SC 13D/A

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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934
(Amendment No. 23 )*

Motient Corporation

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

619908304

(CUSIP Number)

J. Kevin Ciavarra
Highland Capital Management, L.P.
Two Galleria Tower
13455 Noel Road, Suite 800
Dallas, Texas 75240
(972) 628-4100

(Name, Address and Telephone Number of Person Authorized to
Receive Notices and Communications)

June 13, 2006

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. o

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

CUSIP No. 619908304  Page 2  of  15 

1	NAMES OF REPORTING PERSONS: Prospect Street High Income Portfolio, Inc.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	04-3028343
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Maryland
		7	SOLE VOTING POWER:
NUMBER OF			1,155,224
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			1,155,224
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	1,155,224
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	1.8%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	CO/IV

CUSIP No. 619908304  Page 3  of  15 

1	NAMES OF REPORTING PERSONS: Prospect Street Income Shares Inc.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	36-2765811
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Maryland
		7	SOLE VOTING POWER:
NUMBER OF			111,940
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			111,940
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	111,940
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	0.2%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	CO/IV

CUSIP No. 619908304  Page 4  of  15 

1	NAMES OF REPORTING PERSONS: Highland Legacy Limited
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Cayman Islands
		7	SOLE VOTING POWER:
NUMBER OF			223,880
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			223,880
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	223,880
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	0.4%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	OO

CUSIP No. 619908304  Page 5  of  15 

1	NAMES OF REPORTING PERSONS: Highland Crusader Offshore Partners, L.P.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Bermuda
		7	SOLE VOTING POWER:
NUMBER OF			5,352,497
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			5,352,497
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	5,352,497
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	8.6%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	PN

CUSIP No. 619908304  Page 6  of  15 

1	NAMES OF REPORTING PERSONS: PAMCO Cayman, Limited
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Cayman Islands
		7	SOLE VOTING POWER:
NUMBER OF			223,880
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			223,880
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	223,880
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	0.4%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	OO

CUSIP No. 619908304  Page 7  of  15 

1	NAMES OF REPORTING PERSONS: Highland Equity Focus Fund, L.P.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	46-0491961
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Delaware
		7	SOLE VOTING POWER:
NUMBER OF			1,518,779
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			1,518,779
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	1,518,779
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	2.4%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	PN

CUSIP No. 619908304  Page 8  of  15 

1	NAMES OF REPORTING PERSONS: Highland Select Equity Fund, L.P.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Delaware
		7	SOLE VOTING POWER:
NUMBER OF			119,283
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			119,283
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	119,283
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	0.2%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	PN

CUSIP No. 619908304  Page 9  of  15 

1	NAMES OF REPORTING PERSONS: Highland Capital Management Services, Inc.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY): 75-2911984
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Delaware
		7	SOLE VOTING POWER:
NUMBER OF			182,748
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			182,748
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	182,748
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	0.3%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	CO

CUSIP No. 619908304  Page 10  of  15 

1	NAMES OF REPORTING PERSONS: Highland Capital Management, L.P.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	75-2716725
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	AF/WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Delaware
		7	SOLE VOTING POWER:
NUMBER OF			8,822,764
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			8,822,764
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	8,822,764
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	14.1%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	IA/PN

CUSIP No. 619908304  Page 11  of  15 

1	NAMES OF REPORTING PERSONS: Strand Advisors, Inc.
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	95-4440863
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	Delaware
		7	SOLE VOTING POWER:
NUMBER OF			8,822,764
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			8,822,764
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	8,822,764
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	14.1%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	CO

CUSIP No. 619908304  Page 12  of  15 

1	NAMES OF REPORTING PERSONS: James Dondero
	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a)   þ
	(b)   o
3	SEC USE ONLY:
4	SOURCE OF FUNDS (SEE INSTRUCTIONS):
	AF/PF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION:
	United States
		7	SOLE VOTING POWER:
NUMBER OF			9,024,326
SHARES		8	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0
EACH		9	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			9,024,326
WITH		10	SHARED DISPOSITIVE POWER:
			0
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON:
	9,024,326
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):
	14.4%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):
	IN

Page 13 of 15

     This Amendment No. 23 to Schedule 13D amends and supplements the Schedule 13D filed with the Securities and Exchange Commission (the “Commission”) on June 10, 2002, as amended by Amendment No. 1 to Schedule 13D filed with the Commission on October 20, 2003, Amendment No. 2 to Schedule 13D filed with the Commission on July 12, 2004, Amendment No. 3 to Schedule 13D filed with the Commission on November 16, 2004, Amendment No. 4 to Schedule 13D filed with the Commission on April 19, 2005, Amendment No. 5 to Schedule 13D filed with the Commission on September 7, 2005, Amendment No. 6 to Schedule 13D filed with the Commission on September 29, 2005, Amendment No. 7 to Schedule 13D filed with the Commission on October 11, 2005, Amendment No. 8 to Schedule 13D filed with the Commission on October 14, 2005, Amendment No. 9 to Schedule 13D filed with the Commission on October 21, 2005, Amendment No. 10 to Schedule 13D filed with the Commission on October 27, 2005, Amendment No. 11 to Schedule 13D filed with the Commission on November 17, 2005, Amendment No. 12 to Schedule 13D filed with the Commission on December 8, 2005, Amendment No. 13 to Schedule 13D filed with the Commission on January 30, 2006, Amendment No. 14 to Schedule 13D filed with the Commission on February 14, 2006, Amendment No. 15 to Schedule 13D filed with the Commission on February 15, 2006, Amendment No. 16 to Schedule 13D filed with the Commission on February 23, 2006, Amendment No. 17 to Schedule 13D filed with the Commission on March 16, 2006, Amendment No. 18 to Schedule 13D filed with the Commission on April 13, 2006, Amendment No. 19 to Schedule 13D filed with the Commission on April 25, 2006, Amendment No. 20 to Schedule 13D filed with the Commission on May 24, 2006, Amendment No. 21 to Schedule 13D filed with the Commission on June 2, 2006, and Amendment No. 22 to Schedule 13D filed with the Commission on June 6, 2006 (as amended, the “Schedule 13D”). Capitalized terms used herein which are not defined herein have the meanings given to such terms in the Schedule 13D. Except as otherwise provided herein, all Items of the Schedule 13D remain unchanged.

Item 4. Purpose of the Transaction.

     Item 4 is hereby supplemented as follows:

     On June 13, 2006, counsel for Highland Capital Management, L.P. (“Highland Capital”) filed an ex parte notice with the Federal Communications Commission regarding Highland Capital’s interest in an application for consent to transfer control filed by Motient Corporation (the “Company”). A copy of the notice is attached hereto as Exhibit 99.21 and is incorporated herein by reference.

     As reflected by the foregoing actions, among others, the Reporting Persons are considering various plans or proposals which relate to or could result in the transactions or changes contemplated by Items 4(a) through 4(j) of Schedule 13D. Such plans or proposals could include acquisitions of additional shares in the open market or otherwise and potentially seeking possible changes in the present Board and management of the Company. In the interim and prior to formulating any definitive plan or proposal, the Reporting Persons may communicate with other stockholders regarding their concerns about the actions taken by the Company and its management.

      HIGHLAND CAPITAL STRONGLY ADVISES ALL SECURITY HOLDERS OF THE COMPANY TO READ ITS PROXY STATEMENT WHEN AND IF IT BECOMES AVAILABLE, AS IT WILL CONTAIN IMPORTANT INFORMATION, INCLUDING INFORMATION RELATING TO THE PARTICIPANTS IN ANY SUCH PROXY SOLICITATION. INVESTORS CAN GET THE PROXY STATEMENT, AND ANY OTHER RELEVANT DOCUMENTS, WHEN AND IF AVAILABLE, FOR FREE AT THE COMMISSION’S WEB SITE AT HTTP://WWW.SEC.GOV. IN ADDITION, ANY SUCH PROXY STATEMENT, AND ANY OTHER RELEVANT DOCUMENTS, WHEN AND IF AVAILABLE, WILL BE AVAILABLE FOR FREE FROM THE PARTICIPANTS BY CONTACTING HIGHLAND CAPITAL'S SOLICITOR, MACKENZIE PARTNERS, INC., AT ITS TOLL-FREE NUMBER: (800) 322-2885, OR BY COLLECT CALL AT (212) 929-5550.

      INFORMATION CONCERNING THE IDENTITY OF THE POTENTIAL PARTICIPANTS IN ANY SUCH POTENTIAL PROXY SOLICITATION AND A DESCRIPTION OF THEIR DIRECT OR INDIRECT INTERESTS, BY SECURITY HOLDINGS OR OTHERWISE, IS CONTAINED IN THE SECTION ENTITLED “INFORMATION CONCERNING THE PARTICIPANTS IN THE SOLICITATION” IN THE PRELIMINARY PROXY STATEMENT ON THE SCHEDULE 14A FILED BY HIGHLAND CAPITAL WITH THE COMMISSION ON JUNE 2, 2006 WITH RESPECT TO THE COMPANY. THAT SCHEDULE 14A IS CURRENTLY AVAILABLE FOR FREE AT THE COMMISSION'S WEB SITE. Security holders of the Company can also obtain information concerning the identity of the potential participants in any such potential proxy or consent solicitation and a description of their direct or indirect interests, by security holdings or otherwise, for free by contacting Highland Capital's solicitor, MacKenzie Partners, Inc., at its toll-free number: (800) 322-2885, or by collect call at (212) 929-5550.

Item 7. Material to be Filed as Exhibits.

     Item 7 is hereby amended and supplemented as follows:

Exhibit 99.21 Ex parte notice filed with the Federal Communications Commission with respect to Highland Capital’s interest in an application for consent to transfer control filed by Motient Corporation, dated June 13, 2006.

Page 14 of 15

SIGNATURE

     After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: June 14, 2006
	HIGHLAND CAPITAL MANAGEMENT, L.P.
	By:	Strand Advisors, Inc., its general partner
		By:	/s/ James Dondero
		Name:	James Dondero
		Title:	President
	STRAND ADVISORS, INC.
	By:	/s/ James Dondero
	Name:	James Dondero
	Title:	President
	/s/ James Dondero
	James Dondero
	PROSPECT STREET HIGH INCOME PORTFOLIO, INC.
	By:	/s/ James Dondero
	Name:	James Dondero
	Title:	President
	PROSPECT STREET INCOME SHARES INC.
	By:	/s/ James Dondero
	Name:	James Dondero
	Title:	President
	HIGHLAND LEGACY LIMITED
	By:	Highland Capital Management, L.P., its collateral manager
	By:	Strand Advisors, Inc., its general partner
		By:	/s/ James Dondero
		Name:	James Dondero
		Title:	President

Page 15 of 15

HIGHLAND CRUSADER OFFSHORE PARTNERS, L.P.
By:	Highland Crusader Fund GP, L.P., its general partner
By:	Highland Crusader GP, LLC, its general partner
By:	Highland Capital Management, L.P., its sole member
By:	Strand Advisors, Inc., its general partner
	By:	/s/ James Dondero
	Name:	James Dondero
	Title:	President
PAMCO CAYMAN, LIMITED
By:	Highland Capital Management, L.P., its collateral manager
By:	Strand Advisors, Inc., its general partner
	By:	/s/ James Dondero
	Name:	James Dondero
	Title:	President
HIGHLAND EQUITY FOCUS FUND, L.P.
By:	Highland Equity Focus Fund GP, L.P., its general partner
By:	Highland Equity Focus GP, LLC, its general partner
By:	Highland Capital Management, L.P., its sole member
By:	Strand Advisors, Inc., its general partner
	By:	/s/ James Dondero
	Name:	James Dondero
	Title:	President
HIGHLAND SELECT EQUITY FUND, L.P.
By:	Highland Select Equity Fund GP, L.P., its general partner
	By:	/s/ Michael S. Minces
	Name:	Michael S. Minces
	Title:	Vice President
HIGHLAND CAPITAL MANAGEMENT SERVICES, INC.
By:	/s/ James Dondero
Name:	James Dondero
Title:	President

EX-99.21

Exhibit 99.21

	Reed Smith llp
	1301 K Street, N.W.
	Suite 1100 — East Tower
James P. Schulz	Washington, D.C. 20005-3373
Direct Phone: 202.414.9234	202.414.9200
Email: jschulz@reedsmith.com	Fax 202.414.9299

June 13, 2006

BY ELECTRONIC DELIVERY

Ms. Marlene H. Dortch
Secretary
Federal Communications Commission
445 12th Street, S.W.
Washington, DC 20554

Re:	Ex Parte Notice
	WC Dkt. No. 06-106

Dear Ms. Dortch:

     On June 13, 2006, on behalf of Highland Capital Management, LP (“Highland”), the undersigned met with Emily Willeford, Advisor for International Issues and Deputy Chief of Staff, Office of Chairman Martin. The purpose of the meeting was to discuss Highland’s interest in the application for consent to the transfer of control of Mobile Satellite Ventures Subsidiary, LLC and MSV International, LLC filed by Motient Corporation and SkyTerra Communications, Inc.

Respectfully Submitted,

James P. Schulz

Judith L. Harris

JPS:em

NEW YORK w LONDON w LOS ANGELES w PARIS w SAN FRANCISCO w WASHINGTON, D.C. w PHILADELPHIA w PITTSBURGH w OAKLAND

MUNICH w PRINCETON w FALLS CHURCH w WILMINGTON w NEWARK w MIDLANDS, U.K. w CENTURY CITY w RICHMOND w LEESBURG

r e e d s m i t h . c o m