|Volume: 02, Issue: 03||02/11/2004|
Spirit Breaks Record as Opportunity Continues to ExploreWhile NASA's Opportunity rover continues to explore the Martian terrain, its twin, Spirit, has returned to full health and has broken a record for distance traveled on one sol, or Martian day.
On its 37th sol on Mars, which ended at 6 a.m. PST on Feb. 9, Spirit broke the record for the farthest distance driven in one sol on Mars, traveling 21.2 meters (69.6 feet). This distance traveled shattered the Sojourner rover's previous record of 7 meters (23 feet) in one sol.
The broken record is a huge step for the Spirit team, who just recently recovered from a temporary loss of communications on January 22; the problem was later diagnosed as a memory-management issue. Engineers regained partial control of the spacecraft within days and reformatted Spirit's flash memory February 4 to prevent recurrence of the problem.
"Our patient is healed, and we're very excited about that," said Jennifer Trosper of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, mission manager for Spirit.
Spirit's first day of science operations after the memory reformatting featured the first brushing of a rock on a foreign planet to remove dust and allow inspection of the rock's cleaned surface. Steel bristles on the rover's rock abrasion tool cleaned a circular patch on the rock unofficially named Adirondack. The tool's main function is to grind off the weathered surface of rocks with diamond teeth, but the brush for removing the grinder's cuttings can also be used to sweep dust off the intact surface.
One reason scientists first selected Adirondack for close inspection is because it appeared relatively dust free compared to some other rocks nearby.
"To our surprise, there was quite a bit of dust on the surface," said Dr. Ken Herkenhoff of the U.S. Geological Survey's Astrogeology Team in Flagstaff, Arizona, lead scientist for the rovers' microscopic imagers.
Examination of the freshly exposed interior with the rover’s microscopic imager and other instruments confirmed that the rock is volcanic basalt.
After examining Adriondack, Spirit drove about 6.4 meters (21 feet) testing the rover's autonomous navigation ability for the first time on Mars. In the coming sols, Spirit will continue its drive towards the crater nicknamed "Bonneville."
Meanwhile, halfway around Mars, Opportunity drove about 4 meters (13 feet) on February 9. It moved to a second point in a counterclockwise survey of a rock outcrop called "Opportunity Ledge" along the inner wall of the rover's landing-site crater. Pictures taken at the first point in that survey reveal gray spherules, or small spheres, within the layered rocks and also loose on the ground nearby.
NASA now knows the location of Opportunity's landing site crater, which is 22 meters (72 feet) in diameter. Radio signals gave a preliminary location less than an hour after landing, and additional information from communications with NASA's Mars Odyssey orbiter soon narrowed the estimate, said JPL's Tim McElrath, deputy chief of the navigation team.
As Opportunity neared the ground, winds changed its course from eastbound to northbound, according to analysis of data recorded during the landing.
"It's as if the crater were attracting us somehow," said JPL's Dr. Andrew Johnson, engineer for a system that estimated the spacecraft's horizontal motion during the landing.
The spacecraft bounced 26 times and rolled about 200 meters (about 220 yards) before coming to rest inside the crater, whose outcrop represents a bonanza for geologists on the mission.
JPL geologist Dr. Tim Parker was able to correlate a few features on the horizon above the crater rim with features identified by Mars orbiters, and JPL imaging scientist Dr. Justin Maki identified the spacecraft's jettisoned backshell and parachute in another Opportunity image showing the outlying plains.
As a clincher, a new image from Mars Global Surveyor's camera shows the Opportunity lander as a bright feature in the crater. A dark feature near the lander may be the rover.
"I won't know if it's really the rover until I take another picture after the rover moves," said Dr. Michael Malin of Malin Space Science Systems, San Diego. He is a member of the rovers' science team and principal investigator for the camera on Mars Global Surveyor.
Opportunity's crater is at 1.95 degrees south latitude and 354.47 degrees east longitude, the opposite side of the planet from Spirit's landing site at 14.57 degrees south latitude and 175.47 degrees east longitude.
The first outcrop rock Opportunity examined up close is finely-layered, buff-colored and in the process of being eroded by windblown sand.
"Embedded in it like blueberries in a muffin are these little spherical grains," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' scientific instruments. Microscopic images show the gray spheres in various stages of being released from the rock.
"This is wild looking stuff," Squyres said. "The rock is being eroded away and these spherical grains are dropping out.
"The spheres may have formed when molten rock was sprayed into the air by a volcano or a meteor impact. Or, they may be concretions, or accumulated material, formed by minerals coming out of solution as water diffused through rock,” he said.
The main task for both rovers in coming weeks and months is to explore the areas around their landing sites for evidence in rocks and soils about whether those areas ever had environments that were watery and possibly suitable for sustaining life.
JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University at http://athena.cornell.edu.
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