The Imperial Navy.

The Imperial Navy has the responsability of actively patrolling the space of all member worlds. These patrols are to remind the inhabitants of these systems that the wrath of the Empire is never to far away.

Another purpose of the patrols is to intercept and deal with any outlaw traffic as well as conducting spot checks on any vessels encountered and ensuring that all those they encounter are adhering to Imperial law.

A final responsability for the Imperial Navy is to provide transport and orbital support and resupply to the Imperial Marine Corps. This duty is often seen as a punishment detail as it effectively puts control of the vessel into the hands of another service branch.