Airlocks are represented in-game by yellow doors.
Airlocks can be opened by typing "a" followed by a number corresponding to the airlock. (eg. a1, a2, a3)
Typing "a1" will toggle the open status of the airlock, closing an open airlock and opening a closed airlock.
Opening an airlock will expose the room and any connected rooms with open doors to space which can result in depressurization. Radiation will also leak into the room if the airlock is left open for too long.
Opening an airlock that you are not docked at also has a chance to destroy objects in the room such as any of the doors, power inlets, interfaces, or defense turrets when the room depressurizes.
On volatile Derelicts, Airlocks on the Derelicts have a chance to fail. After a minute, the Airlock's seal will fail and opens up permanently exposing the room the Airlock is in, to the Vacuum of space and Radiation.
The player's ship can connect to an airlock by using the "dock" command. (Docking can also stabilize the seal on a failing airlock)