Performance of BST systems silver zinc lander battery during the mars pathfinder mission

摘要

The Mars Pathfinder mission required a 27 volt/50 AH silver zinc battery capable of at least 40 deep cycles and a 14 month wet life (5-6 months stand (on Earth), 7 months cruise (to Mars), 30 day Mars surface operations). In addition, in order toaccommodate launch vehicle geometry, the activated battery was required to be capable of withstanding up to 4 months in the inverted (cell terminals down) configuration with no leakage or subsequent loss in performance.In order to meet these stringent requirements, innovations were incorporated into the battery design, including the use of ultrasonic sealing techniques, the use of composite separator systems, and features designed to meet the challenge of electrolytemanagement.Data is presented on the mission performance of BST Systems Pathfinder battery during launch (in December 1996), the 7 month cruise, planetary landing (on July 4, 1997) as well as during Mars surface operations. Battery design features are reviewed andcompared to results obtained from the actual Pathfinder mission. Data presented includes capacity retention following the 7 month cruise to Mars, battery recharge performance on the Martian surface, as well as the discharge characteristics of a fullyoperational battery in environments of low temperature and low gravity.The battery met all of the JPL/NASA requirements and supported Martian surface operations for 85 days, nearly three times the JPL requirement of 30 days.