The thing that sets Mars apart is that it is the one planet that is enough like Earth that you can imagine life possibly once having taken hold there.
Steve SquyresThese rovers are living on borrowed time. We're so past warranty on them. You try to push them hard every day because we're living day to day.
Steve SquyresWe have concluded that the rocks here were once soaked in liquid water. It changed their texture, and it changed their chemistry. We've been able to read the tell-tale clues the water left behind, giving us confidence in that conclusion.
Steve Squyres