This picture from the microscopic imager on NASA's Mars Exploration Rover Opportunity is a mosaic of a target called "Gagarin" on a rock referred to as "Yuri." Opportunity brushed the target with the rock abrasion tool during the rover's 401st martian day, or sol, (March 10, 2005) and then took the individual images that are combined into this mosaic. The rock abrasion tool ground into the same target on the following sol.
The circle from which the tool's wire brush has scoured dust off the rock surface is about 5 centimeters (2 inches) in diameter.
This rock is near the rim of "Vostok" crater. Yuri Gagarin was the first man to orbit Earth. The Russian cosmonaut's spacecraft was named Vostok NASA/JPL/Cornell/USGS1.