Spirit rover's lander on Mars. Fisheye lens view from the rear of the Mars Exploration Rover Spirit after it left its lander, showing the lander on the Martian surface. The lander and rover landed on Mars on 4 January 2004. Wheel tracks show the path taken by Spirit, and one of its wheels is at lower right. Spirit left the lander on 15 January 2004 to begin its exploration of the Martian surface. The rover had to turn on the lander to use the landing ramp seen (white), negotiating a 10 centimetre drop off the ramp. This picture was taken by Spirit's rear hazard avoidance camera. Spirit is one of two rovers that will study Martian rocks and look for water on the planet.