[Jason]

NASA's twin Mars rovers have outlasted their planned three-month missions for so long that they seem indestructible. Nearly six years on, their presence on the Red Planet is taken for granted, as if they are immutable parts of the Martian landscape.

But we may soon have to confront a new reality. Spirit, which has always suffered more hardships than Opportunity, is facing its toughest challenge yet. When New Scientist went to press, the rover was set to begin a risky push to free itself from a sand trap it has been mired in for six months. Mission engineers say it may not survive the attempt. "She's in a very precarious situation, and we don't know for sure if we're going to get her out," says rover driver Scott Maxwell of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

Spirit encountered its latest difficulty in April, as it made its way south along the edge of Home Plate, a plateau of hardened ash that has been its main haunt for more than three-and-a-half years. Its wheels started to slip in the soft, sandy soil filling an 8-metre-wide crater. By the time the rover team decided to stop driving, Spirit was essentially just spinning its wheels.

Mars rover battles for its life - space - 11 November 2009 - New Scientist

[Ashlar2006]

I was just watching a show on the NatGeo Channel about these two rovers . That Spirit was about to loose power because it's solar panels where covered in dust and there was no wind in it's area of exploration , and when it was looking most dire it received a much needed gust of wind . I can't believe they are still going .