Military

AN/ Army/Navy Designation System

On 30 April 1947, the Army and Navy adopted a standard system of designating guided missiles and assigning them popular names. The basic designation consisted of three letters, combinations of A (Air), S (Surface), U (Underwater), and M for missile. The first letter of the designation indicated the missiles origin and the second letter its objective; M was the final letter. An ASM, for example, indicated an air-to-surface missile. A model number, odd for Army and even for Navy, followed the designation letters. For popular names, ASMs would be named after birds of prey, AAMs for other winged creatures, SAMs for mythological terms, and SSMs for astronomical terms or bodies.