A sampling of Martian soils

Previous NASA Mars missions, including the Viking, Pathfinder, and Mars Exploration Rover, have studied Martian soils, and now Curiosity has used its X-ray spectroscopy. Similar soil types have been observed at all landing sites, as well as during the overland travels of both Mars Exploration Rovers.

The Mars Exploration Rover Spirit's landing region in Gusev Crater is seen in both pictures at top; Viking's landing site is shown at lower left; and a closeup of Curiosity's Gale Crater soil target, called "Portage," is at lower right.

In Gusev Crater, several white subsurface deposits were excavated with Spirit's wheels and found to be either silica-rich or hydrated ferric sulfates.