The soil results have yielded "an unprecedented look at the chemical diversity in the area that is representative of the rest of the planet," said Michael Meyer, the mission's program scientist, in a briefing at the annual fall meeting of the American Geophysical Union, currently underway in San Francisco.
The results "form a solid baseline for our continued exploration," he says.
During its six-week stay at a site named Rocknest, the rover sampled soils from a mini dune about 5 inches high dubbed Windrift. The rover scooped five samples in all. The initial samples were used to clean the interior of the sample-delivery system of any contaminants that hitched a ride from Earth. The fifth sample served as the fodder for the rover's internal chemistry labs.
Below the dune's surface the sands were fine-grained compared with the surface layer – somewhere between grains of sugar and flour in size. The large, salt-sized grains on the dune's surface, which included tiny glass nodules, were coated in the red dust characteristic of Mars, explains Ken Eddget, the lead scientist for a camera on the rover’s robotic arm that fills the role of a geologist's magnifying glass.
Water vapor, carbon dioxide, molecular oxygen, and sulfur dioxide were among the most prominent gases generated by the three instruments that comprise the rover's Sample Analysis at Mars (SAM) component, notes Paul Mahaffy, a researcher at NASA's Goddard Space Flight Center in Greenbelt, Md., and SAM's lead scientist.