XM ESCROW LLC XM SATELLITE RADIO INC. $778,500,000 13% Senior Notes due 2014 PURCHASE AGREEMENT

Exhibit 4.65

Execution Copy

XM ESCROW LLC

XM SATELLITE RADIO INC.

$778,500,000 13% Senior Notes due 2014

PURCHASE AGREEMENT

July 24, 2008

New York, New York

J.P. MORGAN SECURITIES INC.

UBS SECURITIES LLC

MORGAN STANLEY & CO. INCORPORATED

c/o J.P. Morgan Securities Inc.

270 Park Avenue

New York, New York 10017

Ladies and Gentlemen:

XM Escrow LLC, a Delaware limited liability company (“XM Escrow”), XM Satellite Radio Inc., a Delaware corporation (the “Company”), XM Satellite Radio Holdings Inc., a Delaware corporation (“XM Holdings”), and each of the other Guarantors (as defined herein) agree with you as follows:

1. Issuance of Notes. XM Escrow proposes to issue and sell to J.P. Morgan Securities Inc. (the “Representative”) and UBS Securities LLC and Morgan Stanley & Co. Incorporated (together with the Representative, the “Initial Purchasers”) $778,500,000 aggregate principal amount of 13% Senior Notes due 2014 (the “Senior Notes”). The Securities (as defined below) will be issued pursuant to an indenture (the “Indenture”), to be dated as of the Closing Date (as defined herein), by and between XM Escrow and The Bank of New York, N.A., as trustee (the “Trustee”). XM Escrow is expected to merge with and into the Company with the Company as the surviving entity (the “Escrow Merger”) immediately prior to the merger contemplated by the Agreement and Plan of Merger, dated as of February 19, 2007, among XM Holdings, Sirius Satellite Radio Inc. (“Sirius”), and Vernon Merger Corporation (as amended or supplemented by any subsequent letter agreement, the “Merger Agreement”), pursuant to which Vernon Merger Corporation shall be merged with and into XM Holdings with XM Holdings as the surviving corporation (the “Sirius Merger,” and, together with the Escrow Merger, the “Mergers”).

Upon consummation of the Escrow Merger, the Company will succeed to the obligations of XM Escrow hereunder and under the Note Documents (as defined below). Upon consummation of this offering, the Company and XM Escrow will execute a supplemental indenture to the Indenture in connection therewith (the “Assumption Indenture”). In addition, upon consummation of the Escrow Merger,

the Company’s obligations under the Senior Notes will be, jointly and severally, unconditionally guaranteed (the “Guarantees”), on a senior basis, by XM Holdings and each of the other guarantors listed on the signature pages hereto (collectively, the “Guarantors,” and together with the Company and XM Escrow, the “Issuers”). Upon consummation of this offering, the Company, XM Escrow and the Guarantors will execute a supplemental indenture to the Indenture in connection with the Guarantees (the “Guarantor Indenture” and the Indenture, as amended by the Assumption Indenture and the Guarantor Indenture, the “Post-Merger Indenture”). The Senior Notes and the Guarantees thereof are referred to herein as the “Securities.”

Pursuant to this Purchase Agreement (this “Agreement”), the Indenture and the escrow and security agreement (the “Escrow Agreement”) among XM Escrow, XM Holdings, The Bank of New York, as trustee and JPMorgan Chase Bank, N.A., as escrow agent (the “Escrow Agent”), XM Escrow is required on the Closing Date to (i) direct the Initial Purchasers to deposit into an escrow account (the “Escrow Account”) $684,002,633.85 (the aggregate purchase price of the Senior Notes, as determined in accordance with Section 2 hereof, such amount being the “Offering Proceeds”) and (ii) deposit or have deposited on its behalf an amount, together with the Offering Proceeds, sufficient to redeem the Senior Notes in cash at the redemption price equal to 100.0% of the accreted value of the Senior Notes, plus accrued interest to, but not including October 31, 2008) (such amount, together with the Offering Proceeds, the “Initial Escrow Amount”, and together with all proceeds from the investment of the Initial Escrow Amount by the Escrow Agent, the “Escrowed Funds”). Unless the Initial Escrow Amount is released by the Escrow Agent to effectuate a Special Redemption (as such term is defined in the Indenture), the Escrowed Funds shall be released to XM Escrow at one time to be used in the manner described in the Pricing Disclosure Package under the caption “Use of proceeds.”

The Securities will be offered and sold to the Initial Purchasers pursuant to an exemption from the registration requirements under the Securities Act of 1933, as amended (the “Act”). The Issuers have prepared a preliminary offering memorandum, dated as of July 20, 2008 (the “Preliminary Offering Memorandum”), a preliminary offering memorandum supplement dated July 24, 2008 (the “Supplement”) and a pricing supplement thereto dated the date hereof including the information attached hereto as Exhibit B (the “Pricing Supplement”). The Preliminary Offering Memorandum, the Supplement and the Pricing Supplement are herein referred to as the “Pricing Disclosure Package.” Promptly after the execution of this Agreement, the Issuers will prepare a final offering memorandum dated the date hereof (the “Final Offering Memorandum”). Unless stated to the contrary, any references herein to the terms “Pricing Disclosure Package” and “Final Offering Memorandum” shall be deemed to refer to and include any information filed under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), prior to the date hereof and incorporated by reference therein, and any references herein to the terms “amend,” “amendment” or “supplement” with respect to the Final Offering Memorandum shall be deemed to refer to and include any information filed under the Exchange Act subsequent to the date hereof that is incorporated by reference therein. All references in this Agreement to financial statements and schedules and other information which is “contained,” “included” or “stated” (or other references of like import) in the Pricing Disclosure Package (including the Preliminary Offering Memorandum) or the Final Offering Memorandum shall be deemed to mean and include all such financial statements and schedules and other information which are incorporated by reference in the Pricing Disclosure Package or the Final Offering Memorandum, as the case may be.

The Initial Purchasers have advised the Issuers that the Initial Purchasers intend, as soon as they deem practicable after this Agreement has been executed and delivered, to resell (the “Exempt Resales”) the Securities in private sales exempt from registration under the Act on the terms set forth in the Pricing Disclosure Package, solely to (i) persons whom the Initial Purchasers reasonably believe to be “qualified institutional buyers” (“QIBs”), as defined in Rule 144A under the Act (“Rule 144A”), in accordance

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with Rule 144A and (ii) other eligible purchasers pursuant to offers and sales that occur outside the United States within the meaning of Regulation S under the Act (“Regulation S”) in accordance with Regulations S (the persons specified in clauses (i) and (ii), the “Eligible Purchasers”).

The Securities are being offered and sold by the Issuers in connection with the refinancing of certain debt obligations of the Issuers, as described in the Pricing Disclosure Package under the caption “Summary—Refinancing transactions” (the “Refinancing Transactions”).

This Agreement, the Senior Notes, the Guarantees, the Indenture, the Post-Merger Indenture and the Escrow Agreement are hereinafter sometimes referred to collectively as the “Note Documents.” The issuance and sale of the Securities, the Refinancing Transactions and the consummation of the Mergers are collectively referred to as the “Transactions.”

2. Agreements to Sell and Purchase. On the basis of the representations, warranties and covenants contained in this Agreement, the Issuers agree to issue and sell to the Initial Purchasers, and on the basis of the representations, warranties and covenants contained in this Agreement, and subject to the terms and conditions contained in this Agreement, each of the Initial Purchasers, severally and not jointly, agrees to purchase from XM Escrow, the aggregate principal amount of the Senior Notes set forth opposite its name on Schedule I attached hereto. The purchase price for the Senior Notes shall be 87.861610% of their principal amount.

3. Delivery and Payment. Delivery of, and payment of the purchase price for, the Securities shall be made at 10:00 a.m., New York time, on July 31, 2008 (such date and time, the “Closing Date”) at the offices of Latham & Watkins LLP, 885 Third Avenue, New York, New York 10022. The Closing Date and the location of delivery of and the form of payment for the Securities may be varied by mutual agreement between the Initial Purchasers and the Company.

The Securities shall be delivered by the Issuers to the Initial Purchasers (or as the Initial Purchasers direct) through the facilities of The Depository Trust Company (“DTC”) against payment by the Initial Purchasers of the purchase price therefor by means of wire transfer of immediately available funds to such account or accounts specified by the Company in accordance with Section 8(i) on or prior to the Closing Date, or by such means as the parties hereto shall agree prior to the Closing Date. The Securities shall be evidenced by one or more certificates in global form registered in such names as the Initial Purchasers may request upon at least one business day’s notice prior to the Closing Date and having an aggregate principal amount corresponding to the aggregate principal amount of the Securities.

4. Agreements of the Issuers. The Issuers, jointly and severally, covenant and agree with the Initial Purchasers as follows:

(a) To furnish the Initial Purchasers and those persons identified by the Initial Purchasers, without charge, as many copies of the Preliminary Offering Memorandum, the Supplement, the Pricing Supplement, any Issuer Written Communication (as defined below) and the Final Offering Memorandum, and any amendments or supplements thereto, as the Initial Purchasers may reasonably request. The Issuers consent to the use of the Preliminary Offering Memorandum, the Supplement, the Pricing Supplement and the Final Offering Memorandum by the Initial Purchasers in connection with Exempt Resales.

(b) As promptly as practicable following the execution and delivery of this Agreement and in any event not later than the second business day following the date hereof, to prepare and deliver to the Initial Purchasers the Final Offering Memorandum, which shall consist of the

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Preliminary Offering Memorandum as modified only by the information contained in the Supplement and the Pricing Supplement; not to amend or supplement the Preliminary Offering Memorandum (other than as amended by the Supplement), the Supplement or the Pricing Supplement; not to amend or supplement the Final Offering Memorandum prior to the Closing Date unless the Initial Purchasers shall previously have been advised of such proposed amendment or supplement at least two business days prior to the proposed use, and shall not have objected to such amendment or supplement.

(c) If, prior to the later of (x) the Closing Date and (y) the time that the Initial Purchasers have completed their distribution of the Securities, any event shall occur that, in the judgment of the Issuers or in the judgment of counsel to the Initial Purchasers, makes any statement of a material fact in the Pricing Disclosure Package or the Final Offering Memorandum, as either is then amended or supplemented, untrue or that requires the making of any additions to or changes in the Pricing Disclosure Package or Final Offering Memorandum in order to make the statements in the Pricing Disclosure Package or the Final Offering Memorandum, as either is then amended or supplemented, in the light of the circumstances under which they are made, not misleading, or if it is necessary to amend or supplement the Pricing Disclosure Package or the Final Offering Memorandum to comply with all applicable laws, the Company shall promptly notify the Initial Purchasers of such event and (subject to Section 4(b)) prepare an appropriate amendment or supplement to the Pricing Disclosure Package or the Final Offering Memorandum so that (i) the statements in the Pricing Disclosure Package or Final Offering Memorandum, as amended or supplemented, will not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances at the Closing Date and at the time of sale of Securities, not misleading and (ii) the Pricing Disclosure Package and the Final Offering Memorandum will comply with applicable law.

(d) To qualify or register the Securities under the securities laws of such jurisdictions as the Initial Purchasers may request and to continue such qualification in effect so long as required for the Exempt Resales. Notwithstanding the foregoing, no Issuer shall be required to qualify as a foreign corporation in any jurisdiction in which it is not so qualified or to execute a general consent to service of process in any such jurisdiction or subject itself to taxation in excess of a nominal dollar amount in any such jurisdiction where it is not then so subject.

(e) To advise the Initial Purchasers promptly, and if requested by the Initial Purchasers, to confirm such advice in writing, of the issuance by any securities commission of any stop order suspending the qualification or exemption from qualification of any of the Securities for offering or sale in any jurisdiction, or the initiation of any proceeding for such purpose by any securities commission or other regulatory authority. The Issuers shall use their reasonable best efforts to prevent the issuance of any stop order or order suspending the qualification or exemption of any of the Securities under any securities laws, and if at any time any securities commission or other regulatory authority shall issue an order suspending the qualification or exemption of any of the Securities under any securities laws, the Issuers shall use their reasonable best efforts to obtain the withdrawal or lifting of such order at the earliest possible time.

(f) Whether or not the transactions contemplated by this Agreement are consummated, to pay all costs, expenses, fees and disbursements (including fees and disbursements of counsel and accountants for the Issuers) incurred and stamp, documentary or similar taxes incident to and in connection with: (i) the preparation, printing and distribution of the Preliminary Offering Memorandum, the Supplement, the Pricing Supplement, any Issuer Written Communication and the Final Offering Memorandum and any amendments or supplements thereto, (ii) all

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expenses (including travel expenses) of the Issuers and the Initial Purchasers in connection with any meetings with prospective investors in the Securities, (iii) the preparation, notarization (if necessary) and delivery of the Note Documents and all other agreements, memoranda, correspondence and documents prepared and delivered in connection with this Agreement and with the Exempt Resales, (iv) the issuance, transfer and delivery of the Securities by the Issuers to the Initial Purchasers, (v) the qualification or registration of the Securities for offer and sale under the securities laws of the several states of the United States or provinces of Canada (including, without limitation, the cost of printing and mailing preliminary and final Blue Sky or legal investment memoranda and fees and disbursements of counsel (including local counsel) to the Initial Purchasers relating thereto), (vi) the application for quotation of the Securities in The PORTAL Market (“Portal”) of The Nasdaq Stock Market, (vii) the inclusion of the Securities in the book-entry system of DTC, (viii) the rating of the Securities by rating agencies, (ix) the fees and expenses of the Trustee and its counsel and (x) the performance by the Issuers of their other obligations under the Note Documents. For the avoidance of doubt, the Issuers’ obligations under this Section 4(f) shall not affect any expense sharing or contribution arrangements one or more of the Issuers may have with Sirius.

(g) To use the proceeds from the sale of the Securities in the manner described in the Pricing Disclosure Package under the caption “Use of proceeds,” unless XM Escrow is required to effectuate a Special Redemption pursuant to the Indenture.

(h) To use its best efforts to do and perform all things required to be done and performed under this Agreement by it prior to or after the Closing Date and to satisfy all conditions precedent on their part to the delivery of the Securities.

(i) Not to, and not to permit any Subsidiary (as defined herein) nor any affiliates (as defined in Rule 501(b) of Regulation D under the Act) to, sell, offer for sale or solicit offers to buy any security (as defined in the Act) that would be integrated with the sale of the Securities in a manner that would require the registration under the Act of the sale of the Securities to the Initial Purchasers or any Eligible Purchasers.

(j) Not to, and to cause its affiliates (as defined in Rule 144 under the Act) not to, resell any of the Securities that have been reacquired by any of them.

(k) Not to engage, not to allow any Subsidiary to engage, and to cause its other affiliates and any person acting on their behalf (other than, in any case, the Initial Purchasers and any of their affiliates, as to whom the Issuers make no covenant) not to engage, in any form of general solicitation or general advertising (within the meaning of Regulation D under the Act) in connection with any offer or sale of the Securities in the United States.

(l) Not to engage, not to allow any Subsidiary to engage, and to cause its other affiliates and any person acting on their behalf (other than, in any case, the Initial Purchasers and any of their affiliates, as to whom the Issuers make no covenant) not to engage, in any directed selling effort with respect to the Securities, and to comply with the offering restrictions requirement of Regulation S. Terms used in this paragraph have the meanings given to them by Regulation S.

(m) From and after the Closing Date, for so long as any of the Securities remain outstanding and are “restricted securities” within the meaning of Rule 144(a)(3) under the Act and during any period in which XM Holdings is not subject to Section 13 or 15(d) of the Exchange

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Act, to make available upon request the information required by Rule 144A(d)(4) under the Act to (i) any holder or beneficial owner of Securities in connection with any sale of such Securities and (ii) any prospective purchaser of such Securities from any such holder or beneficial owner designated by the holder or beneficial owner. XM Holdings will pay the expenses of preparing, printing and distributing such documents.

(n) [Intentionally Omitted].

(o) To comply with their obligations under the letter of representations to DTC relating to the approval of the Securities by DTC for “book-entry” transfer and to use their best efforts to obtain approval of the Securities by DTC for “book-entry” transfer.

(p) Prior to the Closing Date, to furnish without charge to the Initial Purchasers, (i) all reports and other communications (financial or otherwise) that XM Holdings mails or otherwise makes available to its security holders and (ii) such other information as the Initial Purchasers shall reasonably request.

(q) Not to, and not to permit any of its affiliates or anyone acting on its or its affiliates’ behalf to (other than the Initial Purchasers and their affiliates), distribute prior to the Closing Date any offering material in connection with the offer and sale of the Securities other than the Preliminary Offering Memorandum, the Supplement, the Pricing Supplement, any “road show” (as defined in Rule 433 under the Securities Act) and the Final Offering Memorandum. Before making, preparing, using, authorizing, approving or referring to any Issuer Written Communication, the Issuers will furnish to the Representative and counsel for the Initial Purchasers a copy of such written communication for review and will not make, prepare, use, authorize, approve or refer to any such written communication to which the Representative reasonably objects.

(r) During the period of two years after the Closing Date or, if earlier, until such time as the Securities are no longer restricted securities (as defined in Rule 144 under the Act), not to be or become a closed-end investment company required to be registered, but not registered, under the Investment Company Act of 1940.

(s) In connection with the offering, until the Initial Purchasers shall have notified XM Holdings and the Company of the completion of the distribution of the Securities, not to, and not to permit any of their affiliates (as such term is defined in Rule 501(b) of Regulation D under the Act) to, either alone or with one or more other persons, bid for or purchase for any account in which it or any of their affiliates has a beneficial interest, for the purpose of creating actual or apparent active trading in, or of raising the price of, the Securities.

(t) To use their reasonable best efforts to effect the inclusion of the Securities in Portal.

(u) During the period from the date hereof through and including the date that is 90 days after the date hereof, without the prior written consent of the Representative, offer, sell, contract to sell or otherwise dispose of in any transaction required to be registered under the Act or pursuant to Rule 144A, any debt securities issued or guaranteed by XM Holdings, XM Escrow, the Company or any Subsidiary and having a tenor of more than one year, provided, however, that the foregoing restriction shall not apply to debt securities issued in connection with the Refinancing Transactions or a letter of credit or other collateral used to replace the MLB escrow arrangement, in an amount not to exceed $120.0 million.

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(v) To deposit the Offering Proceeds into the Escrow Account and to comply with all of its agreements set forth in the Escrow Agreement and to use its best efforts to do and perform all things necessary to perfect a first priority security interest in Escrowed Funds and the other Collateral (as such terms are defined in the Escrow Agreement).

(w) Upon consummation of the Escrow Merger, that the Company shall assume all of XM Escrow’s obligations under the Note Documents pursuant to the Assumption Indenture and the Escrow Merger Agreement.

5. Representations and Warranties. (a) The Issuers, jointly and severally, represent and warrant to the Initial Purchasers that, as of the date hereof and as of the Closing Date:

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Each certificate signed by any officer of any Issuer and delivered to the Initial Purchasers or counsel for the Initial Purchasers pursuant to, or in connection with, this Agreement shall be deemed to be a representation and warranty by the Issuers to the Initial Purchasers as to the matters covered by such certificate.

The Issuers acknowledge that the Initial Purchasers and, for purposes of the opinions to be delivered to the Initial Purchasers pursuant to Section 8 of this Agreement, counsel to the Issuers and counsel to the Initial Purchasers will rely upon the accuracy and truth of the foregoing representations and the Issuers hereby consent to such reliance.

(b) Each Initial Purchaser represents that it is a QIB and acknowledges that it is purchasing the Securities pursuant to a private sale exemption from registration under the Act, and that the Securities have not been registered under the Act and may not be offered or sold within the United States or to, or for the account or benefit of, U.S. persons except pursuant to an exemption from the registration requirements of the Act. Each Initial Purchaser, severally and not jointly, represents, warrants and covenants to the Issuers that:

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Each Initial Purchaser severally agrees that, at or prior to confirmation of a sale of Securities pursuant to Regulation S it will have sent to each distributor, dealer or person receiving a selling concession, fee or other remuneration that purchases Securities from it or through it during the restricted period a confirmation or notice to substantially the following effect:

“The Securities covered hereby have not been registered under the United States Securities Act of 1933, as amended (the “Securities Act”), and may not be offered or sold within the United States or to or for the account or benefit of, U.S. persons (i) as part of their distribution at any time and (ii) otherwise until forty days after the later of the date upon which the offering of the Securities commenced and the date of closing, except in either case in accordance with Regulation S or Rule 144A under the Securities Act. Terms used above have the meaning given to them by Regulation S.”

The Initial Purchasers understand that the Issuers and, for purposes of the opinions to be delivered to them pursuant to Section 8 hereof, counsel to the Issuers and counsel to the Initial Purchasers will rely upon the accuracy and truth of the foregoing representations, and each Initial Purchaser hereby consents to such reliance.

6. Indemnification. (a) The Issuers, jointly and severally, agree to indemnify and hold harmless the Initial Purchasers, each person, if any, who controls any Initial Purchaser within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act, the agents, employees, officers and directors of any Initial Purchaser and the agents, employees, officers and directors of any such controlling person from and against any and all losses, liabilities, claims, damages and expenses whatsoever (including, but not limited, to reasonable attorneys’ fees and any and all reasonable expenses whatsoever incurred in investigating, preparing or defending against any litigation, commenced or threatened, or any claim whatsoever, and any and all reasonable amounts paid in settlement of any claim or litigation) (collectively, “Losses”) to which they or any of them may become subject under the Act, the Exchange Act or otherwise insofar as such Losses (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the Pricing Disclosure Package, any Issuer Written Communication (including, but not limited to, any “road show,” as defined in Rule 433 under the Securities Act), the Final Offering Memorandum, or in any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that none of the Issuers will be liable in any such case to the extent, but only to the extent, that any such Loss arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission relating to an Initial Purchaser made therein in reliance upon and in conformity with written information furnished to XM Escrow and the Company by or on behalf of such Initial Purchaser through the Representative expressly for use therein. This indemnity agreement will be in addition to any liability that the Issuers may otherwise have, including, but not limited to, liability under this Agreement.

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(b) Each Initial Purchaser agrees to indemnify and hold harmless the Issuers, and each person, if any, who controls any of the Issuers within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act, the agents, employees, officers and directors and the agents, employees, officers and directors of any of the Issuers of any such controlling person from and against any and all Losses to which they or any of them may become subject under the Act, the Exchange Act or otherwise insofar as such Losses (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the Pricing Disclosure Package or the Final Offering Memorandum, or in any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, in each case to the extent, but only to the extent, that any such Loss arises out of or is based upon any untrue statement or alleged untrue statement or omission or alleged omission relating to such Initial Purchaser made therein in reliance upon and in conformity with information furnished in writing to XM Escrow and the Company by or on behalf of such Initial Purchaser through the Representative expressly for use therein.

(c) Promptly after receipt by an indemnified party under subsection 6(a) or 6(b) above of notice of the commencement of any action, suit or proceeding (collectively, an “action”), such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify each party against whom indemnification is to be sought in writing of the commencement of such action; provided that the failure so to notify an indemnifying party shall not relieve such indemnifying party from any liability that it may have under this Section 6 except to the extent that it has been prejudiced in any material respect by such failure; and provided further, that the failure to notify an indemnifying party shall not relieve such indemnifying party from any liability that it may have to an indemnified person otherwise than under this Section 6. In case any such action is brought against any indemnified party, and it notifies an indemnifying party of the commencement of such action, the indemnifying party will be entitled to participate in such action, and to the extent it may elect by written notice delivered to the indemnified party promptly after receiving the aforesaid notice from such indemnified party, to assume the defense of such action with counsel satisfactory to such indemnified party. Notwithstanding the foregoing, the indemnified party or parties shall have the right to employ its or their own counsel in any such action, but the reasonable fees and expenses of such counsel shall be at the expense of such indemnified party or parties unless (i) the employment of such counsel shall have been authorized in writing by the indemnifying parties in connection with the defense of such action, (ii) the indemnifying parties shall not have employed counsel to take charge of the defense of such action within a reasonable time after notice of commencement of the action, or (iii) the named parties to such action (including any impleaded parties) include such indemnified party and the indemnifying parties (or such indemnifying parties have assumed the defense of such action), and such indemnified party or parties shall have reasonably concluded that there may be defenses available to it or them that are different from or additional to those available to one or all of the indemnifying parties (in which case the indemnifying parties shall not have the right to direct the defense of such action on behalf of the indemnified party or parties), in any of which events such reasonable fees and expenses of counsel shall be borne by the indemnifying parties. In no event shall the indemnifying parties be liable for the fees and expenses of more than one counsel (together with appropriate local counsel) at any time for all indemnified parties in connection with any one action or separate but substantially similar or related actions arising in the same jurisdiction out of the same general allegations or circumstances. An indemnifying party shall not be liable for any settlement of any claim or action effected without its written consent, which consent may not be unreasonably withheld. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as

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contemplated by paragraph (a) or (b) of this Section 6, then the indemnifying party agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 45 days after receipt by such indemnifying party of the aforesaid request, (ii) such indemnifying party shall not have reimbursed the indemnified party in accordance with such request prior to the date of such settlement and (iii) such indemnified party shall have given the indemnifying party at least 45 days’ prior notice of its intention to settle. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened proceeding in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party, unless such settlement (x) includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such proceeding and (y) does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

7. Contribution. In order to provide for contribution in circumstances in which the indemnification provided for in Section 6 of this Agreement is for any reason held to be unavailable from the indemnifying party, or is insufficient to hold harmless a party indemnified under Section 6 of this Agreement, each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such aggregate Losses (i) in such proportion as is appropriate to reflect the relative benefits received by the Issuers, on the one hand, and the Initial Purchasers, on the other hand, from the offering of the Securities or (ii) if such allocation is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to above but also the relative fault of the Issuers, on the one hand, and the Initial Purchasers, on the other hand, in connection with the statements or omissions that resulted in such Losses, as well as any other relevant equitable considerations. The relative benefits received by the Issuers, on the one hand, and the Initial Purchasers, on the other hand, shall be deemed to be in the same proportion as (x) the total proceeds from the offering of Securities (net of discounts and commissions but before deducting expenses) received by the Issuers are to (y) the total discount and commissions received by the Initial Purchasers. The relative fault of the Issuers, on the one hand, and the Initial Purchasers, on the other hand, shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by an Issuer or the Initial Purchasers and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission or alleged statement or omission.

The Issuers and the Initial Purchasers agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation or by any other method of allocation that does not take into account the equitable considerations referred to above. Notwithstanding the provisions of this Section 7, (i) in no case shall any Initial Purchaser be required to contribute any amount in excess of the amount by which the total discount and commissions applicable to the Securities purchased by such Initial Purchaser pursuant to this Agreement exceeds the amount of any damages that such Initial Purchaser has otherwise been required to pay by reason of any untrue or alleged untrue statement or omission or alleged omission and (ii) no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. For purposes of this Section 7, each person, if any, who controls any Initial Purchaser within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act shall have the same rights to contribution as the Initial Purchasers, and each person, if any, who controls an Issuer within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act and each director, officer, employee and agent of an Issuer shall have the same rights to contribution as the Issuers. Any party entitled to contribution will, promptly after receipt of notice of commencement of any action against such party in respect of which a claim for contribution may be made against another party or parties under this Section 7, notify such party or parties from whom contribution may be sought, but the

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omission to so notify such party or parties shall not relieve the party or parties from whom contribution may be sought from any obligation it or they may have under this Section 7 or otherwise, except to the extent that it has been prejudiced in any material respect by such failure; provided, however, that no additional notice shall be required with respect to any action for which notice has been given under Section 6 for purposes of indemnification. Anything in this section to the contrary notwithstanding, no party shall be liable for contribution with respect to any action or claim settled without its written consent; provided, however, that such written consent was not unreasonably withheld.

8. Conditions of Initial Purchasers’ Obligations. The obligations of the Initial Purchasers to purchase and pay for the Securities, as provided for in this Agreement, shall be subject to satisfaction of the following conditions prior to or concurrently with such purchase:

(a) All of the representations and warranties of the Issuers contained in this Agreement shall be true and correct on the date of this Agreement and on the Closing Date. The Issuers shall have performed or complied with all of the agreements and covenants contained in this Agreement and required to be performed or complied with by them at or prior to the Closing Date. The Initial Purchasers shall have received certificates, dated the Closing Date, signed by any combination of two of the chairman of the board of directors, chief executive officer, chief financial officer and general counsel of each of XM Holdings and the Company, certifying as to the foregoing and to the effect in Section 8(c), among other matters.

(b) The Final Offering Memorandum shall have been printed and copies distributed to the Initial Purchasers as required by Section 5(b). No stop order suspending the qualification or exemption from qualification of the Securities in any jurisdiction shall have been issued and no proceeding for that purpose shall have been commenced or shall be pending or, to XM Holdings’s knowledge, threatened.

(c) Since the execution of this Agreement, there shall not have been any decrease in the rating of any debt or preferred stock of XM Holdings, the Company or any Subsidiary by any “nationally recognized statistical rating organization” (as defined for purposes of Rule 436(g) under the Act), or any notice given of any intended or potential decrease in any such rating or of a possible change in any such rating that does not indicate the direction of the possible change.

(d) No event or condition of a type described in Section 5(a)(xix)(2) hereof shall have occurred or shall exist, which event or condition is not described in each of the Pricing Disclosure Package (excluding any amendment or supplement thereto) and the Final Offering Memorandum (excluding any amendment or supplement thereto) the effect of which in the judgment of the Representative makes it impracticable or inadvisable to proceed with the offering, sale or delivery of the Securities on the terms and in the manner contemplated by this Agreement, the Pricing Disclosure Package and the Final Offering Memorandum.

(e) The Initial Purchasers shall have received on the Closing Date (i) an opinion and negative assurance letter each dated the Closing Date, addressed to the Initial Purchasers, of Skadden, Arps, Slate, Meagher & Flom LLP, counsel to the Company, substantially in the form of Exhibit A-1 attached hereto, (ii) an opinion and negative assurance letter each dated the Closing Date, addressed to the Initial Purchasers, of Hogan & Hartson L.L.P., regarding regulatory and certain corporate matters, substantially in the form of Exhibit A-2 attached hereto and (iii) an opinion dated the Closing Date, addressed to the Initial Purchasers, of Simpson Thacher & Bartlett LLP, counsel to Sirius, substantially in the form of Exhibit A-3 hereto.

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(f) The Initial Purchasers shall have received on the Closing Date an opinion and negative assurance letter dated the Closing Date of Latham & Watkins LLP, counsel to the Initial Purchasers, in form and substance satisfactory to the Representative. Such counsel shall have been furnished with such certificates and documents as they may reasonably request to enable them to review or pass upon the matters referred to in this Section 8 and in order to evidence the accuracy, completeness or satisfaction in all material respects of any of the representations, warranties or conditions contained in this Agreement.

(g) On the date hereof, the Initial Purchasers shall have received (i) a “comfort letter” from the independent public accountants for the Company, dated the date of this Agreement, addressed to the Initial Purchasers and in form and substance satisfactory to the Representative and counsel to the Initial Purchasers, covering the financial and accounting information in the Pricing Disclosure Package and (ii) a “comfort letter” from the independent public accountants for the Company, dated the date of this Agreement, addressed to the Initial Purchasers and in form and substance satisfactory to the Representative and counsel to the Initial Purchasers, covering the financial and accounting information in the Final Offering Memorandum. In addition, the Initial Purchasers shall have received a “bring-down comfort letter” from the independent public accountants for the Company, dated as of the Closing Date, addressed to the Initial Purchasers and in the form of the “comfort letter” delivered on the date hereof, except that (i) it shall cover the financial and accounting information in the Final Offering Memorandum and any amendment or supplement thereto and (ii) procedures shall be brought down to a date no more than 5 days prior to the Closing Date, and otherwise in form and substance satisfactory to the Representative and counsel to the Initial Purchasers.

(h) XM Escrow and the Trustee shall have executed and delivered the Indenture, the Company, XM Escrow and the Trustee shall have executed and delivered the Assumption Indenture and the Company, XM Escrow and the Guarantors and the Trustee shall have executed and delivered the Guarantor Indenture and the Initial Purchasers shall have received copies thereof.

(i) The Initial Purchasers shall have been furnished with wiring instructions for the application of the proceeds of the Securities in accordance with this Agreement and such other information as they may reasonably request.

(j) XM Escrow, XM Holdings, the Escrow Agent and the Trustee shall have executed and delivered the Escrow Agreement and the Initial Purchasers shall have received copies thereof. The Escrow Account shall have been established by the Escrow Agent, to the reasonable satisfaction of the Initial Purchasers. XM Holdings and the Company shall have deposited the Initial Escrow Amount into the Escrow Account and the Escrowed Funds shall be remaining in the Escrow Account. XM Escrow shall have granted, to the extent it has rights therein, a valid first priority security interest in the Escrow Account and all Escrowed Funds maintained therein in favor of the Trustee on behalf of the holders of the Senior Notes and shall have perfected such security interest to the reasonable satisfaction of the Initial Purchasers and the other conditions contained in the Escrow Agreement shall have been satisfied. The Initial Purchasers shall have received copies of such documents as they may reasonably request in connection with the foregoing.

(k) XM Escrow and the Company shall have executed and delivered the Escrow Merger Agreement and the Initial Purchasers shall have received copies thereof.

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(l) The Securities shall be eligible for trading in Portal upon issuance. All agreements set forth in the blanket representation letter of the Company to DTC relating to the approval of the Senior Notes by DTC for “book-entry” transfer shall have been complied with.

If any of the conditions specified in this Section 8 shall not have been fulfilled when and as required by this Agreement to be fulfilled (or waived by the Initial Purchasers), this Agreement may be terminated by the Initial Purchasers on notice to the Company at any time at or prior to the Closing Date, and such termination shall be without liability of any party to any other party.

The documents required to be delivered by this Section 8 will be delivered at the office of counsel for the Initial Purchasers on the Closing Date.

9. Initial Purchasers Information. XM Escrow, XM Holdings, the Company and the Initial Purchasers severally acknowledge that, for all purposes (including Sections 5(a)(i) and 6), the statements set forth in the seventh and ninth paragraphs and the fifth sentence of the tenth paragraph under “Plan of distribution” in the Preliminary Offering Memorandum and the Final Offering Memorandum constitute the only information furnished in writing by or behalf of any Initial Purchaser expressly for use in the Pricing Disclosure Package or the Final Offering Memorandum.

10. Survival of Representations and Agreements. All representations and warranties, covenants and agreements contained in this Agreement, including the agreements contained in Sections 4(f) and 11(d), the indemnity agreements contained in Section 6 and the contribution agreements contained in Section 7, shall remain operative and in full force and effect regardless of any investigation made by or on behalf of the Initial Purchasers or any controlling person thereof or by or on behalf of XM Escrow, XM Holdings, the Company or any controlling person thereof, and shall survive delivery of and payment for the Senior Notes to and by the Initial Purchasers. The agreements contained in Sections 4(f), 6, 7, 9 and 11(c) shall survive the termination of this Agreement, including pursuant to Section 11.

11. Effective Date of Agreement; Termination. This Agreement shall become effective upon execution and delivery of a counterpart hereof by each of the parties hereto.

(a) The Initial Purchasers shall have the right to terminate this Agreement at any time prior to the Closing Date by written notice to the Company from the Initial Purchasers, without liability (other than with respect to Sections 6 and 7) on the Initial Purchasers’ part to XM Holdings, the Company or any affiliate thereof if, on or prior to such date, (i) the Issuers shall have failed, refused or been unable to perform any agreement on its part to be performed under this Agreement when and as required; (ii) any other condition to the obligations of the Initial Purchasers under this Agreement to be fulfilled by the Issuers pursuant to Section 8 is not fulfilled when and as required in any material respect; (iii) trading in any securities of the Company, XM Holdings or any Subsidiary shall be suspended or limited by the Commission or The Nasdaq National Market or trading in securities generally on the New York Stock Exchange, the American Stock Exchange or The Nasdaq National Market shall have been suspended or materially limited, or minimum prices shall have been established thereon by the Commission, or by such exchange or other regulatory body or governmental authority having jurisdiction; (iv) a general moratorium shall have been declared by either Federal or New York State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States shall have occurred; (v) there is an outbreak or escalation of hostilities or national or international calamity in any case involving the United States, on or after the date of this Agreement, or if there has been a declaration by the United States of a national emergency or war or other national or international calamity or crisis (economic, political, financial or otherwise) which affects the U.S. and international markets, making it, in the Representative’s judgment, impracticable to proceed with the offering, sale or

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delivery of the Securities on the terms and in the manner contemplated in the Pricing Disclosure Package; or (vi) there shall have been such a material adverse change in general economic, political or financial conditions or the effect (or potential effect if the financial markets in the United States have not yet opened) of international conditions on the financial markets in the United States shall be such as, in the Representative’s judgment, to make it inadvisable or impracticable to proceed with the offering, sale or delivery of the Securities on the terms and in the manner contemplated in the Pricing Disclosure Package.

(b) Any notice of termination pursuant to this Section 11 shall be given at the address specified in Section 12 below by telephone or facsimile, confirmed in writing by letter.

(c) If this Agreement shall be terminated pursuant to Section 11(a), or if the sale of the Securities provided for in this Agreement is not consummated because of any refusal, inability or failure on the part of the Issuers to satisfy any condition to the obligations of the Initial Purchasers set forth in this Agreement to be satisfied or because of any refusal, inability or failure on the part of the Issuers to perform any agreement in this Agreement or comply with any provision of this Agreement, the Issuers, jointly and severally, will reimburse the Initial Purchasers for all of their reasonable out-of-pocket expenses (including, without limitation, the fees and expenses of the Initial Purchasers’ counsel) incurred in connection with this Agreement and the transactions contemplated hereby.

(d) If any one or more Initial Purchasers shall fail to purchase and pay for any of the Securities agreed to be purchased by such Initial Purchaser hereunder and such failure to purchase shall constitute a default in the performance of its or their obligations under this Agreement, the remaining Initial Purchasers shall be obligated severally to take up and pay for (in the respective proportions which the principal amount of Securities set forth opposite their names in Schedule I hereto bears to the aggregate principal amount of Securities set forth opposite the names of all the remaining Initial Purchasers) the Securities which the defaulting Initial Purchaser or Initial Purchasers agreed but failed to purchase; provided, however, that in the event that the aggregate principal amount of Securities which the defaulting Initial Purchaser or Initial Purchasers agreed but failed to purchase shall exceed 10% of the aggregate principal amount of Securities set forth in Schedule I hereto, the remaining Initial Purchasers shall have the right to purchase all, but shall not be under any obligation to purchase any, of the Securities, and if such nondefaulting Initial Purchasers do not purchase all the Securities, this Agreement will terminate without liability to any nondefaulting Initial Purchaser or the Company. In the event of a default by any Initial Purchaser as set forth in this Section 11(e), the Closing Date shall be postponed for such period, not exceeding seven Business Days, as the Representative shall determine in order that the required changes in the Final Offering Memorandum or in any other documents or arrangements may be effected. Nothing contained in this Agreement shall relieve any defaulting Initial Purchaser of its liability, if any, to the Company or any nondefaulting Initial Purchaser for damages occasioned by its default hereunder.

12. Notice. All communications with respect to or under this Agreement, except as may be otherwise specifically provided in this Agreement, shall be in writing and, if sent to the Initial Purchasers, shall be mailed, delivered or telecopied and confirmed in writing to c/o J.P. Morgan Securities Inc. 270 Park Avenue, 5^th Floor, New York, NY 10017 (fax number : 212 ###-###-####, Attention: Jessica Kearns and (ii) Latham & Watkins LLP, 885 Third Avenue, Suite 1000, New York, NY 10022 (fax number: 212 ###-###-####), Attention: Marc D. Jaffe; and if sent to the Issuers, shall be mailed, delivered or telecopied and confirmed in writing to (i) XM Satellite Radio Inc., 1500 Eckington Place, NE, Washington, DC 20002 (telephone: 202 ###-###-####, fax: 202 ###-###-####), Attention: General Counsel, (ii) with a copy for information purposes only to (a) Skadden, Arps, Slate, Meagher & Flom LLP, Four Times Square, New York, NY 10036 (fax number: 212 ###-###-####) Attention: David J. Goldschmidt (b) Sirius Satellite Radio Inc., 1221 Avenue of the Americas, 36^th Floor, New York, NY 10020 (telephone: 212 ###-###-####, fax: 212 ###-###-####), Attention: General Counsel and (c) Simpson, Thacher & Bartlett LLP, 425 Lexington Avenue, New York, NY 10017 (fax: 212 ###-###-####), Attention: Gary L. Sellers.

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All such notices and communications shall be deemed to have been duly given: when delivered by hand, if personally delivered; five business days after being deposited in the mail, postage prepaid, if mailed; when receipt acknowledged by telecopier machine, if telecopied; and one business day after being timely delivered to a next-day air courier.

13. Parties. This Agreement shall inure solely to the benefit of, and shall be binding upon, the Initial Purchasers, the Issuers and the other indemnified parties referred to in Sections 6 and 7, and their respective successors and assigns, and no other person shall have or be construed to have any legal or equitable right, remedy or claim under or in respect of or by virtue of this Agreement or any provision herein contained. The term “successors and assigns” shall not include a purchaser, in its capacity as such, of Notes from the Initial Purchasers.

14. Construction. This Agreement shall be construed in accordance with the internal laws of the State of New York (without giving effect to any provisions thereof relating to conflicts of law other than New York General Obligations Law Section 5-1401 and 5-1402).

15. Submission to Jurisdiction; Waiver of Jury Trial. No proceeding related to this Agreement or the transactions contemplated hereby may be commenced, prosecuted or continued in any court other than the courts of the State of New York located in the City and County of New York or in the United States District Court for the Southern District of New York, which courts shall have jurisdiction over the adjudication of such matters, and the Issuers hereby consent to the jurisdiction of such courts and personal service with respect thereto. The Issuers hereby waive all right to trial by jury in any proceeding (whether based upon contract, tort or otherwise) in any way arising out of or relating to this Agreement. The Issuers agree that a final judgment in any such proceeding brought in any such court shall be conclusive and binding upon the Issuers and may be enforced in any other courts in the jurisdiction of which the Issuers are or may be subject, by suit upon such judgment.

16. Captions. The captions included in this Agreement are included solely for convenience of reference and are not to be considered a part of this Agreement.

17. Counterparts. This Agreement may be executed in various counterparts that together shall constitute one and the same instrument.

18. No Fiduciary Relationship. The Issuers hereby acknowledge that the Initial Purchasers are acting solely as initial purchasers in connection with the purchase and sale of the Securities. The Issuers further acknowledge that each of the Initial Purchasers is acting pursuant to a contractual relationship created solely by this Agreement entered into on an arm’s length basis and in no event do the parties intend that any Initial Purchaser act or be responsible as a fiduciary to the Issuers, their management, stockholders, creditors or any other person in connection with any activity that such Initial Purchaser may undertake or has undertaken in furtherance of the purchase and sale of the Securities, either before or after the date hereof. The Initial Purchasers hereby expressly disclaim any fiduciary or similar obligations to the Issuers, either in connection with the transactions contemplated by this Agreement or any matters leading up to such transactions, and the Issuers hereby confirm their understanding and agreement to that effect. The Issuers and each Initial Purchaser agree that they are each responsible for making their own independent judgments with respect to any such transactions, and that any opinions or views expressed by any Initial Purchaser to the Issuers regarding such transactions, including but not limited to any opinions or views with respect to the price or market for the Securities, do not constitute advice or

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recommendations to the Issuers. The Issuers hereby waive and release, to the fullest extent permitted by law, any claims that such Issuers may have against the Initial Purchasers with respect to any breach or alleged breach of any fiduciary or similar duty to the Issuers in connection with the transactions contemplated by this Agreement or any matters leading up to such transactions.

[Signature Pages Follow]

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If the foregoing Purchase Agreement correctly sets forth the understanding among the Issuers and the Initial Purchasers, please so indicate in the space provided below for the purpose, whereupon this letter and your acceptance shall constitute a binding agreement among the Issuers and the Initial Purchasers.

Schedule I

Schedule II

Subsidiaries of XM Satellite Radio Holdings Inc.

XM Satellite Radio Inc.

XM 1500 Eckington LLC

XM Orbit LLC

XM Investments LLC

XM Escrow LLC

Subsidiaries of XM Satellite Radio Inc.

XM Radio Inc.

XM Innovations Inc.

XM Equipment Leasing LLC

XM EMall Inc.

XM Capital Resources Inc.

All of these subsidiaries are organized in the State of Delaware and are wholly owned subsidiaries.