Application of commercial electronics in the motors and actuator systems for Mars surface missions

Commercial-off-the-shelf electronic components (COTS) offer a very low cost and attractive solution for construction of electronic systems for Mars missions, including the actuator electronic systems for the Mars Rovers. One issue with using COTS lies in the difference between their specified operating temperature range (-55°C to125°C for military components) and the temperatures observed at the surface of Mars (-120°C to 20°C). To compensate for the difference between these temperatures, most of the electronics are placed in a central warm-electronics-box or WEB. In some cases, such as the distributed control system for the actuators, the electronic assemblies that are to be placed on or near the motors are outside of the central WEB. The experimental search consists of two steps. First, a short functional/non-functional test at -120°C is used to identify and narrow down the number of candidate COTS that can work at very cold temperatures. More extensive characterization of the parts that passes the short test is performed to determine the operating margins and estimate the thermal cycle life capability for the COTS parts. Finally, the operating margins of the COTS parts are published as a set of specifications.