Energy conversion technologies for advanced radioisotope and nuclear reactor power systems for future planetary exploration

This paper examined candidate energy conversion technologies for advanced radioisotope and space nuclear reactor power systems, including three static, SiGe, segmented and cascaded thermoelectric, and alkali-metal thermal-to-electric conversion, and two dynamic, free piston Stirling and closed Brayton engines; each is at a different technology readiness level (TRL). The eventual selection of the appropriate technology for a class of missions would be based not only on the TRL, but also on considerations of safety, systems´ specific power, mission lifetime, specific radiator area (m²/kWe), and the overall system´s mass and size. Other important considerations are modularity, reliability, scalability, load following, power management and distribution requirements, radiation hardness integration into the spacecraft, and absence of single point failures.