LGM-30 Minuteman

LGM-30 Minuteman
Minuteman3launch.jpg
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)

Warhead Nuclear W62, W78, or (2006-) W87

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 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
Silo

The LGM-30 Minuteman is a U.S. nuclear missile, a land-based intercontinental ballistic missile (ICBM). As of 2009, it is the only land-based ICBM in service in the United States. It is complemented by the sea-launched Trident missile SLBM and by nuclear weapons carried by long-range strategic bombers; see current status of United States nuclear weapons.

The “L” 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.

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 planned to keep the missile in service until 2020, but it may be upgraded to stay in service until 2030.

Contents

Current model

A Minuteman III missile in its silo

The current Minuteman force consists of 450 Minuteman III missiles[1] in missile silos around F.E. Warren AFB, Wyoming; Malmstrom AFB, Montana; and Minot AFB, North Dakota.

It is a guided missile with three solid-fuel stages, and in the post-boost stage (“bus”), a liquid-fuel propulsion system rocket engine is used to fine-tune the trajectory of the reentry vehicle and/or dispense individual warheads to separate targets. The missile has a gimballed inertial guidance system.

The third stage has precision shutdown ports which, when opened, reduce the chamber pressure so abruptly that the interior flame is blown out. This allows a more precise trajectory which improves targeting accuracy. The post-boost stage carries, in addition to the warheads, penetration aids such as chaff and decoys.

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 2007, USAF plans are to operate it until 2040.

The LGM-118A Peacekeeper (MX) ICBM, which was to have replaced the Minuteman, was retired in 2005 as part of START II.[2]

Guidance Replacement Program (GRP)

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 2020 by replacing aging parts and assemblies with current, high reliability technology while maintaining the current accuracy performance.

Propulsion Replacement Program (PRP)

Beginning in 1998 and continuing through 2009 [3], the Propulsion Replacement Program extends the life and maintains the performance by replacing the old solid propellant boosters (downstages).

Single Reentry Vehicle (SRV)

The Single Reentry Vehicle (SRV) modification allows the United States ICBM force to abide by START I treaty requirements by reconfiguring Minuteman-III missiles from three reentry vehicles down to one. The Minuteman III was originally designed with the capability of carrying three each of the 330 KT warheads (MIRV), each missile was then able to target 3 separate locations. This was an improvement from the Minuteman I and II models, which were only able to carry 1 larger warhead.

Safety Enhanced Reentry Vehicle (SERV)

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 moded Minuteman III was put on alert status at FE Warren AFB, Wyoming, in 2006.

Organization

Connectivity of 91st SW Missile Field

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 (i.e. The 319th Missile Squadron’s five LCCs cannot control the 320th Missile Squadron’s 50 LFs). Each Minuteman wing is assisted logistically by a nearby Missile Support Base (MSB).

Operator

 United States: The United States Air Force is the only operator of the Minuteman III, with three operational wings and one test squadron operating the LGM-30G. The active inventory in FY 2009 is 450 missiles and 45 launch control centers.

Academic Instruction Units

Active Units

Former Units

History

Minuteman I missile

The Minuteman-I and Minuteman-II were in service from 1960 until 1997. The Minuteman-III was first deployed in 1969 and with the latest upgrades is expected to remain in service through the year 2025.

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 other ICBMs, which used liquid fuels. A crucial innovation in this area was to include a valve to release the booster pressure, and permit effective throttling of the booster.

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.

Minuteman-I (LGM-30A/B or SM-80/HSM-80A)

Autonetics D-17 guidance computer from a Minuteman I missile.

See also W56 Warhead

Deployment

The LGM-30A Minuteman-I was first test-fired on 1 February 1961[12], 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. 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.

Guidance

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).

Minuteman-II (LGM-30F)

  1. See also W56 Warhead
  2. See also W62 Warhead

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, payload 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 antiballistic 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). Performance improvements realized in Minuteman-II include greater range, increased throw weight, improved accuracy and reliability, multiple target selection, and greater penetration capability.

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 LGM-118A, as these latter missiles were introduced 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.

Minuteman-III (LGM-30G)

Side view of Minuteman-III ICBM
Airmen work on a Minuteman III’s Multiple Independently-targetable Re-entry Vehicle (MIRV) system. Current missiles carry a single warhead.

The LGM-30G Minuteman-III program started in 1966, and included several improvements that distinguish it from the LGM-30F Minuteman-II. Most modifications related to the final stage and reentry system (RS), with the third stage 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.

A Honeywell HDC-701 flight computer which employs NDRO (non-destructive read out) plated wire memory instead of rotating magnetic disk for primary storage was developed as a backup for the D37D, but was never adopted. The D37D remained the flight computer for the Minuteman III until the guidance system was replaced on the Guidance Replacement Program (GRP).

The Guidance Replacement Program (GRP), initiated in 1993, flight computer uses radiation-resistant semiconductor RAM.

Minuteman-III MIRV launch sequence:
1. The missile launches out of its silo by firing its 1st stage boost motor (A).
2. About 60 seconds after launch, the 1st stage drops off and the 2nd stage motor (B) ignites. The missile shroud (E) is ejected.
3. About 120 seconds after launch, the 3rd stage motor (C) ignites and separates from the 2nd stage.
4. About 180 seconds after launch, 3rd stage thrust terminates and the Post-Boost Vehicle (D) separates from the rocket.
5. The Post-Boost Vehicle maneuvers itself and prepares for re-entry vehicle (RV) deployment.
6. The RVs, as well as decoys and chaff, are deployed during backaway.
7. The RVs and chaff re-enter the atmosphere at high speeds and are armed in flight.
8. The nuclear warheads detonate, either as air bursts or ground bursts.

Current Deployment

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.

Testing

Minuteman III missiles are regularly tested with launches from Vandenberg Air Force Base. The most recent launch, successfully targeting the Kwajalein Atoll 4,200 miles downrange with three unarmed re-entry vehicles, was conducted 2009-06-29.[13]

Related Programs

Influences

Recreation Room, Launch Control Facility, Warren Air Force Base near Raymer, Colorado

The author Thomas Pynchon worked as a technical writer for the field support unit for the Minuteman missile, something that is probably reflected in the narrative of his novels The Crying of Lot 49 and Gravity’s Rainbow.

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.

Appearances in Media

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.

Other Roles

Mobile Minuteman program[14]

Mobile Minuteman Artist Conception

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 thoughts 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.

Emergency Rocket Communications System (ERCS)

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 (sometimes called RED SPY) 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.

Satellite launching role

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.

Ground and Air Launch Targets

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.

Minuteman chronology[15]

Photo gallery

See also

Comparable aircraft

Related lists

References

  • The Boeing Corporation (1973) Technical Order 21M-LGM30G-1-1: Minuteman Weapon System Description. Seattle: Boeing Aerospace. Contains basic weapon descriptions.
  • The Boeing Corporation (1973) Technical Order 21M-LGM30G-1-22: Minuteman Weapon System Operations. Seattle: Boeing Aerospace. Operators Manual.
  • The Boeing Corporation (1994) Technical Order 21M-LGM30G-2-1-7: Organizational Maintenance Control, Minuteman Weapon System. Seattle: Boeing Aerospace. Operators Manual.
  • Lloyd, A. (2000) Cold War Legacy: A Tribute to the Strategic Air Command: 1946-1992. New York: Turner Publishing.
  • Neal, Roy. (1962) Ace in the Hole: The Story of the Minuteman Missile. New York: Doubleday & Company. Library of Congress Catalog Card Number 62-7665.
  • Zuckerman, E. (1984) The Day after World War III. New York: Viking Press.

External links