1963 United States Tri-Service missile and drone designation system
In 1963, the U.S. Department of Defense established a designation system for guided missiles and drones jointly used by all the United States armed services. It superseded the separate designation systems the Air Force and Navy had for designating US guided missiles and drones, but also a short-lived interim USAF system for guided missiles and rockets. History. On 11 December 1962, the U.S. Department of Defense issued Directive 4000.20 “Designating, Redesignating, and Naming Military Rockets and Guided Missiles”. It was implemented via Air Force Regulation (AFR) 66-20, Army  Regulation (AR) 705-36, Bureau of Weapons Instruction (BUWEPSINST) 8800.2 on 27 June 1963. This system was later subsumed under the DoD Joint Regulation Designating and Naming Military Aerospace Vehicles in 1971. Explanation. The basic designation of every guided missile is based in a set of letters, which are in sequence. The sequence indicates the following: Examples of guided missile designators are as follows: The design or project number follows the basic designator. In turn, the number may be followed by consecutive letters, representing modifications. In addition, most guided missiles have names, such as Harpoon, Tomahawk, Seasparrow, etc. These names  are retained regardless of subsequent modifications to the missile. Prefixes. An X preceding the first letter indicates an experimental weapon, a Y preceding the first letter means the weapon is a prototype, and a Z preceding the first letter indicates a design in the planning phase.