An equipment needs only floor to be build on, and wall-connection to a power-supply to work. So:

Refinery: Build a single-file-wall from the base to the asteroid you wish to mine. Build a 4x4 floor adjusted to the wall, lets say 2 squares away from the asteroid. Build a refinery on the floor and deactivate all other refineries. => Miners don't waste time flying back-and-forth AND they waste time at the airlock only twice (at the start and end of their 'shift')

Turrets: Turrets adjusted to the outside of the outer walls of the base will operate and shoot both at incomming enemy crafts and enemies in spacesuits. Also, raders rarely are spowing inside your wall-enclosed space => Build the outline of your future-sized-base using only the perimeter wall (no floors). Build turrets along the outside surface of this wall, and all incoming assoult cradts that try to drill into your base will be shot to peaces after 3 turret bullet-hits. For better protection from random raiders-in-spacesuit, I take advantage of the fact that they tend to fly towards my airlocks: I buld all airlocks one next to the other (i no longer need an airlock close to asteroids since ther is a space-operating-refinery there), and then a hell of crossfire turrets protection pointing at the emty space outside the airlocks doors... Killing-box wihtout a box...

Combining the above, I tent to place some turrets next to the space-refinery my miners work on, so that they are protected from raiders ignoring my airlocks.

Not fully verified hint: Plants also seem to need no air-spaceshuit. So, I tend to place a plant, a monitor and a food-machine next to the refinrery-at-space, hoping to keep my miners a bit more huppy (they are the ones working constantly away of base-funny-moral-booster-items, and I have usually a hard time keeping them form braking their legs at barfights, meaning they are imobilised for a long time till a doctor thinks of helping them, if ever he does before they strarve to death...)