Telemetry
Automated data transmitted from a spacecraft to a ground station, reporting on the health, status, and performance of onboard systems.
Full Definition
Spacecraft telemetry encompasses housekeeping data (temperatures, voltages, currents, switch states) and engineering data that ground operators use to assess satellite health and diagnose anomalies. Telemetry is received at TT&C ground stations and processed by ground support equipment to generate trend plots, alarm notifications, and operational reports. Editors must note that 'telemetry' is an uncountable noun in standard industry usage ('the telemetry showed…', not 'a telemetry showed…'). It should not be confused with 'telecommand' or 'commanding,' which refer to the uplink direction. The shortened form 'TM' is common in spacecraft engineering documents.
Usage
Usage note: Uncountable noun — avoid 'a telemetry' or 'telemetries.' The abbreviation TM is acceptable after first use. Do not confuse with telecommand (TC), the uplink counterpart.
In Context
- "Telemetry indicated a 2°C rise in the battery temperature following the shadow exit maneuver." — Spacecraft health report
- "The ground system processed 1,440 telemetry frames per orbit, archiving each to the mission database." — Ground-segment operations description