Chassis Short Mitigation and Characterization Technique for the Multi-Mission Radioisotope Thermoelectric Generator

The radioisotope thermoelectric generator (RTG) is a flight-proven, capable source of power that reliably converts heat into electricity. NASA and the Department of Energy (DoE) have developed a new generation of such power systems that could be used for a variety of space missions. The newest RTG, called a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), has been designed to operate on Mars and in the vacuum of space. However, shorts between the internal electrical power circuit and chassis frame of the MMRTG have been observed in the engineering unit, qualification unit, and flight unit. The internal shorts seemed to appear and sometimes clear spontaneously. A root cause has not been determined for these internal shorts, and their resistance, power rating, and energy rating are largely unknown. A mitigation and measurement technique is needed.