Sand Trap
Image by NASA/JPL

Opportunity spent all of May stuck in a foot-tall dune of windblown dust and sand. By the time it broke free in early June, it had spun its wheels enough to have rolled 629 feet (191 meters) on firm ground—and had advanced only three feet (one meter). The first job for an un-stuck Opportunity: helping the team understand "how this ripple differs from dozens Opportunity easily crossed," according to project manager Jim Erickson.