Mars Rover Sets Out on Risky Crater Mission

Cori Sue Morris
for National Geographic News

June 29, 2007

A seasoned explorer is about to embark on a new and dangerous mission.

NASA's Mars rover Opportunity, which has operated for more than 12 times its intended 90-day life span, will descend into the planet's enormous Victoria Crater late next week, mission scientists announced yesterday.

(See a map of Mars.)

The rover's old age poses potential problems for the mission, since the crater's steep sides and rough terrain could impair Opportunity's steering or damage its wheels.

Rovers do not need all six wheels to maneuver on flat terrain, but the crater's rocky slopes could present unusual hazards.

(See an aerial view of Victoria Crater.)

"If Opportunity were to lose the use of a wheel inside Victoria Crater, it would make it very difficult, perhaps impossible, to climb back out," said rover project manager John Callas at a press conference Thursday.

A current dust storm in the region could make the situation even riskier. The dust could block out sunlight, preventing the rover from generating solar power, the experts said.

The storms can also bring menacing mini-tornadoes, known as dust devils, which recently created problems for NASA's other rover, Spirit.

But the potential for scientific discovery is too great for NASA to pass up, the researchers said.

A layer of rock in the crater known as the Bright Band (pictured above) may contain valuable information about Mars's environment millions of years ago.

The layer was exposed to the Martian environment at the time of the crater's formation, so it could yield vital insights into the red planet's ancient atmosphere and water levels, the scientists said.

"We can't be certain about the terrains and footing until we go in there. But we know the rewards are worth the risk," said Alan Stern, NASA's associate administrator.

Opportunity will enter Victoria Crater at Duck Bay, said to be the safest location for descent. The mission will be what is known as a "toe dip," briefly entering near the crater's edge.

The rover's proximity to the crater's edge will allow scientists to address potential problems.

"If there are any issues in terms of performance, we are very close to the edge of the rim, so we are confident we can get back out again," Callas explained.

If the toe dip goes according to plan, Opportunity will head toward the Bright Band.

Reflecting on the dangers awaiting the elderly robotic explorer, Steve Squyres, principal science investigator for the rovers, said, "We want to get in and get out while we have a six-wheel rover. So if we're ever going to do it, now's the time."

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