What distinguishes housekeeping data from science data in telemetry?

• A. Housekeeping data are telemetry metadata about system health (temperatures, voltages, status flags).
• B. Housekeeping data are telemetry health metadata; science data are measurements from sensors.
• C. Science data are sampling rates; housekeeping data are timestamps.
• D. Housekeeping data are video data; science data are sensor statuses.

Answer: (B)

Housekeeping data are the telemetry that describe the health and status of the spacecraft and its subsystems—temperatures, voltages, current, status flags, and other engineering indicators. They’re there to monitor how the system is operating and to support safe, reliable control. Science data, by contrast, are the actual measurements produced by the science instruments—the physical quantities the mission is designed to study, such as sensor counts, spectra, particle fluxes, or other payload readings.

So the distinction isn’t about format or timestamps; it’s about what the data represent. HK tells you how the system is behaving; science data tell you what the environment or phenomenon is doing. That’s why the best answer characterizes housekeeping data as health telemetry and science data as sensor measurements.