This image from the Mars Exploration Rover Spirit's rear hazard avoidance camera shows the rover's hind view of the lander platform, its nest for the past 12 sols, or martian days. The rover is approximately 1 meters (3 feet) in front of the airbag-cushioned lander, facing northwest. Note the tracks left in the martian soil by the rovers' wheels, all six of which have rolled off the lander. This is the first time the rover has touched martian soil. Credit: NASA/JPL