Tracking, Telemetry, and Command Subsystem (TT&C)

The Tracking, Telemetry, and Command (TT&C) Subsystem is the spacecraft subsystem responsible for monitoring, controlling, and maintaining a satellite throughout its mission. It comprises three functional elements.

Tracking determines the satellite’s position and motion by measuring parameters such as angle, range, and radial velocity, enabling orbit determination and prediction. Telemetry collects, encodes, and transmits health and status data from the spacecraft’s subsystems, allowing operators to monitor performance and detect faults. The command function receives, validates, and executes control commands sent from the ground to modify spacecraft configuration, operating modes, attitude, orbit, and velocity.

Together, the TT&C functions provide the essential interface between the spacecraft and the ground control segment, supporting safe operation, anomaly resolution, and end-of-life disposal.