The MX Designation System was introduced by the Experimental Engineering Section of the US Army Air Corps Materiel Division in 1941. MX designations were used for experimental weapon system programs, including jet- and rocket-powered systems, precision-guided munitions, and other systems designed and manufactured by U.S. defense contractors under contracts provided by the U.S. Army Air Corps from 1941, the

United States Army Air Force The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

(1945–1947), and the

United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...

(1947–1954). Some MX designated programs were also pursued by

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

. For example MX-554 led both to the Army JB-2 as well as the Navy KGW. The MX designation system was not used by any other US military organization other than in reference to the USAAC, USAAF and USAF programs. The "MX" indexation system was in use until July 1, 1954, but certain weapon programs have been referred to by their "MX" designation during their project development since 1954, such as the

SM-65 Atlas The SM-65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U.S. Air Force by the Convair Division of General Dy ...

(MX-1593). The

LGM-118 Peacekeeper The LGM-118 Peacekeeper, originally known as the MX for "Missile, Experimental", was a MIRV-capable intercontinental ballistic missile (ICBM) produced and deployed by the United States from 1985 to 2005. The missile could carry up to twelve Mark ...

was given the project title MX for Missile Experimental but was not part of the MX series of designations as the program did not exist until well after the MX designation system had been discontinued.

References

Further reading