The Orbital Relay is a Space Marine Building in Dawn of War. The primary purpose of this Building is to allow the player access to Terminator Units at the Chapel-Barracks and as well as a deep striking platform for Infantry, Heavy Infantry and Walking Vehicles. Constructing an Orbital Relay costs 250 Requisition and 500 Power, making it the second most expensive structure of the Space Marines behind the Stronghold. Players cannot build the Orbital Relay more than once. The building features 1500 Hit Points and like all artificial constructs, it has no Morale.
Deep Strike: Deep Strike any Infantry, Heavy Infantry and Walking Vehicles except Assault Marines. The Orbital Relay has 6 available slots to store units for Deep Striking. Both Infantry and Heavy Infantry take up 1 slot while Walking Vehicles take up 2 slots. Deep Striking takes 10 seconds for the drop pod to deploy and it takes 30 seconds to charge a unit that enters the Orbital Relay on foot. The drop pod used to deliver the unit or squad is even a weapon in and of itself, dealing damage and knockback to any unit within the area of effect.
This structure allows you to Deep Strike most infantry units and Dreadnoughts and enables the Orbital Bombardment special ability. You walk your units inside and after a delay you can drop them anywhere on the map (that's not covered by fog of war). The obvious tactic is using it to drop melee units on/behind enemies but of course you can put a ranged squad in a good position or use it for transportation on large maps. You should hotkey your Orbital Relay to a number for ease of use. However, since Orbital Relays cannot be built multiple times, make sure to build them strategically, such as near choke points where your units will most likely encounter the enemy.