What is telemetry in spacecraft operations?

What is telemetry in spacecraft operations?

• A. Data transmitted from a spacecraft to Earth detailing status, health, and environment.
• B. A command sent from ground to spacecraft to perform a maneuver.
• C. A cryptographic key exchange between ground and satellite.
• D. A video feed of onboard instruments.

Answer: (A)

Telemetry is the data stream sent from a spacecraft to Earth that reports the vehicle’s status, health of systems, and its environment. It includes measurements such as temperatures, voltages, currents, subsystem states, attitude, power, and sensor readings, typically organized into packets with timestamps so operators can monitor performance and detect anomalies. This feedback loop lets mission control verify everything is operating within limits and take corrective actions if needed, ensuring safe and successful operations between ground commands.

Other data like a telecommand (ground-to-space instruction) or a cryptographic key exchange are about control or security, not the ongoing status data. A video feed can be part of the mission’s data, but telemetry specifically refers to the health, status, and environmental measurements that describe how the spacecraft is functioning.