Orbital gates work on the same principles as the smaller gates. The gate’s portal is one-way except for energy transmission. Radio waves and such can pass through a gate in both directions, allowing FTL communication. Any matter trying to enter a gate the “wrong way” simply passes through the ring with no effect. Physically obstructing the space inside the ring will prevent a gate from forming, as will activating the emergency shutdown nodule.
Objects that pass through the ring do not transport until their entire mass has passed over the threshold and the receiving gate has determined that the object will pass through without incident.
Orbital gates are usually mated to a spaceport or space elevator. These platforms are host to a small contingent of Turai or local planetary enforcement personnel and have an array of anti-spacecraft weaponry.
The gates are never allowed to have their "output" side facing their host planet.
A side effect of relying on passing spacecraft through a limited area means that the Imperium does not have any spacecraft wider than the 500 feet necessary to clear the gates.