January 27, 2004
Scientists
Thrilled to See Layers in Mars Rocks
New pictures from NASA's Mars Exploration
Rover Opportunity reveal thin layers in rocks just a stone's
throw from the lander platform where the rover temporarily sits.
Layered Rocks by Opportunity
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for larger image
Courtesy NASA/JPL/Cornell
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. If the rocks are sedimentary, water is a more
likely source than wind, according to Dr. Andrew Knoll of Harvard
University, Cambridge, a member of the science team.
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. Examination 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.
"We're about to embark on what could
be the coolest geological field trip in history," Dr. Steve
Sqyures, principal investigator for the rovers' science payload,
said.
Opportunity successfully used its high-gain
antenna for the first time yesterday. The rover is losing some
if 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 fixing
the problems with the other Mars rover, 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,
according to JPL's Jennifer Trosper, mission manager.
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.
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