Commission a connected spacecraft

Commissioning is the process of checking and preparing systems for their intended operations after launch. A spacecraft may report healthy battery voltage while its mission payload cannot deliver useful data. Platform housekeeping, payload measurements and ground-product delivery involve overlapping but different paths. A successful result in one path does not automatically qualify the others.

SANSA’s 2023/24 annual report states that issues with an onboard communication bus prevented completion of MDASat payload commissioning. It also reports delays in investigation after loss of personnel. That dated account qualifies the earlier launch publicity. It does not provide a complete failure analysis or establish that every subsystem stopped working.

Imagine a bench test in which a payload produces a known packet, the onboard computer receives it, the downlink transmits it and ground software decodes it. Give the test packet an identifier and inspect it at each boundary. If it leaves the payload but never reaches the computer, investigate the intervening interface and both endpoints. Possible causes include timing, configuration, software and hardware; the observation alone does not select one.

An onboard communication bus carries data between components. It is different from the radio link between spacecraft and ground. A fault in the internal path can prevent useful payload delivery even if a separate housekeeping beacon remains audible. In the invented test, bypassing one interface with a simulator may narrow the problem, but the complete path must later be tested again with the real components.

Inspect the data at each boundary

CPUT’s January 2022 update described one spacecraft starting in fail-safe mode and recovering after a requested reset. That early event should not be silently equated with the later bus issue. Similar words such as “communication problem” can describe different incidents, components and times. A recovery action needs a recorded symptom, configuration and result.

Suppose new software restores packet transfer. Repeat the failing case, then run representative valid cases and error cases. Confirm that timestamps, packet identifiers and content survive delivery. Check restart behavior as well as steady operation. A test that merely makes an error message disappear could still discard measurements. Keep a recoverable known-good configuration when evaluating an update, subject to the actual spacecraft’s capabilities.