Five Years Later, Mars Rovers Continue to Make Discoveries

In a study published Thursday in the journal Science, researchers analyzing that data have found evidence that an entire Oklahoma-sized region of Mars called the Meridiani planum was shaped by years of wind and water flows.

The new data come from the Victoria crater, a 2,400 foot wide area about four miles south of the Endurance crater, the first region that Opportunity explored. The pattern of rock layers that Opportunity first saw in the Endurance crater in 2004 suggested that ancient water flows had sculpted the region's surface.

But until the rover had a chance to explore more of the surrounding area, scientists couldn't be sure that the pattern would be repeated all over the region -- it might have been unique to the Endurance crater. The new information from the Victoria crater, which showed similar patterns, helps put that question to rest.

"It's hard to extrapolate from a single data point," says Steven Squyres, the principal investigator of the Mars rover mission. "This gives us confidence that these processes operated over the whole region."

Opportunity is a thorough but slow traveler. The rover took 21 months to traverse the nearly four miles between the Endurance and Victoria craters, and has spent two years examining the Victoria crater.

Its next stop is the crater Endeavor, some eight miles away.

"It's going to be a long, arduous drive," Squyres says. "We've been there five years, and we've gone 16 kilometers (9.9 miles) total [...] now we're going 13 more."

The trip's perils are illustrated by the predicament that Opportunity's twin rover, Spirit, is currently in. Two weeks ago, Spirit's wheels got stuck in an "insidious invisible rover trap" of sandy soil, as Squyres described it to Space.com, and NASA scientists are still working to free the rover from the dirt.

Opportunity's long trip will be worth it, Squyres says, because Endeavor is an older crater than either Victoria or Endurance, with very different features -- the scientists hope to get a look at the bedrock that lies beneath the sedimentary rock they've seen in the previous craters.

For now, though, they're just hoping that Opportunity holds out long enough to make the trip. The rovers were originally designed to last a minimum of three months. The mission has been extended five times as the rovers have continued to prove their hardiness.

"They're going to die when they die," Squyres says. "Every day is a gift."