Mars Exploration Rover Mission Status
November 11, 2004
Operators of NASA's Mars Exploration Rover Opportunity have
determined that a proposed route eastward out of "Endurance
Crater" is not passable, so the rover will backtrack to leave
the crater by a southward route, perhaps by retracing its entry
path.
"We've done a careful analysis of the ground in front of
Opportunity and decided to turn around," said Jim Erickson,
rover project manager at NASA's Jet Propulsion Laboratory,
Pasadena, Calif. "To the right, the slope is too steep -- more
than 30 degrees. To the left, there are sandy areas we can't be
sure we could get across."
Before turning around, Opportunity will spend a few days
examining the rock layers in scarp about 10 meters (33 feet)
high, dubbed "Burns Cliff." From its location at the western
foot of the cliff, the rover will use its panoramic camera and
miniature thermal emission spectrometer to collect information
from which scientists hope to determine whether some of the
layers were deposited by wind, rather than by water. The rover
will not reach an area about 15 meters (50 feet) farther east
where two layers at different angles meet at the base of the
cliff.
"We have pushed the vehicle right to the edge of its
capabilities, and we've finally reached a spot where we may be
able to answer questions we've been asking about this site for
months," said Dr. Steve Squyres, rover principal investigator at
Cornell University, Ithaca, N.Y. "But after we're done here,
it'll be time to turn around. Going any farther could cut off
our line of retreat from the crater, and that's not something
anybody on the team wants to do."
Opportunity entered the stadium-size crater on June 8 at a site
called "Karatepe" along the crater's southern rim. Inside the
crater, it has found and examined multiple layers of rocks that
show evidence of a wet environment in the area's distant past.
Opportunity and its twin, Spirit, successfully completed their
primary three-month missions on Mars in April. NASA has extended
their missions twice, most recently on Oct. 1, because the
rovers have remained in good condition to continue exploring
Mars longer than anticipated.
Engineers have finished troubleshooting an indication of a
problem with steering brakes on Spirit. The brakes are designed
to keep the rover wheels from being bumped off course while
driving. Spirit has intermittently sent information in recent
weeks that the brakes on two wheels were not releasing properly
when the rover received commands to set a new course. Testing
and analysis indicate that the mechanism for detecting whether
the brakes are released is probably sending a false indication.
The rover team will disregard that signal and presume the brakes
have actually released properly when commanded to do so. This
anomaly has not been observed on the Opportunity rover.
"We're going back to using the full steering capabilities of
Spirit," Erickson said.
JPL, a division of the California Institute of Technology
in Pasadena, manages the Mars Exploration Rover project for
NASA's Science Mission Directorate, Washington, D.C.
Additional information about the project is available from
JPL at http://marsrovers.jpl.nasa.gov/ and from Cornell
University, Ithaca, N.Y., at http://athena.cornell.edu.
Guy Webster (818) 354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Don Savage (202) 358-1727
NASA Headquarters, Washington
2004-276