NASA marks Spirit's 6th year on Mars

PASADENA, Calif., Jan. 3 (UPI) -- Spirit, the Martian rover designed to spend three months in unmanned exploration of the Red Planet, marks its six-year anniversary Sunday.

During that time, Spirit has relayed data back to earth that has given scientists with the National Aeronautics and Space Administration an unprecedented view of Mars history. Spirit found evidence of a hot and steamy environment ages ago, while its twin, Opportunity, found data supporting a wet and acidic past on the other side of the planet.

But scientists say Spirit's working life may be coming to an end after 3.2 Mars years. The rover got stuck in the sand nine months ago and efforts to get it moving again have so far failed.

That means scientists may be unable to tilt Spirit's solar panels toward the sun to give it the energy it needs to survive the coming Martian winter in the southern hemisphere.

If the problem can be solved, Spirit could still provide data while stuck in place.

Opportunity, which landed on Jan. 24, 2004, three weeks after Spirit, is still mobile.