The multimission radioisotope thermoelectric generator for NASA’s Mars 2020 Perseverance rover is tested at NASA’s Kennedy Space Center in 2020. The choice of an MMRTG as the rover’s power system gave mission planners significantly more flexibility in selecting the rover’s landing site and in planning its surface operations. (Photo: NASA)

Under the Radioisotope Power Systems Program, NASA and the Department of Energy have been advancing a novel radioisotope power system (RPS) based on dynamic energy conversion. This approach will manifest a dynamic RPS (DRPS) option with a conversion efficiency at least three times greater than a thermoelectric-based RPS. Significant progress has recently been made toward this end. A one-year system design phase has been completed by NASA industry partner Aerojet Rocketdyne, which resulted in a DRPS with power of 300 watts-electric (We) with convertor-level redundancy. In-house technology development at the NASA Glenn Research Center (GRC) has demonstrated the conversion devices in relevant environments and has shown all requirements can be met. Progress has also been made on the control electronics necessary for dynamic energy conversion. Flight-like controllers were recently upgraded and achieved an 11-percentage-point increase in efficiency. Control architectures have been developed to handle the multiconvertor arrangements in the latest DRPS design. A system-level DRPS testbed is currently being assembled that will experimentally demonstrate the DRPS concept being pursued.