Application of PbTe/TAGS CPA thermoelectric module technology in RTGs for Mars surface missions

Abstract

This paper presents the status of PbTe/TAGS close‐pack‐array (CPA) thermoelectric module technology developed by Teledyne Energy Systems for use in terrestrial radioisotope thermoelectric generators (RTGs), and discusses application of this technology to RTGs for Mars surface missions. Low‐power RTGs with power levels ranging from 3 to 20 We have been identified as candidate power sources for various scientific packages to be landed on the Martian surface. This power range is consistent with the use of PbTe/TAGS CPA technology. Modifications required for the current CPA technology to increase mechanical shock loading capability and to permit operation at the higher temperatures required for efficient operation in the Martian planetary environment are identified. A conceptual 15‐We space RTG design incorporating CPA technology is presented. CPA technology permits a significant improvement in the specific power of PbTe/TAGS RTG units, even at these relatively low power levels. Specific power is in the 3.7 We/kg (1.7 We/lb) range for RTGs employing CPA technology compared with approximately 2.2 We/kg (1 We/lb) for the RTGs employed in the NASA Pioneer Jupiter Fly‐by and Viking Mars Lander missions in the 1970s.