"Based on wheel rotations Lunokhod 2 was thought to have covered 37 km but Russian scientists have revised that to an estimated distance of about 42 km based on orbital images of the lunar surface.
As of June 6, 2013, its journey remained the longest any robotic rover, or any vehicle, that had ever driven on another celestial body; the crewed Apollo 17 Lunar Roving Vehicle travelled 35.75 km, and the still extant robotic Opportunity Rover had travelled 36.61 km on Mars." http://en.wikipedia.org/wiki/Lunokhod_2
CRUD = Contamination Resulting in Undesirable Deposits.
CRAPP = Contamination Resulting in Additional Partial Pressure.