Diagasm NASA celebrated a milestone in space exploration on Tuesday when the Opportunity Mars rover's odometer clicked past 26.219 miles (42.195 kilometres) – marking the first time a man-made object has completed a marathon's distance on the surface of another planet.
"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," said Steve Squyres, Opportunity principal investigator at Cornell University in Ithaca, New York. "Still, running a marathon on Mars feels pretty cool."
It has taken the rover eleven years and a little over two weeks to make the distance, which isn't bad for a machine that was built to last for just 90 days. The timescale was based on a flawed assumption however.
NASA scientists had assumed – based on our experiences on the Moon – that Martian dust would cling to the rover's solar panels, degrading their ability to recharge the machine's batteries. In fact, the Martian winds give the rover regular cleaning sessions, enabling it and its sister bot Spirit to carry on truckin' across the Red Planet's surface.
Once the agency realized the rovers were going to be around a lot longer than expected, the mission was repurposed. Both rovers were on Mars to look for evidence of water on the harsh alien world, and the extended lifespan of the machines allowed much more scientific data to be collected.
The Spirit rover got caught in a sand dune in 2009, and despite the best efforts of NASA technicians, it was declared first a "stationary research station," and then simply shut down, having clocked up 4.8 miles (7.73 kilometers) before conking out.
Opportunity is still rolling, however. Since 2011 the rover has been exploring the rim of Endeavour crater, examining the exposed strata for evidence of sedimentary rock, giving boffins an insight into the Red Planet's geological history.
Quite how long the rover can continue is in question. The rover's flash memory is failing, its computer has been going through a series of restarts, and NASA technicians have tried to lobotomize parts of its memory, which has partially fixed the issue of storage degradation.
Nevertheless, Opportunity has lasted long enough to break the marathon mark, and hopefully it won't mimic Pheidippides and drop dead after going the distance. To mark the event, boffins at NASA's JPL will run a marathon relay race next week, so expect a lot of sweaty scientists on the streets of Pasadena, California.
"This is the first time any human enterprise has exceeded the distance of a marathon on the surface of another world," said John Callas, Opportunity project manager at NASA's Jet Propulsion Laboratory. "A first time happens only once." ®