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Motor Qualification for Long-Duration Mars Missions

Qualification of motors for deep space under extreme thermal environments to be encountered during the Mars Science Laboratory (MSL) mission is required to verify the reliability and validate mission assurance requirements. The motor assembly must survive all ground operations, plus the nominal 670 Martian-day (or sol) mission that includes summer and winter seasons of the Mars environment. The motor assembly was tested and characterized under extreme temperature conditions with reference to hardware requirements. The motor assembly has been proved to be remarkably robust and displayed no sign of degradation due to the 3× (three times per JPL design principles) thermal environmental exposure to the punishing Mars surface operations cycles. The motor characteristics obtained before, during, and post-test comparisons for the surface operations cycles are within measurement error of one another.

The motors withstood/survived 2,010 extreme temperature cycles with a ΔT of 190 °C deep temperature cycles, representing three times the expected thermal cycling exposure during the MSL surface operations. The qualification test hardware elements (A200 motor assembly, encoders, and resolver) have not shown any signs of degradation due to the PQV (Package Qualification and Verification) testing. The test hardware has demonstrated sufficient life to survive the deep thermal cycles associated with MSL mission surface operations for three lives.

This work was done by Rajeshuni Ramesham, Michael R. Johnson, Darren T. Cooper, Warren S. Lau, Kobie T. Boykins, Jonathan D. Perret, and Richard A. Rainen of Caltech; and Andrea Greb of Orbital for NASA’s Jet Propulsion Laboratory. NPO-48760

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Motor Qualification for Long-Duration Mars Missions (reference NPO-48760) is currently available for download from the TSP library.

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