An active missile decoy designed and built by an American/Australian collaboration. Deployed on some USN and RAN warships, Nulka is a rocket propelled, disposable, offboard, active decoy designed to seduce anti-ship missiles away from their targets. The United States Navy (USN) is the branch of the United States armed forces responsible for naval operations. ... Royal Australian Navy Ensign The Royal Australian Navy (or RAN) is the navy of Australia and part of the Australian Defence Force. ...