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Alien life rules
(sh.itjust.works)
Be sure to follow the rule before you head out.
Rule: You must post before you leave.
I am leaps and bounds from an expert, but as I understand it, it's something that's been thought of, certainly. But it's very very difficult to search for something when the paramaters for it are very broad.
On the flip side, we have a decent idea of what it takes to sustain life as we know it. It's far, far easier for us to search for that.