Editing LGM-30 Minuteman (section)

=== Minuteman III (LGM-30G) {{anchor|Minuteman-III|LGM-30G|Minuteman-III (LGM-30G)|reason=For wiki redirects}} ===
[[File:Minuteman-3 Museum.jpg|thumb|Minuteman III]]
[[File:Minuteman III diagram.png|thumb|Side view of Minuteman III ICBM]]
[[File:Minuteman_III_RVs.jpg|thumb|[[Airman|Airmen]] work on a Minuteman III's multiple independently-targetable re-entry vehicle (MIRV) system. Current missiles carry a single warhead.]]
:''See also [[W62|W62 warhead]]''
The LGM-30G Minuteman III program started in 1966 and included several improvements over the previous versions. Its first test launch took place on August 16, 1968. 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. The missile retains a [[gimbal]]led [[inertial navigation system]].

Minuteman III originally contained the following distinguishing features:

* Armed with up to three [[W62]] Mk-12 warheads, having a yield of only 170 kilotons TNT, instead of previous [[W56]]'s yield of 1.2 megatons.<ref name="usa-archive" /><ref>{{cite web|title=Minuteman Missile Nuclear Warheads|url=https://minutemanmissile.com/nuclearwarheads.html|access-date=2020-07-21|website=minutemanmissile.com}}</ref><ref>{{cite web|title=The W62 Warhead|url=https://nuclearweaponarchive.org/Usa/Weapons/W62.html|access-date=2020-07-21|website=nuclearweaponarchive.org}}</ref>
* It was the first<ref name="gwu.edu" /> missile equipped with [[multiple independently targetable reentry vehicle]]s (MIRV). A single missile was then able to target three separate locations. This was an improvement from the Minuteman I and Minuteman II models, which were able to carry only one large warhead.
** An RS capable of deploying, in addition to the warheads, [[penetration aid]]s such as [[Chaff (radar countermeasure)|chaff]] and [[decoy]]s.
** Minuteman III introduced in the post-boost-stage ("bus") an additional liquid-fuel propulsion system rocket engine (PSRE) that is used to slightly adjust the [[trajectory]]. This enables it to dispense decoys or – with MIRV – dispense individual RVs to separate targets. For the PSRE it uses the bipropellant Rocketdyne RS-14 engine.
* The Hercules M57 third stage of Minuteman I and Minuteman II had thrust termination ports on the sides. These ports, when opened by detonation of shaped charges, reduced the chamber pressure so abruptly that the interior flame was blown out. This allowed a precisely timed termination of thrust for targeting accuracy. The larger Minuteman III third-stage motor also has thrust termination ports although the final velocity is determined by PSRE.
* A fixed nozzle with a liquid injection thrust vector control system on the new third-stage motor (similar to the second-stage Minuteman II nozzle) additionally increased range.
* A flight computer (Autonetics [[D37D]]) with larger disk memory and enhanced capability.
** A Honeywell HDC-701 flight computer which employed non-destructive readout [[plated-wire memory]] instead of rotating magnetic disk for primary storage was developed as a backup for the D37D but was never adopted.
** The Guidance Replacement Program, initiated in 1993, replaced the disk-based D37D flight computer with a new one that uses [[radiation hardened|radiation-resistant]] [[semiconductor]] [[RAM]].

The Minuteman III missiles use D-37D computers and complete the 1,000 missile deployment of this system. The initial cost of these computers range from about $139,000 (D-37C) to $250,000 (D-17B).

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

The existing Minuteman III missiles have been further improved over the decades in service, with more than $7 billion spent in the 2010s to upgrade the 450 missiles.<ref name="2012_Pampe" />

==== Specifications ====
The Minuteman III has a length of {{convert|59.9|ft|m|abbr=on|sp=us}},<ref name="FAS_LGM-30-3" /> weighs {{convert|79,432|lb|kg|abbr=on|sp=us}},<ref name="FAS_LGM-30-3" /> an operational range of {{convert|14000|km|abbr=on|sp=us|order=flip}},{{sfn|Sandia Weapon Review: Nuclear Weapon Characteristics Handbook|p=74}} and an accuracy of about {{convert|800|ft|m|abbr=on|sp=us}}.<ref name="1996_dtic" /><ref name="2009_Polmar" />

==== W78 warhead ====
In December 1979 the higher-yield [[W78]] warhead (335–350 kilotons) began replacing a number of the W62s deployed on the Minuteman IIIs.<ref name="NWA20010901" /> These were delivered in the Mark 12A reentry vehicle. A small, unknown number of the previous Mark 12 RVs were retained operationally, however, to maintain a capability to attack more-distant targets in the south-central Asian republics of the [[USSR]] (the Mark 12 RV weighed slightly less than the Mark 12A).

==== Guidance Replacement Program ====
The Guidance Replacement Program replaces the NS20A Missile Guidance Set with the NS50 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.<ref name="irconnect1"/>

==== Propulsion Replacement Program ====
Beginning in 1998 and continuing through 2009,<ref name="2006_ATK" /> the Propulsion Replacement Program extends the life and maintains the performance by replacing the old solid propellant boosters (downstages).

==== Single Reentry Vehicle ====
The Single Reentry Vehicle modification enabled the United States ICBM force to abide by the now-voided [[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 [[Strategic Offensive Reductions Treaty|SORT]] and [[New START]], which do not limit MIRV capability. Minuteman III remains fitted with a single warhead due to the warhead limitations in New START.

==== Safety Enhanced Reentry Vehicle ====
Beginning in 2005, Mk-21/[[W87]] RVs from the deactivated [[LGM-118 Peacekeeper|Peacekeeper]] missile were replaced on the Minuteman III force under the Safety Enhanced Reentry Vehicle (SERV) program. The older [[W78]] did not have many of the safety features of the newer W87, such as [[Insensitive munition|insensitive high explosives]], as well as more advanced safety devices. In addition to implementing these safety features in at least a portion of the future Minuteman III force, the decision to transfer W87s onto the missile was based on two features that improved the targeting capabilities of the weapon: more [[Fuze|fuzing]] options which allowed for greater targeting flexibility, and the most accurate reentry vehicle available, which provided a greater probability of damage to the designated targets.

==== Deployment ====
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|2024|06}}, the USAF plans to operate it until the mid-2030s.<ref name="MMIII_Test" />

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

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 Minuteman II missiles have been retired. The United States prefers to keep its MIRV deterrents on submarine-launched [[Trident Missile|Trident Nuclear Missiles]]<ref name="2019_Navy_Trident" /> In 2014, the Air Force decided to put fifty Minuteman III silos into "warm" unarmed status, taking up half of the 100 slots in America's allowable nuclear reserve. These can be reloaded in the future if necessary.<ref name="2014_Kirstensen_Obama_Weakens_START" />

==== Testing ====
[[File:Minuteman III in silo 1989.jpg|thumb|A Minuteman III missile in its silo]]
Minuteman III missiles are regularly tested with launches from [[Vandenberg Space Force Base]] in order to validate the effectiveness, readiness, and accuracy of the weapon system, as well as to support the system's primary purpose, [[Deterrence theory|nuclear deterrence]].<ref>{{cite news |last=Burns |first=Robert |date=26 February 2016 |title=U.S. continues to test Cold War-era Minuteman missiles |url=http://www.pressherald.com/2016/02/26/u-s-continues-to-test-cold-war-era-minuteman-missiles/ |newspaper=Portland Press Herald |location=Portland, Oregon |access-date=13 August 2016 |archive-url=https://web.archive.org/web/20160825194801/http://www.pressherald.com/2016/02/26/u-s-continues-to-test-cold-war-era-minuteman-missiles/ |archive-date=25 August 2016 |url-status=live }}</ref> The safety features installed on the Minuteman III for each test launch allow the flight controllers to terminate the flight at any time if the systems indicate that its course may take it unsafely over inhabited areas.<ref>{{cite news |author=<!--Staff writer(s); no by-line.--> |title=Minuteman Test Firing Aborted Over Pacific |url=https://www.latimes.com/archives/la-xpm-1985-02-06-mn-4340-story.html |newspaper=Los Angeles Times |location=Los Angeles, California |date=6 February 1985 |access-date=13 August 2016 |archive-url=https://web.archive.org/web/20160827144925/http://articles.latimes.com/1985-02-06/news/mn-4340_1_minuteman-iii |archive-date=27 August 2016 |url-status=live }}</ref> Since these flights are for test purposes only, even terminated flights can send back valuable information to correct a potential problem with the system.

The test of an unarmed Minuteman III failed on November 1, 2023, from Vandenberg Space Force Base, California. The U.S. Air Force said it had blown up the missile over the Pacific Ocean after an anomaly was detected following its launch.<ref>{{cite web | url=https://www.airandspaceforces.com/icbm-test-failure-nuclear-modernization/ | title=ICBM Test Failure Puts Nuclear Modernization Effort into Focus | date=3 November 2023 }}</ref><ref>{{cite web | url=https://www.reuters.com/world/us/us-air-force-blows-up-minuteman-iii-test-flight-after-post-launch-anomaly-2023-11-01/ | title=US Air Force blows up Minuteman III in test flight after post-launch anomaly | work=Reuters }}</ref>

The [[576th Flight Test Squadron]] is responsible for planning, preparing, conducting, and assessing all ICBM ground and flight tests.