every astronaut had to get certified in the basics of EVA by doing four runs in the pool. Before we could get in the water in the space suit, we had to pass a high-grade scuba certification. I had a civilian scuba license, but this was a more difficult test. The hardest thing for me was the unassisted ditch and don. You had to swim down to fifteen feet, ditch your mask and flippers, go back to the surface, tread water, then dive back down, don the gear, clear your mask, and get back to the surface with no water inside your mask.
