Widely dispersed missile silos were nearly featureless in the open landscape, and most equipment was deep underground. This silo is near Malmstrom Air Force Base, Great Falls, Mont. (U.S. Air Force photo)
A typical two-man Minuteman IA launch crew. These crewmen served with the 10th Strategic Missile Squadron, 341st Strategic Missile Wing, Malmstrom Air Force Base, Mont. The 341st was one of six Minuteman wings. (U.S. Air Force photo)
Note: The Missile & Space Gallery will close temporarily, beginning Dec. 8, 2014, for approximately five months for construction linking the gallery to the museum's new fourth building. This exhibit will not be accessible during that time. Click here for more information.
The Minuteman missile concept pushed rocket technology to a new level and it vastly improved U.S. nuclear strategic deterrence. Minuteman was the first U.S. intercontinental ballistic missile (ICBM) to use solid fuel, permitting quick-response launches in case of attack. The first Minuteman missiles became operational in late 1962.
Minuteman IA missiles like the one on display were the first generation of a revolutionary new family of ICBMs. They used solid rather than liquid fuel, and so could be launched in less than a minute -- hence the "Minuteman" name, referring to colonial American farmers who could be ready to defend their homes at a moment's notice. In contrast to Minuteman, older missiles like Atlas and Titan I took up to half an hour to fuel and launch. They were also complex and costly, requiring close monitoring and constant maintenance, and their propellants could be dangerous. Moreover, they tended to be vulnerable to attack.
Minuteman's advantages combined speed, low maintenance, high reliability, high "survivability" from attack, and low cost. The U.S. Air Force had been studying solid fuels since the early 1950s, and using solid fuel was important because it meant that the missile could be stored unattended for long periods. In addition, Minuteman was small enough to be housed in very strong unmanned underground silos able to survive nuclear attack.
In 1958, guided by the Air Force Ballistic Missile Division, industry began work on the new three-stage missile. Boeing was the overall contractor, and important parts of the missile came from the firms Autonetics (guidance); Aerojet, Hercules and Thiokol (rocket stages); and Avco (re-entry vehicles). The USAF planned to deploy up to 1,600 Minutemen -- later revised to 1,000 and then 950 -- making the system a very strong nuclear deterrent.
After a series of successful test launches, the USAF began rapidly deploying Minuteman missiles. Minuteman IA missiles like the one on display were based at Malmstrom Air Force Base, Mont., in the 341st Strategic Missile Wing, the first of six Minuteman wings. Malmstrom's first flight of 10 missiles went on operational alert on Oct. 22, 1962. Later models would be based at Malmstrom and five other bases in western states including South Dakota, North Dakota, Wyoming and Missouri. These states had thousands of square miles of open space surrounding the bases, making them ideal for Minuteman operations.
Each Minuteman wing contained three or four 50-missile squadrons divided into 10-missile flights. The Minuteman force grew very quickly as the US Army Corps of Engineers constructed the relatively small, easy to build silos using prefabricated sections. By 1966, 1,000 silos were complete, and all their missiles were operational by mid-1967.
Each underground launch control center, with two USAF officers on constant alert, controlled ten missiles typically separated from one another by at least three miles of open land. The launch crews rotated regularly, and they maintained very high proficiency in the awesome responsibility of operating nuclear weapons. The crews, missiles and silos received support from technical, administrative, service, security and many other personnel at the wings' parent bases.
An Evolving System
The Minuteman IA on display (designation LGM-30A) represents one of 150 deployed at Malmstrom AFB between 1962 and 1969. Improved range and accuracy in later models enabled their deployment at U.S. bases farther from their targets in the former Soviet Union.
Like any ICBM, Minuteman IA was a complex system. The rocket's three powerful stages burned one after the other to send a single nuclear warhead on a free-falling or ballistic path to its target. To hit a target thousands of miles away, Minuteman used a precise guidance system of gyroscopes, accelerometers, and a computer that was powerful for its time.
Sensing the missile's movement, the guidance unit swiveled rocket motor nozzles to keep the missile on course. It also told the three stages when to fire and separate, and determined the right moment to release the re-entry vehicle containing the nuclear warhead.
The re-entry vehicle at the tip of the missile free-fell to its target using gravity alone. To protect the warhead inside from the heat of atmospheric re-entry, the vehicle was covered with special materials called "ablative" coatings that carried away heat by burning and charring away as the vehicle streaked earthward.
The missile on display came to the museum in 1971. Later Minuteman models included Minuteman IB (LGM-30B), II (LGM-30F) and III (LGM-30G). Over the years, the Minuteman series received various upgrades with improved motors, guidance, re-entry vehicles, and warheads. Minuteman III, also on display in this gallery, is still in service and is projected to be a main nuclear deterrent well into the 21st century.
Height: 53.8 ft. Weight: 65,000 lbs. Range: Designed for 5,000+ miles Speed: 15,000 mph Propulsion: Stage 1--Thiokol, 210,000 lbs. thrust; Stage 2--Aerojet, 60,000 lbs. thrust; Stage 3--Hercules, 35,000 lbs. thrust Guidance: All inertial, Autonetics Division of Rockwell Warhead: Nuclear, re-entry vehicle by Avco
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