Mars Rovers Are Hanging On

NASA Mars Exploration Rover Spirit Update: Dust from Martian Sky Accumulates on Solar Panels

“Dust from Martian Sky Accumulates on Solar Panels – sol 1284-1287, August 20, 2007: Even though the Martian sky above Gusev Crater continued to clear, solar power levels on NASA’s Spirit rover remained fairly constant as dust settling from the atmosphere accumulated on top of the solar panels. Activities remained restricted. Measurements of atmospheric opacity, known as Tau, dropped from 3.6 on Martian day, or sol, 1283 (Aug. 12, 2007) to 3.3 on sol 1286 (Aug. 16, 2007), generating power levels of 301 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour).”