Anime involving astronauts training underwater
Episode 20 of Planetes features an isolation test and they have to build a model of the ship that will take them to Jupiter:







Additionally, during that episode, in order to test the isolation adaptability of the candidates, they turned off the oxygen and watched as team after team hit their emergency buttons without having a way to cope



And the way the main character's team dealt with the issue was turn down the temperature so that they use less oxygen: