I gather that the Mars Rover project is looking for signs of liquid water, methane and perhaps other indicators of the existence of life, or at least a former decent habitat, on Mars.
If they don’t find any sign of life after a thorough search, are there any bacteria we could shoot up there in a space-pod to start from scratch? Something anaerobic with an appetite for red dust? If not, perhaps we could genetically adapt some to survive?
If we did this to a few planets, at least we could prolong life in the universe past the point where we turn Earth sterile…