Concept for a Cascaded Multi-Mission Radioisotope Thermoelectric Generator

A multi-mission radioisotope thermoelectric generator (MMRTG) powers Curiosity, the National Aeronautics and Space Administration (NASA) Mars Science Laboratory rover on Mars. Consideration is being given to the feasibility of integrating a second thermoelectric circuit of bismuth telluride (Bi2Te3) into the MMRTG design in order to improve the beginning-of-life (BOL) and end-of-design life (EODL) performance. The maturity of Bi2Te3 and the design flexibility of a cascaded approach enable a low-risk system upgrade that is predicted to enhance the MMRTG's performance. Initial studies indicate that the integration of a second stage Bi2Te3 thermoelectric circuit could potentially provide an approximate 20% increase in power output at BOL and EODL (with EODL defined as 17 years from fueling). This paper presents an overview of the results of the study.