[meteorite-list] One Mars Rover Sees a Distant Goal; The Other Takes a New Route

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 20 Mar 2009 17:07:44 -0700 (PDT)
Message-ID: <200903210007.RAA29539_at_zagami.jpl.nasa.gov>


One Mars Rover Sees a Distant Goal; The Other Takes a New Route
Jet Propulsion Laboratory
March 18, 2009

PASADENA, Calif. -- On a plain that stretches for miles in every
direction, the panoramic camera on NASA's Mars rover Opportunity has
caught a first glimpse on the horizon of the uplifted rim of the big
crater that has been Opportunity's long-term destination for six months.

Opportunity's twin, Spirit, also has a challenging destination, and last
week switched to a different route for making progress.

Endeavour Crater, 22 kilometers (14 miles) in diameter, is still 12
kilometers (7 miles) away from Opportunity as the crow flies, and at
least 30 percent farther away on routes mapped for evading hazards on
the plain. Opportunity has already driven about 3.2 kilometers (2 miles)
since it climbed out of Victoria Crater last August after two years of
studying Victoria, which is less than one-twentieth the size of Endeavour.

"It's exciting to see our destination, even if we can't be certain
whether we'll ever get all the way there," said John Callas of NASA's
Jet Propulsion Laboratory, Pasadena, Calif., project manager for the
twin Mars rovers, Opportunity and Spirit. "At the pace we've made since
leaving Victoria, the rest of the trek will take more than a Martian
year." A Martian year lasts about 23 months.

The image with portions of Endeavour's rim faintly visible can be seen
online at http://www.nasa.gov/mission_pages/mer/images/mer20090318.html .

Steve Squyres of Cornell University, Ithaca, N.Y., principal
investigator for the rovers' science instruments, said, "We can now see
our landfall on the horizon. It's far away, but we can anticipate seeing
it gradually look larger and larger as we get closer to Endeavour. We
had a similar experience during the early months of the mission watching
the Columbia Hills get bigger in the images from Spirit as Spirit drove
toward them."

Both rovers landed on Mars in January 2004 to begin missions designed to
last for three months. Both are still active after more than five years.

For the next several days, the rover team plans to have Opportunity use
the tools on its robotic arm to examine soil and rock at an outcrop
along the route the rover is taking toward Endeavour.

"We're stopping to taste the terrain at intervals along our route so
that we can watch for trends in the composition of the soil and
bedrock," Squyres said. "It's part of systematic exploration."

The pause for using the tools on the arm also provides two other
benefits. Opportunity's right-front wheel has been drawing more electric
current than usual, an indication of friction within the wheel. Resting
the wheel for a few days is one strategy that has in the past helped
reduce the amount of current drawn by the motor. Also, on March 7, the
rover did not complete the backwards-driving portion of its commanded
drive due to unanticipated interaction between the day's driving
commands and onboard testing of capabilities for a future drive. The
team is analyzing that interaction before it will resume use of
Opportunity's autonomous-driving capabilities.

Meanwhile, on March 10, the rover team decided to end efforts to drive
Spirit around the northeastern corner of a low plateau called "Home
Plate" in the inner basin of the Columbia Hills, on the other side of
Mars from Opportunity. Spirit has had the use of only five wheels since
its right-front wheel stopped working in 2006. Consequently, it usually
drives backwards, dragging that wheel, so it can no longer climb steep

Callas said, "After several attempts to drive up-slope in loose material
to get around the northeast corner of Home Plate, the team judged that
route to be impassable."

The new route to get toward science targets south of Home Plate is to go
around the west side of the plateau.

Squyres said, "The western route is by no means a slam dunk. It is
unexplored territory. There are no rover tracks on that side of Home
Plate like there are on the eastern side. But that also makes it an
appealing place to explore. Every time we've gone someplace new with
Spirit since we got into the hills, we've found surprises."

JPL, a division of the California Institute of Technology, Pasadena,
manages the Mars Exploration Rovers for the NASA Science Mission
Directorate, Washington. More information about the rovers is at
http://www.nasa.gov/rovers .

Media Contact: Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov

Received on Fri 20 Mar 2009 08:07:44 PM PDT

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