Gallery: Diving For Spacewalks Is Way Tougher Than You Think

There's so much resistance from the suit and the water every motion takes tremendous effort. You might not guess it from my pictures, but I'm actually pretty fit, and I was exhausted by the end of the day. The hardest thing to get used to was moving up and down in the water column. I've been diving so long controlling my buoyancy is basically a force of will at this point, having to actually crawl and direct myself up and down was such a weird feeling.

So, for a real astronaut to pass their final evaluation they have to do a flawless incapacitated crew member rescue. this is actually very difficult as safely manipulating another suit is even more tiring and cumbersome than just moving your own. not only that but the airlock is very small, and safely (using proper tether technique) hooking someone else up into it is a surprisingly complex procedure where you have zero extra space to work with. Thirty minutes usually ends up being hardly enough time for the new guys, and even a vet will take more than 20.