NASA scientists believe their Opportunity rover landed in a 60-foot crater. If that is so, Mars has done them something of a favor.
It has dug a hole for them, so that, in the newest pictures, they can see a cross section of Mars and its geological history.
"There is a lot more coming," said Jim Bell, the Cornell University scientist who directed the design of the rover's cameras. "We could not be happier, more thrilled with what we are seeing in this really incredible landing site."
Opportunity's target site was a plain on Mars called Meridiani. It is about the size of Oklahoma, and it is of interest to scientists because orbiting probes suggest it is rich in a mineral called gray hematite. On Earth, hematite generally forms only if there has been liquid water leeching into the soil. Water, of course, would be a key ingredient in determining if Mars was ever friendly to life.
From Opportunity's first pictures, so far, so good. The ground around the ship has a layer of granular gray soil. Only beneath it — in places where the spacecraft kicked up dirt on landing — does one see Mars' familiar rusty red.
It is very different from the panorama sent three weeks ago by NASA's other rover, Spirit. When Spirit landed on the other side of Mars, it found a field of windblown rocks, surrounded by bright red soil.
To project scientists, the most intriguing feature from Meridiani so far is an outcropping of bright bedrock in the crater's wall, something never before seen on Mars. Normally, it would be buried in several feet of soil. By sheer luck, it is only a few yards from the Opportunity rover.
"You can actually, if you have bedrock, learn things about the relative ages of different rocks that you see," said Steve Squyres, the principal investigator for the rover missions. "What I thought was that we were going to land on the hematite-bearing stuff, and then we'd have to trundle around and try to find a hole so we could find the layered rock outcrops. Boom — they're both right in front of us."
Opportunity made landing on Mars look easy, but the engineers at mission control Saturday night know better. They were stone silent, some of them pacing or kneading their hands, until signals confirmed the ship was safely down.
"We're on Mars, everybody!" called out Rob Manning, the engineer in charge of the landing sequence.
Opportunity is proving itself the exception. This morning British scientists finally conceded they have lost their Beagle 2 lander, which ought to have arrived on Mars on Christmas morning. It has not been heard from since, and Colin Pillinger, the lead scientist, said, "We have to begin to accept that if Beagle 2 is on the Martian surface, it is not active."
Meanwhile, the Spirit rover still sits crippled by last week's computer problems. Engineers believe they are on their way to a solution, but at best, they still expect it to take weeks.
"It's kind of like we have a patient in rehab here and we are nursing her back to health," said Jennifer Trosper, the mission manager.
Success if far from assured, though. So the scientists at NASA are very grateful for their new Opportunity.