By almost any measure, it was a spectacular week both in Pasadena, where the rover was birthed, and at Gusev Crater, Mars, where it now finds itself. NASA has been in need of redemption since the explosion of the shuttle Columbia last winter, and Spirit to say nothing of its sister ship, Opportunity, heading for its own Martian touchdown at the end of the month is it. The space agency's website recorded 1.45 billion hits in just over five days last week. The White House, perhaps sensing an election-year winner, announced that the President would soon deliver a long-delayed speech about the future of the space program, possibly including a return to the moon and a manned trip to Mars.
The real news, however, was made on the Red Planet. The 90-mile-wide Gusev Crater located about 15° south of the planet's equator resembles a dry lake bed, one that could easily have been drenched with water from what appears to be a 559-mile-long river channel entering it from the southeast. If there was once Martian water, it should have ponded there. If there was once Martian life, it might have called this great lake home.
That possibility, plus Gusev's relatively smooth, obstacle-free terrain, is why the crater presented such a tempting target and why NASA scientists are so thrilled that the spacecraft made it. "If you were looking for a place to land in the U.S., geologists would land in the Grand Canyon and engineers would land [in a plain] like Kansas," says paleontologist Andrew Knoll, a member of the rover long-range-planning team. "Gusev gives us both a congenial site for roving and still has a high probability of getting to good outcroppings."
Before Spirit can actually start to dig in the Martian sandbox, however, there are a few technical obstacles to overcome. Last week, mission managers discovered a worrisome spike in temperature within the guts of the rover during the Martian daytime, requiring them to periodically power down some instruments to give the machinery brief cooling naps. An electrical surge in the main antenna also caused concern, but so far it appears to have been a harmless hiccup.
More challenging is a problem with the landing platform something that could interfere with Spirit's very ability to move. The rover descended to the surface in a hard, three-petaled shell that was protected by the now famous swaddling of air bags. On the ground, the bags deflated and the petals opened, providing Spirit with three possible exit ramps onto the surface. The problem is, one of the ramps the best one, as it happens, since the rover does not have to turn around to reach it is partly obstructed by the collapsed bags.
A maneuver designed to lift the petal and retract the bag failed at the end of last week, and engineers are planning to have the rover exit down a rear ramp. Even if that one proves to be blocked too, it would still be possible to drive over the bags, though that is a risky move since the fabric may have stiffened in the extreme Martian cold and could damage or interfere with the craft's solar panels. In either event, no one at J.P.L. is remotely calling these problems mission-enders though no one expects the rover to be able to move off the lander much before the end of this week. "We have some very valuable assets on Mars," says J.P.L. director Charles Elachi. "Now is the time to be careful."
Whenever Spirit finally starts to travel, it will have no shortage of targets. The vehicle's nine cameras have been drinking in images of the surrounding terrain and beaming them back to Earth in brilliantly sharp resolution, sometimes even in 3-D. Every day six teams of J.P.L. scientists gather in a large, classroom-like office to study the pictures on several 6-ft.-wide projection screens, smaller laptop-size screens and flat electronic slates. What they have found has intrigued and in some cases mystified them.
Perhaps the most interesting spot on the surface is one the spacecraft created. As the bubble-wrapped craft bounced to a landing, it scuffed the ground at a point just south of where the rover now rests. The loose red soil it cleared away has revealed a dark patch of what resembles mud though that's impossible on the entirely waterless floor of Gusev.