A satellite-based direct-broadcast radio service in which digitally encoded audio entertainment material is broadcast to Earth-based receivers, either directly from an orbiting satellite, or--in cases in which the receiver is in a shielded location--from the satellite to the receiver via a repeater station. 2. A radiocommunication service in which audio programming is digitally transmitted by one or more space stations directly to fixed, mobile, and/or portable stations, and which may involve complementary repeating terrestrial transmitters, telemetry, tracking and control facilities. 3. A radiocommunication service in which compact-disc quality programming is digitally transmitted by one or more space stations.