> In space, legs are not required.

Maybe not a hard requirement, but they are very useful. Scott Kelly talks about the hard callouses he had on his feet because you end up using your feet to navigate and hook yourself into place a lot.

https://www.businessinsider.com/scott-kelly-weirdest-thing-y...

Leaving the spacecraft on the ground due to an emergency might require the escapee to be fully ambulatory, though.

You can lack legs and be fully ambulatory. (And murdery, but that's beside the point here.)

https://en.wikipedia.org/wiki/Oscar_Pistorius

Running on the track is not the same as climbing out of a cramped pressure vessel.

Sure, and if NASA can't find a way for an amputee to safely do that, they'll disqualify them for flight. Some people with fully functional legs fail the egress tests, too.

They should be given a chance to prove the ability, rather than being dismissed out of hand.