EXHIBIT 99.2 AMERICAN MOBILE SATELLITE CORPORATION AMSC ACQUISITION COMPANY, INC. NOTICE OF GUARANTEED DELIVERY FOR TENDER OF ANY AND ALL OF THE OUTSTANDING SERIES A 12 1/4 % SENIOR NOTES DUE 2008 OF AMSC ACQUISITION COMPANY, INC. FULLY AND UNCONDITIONALLY GUARANTEED BY (i) AMERICAN MOBILE SATELLITE CORPORATION ON A SUBORDINATED UNSECURED BASIS, (ii) ALL CURRENT AND FUTURE SUBSIDIARIES OF AMSC ACQUISITION COMPANY. This Notice of Guaranteed Delivery, or one substantially equivalent to this form, must be used to accept the Exchange Offer (as defined below) if (i) certificates for the Company's (as defined below) Series A 12 1/4 % Senior Notes Due 2002 (the "Notes") are not immediately available, (ii) Old Notes, the Letter of Transmittal and all other required documents cannot be delivered to State Street Bank and Trust Company ("Exchange Agent") on or prior to the Expiration Date (as defined in the Prospectus referred to below) or (iii) the procedures for delivery by book-entry transfer cannot be completed on a timely basis. This Notice of Guaranteed Delivery may be delivered by hand, overnight courier or mail, or transmitted by facsimile transmission, to the Exchange Agent on or prior to the Expiration Date. See "The Exchange Offer - Procedures for Tendering" in the Prospectus. In addition, in order to utilize the guaranteed delivery procedure to tender Old Notes pursuant to the Exchange Offer, a completed, signed and dated Letter of Transmittal relating to the Old Notes (or facsimile thereof) must also be received by the Exchange Agent prior to 5:00 p.m., New York City time, on the Expiration Date. Capitalized terms used but not defined herein have the meanings given them in the Prospectus. THE EXCHANGE AGENT FOR THE EXCHANGE OFFER IS: STATE STREET BANK AND TRUST COMPANY BY REGISTERED OR CERTIFIED BY HAND OR OVERNIGHT COURIER: BY HAND IN BOSTON: BY HAND OR OVERNIGHT COURIER IN Mail: NEW YORK (AS DROP AGENT): STATE STREET BANK STATE STREET BANK STATE STREET BANK STATE STREET BANK AND TRUST COMPANY AND TRUST COMPANY AND TRUST COMPANY AND TRUST COMPANY N.A. P.O. BOX 778 TWO INTERNATIONAL PLACE TWO INTERNATIONAL PLACE 61 BROADWAY BOSTON, MASSACHUSETTS 02102 BOSTON, MASSACHUSETTS 02110 FOURTH FLOOR, CORPORATE TRUST FIFTEENTH FLOOR, CORPORATE TRUST DEPARTMENT CORPORATE TRUST DEPARTMENT BOSTON MASSACHUSETTS 02110 CORPORATE TRUST WINDOW ATTENTION: KELLIE MULLEN ATTENTION: KELLIE MULLEN NEW YORK, NEW YORK 10006 To confirm by telephone or for information call: (617) 664-5587 DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE OR TRANSMISSION OF THIS NOTICE OF GUARANTEED DELIVERY VIA FACSIMILE TO A NUMBER OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY. THIS NOTICE OF GUARANTEED DELIVERY IS NOT TO BE USED TO GUARANTEE SIGNATURES. IF A SIGNATURE ON A LETTER OF TRANSMITTAL IS REQUIRED TO BE GUARANTEED BY AN "ELIGIBLE INSTITUTION" UNDER THE INSTRUCTIONS THERETO, SUCH SIGNATURE GUARANTEE MUST APPEAR IN THE APPLICABLE SPACE PROVIDED IN THE SIGNATURE BOX ON THE LETTER OF TRANSMITTAL. Ladies and Gentlemen: The undersigned hereby tenders to AMSC Acquisition Company, a Delaware corporation (the "Company"), upon the terms and subject to the conditions set forth in the Prospectus dated May ____, 1998 (as the same may be amended or supplemented from time to time, the "Prospectus"), and the related Letter of Transmittal (which together constitute the "Exchange Offer"), receipt of which is hereby acknowledged, the aggregate principal amount of Old Notes set forth below pursuant to the guaranteed delivery procedures set forth in the Prospectus under the caption "The Exchange Offer -- Guaranteed Delivery Procedures." Aggregate Principal Amount Tendered: $____________________ Name(s) of Registered Holder(s):____________________________ ______________________________________ Certificate No.(s)(if available):_____ ______________________________________ If Old Notes will be tendered by book-entry Entry Transfer, provide the following information DTC Account Number:___________________ Date__________________________, 1998 All authority herein conferred or agreed to be conferred in this Notice of Guaranteed Delivery shall survive the death, incapacity or dissolution of the undersigned and any obligation of the undersigned hereunder shall be binding upon the heirs, executors, administrators, personal representatives, trustees in bankruptcy, legal representatives, successors and assigns of the undersigned. PLEASE SIGN HERE: _________________________________ (Signature(s) of Owner(s) or Authorized Signatory) ____________________________, 1998 ____________________________, 1998 Area Code and Telephone number :_________________ - -------------------------------------------------------------------------------- Must be signed by the holder(s) of the Old Notes exactly as their name(s) appear(s) on certificate(s) for the Old Notes or on a security position listing, or by person(s) authorized to become registered holder(s) by endorsements and documents transmitted with this Notice of Guaranteed Delivery. If signature is by an attorney-in-fact, executor, administrator, trustee, guardian, officer of a corporation or other person acting in a fiduciary or representative capacity, please set forth the signer's full title. Please print name(s) and address(es) Names:_____________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Capacity:___________________________________________________________________ Address:____________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ - -------------------------------------------------------------------------------- THE GUARANTEE ON THE REVERSE SIDE MUST BE COMPLETED. - -------------------------------------------------------------------------------- GUARANTEE (NOT TO BE USED FOR SIGNATURE GUARANTEE) The undersigned, a firm or other entity identified in Rule 17Ad-15 under the Securities Exchange Act of 1934, as amended, as an "eligible guarantor institution," including (as such terms are defined therein): (i) a bank; (ii) a broker, dealer, municipal securities broker, municipal securities dealer, government securities broker or government securities dealer; (iii) a credit union; (iv) a national securities exchange, registered securities association or clearing agency; or (v) a savings association that is a participant in a Securities Transfer Association recognized program (each of the foregoing being referred to as an "Eligible Institution"), hereby guarantees to deliver to the Exchange Agent, at one of its addresses set forth above, either the Old Notes tendered hereby in proper form for transfer, or confirmation of the book-entry transfer of such Old Notes to the Exchange Agent's account at The Depository Trust Company ("DTC"), pursuant to the procedures for book-entry transfer set forth in the Prospectus, in either case together with one or more properly completed and duly executed Letter(s) of Transmittal (or facsimile thereof) and any other required documents within five business days after the date of execution of this Notice of Guaranteed Delivery. The undersigned acknowledges that it must deliver the Letter(s) of Transmittal (or facsimile thereof) and the Old Notes tendered hereby to the Exchange Agent within the time period set forth above and that failure to do so could result in a financial loss to the undersigned. ___________________________________ _____________________________________ Name of Firm Authorized Signature ___________________________________ Name:________________________________ Address (Please Type or Print) ___________________________________ Title_________________________________ (Zip Code) ___________________________________ Date:_________________________________ Area code and telephone number - -------------------------------------------------------------------------------- NOTE: DO NOT SEND CERTIFICATES FOR OLD NOTES WITH THIS NOTICE OF GUARANTEED DELIVERY. ACTUAL SURRENDER OF OLD NOTES MUST BE MADE PURSUANT TO, AND BE ACCOMPANIED BY A PROPERLY COMPLETED AND DULY EXECUTED LETTER OF TRANSMITTAL AND ANY OTHER REQUIRED DOCUMENTS.