Mars rover prepares to roll off lander
Spirit will touch ground, then 'head for the hills'
By Kate Tobin
CNN
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This snippet of a panoramic color photo from Mars shows 'Sleepy Hollow,' a depression that the NASA rover Spirit may explore.
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Pandemonium erupts as Spirit makes a safe landing on Mars.
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(CNN) -- Mission managers are making final preparations to roll the Mars rover Spirit off its lander later this week, among them cutting the last cable tying it down.
"Today was a fantastic day," Flight Director Chris Lewicki said Tuesday. "The big end point of the day is that Spirit is a rover."
By that, he meant that Spirit made its first short drive, a distance of just one foot, backing up onto the lander's deck. It also executed a 45 degree turn in place, the first of three turns necessary to position it to exit the lander.
If all goes as planned, "egress" will begin at 1 a.m. Thursday ET, with mission controllers commanding the rover to move three meters down a ramp and onto Martian soil.
"The most dangerous driving we're going to do on the surface is the first three meters," Lewicki said. "Our own lander is the most dangerous obstacle, so we need to be very careful."
Once on the ground, Spirit is expected to start analyzing rocks near the lander, and eventually make its way toward a large crater about 300 feet away.
Project scientists have likened Spirit to a robotic geologist. The rover's mission is to study rocks and soil in an effort to determine whether the cold, desert Martian world once was a warm, wet planet. After exploring near the crater, the rover will "head for the hills," making its way toward an area scientists call the "East Hill Complex."
"I cannot tell you that we are going to reach those hills," said Steve Squyres, the mission's principal investigator. "This vehicle was designed, our requirement for how far we should be able to traverse over the course of the mission, was 600 meters. These hills are five times that far away. OK, so don't sit here and think, 'Oh, we're going to the hills.' We're going to go 'toward' the hills."
On Tuesday, NASA also released additional details about the spacecraft's landing January 3.
Rob Manning, who oversaw the landing of the spacecraft, said his team has been studying data collected by Spirit as it parachuted into the Martian atmosphere and then bounced to a landing on the surface, cocooned in a shell of airbags.
His group is analyzing the data to tweak the landing plan for the Mars Opportunity Rover, set to land on the other side of the planet January 24.
Spirit's parachute opened 4.6 miles above the Martian ground as the craft traveled 920 mph. The parachute slowed the descent rate to 152 mph --slower than expected.
"[At] 152 miles per hour, the vehicle is actually going 30 miles per hour faster than a skydiver with the parachute open," Manning said. "So we are going very fast, and in fact in our animations, some of the early animations we've been working on, you can see the ground coming toward you, and you realize robots have nerves of steel ... or copper as the case may be. It is nerve-racking to see the ground come at you that fast. But it worked fine, apparently."
Braking rockets fired as planned, and the lander bounced 28 times before coming to rest in its target zone: the Gusev Crater, a nearly 100-mile-wide pockmark just south of the Martian equator.
Spirit and Opportunity have considerably more mobility and capability than the most recent craft to make it to Mars. The 1997 NASA mission to the red planet included the Pathfinder lander, which beamed back thousands of images, and Sojourner, a toy-size test rover that scurried around the rocks and boulders strewn on the landing site.
Each of the new rovers, however, is built to explore nearly as much territory in several days as Sojourner covered in three months -- about 100 yards. Each comes equipped with eight cameras that can provide panoramic images of the Martian surface, with resolution so sharp they retain crisp detail when blown up to the size of a movie screen, according to NASA.
The rovers' microscopes, spectrometers and drills could unlock geologic secrets from billions of years ago, when scientists think conditions on the planet may have been more suitable for life.
-- CNN.com's Richard Stenger contributed to this report.
