Western Gusev

Long before the MER landers were named or launched, the two orbiters at Mars were asked to examine landing sites. Both the Odyssey and Mars Global Surveyor spacecraft have been collecting landing site data for the past two years. The MGS and ODY data were used as part of the decision making process in the final selection of the two landing sites. The types of data collected by the two orbiters included not only images of the surface but also thermal data about the surface composition, atmospheric data about the climate at each location, and the tracking of major dust storms in the region prior to landing. The presence of, and data collected by, the MGS and ODY orbiters have proven invaluable in MER mission planning.
This image shows some of the far-western areas of Gusev crater, and was captured on 27 June 2003, while Spirit was en-route to Mars.