(Sen) - NASA's surviving Mars rover Opportunity is gearing up to begin exploring again, after weeks spent sitting out the local winter.
The robotic buggy was parked up on a slope at a 15-degree angle facing the Sun by its controllers back in February as a precaution.
Though Opportunity is near enough to the martian equator for the sun never to get too low in the midday sky, a coating of dust was reducing the effectiveness of the solar panels that provided power.
But winter solstice in Opportunity's region on Mars passed on March 30. Now scientists at NASA's Jet Propulsion Labratory (JPL) say that the improved angle of sunlight, plus a modest improvement in how clean the panels are of dust, means the rover has now built up enough energy to begin moving again.
They will therefore soon back Opportunity down from her perch at a site called Greeley Haven on the rim of Endeavour Crater and put it back on level ground.
The rover will then begin again to explore the north end of Cape York on the crater's edge, more than eight years and five winters after it landed in January 2004. Researchers want it to go in search of clay minerals that a Mars orbiter's observations indicate lie on Endeavour's rim.
Mars scientists also want to use weeks of radio signals collected from Opportunity while it was stationary to measure any wobble in the planet's rotation that would indicate whether the planet has a molten core.
Diana Blaney, deputy project scientist for the mission at JPL, said: "The top priority at Greeley Haven is the radio-science campaign to provide information about Mars' interior."
An impression of a NASA Mars Exploration Rover on the surface. Credit: NASA
Opportunity is now 23 km (14 miles) south-east of the spot in Eagle Crater where it originally bounced to landing within a martian region called Meridiani Planum.
The initial missions for the rover and its sister buggy Spirit on the other side of Mars were scheduled to last just 90 days, so Opportunity's healthy state is amazing.
After a remarkable run of its own, Spirit became trapped in sand in November 2009 after two of its six wheels stopped working. Power ran out and nothing has been heard from it since March 2010.