February 5, 2004

Donald Savage 
Headquarters, Washington 
(Phone: 202/358-1547)

Guy Webster 
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
RELEASE: 04-054

NASA'S TWIN ROVERS TAKE SPIRITED OPPORTUNITY TO EXPLORE

NASA's Opportunity Mars rover examined its first patch of soil in the 
small crater where it landed and found strikingly spherical pebbles. 

"There are features in this soil unlike anything ever seen on Mars 
before," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., 
principal investigator for the science instruments on the two Mars 
Exploration Rovers.

For better understanding of the soil, mission controllers at NASA's 
Jet Propulsion Laboratory, Pasadena, Calif., plan to use 
Opportunity's wheels to scoop a trench to expose deeper material. 
Tomorrow, one front wheel will rotate to dig the hole, while the 
other five wheels hold the rover stationary. 

The spherical particles appear in new pictures from Opportunity's 
microscopic imager camera. Other particles in the image have jagged 
shapes. "The variety of shapes and colors indicates we're having 
particles brought in from a variety of sources," said Dr. Ken 
Herkenhoff of the U.S. Geological Survey's Astrogeology Team, 
Flagstaff, Ariz.

The shapes don't reveal the particles' origin with certainty. "A 
number of straightforward geological processes can yield round 
shapes," said Dr. Hap McSween, a rover science team member from the 
University of Tennessee, Knoxville. "They include accretion under 
water, but apparent pores in the particles make alternative 
possibilities of meteor impacts or volcanic eruptions more likely 
origins," he said.

A mineral map of Opportunity's surroundings, the first from the 
surface of another planet, shows concentrations of hematite vary in 
different parts of the crater. The soil patch in the images is in an 
area low in hematite. The map shows higher hematite concentrations 
inside the crater in a layer above an outcrop of bedrock and on the 
slope just under the outcrop. 

Hematite usually forms in association with liquid water, so it holds 
special interest for the scientists trying to determine whether the 
rover landing sites ever had watery environments. The map uses data 
from Opportunity's miniature thermal emission spectrometer, which 
identifies rock types from a distance. 

"We're seeing little bits and pieces of this mystery, but we haven't 
pieced all the clues together yet," Squyres said. 

Opportunity's Moessbauer spectrometer, an instrument on the rover's 
robotic arm designed to identify the types of iron-bearing minerals, 
found a strong signal in the soil patch for olivine. Olivine is a 
common ingredient in volcanic rocks. A few days of analysis may be 
needed to discern whether any fainter signals are from hematite, said 
Dr. Franz Renz, science team member from the University of Mainz, 
Germany. To get a better look at the hematite closer to the outcrop, 
Opportunity will go there. It will begin by driving about three 
meters (10 feet), taking it about halfway to the outcrop. 

Opportunity's twin, Spirit, is reformatting its flash memory as a 
preventive measure. "We spent the last four days testing this," Adler 
said. "It's not an operation we do lightly. We've got to be sure it 
works right." Controllers plan to tell Spirit to brush dust off of a 
rock and examine the cleaned surface, when it returns to exploration 
operations.

JPL, a division of the California Institute of Technology in Pasadena, 
manages the Mars Exploration Rover project for NASA's Office of Space 
Science, Washington. Images and additional information about the 
project are available on the Internet at: 

http://marsrovers.jpl.nasa.gov 

For information about NASA and the Mars mission on the Internet, 
visit: 

http://www.nasa.gov 

	
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