The German TV-Sat broadcasting satellite system

The design concept, service and communication modules, and characteristics of the TV-Sat system are described. Also discussed are the solar array, propulsion and antenna modules as well as the high-power amplifier. A dual control system is used for the coarse pointing of the satellite´s body (by infrared earth sensors) and the fine pointing of antenna reflectors. Fine pointing is done by an RF-sensor and 2 pointing mechanisms (APM). In the case of TV-Sat, 90% of the power is required by the payload; only the subsystems AOCS (attitude and orbit control system), TTC (telemetry, tracking and command system), and UPS are not dependent on the payload. The power required by these subsystems is supplied by the solar array structure with an output of 68 W/m/sup 2/ and 19.4 W/kg. The methods by which a high mean temperature is achieved and heat dissipation problems are examined. In-orbit tests with TV-Sat 1 are presented.<>