Risky descent planned for Mars crater
By Michael Coren
CNN
 |  The enhanced color image from the rover Opportunity looks down the slope of Endurance crater from its rim. |
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 Mars rover Opportunity to explore Endurance crater. (May 7)
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NASA decided to roll the dice on Mars this Tuesday by dispatching its rover Opportunity into a crater from which it may never escape.
Endurance crater -- with its treacherously steep slopes and sandy sides -- has intrigued scientists with rock faces that reveal what appear to be layers of sedimentary rock.
Scientists at NASA's Jet Propulsion Laboratory said the knowledge to be gained from the excursion outweighs potential risks to the rover.
Whether Opportunity's gamble ends in success or failure, science will come out the winner, said Steve Squyres, principal investigator of the mission.
"The biggest risk we've got here is that we will be stuck in the candy store for the rest of the mission," said Squyres.
The geology of Endurance crater promises to open a window into Martian history that surface studies have only glimpsed. The Mars rover team has targeted a rocky outcrop called Karatepe about 20 feet from the rim.
This will be the closest scientists have ever gotten to this kind of geological formation on Mars. Further study could shed light on how the apparently sedimentary rock -- laid down by wind, water or ice -- formed on ancient Mars. The plan calls for Opportunity to study the formation for several days before exiting the crater and continuing on its mission.
"It's literally a win-win situation," said Squyres. "This is a really good move."
But NASA engineers said they would not tempt fate.
"A cautious path gets us [to the target site] Tuesday of next week," said Jim Erickson, deputy manager for the Mars rover project.
On Tuesday, Opportunity tested its wheels by driving just over the lip of the crater and pulling back to the rim. Engineers will study how well the rover gripped the soil before sending Opportunity back down the sandy slopes.
"As we speak, the rover is going into the crater and back out," said Erickson during a Tuesday press conference at the Jet Propulsion Lab in Pasadena, California. "When we back out we are going to take a look at the soil the rover has come in contact with."
Tests on Earth have reassured scientists that they have a significant safety margin to enter the crater along its planned route down a 20-degree slope. Controllers will attempt to keep the six-wheeled rover on rocky terrain and maintain traction rather than risk being bogged down on the crater floor. The depression measures about 490 feet (150 m) in diameter and 66 feet (20 m) deep.
NASA is trying to extend its spectacular winning streak on the Red Planet. The rovers exploring the Martian surface have already revealed a suite of discoveries about the history of Mars.
Evidence of salty pools of water, surface streams and a once wetter more hospitable climate have excited scientists looking for signs that life could have once flourished on our planetary neighbor.
Both rovers are now well into what scientist are calling "bonus time," beyond their primary mission time of about three months.
Opportunity finished its primary mission on April 26, its 90th full day on Mars. It has trekked about 1 mile (1.4 km) since landing. Its sister rover, Spirit, is now 2 miles (3.2 km) into its own planetary walk-about.
Spirit recently dug a trench that revealed high levels of magnesium and sulfur, suggesting water once percolated through the soil and evaporated leaving salts. Spirit is now closing in the Columbia Hills which promise to offer even more insights into Martian geology.
