This view from the Mars Exploration Rover Opportunity's rear hazard-avoidance camera looks back up toward the "Endurance Crater" rim from the deepest point of a dip into the crater during the rover's 134th martian day, or sol, on June 9, 2004. In this image, the rover is pitched forward about 18 degrees and the rear wheels are about 30 centimeters (about 12 inches) below the rim of the crater. The success of this engineering test of the slope and rock surface led rover planners to make plans to proceed into the crater for further scientific investigation.