EXHIBIT 99.1

[MOTIENT LOGO]

October 6, 2005

James D. Dondero
Highland Capital Management, L.P.
1300 Two Galleria Tower
13455 Noel Rd., LB 45
Dallas, TX 75240

Dear Jim:

The Audit Committee of Motient's Board of Directors and its independent special
counsel have concluded their investigation regarding your concerns about various
members of Motient's current and former board, certain members of management,
and certain consultants and advisors. The Committee took your allegations
against the Company and the other parties very seriously, despite the fact that
you did not present any meaningful evidence to substantiate your concerns either
prior to, or subsequent to, the commencement of this investigation. Among other
things, the Committee retained independent special counsel and, since July 2005,
has distributed written information requests to various individuals, conducted
personal follow-up interviews, and collected documentary and other evidence from
Motient. Having now concluded its investigation, the Committee has determined
that your allegations were and are completely unfounded; specifically, it found
no evidence during the course of its investigation that could reasonably lead to
the conclusion that any of your allegations had merit.

We would also remind you that, as a director of Motient, you owe all Motient
shareholders a duty to act, at all times, loyally, with due care and in good
faith to promote the best interests of those shareholders, and may not place
your own interests or those of your affiliates ahead of your duties as a Motient
director. In this regard, your inaccurate, baseless, and unsubstantiated charges
against Motient, your fellow directors and Motient's officers and advisors, and
your unsupportable disparaging comments concerning Motient's business and assets
are inconsistent with your duties as a director of Motient.(1) If you continue
to take actions detrimental to Motient and its shareholders, the Board will be
forced to take steps to protect Motient and its shareholders, and the Board
expressly reserves its rights in this regard.

Given your public statements expressing your desire to maintain shareholder
value, we hope, in light of the Committee's findings, that you will now promptly
dismiss your various lawsuits to avoid further wasting of corporate assets and
destruction of shareholder value by forcing Motient and its directors and
officers to spend time, energy, and resources investigating your unsubstantiated
claims and defending against your suits, rather than carrying out the business
of Motient.

- -----------------------------------
(1) As a reminder, when the company requests you to disclose to it litigation
that you or your affiliates have been involved in, please note that your duty of
honesty requires you to disclose all such litigation. We have noticed that you
or your affiliates (including Highland) have been involved in far more lawsuits
than you previously reported. Please see Exhibit A for a list of representative
cases, which is by no means comprehensive.

In addition, we urge you to correct all inaccurate statements and factual errors
you have publicly made regarding Motient. Here are a few examples of such
inaccuracies, but this list is by no means exhaustive:

1. Contrary to your assertions, MSV does, in fact, have audited financial
statements (audited by a Big Four accounting firm). These financial
statements are publicly available in Motient's most recent 10-K, which
you signed.
2. Contrary to your contention, MSV does, in fact, have access to the
public markets other than through Motient. Motient is not the only
public investor in MSV.
3. Highland and its affiliates do not, in fact, "own approximately 14% of
the outstanding Common Stock of Motient Corporation." Highland owns
far less than 14% of Motient's outstanding common stock, and a
substantial portion of Highland's ownership used in that calculation
seems to include securities that are not outstanding common stock,
such as preferred stock and warrants.
4. Motient's board did, in fact, discuss the proposed acquisition of MSV
and TerreStar and authorized management to bring a final deal to the
full board for their approval. Although you declined to attend these
meetings, you did receive written materials and even sent a
representative to observe the meeting. As you know, the securities
laws restrict our ability to discuss this transaction any further in
this forum. Motient's shareholders will have the opportunity to fully
review the matter, however, in the event that the board approves the
transaction and consequently submits the deal to the shareholders for
their approval.

On a final note, the nominating committee reports that you have not cooperated
with them in their requests for information concerning your conversations with
Motient stockholders in which you may have disclosed material, non-public
information that you obtained in your role as a member of Motient's board of
directors. The other members of the board and management participated in the
audit committee investigation instigated at your request, and we expect a
similar level of cooperation from you with the nominating committee. Given
certain third-party claims made against you regarding your desire or intent to
misuse confidential inside information (see, e.g., Joshua Wheelock v. Highland
Capital Management, LP and James Dondero, Case No. 04cv09289, filed in the
United States District Court for the Southern District of New York), the
nominating committee would like to resolve this matter as soon as possible and
your full cooperation is required to do so. In any event, we would advise you
not to share any undisclosed transaction information with third-parties. We also
caution our investors not to potentially hinder their trading capabilities by
taking any meeting with you where material nonpublic information may be shared.

Sincerely,

Motient Corporation

cc: Board of Directors, Motient Corporation

300 KNIGHTSBRIDGE PARKWAY
LINCOLNSHIRE, ILLINOIS 60069-3625
PHONE 847.478.4200
FAX 847.478.4810

EXHIBIT A

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No. Name Case No. Location Date Filed
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1. American Express v. James Dondero 02-01218-E Dallas Co. Court at Law, 1/28/2002
TX
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2. Anthony H.N. Schnelling, as Trustee of the 04mc00096 N.D. Tex., TX 11/12/2004
Bankruptcy Estate of Epic Restorts LLC v.
Prudential Securities
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3. Bank of America,N.A. v. The Bank of New York Co., 04-053890 D. Del., DE. (adversary) 6/9/2004
Inc.
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4. Charlesbank Partners LLC v. Highland Capital 05-02015 S.D. Tex, TX (adversary) 2/19/2005
Management L.P.
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5. Daniel Jara v. Highland Capital Management 04-11790 Dallas Co. District 11/22/2004
Services, Inc. Court, TX
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6. Dondero v. American Express TRS 0504896D Dallas Co. District 4/19/2005
Court, TX
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7. Dondero v. Jackson 9802681B Dallas Co. District 03/17/1998
Court, TX
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8. Dondero v. Lien Ho Van Nlim Tran LS 1156 LA County, CA 02/25/1991
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9. Dondero v. Refco Sec. Inc. 00:mc:00037 N.D. Tex., TX 4/28/2000
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10. Freeport Partners LLC v. John J. Arlotta 601733/04 Supreme Court of New 6/14/2004
York, NY
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11. General Electric Capital Corp. v. Trussway 2:2005cv0046 S.D. Tex., TX 1/31/2005
Industries
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12. General Electric Capital Corp. v. Trussway 2:2005cv0084 S.D. Tex., TX 2/17/2005
Industries
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13. Harch Capital Management, Highland Capital 99-cv-1350 S.D. Fla., FL 05/12/1999
Management v. Skandinaviska Enskilda Banken AB
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14. Heilig-Meyers Co. v. Wachovia Bank 02-6158 E.D. Va., VA (adversary) 7/29/2002
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15. Highland Capital Management v. Carlyle Partners 04C-06-068 New Castle County, DE 06/04/2004
II LP
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16. Highland Capital Management v. Chesapeake Energy 4:2004cv00787 S.D. Tex., TX 2/27/2004
Co.
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17. Highland Capital Management v. Ernst & Young 5L 8372 Cook County, IL 7/29/2005
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18. Highland Capital Management v. Ernst & Young and 03-04530-K Dallas Co. District 5/19/2003
TC Group, L.L.C. d/b/a The Carlyle Group, L.P. Court, TX
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19. Highland Capital Management v. Financial Tracking 05-04050-I Dallas Co. District 4/26/2005
Technologies, LLC Court, TX
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20. Highland Capital Management v. GE On Wing 02-cv-02771- E.D.N.Y. 05/08/2002
Support, Inc. RJD-MDG
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21. Highland Capital Management v. Global Aerospace 02-cv-09360 S.D.N.Y. 11/22/2002
Underwriting Managers Ltd.
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22. Highland Capital Management v. Grant Thornton LLP 02-1499-E Dallas Co. District 2/15/2002
Court, TX
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23. Highland Capital Management v. KPMG, LLP 03-5643-B Dallas Co. District 6/4/2003
Court, TX
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24. Highland Capital Management v. Moll Industries 03-05021-rbk W.D. Tex. 02/19/2003
(adversary)
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25. Highland Capital Management v. Prudential 03-01019-J Dallas Co. District 1/31/2003
Securities Inc. Court, TX
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26. Highland Capital Management v. Ryder Scott Company 04-03708 S.D. Tex., TX 08/24/2004
(adversary)
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27. Highland Capital Management v. Schneider 02-CV-08098- S.D.N.Y, NY 10/11/2002
PKL-GWG
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28. Highland Capital Management v. Scott P. Peltz, as 4:2005cv00957 E.D. Mo, MO 6/14/2005
Chapter 11 Plan Administrator for BIS
Administration, Inc.
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29. Highland Capital Management, L.P. v. Seven Seas 4:2005cv01073 S.D. Tex., TX 3/29/2005
Petrolem Inc.
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30. Highland Capital Management, L.P. v. Seven Seas 4:2005cv01104 S.D. Tex., TX 4/1/2005
Petrolem Inc.
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31. Highland Capital Management v. Thomas H. Lee 1:03cv440-GMS D. Del, DE 4/29/2003
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32. Highland Capital Management v. Votis 04-05053-rbk W.D. Tex., TX 04/05/2004
(adversary)
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33. Highland Capital Management v. Welsh Carson 03-04662 E.D. Mo. 09/24/2002
Anderson & Stowe (adversary)
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34. Highland Capital Management v. Welsh Carson 03-04662 E.D. Mo., MO (adversary) 7/3/2003
Anderson & Stowe
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35. Highland Legacy Ltd v. Singer, et al. 1566-N New Castle County, DE 8/16/2005
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36. In re James Dondero 3:00mc037 N.D. Tex, TX 4/28/2000
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37. Jefferies & Co., Inc. v. Highland Capital 99-05387 Dallas Co. District 7/16/1999
Management, L.P. Court, TX
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38. Joshua Wheelock v. Highland Capital Management, 04cv09289 S.D.N.Y. (Foley Square), 11/24/2004
LP and James Dondero NY
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39. Moll Industries, Inc. and Highland Capital 04-5053-K W.D. Tex., TX 4/5/2004
Management, L.P. v. George T. Votice (adversary)
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40. Official Committee of Unsecured Creditors of 04-01083 S.D.N.Y, NY 1/20/2004
Galey & Lord, Inc. v. Wachovia Securities, Inc.
as Agent for Pre-petition Lenders, Highland
Capital Management, L.P., GE Capital, Barclays
Bank Plc., Barclays and Sun Trust Bank
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41. PAM Capital Funding, Highland Legacy Ltd. v. BBC 0200423L Dallas Co. District 1/16/2002
Distribution LLC Court, TX
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42. PAM Capital Funding, Highland Legacy, Ltd. v. 0302248I Dallas Co, District 03/13/2003
Banks Corporation Court, TX
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43. Pam Capital Funding, Highland Legacy, Ltd. v. 02-04024-bjh N.D. Tex., TX 02/15/2003
National Gypsum Co. (adversary)
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44. Pam Capital Funding, Highland Legacy Ltd. v. New 03-04181-bjh N.D. Tex., TX 04/09/2003
NGC, Inc. (adversary)
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45. Richard Haskell v. Goldman, Sachs & Co. 04-53375 D. Del., DE (adversary) 5/3/2004
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46. Richard C. Jakob v. Highland Capital Management, 03-12313-D Dallas Co. District 11/20/2003
L.P. and Strand Advisors, Inc. Court, TX
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47. SAVVIS Communications Corp. v. Highland Capital 02-04345 E.D. Missouri 11/25/2002
Management, L.P. (adversary), MO
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48. Thomas H. Lee v. Highland Capital Management 02-05951-RTL D. Del, DE. (adversary) 10/16/2002
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49. Thomas H. Lee v. Highland Capital Management 1:03cv441-GMS D. Del., DE 4/29/2003
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50. Thomas Schutze v. Fin. Computer Software, L.P. 04cv0276 N.D. Tex., TX
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51. In the Matter of Tradewinds Financial Corp. v. 99cv2268 S.D.N.Y, NY
REFCO Securities, Inc.
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52. In re Video Update, Inc. 1:2002cv01370 D. Del., DE 8/9/2002
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53. Welsh Carson Anderson & Stowe v. Highland Capital 03-04577-293 E.D. Mo., MO 5/8/2003
Management
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