Since it landed in 2004, Opportunity has logged more than 25 miles along Mars' rusty red roads, the longest distance any vehicle has ever traveled on another planet, moon or cosmic body. The previous record holder was Soviet Union's Lunokhod 2 rover, which traversed 24.2 miles across the moon's surface in 1973.
"This is so remarkable considering Opportunity was intended to drive about one kilometer and was never designed for distance. But what is really important is not how many miles the rover has racked up, but how much exploration and discovery we have accomplished over that distance."
And while it might be tempting to gloat, given the political tensions between the U.S. and Russia, NASA's scientists have been rather reverential.
"The Lunokhod missions still stand as two signature accomplishments of what I think of as the first golden age of planetary exploration, the 1960s and '70s," explained Steve Squyres, a researcher at Cornell University and principal investigator for NASA's Opportunity and Spirit rovers. "We're in a second golden age now, and what we've tried to do on Mars with Spirit and Opportunity has been very much inspired by the accomplishments of the Lunokhod team on the moon so many years ago. It has been a real honor to follow in their historical wheel tracks."
NASA's engineers hope Opportunity still has some life left. If the rover makes it to its next investigation point, it will have traveled 26.2 miles -- the distance of a marathon. Scientists have appropriately named this stop "Marathon Valley." Once there, Opportunity will study several clay minerals that are exposed in close proximity.