What sort of solar panels are being used for the rovers?
The rovers use gallium arsenide solar cells. At the beginning of the mission, the solar arrays will generate about 140 watts of power for up to 4 hours per day, but by the end, dust on the panels, weaker sunlight, seasonal change, and battery wear will reduce that amount to about 50 watts, not enough power for the rover to drive or keep warm at night.
