Editing Nuclear weapon design (section)

===Arbitrarily large multi-staged devices===
The idea of a device which has an arbitrarily large number of Teller-Ulam stages, with each driving a larger radiation-driven implosion than the preceding stage, is frequently suggested,<ref>{{cite book
|last1=Winterberg
|first1=Friedwardt
|title=The Release of Thermonuclear Energy by Inertial Confinement: Ways Towards Ignition
|publisher=World Scientific
|date=2010
|pages=192–193
|isbn=978-9814295918
|url=https://books.google.com/books?id=B7RV_vASz0EC&q=arbitrarily+large+gains%22staged+Teller-Ulam&pg=PA192
|access-date=2020-11-02
|url-status=live
|archive-url=https://web.archive.org/web/20210805053441/https://books.google.com/books?id=B7RV_vASz0EC&q=arbitrarily+large+gains%22staged+Teller-Ulam&pg=PA192
|archive-date=2021-08-05
}}</ref><ref>{{cite book
|last1=Croddy
|first1=Eric A.
|last2=Wirtz
|first2=James J.
|last3=Larsen
|first3=Jeffrey, Eds.
|title=Weapons of Mass Destruction: An Encyclopedia of Worldwide Policy, Technology, and History
|publisher=ABC-CLIO, Inc.
|date=2005
|page=376
|isbn=978-1-85109-490-5
|url=https://books.google.com/books?id=ZzlNgS70OHAC&q=almost+unlimited+yield&pg=RA1-PA376
|access-date=2020-11-02
|url-status=live
|archive-url=https://web.archive.org/web/20210904154854/https://books.google.com/books?id=ZzlNgS70OHAC&q=almost+unlimited+yield&pg=RA1-PA376
|archive-date=2021-09-04
}}</ref> but technically disputed.<ref name=ieri>{{cite web |title=Fission, Fusion and Staging |website=[[IERI]] |url=https://www.ieri.be/fr/publications/ierinews/2011/juillet/fission-fusion-and-staging |access-date=2013-05-22 |url-status=live |archive-url=https://web.archive.org/web/20160305053224/http://ieri.be/fr/publications/ierinews/2011/juillet/fission-fusion-and-staging |archive-date=2016-03-05}}.</ref> There are "well-known sketches and some reasonable-looking calculations in the open literature about two-stage weapons, but no similarly accurate descriptions of true three stage concepts."<ref name=ieri/>

During the mid-1950s through early 1960s, scientists working in the weapons laboratories of the United States investigated weapons concepts as large as 1,000&nbsp;megatons,<ref>[https://nsarchive2.gwu.edu/nukevault/ebb249/doc09.pdf The Air Force and Strategic Deterrence 1951–1960. USAF historical division Liaison Office by George F. Lemmer 1967, p. 13. Formerly restricted data] {{webarchive |url=https://web.archive.org/web/20140617080527/http://www2.gwu.edu/~nsarchiv/nukevault/ebb249/doc09.pdf |date=June 17, 2014}}.</ref> and [[Edward Teller]] announced the design of a 10,000-megaton weapon code-named [[Sundial (weapon)|SUNDIAL]] at a meeting of the General Advisory Committee of the Atomic Energy Commission.<ref>{{cite web|title=In Search of a Bigger Boom|url=https://blog.nuclearsecrecy.com/2012/09/12/in-search-of-a-bigger-boom/|last=Wellerstein|first=Alex|date=12 September 2012}}</ref> Much of the information about these efforts remains classified,<ref>{{cite web |title=2013 FOIA Log |url=https://documents.theblackvault.com/documents/foia/FOIA%2014-00108-H.pdf |access-date=2014-10-06 |url-status=live |archive-url=https://web.archive.org/web/20160304063659/http://documents.theblackvault.com/documents/foia/FOIA%2014-00108-H.pdf |archive-date=2016-03-04}}</ref><ref>{{cite web |title=Case No. FIC-15-0005 |url=https://www.energy.gov/sites/prod/files/2016/04/f30/FIC-15-0005.pdf |access-date=2016-10-25 |url-status=live |archive-url=https://web.archive.org/web/20161025114419/http://energy.gov/sites/prod/files/2016/04/f30/FIC-15-0005.pdf |archive-date=2016-10-25}}</ref> but such "gigaton" range weapons do not appear to have made it beyond theoretical investigations.

While both the US and Soviet Union investigated (and in the case of the Soviets, tested) "very high yield" (e.g. 50 to 100-megaton) weapons designs in the 1950s and early 1960s,<ref>{{cite web|url=https://thebulletin.org/2021/11/the-untold-story-of-the-worlds-biggest-nuclear-bomb/|title=An Unearthly Spectacle: The Untold Story of the World's Biggest Bomb|last=Wellerstein|first=Alex|publisher=Bulletin of the Atomic Scientists|date=29 October 2021}}</ref> these appear to represent the upper-limit of Cold War weapon yields pursued seriously, and were so physically heavy and massive that they could not be carried entirely within the bomb bays of the largest bombers. Cold War warhead development trends from the mid-1960s onward, and especially after the [[Limited Test Ban Treaty]], instead resulted in highly-compact warheads with yields in the range from hundreds of kilotons to the low megatons that gave greater options for deliverability.

Following the concern caused by the estimated gigaton scale of the 1994 [[Comet Shoemaker-Levy 9]] impacts on the planet [[Jupiter]], in a 1995 meeting at [[Lawrence Livermore National Laboratory]] (LLNL), [[Edward Teller]] proposed to a collective of U.S. and Russian ex-[[Cold War]] weapons designers that they collaborate on designing a 1,000-megaton [[asteroid impact avoidance#Nuclear explosive device|nuclear explosive device for diverting extinction-class asteroids]] (10+ km in diameter), which would be employed in the event that one of these asteroids were on an impact trajectory with Earth.<ref>{{cite web |title=A new use for nuclear weapons: hunting rogue asteroids A persistent campaign by weapons designers to develop a nuclear defense against extraterrestrial rocks slowly wins government support 2013 |website=Center for Public Integrity |date=2013-10-16 |url=https://publicintegrity.org/national-security/a-new-use-for-nuclear-weapons-hunting-rogue-asteroids/ |access-date=7 October 2014 |url-status=live |archive-url=https://web.archive.org/web/20160320055111/http://www.publicintegrity.org/2013/10/16/13547/new-use-nuclear-weapons-hunting-rogue-asteroids |archive-date=2016-03-20}}</ref><ref>{{cite web |title=The mother of all bombs would sit in wait in an orbitary platform |author=Jason Mick |date=October 17, 2013 |url=http://www.dailytech.com/Russia+US+Eye+Teamup+to+Build+Massive+Nuke+to+Save+Planet+from+an+Asteroid/article33569.htm |url-status=dead |archive-url=https://web.archive.org/web/20141009190305/http://www.dailytech.com/Russia+US+Eye+Teamup+to+Build+Massive+Nuke+to+Save+Planet+from+an+Asteroid/article33569.htm#sthash.rQvVzS6m.dpuf |archive-date=October 9, 2014}}</ref><ref>[https://web.archive.org/web/20150909023233/https://e-reports-ext.llnl.gov/pdf/232015.pdf planetary defense workshop LLNL 1995]</ref>