Opportunity rover. Mars Exploration Rover Opportunity on the surface of Mars. This is a mosaic compiled from images taken by the navigation camera on the rover after it landed successfully on the planet on 24 January 2004. It landed in a small crater in a region called Meridiani Planum. The lander's solar panels (black, centre) for generating power can be seen. The golf buggy-sized Opportunity rover, and an identical one called Spirit, which landed on the planet 20 days earlier, will study Martian rocks and look for water on the planet.