Highland Sends Letter to Motient Stockholders Criticizing Proposed Director Slate and Transaction with SkyTerra; Calls on Fellow Stockholders to Replace Motient's Board of Directors.

DALLAS -- Highland Capital Management, L.P. announced today that it is mailing the following letter to Motient Corporation (PINK: MNCP) stockholders criticizing Motient's proposed transaction with SkyTerra Communications, Inc. (OTCBB: SKYT):

May 24, 2006

Dear Fellow Motient Stockholder:

As you are probably aware, Highland Capital Management, L.P. and its affiliates ("Highland") are seeking to replace the current Board of Directors of Motient Corporation ("Motient") with a full slate of experienced, ethical, and independent directors who will bring in new management and achieve the greatest value and best use of Motient's assets for the benefit of all Motient stockholders. Highland is asking for your support.

Motient recently announced that five of its existing directors, including the current Chairman, will not be standing for re-election at the upcoming annual meeting of stockholders. Motient also announced its six director candidates for election at the annual meeting. We believe that these announcements are in response to actions we have taken to publicize the degree to which Motient is being mismanaged and to effectuate change at the Motient Board level. However, we do not believe that the outgoing directors, given their past actions, should be trusted to act in the stockholders' best interest in selecting a new slate to manage Motient. It appears to us highly unlikely that the election of such a slate would put an end to Motient's long history of mismanagement, particularly since senior management will remain the same.

Shortly after its announcements regarding directors, Motient announced that it had entered into definitive agreements with SkyTerra Communications, Inc. ("SkyTerra") to consolidate the ownership and control of Mobile Satellite Ventures, LP ("MSV") and its general partner under SkyTerra, and to increase Motient's ownership of TerreStar Networks, Inc. ("TerreStar"). For reasons set forth below, we believe this proposed consolidation transaction is not in the best interest of Motient stockholders and is certainly not an appropriate action for Motient's current "lame duck" Board. This proposed transaction will significantly impact the future of Motient for all stockholders -- a future of which the outgoing directors who proposed this deal have signaled they want no part.