With the Phoenix lander busily working away on Mars and grabbing the recent headlines, we haven’t heard much from the other two robots on the Red Planet, the Mars Exploration Rovers, Spirit and Opportunity. Spirit has been hunkered down, trying to survive the harshest weeks of southern Martian winter. She’s waiting for the sun’s rays to get a little stronger before moving on, but has been taking images of her spot in the Home Plate area of Gusev Crater to create the panorama, shown here. Opportunity is now getting ready to head ’em up and move ’em out of Victoria Crater, where she’s been for nearly a year. So, what’s coming up for the two Energizer Bunny-like, long-lasting rovers?
“Both rovers show signs of aging, but they are both still capable of exciting exploration and scientific discovery,” said JPL’s John Callas, project manager for Spirit and Opportunity.
The team’s plan for future months is to drive Spirit south of Home Plate to an area where the rover last year found some bright, silica-rich soil. This could be possible evidence of effects of hot water.
Click here for an extra large version of Spirit’s panorama.
Opportunity will soon be on to new adventures.
“We’ve done everything we entered Victoria Crater to do and more,” said Bruce Banerdt, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Banerdt is project scientist for the two rovers. Opportunity is heading back out to the Red Planet’s surrounding plains and check out some loose cobbles, or rocks that it drove by nearly a year ago before descending into the large Victoria crater to examine exposed ancient rock layers. But now that survey is complete.
Some of the cobbles that the rover will look at are approximately fist-size and larger. They were thrown long distances from impacts on Mars surface, and are interesting in that they might provide information about Mars’ subsurface varying areas.
“Our experience tells us there’s lots of diversity among the cobbles,” said Scott McLennan of the State University of New York, Stony Brook. McLennan is a long-term planning leader for the rover science team. “We want to get a better characterization of them. A statistical sampling from examining more of them will be important for understanding the geology of the area.”
Opportunity entered Victoria Crater on Sept. 11, 2007, after a year of scouting from the rim. Once inside, the rover drove close to the base of a cliff called “Cape Verde,” part of the crater rim, to capture detailed images of a stack of layers 6 meters (20 feet) tall. The information Opportunity has returned about the layers in Victoria suggest the sediments were deposited by wind and then altered by groundwater.
“The patterns broadly resemble what we saw at the smaller craters Opportunity explored earlier,” McLennan said. “By looking deeper into the layering, we are looking farther back in time.” The crater stretches approximately 800 meters (half a mile) in diameter and is deeper than any other seen by Opportunity.
Engineers are programming Opportunity to climb out of the crater at the same place it entered. A spike in electric current drawn by the rover’s left front wheel last month quickly settled discussions about whether to keep trying to edge even closer to the base of Cape Verde on a steep slope. The spike resembled one seen on Spirit when that rover lost the use of its right front wheel in 2006. Opportunity’s six wheels are all still working after 10 times more use than they were designed to perform, but the team took the spike in current as a reminder that one could quit.
“If Opportunity were driving with only five wheels, like Spirit, it probably would never get out of Victoria Crater,” said JPL’s Bill Nelson, a rover mission manager. “We also know from experience with Spirit that if Opportunity were to lose the use of a wheel after it is out on the level ground, mobility should not be a problem.”
Opportunity now drives with its robotic arm out of the stowed position. A shoulder motor has degraded over the years to the point where the rover team chose not to risk having it stop working while the arm is stowed on a hook. If the motor were to stop working with the arm unstowed, the arm would remain usable.
Source: JPL Press Release