[meteorite-list] NASA's Mars Rover Opportunity Climbing Out of Victoria Crater

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 26 Aug 2008 13:31:38 -0700 (PDT)
Message-ID: <200808262031.NAA29813_at_zagami.jpl.nasa.gov>

Aug. 26, 2008

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown at nasa.gov

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

RELEASE: 08-216

NASA'S MARS ROVER OPPORTUNITY CLIMBING OUT OF VICTORIA CRATER

PASADENA, Calif. -- NASA's Mars Exploration rover Opportunity is
heading back out to the Red Planet's surrounding plains nearly a year
after descending into a large Martian crater to examine exposed
ancient rock layers.

"We've done everything we entered Victoria Crater to do and more,"
said Bruce Banerdt, of NASA's Jet Propulsion Laboratory in Pasadena,
Calif. Banerdt is project scientist for Opportunity and its rover
twin, Spirit.

Having completed its job in the crater, Opportunity is now preparing
to inspect loose cobbles on the plains. Some of these rocks,
approximately fist-size and larger, were thrown long distances when
objects hitting Mars blasted craters deeper than Victoria into the
Red Planet. Opportunity has driven past scores of cobbles but
examined only a few.

"Our experience tells us there's lots of diversity among the cobbles,"
said Scott McLennan of the State University of New York, Stony Brook.
McLennan is a long-term planning leader for the rover science team.
"We want to get a better characterization of them. A statistical
sampling from examining more of them will be important for
understanding the geology of the area."

Opportunity entered Victoria Crater on Sept. 11, 2007, after a year of
scouting from the rim. Once a drivable inner slope was identified,
the rover used contact instruments on its robotic arm to inspect the
composition and textures of accessible layers.

The rover then drove close to the base of a cliff called "Cape Verde,"
part of the crater rim, to capture detailed images of a stack of
layers 20 feet tall. The information Opportunity has returned about
the layers in Victoria suggest the sediments were deposited by wind
and then altered by groundwater.

"The patterns broadly resemble what we saw at the smaller craters
Opportunity explored earlier," McLennan said. "By looking deeper into
the layering, we are looking farther back in time." The crater
stretches approximately a half mile in diameter and is deeper than
any other seen by Opportunity.

Engineers are programming Opportunity to climb out of the crater at
the same place it entered. A spike in electric current drawn by the
rover's left front wheel last month quickly settled discussions about
whether to keep trying to edge even closer to the base of Cape Verde
on a steep slope. The spike resembled one seen on Spirit when that
rover lost the use of its right front wheel in 2006. Opportunity's
six wheels are all still working after 10 times more use than they
were designed to perform, but the team took the spike in current as a
reminder that one could quit.

"If Opportunity were driving with only five wheels, like Spirit, it
probably would never get out of Victoria Crater," said JPL's Bill
Nelson, a rover mission manager. "We also know from experience with
Spirit that if Opportunity were to lose the use of a wheel after it
is out on the level ground, mobility should not be a problem."

Opportunity now drives with its robotic arm out of the stowed
position. A shoulder motor has degraded over the years to the point
where the rover team chose not to risk having it stop working while
the arm is stowed on a hook. If the motor were to stop working with
the arm unstowed, the arm would remain usable.

Spirit has resumed observations after surviving the harshest weeks of
southern Martian winter. The rover won't move from its winter haven
until the amount of solar energy available to it increases a few
months from now. The rover has completed half of a full-circle color
panorama from its sun-facing location on the north edge of a low
plateau called "Home Plate."

"Both rovers show signs of aging, but they are both still capable of
exciting exploration and scientific discovery," said JPL's John
Callas, project manager for Spirit and Opportunity.

The team's plan for future months is to drive Spirit south of Home
Plate to an area where the rover last year found some bright,
silica-rich soil. This could be possible evidence of effects of hot
water.

For images and information about NASA's Opportunity and Spirit Mars
rovers, visit:

http://www.nasa.gov/rovers

        
-end-
Received on Tue 26 Aug 2008 04:31:38 PM PDT