Mars Pathfinder Lander Battery and Solar Array Performance

Mars Pathfinder Lander was powered by Ga-As solar cells and a silver-zinc Battery. Solar cells were mounted on the three lander petals. The primary source of power was provided by the solar array during daylight operation. The solar array produced a maximum power of 180 watts on the Martian surface. A 27 V , 40 Ah, AgZn battery provided the power needed during the night t.rie and for peak power loads. The power system employed direct energy transfer to minimize energy losses. The battery and the loads were tied directly to the bus and the excess electrical energy from the solar array, after meeting the load requirements, was made available for battery charging. The lander solar array and battery performed satisfactorily and met the mission needs during Pre-Launch, Launch, Cruise, Entry, Descent, Landing, and primary mission (Sol 1 through Sol 30). In addition, they supported an extended mission from Sol 31 through Sol 84. This paper gives an overview of the power subsystem and describes the design and performance of the lander solar array and battery.