Mars Rovers Keep on Tickin'

Sept. 26, 2006 — -- It is the little Rover that could -- a little cosmic riding lawn mower that is about to unlock Victoria's secret.

When NASA landed the two Mars Exploration Rovers, Spirit and Opportunity, on Mars in 2004, they were expected to last 90 days at most.

But more than 900 days later, they are still going strong.

Steve Squyres, the lead Rover researcher, said, "I keep thinking this can't possibly get any better, and it just does."

The trick seems to be that stiff Martian wind that keeps dust off the solar panels so the Rovers can keep getting energy.

That energy doesn't just power the wheels, it also heats the Rovers in the Martian nights, which can get as cold as 150 degrees below zero.

"The first thing you've got to realize is that the vehicle was designed to go 600 yards -- about that far," Squyres said. "But the Rovers have now each traveled miles."

It hasn't been without a few close calls.

Opportunity got stuck in the sand one day, and Squyres said it was a pretty tense time for his research staff.

"We were all pretty confident that we'd be able to get out, but the first rule of a situation like that is, 'Do no harm.' Don't do anything dumb until you've analyzed the situation," he said. "We have Rovers on the ground -- here on Earth -- that are duplicates of what we have up on Mars, and we use them all the time."

But after hours of scientific pontification and research on Earth, Squyres said it was the common sense approach that ultimately broke the Rover free.

"We tried everything that you could imagine, different ways of operating the wheels and so forth," he said. "Turns out that after lots and lots of research, the optimal way is basically put it in reverse and gun it."

The Rovers' significance is almost undeniable.

They have already found some evidence that water -- a crucial building block of life -- once existed on Mars. This was a crucial discovery, Squyres says.

"If you can show that life arose independently on two different worlds, just in this one solar system … life might be common throughout the universe," he said. "So that's really important."