Primary Batteries for Emerging Deep Space Exploration Missions

Abstract

Primary batteries have played a critical role in past deep space planetary exploration missions, providing power to spacecraft such as the Galileo and Huygens Probes [1,2]. Most of these missions were of relatively short duration (Huygens lasted 2.5 hours), and relied on primary battery power alone to execute mission profiles. Future missions planned by the National Aeronautics and Space Administration (NASA) to the outer planets (Jupiter, Saturn) and their moons (Europa, Enceladus, Titan) will require more advanced primary batteries to provide bus power for days or even weeks. These batteries may be stored for several years during an initial cruise period, followed by operation in temperature extremes coupled with exposure to high radiation doses. The requirement for primary batteries with very high specific energy, low self-discharge/long calendar life performance, wide temperature operation and radiation tolerance has prompted the evaluation by NASA of commercially available options, as well as the development of new components and cell designs. This includes higher specific energy battery chemistries such as Li/CFx and Li/CFx-MnO2, which provide for a higher capacity per unit mass at moderate rates, relative to Li/SO2 and Li/SOCl2 chemistries used in previous missions. Current efforts to evaluate the effects of radiation and storage on these primary battery chemistries will be discussed in relation to future NASA needs. ACKNOWLEDGEMENT The work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration (NASA). L.M. Hofland, E.J. Stofel, R.K. Taenaka, Aerospace and Electronic Systems Magazine IEEE, 11, 14 (1996). B.P. Dagarin, R.K. Taenaka, E.J. Stofel, Proc. of 31st Energy Conversion Engineering Conference 1996, 1, 427 (1996).