The doors are operated by undocking one of the two hubs on the bottom of the door. The force of the undocking provides the energy to move the door without requiring thruster propellent. However the station or ship should have station keeping engines ready because sometimes the impact from open or closing a door can cause the station to shift slightly.
The design of this door allows it to be extended to cover any size opening. It can be adjusted by adding or removing trusses.