if you are in a world without air or with radiation / temperature levels higher then ur suit. or maybe with low gravity. Building a spacestations allows to have NO effects while in the base. A space Station can be build in any shape as long as it uses Airgenerators.
A loom = a air generator. simply make a loom and ur set.
place down the loom where u want air/gravity/protection this can be either in the floor or the ceiling. Make sure if its in the floor that the bottom of the loom is enclosed and if its in the ceiling that the top of the loom is enclosed. Next SHIFT right click the loom it will show green sparkles with the radius its generating air in. The loom will remember the Status so if the server restarts there is still air there.
Simply destroy the loom.
If u do not cover the top if on ceiling or the bottom if in the floor then it always refers back to a floor layout thus so only generating air on top of it