IRIDIUM HOLDINGS LLC CONVERTIBLE SUBORDINATED PROMISSORY NOTE

Exhibit 10.10

Execution Copy

THIS NOTE AND THE SECURITIES ISSUABLE UPON THE CONVERSION HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ ACT ” ), OR ANY STATE SECURITIES LAWS AND MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR TRANSFERRED ABSENT SUCH REGISTRATION OR AN EXEMPTION THEREFROM UNDER SAID ACT AND APPLICABLE STATE LAWS.  

THIS NOTE WAS ISSUED WITH ORIGINAL ISSUE DISCOUNT ( “ OID ” ) FOR UNITED STATES FEDERAL INCOME TAX PURPOSES.  UPON REQUEST, THE COMPANY WILL PROMPTLY MAKE AVAILABLE TO A HOLDER OF THIS NOTE INFORMATION REGARDING THE ISSUE PRICE, THE AMOUNT OF OID, THE ISSUE DATE AND THE YIELD TO MATURITY OF THIS NOTE.  HOLDER SHOULD CONTACT THE CHIEF FINANCIAL OFFICER AT IRIDIUM HOLDINGS LLC, 6707 DEMOCRACY BLVD, SUITE 300, BETHESDA, MARYLAND 20817.

IRIDIUM HOLDINGS LLC

CONVERTIBLE SUBORDINATED PROMISSORY NOTE

FOR VALUE RECEIVED , Iridium Holdings LLC, a Delaware limited liability company (the “ Company ”), promises to pay to Greenhill & Co. Europe Holdings Limited, an English corporation (“ Greenhill ”), or its registered assigns, the principal amount of twenty-two million nine hundred thousand dollars (U.S. $22,900,000), on the Maturity Date, together with accrued interest at the Interest Rate (as defined below), such interest to accrue until the unpaid principal balance is paid in full.  All unpaid principal of this Note, together with any then unpaid and accrued interest and other amounts payable hereunder, shall be due and payable on the seventh anniversary of the date hereof (the “ Maturity Date ”).

The following is a statement of the rights of the Holder and the conditions to which this Note is subject, and to which the Holder, by the acceptance of this Note and the Company, by the issuance of this Note, agree:

1.

Definitions .

As used in this Note, the following capitalized terms have the following meanings:

(a)

“ Additional Common Units ” shall mean all Common Units issued (or, pursuant to Section 8(e), Section 8(h) or Section 8(i), deemed to be issued) by the Company after the Original Issue Date, other than

(i)

Common Units issued (A) pursuant to any bona fide acquisition of assets or operating business by the Company or any bona fide merger or business combination involving the acquisition by the Company of assets or operating business which has been approved by its Board of Directors; provided that any such transaction is at arms-length terms, (B) in connection with any pro rata distribution or split of Common Units in respect of which adjustment has been made pursuant to Section 8(g), (C) to financial institutions or commercial lenders in connection with commercial credit

arrangements, equipment financings or similar transactions, or (D) for commercial reasons and not capital-raising reasons, to potential or existing trade partners or service providers providing trade enabling services; provided that the aggregate Fair Market Value, in each case as determined at the time of issuance, of all Common Units issued pursuant to clauses (C) and (D) hereof may not exceed $15 million;

(ii)

up to30,000 Common Units (including any such Common Units which are repurchased) issued pursuant to the Company’s equity incentive plans; and

(iii)

Common Units issued in connection with any event for which adjustment is made pursuant to Section 8(h) hereof.

(b)

“ Affiliate ” means, with respect to any Person, any other Person directly or indirectly controlling, controlled by, or under common control of such Person.

(c)

“ Business Day ” means any day except a Saturday, Sunday or other day on which commercial banks in the City of New York are authorized by law to close.

(d)

“ Change of Control ” means the acquisition, directly or indirectly, by any Person who as of the date hereof does not control at least 25% of the Common Units, of the beneficial ownership (as defined in Rule 13d-3 promulgated under the Securities Exchange Act of 1934) in the Common Units representing more than 50% of all outstanding Common Units at such time.

(e)

“ Class A Units ” shall have the meaning set forth in the LLC Agreement.

(f)

“ Class B Units ” shall have the meaning set forth in the LLC Agreement.

(g)

“ Common Units ” or “ Units ” shall mean either (i) Class A Units or Class B Units or (ii) both Class A Units and Class B Units taken together.

(h)

“ Conversion Date ” shall have the meaning set forth in Section 8(d)(i).

(i)

“ Convertible Securities ” shall mean any evidences of indebtedness, shares of capital stock or other securities directly or indirectly convertible into or exchangeable for Common Units (other than the Note and the Common Units).

(j)

“ Event of Default ” has the meaning given in Section 5 hereof.

(k)

“ Fair Market Value ” as of any date means the fair market value as of such date as determined in good faith by the Board of Directors; provided that if the Holder objects to such determination, the Board of Directors shall retain an independent appraiser of national reputation reasonably satisfactory to the Holder in order to determine such fair market value, and such appraiser’s determination of the fair market value shall be binding hereunder (and the fees and expenses of such appraiser shall be borne equally by the Company and the Holder).

(l)

“ Holder ” means Greenhill and any other Person or Persons who shall at the time be the registered holder of this Note.

(m)

“ Initial Public Offering ” means any offering of the common equity securities of the Company (or its successor) to the public which results in net proceeds of at least $100 million pursuant to an effective registration statement under the Securities Act of 1933, as then in effect.

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(n)

“ Interest Rate ” means 0% initially and, six months after the issuance date, 5% per annum.

(o)

“ LLC Agreement ” means the Amended and Restated Limited Liability Company Agreement of Iridium Holdings LLC.

(p)

“ Lien ” means with respect to any property or asset, any mortgage, lien, pledge, charge, security interest, encumbrance or other adverse claim of any kind in respect of such property or asset.

(q)

“ Note Payment Amount ” means, as of any Business Day, with respect to this Note, the aggregate unpaid Principal Amount outstanding plus the aggregate amount of accrued but unpaid interest with respect to the Note.

(r)

“ Note Purchase Agreement ” means the note purchase agreement among the Company and Greenhill dated as of September 22, 2008.

(s)

“ Options ” mean rights, options or warrants to subscribe for, purchase or otherwise acquire Common Units or Convertible Securities.

(t)

“ Original Issue Date ” shall mean the date of the issuance of this Note.

(u)

“ Person ” means an individual, corporation, partnership, limited liability company, association, trust or other entity or organization, including a government or political subdivision or an agency or instrumentality thereof.

(v)

“ Principal Amount ” means $22,900,000.

(w)

“ Termination Event ” shall mean the termination of the Transaction Agreement pursuant to the terms thereof.

(x)

“ Transaction Agreement ” means the Transaction Agreement dated as of September 22, 2008 among the Company, GHL Acquisition Corp. and certain other parties.

2.

Interest .   Interest shall be calculated on the principal amount and accrue at a rate per annum equal to the Interest Rate, compounded quarterly and computed on the basis of the actual number of days elapsed and a year of 365 days.  Interest will not be paid until the date the Note is repaid or redeemed as provided in Section 3(a) or Section 7, as applicable.

3.

Payment .

(a)

Payment of the Note .  Subject to earlier conversion or repayment thereof pursuant to Section 7 or Section 8 hereof, the outstanding principal and all accrued interest on this Note shall be due and payable in full on the Maturity Date.  This Note will not be prepayable at the option of the Company.

(b)

Method of Payments .

(i)

Except to the extent otherwise provided herein, each payment by the Company of principal and interest owing under this Note shall be made in dollars in immediately available funds, without deduction, set-off or counterclaim, not later than 2:00 p.m. New York City Time

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on the date on which such payment shall become due by wire transfer to such account(s) as the Holder may notify the Company in writing.

(ii)

Notwithstanding anything to the contrary contained herein, if any due date under this Note would otherwise fall on a day that is not a Business Day, such date shall be extended to the next succeeding Business Day, and interest shall be payable for any principal so extended for the period of such extension.

4.

Notice of Defaults .   Promptly upon (but in no event later than three (3) Business Days after) the occurrence thereof, the Company will provide the Holder written notice of the occurrence of (i) any Event of Default hereunder or (ii) any event or circumstance which, with the giving of notice, passage of time, or both, will constitute an Event of Default.

5.

Events of Default and Right to Cure .   The occurrence of any of the following shall constitute an “ Event of Default ” under this Note:

(a)

Failure to Pay Principal or Interest . The Company fails to make a payment, when due, of any principal or interest due on this Note and, in the case of interest, such default continues for a period of ten (10) days.

(b)

Breach of Covenants or Agreements. Any material breach by the Company of any provision this Note, and such default continues for a period of ten (10) days.

(c)

Voluntary Bankruptcy or Insolvency Proceedings.   The Company shall (i) apply for or consent to the appointment of a receiver, trustee, liquidator or custodian of itself or of all or a substantial part of its property, (ii) be unable, or admit in writing its inability, to pay its debts generally as they mature, (iii) make a general assignment for the benefit of its or any of its creditors, (iv) be dissolved or liquidated, or (v) commence a voluntary case or other proceeding seeking liquidation, reorganization or other relief with respect to itself or its debts under any bankruptcy, insolvency or other similar law now or hereafter in effect or consent to any such relief or to the appointment of or taking possession of its property by any official in an involuntary case or other proceeding commenced against it.

(d)

Involuntary Bankruptcy or Insolvency Proceedings.   Proceedings for the appointment of a receiver, trustee, liquidator or custodian of the Company or of all or a substantial part of its property, or an involuntary case or other proceedings seeking liquidation, reorganization or other relief with respect to the or its debts under any bankruptcy, insolvency or other similar law now or hereafter in effect shall be commenced and an order for relief entered or such proceeding shall not be dismissed or discharged within 30 days of commencement.

6.

Rights of Holder upon Default .  If any Event of Default occurs, the Holder, by written notice to the Company with respect to the Event of Default specified in Section 5(a) or Section 5(b) and without any notice with respect to the Event of Default specified in Section 5(c) or Section 5(d), may:

(a)

declare the entire unpaid principal of the Note and accrued interest thereon due and payable and such principal and accrued interest shall thereupon become due and payable without presentment, notice, protest or demand of any kind (all of which are expressly waived by the Company); and

(b)

take all actions available to them, at law or in equity, to collect or otherwise enforce the Note.

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7.

Redemption .  (a)  In the event of a Change of Control, the Holder of this Note may demand, at its option, that the Company redeem the Note in full for the Note Payment Amount outstanding on the date of such Change of Control.

(b)

In the event of a Termination Event, after January 31, 2013, the Holder may require, at its option, that the Company redeem the Note in full for the Note Payment Amount (as of such date).

(c)

Any redemption payment pursuant to paragraph (a) or (b) above shall be made within five Business Days of a written notice from the Holder demanding redemption, in each case against delivery of this Note.  

8.

Conversion .

(a)

Optional Conversion .  Subject to the terms and conditions of this Section 8, upon the later of (x) the first anniversary hereof and (y) the earlier of the occurrence of a Termination Event or the closing of the transactions contemplated by the Transaction Agreement (if notice of exercise of the right to convert is given not less than one Business Day before such closing), the Holder shall have the right, at any time and from time to time, at the Holder’s option, to convert all of this Note into a number of Class A Units of the Company equal to the Note Payment Amount (as of the date of such conversion) divided by the Conversion Price.

(b)

Termination of Optional Conversion .  Unless the Holder has exercised its right under Section 8(a) immediately prior to the earlier of (i) the closing of the transactions contemplated by the Transaction Agreement (unless notice of exercise of the right to convert has been given in accordance with Section 8(a)) or (ii) the closing of an Initial Public Offering, then the right to convert set forth in this Section 8 shall irrevocably terminate and the Company shall have, for a period of ten (10) Business Days following the date of such closing, the right to redeem, in its sole discretion, the Note at a price equal to the Principal Amount plus any accrued interest on the Note incurred up and until the date of such redemption; provided , in each case, that if the Holder did not have the right to exercise such conversion as a result of the operation of clause (x) of Section 8(a), then the “closing” of transactions described in clauses (i) and (ii) above shall be deemed replaced by “the fifth Business Day following the first anniversary hereof.”

(c)

Conversion Price .  The initial conversion price (as adjusted from time to time, the “ Conversion Price ”) shall be $272.87.

(d)

Adjustment of Conversion Prices Upon Issuance of Additional Common Units.   In the event that after the Original Issue Date the Company shall issue Additional Common Units for a consideration per Unit (determined pursuant to Section 8(f)) less than the Conversion Price in effect immediately prior to such issue, then and in such event, the Conversion Price shall be reduced, concurrently with such issue, to a price equal to the consideration per Unit (determined pursuant to Section 8(f)) received by the Company for the issue of such Additional Common Units.

(e)

Deemed Issue of Additional Common Units .  In the event the Company at any time or from time to time after the Original Issue Date shall issue any Options or Convertible Securities or shall fix a record date for the determination of holders of any class of securities entitled to receive any such Options or Convertible Securities, then, if the Common Units issuable upon exercise and conversion thereof would constitute Additional Common Units, the Common Units issuable upon the exercise of such Options or, in the case of Convertible Securities a