What is the power source of the Pathfinder?
The Mars Pathfinder is powered during cruise by a non-deployable solar array that uses Gallium-Arsenide solar cells. This provides all of the power during nominal cruise conditions. During Launch and the Entry, Descent and Landing on the surface of Mars the spacecraft will be powered by a rechargeable battery. The rechargeable battery has silver cathode, zinc electrode, and potassium hydroxide electrolyte. Once, the lander has landed and the petals have been opened the lander is powered by another solar array that uses the same type of gallium-arsenide solar cells. During the night time and for peak power loads the spacecraft is powered using the same rechargeable battery used during cruise. The rover similarly is powered by a fixed array on gallium-arsenide solar cells. Again peak power loads and night-time loads are supported by using a battery. The battery for the rover isn’t rechargeable and thus uses a different chemistry. –Richard Ewell, Mars Pathfinder Power Subsystem Engineer
