NASA Mars bedrock bears hopes for insight

Engineers think the Opportunity rover is turning on its heater unnecessarily.
PASADENA, Calif. (AP) -- Scientists were looking forward to doing further analysis on the half-inch thick layers evident in images of martian rocks sent back by the NASA rover Opportunity.
Each layer represents an event in the geologic history of the Red Planet and could indicate whether the outcropping could have been formed by water.
The horizontally striped and fractured slabs of bedrock rim a portion of the shallow depression and lie just a short drive from where the six-wheeled robot sits atop its lander.
"Look at the wonderful layer-cake structure in there," Steve Squyres, the mission's main scientist, said Tuesday. "It's going to be fascinating beyond words to get up close and personal with this thing."
Opportunity should be able to reconstruct the geologic events that created the fine layers with its complement of cameras and scientific instruments.
Theory on formation
Scientists think the layers were laid down over a relatively brief period -- anywhere from a single day to several millennia -- but billions of years ago. They piled up either as ash spewed by successive volcanic eruptions or as sediments borne by wind or water.
"By stringing them together, we develop a sense of history," said Andrew Knoll of Harvard University, a member of the mission science team.
Some scientists think the 18-inch-high band of layered rocks is cross-bedded in part, suggesting a sedimentary origin that would require the presence of water.
If so, the rocks could provide the tangible evidence NASA seeks that Mars once was a wetter place capable of sustaining life. Images taken from orbit already suggest vast amounts of water once flowed across the surface of the planet.
Condition of rover
The Opportunity rover was in good shape after its weekend landing but had developed a small, 15-watt power loss that worried NASA. It also began unfolding and successfully deployed and tested its high-gain antenna, used to communicate directly with Earth.
Engineers think a heater in the shoulder of its robotic arm has been turning on unnecessarily when temperatures drop. Typically, the heater is needed only when the arm is in use, mission manager Jim Erickson said.
"We don't normally want it on. Right now we believe it's going to be continuously on whenever it's cold enough," Erickson said.
Engineers continued to monitor the situation, unsure if it could harm the rover.
"We're very paranoid people," Erickson said.
Opportunity's twin, Spirit, continued to convalesce, 6,600 miles around the planet. Engineers received additional data from the ailing rover that is furthering their quest to understand computer problems that last week brought its science work to a grinding halt.
Engineers think Spirit does not have sufficient random-access memory to manage all the files in its flash memory, which is similar to the memory that digital cameras use to store photographs.