2d Mars rover sends photos as repairs to twin continue

PASADENA, Calif. -- NASA released yesterday the first color photographs taken by the rover Opportunity of layers of Martian rock that could have been formed by water.

"Some of the detail you can see in here is pretty phenomenal," said Jim Bell, lead scientist for the panoramic camera on the rover, while displaying several of the photos at a news conference at the Jet Propulsion Laboratory.

The horizontally striped and fractured slabs of bedrock are just a short drive from where the six-wheeled robot sits atop its lander. Each layer represents an event in the geologic history of the Red Planet and could indicate whether water was present at one time.

With its scientific instruments, Opportunity should be able to reconstruct the geological events that created the fine layers.

Bell said scientists have no direct information on the composition of the rocks. But the photos will help them decide where to send the rover. Among other things, the images could show lava flows or sediment deposits that could have been borne by wind or water, he said.

Scientists believe 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 from wind or water.

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.

Scientists also reported progress in unfolding the rover from its landing position and preparing it to leave the lander.

The rover could roll off its lander early next week after its rear wheels are lowered and other functions are performed. On the other side of Mars, Opportunity's twin, Spirit, continued to recover. Engineers received data from the ailing rover that is furthering their quest to understand computer problems that halted its science work last week.

"We are working to get complete control of the vehicle but still aren't quite there yet," said Jennifer Trosper, a mission manager.

Engineers believe Spirit does not have sufficient random-access memory to manage all the files in its flash memory. To prevent similar problems on Opportunity, engineers deleted recently created but unneeded computer files from its flash memory, which is similar to the memory that digital cameras use to store photographs.