CLARION JOINS XM SATELLITE RADIO'S ELITE TEAM OF RADIO MANUFACTURERS

National, December 13, 1999 -- XM Satellite Radio Inc. (NASDAQ:XMSR) today announced that Clarion Co. Ltd., a world leader in the car audio and mobile electronics industry, will develop, manufacture and market radios capable of receiving XM's new radio broadcast service. The announcement was made by Jim Minarik, President and CEO of Clarion Corporation of America, and Hugh Panero, President and CEO of XM Satellite Radio.

XM Satellite Radio is developing a new band of radio, targeted to launch in early 2001. XM will create up to 100 channels of digital-quality music, news, sports, talk and children's programming, which will be uplinked to XM's powerful satellites and transmitted directly to vehicle, home and portable radios from coast to coast for a monthly subscription fee of $9.95. XM is backed by a group of industry-leading strategic investors, including General Motors, Clear Channel Communications and DIRECTV, the leading car, radio and satellite companies in the US.

"We are very pleased that Clarion, a leading developer of automobile multimedia entertainment, will offer AM/FM/XM radios to their impressive list of automotive manufacturing partners," said Mr. Panero. "This deal underscores the momentum XM Satellite Radio is building as more and more consumer electronics giants join us to build the next generation of radio."

"Clarion is pleased to partner with XM Satellite Radio," said Mr. Minarik. "XM Satellite Radio complements Clarion's continuing commitment to provide our customers cutting-edge and revolutionary, yet affordable, products for the new millennium."

Clarion joins XM's elite group of radio manufacturing partners. Alpine, Delphi-Delco, Mitsubishi Electronics Automotive America, Motorola, Pioneer and Sharp have already announced that they will manufacture and market XM-capable radios.

About Clarion

Clarion Co. Ltd. of Japan has been an international leader in car audio and electronics since 1940. The company conducts research, development, engineering, design and manufacturing, marketing and sales of in vehicle systems and products of entertainment, communication, security, computing and navigation. Clarion has more than 15,000 employees worldwide and 24 factories in nine countries, and marketing and sales affiliates in North and South America; where Clarion Corporation of America, based in Gadena is the regional headquarter, Europe, Asia and Australia. For more information, Clarion is located on the Web at www.clarionmultimedia.com, and www.clarion.co.jp.

About XM

In October 1999, XM Satellite Radio (NASDAQ:XMSR) completed a successful public offering on NASDAQ. American Mobile Satellite Corporation (NASDAQ:SKYC) holds controlling interest in the company. XM's other investors include industry leaders Clear Channel Communications Inc.; DIRECTV, Inc., a unit of Hughes Electronics Corporation; the General Motors Corporation; and a private investment group comprised of Columbia Capital, Telcom Ventures L.L.C., and Madison Dearborn Partners, which together invested $250 million in the company in July 1999. XM Satellite Radio obtained one of only two satellite digital audio radio service (SDARS) licenses from the Federal Communications Commission in October 1997. First there was AM, then FM and soon ... XM Satellite Radio. For more information, please visit the XM website: www.xmradio.com.

Factors that could cause actual results to differ materially from those in the forward-looking statements in this press release include uncertainties associated with the launch of our satellites, our dependence on third party equipment vendors, our continuing need for additional financing, as well as other risks described in our registration statement on Form S-1 (File No. 333-83619) with the Securities and Exchange Commission. Copies of the filing are available upon request from our Investor Relations Department.