Exhibit 10.21

EXCLUSIVE EQUITY INTEREST PURCHASE AGREEMENT

This Exclusive Equity Interest Purchase Agreement (the “Agreement”) is entered into by and among the following parties effective as of May 18, 2010 in Beijing.

WHEREAS, Party B holds a 100% equity interest in Party C (the “Equity Interest”);

WHEREAS, Party C and Party A have entered into an Exclusive Technical Consulting and Service Agreement and other agreements.

NOW THEREFORE, intending to be bound hereby and for good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the Parties hereto agree as follows:

ARTICLE I

TRANSFER OF EQUITY INTEREST

Party B hereby irrevocably grants Party A the exclusive right to purchase or designate one or more persons (the “Specified Person”) to purchase all or any portion of the Equity Interest from Party B, subject to compliance with legal restrictions under applicable PRC laws (the “Purchase Right”). Party B shall not sell or transfer all or any portion of the Equity Interest to any party other than Party A and/or the Specified Person. Party C hereby acknowledges that Party B may grant the Purchase Right to Party A, and the other shareholders of Party C have already agreed to waive any rights to acquire the Equity Interest of Party C from

Party B and such shareholders have executed the Announcement Letter to waive their pre-emptive rights (attached as Appendices). As used in this Agreement, the term “person” refers to an individual, corporation, joint enterprise, partnership, enterprise, trust or non-corporation organization.

Compliance with PRC laws and regulations are conditions precedent to exercise of the Purchase Right by Party A. To the extent Party A wishes to exercise the Purchase Right, it shall issue a written notice (the “Purchase Notice”) to Party B, and the Purchase Notice shall state: (a) that Party A intends to exercise the Purchase Right; (b) the percentage of the Equity Interest to be purchased therewith; and (c) the effective date or transfer date.

The transfer fee (“Transfer Fee”) payable by Party A shall be equal to the audited value of the net assets of Party C on April 30, 2010.

Each time Party A exercises the Purchase Right:

ARTICLE II

COVENANTS RELATING TO THE EQUITY INTEREST

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ARTICLE III

REPRESENTATIONS AND WARRANTIES

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ARTICLE IV

EFFECTIVE DATE

ARTICLE V

GOVERNING LAW AND DISPUTE SETTLEMENT

This Agreement shall be governed by and interpreted according to the laws of the PRC.

The Parties shall negotiate in good faith to settle any dispute relating to the interpretation or implementation of this Agreement. To the extent such dispute cannot be settled within thirty (30) days from the date a Party first issues written notice requesting settlement of a dispute through negotiation, either Party may submit the dispute to the China International Economic and Trade Arbitration Committee for arbitration according to the requisite arbitration rules. The arbitration shall be held in Beijing. The arbitration proceedings shall be conducted in Chinese. The arbitration award is final and binding on each party.

ARTICLE VI

TAX AND EXPENSES

ARTICLE VII

NOTICE

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ARTICLE VIII

CONFIDENTIALITY

ARTICLE IX

FURTHER ASSURANCE

ARTICLE X

MISCELLANEOUS

Any revision to, amendment of or supplement to this Agreement must be in writing and be executed by each Party hereto.

The Parties shall comply with all applicable laws and regulations which have been formally issued.

Unless it is otherwise revised, amended or supplemented, this Agreement and its appendices constitute the entire agreement among the Parties as to the subject matter of this Agreement, and supersede any prior oral or written negotiations, statements or agreements among the parties relating thereto.

Headings in this Agreement are only used for reading convenience, and shall not be used to interpret, explain or otherwise influence the meaning of the provisions of this Agreement.

This Agreement is made in Chinese and English in one or more original or facsimile counterparts. The Chinese version will prevail in the event of any inconsistency between the English and any Chinese translations thereof.

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If any of the terms of this Agreement is declared invalid, illegal or unenforceable in accordance with any applicable laws or regulations, the validity and enforceability of the other terms hereof shall nevertheless remain unaffected. The Parties hereto agree to negotiate to restructure such invalid, illegal or unenforceable terms so as to maintain the same or similar economic impact.

This Agreement shall bind the permitted transferee or successor of each Party and shall be interpreted for its benefit.

Each Party may waive the terms and conditions under this Agreement in writing. Such waiver must be duly signed by such Party. Any waiver relating to the breach of the other Party in certain circumstance shall not be deemed as a waiver for a similar breach in other circumstances.

[Remainder of Page Left Intentionally Blank – Signature Page Follows]

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[Equity Interest Purchase Agreement – Satellite – Signature Page]

IN WITNESS WHEREOF, the Parties have executed this Agreement on the date first above written.

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Appendix 1

Announcement Letter

Beijing Satellite Science & Technology Co. Ltd. (the “Company”) is a limited liability company established on October 11, 1994 and validly existing under the laws of the PRC. I, as a shareholder of the Company, hold a 70 % equity interest in the Company. I, together with the other shareholder, Ma Hongzhi collectively hold a 100% equity interest in the Company. I hereby irrevocably waive any pre-emptive right I may have upon the other 30% equity interest in the Company and will not encumber the transfer of the equity interest you proposed in any way.

This Announcement Letter is effective as of May 18, 2010.

Appendix 2

Announcement Letter

Beijing Satellite Science & Technology Co. Ltd. (the “Company”) is a limited liability company established on October 11, 1994 and validly existing under the laws of the PRC. I, as a shareholder of the Company, hold a 30 % equity interest in the Company. I, together with the other shareholder, Cheng Guang collectively hold a 100% equity interest in the Company. I hereby irrevocably waive any pre-emptive right I may have upon the other 30% equity interest in the Company and will not encumber the transfer of the equity interest you proposed in any way.

This Announcement Letter is effective as of May 18, 2010.