| LGM-30 Minuteman | |
|---|---|
| Type | Intercontinental ballistic missile |
| Service history | |
| In service | 1962 (Minuteman I), 1965 (Minuteman II), 1970 (Minuteman III) |
| Used by | United States |
| Production history | |
| Manufacturer | Boeing |
| Unit cost | $7,000,000 |
| Specifications | |
| Weight | 78,000 lb (35,300 kg) |
| Length | 59 ft 9.5 in (18.2 m) |
| Diameter | 5 ft 6 in (1.7 m) (1st stage) |
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| Warhead | Nuclear W62, W78, or (2006–) W87 |
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| Engine | Three solid-propellant rocket motors; first stage – Thiokol TU-122 (M-55); second stage – Aerojet-General SR-19-AJ-1; third stage – Aerojet/Thiokol SR73-AJ/TC-1 |
| Operational range |
8,100 (Exact is Classified) miles (13,000 km) |
| Flight altitude | 700 miles (1,120 kilometers) |
| Speed | Approximately 15,000 mph (Mach 23, or 24,100 km/h, or 7 km/s) (terminal phase) |
| Guidance system |
Inertial |
| Accuracy | 150 m CEP |
| Launch platform |
Missile Silo |
The LGM-30 Minuteman is a U.S. nuclear missile, a land-based intercontinental ballistic missile (ICBM). As of 2010, the version LGM-30G Minuteman-III is the only land-based ICBM in service in the United States. It is one component of a nuclear triad, which is complemented by the Trident submarine-launched ballistic missile (SLBM) and by nuclear weapons carried by long-range strategic bombers.
The letter “L” in “LGM” indicates that the missile is silo-launched; the “G” indicates that it is designed to attack ground targets; the “M” indicates that it is a guided missile.[1]
The name “Minuteman” comes from the Revolutionary War’s Minutemen. It also refers to its quick reaction time; the missile can be launched in about 1 minute. The Air Force plans to keep the missile in service until at least 2030.[2][3]
The current US force consists of 450 Minuteman-III missiles[4] in missile silos around F.E. Warren AFB, Wyoming; Malmstrom AFB, Montana; and Minot AFB, North Dakota.[1]
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The previous versions, Minuteman-I and Minuteman-II, were in service from 1962 until 1997.
The Minuteman had two innovations that gave it a long practical service life: a solid rocket booster, and a digital flight computer. This computer was one of the very first recognizably modern embedded systems.
The solid rocket booster made the Minuteman faster to launch than earlier ICBMs, which used liquid rocket propellants.
A reprogrammable inertial guidance system was a major risk in the original program. When first proposed, no one had built a digital computer that would fit in a missile. One program, the SM-64 Navaho, had already failed to produce such a system.
A digital computer was essential to obtain the accuracy gains that kept this weapon effective throughout the Cold War. As the Defense Mapping Agency (now part of National Geospatial-Intelligence Agency) more accurately mapped mass concentrations in the Earth, the inertial guidance software could be updated and loaded into the missiles to make them ever more accurate by having them compensate for these sources of gravity. Another gain that persuaded program managers to accept the risk of the computer was that the computer could also be used to test the missile. This saved a large amount of weight in cables and connectors.
See also W56 Warhead
The LGM-30A Minuteman-I was first test-fired on 1 February 1961,[5] and entered into the Strategic Air Command’s arsenal in 1962, at Malmstrom Air Force Base, Montana; the “improved” LGM-30B became operational at Ellsworth Air Force Base, South Dakota, Minot Air Force Base, North Dakota, F.E. Warren Air Force Base, Wyoming, and Whiteman Air Force Base, Missouri in 1963. All 800 Minuteman-I missiles were delivered by June 1965. Each of the bases had 150 missiles emplaced. F.E. Warren AFB had 200 of the Minuteman 1B's. Malmstrom AFB had 150 of the Minuteman I and about five years later added 50 of the Minuteman II similar to those installed at Grand Forks AFB, ND.
The Minuteman-I Autonetics D-17 flight computer used a rotating air bearing magnetic disk holding 2,560 “cold-stored” words in 20 tracks (write heads disabled after program fill) of 24 bits each and one alterable track of 128 words. The time for a D-17 disk revolution was 10 ms. The D-17 also used a number of short loops for faster access of intermediate results storage. The D-17 computational minor cycle was three disk revolutions or 30 ms. During that time all recurring computations were performed. For ground operations the inertial platform was aligned and gyro correction rates updated. During flight, filtered command outputs were sent each minor cycle to the engine nozzles. Unlike modern computers, which use descendants of that technology for secondary storage on hard disk, the disk was the active computer memory. The disk storage was considered hardened to radiation from nearby nuclear explosions, making it an ideal storage medium. To improve computational speed, the D-17 borrowed an instruction look-ahead feature from the Autonetics-built Field Artillery Data Computer (M18 FADAC) that permitted simple instruction execution every word time.
The D-17B and the D-37C guidance and control computers were integral components of the Minuteman I and II missiles, respectively, which formed a part of the United States ICBM arsenal. The Minuteman III missiles, which use D-37D computers, complete the 1000 missile deployment of this system. The initial cost of these computers ranges from about $139,000 (D-37C) to $250,000 (D-17B).
The LGM-30F Minuteman-II was an improved version of the Minuteman-I missile. Development on the Minuteman-II began in 1962 as the Minuteman-Is entered the Strategic Air Command’s nuclear force. Minuteman-II production and deployment began in 1965 and completed in 1967. It had an increased range, a greater throw weight and guidance system with better azimuthal coverage, providing military planners with better accuracy and a wider range of targets. Some missiles also carried penetration aids, allowing higher probability of kill against Moscow’s anti-ballistic missile system. The payload consisted of a single Mk-11C reentry vehicle containing a W56 nuclear warhead with a yield of 1.2 megatons of TNT (5 PJ).
The major new features provided by Minuteman-II were:
System modernization was concentrated on launch facilities and command and control facilities. This provided decreased reaction time and increased survivability when under nuclear attack. Final changes to the system were performed to increase compatibility with the expected LGM-118A Peacekeeper. These newer missiles were later deployed into modified Minuteman silos.
The Minuteman-II program was economically important to the development of integrated circuits. It was the first mass-produced system to use a computer constructed from integrated circuits (the Autonetics D-37C), and used most of the production of such circuits from 1962 through 1967. The Minuteman-II integrated circuits were diode-transistor logic and diode logic made by Texas Instruments. The other major customer of early integrated circuits was the Apollo Guidance Computer, which had similar weight and ruggedness constraints. The Apollo integrated circuits were resistor-transistor logic made by Fairchild Semiconductor. The Minuteman-II flight computer continued to use rotating magnetic disk for primary storage.
The LGM-30G Minuteman-III program started in 1966, and included several improvements over the previous versions. It was first deployed in 1970. Most modifications related to the final stage and reentry system (RS). The final (third) stage was improved with a new fluid-injected motor, giving finer control than the previous four-nozzle system. Performance improvements realized in Minuteman-III include increased flexibility in reentry vehicle (RV) and penetration aids deployment, increased survivability after a nuclear attack, and increased payload capacity.[1] The missile retains a gimballed inertial guidance system.
Minuteman-III originally contained the following distinguishing features:
CGI videos of the Minuteman III Flight Profile are available.
The existing Minuteman III have been further improved over the decades in service.
The Guidance Replacement Program (GRP) replaces the NS20A Missile Guidance Set with the NS50A Missile Guidance Set. The newer system extends the service life of the Minuteman missile beyond the year 2030 by replacing aging parts and assemblies with current, high reliability technology while maintaining the current accuracy performance. The replacement program was completed 25 February 2008.[2]
Beginning in 1998 and continuing through 2009,[7] the Propulsion Replacement Program extends the life and maintains the performance by replacing the old solid propellant boosters (downstages).
The Single Reentry Vehicle (SRV) modification enabled the United States ICBM force to abide by the now-vacated START II treaty requirements by reconfiguring Minuteman-III missiles from three reentry vehicles down to one. Though it was eventually ratified by both parties, START II never entered into force and was essentially superseded by follow-on agreements such as SORT and New START, which do not limit MIRV capability.
Beginning in 2005, Mk-21/W87 RVs from the deactivated Peacekeeper missile will be placed on the Minuteman-III force under the Safety Enhanced Reentry Vehicle (SERV) program. The older W78 currently used is not equipped with important safety features. In addition to adding additional safety features into at least a portion of the future Minuteman-III force, the decision to transfer W87s onto the missile is based on two features that will improve the targeting capabilities of the weapon: more fuzing options which will allow for greater targeting flexibility and the most accurate reentry vehicle available which provides a greater probability of damage to the designated targets. The first SERV-modded Minuteman III was put on alert status at FE Warren AFB, Wyoming, in 2006.
The Minuteman III missile entered service in 1970, with weapon systems upgrades included during the production run from 1970 to 1978 to increase accuracy and payload capacity. As of 2008[update], the USAF plans to operate it until at least 2030.[2][3]
The LGM-118A Peacekeeper (MX) ICBM, which was to have replaced the Minuteman, was retired in 2005 as part of START II.[8]
A total of 450 LGM-30G missiles are emplaced at F.E. Warren Air Force Base, Wyoming (90th Missile Wing), Minot Air Force Base, North Dakota (91st Missile Wing), and Malmstrom Air Force Base, Montana (341st Missile Wing). All Minuteman I and II have been retired. The United States prefers to keep its MIRV deterrent on submarine-launched Trident Nuclear Missiles[9]
Minuteman III missiles are regularly tested with launches from Vandenberg Air Force Base. The most recent launch was of an unarmed Minuteman III missile from Vandenberg Air Force Base, Calif., which was safely terminated in flight over the Pacific Ocean in the early morning hours of July 28th, 2011.
Controllers observed an anomaly during the last portion of the mission, prompting them to terminate the test early for safety reasons. An anomaly is any unexpected event during the test.
A launch analysis group was formed to investigate. The LAG included members from the 576th Flight Test Squadron, 30th Space Wing safety office, Air Force Nuclear Weapons Center and Northrop Grumman, among other organizations.
The current Minuteman III configuration has a reliable test and evaluation track record, with 22 of 24 fully successful flight tests. The last test to be terminated by mission controllers occurred in 1998.
The 576th FLTS, at Vandenberg AFB, Calif., is responsible for planning, preparing, conducting and assessing ICBM ground and flight tests.
Prior to the July test flight, the most recent was just before 6:40 AM on June 22, 2011. The unarmed missile traveled 4,200 miles meeting its target in the Marshall Islands. Defense officials will use the data collected from the launch to ensure the readiness and capability of the Intercontinental Ballistic Missile Fleet.
Previous to that, the most recent launch from California's Vandenberg Air Force Base was on September 17, 2010, sent a single re-entry test vehicle into suborbital space on a flight that soared some 5,300 miles (8,530 km) across the Pacific Ocean, successfully landing on target about 200 miles (322 km) southwest of Guam.[10][11]
The Minuteman Missile National Historic Site in South Dakota preserves a Launch Control Facility (D-01) and a launch facility (D-09) under the control of the National Park Service.
Footage of Minuteman III ICBM test launches have been featured in several theatrical films and television movies where missile launch footage is needed. The Department of Defense film released for use was mainly drawn from Vandenberg Air Force Base test shots in 1966, including from a "salvo launch" (more than one ICBM launched simultaneously).
Theatrically released films using the footage include (most notably), the 1978 film Superman (which features the "twin shot"), and more extensively, the 1977 nuclear war film Damnation Alley. The made for TV film The Day After also features the same footage, although the first stage of flight is completed via special effects. Terminator 3 uses computer generated images of Minuteman missiles launching from the Plains on Judgment Day. Also features in Eagle Strike, by Anthony Horowitz, in which fictional power-crazed multimillionaire Damian Cray orders their release from Air Force One. In the film WarGames a failed Minuteman launch simulation exercise caused by a conflicted launch control officer is the impetus for the conversion of the missiles to full automatic control by the computer system that Mathew Broderick's character later hacks into.
While the silo-based Minuteman was in development, the United States Air Force released details about a rail-based counterpart. On October 12, 1959, details on the system, called the “Mobile Minuteman,” were released to the public. The system used the United States railroad network to help increase the system's survivability during nuclear attack. A performance test, code named Operation Big Star, was conducted from June 20 to August 27, 1960 at Hill Air Force Base, Utah. The United States Air Force then activated the 4062nd Mobile Missile Wing on December 1, 1960. The wing was to have three missile train squadrons, each with ten trains and each train carrying three missiles (30 missiles per squadron). Lack of support by the Kennedy Administration killed the Mobile Minuteman Program; on December 1, 1961, the Department of Defense deleted the three mobile missile squadrons from its budget. The USAF officially deactivated the 4062nd Mobile Missile Wing on February 20, 1962.
The dreams of a rail-based missile system were kept alive through the LGM-118A Peacekeeper Rail Garrison and the Soviet Union’s SS-24 Scalpel rail-based ICBM.
On 24 Oct 1974, the Space and Missile Systems Organization successfully conducted a Air Mobile Feasibility Test where a C-5A Galaxy aircraft air dropped the 86,000-pound missile from 20,000 feet over the Pacific Ocean. The missile descended to 8,000 feet before its rocket engine fired. The 10-second engine burn carried the missile to 20,000 feet again before it dropped into the ocean. The test proved the feasibility of launching an intercontinental ballistic missile from the air. Operational deployment was discarded due to engineering and security difficulties, though the capability was used as a negotiating point in the Strategic Arms Limitation Talks.[13][14]
An additional part of the National Command Authority communication relay system was called the Emergency Rocket Communication System (ERCS). Specially designed rockets called BLUE SCOUT carried radio-transmitting payloads high above the continental United States, to relay messages to units within line-of-sight. In the event of a nuclear attack, ERCS payloads would relay preprogrammed messages giving the “go-order” to SAC units. BLUE SCOUT launch sites were located at Wisner, West Point and Tekamah, Nebraska. These locations were vital for ERCS effectiveness due to their centralized position in the US, within range of all missile complexes. Later ERCS configurations were placed on the top of modified Minuteman-II ICBMs (LGM-30Fs) under the control of the 510th Strategic Missile Squadron located at Whiteman Air Force Base, Missouri.
The Minuteman ERCS may have been assigned the designation LEM-70A.[15]
The U.S. Air Force has considered using some decommissioned Minuteman missiles in a satellite launching role. These missiles would be stored in silos, for launch upon short notice. The payload would be variable, and would have the ability to be replaced quickly. This would allow a surge capability in times of emergency.
During the 1980s, surplus Minuteman missiles were used to power the Conestoga rocket produced by Space Services Inc. of America. It was the first privately developed rocket, but only saw three flights and was discontinued due to a lack of business. More recently, converted Minuteman missiles have been used to power the Minotaur line of rockets produced by Orbital Sciences.
L-3 Communications is currently using SR-19 SRBs, Minuteman II Second Stage Solid Rocket Boosters, as delivery vehicles for a range of different re-entry vehicles as targets for the THAAD and ASIP interceptor missile programs as well as radar testing.
United States: The United States Air Force has been the only operator of the Minuteman ICBM weapons system, currently with three operational wings and one test squadron operating the LGM-30G. The active inventory in FY 2009 is 450 missiles and 45 Missile Alert Facilities (MAF)
The basic tactical unit of a Minuteman wing is the squadron, consisting of five flights. Each flight consists of ten unmanned launch facilities (LFs) which are remotely controlled by a manned launch control center (LCC). The five flights are interconnected and status from any LF may be monitored by any of the five LCCs. Each LF is located at least three nautical miles (5.6 km) from any LCC. Control does not extend outside the squadron (thus the 319th Missile Squadron’s five LCCs cannot control the 320th Missile Squadron’s 50 LFs even though they are part of the same Space Launch Wing). Each Minuteman wing is assisted logistically by a nearby Missile Support Base (MSB).
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