Editing Submarine-launched ballistic missile (section)

==History==
===Origins===
The first practical design of a [[submarine]]-based launch platform was developed by the Germans near the end of [[World War II]] involving a launch tube which contained a [[V-2 rocket|V-2 ballistic missile]] variant and was towed behind a submarine, known by the code-name [[V-2 rocket#Unfulfilled plans|''Prüfstand XII'']]. The war ended before it could be tested, but the engineers who had worked on it were taken to work for the United States ([[Operation Paperclip]]) and for the Soviet Union on their SLBM programs. These and other early SLBM systems required vessels to be surfaced when they fired missiles, but launch systems were adapted to allow [[underwater]] launching in the 1950-1960s. A converted [[Project 611]] (Zulu-IV class) submarine launched the world's first SLBM, an [[R-11FM]] (SS-N-1 Scud-A, naval variant of the SS-1 [[Scud]]) on 16 September 1955.<ref name="Wade R-11">{{cite web |url=http://www.astronautix.com/lvs/r11.htm |archive-url=https://web.archive.org/web/20020309175348/http://www.astronautix.com/lvs/r11.htm |url-status=dead |archive-date=9 March 2002 |title=R-11 |access-date=23 April 2011 |last=Wade |first=Mark |publisher=[[Encyclopedia Astronautica]]}}</ref> Five additional Project V611 and AV611 (Zulu-V class) submarines became the world's first operational [[ballistic missile]] submarines (SSBs) with two R-11FM missiles each, entering service in 1956–57.<ref>{{cite web|url=http://russianships.info/eng/submarines/project_611.htm|title=Large submarines – Project 611|website=russianships.info}}</ref>

The [[United States Navy]] initially worked on a sea-based variant of the [[US Army]] [[PGM-19 Jupiter|Jupiter]] [[intermediate-range ballistic missile]], projecting four of the large, liquid-fueled missiles per submarine.<ref name="Friedman, pp. 192–195">Friedman, pp. 192–195</ref> Rear Admiral [[William Raborn|W. F. "Red" Raborn]] headed a Special Project Office to develop Jupiter for the Navy, beginning in late 1955.<ref name="Friedman, pp. 192–195"/><ref name="heroicrelics.org"/> However, at the [[Project Nobska]] submarine warfare conference in 1956, physicist [[Edward Teller]] stated that a physically small one-megaton [[warhead]] could be produced for the relatively small, solid-fueled [[Polaris missile]],<ref>{{cite book | last = Teller | first = Edward | title = Memoirs: A Twentieth Century Journey in Science and Politics | publisher = Perseus Publishing | year = 2001 | location = Cambridge, Massachusetts | pages = [https://archive.org/details/memoirstwentieth0000tell/page/420 420–421] | url = https://archive.org/details/memoirstwentieth0000tell/page/420 | isbn = 0-7382-0532-X | url-access = registration }}</ref> and this prompted the Navy to leave the Jupiter program in December of that year. Soon [[Chief of Naval Operations]] Admiral [[Arleigh Burke]] concentrated all Navy strategic research on [[UGM-27 Polaris|Polaris]], still under Admiral Raborn's Special Project Office.<ref name="heroicrelics.org">{{cite web|url=http://heroicrelics.org/info/jupiter/jupiter-hist.html|title=History of the Jupiter Missile System|website=heroicrelics.org}}</ref> All US SLBMs have been solid-fueled while all [[Soviet Union|Soviet]] and Russian SLBMs have been liquid-fueled except for the Russian [[RSM-56 Bulava]], which entered service in 2014.

[[File:Polaris AX (AX-1) on pad LC-25A CCAFS - 1958-09-24.jpg|thumb|[[Polaris missile|Polaris A-1]] on launch pad LC-25A in Cape Canaveral]]
The world's first operational nuclear-powered [[ballistic missile submarine]] (SSBN) was {{USS|George Washington|SSBN-598}} with 16 [[Polaris missile|Polaris A-1]] missiles, which entered service in December 1959 and conducted the first SSBN deterrent patrol November 1960 – January 1961.<ref>Friedman, p. 196</ref> ''George Washington'' also conducted the first successful submerged SLBM launch with a Polaris A-1 on 20 July 1960.<ref>{{citation |url=http://www.flightglobal.com/pdfarchive/view/1963/1963%20-%201949.html |title=Missiles 1963 |journal=[[Flight International]] |date=7 November 1963 |page=752}}</ref> Fifty-two days later, the Soviet Union made its first successful underwater launch of a submarine ballistic missile in the White Sea, on 10 September 1960 from the same converted [[Project 611]] ([[NATO reporting name]] Zulu-IV class) submarine that first launched the R-11FM.<ref name=NiZ>{{cite web |url=http://www.nkj.ru/archive/articles/10079/ |title=Start razreshaju (in Russian) |access-date=23 April 2011 |last=Dygalo|first=V.A. |date=December 1999 |publisher=[[Nauka i Zhizn']]}}</ref> The Soviets were only a year behind the US with their first SSBN, the [[Soviet submarine K-19|ill-fated K-19]] of [[Hotel-class submarine|Project 658]] (Hotel class), commissioned in November 1960. However, the Hotel class carried only three [[R-13 (missile)|R-13 missiles]] (NATO reporting name SS-N-4) each and had to surface and raise the missile to launch.<ref>{{cite web|url=http://russianships.info/eng/submarines/project_658.htm|title=Nuclear-powered ballistic missile submarines – Project 658|website=russianships.info}}</ref> Submerged launch was not an operational capability for the Soviets until 1963, when the [[R-21 (missile)|R-21 missile]] (SS-N-5) was first backfitted to Project 658 (Hotel class) and [[Golf-class submarine|Project 629]] (Golf class) submarines.<ref name="Gardiner and Chumbley, pp. 355–357">Gardiner and Chumbley, pp. 355–357</ref> The Soviet Union was able to beat the U.S. in launching and testing the first SLBM with a live nuclear warhead, an [[R-13 (missile)|R-13]] that detonated in the [[Novaya Zemlya]] Test Range in the Arctic Ocean, doing so on 20 October 1961,<ref>{{cite book |author1=Polmar, Norman |author2=White, Michael |title=Project Azorian: The CIA and the Raising of the K-129 |publisher=Naval Institute Press |year=2010 |page=21 |isbn=978-1-59114-690-2}}</ref> just ten days before the gigantic 50&nbsp;Mt [[Tsar Bomba]]'s detonation in the same general area. The United States eventually conducted a similar test in the Pacific Ocean on 6 May 1962, with a Polaris A-2 launched from {{USS|Ethan Allen|SSBN-608}} as part of the [[nuclear test]] series [[Operation Dominic]]. The first Soviet SSBN with 16 missiles was the [[Yankee-class submarine|Project 667A]] (Yankee class), which first entered service in 1967 with 32 boats completed by 1974.<ref>Gardiner and Chumbley, p. 403</ref><ref>{{cite web|url=http://russianships.info/eng/submarines/project_667a.htm|title=Nuclear-powered ballistic missile submarines – Project 667A|website=russianships.info}}</ref> By the time the first Yankee was commissioned the US had built 41 SSBNs, nicknamed the "[[41 for Freedom]]".<ref>Gardiner and Chumbley, pp. 610–613</ref><ref name="Polmar American Submarine, p. 133">Polmar American Submarine, p. 133</ref>
[[File:Snle-snle-ng-svg.svg|thumb|French [[M45 SLBM]] and [[M51 SLBM]] in cross-section of a submarine.]]

===Deployment and further development===
The short range of the early SLBMs dictated basing and deployment locations. By the late 1960s the Polaris A-3 was deployed on all US SSBNs with a range of {{convert|4600|km|nmi}}, a great improvement on the {{convert|1900|km|nmi}} range of Polaris A-1.  The A-3 also had three warheads that landed in a pattern around a single target.<ref>Friedman, pp. 199–200</ref><ref>Polmar American Submarine, pp. 131–133</ref> The Yankee class was initially equipped with the [[R-27 Zyb]] missile (SS-N-6) with a range of {{convert|2400|km|nmi}}. The US was much more fortunate in its basing arrangements than the Soviets. Thanks to [[NATO]] and the US possession of [[Guam]], US SSBNs were permanently forward deployed at Advanced Refit Sites in [[Holy Loch]], Scotland, [[Naval Station Rota|Rota, Spain]], and Guam by the middle 1960s, resulting in short transit times to patrol areas near the Soviet Union. The SSBN facilities at the Advanced Refit Sites were austere, with only a [[submarine tender]] and [[floating dry dock]]. Converted merchant ships [[hull classification symbol|designated T-AKs]] ([[Military Sealift Command]] cargo ships) were provided to ferry missiles and supplies to the sites. With two rotating crews per boat, about one-third of the total US force could be in a patrol area at any time. The Soviet bases, in [[Severomorsk]] (near [[Murmansk]])  for the [[Arctic Ocean|Arctic]]-[[Atlantic Ocean|Atlantic]] theater in [[Petropavlovsk-Kamchatsky]] for the [[Pacific Ocean|Pacific]] theater, required their SSBNs to make a long transit (e.g., through NATO-monitored waters in the Atlantic) to their mid-ocean patrol areas to hold the continental United States ([[CONUS]]) at risk. This resulted in only a small percentage of the Soviet force occupying patrol areas at any time, and was a great motivation for longer-range Soviet SLBMs, which would allow them to patrol close to their bases, in areas sometimes referred to as "deep bastions". These missiles were the [[R-29 Vysota]] series (SS-N-8, SS-N-18, SS-N-23), equipped on [[Delta-class submarine|Projects 667B, 667BD, 667BDR, and 667BDRM]] (Delta-I through Delta-IV classes).<ref name="Gardiner and Chumbley, pp. 355–357"/> The SS-N-8, with a range of {{convert|7700|km|nmi}}, entered service on the first Delta-I boat in 1972, before the Yankee class was even completed. A total of 43 Delta-class boats of all types entered service 1972–90, with the SS-N-18 on the Delta III class and the [[R-29RM Shtil]] (SS-N-23) on the Delta IV class.<ref>{{cite web|url=http://russianships.info/eng/submarines/project_667b.htm|title=Nuclear-powered ballistic missile submarines – Project 667B|website=russianships.info}}</ref><ref>{{cite web|url=http://russianships.info/eng/submarines/project_667bd.htm|title=Nuclear-powered ballistic missile submarines – Project 667BD|website=russianships.info}}</ref><ref>{{cite web|url=http://russianships.info/eng/submarines/project_667bdr.htm|title=Nuclear-powered ballistic missile submarines – Project 667BDR|website=russianships.info}}</ref><ref>{{cite web|url=http://russianships.info/eng/submarines/project_667bdrm.htm|title=Nuclear-powered ballistic missile submarines – Project 667BDRM|website=russianships.info}}</ref> The new missiles had increased range and eventually multiple independently targetable reentry vehicles ([[MIRV]]), multiple warheads that could each hit a different target.<ref name="Gardiner and Chumbley, pp. 355–357"/>

===Poseidon and Trident I===
Although the US did not commission any new SSBNs from 1967 through 1981, it did introduce two new SLBMs. Thirty-one of the 41 original US SSBNs were built with larger diameter launch tubes with future missiles in mind. In the early 1970s the [[UGM-73 Poseidon|Poseidon (C-3) missile]] entered service, and those 31 SSBNs were backfitted with it.<ref>Friedman, p. 201</ref> Poseidon offered a massive MIRV capability of up to 14 warheads per missile.<ref name="Polmar American Submarine, p. 133"/> Like the Soviets, the US also desired a longer-range missile that would allow SSBNs to be based in CONUS. In the late 1970s the [[UGM-96 Trident I|Trident I (C-4) missile]] with a range of {{convert|7400|km|nmi}} and eight MIRV warheads was backfitted to 12 of the Poseidon-equipped submarines.<ref>Gardiner and Chumbley, pp. 553–554</ref><ref>Friedman, p. 206</ref><ref>Polmar American Submarine, pp. 133–135</ref> The SSBN facilities (primarily a [[submarine tender]] and [[floating dry dock]]) of the base at Rota, Spain were disestablished and the [[Naval Submarine Base Kings Bay]] in [[Georgia (U.S. state)|Georgia]] was built for the Trident I-equipped force.{{citation needed|date=May 2017}}

===Trident and Typhoon submarines===
[[File:Trident II missile cropped.jpg|right|thumb|A [[Trident II missile]] just after launch.]]
Both the United States and the Soviet Union commissioned larger SSBNs designed for new missiles in 1981. The American large SSBN was the [[Ohio-class submarine|''Ohio'' class]], also called the "Trident submarine", with the largest SSBN armament ever of 24 missiles, initially Trident I but built with much larger tubes for the [[UGM-133 Trident II|Trident II (D-5) missile]], which entered service in 1990.<ref>Friedman, pp. 206–207</ref><ref>Gardiner and Chumbley, p. 554</ref> The entire class was converted to use Trident II by the early 2000s. Trident II offered a range of over {{convert|8000|km|nmi}} with eight larger MIRV warheads than Trident I. When the {{USS|Ohio|SSBN-726}} commenced sea trials in 1980, two of the first ten US SSBNs had their missiles removed to comply with SALT treaty requirements; the remaining eight were converted to attack submarines (SSN) by the end of 1982. These were all in the Pacific, and the Guam SSBN base was disestablished; the first several ''Ohio''-class boats used new Trident facilities at [[Naval Submarine Base Bangor]], [[Washington (state)|Washington]]. Eighteen ''Ohio''-class boats were commissioned by 1997,<ref>Gardiner and Chumbley, p. 613</ref> four of which were converted as cruise missile submarines (SSGN) in the 2000s to comply with [[START I]] treaty requirements. The Soviet large SSBN was the [[Typhoon-class submarine|Project 941 Akula]], famous as the Typhoon-class (and not to be confused with the [[Akula-class submarine|Project 971 Shchuka]] [[attack submarine]], called "Akula" by NATO). The Typhoons were the largest submarines ever built at 48,000 tons submerged. They were armed with 20 of the new [[R-39 Rif]] (SS-N-20) missiles with a range of {{convert|8300|km|nmi}} and 10 MIRV warheads. Six Typhoons were commissioned in 1981–89.<ref>{{cite web|url=http://russianships.info/eng/submarines/project_941.htm|title=Nuclear-powered ballistic missile submarines – Project 941|website=russianships.info}}</ref>

===Post-Cold War===
New SSBN construction terminated for over 10 years in Russia and slowed in the US with the [[collapse of the Soviet Union]] and the end of the [[Cold War]] in 1991. The US rapidly decommissioned its remaining 31 older SSBNs, with a few converted to other roles, and the base at Holy Loch was disestablished. Most of the former Soviet SSBN force was gradually scrapped under the provisions of the [[Nunn–Lugar Cooperative Threat Reduction]] agreement through 2012.<ref>{{cite web|url=http://www.dtra.mil/Missions/Verifying.aspx|title=DTRA verification page|access-date=17 April 2015|archive-date=5 September 2015|archive-url=https://web.archive.org/web/20150905130451/http://www.dtra.mil/Missions/Verifying.aspx|url-status=dead}}</ref> By that time the Russian SSBN force stood at six Delta-IVs, three Delta-IIIs, and a lone Typhoon used as a testbed for new missiles (the R-39s unique to the Typhoons were reportedly scrapped in 2012). Upgraded missiles such as the [[R-29RMU Sineva]] (SS-N-23 Sineva) were developed for the Deltas. In 2013 the Russians commissioned the first [[Borei-class submarine]], also called the ''Dolgorukiy'' class after the lead vessel. By 2015 two others had entered service. This class is intended to replace the aging Deltas, and carries 16 solid-fuel [[RSM-56 Bulava]] missiles, with a reported range of {{convert|10000|km|nmi}} and six MIRV warheads. The US is building a [[Ohio Replacement Submarine|replacement for the ''Ohio'' class]]; however, the first of the class wasn't laid down until October 2020.

[[Ballistic missile submarine]]s have been of great strategic importance for the United States, Russia, and other nuclear powers since they entered service in the [[Cold War]], as they can hide from [[reconnaissance satellite]]s and fire their nuclear weapons with virtual impunity. This makes them immune to a [[Pre-emptive nuclear strike|first strike]] directed against nuclear forces, allowing each side to maintain the capability to launch a [[mutually assured destruction|devastating retaliatory strike]], even if all land-based missiles have been destroyed. This relieves each side of the necessity to adopt a [[launch on warning]] posture, with its attendant risk of accidental nuclear war. Additionally, the deployment of highly accurate missiles on ultra-quiet submarines allows an attacker to sneak up close to the enemy coast and launch a missile on a depressed trajectory (a non-optimal [[ballistic trajectory]] which trades off reduced [[throw-weight]] for a faster and lower path, effectively reducing the time between launch and impact), thus opening the possibility of a [[decapitation strike]].{{Citation needed|date=April 2010}}