On firm dirt, Rover ready to paw Mars

Moreover, as time passes, the rover will "learn" to drive itself. Later in the mission, Cooper will simply direct the rover where to go and the rover itself will decide how to get there.

The list of things that Spirit can study is limited predominantly to rocks and soil. But Spirit's instruments were designed specifically to wring science from the smallest grain of dust or pattern in a rock.

"It's in the subtleties that all the information will come," says Bruce Betts, a scientist at the Planetary Society here.

Scientists have never had a thermal emission spectrometer on the surface of an extraterrestrial planet before, and its images could show traces of minerals that form with water. Spirit's grinding wheel can shave fractions of an inch off rocks, revealing older layers, and perhaps providing clues about what the region was like billions of years ago, when it was thought to be a lake. The microscopic imager will be the geologist's microscope, giving them a closer look at soils and minerals than ever before.

"It's amazing what a trained geologist can pick out," says Dr. Betts.

So far, the project scientists have their eyes on several prominent features east of the rover. As during Sojourner's mission, names are beginning to emerge. The large depression of wind-blown dust a short distance away is "Sleepy Hollow." Slightly nearer is the "Wasabi" rock pair, including one named "Sushi."

The rover will likely set off toward Sleepy Hollow, perhaps arriving there in a week to study soil samples. After that, it will move toward a crater 800 feet away. Its existence is a bit of geographical serendipity.

The one thing Spirit is not equipped to do is drill into the ground to look at deeper layers. The impact that caused the 650-foot-wide crater, however, has essentially done it for them. It sprayed the older and deeper dust and rock onto the surface, and scientists hope that evidence remains.

"As we drive toward it, we could see the progression of layers inverted," says Dr. Haldemann.

Once there, Haldemann and others envision peering into a depression perhaps more than 60 feet deep. If its sides are shallow, they might take Spirit inside.

With a top speed of just over 1.5 inches a second, Spirit isn't going anywhere fast, and its lifetime and range is anyone's guess. The original estimate was 90 days and 2,000 feet. Mission managers quietly expect more if all goes well. Yet the last item on their list could prove to be too great a challenge.

The mapping team estimates that a range of 300-foot hills lies roughly two miles east of Spirit. As the rover's mission winds down, it will turn toward them. Like a modern-day Tantalus story, Spirit will grow weaker and possibly die as the hills slowly fill more of its vision with intriguing vistas.

Chief scientist Steve Squyres boldly imagines views from a Martian hilltop, but even if Spirit ends up short, the trek could be one of the great dramas of space exploration. "It's going to be a shared adventure unprecedented in human history," Dr. Squyres said at a press briefing. "This is going to be a lot of fun."

Page: 1 | 2