The Little Rover that could is the undisputed extraterrestrial ground distance champion.

The Little Rover that could is the undisputed extraterrestrial ground distance champion.

10 years into a 90-day mission, little robot has traveled 25 miles (40.25 km) on Mars. Soon it will have completed the second slowest marathon ever.

http://arstechnica.com/science/2014/07/long-lived-opportunity-rover-breaks-extraterrestrial-mileage-record/