1963 United States Tri-Service missile and drone designation system

On June 27, 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 It superseded the separate designation systems the Air Force and Navy had for designating US guided missiles and drones, but also a short-lived interim USAF system for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.

Explanation
The basic designation of every guided missile is based in a set of letters, which are in sequence. The sequence indicates the following:
 * The environment from which the weapon is launched
 * The primary mission of the weapon
 * The type of weapon

Examples of guided missile designators are as follows:
 * AGM - (A) Air-launched (G) Surface-attack   (M) Guided missile
 * AIM - (A) Air-launched (I) Intercept-aerial (M) Guided missile
 * ATM - (A) Air-launched (T) Training         (M) Guided missile
 * RIM - (R) Ship-launched (I) Intercept-aerial (M) Guided missile
 * LGM - (L) Silo-launched (G) Surface-attack  (M) Guided missiles

The design or project number follows the basic designator. In turn, the number may be followed by consecutive letters, representing modifications.


 * Example:
 * RGM-84D means:
 * R - The weapon is ship-launched;
 * G - The weapon is designed to surface-attack;
 * M - The weapon is a guided missile;
 * 84 - eighty-fourth missile design;
 * D - fourth modification;

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.