The Royal Armed Forces
The Kingdom of Orion maintains a Royal Star Fleet with attached Marine Corps to repel foreign attack. The bulk of the forces are at lonely bases on the rim of the kingdom and at strategic points in the interior. In fact, since there hasn’t been an interstellar war in nearly fifty years, there are more vessels in mothballs awaiting reactivation than there are those on active duty.
There is no royal army, but each planet has troops of its own to due ground fighting. They are duty bound to answer the summons of the king at need. Many planets have their own small space fleets as well, these are usually a few corvettes and fighter wings used for piracy suppression and patrol work.