[meteorite-list] Opportunity Mars Rover Goes Six-Wheeling up a Ridge

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=5580

Opportunity Mars Rover Goes Six-Wheeling up a Ridge
Jet Propulsion Laboratory
February 25, 2016

NASA's senior Mars rover, Opportunity, is working adeptly in some of the 
most challenging terrain of the vehicle's 12 years on Mars, on a slope 
of about 30 degrees.

Researchers are using Opportunity this month to examine rocks that may 
have been chemically altered by water billions of years ago. The mission's 
current targets of investigation are from ruddy-tinted swaths the researchers 
call "red zones," in contrast to tan bedrock around these zones.

The targets lie on "Knudsen Ridge," atop the southern flank of "Marathon 
Valley," which slices through the western rim of Endeavour Crater.

A panorama of Knudsen Ridge is online at:

http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20319

"We're hoping to take advantage of the steep topography that Mars provides 
us at Knudsen Ridge to get to a better example of the red zone material," 
said Steve Squyres of Cornell University, Ithaca, New York, principal 
investigator for the mission.

The red zone material crumbles easily. At locations in Marathon Valley 
where Opportunity already got a close look at it, the reddish bits are 
blended with other loose material accumulating in low locations. A purer 
exposure of the red zone material, such as some apparent on the ridge, 
would provide a better target for the Alpha Particle X-ray Spectrometer 
on Opportunity's arm, which reveals the chemical composition of rocks 
and soil.

Opportunity began climbing Knudsen Ridge in late January with two drives 
totaling 31 feet (9.4 meters). The wheels slipped less than 20 percent 
up slopes as steep as 30 degrees, the steepest the rover has driven since 
its first year on Mars in 2004. The slip is calculated by comparing the 
distance the rotating wheels would have covered if there were no slippage 
to the distance actually covered in the drive, based on "visual odometry" 
imaging of the terrain the rover passes as it drives.

"Opportunity showed us how sure-footed she still is," said Mars Exploration 
Rover Project Manager John Callas at NASA's Jet Propulsion Laboratory, 
Pasadena, California. "The wheel slip has been much less than we expected 
on such steep slopes."

The rover made additional progress toward targets of red-zone material 
on Knudsen Ridge with a drive on Feb. 18.

Knudsen Ridge forms a dramatic cap overlooking the 14-mile-wide (22-kilometer-wide) 
Endeavour Crater. Its informal naming honors the memory of Danish astrophysicist 
and planetary scientist Jens Martin Knudsen (1930-2005), a founding member 
of the science team for Opportunity and the twin rover Spirit. "This ridge 
is so spectacular, it seemed like an appropriate place to name for Jens 
Martin," Squyres said.

Marathon Valley became a high-priority destination for the Opportunity 
mission when mineral-mapping observations by the Compact Reconnaissance 
Imaging Spectrometer for Mars (CRISM), aboard NASA's Mars Reconnaissance 
Orbiter, located clay minerals (a type of phyllosilicate) in this valley. 
Clay minerals often form in the presence of water, which is why this is 
such a promising area of exploration. Opportunity found evidence of ancient 
water shortly after landing, but there were signs that the water would 
have been more highly acidic. The investigation in Marathon Valley could 
add understanding about the ancient environmental context for the presence 
of non-acidic water, a factor favorable for microbial life, if any has 
ever existed on Mars.

"The locations of red zones in Marathon Valley correlate closely with 
the phyllosilicate signature we see from orbit," Squyres said. "That alone 
is not a smoking gun. We want to determine what it is about their chemistry 
that sets them apart and what it could have to do with water."

To test the idea that water affected the red zone material, the experiment 
underway aims to compare the chemistry of that material to the chemistry 
of the surrounding tan bedrock, which could represent an unaltered baseline. 
Opportunity used its diamond-toothed rock abrasion tool last month to 
scrape the crust off a tan bedrock target for an examination of the chemistry 
inside the rock.

The team is accomplishing productive science with Opportunity while avoiding 
use of the rover's flash memory, which was linked to several unplanned 
computer reboots last year. The only data being received from Opportunity 
is what can be transmitted each day before the solar-powered rover shuts 
down for energy-conserving overnight "sleep."

For more information about Opportunity, visit:

http://www.nasa.gov/rovers

http://marsrovers.jpl.nasa.gov


Media Contact

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

Dwayne Brown / Laurie Cantillo
NASA Headquarters, Washington
202-358-1726 / 202-358-1077
dwayne.c.brown at nasa.gov / laura.l.cantillo at nasa.gov 

2016-050