[meteorite-list] Mars Rock Touched By NASA Curiosity Rover Offers Surprises

[Ron Baalke]

Oct. 11, 2012

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

Guy Webster / D.C. Agle 
Jet Propulsion Laboratory, Pasadena, Calif. 
818-354-5011 
guy.webster at jpl.nasa.gov 
agle at jpl.nasa.gov 


RELEASE: 12-359

MARS ROCK TOUCHED BY NASA CURIOSITY ROVER OFFERS SURPRISES

PASADENA, Calif. -- The first Martian rock NASA's Curiosity rover has 
reached out to touch presents a more varied composition than expected 
from previous missions. The rock also resembles some unusual rocks 
from Earth's interior. 

The rover team used two instruments on Curiosity to study the chemical 
makeup of the football-size rock called "Jake Matijevic." The results 
support some surprising recent measurements and provide an example of 
why identifying rocks' composition is such a major emphasis of the 
mission. Rock compositions tell stories about unseen environments and 
planetary processes. 

"This rock is a close match in chemical composition to an unusual but 
well-known type of igneous rock found in many volcanic provinces on 
Earth," said Edward Stolper of the California Institute of Technology 
in Pasadena, Calif., who is a Curiosity co-investigator. "With only 
one Martian rock of this type, it is difficult to know whether the 
same processes were involved, but it is a reasonable place to start 
thinking about its origin." 

On Earth, rocks with composition like the Jake rock typically come 
from processes in the planet's mantle beneath the crust, from 
crystallization of relatively water-rich magma at elevated pressure. 

Jake was the first rock analyzed by the rover's arm-mounted Alpha 
Particle X-Ray Spectrometer (APXS) instrument and about the thirtieth 
rock examined by the Chemistry and Camera (ChemCam) instrument. Two 
penny-size spots on Jake were analyzed Sept. 22 by the rover's 
improved and faster version of earlier APXS devices on all previous 
Mars rovers, which have examined hundreds of rocks. That information 
has provided scientists a library of comparisons for what Curiosity 
sees. 

"Jake is kind of an odd Martian rock," said APXS Principal 
Investigator Ralf Gellert of the University of Guelph in Ontario, 
Canada. "It's high in elements consistent with the mineral feldspar, 
and low in magnesium and iron." 

ChemCam found unique compositions at each of 14 target points on the 
rock, hitting different mineral grains within it. 

"ChemCam had been seeing compositions suggestive of feldspar since 
August, and we're getting closer to confirming that now with APXS 
data, although there are additional tests to be done," said ChemCam 
Principal Investigator Roger Wiens of Los Alamos National Laboratory 
in New Mexico. 

Examination of Jake included the first comparison on Mars between APXS 
results and results from checking the same rock with ChemCam, which 
shoots laser pulses from the top of the rover's mast. 

The wealth of information from the two instruments checking chemical 
elements in the same rock is just a preview. Curiosity also carries 
analytical laboratories inside the rover to provide other composition 
information about powder samples from rocks and soil. The mission is 
progressing toward getting the first soil sample into those 
analytical instruments during a "sol" or Martian day. 

"Yestersol, we used Curiosity's first perfectly scooped sample for 
cleaning the interior surfaces of our 150-micron sample-processing 
chambers. It's our version of a Martian carwash," said Chris 
Roumeliotis, lead turret rover planner at NASA's Jet Propulsion 
Laboratory (JPL) in Pasadena, Calif. 

Before proceeding, the team carefully studied the material for 
scooping at a sandy patch called "Rocknest," where Curiosity is 
spending about three weeks. 

"That first sample was perfect, just the right particle-size 
distribution," said JPL's Luther Beegle, Curiosity sampling-system 
scientist. "We had a lot of steps to be sure it was safe to go 
through with the scooping and cleaning." 

Following the work at Rocknest, the rover team plans to drive 
Curiosity about 100 yards eastward and select a rock in that area as 
the first target for using the drill. 

During a two-year prime mission, researchers will use Curiosity's 10 
instruments to assess whether the study area ever has offered 
environmental conditions favorable for microbial life. JPL, a 
division of Caltech, manages the project and built Curiosity. For 
more about the Mars Science Laboratory Curiosity rover mission, 
visit: 

http://www.nasa.gov/msl 

You can follow the mission on Facebook and Twitter at: 

http://www.facebook.com/marscuriosity 

and 

http://www.twitter.com/marscuriosity 

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