Bonneville Crater at Gusev Site. This red dish is Bonneville Crater as seen by Spirit, one of NASA Twin Rovers mission to Mars. Spirit landed in January 2004 at Gusev Crater, a vast martian crater. After Spirit rolled off its landing platform it spent some time exploring its immediate surroundings before heading northeast to this crater. En route it performed various science at targets of interest like rocks, sand ripples or flat dusty surfaces dubbed "hollows". Bonneville is 656 ft (200 m) wide. A part of crater continues right of picture. Such places are of interest for NASA scientists as they are providing access to deeper martian layers. This crater might give access to Gusev site deepest layers and provide a better answer to whether this site had a watery past. Opportunity, Spirit's twin, definitely brought evidence that Meridiani Planum, a place where it landed just on the other side of Mars, endured a strong, lasting, life-friendly past, bringing an answer yes to a part of Mars having been possibly hospitable to life. picture courtesy NASA/JPL/Cornell