Development of a Lithium/Thionyl Chloride Battery for the Mars Microprobe Program

摘要

The Mars Microprobes (2) are a secondary payload on the 1998 Mars Surveyor Lander Mission. After an eleven month journey to Mars, the two probes will be released and use a self-orienting, non-ablative aeroshell for their single-stage passive entry, decent and landing on Mars. The Microprobes will penetrate the aeroshell on impact with the surface at a velocity of approximately 200 m/sec and separate into two sections; a surface (aft-body) module which contains the power source and telecommunication subsystem and a subsurface (fore-body) module which contains most of the scientific instrumentation. The fore-body is expected to penetrate into the Martian surface between 0.3 and 2 m while the aft-body remains on the surface. The two components are connected through a flex cable umbilical.The Microprobe power source is a four-cell lithium / thionyl chloride battery with a second redundant battery in parallel. The eight 2Ah cells are arranged in a single-layer configuration in the aft-body. The lithium primary cells (and battery configuration) have been designed to survive the maximum landing impact that may reach 80,000 G and be operational on the Martian surface to -80°C. Primary lithium batteries were selected for the Microprobes based on high specific energy and promising low temperature performance.