Editing Nuclear bunker buster (section)

== Targets and the development of bunker busters ==
[[File:B-61 bomb.jpg|thumb|200px|[[B61 nuclear bomb]]]]
As early as 1944, the Barnes Wallis [[Tallboy bomb]] and subsequent [[Grand Slam bomb|Grand Slam]] weapons were designed to penetrate deeply fortified structures through sheer explosive power. These were not designed to directly penetrate defences, though they could do this (for example, the [[Valentin submarine pens]] had [[ferrous concrete]] roofs {{convert|4.5|m|ft|order=flip}} thick which were penetrated by two Grand Slams on 27 March 1945), but rather to penetrate under the target and explode leaving a [[camouflet]] (cavern) which would undermine foundations of structures above, causing it to collapse, thus negating any possible hardening. The destruction of targets such as the [[V-3 cannon|V3 battery]] at [[Fortress of Mimoyecques|Mimoyecques]] was the first operational use of the Tallboy. One bored through a hillside and exploded in the [[Saumur]] rail tunnel about {{convert|18|m|ft|order=flip|sigfig=1}} below, completely blocking it, and showing that these weapons could destroy any hardened or deeply [[Earthworks (engineering)|excavated]] installation. Modern targeting techniques allied with multiple strikes could perform a similar task.<ref>{{Citation| place = United Kingdom | publisher = Ministry of Defence | title = RAF Bomber Command Grand Slam raids | url = http://www.raf.mod.uk/history/bombercommandgrandslamraids.cfm | archive-url=https://web.archive.org/web/20140226053516/http://www.raf.mod.uk/history/bombercommandgrandslamraids.cfm |archive-date=2014-02-26 |url-status=live}}.</ref><ref>{{Citation | url = http://www.raf.mod.uk/bombercommand/jul44.html | title = RAF Bomber Command Campaign Diary July 1944 | place = UK | contribution = July 1944 | at = (6 July "Mimoyecques V-Weapon Site" photograph shows clearly the camouflet effect) | publisher = Ministry of Defence |archive-url=https://web.archive.org/web/20050514061638/http://www.raf.mod.uk/bombercommand/jul44.html |archive-date=2005-05-14 |url-status=dead}}</ref><ref>{{Citation | url =http://www.raf.mod.uk/history/bombercommandsaumurtunnel9thjune1944.cfm | title = RAF Bomber Command Saumur Tunnel Raid| contribution = Saumur | publisher = Ministry of Defence | place = UK |archive-url=https://web.archive.org/web/20140226011740/http://www.raf.mod.uk/history/bombercommandsaumurtunnel9thjune1944.cfm |archive-date=2014-02-26 |url-status=live}}.</ref>

Development continued, with weapons such as the nuclear [[B61 nuclear bomb|B61]], and conventional thermobaric weapons and [[GBU-28]]. One of the more effective housings, the GBU-28 used its large mass ({{convert|2130|kg|lb|abbr=on|disp=or|order=flip}}) and casing (constructed from barrels of surplus 203&nbsp;mm [[howitzer]]s) to penetrate {{convert|6|m|ft|abbr=off|order=flip}} of concrete, and more than {{convert|30|m|ft|order=flip|sigfig=1}} of earth.<ref>{{Citation | publisher = Rice | url = http://es.rice.edu/projects/Poli378/Gulf/gwtxt_ch6.html#GBU-28 | type = report to Congress | title = The Conduct of the Persian Gulf War | contribution = GBU-28 | archive-url = https://web.archive.org/web/20070202221842/http://es.rice.edu/projects/Poli378/Gulf/gwtxt_ch6.html#GBU-28 | archive-date = 2 February 2007 | url-status = dead | access-date = 14 January 2006 }}.</ref> The B61 Mod 11, which first entered military service after the Cold war had ended, in January 1997, was specifically developed to allow for bunker penetration, and is speculated to have the ability to destroy hardened targets a few hundred feet beneath the earth.<ref>{{Citation | title = USA weapons | publisher = Nuclear weapon archive | url = http://nuclearweaponarchive.org/Usa/Weapons/B61.html | contribution = The B61 (Mk-61) Bomb |archive-url=https://web.archive.org/web/20090227003412/http://nuclearweaponarchive.org/Usa/Weapons/B61.html |archive-date=2009-02-27 |url-status=live}}.</ref>

While penetrations of {{convert|20|to|100|ft|m|0}} were sufficient for some shallow targets, both the [[Soviet Union]] and the United States were creating bunkers buried under huge volumes of soil or reinforced concrete in order to withstand the multi-megaton thermonuclear weapons developed in the 1950s and 1960s. Bunker penetration weapons were initially designed within this [[Cold War]] context. One likely Soviet Union/Russian target, [[Mount Yamantau]], was regarded in the 1990s by Maryland Republican congressman, [[Roscoe Bartlett]], as capable of surviving "half a dozen" repeated nuclear strikes of an unspecified yield, one after the other in a "direct hole".<ref>{{cite web |url=http://viewzone2.com/yamantaux.html |title=Yamantau Whats going on in the Yamantau mountain complex?}}</ref><ref>{{cite web |url=http://www.thelivingmoon.com/45jack_files/03files/Yamantau_Mountain_Complex_Russia.html |title=Secret Bases Russia Yamantau Mountain Complex Beloretsk, Russia}}</ref>

The Russian [[continuity of government]] facility at [[Kosvinsky Mountain]], finished in early 1996, was designed to resist US earth-penetrating warheads and serves a similar role as the American [[Cheyenne Mountain Complex]].<ref>{{cite web|url=http://www.windowonheartland.net/2012/02/russias-top-secret-bases.html |title=WINDOW ON HEARTLAND Geopolitical notes on Eastern Europe, the Caucasus and Central Asia |url-status=dead |archive-url=https://web.archive.org/web/20130424050959/http://www.windowonheartland.net/2012/02/russias-top-secret-bases.html |archive-date=24 April 2013 }}</ref><ref>[http://www.globalsecurity.org/wmd/library/news/russia/1997/bmd970404a.htm  "Moscow builds bunkers against nuclear attack"], by [[Bill Gertz]], ''[[Washington Times]]'', 1 April 1997</ref> The timing of the Kosvinsky completion date is regarded as one explanation for US interest in a new nuclear bunker buster and the declaration of the deployment of the B-61 Mod 11 in 1997. Kosvinsky is protected by about {{convert|300|m|ft|order=flip|sigfig=1}} of [[granite]].<ref>{{cite web |url=http://www.globalsecurity.org/wmd/world/russia/kosvinsky.htm |title=Global Security.org Kosvinsky Mountain, Kos'vinskiy Kamen', Gora, MT 59°31'00"N 59°04'00"E}}</ref>

The weapon was revisited{{dubious|date=May 2014}} after the Cold War during the 2001 [[War in Afghanistan (2001–present)|US invasion of Afghanistan]], and again during the [[2003 invasion of Iraq]]. During the campaign in [[Tora Bora]] in particular, the United States believed that "vast underground complexes," deeply buried, were protecting opposing forces. Such complexes were not found. While a nuclear penetrator (the "Robust Nuclear Earth Penetrator", or "RNEP") was never built, the US [[United States Department of Energy|DOE]] was allotted budget to develop it, and tests were conducted by the US [[Air Force Research Laboratory]]. The RNEP was to use the 1.2&nbsp;megaton [[B83 nuclear bomb|B83]] physics package.<ref>{{cite web |last=Beljac |first=Marco |date=21 September 2006 |title=Does Divine Strake Live On? |url=http://sciencesecurity.livejournal.com/2003.html |website=Science and Global Security}}</ref>

The [[George W. Bush|Bush]] administration removed its request for funding<ref>{{Citation | url = http://news.bbc.co.uk/1/hi/4377446.stm | title = US cancels bunker bomb programme | date = 26 October 2005 | work= BBC |archive-url=https://web.archive.org/web/20140424223521/http://news.bbc.co.uk/2/hi/4377446.stm |archive-date=2014-04-24 |url-status=live}}</ref> of the weapon in October 2005. Additionally, then [[United States Senate|US Senator]] [[Pete Domenici]] announced funding for the nuclear bunker-buster has been dropped from the US [[United States Department of Energy|Department of Energy]]'s 2006 budget at the department's request.<ref>{{Citation  | url=https://news.yahoo.com/s/ap/20051026/ap_on_go_pr_wh/bunker_buster | title=Bush Admin. Drops 'Bunker-Buster' Plan | work=Yahoo! News | date=25 October 2005 | agency=Associated Press | access-date=2014-03-06 | author=Hebert, H. Josef | archive-url=https://web.archive.org/web/20051027195236/http://news.yahoo.com/s/ap/20051026/ap_on_go_pr_wh/bunker_buster | archive-date=2005-10-27}}</ref>

While the project for the RNEP seems to be in fact canceled, [[Jane's Information Group]] speculated in 2005 that work might continue under another name.<ref>{{Citation | archive-url = https://web.archive.org/web/20071022215958/http://janes.com/defence/news/jid/jid051117_1_n.shtml | title = US dumps bunker-buster – or not? | publisher = Jane's | archive-date = 2007-10-22 | url = http://janes.com/defence/news/jid/jid051117_1_n.shtml}}.</ref>

A more recent development (c. 2012) is the [[GBU-57]] Massive Ordnance Penetrator, a {{convert|30000|lb|kg|adj=on}} conventional gravity bomb. The USAF's B-2 Spirit bombers can each carry two such weapons.