Mars Dust Storm Cripples Rovers

July 5, 2007 — A huge dust storm on Mars has cut power to NASA's twin roving geology stations and delayed the start of an investigation into a large impact crater that bears an unusual ring around its inner walls.

The Spirit and Opportunity rovers, which have been exploring opposite sides of the planet's equatorial region for three and a half years, charge their batteries with solar panels that need direct sunlight.

But a massive dust storm, estimated to be thousands of miles wide, has blanketed the rovers with dust and impaired their ability to collect sunlight.

Opportunity was scheduled to descend into Victoria Crater this week, but the study is on hold until the storm clears and the rover's power is restored. NASA hopes the descent into the crater can begin as early as July 13.

"We may have passed the worst of this," said rover mission manager John Callas, with NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The situation could improve quickly, but we will have to wait and see."

The storm, which had been brewing for more than a week, already has spread eastward and is now affecting Spirit's operations in Gusev Crater.

Both rovers are hunting for signs of past water.

The storm is the most intense to hit Mars since the rovers landed. Opportunity's measurements of atmospheric opacity swelled from 1.0 to 3.3, while solar power dropped from 764 watts to 402.

"While this only represents enough dust to coat the planet to about the thickness of a human hair, it is enough to decrease the brightness of the noon sun by 96 percent compared to a completely clear atmosphere," said rover lead investigator Steve Squyres, with Cornell University.

"We have not seen dust measurements this high on either rover before," Callas added. "If the dust levels were to increase further and stay elevated for several days, there is a risk to how well Opportunity could continue to work in this darkened environment."

Scientists are eager to get Opportunity into Victoria Crater to study a bright ring of material that could hold chemical signs of past water, which is believed to be a key ingredient for life.