I don't have a clue. But I would not pretend to know that life must be water based, as if this was an obvious fact. There are lots of things we do not know. I

I don't have a clue. But I would not pretend to know that life must be water based, as if this was an obvious fact. There are lots of things we do not know. I would still be excited when finding water in other planets, though. In general, approaches such as SETI seem to me much less biased by our own nature and much more likely to show results. A comparable aproach for simple life forms, looking for effects instead of causes, seems more sensible to me.