This mosaic was produced from pictures taken with the microscopic imager on NASA's Mars Exploration Rover Opportunity on sol 154 (June 29, 2004). It shows one of a series of holes ground by the rover's rock abrasion tool in "Endurance Crater." This time Opportunity stretched its arm, or instrument deployment device, out to a target called "Kettlestone." Grinding for just over two hours on sol 153, Opportunity successfully created a hole 4.5 centimeters (1.8 inches) in diameter and 4.17 millimeters (.16 inches) deep.