I liked to imagine astronauts as individuals who excelled so much in their given fields that they stood out and were actively recruited by NASA. Instead, I find

I liked to imagine astronauts as individuals who excelled so much in their given fields that they stood out and were actively recruited by NASA. Instead, I find out that NASA posts job postings and interviews people just like everyone else Possibly if your job is "test pilot" then you might still get recruited by NASA. For scientist-astronauts, though, I'm guessing that being spectacularly brilliant in your particular field is neither sufficient nor necessary to be a good astronaut; better to hire good but not necessarily field-leading science-trained types who also excel in the various other qualities which you need in order to strap yourself to a giant bomb and perform brilliantly in adverse circumstances for several days without enough sleep.