Robert Briskman, SIRIUS XM Radio’s Co-Fouder, Awarded The 2008 IEEE AESS Pioneer

Award New York August 21, 2008 SIRIUS XM Radio (NASDAQ: SIRI) announced today that Robert Briskman, SIRIUS XM Radio’s co-founder, has been chosen as the 2008 recipient of the IEEE AESS Pioneer Award. The award ceremony will be held in Bologna, Italy during the Advanced Satellite Mobile Systems Conference (ASMS 2008). The Pioneer Award has been given annually since 1949 to an individual or team for contributions significant to introducing electronic or aerospace systems of interest to society that are still in existence today. This year, Briskman is honored for the development of commercial communications and broadcast satellites over the past 40 years. IEEE is the world’s leading professional association for the advancement of technology. Through its global membership, IEEE is a leading authority on areas ranging from aerospace systems, computers and telecommunications to biomedical engineering, electric power and consumer electronics among others. Members rely on IEEE as a source of technical and professional information, resources and services and to foster an interest in the engineering profession. Robert D. Briskman was Chief Technical Officer and Executive Vice President, Engineering of SIRIUS XM Radio since its founding in 1991 as Satellite CD Radio Inc. and is currently its Technical Executive. As the technical innovator of mobile satellite radio services, he was responsible for the development, implementation and operation of SIRIUS broadcast distribution system. His technology development responsibility included design of low cost satellite receiving terminals for automobiles and of broadcast sound programming, earth station, terrestrial repeaters and satellite control facilities. During 2000, Briskman supervised the launch of three SIRIUS satellites into a unique operational orbital constellation which he designed. For over three decades, Briskman has directed the implementation of satellite telecommunications systems at COMSAT and NASA. He holds a BSE degree from Princeton University and an MSEE degree from the University of Maryland. Briskman is a Fellow of IEEE and AIAA. He has published over 50 technical papers, holds a number of patents, and has been inducted into the Space Foundation and SSPI Halls of Fame. About SIRIUS XM Radio SIRIUS XM Radio is America’s satellite radio company delivering The Best Radio on Radio to more than 18 million subscribers, including 100% commercial free music, and premier sports, news, talk, entertainment, traffic and weather. SIRIUS XM Radio has exclusive content relationships with an array of personalities and artists, including Howard Stern, Oprah, Martha Stewart, Jimmy Buffett, Elvis, Jamie Foxx, Barbara Walters, Frank Sinatra, Opie & Anthony, The Grateful Dead, Willie Nelson, Bob Dylan, Dale Earnhardt Jr., Tom Petty, and Bob Edwards. SIRIUS XM Radio is the leader in sports programming as the Official Satellite Radio Partner of the NFL, Major League Baseball, NASCAR, NHL, and PGA Tour, and broadcasts major college sports. SIRIUS XM Radio has exclusive arrangements with every major automaker. SIRIUS XM Radio products are available at shop.sirius.com and shop.xmradio.com, and at retail locations nationwide, including Best Buy, Circuit City, RadioShack, Target, Sam’s Club, and Wal-Mart. SIRIUS XM Radio also offers SIRIUS Backseat TV, the first ever live in-vehicle rear seat entertainment featuring Nickelodeon, Disney Channel and Cartoon Network; XM NavTraffic service for GPS navigation systems delivers real-time traffic information, including accidents and road construction, for more than 80 North American markets. This communication contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements include, but are not limited to, statements about the benefits of the business combination transaction involving Sirius Satellite Radio Inc. and XM Satellite Radio Holdings Inc., including potential synergies and cost savings and the timing thereof, future financial and operating results, the combined company’s plans, objectives, expectations and intentions with respect to future operations, products and services; and other statements identified by words such as anticipate, believe, plan, estimate, expect, intend, will, should, may, or words of similar meaning. Such forward-looking statements are based upon the current beliefs and expectations of SIRIUS and XM’s management and are inherently subject to significant business, economic and competitive uncertainties and contingencies, many of which are difficult to predict and generally beyond the control of SIRIUS and XM. Actual results may differ materially from the results anticipated in these forward-looking statements. The following factors, among others, could cause actual results to differ materially from the anticipated results or other expectations expressed in the forward-looking statement: general business and economic conditions; the performance of financial markets and interest rates; the ability to obtain governmental approvals of the transaction on a timely basis; the failure to realize synergies and cost-savings from the transaction or delay in realization thereof; the businesses of SIRIUS and XM may not be combined successfully, or such combination may take longer, be more difficult, time-consuming or costly to accomplish than expected; and operating costs and business disruption following the merger, including adverse effects on employee retention and on our business relationships with third parties, including manufacturers of radios, retailers, automakers and programming providers. Additional factors that could cause SIRIUS and XM’s results to differ materially from those described in the forward-looking statements can be found in SIRIUS and XM’s Annual Reports on Form 10-K for the year ended December 31, 2007, which are filed with the Securities and Exchange Commission (the “SEC”) and available at the SEC’s Internet site ( http://www.sec.gov ). The information set forth herein speaks only as of the date hereof, and SIRIUS and XM disclaim any intention or obligation to update any forward looking statements as a result of developments occurring after the date of this communication. G-SIRI?