Testing

Verification methods, facilities, and simulants used to qualify robotic hardware for environments that cannot be reproduced in full on Earth. Each page covers what the method reproduces, what it does not, the fidelity limits that have caused flight surprises, and the facilities where the work is done.

Ground qualification is checked against the flight it was predicting only rarely, and the matched cases are specific rather than general. Curiosity’s accumulated flight thermal cycles have been rainflow counted against the accelerated cycling test run on the same board design [1]. The MSL generator’s output was measured against its pre-flight prediction at three points before launch and once on the surface [2]. Mast pointing accuracy achieved on Mars was carried into the Mars 2020 requirement as an operational figure with outliers rather than as the ground expectation it replaced [3].

Facility capability parameters have almost no counterpart of that kind. Chamber base pressure, bed density and preparation state, slope, illumination and gravity offload fidelity are published as what a rig delivers to an article standing on or inside it, and none of them is re-measured on the hardware once it is working in the place the rig stood in for. A facility envelope is therefore a capability statement and not an error bar against flight, and most stated fidelity limits are arguments from physics rather than measured discrepancies.

Two thermal vacuum cases are the exception, and both are on flight vehicles. The Mars 2020 system thermal vacuum test concluded that a cruise thruster catalyst bed heater could stay on continuously from launch, which flight contradicted, because the chamber simulated no off-Sun angle flux [4]. Perseverance’s correlated thermal model inherited the 4 percent voltage loss of the ground support equipment cabling in place of the 9 percent of the flight flex cables, which produced preheat ramp rate errors above 5 C in flight until the cable loss was corrected [5]. Both are covered on thermal vacuum testing.