NASA Mars Rover Opportunity’s Time in Purgatory

Traveling to etched terrain turned out to be an aesthetic bonus, but a bit of a mobility challenge. Ripples in the terrain, presumably formed by wind, look like still soil waves. As pleasing as they are to the eye, they can pose a danger to Opportunity. An unexpected hiatus came when the rover got stuck in a ripple called “Purgatory.” Talented rover drivers eventually eased Opportunity out, and put their lessons learned to good use.

“Now we have the rover stop about every five meters (16 feet) to conduct a slip check,” Maxwell said. “It slows us down, but it’s safer. We encountered a test case with the ripple Telluride,’ and were relieved Opportunity did what she was supposed to do!”

This mosaic of navigation-camera frames from NASA’s Mars Exploration Rover Opportunity, presented in a vertical projection, shows the rover’s position after it dug itself to wheel-hub depth in a small dune during its 446th martian day, or sol (April 26, 2005). The colors are coding for information about relative elevations in the surrounding area. Red areas are the highest in the image, green areas the lowest. The difference between red and green is about 70 centimeters (28 inches). Image credit: NASA/JPL-Caltech