Mars dust storms suck life out of rovers

By Dave Mosher

updated 2:27 p.m. ET July 20, 2007

A raging dust storm on Mars has cut power to NASA's twin rovers to dangerously low levels, threatening an end to the mission.

The rovers were slated to operate for only three months but have been on Mars more than three years, so mission officials have had ample time to ponder their silencing.

The storm presents perhaps the rover team's biggest challenge, NASA said in a statement Friday. Scientists said the storm, which has been brewing for nearly a month, is blocking around 85 to 90 percent of all sunlight to the surface.

The rovers, Opportunity and Spirit, rely on sunlight to charge their solar panels, and one or both rovers could be damaged permanently or even disabled by the limited solar power, officials said.

Space.com reported the storm's fresh severity earlier Friday.

Days or weeks to go
Scientists fear the storms might continue for several days or weeks. If the sunlight is further slashed for an extended period, the rovers will not be able to generate enough power to keep warm and operate at all, even in a near-dormant state, the statement said.

The rovers use electric heaters to keep vital core electronics from becoming too cold.

"We're rooting for our rovers to survive these storms, but they were never designed for conditions this intense," said Alan Stern, associate administrator of NASA's Science Mission Directorate.

"To give you a sense of the 'thickness' of the dust, the brightness of the sun as viewed from the surface is now down to less than 5 percent of what it would be with a perfectly transparent atmosphere," said Steve Squyres of Cornell University, who is the lead scientist of the Mars Exploration Rover project. "Of course, Mars never has a perfectly transparent atmosphere, but the sun is still very faint."

The rovers' scientific operations were stopped Wednesday.

"This is, I think, one of the most significant challenges we've faced over this entire mission," Squyres told Space.com. "The nature of the risk is well understood, but the magnitude of the risk is not. We simply don't know what's going to happen next."

Martian weather is unpredictable, in part because there are few monitoring instruments and no formal weather forecasting agency as on Earth.

"Whatever we do, though, the problem is not going to get much better rapidly," Squyres said. "I think that we have a good chance. If Mars really wants to kill these vehicles it can, but we have a lot of things working in our favor."

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