Spirit, the poor Mars Rover that's been stuck in Martian sand since last year, has actually contributed to a pretty fantastic discovery in its sedentary months: the evidence of subsurface water on Mars.
To recap: Spirit, one of two plucky Mars Rovers that had finished their initial missions in 2004 and had embarked upon, as NASA calls them, "bonus missions" ever since, slipped through Mars' crust in April 2009 and ended up stuck in the soft sand underneath. Try as it did to back itself out, it remained stuck, and seven months later a second wheel broke down. Fromhttp://cache.gizmodo.com/assets/images/4/2010/10/160x120_500x_500x_spirit-rover-mars.jpg then it's been considered a stationary scientific outpost.
But just as everything in the immediate proximity of your couch becomes slightly more fascinating when your leg is broken, the scientists let the Spirit Rover settle in and conduct some in-depth tests on the soil immediately surrounding it. Those tests found varied composition in the layers of soil underneath the Rover, with generally insoluble materials appearing near the surface and more soluble ones being found deeper down. This is leading scientists to hypothesise that water, perhaps in the form of frost or melted snow, has seeped down into the Martian ground recently and repeatedly.
The Spirit is currently in a low-power hibernation mode as he endures winter, and we'll have to wait until March, when his solar panels will be in position to collect sun, to see if he wakes up. But in the meantime, good work, little guy - you're a study in perseverance. [NASA]