The golf-cart-size Opportunity rover has now traveled 26.221 miles (42.198 kilometers) since touching down on the Red Planet on Jan. 24, 2004, NASA officials announced today (March 24). The length of a marathon race is 26.219 miles (42.195 km).
"This is the first time any human enterprise has exceeded the distance of a marathon on the surface of another world," John Callas, Opportunity project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, said in a statement. "A first time happens only once." [Inside Opportunity's Record-Setting Mars Marathon (Infographic)]
Opportunity reached the milestone with a 153-foot (46.5 meters) drive today that took it close to a location dubbed Marathon Valley, located on the rim of Endeavour Crater. The six-wheeled robot has been exploring the 14-mile-wide (22 km) crater's western rim since August 2011.
Opportunity adds to its off-world driving record with every turn of its wheels. Second place belongs to the Soviet Union's Lunokhod 2 rover, which covered 24.2 miles (39 km) on the moon back in 1973.
"This mission isn't about setting distance records, of course. It's about making scientific discoveries on Mars and inspiring future explorers to achieve even more," Steve Squyres, Opportunity principal investigator at Cornell University in Ithaca, New York, said in the same statement. "Still, running a marathon on Mars feels pretty cool."
Opportunity landed three weeks after its twin, Spirit, on a mission to search for signs of past water activity onMars. Both rovers found plenty of such evidence, fundamentally reshaping scientists' understanding of Red Planet history, and the rovers then kept chugging along.
Spirit stopped communicating with Earth after getting bogged down in some loose sand in 2010 and was declared dead a year later. Opportunity remains active, though it has been showing signs of its advanced age. The rover's robotic arm is arthritic, for example, and engineers recently installed a software upgrade to deal with a memory issue that had been afflicting Opportunity since late 2014.
Opportunity is currently studying a small crater called Spirit of St. Louis, which lies just west of Marathon Valley. NASA's Mars Reconnaissance Orbiter has spotted signs of clay minerals, an indication of a wet past environment, in Marathon Valley, and the rover team plans to check out these deposits soon.
Opportunity team members will hold a marathon-length relay race next week at JPL to celebrate the driving milestone, NASA officials said.
- Distances Driven on Other Worlds (Infographic)
- Opportunity Rover Breaks Off-World Driving Record | Video
- Top 10 Discoveries by Mars Rovers Spirit & Opportunity: A Scientist's View
Copyright 2015 SPACE.com, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.