This image taken by the microscopic imager on the Mars Exploration Rover Spirit shows a close-up look at the rock dubbed "Humphrey." The image was taken after the rover drilled into the rock with its rock abrasion tool, exposing fresh rock underneath. Scientists examined "Humphrey" for clues to its past with scientific instruments on the rover's robotic arm. This image was taken on the 60th martian day, or sol, of Spirit's mission. The rover is on its way to a large crater nicknamed "Bonneville."
Image credit: NASA/JPL/Cornell/USGS