Spirit rover on Mars. Forward-looking view from the Mars Exploration Rover Spirit on the Martian surface. The rover had just completed the longest- ever drive by a rover on another planet, driving over 21 metres to reach the sand ripples seen at centre left. The feature is called a bedform, and has been created by wind erosion and deposition. The parallel lines are thought to show that the wind direction is constant. Two of the rover's six wheels are seen. Spirit landed in the Gusev Crater near the Martian equator on 4 January 2004. This image was taken on 9 February by the front hazard- avoidance camera.