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

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)
February 5, 2004
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:

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


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