At the start of the game, when the ship has no atmosphere, the crew is already wearing spacesuits. As the player builds the systems necessary for an atmosphere and the ship reaches a sufficient oxygen level, the crew automatically strips off their spacesuits and leaves them on the floor. If the player sets a spacesuit storage location, the crew will deposit their suits there instead.
The player can order the crew to put their spacesuits back on, but the crew will not take oxygen from the suit's tanks unless the atmosphere can't sustain them. Spacesuits with empty oxygen tanks can be refilled using a spacesuit pod connected to an oxygen supply.