AMENDMENT
      NO. 1

    TO

    SECURITIES
      PURCHASE AGREEMENT

     

    AMENDMENT
      NO. 1 TO SECURITIES PURCHASE AGREEMENT, dated as of January 7, 2008 (this
“Amendment”),
      by
      and among MOBILE SATELLITE VENTURES LP, a Delaware limited partnership
      (“MSV”),
      MOBILE SATELLITE VENTURES FINANCE CO., a Delaware corporation (“MSV
      Finance Co.”
and,
      together with MSV, the “Issuers”),
      SKYTERRA COMMUNICATIONS INC., a Delaware corporation, HARBINGER CAPITAL PARTNERS
      MASTER FUND I, LTD., a Cayman Islands fund, and HARBINGER CAPITAL PARTNERS
      SPECIAL SITUATIONS FUND, LP, a Delaware limited partnership (collectively,
      the
“Purchasers”).

     

    WITNESSETH:

     

    WHEREAS,
      the Issuers and the Purchasers are parties to that certain Securities Purchase
      Agreement, dated as of December 15, 2007 (the “Purchase
      Agreement”);
      and

     

    WHEREAS,
      in accordance with Section 9.11 of the Purchase Agreement, the Issuers and
      the Purchasers wish to amend the Purchase Agreement as provided
      herein.

     

    NOW,
      THEREFORE, in consideration of the mutual promises herein set forth, and other
      good and valuable consideration, the receipt and sufficiency of which are hereby
      acknowledged, the parties hereto agree as follows:


     

    ARTICLE
      I

     

    AMENDMENT
      TO PURCHASE AGREEMENT

     

    1.1 Amendment
      to Article 3 of the Purchase Agreement. The second sentence of Section 3.1(b)
      of
      the Purchase Agreement shall be amended to read in its entirety as
      follows:

     

    “The
      parties agree to cooperate in good faith to determine the allocation between
      the
      Notes and the Warrants within ten (10) days of the Closing Date.”

    


    1.2 Amendment
      to Article 8 of the Purchase Agreement.
      Article
      8 of the Purchase Agreement is hereby amended by adding the following new
      Section 8.8 following at the end thereof:

     

    “8.8 Affirmative
      Covenants.
      Prior
      to the earlier of (i) December 31, 2011, and (ii) such time that the Purchasers
      and their Affiliates cease to beneficially own at least 5% of the outstanding
      Common Stock (as defined in the Purchase Agreement), without the prior consent
      of the Purchasers:

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

     

    (a) MSV
      will
      cause all properties used or useful in the conduct of its business or the
      business of any Significant Subsidiary (as defined in the Indenture by and
      between the Issuers, the Bank of New York as Trustee and the Guarantors named
      therein dated as of January 4, 2008) to be maintained and kept in good
      condition, repair and working order and supplied with all necessary equipment
      and will cause to be made all necessary repairs, renewals, replacements,
      betterments and improvements thereof, all as in the judgment of MSV may be
      reasonably necessary so that the business carried on in connection therewith
      may
      be properly and advantageously conducted at all times; provided,
      however,
      that
      nothing in this Section
      8.8(a)
      shall
      prevent MSV or any Significant Subsidiary from (i) discontinuing the use,
      operation or maintenance of any of such properties or disposing of any of them,
      if such discontinuance or disposal is, in the judgment of MSV, desirable in
      the
      conduct of its business or the business of any such Significant Subsidiary
      or
      (ii) effectuating an Asset Disposition (as defined in the Indenture).


     

    (b) MSV
      shall
      comply, and shall cause each of its Significant Subsidiaries (as defined in
      the
      Indenture) to comply, with all applicable statutes, rules, regulations, orders
      and restrictions of the United States of America, all states and municipalities
      thereof, and of any governmental department, commission, board, regulatory
      authority, bureau, agency and instrumentality of the foregoing, in respect
      of
      the conduct of their respective businesses and the ownership of their respective
      properties, except for such noncompliances as are not in the aggregate
      reasonably likely to have a material adverse effect on the financial condition
      or results of operations of MSV and its Significant Subsidiaries taken as a
      whole.

     

    1.3 Effect
      on the Purchase Agreement.
      This
      Amendment shall not constitute a waiver, amendment or modification of any
      provision of the Purchase Agreement not expressly referred to herein. Except
      as
      expressly amended or modified herein, the provisions of the Purchase Agreement
      are and shall remain in full force and effect and are hereby ratified and
      confirmed. On and after the date hereof, each reference in the Purchase
      Agreement to “this Agreement,” “herein,” “hereof,” “hereunder” or words of
      similar import shall mean and be a reference to the Purchase Agreement as
      amended hereby. To the extent that a provision of this Amendment conflicts
      with
      or differs from a provision of the Purchase Agreement, such provision of this
      Amendment shall prevail and govern for all purposes and in all respects.


     

    ARTICLE
      II


     

    MISCELLANEOUS

     

    2.1 GOVERNING
      LAW.
      THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS
      OF
      THE STATE OF NEW YORK.

     

    2.2 Counterparts.
      This
      Amendment may be executed in any number of counterparts, and each counterpart
      shall constitute an original instrument, but all of such separate counterparts
      shall constitute one and the same agreement. The counterparts of this Amendment
      may be executed and delivered by facsimile transmitted by any of the parties
      to
      any other party and the receiving party may rely on the receipt of such document
      so executed and delivered by facsimile as if the original had been
      received.

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    2.3 Sections and
      Headings.
      The
      headings used in this Amendment are inserted for convenience of reference only
      and are not intended to be a part of or to affect the meaning or interpretation
      of this Amendment.

     

    2.4 Assignment.
      The
      rights and obligations of any party hereto shall inure to the benefit of and
      shall be binding upon the authorized successors and permitted assigns of such
      party. None of the Issuers or the Purchasers may assign this Amendment or any
      rights or obligations hereunder without the prior written consent of the other;
      provided, however, that the each of Purchasers may assign this Amendment in
      whole or in part to one or more Affiliates (as defined in the Purchase
      Agreement) of the Purchasers, whether presently existing or hereinafter created
      by providing notice in writing to the Issuers. 

     

    [Remainder
      of Page Intentionally Left Blank]

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    



    IN
      WITNESS WHEREOF, the undersigned have executed, or have caused to be executed,
      this Amendment on the date first written above.

     

    
      	 	 	 
	 	MOBILE SATELLITE VENTURES LP
              by its
              general partner, Mobile Satellite Ventures GP Inc.
	 
 	 
 	 
 
	 	By:  	/s/ Scott
              Macleod
	 	
              
Name: Scott
              Macleod
	 	Title: Executive
              Vice President and Chief
              Financial Officer


    

    
      	 	 	 
	 	 
	 	MOBILE SATELLITE VENTURES FINANCE
              CO.
	 
 	 
 	 
 
	 	By:  	/s/ Scott
              Macleod
	 	
              
Name: Scott
              Macleod
	 	Title: Executive
              Vice President and Chief Financial
              Officer


    

    
      	 	 	 
	 	 	 
	 	SKYTERRA COMMUNICATIONS,
              INC.
	 
 	 
 	 
 
	 	By:  	/s/ Scott
              Macleod
	 	
              
Name: Scott
              Macleod
	 	
              Title: Executive
                Vice President, Chief
                Financial Officer and
                Treasurer

            


    

    
 

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    

    
      	 	 	 
	 	
              HARBINGER
                CAPITAL PARTNERS MASTER FUND I, LTD.

            
	 	
              By:
                Harbinger Capital Partners Offshore Manager, L.L.C., as investment
                manager

            
	 
 	 
 	 
 
	 	By:  	/s/ William
              R. Lucas, Jr.
	 	
              

              Name: William
                R. Lucas, Jr.

            
	 	Title: Executive
              Vice President


    

    
      	 	 	 
	 	 	 
	 	
              HARBINGER
                CAPITAL PARTNERS SPECIAL SITUATIONS FUND, LP

            
	 	By: Harbinger Capital Partners
              Special
              Situations GP, LLC, as general partner
	 
 	 
 	 
 
	 	By:  	/s/ William
              R. Lucas, Jr.
	 	
              
Name: William
              R. Lucas, Jr.
	 	Title: Executive
              Vice President