[meteorite-list] Crystal-Rich Rock 'Mojave' is Next Mars Drill Target

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4443

Crystal-Rich Rock 'Mojave' is Next Mars Drill Target
Jet Propulsion Laboratory
January 14, 2015

A rock target where NASA's Curiosity Mars rover is using its sample-collection 
drill this week may have a salty story to tell.

This target, called "Mojave," displays copious slender features, slightly 
smaller than grains of rice, that appear to be mineral crystals. A chance 
to learn their composition prompted the Curiosity science team to choose 
Mojave as the next rock-drilling target for the 29-month-old mission investigating 
Mars' Gale Crater. The features might be a salt mineral left behind when 
lakewater evaporated.

This week, Curiosity is beginning a "mini-drill" test to assess the rock's 
suitability for deeper drilling, which collects a sample for onboard laboratory 
analysis.

A weeklong pause in science operations to install a new version of rover 
flight software is scheduled to begin early next week, possibly before 
completion of the drilling and sample delivery. This is the fourth new 
version of the onboard software since the rover's August 2012 landing.

The Mojave drilling begins Curiosity's third round of investigating the 
basal layer of Mount Sharp exposed at an area called "Pahrump Hills." 
In the first round, the rover drove about 360 feet (110 meters) and scouted 
sites ranging about 30 feet (9 meters) in elevation. Then it followed 
a similar path, investigating selected sites in more detail. That second 
pass included inspection of Mojave in November 2014 with the dust-removal 
brush, close-up camera and Alpha Particle X-Ray Spectrometer on the rover's 
arm. The results put Mojave at the head of the list of targets for the 
rover's most intensive inspection, using laboratory instruments that ingest 
powdered rock collected by the drill.

"The crystal shapes are apparent in the earlier images of Mojave, but 
we don't know what they represent," said Curiosity Project Scientist Ashwin 
Vasavada at NASA's Jet Propulsion Laboratory, Pasadena, California. "We're 
hoping that mineral identifications we get from the rover's laboratory 
will shed more light than we got from just the images and bulk chemistry."

Curiosity's Chemistry and Mineralogy instrument, or CheMin, can identify 
specific minerals in rock powder from a drilled sample. Analysis of the 
drill hole and drill tailings may also reveal whether the crystals are 
only at the surface, like a salty crust, or are also deeper in the rock.

"There could be a fairly involved story here," Vasavada said. "Are they 
salt crystals left from a drying lake? Or are they more pervasive through 
the rock, formed by fluids moving through the rock? In either case, a 
later fluid may have removed or replaced the original minerals with something 
else."

Curiosity's work at Pahrump Hills may include drilling one or more additional 
rocks before heading to higher layers of Mount Sharp.

Next week's planned software revision, like the mission's earlier ones, 
adds protections against vulnerabilities identified in rover testbed activities 
on Earth. It also adds improvements to make planning drives more efficient.

"The files have already been uplinked and are sitting in the rover's file 
system to be ready for the installation," said JPL's Danny Lam, the deputy 
engineering operations chief leading the upgrade process.

One change in the new software is to enable use of the rover's gyroscope-containing 
"inertial measurement unit" at the same time as the rover's drill, for 
better capability to sense slippage of the rover during a drilling operation. 
Another is a set of improvements to the rover's ability to autonously 
identify and drive in good terrain.

NASA's Mars Science Laboratory Project is using Curiosity to assess ancient 
habitable environments and major changes in Martian environmental conditions. 
JPL, a division of the California Institute of Technology in Pasadena, 
built the rover and manages the project for NASA's Science Mission Directorate 
in Washington.

For more information about Curiosity, visit:

http://www.nasa.gov/msl

and

http://mars.jpl.nasa.gov/msl/

You can follow the mission on Facebook and Twitter at:

http://www.facebook.com/marscuriosity

and

http://www.twitter.com/marscuriosity


Media Contact

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

2015-017