NASA Declares the Mars Spirit Rover to be Healed
By ANDREW BRIDGES
PASADENA, Calif. (AP) — NASA’s Spirit rover was declared cured Friday after repair of a problem with its computer’s flash memory system that stalled the wheeled robot for two weeks and threatened its mission to search for geologic evidence that Mars was once wetter and hospitable to life.
“I think I can say this morning with as much certainty as we can say anything here that our patient is healed,” Spirit mission manager Jennifer Trosper told a Jet Propulsion Laboratory news conference.
The rover, which was described as being in critical condition when it abruptly stopped sending science data to Earth, this week underwent a delicate process of deleting files and reformatting the flash memory. The craft was able to resume science work on Thursday.
Trosper said the long-distance repair job was nerve-racking “but in the end the spacecraft did exactly what we wanted it to do, and it performed perfectly and it’s in great health right now.”
The problem was simply accumulation of computer files that kept consuming the spacecraft’s memory “and eventually we ran out,” said Glenn Reeves, the flight software architect.
The computer software detected the consumption of the memory as “a very severe error” and behaved properly in trying to solve the problem by resetting itself, but instead that triggered a cascade of resets. Each time the system came back up it would detect the same severe error and reset.
Spirit and its twin, Opportunity, which is on the other side of the planet, are now being monitored to prevent accumulation of files in their memories.
Opportunity, was continuing to work well, scientists said.
NASA on Thursday sent Opportunity on a roll across a pebbly patch of Mars, moving the rover closer to a rock outcrop that scientists want it to spend several days studying in detail.
The 11-foot drive put the wheeled rover within striking distance of the rocky portion of the rim of the 72-foot wide crater in which it landed late last month. The move was Opportunity’s first since it rolled off its lander Saturday.
Opportunity needed to roll at least five more feet to put the slabs of bedrock within reach of its robotic arm, and a final “scoot” might be necessary to move the rover even closer, said scientist Larry Soderblom, of the U.S. Geological Survey.
Scientists skipped plans for the rover to dig into and analyze the martian soil on the way, opting instead to reach as quickly as possible a feature on the outcrop they have nicknamed “Snout.”
“Once we get there, we are going to do some pretty heavy remote sensing. It will be our first really good look at the outcrop,” said the mission’s main scientist, Cornell University astronomer Steve Squyres.
Opportunity’s keen-eyed cameras have already revealed fine-scaled layering in the rock formation, which could have been laid down in water. Its instruments should shed further light on the origin of the layers. NASA sent Opportunity and its twin, Spirit, on the $820 million mission to find geologic evidence of past water activity on Mars.
Spirit could begin rolling again by the weekend, moving toward a crater 800 feet away that could take a month to reach.
Scientists planned for Opportunity to spend several days at “Snout” and several more cruising alongside the band of rocks, Soderblom said.
Then Opportunity may turn its attention to the martian soil, spinning one of its front wheels to dig into a spot rich in the iron-bearing mineral hematite. Opportunity previously looked at a patch of soil elsewhere in its crater that contained very little of the iron oxide, which typically forms in liquid water.
Once done, Opportunity may turn back to the outcrop and re-examine select spots in further detail, Soderblom said.
“This is a very dynamic process,” Squyres said.
NASA also has pinpointed where Opportunity landed late last month, Theisinger said. The rover sits inside a shallow depression about 2,300 feet west of a larger crater, he said.
About the Mars Exploration Rover Missions
NASA’s twin robot geologists, the Mars Exploration Rovers, launched toward Mars on June 10 and July 7, 2003, in search of answers about the history of water on Mars. They are scheduled to land on Mars January 3 and January 24 PST (January 4 and January 25 UTC).
The Mars Exploration Rover mission is part of NASA’s Mars Exploration Program, a long-term effort of robotic exploration of the red planet.
Primary among the mission’s scientific goals is to search for and characterize a wide range of rocks and soils that hold clues to past water activity on Mars. The spacecraft are targeted to sites on opposite sides of Mars that appear to have been affected by liquid water in the past.
The landing sites are at Gusev Crater, a possible former lake in a giant impact crater, and Meridiani Planum, where mineral deposits (hematite) suggest Mars had a wet past.
After the airbag-protected landing craft settle onto the surface and open, the rovers will roll out to take panoramic images. These will give scientists the information they need to select promising geological targets that will tell part of the story of water in Mars’ past. Then, the rovers will drive to those locations to perform on-site scientific investigations over the course of their 90-day mission.
These are the primary science instruments to be carried by the rovers:
– Panoramic Camera (Pancam): for determining the mineralogy, texture, and structure of the local terrain.
– Miniature Thermal Emission Spectrometer (Mini-TES): for identifying promising rocks and soils for closer examination and for determining the processes that formed Martian rocks. The instrument will also look skyward to provide temperature profiles of the Martian atmosphere.
– Mössbauer Spectrometer (MB): for close-up investigations of the mineralogy of iron-bearing rocks and soils.
– Alpha Particle X-Ray Spectrometer (APXS): for close-up analysis of the abundances of elements that make up rocks and soils.
– Magnets: for collecting magnetic dust particles. The Mössbauer Spectrometer and the Alpha Particle X-ray Spectrometer will analyze the particles collected and help determine the ratio of magnetic particles to non-magnetic particles. They will also analyze the composition of magnetic minerals in airborne dust and rocks that have been ground by the Rock Abrasion Tool.
– Microscopic Imager (MI): for obtaining close-up, high-resolution images of rocks and soils.
– Rock Abrasion Tool (RAT): for removing dusty and weathered rock surfaces and exposing fresh material for examination by instruments onboard.
A goal for the rover is to drive up to 40 meters (about 44 yards) in a single day, for a total of up to one 1 kilometer (about three-quarters of a mile).
Moving from place to place, the rovers will perform on-site geological investigations. Each rover is sort of the mechanical equivalent of a geologist walking the surface of Mars.
The mast-mounted cameras are mounted 1.5 meters(5 feet) high and will provide 360-degree, stereoscopic, humanlike views of the terrain. The robotic arm will be capable of movement in much the same way as a human arm with an elbow and wrist, and will place instruments directly up against rock and soil targets of interest.
In the mechanical “fist” of the arm is a microscopic camera that will serve the same purpose as a geologist’s handheld magnifying lens. The Rock Abrasion Tool serves the purpose of a geologist’s rock hammer to expose the insides of rocks.
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