Scientists Thrilled To See Layers in Mars Rocks Near Opportunity(January 27, 2004)
Geologists said that the layers -- some no thicker than a finger -- indicate the rocks likely originated either from sediments carried by water or wind, or from falling volcanic ash. "We should be able to distinguish between those two hypotheses," said Dr. Andrew Knoll of Harvard University, Cambridge, a member of the science team for Opportunity and its twin, Spirit. If the rocks are sedimentary, water is a more likely source than wind, he said.
The prime goal for both rovers is to explore their landing areas for clues in the rocks and soil about whether those areas ever had watery environments that could possibly have sustained life.
Controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., plan to tell Opportunity tonight to start standing up from the crouched and folded posture in which it traveled to Mars.
"We're going to lift the entire rover, then the front wheels will be turned out," said Mission Manager Jim Erickson of JPL. Several more days of activities are still ahead before the rover will be ready to drive off the lander.
"We're about to embark on what could be the coolest geological field trip in history," said Dr. Steve Sqyures of Cornell University, Ithaca, N.Y., principal investigator for the rovers' science payload.
The layered rocks are in a bedrock outcrop about 30 to 45 centimeters (12 to 18 inches) tall, and only about eight meters (26 feet) away from where Opportunity came to rest after bouncing to a landing three days ago. Examinatio n of their texture and composition with the cameras and spectrometers on the rover may soon reveal whether they are sedimentary, Knoll predicted.
Scientists also hope to determine the relationship between those light-colored rocks and the dark soil that covers most of the surrounding terrain. The soil may contain the mineral hematite, which was identified from orbit and motivated the choice of Opportunity's landing area, Squyres said.
Opportunity successfully used its high-gain antenna for the first time yesterday. The rover is losing some of its battery charge each night, apparently due to an electric heater at the shoulder joint of the rover's robotic arm. A thermostat turns on the heater whenever the air temperature falls to levels that Opportunity is experiencing every night. The heater is not really needed when the arm is not in use, but ground control has not been able to activate a switch designed to override the thermostat, Erickson said. Mission engineers are working to confirm the diagnosis, determine the ramifications of the power drain, and propose workarounds or fixes.
Meanwhile, engineers working on Spirit have determined that the high-gain antenna on that rover is likely in working order despite earlier indications of a possible problem. They are continuing to take information out of Spirit's flash memory. Results from a testbed simulator of the rover's electronics supported the diagnosis of a problem with management of the flash memory, reported JPL's Jennifer Trosper, mission manager.