This paper presents the system architecture and expected link availability for the Sirius satellite radio system for both the contiguous United States (CONUS) and Canada service regions. Sirius delivers over 100 channels of talk and music to subscribers in CONUS. The service is available to different markets, such as vehicles, homes, portables, marine, and aviation, and is offered on a subscription basis. Descriptions and performance of the Sirius system are detailed herein. Copyright (C) 2008 John Wiley & Sons, Ltd.