<P> Development of the Minuteman began in the mid-1950s as the outgrowth of basic research into solid fuel rocket motors which indicated an ICBM based on solids was possible . Such a missile could stand ready for extended periods of time with little maintenance, and then launch on command . In comparison, existing U.S. missile designs using liquid rocket propellant required a lengthy fueling process immediately before launch, which left them open to the possibility of surprise attack . This potential for immediate launch gave the missile its name; like the Revolutionary War's Minutemen, the Minuteman was designed to be launched on a moment's notice . </P> <P> Minuteman entered service in 1962 as a weapon tasked primarily with the deterrence role, threatening Soviet cities with a second strike countervalue counterattack if the U.S. was attacked . However, the development of the U.S. Navy's Polaris missile, which addressed the same role, allowed the Air Force to modify Minuteman into a weapon with much greater accuracy with the specific intent of allowing it to attack hardened military targets, including Soviet missile silos . The Minuteman - II entered service in 1965 with a host of upgrades to improve its accuracy and survivability in the face of an anti-ballistic missile (ABM) system the Soviets were known to be developing . Minuteman - III followed in 1970, using three smaller warheads instead of one large one, which made it difficult to attack because the ABMs would have to hit all three widely separated warheads to be effective . Minuteman - III was the first multiple independently targetable reentry vehicle (MIRV) ICBM to be deployed . Each missile can carry up to three thermonuclear weapons, which have a yield in the range of 300 to 500 kilotons . </P> <P> Peaking at 1,000 missiles in the 1970s, the current U.S. force consists of 440 Minuteman - III missiles in missile silos around Malmstrom AFB, Montana; Minot AFB, North Dakota; and F.E. Warren AFB, Wyoming . By February 2018 this will be reduced to 400 armed missiles, with 50 unarmed missiles in reserve, and four non-deployed test launchers to comply with the New START treaty . The Air Force plans to keep the missile in service until at least 2030 . It is one component of the U.S. nuclear triad--the other two parts of the triad being the Trident submarine - launched ballistic missile (SLBM), and nuclear weapons carried by long - range strategic bombers . </P> <P> Minuteman owes its existence largely to the efforts of then Air Force Colonel Edward N. Hall . In 1956, Hall was put in charge of the solid fuel propulsion division of General Schriever's Western Development Division, which had originally been formed to lead development of the Atlas and Titan ICBMs . Solid fuels were already commonly used in rockets, but strictly for short - range uses . Hall's superiors were interested in short and medium range missiles with solids, especially for use in Europe where the fast reaction time was an advantage for a system that might be attacked by Soviet aircraft . But Hall was convinced that they could be used for a true ICBM with 5,500 nautical miles (10,200 km; 6,300 mi) range . </P>

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