NASA's ageing Mars exploration rover Opportunity is heading for Greeley Haven for the winter - a site with a sun-facing slope to catch the meagre rays of our star on its solar panels.

False colour image of Greeley Haven taken by Opportunity. Credit: NASA/JPL-Caltech/Cornell/Arizona State Univ

The thick layer of dust on Opportunity's electricity-generating panels means it has to stay in the sun as much as possible to get enough power to survive the Martian winter, which is why the space agency has sent it to this particular outcrop.

Before this Martian year, Opportunity didn't need to take any precautions for the several months of shortened daylight before and after the southern winter solstice on March 30, but this time around the panels will be too dirty to pick up enough light.

The winter site is named after planetary geologist Ronald Greeley, who was a member of the science team for the Mars rovers, and as well as keeping Opportunity juiced up, it will also give the rover some science stuff for its robotic arm to look at.

Opportunity will be conducting a radio-science investigation of the interior of Mars, studying tiny wobbles in the planet's rotation to figure out more about its core. The rover will also inspect the mineral composition of the outcrop and record a full-circle, colour panorama of the scenery.

Greeley Haven is on the Cape York segment of the rim of the Endeavour Crater, which Opportunity reached five months ago after a three-year journey from Victoria Crater, which it studied for two years.

Neither Opportunity nor its fellow rover Spirit were ever meant to last this long, having both completed their primary missions in 2004.

Last year, Spirit got stuck after losing two of its six wheels and wasn't able to make it to a sunny place to wait out the winter. NASA ended attempts to contact the rover in May, when it was clear the plucky trundler hadn't survived the icy temperatures.

While Opportunity battles on, NASA's focus is also on its brand shiny new rover, Curiosity, which is headed to the Red Planet at the moment and is expected to reach its destination in August this year. ®