Command and Telemetry Systems

The Telstar satellite includes circuits designed to perform two basic experiments: (i) a communications experiment using a wideband, active repeater and (u) a radiation experiment designed to provide information on the environment in outer space and the effects of this environment on devices used in communication circuits. The command and telemetry portions of the Telstar system provide a very necessary support function for these experiments. This paper discusses the over-all command and telemetry systems; it considers first the need and general objectives and then the systems aspects of the design. Finally it gives a detailed discussion of the implementation of each system. The need for a command system for the Telstar project arises primarily because of power considerations associated with the satellite repeater: the communications circuits consume more power than the solar plant is capable of supplying. 1 To be able to operate under full load, batteries are provided which supply the additional power needed during operation of the communications circuits. During those intervals when the communications circuits are not on, the batteries are recharged by the solar plant. Hence a command system is necessary to turn the high-power communications circuits on and off. Having provided a 1027