Spirit Restored; Opportunity Set to Roll Onto MarsSat 31 January, 2004 00:55
By Gina Keating
PASADENA, Calif. (Reuters) - The Mars rover Spirit appeared on Friday to have returned to normal operations about 10 days after it was crippled by a problem with its computer memory, the mission's chief flight software engineer said.
Glenn Reeves said Spirit's apparent return to good health came after engineers deleted about 1,700 non-essential files from the rover's computers and rebooted it in "normal mode."
The engineers had ordered the rover to remain in "crippled mode" to prevent it from further harming itself while they tried to figure out why it was endlessly resetting itself.
"I'm pleased to report that it seems to be working fine," Reeves said. "We alleviated the problem."
He said mission control at NASA's Jet Propulsion Laboratory in Pasadena was still awaiting data from Spirit to confirm that the rover was ready to resume scientific activities that were interrupted by its malfunction.
Spirit was examining a football-shaped rock nicknamed Adirondack on Jan. 22 with scientific instruments mounted on its robotic arm when NASA engineers believe some of its flash memory malfunctioned.
Reeves said Spirit's memory held about 13,000 files containing scientific and other data gathered during its 27 days on Mars when it crashed, possibly because the memory was overloaded.
He said Spirit would transmit much of that information to Earth on Friday and Saturday, and the rest would be erased when the rover's computer is reformatted on Saturday.
Both Spirit and its twin, the rover Opportunity, were under new orders to limit the number of files stored in memory, he said.
NASA scientists on Friday readied Opportunity to roll off its landing platform overnight onto the gray plain where it landed on Saturday near the equator of Mars.
The golf cart-sized Spirit and Opportunity are each equipped with a mobile laboratory of geologic tools designed to search for evidence that the barren martian surface was once wetter, and possibly more hospitable to life, than it is now.
Opportunity has moved through its landing and egress steps nearly twice as fast as Spirit, which landed on the other side of the planet on Jan. 3 and rolled off its lander onto Gusev Crater 12 martian days, or sols, later.
Engineers planned on Friday, or sol 7, to cut the last cable attaching Opportunity to the lander and commanding the rover to drive down the front ramp at 12:30 a.m. (3:30 a.m. EST/0830 GMT) on Saturday, the end of sol 7, rover systems engineer Daniel Limonadi said.
"At this point we have a very benign egress path so we're not too worried," Limonadi said.
Engineers were still contending with an unexpected power drain from one of the craft's heating units that keeps turning itself on and running overnight without receiving commands from NASA to do so.
Opportunity landed on Jan. 24 on the smooth, flat Meridiani Planum inside a small crater -- 20 meters (66 feet) wide and 3 meters (10 feet) deep -- a short distance from an outcropping of pale bedrock.
Rob Manning, entry, descent and landing manager, said on Friday that his team was still puzzling over telemetry data to pinpoint the rover's exact position on Mars. Manning said the rover may have bounced as many as 30 times, and appeared to be at least 15 kilometers (9.3 miles) downrange from where navigators believed it would land.
"We are doing a lot of guessing," Manning said. "We still don't know where the hell we are."
After sampling the soil on the crater floor with an array of scientific instruments, Opportunity probably will head toward the outcropping, which lies less than 10 yards away from the lander, Ray Arvidson, deputy principal investigator, said.
Arvidson said scientists were "ecstatic" that Opportunity's mini-thermal imaging spectrometer (mini-TES) seems to have confirmed the presence of the iron-bearing mineral gray hematite near the bedrock.
The hematite deposit, about the size of the U.S. state of Oklahoma, was first detected by the orbiter Mars Global Surveyor and figured heavily in the choice of landing sites.
On Earth, hematite usually forms in iron-rich lakes or oceans, but can also arise from direct oxidation of iron-rich lava, JPL officials said.
Once Opportunity's roll-off is complete and Spirit is found to be back in working order, both rovers should be operating simultaneously on Mars for the first time.