I don't really know of too many sophisticated military weapons that don't require contractor support. The military doesn't really hire professional engineers. The involved enlisted serve as maintenance crew and understand basics and know how to read manuals and use tools, officers fly and command things. Even the vocational schools for the enlisted that learn to do the maintenance on such equipment are often taught by civilians. Engineering takes a lot of schooling which would be on the level of an officer, but officers are commanders. Officers are management, not usually individual contributors except for maybe in the medical field where nurses are officers.