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NASA has cleared a giant hurdle in landing a rover on Mars. USA TODAY's Dan Vergano and Robert Davis look at this new chapter in space exploration.
Q: Where is Spirit right now? A: As intended, Spirit appears close to the middle of Gusev Crater, a huge bowl that may have once held a lake. Scientists do know it rests upright — a very good thing — atop its landing craft and the deflated airbags that cushioned its landing. Q: What is it doing? A: The priority now is pinpointing the rover's position and its exact heading so that its high-power antenna — a lollipop-shaped object on its top — can be pointed toward Earth. That antenna will allow scientists to communicate directly with Spirit instead of using an orbiting craft as a go-between, as they were on Sunday. Scientists also say solar power is about 20% less than expected for Spirit because of the dust on Mars. They may change plans to deal with the shortfall. Q: How soon will it start driving around? A: It will start moving nine days after landing at best, NASA scientists say, so Jan. 13 would be the soonest for "egress," in NASA-speak, from the landing craft. When Spirit landed, it was folded up with its instruments turned off, so engineers and scientists are busy testing systems and limbering up the rover while plotting what path it should take on its three-month exploration. By Tuesday the rover should be up on its wheels. A 29-inch-high rock is on the right side of the landing craft, blocking one avenue to roll off, but overall the platform is tilted only about 2 degrees, convenient for egress. Q: Why did the rover land in a bouncing airbag instead of setting down with rockets as in the moon landings? A: Airbags remove the need for stabilizing rockets and electronics that make "soft" rocket landings possible; they were envisioned as a way to save weight and money for the 1997 Pathfinder mission. But the method has limits — it's imprecise, and at 400 pounds, Spirit is about the largest probe likely to try airbag landings on Mars, says landing expert Paul Withers of Boston University. NASA's next lander missions, scheduled for 2007 and 2009, are larger and will land with rockets. Q: Why did last month's Beagle 2 landing apparently go badly when this one went well? A: Most likely bad luck and fewer resources, Withers says. Any number of accidents might have occurred, but Beagle 2 lacked the stabilizing rockets Spirit had to combat winds, and its airbags were not the heavy-duty ones used by NASA, which might have left it vulnerable to damage. Q: What are scientists looking for with Spirit? A: Finding sedimentary rocks in what is believed to be a dried lake in Gusev Crater would be a first step. The rover might have to enter smaller craters to look for these layers of rock. A grinder would show cameras and other instruments whether Mars' water came from hot springs, a salty sea or some other source. Volcanic dust might have covered any sedimentary rock in the crater, and scientists hope examination of this rock tells them something about the geologic history of the Red Planet. Q: Can Spirit find the lost Beagle 2? A: No; if it indeed landed, it would be too far away, and scientists don't know where to look. Spirit mission manager Mark Adler says it would take "1,000 years" for the rover to reach Isidis Planitia, the flat basin where Beagle 2 was supposed to have landed. Q: Does Spirit's landing mean that the Opportunity rover scheduled to land Jan. 24 also will land safely? A: Not surprisingly, NASA officials are cautious and say Spirit's landing went far better than expected. But new stabilizing rockets and landing camera systems performed better than expected, "which gives everybody very high confidence," says Louis Friedman, head of the Planetary Society, a space exploration advocacy group whose companion event to the Spirit landing in Pasadena drew a standing-room-only crowd of 2,000. Q: What are the "Sol" days that scientists mention when they say what time it is on Mars? A: A Sol is a Martian day: 24 hours, 39 minutes, 35 seconds. About 40 members of the rover science team will be living on a "Sol" schedule, instead of Earth time, during the mission. Q: Where is Opportunity headed? A: Meridani Planum, a smooth equatorial plain marked by deposits of gray hematite, an iron oxide mineral usually associated with water on Earth. Once again, NASA is trying to "follow the water" in its exploration of Mars. |
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