PASADENA, Calif. -- NASA mission controllers have not heard from the Mars Exploration Rover Spirit since March 22, and the rover is facing its toughest challenge yet - trying to survive the harsh Martian winter.
The rover team anticipated Spirit would go into a low-power "hibernation" mode since the rover was not able to get to a favorable slope for its fourth Martian winter, which runs from May through November. The low angle of sunlight during these months limits the power generated from t [...]