Spirit's Shadow Date: 02.22.2004 NASA's Mars Exploration Rover Spirit casts a shadow over the trench that the rover is examining with tools on its robotic arm. Spirit took this image with its front hazard-avoidance camera on Feb. 21, 2004, during the rover's 48th martian day, or sol. It dug the trench with its left front wheel the preceding sol. Plans call for Spirit to finish examining the trench on sol 50.