                  IRIDIUM OPERATING LLC, a Delaware limited liability
corporation and IRIDIUM CAPITAL CORPORATION, a Delaware corporation, as joint
and several obligors, promise to pay to [ ], or registered assigns, the
principal sum of $[ ] on July 15, 2005.

                  Interest Payment Dates:            January 15 and July 15

                  Record Dates:                      January 1 and July 1

- ----------

1        These paragraphs should only be added if the Security is issued in
         global form.
   56
                                                                               2


                  Additional provisions of this Note are set forth on the other
side of this Note.

Dated:

                                             IRIDIUM OPERATING LLC

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

                                             IRIDIUM CAPITAL CORPORATION

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

TRUSTEE'S CERTIFICATE OF
    AUTHENTICATION

STATE STREET BANK AND
    TRUST COMPANY

as Trustee, certifies
that this is one of
the Notes referred
to in the Indenture,


By:
    -------------------------------
         Authorized Signatory
   57
                                                                               3


                                             Guaranteed pursuant to the
                                             Indenture:

                                             IRIDIUM ROAMING LLC

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

                                             IRIDIUM IP LLC

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

                                             IRIDIUM FACILITIES CORPORATION

                                             By:
                                                 -------------------------------
                                                 Name:
                                                 Title:
   58
                                                                               4


                          FORM OF REVERSE SIDE OF NOTE

                      ____% Senior Note due 2005, Series D

1.       Interest.

                  IRIDIUM OPERATING LLC, a Delaware limited liability company
("Iridium") and IRIDIUM CAPITAL CORPORATION, a Delaware corporation ("Capital"
and together with Iridium, the "Note Issuers"), as joint and several obligors,
and IRIDIUM ROAMING LLC, IRIDIUM IP LLC and IRIDIUM FACILITIES CORPORATION
(together, the "Guarantor Subsidiaries", and together with the Note Issuers, the
"Issuers"), promise to pay interest on the principal amount of the Notes at the
rate per annum shown above. Iridium will pay interest in cash semi-annually in
arrears on January 15 and July 15 of each year (each an "Interest Payment
Date"), commencing July 15, 1998. Interest payable on the Notes shall be
computed on the basis of a 360-day year comprised of 30-day months.

2.       Method of Payment.

                  The Note Issuers shall pay interest on the Notes (except
defaulted interest) to the persons who are the registered holders at the close
of business on the Record Date immediately preceding the interest payment date
even if the Notes are cancelled on registration of transfer or registration of
exchange after such Record Date. Holders must surrender the Notes to the Trustee
to collect principal payments. The Note Issuers shall pay principal and interest
in money of the United States that at the time of payment is legal tender for
payment of public and private debts ("U.S. Legal Tender"). However, the Note
Issuers may pay principal and interest by wire transfer of Federal funds, or
interest by check payable in such U.S. Legal Tender. The Note Issuers may
deliver any such interest payment to the Trustee or to a holder at the holder's
registered address.

3.       Paying Agent and Registrar.

                  Initially, STATE STREET BANK AND TRUST COMPANY, a
Massachusetts banking corporation ("Trustee"), will act as Paying Agent and
Registrar. Iridium may appoint and change any Paying Agent, Registrar or
co-registrar without notice to the Holders. Iridium, Capital or any of Iridium's
domestically incorporated Wholly-Owned Subsidiaries may not act as Paying Agent,
Registrar or co-registrar.

4.       Indenture and Guarantees.

                  The Note Issuers issued the Notes under an Indenture dated as
of _______, 1998 (the "Indenture"), among the Note Issuers, as joint and several
obligors, the Guarantor Subsidiaries (as defined in the Indenture) and the
Trustee. Capitalized terms used herein are used as defined in the Indenture
unless otherwise defined herein. The terms of the Notes include those stated in
the Indenture and those made part of such Indenture by reference to the Trust
Indenture Act of 1939 (15 U.S.C. Sections 77aaa-77bbbb) (the "TIA"), as in
effect on the date of the Indenture until such time as the Indenture is
qualified under the TIA, and thereafter as in effect on the date on which the
Indenture is qualified under the TIA. Notwithstanding anything to the contrary
herein, the Notes are subject to all such terms, and holders of Notes are
referred to the Indenture and the TIA for a statement of them. The Notes are
obligations of the Note Issuers limited in aggregate principal amount to
$350,000,000. Payment on each Note is guaranteed on a senior basis, jointly and
severally, by the Guarantor Subsidiaries pursuant to Article X of the Indenture.
   59
                                                                               5


5.       Optional Redemption.

                  Except as described in the next succeeding paragraph, the
Notes will not be redeemable at the option of the Note Issuers prior to July 15,
2002. On and after such date, the Notes will be redeemable, at either Note
Issuer's option, in whole or in part, at any time upon not less than 30 nor more
than 60 days' prior notice mailed by first-class mail to each Holder's
registered address, at the following redemption prices (expressed in percentages
of principal amount), plus accrued and unpaid interest to the redemption date
(subject to the right of Holders of record on the relevant record date to
receive interest due on the relevant interest payment date that is on or prior
to the date of redemption), if redeemed during the 12-month period commencing on
July 15 of the years set forth below:



                                                                       Redemption
Year                                                                     Price
                                                                    
2002                                                                           %
2003                                                                           %
2004 and thereafter                                                     100.000%


                  In addition, at any time and from time to time on or prior to
July 15, 2000, either Note Issuer may redeem in the aggregate up to 33-1/3% of
the original aggregate principal amount of the Notes with the cash proceeds to
Iridium of one or more Equity Offerings, at a redemption price (expressed as a
percentage of principal amount thereof) of ______% plus accrued and unpaid
interest to the redemption date (subject to the right of Holders of record on
the relevant record date to receive interest due on the relevant interest
payment date that is on or prior to the date of redemption); provided, however,
that at least 66-2/3% of the original aggregate principal amount of the Notes
must remain outstanding after each such redemption.

6.       Notice of Redemption.

                  In the case of any partial redemption, selection of the Notes
for redemption will be made by the Trustee on a pro rata basis, by lot or by
such other method as the Trustee in its sole discretion deems to be fair and
appropriate, although no Note of $1,000 in original principal amount or less
will be redeemed in part. If any Note is to be redeemed in part only, the notice
of redemption relating to such Note will state the portion of the principal
amount thereof to be redeemed. A new Note in principal amount equal to the
unredeemed portion thereof will be issued in the name of the Holder thereof upon
cancellation of the original Note.

7.       Subsidiary Guaranties.

                  The Initial Guarantors will provide Subsidiary Guaranties on
the Issue Date. In the event that, after the Issue Date, Iridium acquires or
creates a Subsidiary other than a Foreign Subsidiary, Iridium will cause such
Subsidiary (unless such Subsidiary is an Unrestricted Subsidiary) to, jointly
and severally, as primary obligors and not merely as sureties, irrevocably
Guarantee on a senior unsecured basis the performance and punctual payment when
due, whether at Stated Maturity, by acceleration or otherwise, of all
obligations of the Note Issuers under the Indenture and the Notes issued
pursuant thereto. Iridium may cause any Foreign Subsidiary to execute and
deliver a Subsidiary Guaranty in accordance with the provisions of the
Indenture, in which case such Foreign Subsidiary will be a "Guarantor
Subsidiary" for purposes of the Indenture. Each Subsidiary Guaranty will be
limited in amount to an amount not to exceed the maximum amount that can be
Guaranteed by the applicable Guarantor Subsidiary without rendering such
Subsidiary Guaranty voidable under applicable law relating to fraudulent
conveyance or fraudulent transfer or similar laws affecting the rights of
creditors generally.

                  A Subsidiary Guaranty will be released upon (i) the sale of
all of the Capital Stock, or all or substantially all of the assets, of the
applicable Guarantor Subsidiary (in each case to an entity other than to Iridium
or a Subsidiary of Iridium), (ii) the designation by Iridium of the applicable
Guarantor Subsidiary as an Unrestricted Subsidiary, in each case in compliance
with the Indenture, (iii) the reorganization of the applicable Guarantor
Subsidiary as a Foreign Subsidiary, or (iv) upon satisfaction of the
requirements of Section 5.01(d) (merger) or 8.01(b) (defeasance) of the
Indenture.
   60
                                                                               6


8.       Change of Control Offer.

                  Upon the occurrence of a Change of Control, each Holder will
have the right to require the Note Issuers to repurchase all or any part of such
Holder's Notes at a purchase price in cash equal to 101% of the principal amount
of the Notes, plus accrued and unpaid interest to the date of purchase.

9.       Denominations; Transfer; Exchange.

                  The Notes are in registered form without coupons in
denominations of $1,000 and whole multiples of $1,000. A Holder may transfer or
exchange Notes in accordance with the Indenture. Upon any transfer or exchange,
the Registrar and the Trustee may require a Holder, among other things, to
furnish appropriate endorsements or transfer documents and to pay any taxes
required by law or permitted by the Indenture. The Registrar need not register
the transfer of or exchange any Notes selected for redemption (except, in the
case of a Note to be redeemed in part, the portion of the Note not to be
redeemed) or to transfer or exchange any Notes for a period of 15 days prior to
a selection of Notes to be redeemed or 15 days before an interest payment date.

10.      Persons Deemed Owners.

                  The registered Holder of this Note may be treated as the owner
of it for all purposes.

11.      Unclaimed Money.

                  If money for the payment of principal or interest remains
unclaimed for two years, the Trustee or Paying Agent shall, subject to the
requirements of applicable escheat laws, pay the money back to the Note Issuers
at its written request unless an abandoned property law designates another
Person. After any such payment, Holders entitled to the money must look only to
the Note Issuers and not to the Trustee for payment.

12.      Legal Defeasance and Covenant Defeasance.

                  The Note Issuers at any time may terminate all their
obligations under the Notes and the Indenture upon satisfaction of certain
conditions specified in the Indenture, except for certain obligations, including
those respecting the defeasance trust and obligations to register the transfer
or exchange of the Notes, to replace mutilated, destroyed, lost or stolen Notes
and to maintain a registrar and paying agent in respect of the Notes. The Note
Issuers at any time may terminate their obligations under certain restrictive
covenants. If the Note Issuers exercise their legal defeasance option or their
covenant defeasance option, each Guarantor Subsidiary will be released from all
of its obligations with respect to its Subsidiary Guaranty (and no Restricted
Subsidiary (other than Capital) will thereafter be obligated to execute,
deliver, or endorse any Note; nor shall any such execution, delivery or
endorsement thereafter bind any Restricted Subsidiary).

13.      Amendment and Waiver.

                  Subject to certain exceptions, the Indenture may be amended
with the consent of the Holders of a majority in principal amount of the Notes
then outstanding and any past default and its consequences or compliance with
any provisions may be waived with the consent of the Holders of a majority in
principal amount of the Notes then outstanding. Without the consent of any
Holder, the Note Issuers and the Trustee may amend the Indenture to cure any
ambiguity, omission, defect or inconsistency, to provide for the assumption by a
successor corporation of the obligations of either Note Issuer under the
Indenture, to provide for uncertificated Notes in addition to or in place of
certificated Notes, to add further Subsidiary Guaranties with respect to such
Notes, to release Guarantor Subsidiaries when permitted by such Indenture, to
secure such Notes, to add to the covenants of the Note Issuers for the benefit
of the Holders of such Notes or to surrender any right or power conferred upon
the Note Issuers, to make any change that does not adversely affect the rights
of any Holder of such Notes or to comply with any requirement of the SEC in
connection with the qualification of such Indenture under the TIA.
   61
                                                                               7


14.      Restrictive Covenants.

                  The Indenture contains certain covenants that, among other
things, limit the ability of Iridium and its Restricted Subsidiaries to make
restricted payments, to incur indebtedness, to create liens, to issue capital
stock of subsidiaries, to sell assets, to permit restrictions on dividends and
other payments by subsidiaries to Iridium, to consolidate, merge or sell all or
substantially all of its assets, to engage in transactions with affiliates, to
maintain insurance or to engage in certain businesses. The limitations are
subject to a number of important qualifications and exceptions. The Note Issuers
must report to the Trustee on compliance with such limitations.

15.      Defaults and Remedies.

                  If an Event of Default under the Indenture occurs and is
continuing, the Trustee or the Holders of at least 25% in principal amount of
the outstanding Notes by notice to the Note Issuers and the Trustee in writing
may declare the principal of and accrued but unpaid interest on all the Notes to
be due and payable. If an Event of Default relating to certain events of
bankruptcy, insolvency or reorganization of either Note Issuer occurs and is
continuing, the principal of and interest on all the Notes will become
immediately due and payable without any declaration or other act on the part of
the Trustee or any Holders. Holders of Notes may not enforce the Indenture or
the Notes except as provided in the Indenture. Under certain circumstances, the
Holders of a majority in principal amount of the Notes then outstanding may
rescind any such acceleration with respect to the Notes and its consequences.

16.      No Recourse Against Others.

                  No director, officer, employee, incorporator or member of
Iridium, as such, will have any liability for any obligations of the Note
Issuers or any Guarantor Subsidiary under the Notes or the Indenture or for any
claim based on, in respect of, or by reason of, such obligations or their
creation. Each Holder of Notes by accepting a Note waives and releases all such
liability (such waiver will not constitute a waiver of liabilities under the
Federal securities laws, however, if it is the view of the SEC that such a
waiver would be against public policy).

17.      Trustee Dealings with the Note Issuers.

                  Subject to certain limitations imposed by the Act, the Trustee
under the Indenture, in its individual or any other capacity, may become the
owner or pledgee of Notes and may otherwise deal with and collect obligations
owed to it by the Note Issuers or its Affiliates and may otherwise deal with the
Note Issuers or its Affiliates with the same rights it would have if it were not
Trustee.

18.      Governing Law.

                  THE NOTES SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE
WITH, THE LAWS OF THE STATE OF NEW YORK, BUT WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF
ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

19.      Authentication.

                  This Note shall not be valid until an authorized signatory of
the Trustee (or an authenticating agent) manually signs the certificate of
authentication on the other side of this Note.


20.      Abbreviations.

                  Customary abbreviations may be used in the name of a Holder or
an assignee, such as TEN COM (=tenants in common), TEN ENT (=tenants by the
entireties), JT TEN (=joint tenants with rights of survivorship and not as
tenants in common), CUST (=custodian), and U/G/M/A (=Uniform Gift to Minors
Act).

21.      CUSIP Numbers.
   62
                                                                               8


                  Pursuant to a recommendation promulgated by the Committee on
Uniform Security Identification Procedures the Note Issuers have caused CUSIP
numbers to be printed on the Notes and has directed the Trustee to use CUSIP
numbers in notices of redemption as a convenience to Holders. No representation
is made as to the accuracy of such numbers either as printed on the Notes or as
contained in any notice of redemption and reliance may be placed only on the
other identification numbers placed thereon.

                  The Note Issuers will furnish to any Holder upon written
request and without charge to the Holder a copy of the Indenture which has in it
the text of this Note in larger type. Requests may be made to:

                                   IRIDIUM LLC
                              1575 Eye Street, N.W.
                              Washington, DC 20006
                           Attention: General Counsel
   63
                                                                               9


                                 ASSIGNMENT FORM

To assign this Security, fill in the form below:

I or we assign and transfer this Note to

         (Print or type assignee's name, address and zip code)

         (Insert assignee's soc. sec. or tax I.D. No.)

and irrevocably appoint                            agent to
transfer this Note on the books of the Note Issuers. The agent may substitute
another to act for him.

________________________________________

Date: _______________ Your Signature: ______________________________

Signature Guarantee: _______________________________________
                      (Signature must be guaranteed by a
                       participant in a recognized signature
                       guarantee medallion program)

_____________________________________________________________________
Sign exactly as your name appears on the other side of this Security.
   64
                                                                              10


              SCHEDULE OF INCREASES OR DECREASES IN GLOBAL NOTE(2)

                 The following increases or decreases in this Global Note have
been made:



                                                                Principal amount
              Amount of decrease     Amount of increase          of this Global               Signature of
                 in Principal           in Principal                  Note                 authorized officer
Date of         Amount of this         Amount of this            following such               of Trustee or
Exchange          Global Note            Global Note          decrease or increase           Notes Custodian
- --------          -----------            -----------          --------------------          ----------------
                                                                               



- ----------

2        This Schedule should only be added if the Security is issued in global
         form.
   65
                                                                              11


                       OPTION OF HOLDER TO ELECT PURCHASE

                  If you want to elect to have this Note purchased by the Note
Issuers pursuant to Section 4.06 or 4.08 of the Indenture, check the box:

                                       / /

                  If you want to elect to have only part of this Note purchased
by the Note Issuers pursuant to Section 4.06 or 4.08 of the Indenture, state the
amount: $


Date: _______________ Your Signature: ______________________________
                                    Sign exactly as your name appears
                                    on the other side of the Security)

Signature Guarantee: _______________________________________
                       (Signature must be guaranteed by a
                       participant in a recognized signature
                       guarantee medallion program)
   66
                                                                       EXHIBIT B

                         FORM OF SUPPLEMENTAL INDENTURE

                  SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated
as of [ ], among [NEW GUARANTOR SUBSIDIARY] (the "New Guarantor Subsidiary"), a
subsidiary of [IRIDIUM OR CAPITAL] (or its successor), a ______________________
(the "Note Issuers"), IRIDIUM OPERATING LLC, a Delaware limited liability
company and IRIDIUM CAPITAL CORPORATION, a Delaware corporation, on behalf of
themselves and the Guarantor Subsidiaries (the "Existing Guarantor
Subsidiaries") under the Indenture referred to below, and STATE STREET BANK AND
TRUST COMPANY, a Massachusetts bank and trust company, as trustee under the
indenture referred to below (the "Trustee").

                              W I T N E S S E T H :

                  WHEREAS Iridium Operating LLC, a Delaware limited liability
company and Iridium Capital Corporation a Delaware corporation, as joint and
several obligors, have heretofore executed and delivered to the Trustee an
Indenture (the "Indenture"), dated as of _______ __, 1998, providing for the
issuance of an aggregate principal amount of up to $350,000,000 of ___% Senior
Notes due 2005, Series D (the "Notes") and the Initial Guarantors agreed to
guarantee those obligations;

                  WHEREAS Section 4.15 of the Indenture provides that under
certain circumstances the Note Issuers are required to cause the New Guarantor
Subsidiary to execute and deliver to the Trustee a supplemental indenture
pursuant to which the New Guarantor Subsidiary shall unconditionally guarantee
all of the Note Issuers' obligations under the Notes pursuant to a Subsidiary
Guaranty on the terms and conditions set forth herein; and

                  WHEREAS pursuant to Section 9.01 of the Indenture, the
Trustee, the Note Issuers and Existing Guarantor Subsidiaries are authorized to
execute and deliver this Supplemental Indenture;

                  NOW THEREFORE, in consideration of the foregoing and for other
good and valuable consideration, the receipt of which is hereby acknowledged,
the New Guarantor Subsidiary, the Note Issuers, the Existing Guarantor
Subsidiaries and the Trustee mutually covenant and agree for the equal and
ratable benefit of the holders of the Notes as follows:

                  1. Definitions. (a) Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture.

         (b) For all purposes of this Supplemental Indenture, except as
otherwise herein expressly provided or unless the context otherwise requires:
(i) the terms and expressions used herein shall have the same meanings as
corresponding terms and expressions used in the Indenture; and (ii) the words
"herein," "hereof" and "hereby" and other words of similar import used in this
Supplement refer to this Supplement as a whole and not to any particular section
hereof.

                  2. Agreement to Guarantee. The New Guarantor Subsidiary hereby
agrees, jointly and severally with all other Guarantor Subsidiaries, to
Guarantee the Note Issuers' obligations under the Notes on the terms and subject
to the conditions set forth in Article X of the Indenture and to be bound by all
other applicable provisions of the Indenture.

                  3. Ratification of Indenture; Supplemental Indentures Part of
Indenture. Except as expressly amended hereby, the Indenture is in all respects
ratified and confirmed and all the terms, conditions and provisions thereof
shall remain in full force and effect. This Supplemental Indenture shall form a
part of the Indenture for all purposes, and every holder of Notes heretofore or
hereafter authenticated and delivered shall be bound hereby.

                  4. Governing Law. THIS SUPPLEMENTAL INDENTURE SHALL BE
GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK
BUT WITHOUT
   67
                                                                               2


GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

                  5. Trustee Makes No Representation. The Trustee makes no
representation as to the validity or sufficiency of this Supplemental Indenture.

                  6. Counterparts. The parties may sign any number of copies of
this Supplemental Indenture. Each signed copy shall be an original, but all of
them together represent the same agreement.

                  7. Effect of Headings. The Section headings herein are for
convenience only and shall not effect the construction thereof.
   68
                                                                               3


                  IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed as of the date first above written.

                                             [NEW GUARANTOR SUBSIDIARY],

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

                                             IRIDIUM OPERATING LLC, on
                                               behalf of itself and the Existing
                                               Guarantor Subsidiaries

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

                                             IRIDIUM CAPITAL CORPORATION

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

                                             STATE STREET BANK AND TRUST
                                             COMPANY,
                                               as Trustee

                                             By:
                                                 -------------------------------
                                                 Name:
                                                 Title:
   69
                                                                      SCHEDULE I

Support Agreement, dated as of July 15, 1992 between Motorola and Iridium, as
successor to Iridium LLC, as amended.