The great trek is over: Spirit officially mired.

Sad news indeed. After an extraordinary 6-year mission, the Spirit rover on Mars has been officially re-designated by NASA as a Stationary Research Platform. This decision follows months of effort by engineers to find a way of freeing the rover from a sand trap that had left its wheels spinning. But the science is not over for Spirit and it will continue to gather data, confounding estimates that on landing on Mars, it would only last 3 months. Over 6 years later and it is still functioning, plus of course its sister probe Opportunity is still operating after a similar period of activity.