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Articles: New Crater Beckons Mars Rover

Posted by admin on Friday, May 07, 2004 - 12:27 AM

Perched on the edge of a 430-foot-wide crater, the Mars rover Opportunity has spied a new treasure trove of rocks that promise to tell a richer, deeper story of the planet's geological past.
At a news conference yesterday at NASA's Jet Propulsion Laboratory in Pasadena, Calif., Dr. Steven W. Squyres, the mission's principal investigator, called a high-resolution color panorama "surely the most spectacular image yet from this mission." The photograph of the crater, named Endurance after Sir Ernest Henry Shackleton's ship in the 1914 expedition to Antarctica, is spectacular not just for "sheer scenic grandeur," Dr. Squyres said, but "also for the scientific potential that it offers." The Opportunity will spend several weeks circling the outside of Endurance as mission managers try to figure out whether the rover can safely enter it and, more uncertain, make its way out again. The crater is up to 66 feet deep, with slopes of 20 degrees and steeper. But Dr. Squyres said it was conceivable that the Opportunity would be sent in, even if mission managers were convinced it would be a one-way trip. The scientists want to examine the crater's bedrock close-up with a suite of instruments on the rover. The $835 million mission of the Opportunity and the Spirit, its twin on the other side of Mars, is to look for signs that the planet was once much warmer and wetter, perhaps even amenable to life. Both rovers are to operate through at least September. Based on the analysis of bedrock of the small crater that it landed in, the Opportunity has already discovered compelling evidence that the vast, flat plain Meridiani Planum was once a salty sea. The Opportunity crawled out of the first crater, Eagle, in March, headed east toward Endurance crater, almost a half-mile away. It arrived last Friday. Since then, it has been taking photographs and measurements. Endurance crater exposes the same bedrock layers seen previously, but also reveals deeper layers that could tell what existed there before the sea. "We see enormous outcrops," Dr. Squyres said, "much bigger than anything we've seen before of layered rock." In the Eagle crater, about a foot of bedrock was exposed. In Endurance, bedrock yards high is visible. "Here, there are cliffs that the rover could fall off and die if we're not careful," Dr. Squyres said. The mineralogy of the lower rock layers appears markedly different, Dr. Squyres said, rich in basalt and lacking the sulfates seen in the upper layers, and there are hints in the photographs of large angled layers that may be the remains of sand dunes that turned to stone. "We're going to be looking for evidence of a beach environment — was there something like that going on?" Dr. Squyres said. "I don't know what it's going to be, but it ain't what we saw back at Eagle. It's something different."

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