Nasa's Opportunity rover is little more than a bluish speck on the rim of the Santa Maria crater on the surface of Mars in an image taken by the Mars Reconnaissance Orbiter's high resolution camera.

Opportunity has confounded all expectations by continuing to operate years after its primary mission was over. The rover was dispatched to Mars in 2003, with a twin called Spirit that fell silent in March last year after getting a wheel stuck in the soil.

A photograph was taken by the orbiter on 1 March from an altitude of more than 155 miles (250km) as Opportunity extended its robot arm to take close-ups of a rock called Ruiz Garcia. Tracks left by the rover as it approached are visible to the west of the crater.

It has been gathering information about the geology of the relatively fresh, 90m-wide crater that will help explain how it formed and how erosion and the Martian weather have shaped it since. The bright orange streaks are material kicked up by the impact.

The rover will soon leave the edge of Santa Maria and trek for 3.7 miles (6km) to a larger crater called Endeavour, where the Martian soil contains hydrated sulphates and phyllosilicates that formed in a wetter past.