Advanced Skutterudite-Based Unicouples for a Proposed Enhanced Multi-Mission Radioisotope Thermoelectric Generator: An Update

Tuesday, 3 October 2017: 10:50
Chesapeake F (Gaylord National Resort and Convention Center)
I. S. Chi, K. Smith, C. K. Huang, S. Firdosy, K. Yu, B. Phan, S. Sujittosakul, B. C. Y. Li, J. A. Paik, P. Gogna, S. Chanakian, J. Ni, M. Aranda, S. Pinkowski, T. Hendricks, J. P. Fleurial, and T. Caillat (Jet Propulsion Laboratory)
Radioisotope Thermoelectric Generators (RTG’s) have been used on several NASA missions when they enable or significantly enhance the ability of a mission to meet its objectives. The current state-of-the-art RTG power source, Curiosity rover’s Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), has operated for more than one Martian year (687 earth days) on the red planet. In order to increase the power and conversion efficiency of future MMRTG systems and extend the lifetime of future rover missions, an effort was started in 2013 to mature advanced thermoelectric technology for use in a proposed Enhanced Multi-Mission Radioisotope Thermoelectric Generator (eMMRTG). The conceptual design approach of the eMMRTG is to replace the heritage MMRTG couples in the thermoelectric module assembly with more advanced skutterudite (SKD)-based couples without any significant design changes to the generator. The new SKD thermoelectric materials not only can provide higher thermoelectric performance, but also can operate at higher maximum operating temperature than MMRTG thermoelectric materials. As a result, the proposed eMMRTG would preserve all the MMRTG’s multi-mission capability while offering an expected enhancement in power, relative to MMRTG, of about 25 % at beginning-of-life and potentially lower power degradation rates leading to a ≥ 50% increase in power at end-of-design life (17 years) with an 80W power output goal at 17 years. Here, we will report on the progress for demonstrating manufacturability and validating performance of these advanced SKD unicouples jointly developed and tested by Jet Propulsion Laboratory (JPL) and Teledyne Energy Systems, Inc. (TESI).