But it's not like they take old spacecraft sterilized with these solutions, bring them back, and try the liquid again? Yes, I'm sure there is some kind of sele

But it's not like they take old spacecraft sterilized with these solutions, bring them back, and try the liquid again? Yes, I'm sure there is some kind of selection, but it should be more of a one-shot affair, not a continous cycle, like how it with anti-biotics and resistant strains.