2 September 2011

New Mars site more favourable for life

Agence France-Presse
A new site on Mars has yielded soil samples unlike any examined before on the red planet, and that appear more favourable for life.
Mars Exploration Rover Opportunity

NASA's Mars Exploration Rover Opportunity used its front hazard-avoidance camera to take this picture showing the rover's arm extended toward a light-toned rock, 'Tisdale 2', during the 2,695th Martian day, or sol, of the rover's work on Mars. Credit: NASA/JPL-Caltech

WASHINGTON: A new site on Mars has yielded soil samples unlike any examined before on the red planet, and that appear more favourable for life.

The site is being examined by NASA’s rover Opportunity, that has been exploring Mars for seven and a half years. It arrived three weeks ago at the edge of a 22-km-wide crater named Endeavour and has been sending back images of the surrounding environment.

The first rock it examined, named Tisdale 2, is a flat-topped object about the size of a footstool that apparently was cast up by an impact that left an impression the size of a tennis court on the rim of the crater.

“This is different from any rock ever seen on Mars,” said Steve Squyres, principal investigator for Opportunity at Cornell University in Ithaca, New York. “It has a composition similar to some volcanic rocks, but there’s much more zinc and bromine than we’ve typically seen. We are getting confirmation that reaching Endeavour really has given us the equivalent of a second landing site for Opportunity.”

Wetter conditions

The observations and measurements taken by the American Martian orbiters leads scientists to believe that the rocks on the rim of the crater contain clay minerals that form in wet conditions and which are less acidic and possibly more favourable for life, they said.

The ridge around the edge of the crater is named ‘Cape York’, and a gap between Cape York and the next rim fragment to the south is called ‘Botany Bay’.

“On the final traverses to Cape York, we saw ragged outcrops at Botany Bay unlike anything Opportunity has seen so far, and a bench around the edge of Cape York looks like sedimentary rock that’s been cut and filled with veins of material possibly delivered by water,” said Ray Arvidson, the rover’s deputy principal investigator at Washington University in the U.S.

During the past two weeks, researchers have used an instrument attached to Opportunity’s robot arm to identify the elements that make up the rock.

30 times longer

The team selected Endeavour as Opportunity’s long-term destination after the rover climbed out of Mars’s Victoria crater three years ago this week. The mission spent two years studying Victoria, which is about one twenty-fifth as wide as Endeavour. Layers of bedrock exposed at Victoria and other locations Opportunity has visited share a sulfate-rich composition linked to an ancient era when acidic water was present. Opportunity drove about 21 km from Victoria to reach Endeavour. It has driven 33.5 km since landing on Mars.

“We have a very senior rover in good health for having already worked 30 times longer than planned,” said John Callas, project manager for Opportunity at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

“However, at any time, we could lose a critical component on an essential rover system, and the mission would be over. Or, we might still be using this rover’s capabilities beneficially for years. There are miles of exciting geology to explore at Endeavour crater.”

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