From Symphonie to Phebus - Steps in innovating for communications satellites

Following the launches of the Franco-German Symphonie A and B satellites (in 1974 and 1975) and their successful performance of several communications experiments, consideration was given to an advanced communications satellite to be orbited by the launch vehicle Ariane, which will have a synchronous orbit capability of about 970 kg. This advanced generation of communications satellites, termed the Phebus series, stresses modular systems to provide flexibility in developing point-to-point communications, TV broadcast, and earth observation satellite systems. Structure and thermal control, attitude and orbit control, the apogee boost motor, telemetry and power supplies of the Phebus series are described, and millimeter wave and electrical propulsion experiments planned within the framework of the series are mentioned.