NASA Mars rover Curiosity has driven out of the ellipse, approximately 4 miles wide and 12 miles long (7 kilometers by 20 kilometers), that was mapped as safe terrain for its 2012 landing inside Gale Crater.

The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter photographed the rover on June 27 at the end of a drive that put Curiosity right on the ellipse boundary.

An image from that observation is online.

The landing ellipse is the area within which the rover had a very high probability of touching down when it arrived at Mars on Aug. 5, 2012, PDT (Aug. 6, UTC).

The area needed to meet requrements for providing access to scientifically interesting sites while presenting few landing hazards, such as steep slopes or large boulders.

Many areas of scientific interest have slopes ineligible for landing safety, and Curiosity was designed to have the capability of driving far enough to get to slopes ouside of the landing ellipse.

Since landing, Curiosity has driven slightly more than 5 miles (8 kilometers).