[piva00]

They don't need to be an astronaut to wear the prototypes and check how they fit, how they allow you to move or not move, how convenient it is to access the tool belt, etc.

[robertlagrant]

They do need to to test it in space or in a rocket taking off/landing. Otherwise they're just running unit tests.

[ofrzeta]

The equivalent would be just wearing a helmet or a sleeve. If they are wearing the whole suite they are end to end testing in staging opposed to production.

[eru]

Hmm, maybe. But using a product in anger is very different from just kicking the tires.