Spacecraft Technology- Structure:
A satellite communications system can be broadly divided into two segments—a ground segment and a space segment.
The space segment will obviously include the satellites, but it also includes the ground facilities needed to keep the satellites operational, these being referred to as the tracking, telemetry, and command (TT&C) facilities. In many networks it is common practice to employ a ground station solely for the purpose of TT&C.
The equipment carried aboard the satellite also can be classified according to function. The payload refers to the equipment used to pro- vide the service for which the satellite has been launched.
In a communications satellite, the equipment which provides the connecting link between the satellite’s transmit and receive antennas is referred to as the transponder. The transponder forms one of the main sections of the payload, the other being the antenna subsystems.In this chapter the main characteristics of certain bus systems and payloads are described.