Ecstatic scientists used the Mars rover's powerful camera Friday to take the first close-up images ever made of the Martian surface and immediately confronted a new mystery over what they saw. The images that Spirit sent down from its Martian parking spot, a few feet in front of its landing pad, was a flat patch of fine- and coarse-grained sand -- much of it stuck together in clumps that scientists conceded they did not yet understand. The pictures, taken in stereoscopic clarity by Spirit's Microscopic Imager, appeared for all the world like a patch of coarse-grained sandpaper viewed through a modest magnifying glass. But to Kenneth Herkenhoff, an astrogeologist with the U.S. Geological Survey and a member of Spirit's science team, the images might show some kind of electrostatic force operating on the fine-grained materials, or they could possibly indicate that the roughened clumps of sand were formed billions of years ago by salts that bound the grains together when the chemicals were wet.

Countless other theories are being proposed by the mysterious cohesiveness of the sandy stuff, said Rob Sullivan of Cornell, another member of the science team. In coming days, Sullivan and his colleagues plan to spin each of the rover's six driving wheels separately in order to dig trenches in the sand, and then focus the Microscopic Imager on the soil a few inches beneath the surface.


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