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{{Short description|1952 American nuclear bomb test}}
{{Use mdy dates|date=October 2023}} {{Use American English|date=October 2023}}
{{Infobox Nuclear weapons test
 |name                = Ivy Mike
 |picture             = IvyMikeGIFColorCorrected.gif
 |picture_description = Detonation and subsequent [[mushroom cloud]] of the ''"Mike"'' shot (in fast motion).
 |country             = United States<br>Marshall Islands
 |test_series         = [[Operation Ivy]]
 |test_site           = [[Enewetak]], Trust Territory of the Pacific Islands
 |date                = {{Start date and age|1952|11|01|p=yes|br=yes}} 
 |test_type           = [[Nuclear weapons testing#Types|Atmospheric]]
 |yield               = 10.4 [[TNT equivalent|megatons of TNT]]
 |previous_test       = [[Operation Tumbler–Snapper|Tumbler–Snapper How]]
 |next_test           = [[Ivy King]]
}}

'''Ivy Mike''' was the [[code name|codename]] given to the first full-scale{{NoteTag|The [[Greenhouse George]] device in 1951 was the first weapon to use thermonuclear fusion.}} test of a [[Thermonuclear weapon|thermonuclear device]], in which a significant fraction of the explosive [[nuclear weapon yield|yield]] comes from [[nuclear fusion]].<ref name="first">{{cite web |title=Operation Greenhouse – 1951 |url=http://www.myatomiclife.com/1951---op-greenhouse.html |website=Atomic Shadows  |access-date=9 January 2020}}</ref><ref>The first small-scale thermonuclear test was the [[Operation Greenhouse#George|George explosion]] of Operation Greenhouse.</ref><ref name=LT_6>{{citation| publisher=Department of Energy, Nevada Operations Office| date=December 1, 2000| title=United States Nuclear Tests: July 1945 through September 1992| type=DOE/NV-209 REV15| location=Las Vegas, NV| url=http://www.nv.doe.gov/library/publications/historical/DOENV_209_REV15.pdf| access-date=December 18, 2013| url-status=dead| archive-url=https://web.archive.org/web/20100615231826/http://www.nv.doe.gov/library/publications/historical/DOENV_209_REV15.pdf| archive-date=June 15, 2010}}</ref>
Ivy Mike was detonated on November 1, 1952, by the [[United States]] on the island of [[Elugelab]] in [[Enewetak Atoll]], in the now independent  island nation of the [[Marshall Islands]], as part of [[Operation Ivy]]. It was the first full test of the [[Teller–Ulam design]], a [[Nuclear weapon design#Two-stage thermonuclear weapons|staged]] fusion device.<ref name="Wellerstein">{{cite magazine |last1=Wellerstein |first1=Alex |title=A Hydrogen Bomb by Any Other Name |magazine=The New Yorker |date=January 8, 2016 |url=https://www.newyorker.com/tech/annals-of-technology/a-hydrogen-bomb-by-any-other-name |access-date=19 January 2020}}</ref>

Due to its physical size and fusion fuel type ([[cryogenic]] liquid [[deuterium]]),  the "Mike" device was not suitable for use as a deliverable weapon. It was intended as a "technically conservative" [[proof of concept]] experiment to validate the concepts used for multi-[[TNT equivalent|megaton]] detonations.<ref name="Wellerstein"/>

Samples from the explosion had traces of the isotopes [[plutonium-246]], [[plutonium-244]], and the predicted elements [[einsteinium]] and [[fermium]].<ref name="Distillations"/>

==Schedule==
Beginning with the [[History of the Teller–Ulam design|Teller–Ulam]] breakthrough in March 1951, there was steady progress made on the issues involved in a thermonuclear explosion and there were additional resources devoted to staging, and political pressure towards seeing, an actual test of a hydrogen bomb.<ref name="bernstein">{{cite journal | title=Crossing the Rubicon: A Missed Opportunity to Stop the H-Bomb? | author-first=Barton J. | author-last=Bernstein | journal=International Security | volume=14 | issue=2 | date=Fall 1987 | pages=132–160 | doi=10.2307/2538857 | jstor=2538857 | s2cid=154778522 }}</ref>{{rp|137–139}} A date within 1952 seemed feasible.<ref name="atomic-shield"/>{{rp|556}} In October 1951 physicist [[Edward Teller]] pushed for July 1952 as a target date for a first test, but project head [[Marshall Holloway]] thought October 1952, a year out, was more realistic given how much engineering and fabrication work the test would take and given the need to avoid the summer monsoon season in the Marshall Islands.<ref name="Rhodes"/>{{rp|page=482}} On June 30, 1952, [[United States Atomic Energy Commission]] chair [[Gordon Dean (lawyer)|Gordon Dean]] showed President [[Harry S. Truman]] a model of what the Ivy Mike device would look like; the test was set for November 1, 1952.<ref name="atomic-shield"/>{{rp|590}}

One attempt to significantly delay the test, or not hold it at all, was made by the [[State Department Panel of Consultants on Disarmament]], chaired by [[J. Robert Oppenheimer]], who felt that avoiding a test might forestall the development of a catastrophic new weapon and open the way for new arms agreements between the United States and the [[Soviet Union]].<ref name="bernstein"/>{{rp|139–142}} The panel lacked political allies in Washington, however, and no test delay was made on this account.<ref name="bernstein"/>{{rp|145–148}}

There was a separate desire voiced for a very short delay in the test, for more political reasons: it was scheduled to take place just a few days before the [[United States presidential election, 1952|1952 presidential election]].<ref name="Rhodes"/>{{rp|page=497}} Truman wanted to keep the thermonuclear test away from partisan politics but had no desire to order a postponement of it himself; however he did make it known that he would be fine if it was delayed past the election due to "technical reasons" being found.<ref name="atomic-shield">{{cite book | author-last = Hewlett | author-first = Richard G. | author2-last = Duncan | author2-first = Francis | title = Atomic Shield, 1947–1952 | volume=2 | series = A History of the United States Atomic Energy Commission | publisher = Pennsylvania State University Press | location = University Park| date = 1969 |url=https://www.energy.gov/sites/prod/files/2013/04/f0/Hewlett%20and%20Duncan%20-%20Atomic%20Shield%20%28complete%29.pdf }}</ref>{{rp|590–591}}<ref name="Rhodes"/>{{rp|pages=497–498}} Atomic Energy Commission member [[Eugene M. Zuckert]] was sent to the Enewetak test site to see if such a reason could be found, but weather considerations – on average there were only a handful of days each month that were suitable for the test – indicated it should go ahead as planned, and in the end no schedule delay took place.<ref name="atomic-shield"/>{{rp|590–592}}<ref name="Rhodes"/>{{rp|page=498}}

==Device design and preparations==
[[Image:Ivy Mike Sausage device.jpg|right|thumb|A view of the "Sausage" device casing, with its instrumentation and cryogenic equipment attached. The long pipes were for measurement purposes; their function was to transmit the first radiation from the "primary" and "secondary" stages (known as "Teller light") to instruments just as the device was detonated, before being destroyed in the explosion. The man seated lower right shows scale.]]
The {{convert|82|ST|MT|sigfig=2|abbr=off|adj=on}}  "Mike" device was a building that resembled a factory rather than a weapon.<ref name="Parsons">{{cite book |last1=Parsons |first1=Keith M. |last2=Zaballa |first2=Robert A. |title=Bombing the Marshall Islands: A Cold War Tragedy |date=2017 |publisher=Cambridge University Press |url=https://books.google.com/books?id=mQQvDwAAQBAJ&pg=PA41|pages=41–46|isbn=9781108508742 }}</ref> It has been reported that Soviet engineers derisively referred to "Mike" as a "thermonuclear installation".<ref name="Brotherhood_2002"/>{{rp|page=391}}

The device was designed by [[Richard Garwin]], a student of [[Enrico Fermi]], on the suggestion of [[Edward Teller]]. It had been decided that nothing other than a full-scale test would validate the idea of the [[Teller-Ulam design]]. Garwin was instructed to use very conservative estimates when designing the test, and told that it need not be small and light enough to be deployed by air.<ref name="Teller"/>{{rp|page=327}}

Liquid [[deuterium]] was chosen as the fuel for the fusion reaction because its use simplified the experiment from a physicist's point of view, and made the results easier to analyze. From an engineering point of view, its use necessitated the development of previously unknown technologies to handle the difficult material, which had to be stored at extremely low temperatures, near [[absolute zero]].<ref name="Parsons"/>{{rp|pages=41–42}} A large cryogenics plant was built to produce liquid hydrogen (used for cooling the device) and deuterium (fuel for the test).  A 3000&nbsp;kW power plant was also constructed for the cryogenics facility.<ref name="Parsons"/>{{rp|page=44}}

The device that was developed for testing the Teller-Ulam design became known as a "Sausage" design:<ref name="Parsons"/>{{rp|page=43}}

* At its center was a cylindrical insulated [[steel]] Dewar ([[vacuum flask]]) or [[cryostat]]. This tank, almost {{convert|7|ft|m|sigfig=2|abbr=on}} across and more than {{convert|20|ft|m|sigfig=2|abbr=on}} high,<ref name="Parsons"/>{{rp|page=43}} had walls almost {{convert|30|cm|ft|sigfig=2|abbr=on}} thick.<ref name="CTBTO">{{cite web |title=1 November 1952 – Ivy Mike |url=https://www.ctbto.org/specials/testing-times/1-november-1952-ivy-mike |website= [[Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization]] |access-date=2021-11-10 | df =dmy-all}}</ref> It weighed approximately {{convert|54|ST|MT|sigfig=2|abbr=off}}.<ref name="AtomicPhotography"/> It was capable of holding {{convert|1000|liters|USgal|sigfig=2|abbr=on}} of liquid deuterium, cooled to near-absolute zero.<ref>{{cite web |title=Deuterium|page=8 |url=https://cpb-us-w2.wpmucdn.com/wonecks.net/dist/4/1630/files/2016/03/Deuterium-Article-1aqpg12.pdf}}</ref><ref name="Reichhardt">{{cite news |last1=Reichhardt |first1=Tony |title=The First Hydrogen Bomb |url=https://www.airspacemag.com/daily-planet/first-hydrogen-bomb-180967074/ |access-date=22 January 2020 |work=Air & Space |date=November 2, 2017}}</ref> The [[cryogenic]] deuterium provided the fuel for the "secondary" ([[nuclear fusion|fusion]]) stage of the explosion.<ref name="Parsons"/>{{rp|page=43}}
* At one end of the cylindrical Dewar flask was a [[Mark 5 nuclear bomb|TX-5]]<ref name="swordsoarIII" />{{rp|page=66}} regular [[nuclear fission|fission]] bomb (not boosted<ref name="swordsoarIII"/>{{rp|page=43}}). The TX-5 bomb was used to create the conditions needed to initiate the fusion reaction. This "primary" fission stage was nested inside the radiation case at the upper section of the device, and was not in physical contact with the "secondary" fusion stage. The TX-5 did not require refrigeration.<ref name="swordsoarIII"/>{{rp|page=43}}<ref name="Parsons"/>{{rp|pages=43–44}}
* Running down the center of the Dewar flask within the secondary was a cylindrical rod of [[plutonium]] within a chamber of tritium gas. This "fission sparkplug" was imploded by x-rays from the primary detonation. That provided a source of outward-moving pressure inside the deuterium and increased conditions for the fusion reaction.<ref name="Parsons"/>{{rp|pages=43–44}}
* Surrounding the assembly was a {{convert|5|ST|MT|sigfig=2|abbr=off|adj=on}} natural [[uranium]] "tamper". The exterior of the tamper was lined with sheets of [[lead]] and [[polyethylene]], forming a [[radiation]] channel to conduct [[X-rays]] from the "primary" to the "secondary" stage. As laid out in the [[Teller-Ulam design]], the function of the X-rays was to compress the "secondary" with tamper/pusher [[ablation]], foam plasma pressure and [[radiation pressure]]. This process increases the density and temperature of the deuterium to the level needed to sustain a thermonuclear reaction, and compress the "sparkplug" to a [[Critical mass (nuclear)|supercritical mass]] – inducing the "sparkplug" to undergo nuclear fission and to thereby start a fusion reaction in the surrounding deuterium fuel.<ref name="Parsons"/>{{rp|pages=43–44}}

[[File:Ivy Mike shot cab.jpg|thumb|right|The Ivy Mike shot cab and signal tower.]]
The entire "Mike" device (including cryogenic equipment) weighed {{convert|82|ST|MT|sigfig=2|abbr=off}}. It was housed in a large corrugated-aluminum building, called the shot cab, which was {{convert|88|ft|m|sigfig=2|abbr=on}} long,
{{convert|46|ft|m|sigfig=2|abbr=on}} wide, and 
{{convert|61|ft|m|sigfig=2|abbr=on}} high, with a 
{{convert|300|ft|m|sigfig=2|abbr=on|adj=on}} signal tower.  Television and radio signals were used to communicate with a control room on {{USS|Estes}} where the firing party was located.<ref name="Parsons"/>{{rp|pages=43–44}}<ref name="Gladeck"/>{{rp|page=42}}

It was set up on the Pacific island of [[Elugelab]], part of the [[Enewetak]] atoll.  Elugelab was connected to the islands of Dridrilbwij (Teiteir), Bokaidrikdrik (Bogairikk), and Boken (Bogon) by a {{convert|9000|ft|km|sigfig=2|abbr=on|adj=on}}
artificial causeway. Atop the causeway was an [[aluminum]]-sheathed [[plywood]] tube filled with [[helium]] [[ballonet]]s, referred to as a [[Nuclear weapon design#Light pipes|Krause-Ogle box]].<ref name="Gladeck"/>{{rp|page=34}} 
This allowed [[gamma ray|gamma]] and [[neutron]] radiation to pass uninhibited to instruments in an unmanned detection station, Station 202, on Boken Island. From there signals were sent to recording equipment at Station 200, also housed in a bunker on Boken Island. Personnel returned to Boken Island after the test to recover the recording equipment.<ref name="Gladeck"/>{{rp|pages=136, 138}}

In total, 9,350 military and 2,300 civilian personnel were involved in the "Mike" shot.<ref name="Gladeck"/>{{rp|page=2|quote=The total number of personnel involved in the task force was nearly 11,650, of which 9,350 were military and 2,300 were civilians.  Most of the civilians and over 6,600 of the military personnel operated from Enewetak Atoll and from task force ships that were based there.  Most of the remaining military were Air Force personnel who were based at Kwajalein, 360 mi (667 km) southeast of
Enewetak.}} The operation involved the cooperation of the United States Army, Navy, Air Force and intelligence services.  The [[USS Curtiss (AV-4)|USS ''Curtiss'']] brought components from the United States to  Elugelab for assembly.  Work was completed on October 31, at 5.00 p.m.  Within an hour, personnel were evacuated in preparation for the blast.<ref name="Parsons"/>{{rp|pages=43–44}}

==Detonation==
[[File:IvyMikeFireball.gif|thumb|Ivy-''Mike'' fireball]]
[[Image:Ivy Mike - Elugelab pt1.jpg|thumb|Enewetak Atoll, '''before''' "Mike" shot. Note island of Elugelab on left.]]
[[Image:Ivy Mike - Elugelab pt2.jpg|thumb|Enewetak Atoll, '''after''' "Mike" shot. The crater is on the left.]]

The test was carried out on 1 November 1952 at 07:15 local time (19:15 on 31 October, [[Greenwich Mean Time]]). It produced a yield of {{convert|10.4|MtonTNT|lk=on}}.<ref name="Rowberry">{{cite news |last1=Rowberry |first1=Ariana |title=Castle Bravo: The Largest U.S. Nuclear Explosion |url=https://www.brookings.edu/blog/up-front/2014/02/27/castle-bravo-the-largest-u-s-nuclear-explosion |access-date=9 January 2020 |work=Brookings |date=February 27, 2014}}</ref><ref name="Fabry" /> {{percentage|77|100}} of the final yield came from [[fast fission]] of the uranium tamper, which produced large amounts of radioactive [[nuclear fallout|fallout]].{{citation needed|date=January 2020}}

The fireball created by the explosion had a maximum radius of {{convert|2.9|to|3.3|km|sigfig=2|abbr=on}}.<ref name="Walker">{{Cite web | last=Walker | first=John | author-link=John Walker (programmer) | title=Nuclear Bomb Effects Computer | publisher=Fourmilab | date=June 2005 | access-date=2009-11-22 | url=http://www.fourmilab.ch/cgi-bin/Bombcalc?yield=10400&yunit=1&range=5&runit=0.62137119&rotate=310&imsize=800 }}
</ref><ref name="John">{{Cite web | last=Walker | first=John | author-link=John Walker (programmer) | title=Nuclear Bomb Effects Computer Rev. Ed. 1962, Based on Data from The Effects of Nuclear Weapons, Rev. Ed., 'The maximum fireball radius presented on the computer is an average between that for air and surface bursts. Thus, the fireball radius for a surface burst is 13 percent larger than that indicated and for an air burst, 13 percent smaller.'| publisher=Fourmilab | date=June 2005 | access-date=2009-11-22 | url=http://www.fourmilab.ch/bombcalc/instructions.html}}</ref><ref>{{cite web |url=http://www.remm.nlm.gov/RemmMockup_files/radiationlethality.jpg |title=Mock up |publisher=Remm.nlm.gov |access-date=2013-11-30 |archive-date=2013-06-07 |archive-url=https://web.archive.org/web/20130607091341/http://www.remm.nlm.gov/RemmMockup_files/radiationlethality.jpg |url-status=dead }}</ref> The maximum radius was reached several seconds after the detonation, during which the hot fireball lifted up due to [[buoyancy]]. While still relatively close to the ground, the fireball had yet to reach its maximum dimensions and was thus approximately {{convert|5.2|km|sigfig=2|abbr=on}} wide. The [[mushroom cloud]] rose to an altitude of {{convert|17|km|ft|sigfig=2|abbr=on}} in less than 90 seconds. One minute later it had reached {{convert|33|km|ft|sigfig=3|abbr=on}}, before stabilizing at {{convert|41|km|ft|sigfig=3|abbr=on}} with the top eventually spreading out to a diameter of {{convert|161|km|sigfig=3|abbr=on}} with a stem {{convert|32|km|sigfig=2|abbr=on}} wide.<ref name="Blades">{{cite book |last1=Blades |first1=David M. Blades |last2=Siracusa |first2=Joseph M. |title=A History of U.S. Nuclear Testing and Its Influence on Nuclear Thought, 1945–1963 |date=2014 |publisher=Rowman & Littlefield |page=54 |url=https://books.google.com/books?id=tKEXBgAAQBAJ&pg=PA54 |access-date=21 January 2020|isbn=9781442232013 }}</ref>

The blast created a crater {{convert|1.9|km|ft|sigfig=3|abbr=on}} in diameter and {{convert|50|m|ft|sigfig=3|abbr=on}} deep where Elugelab had once been;<ref>{{cite web |title=Operation Ivy 1952 - Enewetak Atoll, Marshall Islands|date= 14 May 1999 |url=http://nuclearweaponarchive.org/Usa/Tests/Ivy.html |website=Nuclear Weapon Archive |access-date=9 January 2020}}</ref> the blast and water waves from the explosion (some waves up to {{convert|6|m|ft|sigfig=1|abbr=on}} high) stripped the test islands clean of vegetation, as observed by a helicopter survey within 60 minutes after the test, by which time the mushroom cloud and steam were blown away. Radioactive coral debris fell upon ships positioned {{convert|56|km|mi|sigfig=2|abbr=on}} away, and the immediate area around the atoll was heavily contaminated.<ref name="Froehlich">{{cite journal |last1=Froehlich |first1=M.B. |last2=Chan |first2=W.Y. |last3=Tims |first3=S.G. |last4=Fallon |first4=S.J. |last5=Fifield |first5=L.K. |title=Time-resolved record of 236U and 239, 240Pu isotopes from a coral growing during the nuclear testing program at Enewetak Atoll (Marshall Islands) |journal=Journal of Environmental Radioactivity |date=December 2016 |volume=165 |pages=197–205 |doi=10.1016/j.jenvrad.2016.09.015|pmid=27764678 |doi-access=free }}</ref><ref name="Buesseler">{{cite journal |last1=Buesseler |first1=Ken O. |last2=Charette |first2=Matthew A. |last3=Pike |first3=Steven M. |last4=Henderson |first4=Paul B. |last5=Kipp |first5=Lauren E. |title=Lingering radioactivity at the Bikini and Enewetak Atolls |journal=Science of the Total Environment |date=April 2018 |volume=621 |pages=1185–1198 |doi=10.1016/j.scitotenv.2017.10.109|pmid=29096952 |bibcode=2018ScTEn.621.1185B |doi-access=free |hdl=1912/9537 |hdl-access=free }}</ref><ref name="Hughes">{{cite journal |last1=Hughes |first1=Emlyn W. |last2=Molina |first2=Monica Rouco |last3=Abella |first3=Maveric K. I. L. |last4=Nikolić-Hughes |first4=Ivana |last5=Ruderman |first5=Malvin A. |title=Radiation maps of ocean sediment from the Castle Bravo crater |journal=Proceedings of the National Academy of Sciences |date=30 July 2019 |volume=116 |issue=31 |pages=15420–15424 |doi=10.1073/pnas.1903478116 |pmid=31308235 |pmc=6681739 |bibcode=2019PNAS..11615420H |doi-access=free }}</ref>

Close to the fireball, lightning discharges were rapidly triggered.<ref name="Colvin">{{cite journal |last1=Colvin |first1=J. D. |last2=Mitchell |first2=C. K. |last3=Greig |first3=J. R. |last4=Murphy |first4=D. P. |last5=Pechacek |first5=R. E. |last6=Raleigh |first6=M. |title=An empirical study of the nuclear explosion-induced lightning seen on IVY-MIKE |journal=Journal of Geophysical Research |date=1987 |volume=92 |issue=D5 |page=5696 |doi=10.1029/JD092iD05p05696 |bibcode=1987JGR....92.5696C }}</ref>
The entire shot was documented by the filmmakers of [[Lookout Mountain Air Force Station|Lookout Mountain studios]].<ref name="Chamberlain">{{cite news |last1=Chamberlain |first1=Craig |title=New book tells story of secret Hollywood studio that shaped the nuclear age |date=January 14, 2019 |work=Illinois News Bureau |url=https://news.illinois.edu/view/6367/739553}}</ref> A [[post-production]] explosion sound was [[overdubbed]] over what was a completely silent detonation from the vantage point of the camera, with the blast wave sound only arriving later, as akin to [[thunder]], with the exact time depending on its distance.<ref>{{cite web|url=http://ocw.nd.edu/physics/nuclear-warfare/notes/lecture-14#mechanical-shock |title=Nuclear Warfare Lecture 14 by Professor Grant J. Matthews of University of Notre Dame OpenCourseWare. Mechanical Shock velocity equation |url-status=dead |archive-url=https://web.archive.org/web/20131219010502/http://ocw.nd.edu/physics/nuclear-warfare/notes/lecture-14 |archive-date=2013-12-19 }}</ref> The film was also accompanied by powerful, [[Richard Wagner|Wagner]]-esque music featured on many test films of that period and was hosted by actor [[Reed Hadley]].  A private screening was given to President [[Dwight D. Eisenhower]] who had succeeded President [[Harry S. Truman]] in January 1953.<ref name="Weart">{{cite book |last1=Weart |first1=Spencer |title=The Rise of Nuclear Fear |date=2012 |publisher=Harvard University Press |page=80 |url=https://books.google.com/books?id=9KBD-YrGOVkC&pg=PA80|isbn=9780674065062 }}</ref>{{rp|80}} In 1954, the film was released to the public after censoring, and was shown on commercial television channels.<ref name="Weart"/>{{rp|183}}

[[Edward Teller]], perhaps the most ardent supporter of the development of the hydrogen bomb, was in [[Berkeley, California]], at the time of the shot.<ref name="Time">{{cite magazine |title=The Atom: The Road Beyond Elugelab |url=https://content.time.com/time/subscriber/article/0,33009,823289,00.html |access-date=21 January 2020 |magazine=Time |issue=15|volume=63|page= 23 |date=April 12, 1954}}</ref> He was able to receive first notice that the test was successful by observing a [[seismometer]], which picked up the [[shock wave]] that traveled through the earth from the [[Pacific Proving Grounds]].<ref name="Axelrod">{{cite book |last1=Axelrod |first1=Alan |title=The Real History of the Cold War: A New Look at the Past |date=2009 |publisher=Sterling |page=[https://archive.org/details/realhistoryofcol0000axel/page/156 156] |url=https://archive.org/details/realhistoryofcol0000axel |url-access=registration |access-date=21 January 2020|isbn=9781402763021 }}</ref><ref name="Rhodes">{{Cite Q | Q105755363 | last1 = Rhodes | first1 = Richard | author-link1 = Richard Rhodes | df = dmy-all | via = [[Internet Archive]] }}</ref>{{rp|pages=777–778}} In his memoirs, Teller wrote that he immediately sent an unclassified telegram to [[Elizabeth Riddle Graves|Dr. Elizabeth "Diz" Graves]], the head of the rump project remaining at [[Los Alamos National Laboratory|Los Alamos]] during the shot.  The telegram contained only the words "It's a boy," which came hours earlier than any other word from Enewetak.<ref name="Ford">{{cite book|title=Geons, Black Holes, and Quantum Foam: A Life in Physics |first1=Kenneth |last1=Ford |first2=John Archibald |last2=Wheeler |page=227 |publisher=W.W. Norton & Co. |date=2010 |url=https://books.google.com/books?id=zGFkK2tTXPsC&q=elizabeth+graves+physicist&pg=PA227 |access-date=2013-12-21|isbn=9780393079487 }}</ref><ref name="Teller">{{cite book |last1=Teller |first1=Edward |last2=Schoolery |first2=Judith |title=Memoirs: A Twentieth Century Journey In Science And Politics |date=2009 |publisher=Perseus Publishing |location=Cambridge, MA |url=https://books.google.com/books?id=n82xMo-BI8QC&q=%22It%27s+a+boy%2C%22|isbn=9780786751709 }}</ref>{{rp|352}}

==Scientific discoveries==
[[Image:IvyMikeCloudTrinity&Beyond.jpg|thumb|''Mike'' [[mushroom cloud]].]]
An hour after the bomb was detonated, U.S. Air Force pilots took off from Enewetak Island to fly into the atomic cloud and take samples. Pilots had to monitor extra readouts and displays while "piloting under unusual, dangerous, and difficult conditions” including heat, radiation, unpredictable winds and flying debris. "Red Flight" Leader [[Virgil K. Meroney]] flew into the stem of the explosion first. In five minutes, he had gathered all the samples he could, and exited. Next Bob Hagan and Jimmy Robinson entered the cloud. Robinson hit an area of severe turbulence, entering a spin and barely retaining consciousness. He regained control of his plane at 20,000 feet, but the electromagnetic storm had disrupted his instruments. In rain and poor visibility, without working instruments, Hagan and Robinson were unable to find the KB-29 tanker aircraft to refuel.<ref name="Distillations"/><ref name="Gladeck"/>{{rp|96}} They attempted to return to the field at Enewetak. Hagan, out of fuel, made a successful [[deadstick landing|dead-stick landing]] on the runway. Robinson's [[F-84 Thunderjet]] crashed and sank 3.5 miles short of the island. Robinson's body was never recovered.<ref name="Distillations"/><ref name="F-84G-5-RE">{{cite web |title=F-84G-5-RE Thunderjet Serial Number 51-1040 |url=https://www.pacificwrecks.com/aircraft/f-84/51-1040.html |website=Pacific Wrecks |access-date=9 January 2020}}</ref><ref name="Wolverton">{{cite journal |last1=Wolverton |first1=Mark |title=Into the Mushroom Cloud Most pilots would head away from a thermonuclear explosion |journal=Air & Space Magazine|publisher=Smithsonian |date=2009 |issue=August |url=https://www.airspacemag.com/history-of-flight/into-the-mushroom-cloud-35152524/ |access-date=9 January 2020}}</ref>

Fuel tanks on the airplane's wings had been modified to scoop up and filter passing debris. The filters from the surviving planes were sealed in lead and sent to [[Los Alamos, New Mexico]] for analysis. Radioactive and contaminated with [[calcium carbonate]], the "Mike" samples were extremely difficult to handle. Scientists at Los Alamos found traces in them of isotopes [[plutonium-246]] and [[plutonium-244]].<ref name="Distillations"/>

[[Al Ghiorso]] at the [[University of California, Berkeley]] speculated that the filters might also contain atoms that had transformed, through radioactive decay, into the predicted but undiscovered elements 99 and 100.  Ghiorso, [[Stanley Gerald Thompson]] and [[Glenn Seaborg]] obtained half a filter paper from the Ivy Mike test. They were able to detect the existence of the elements [[einsteinium]] and [[fermium]], which had been produced by intensely concentrated neutron flux about the detonation site. The discovery was kept secret for several years, but the team was eventually given credit. In 1955 the two new elements were named in honor of [[Albert Einstein]] and [[Enrico Fermi]].<ref name="Distillations">{{cite web |first1= Kit |last1=Chapman |title= Element Hunting in a Nuclear Storm   |date= January 14, 2020  |url=https://www.sciencehistory.org/distillations/element-hunting-in-a-nuclear-storm |website=Distillations |publisher= [[Science History Institute]] |access-date=January 14, 2020}}</ref><ref name="KAPL">{{cite book |author=Knolls Atomic Power Laboratory (KAPL) |title=Nuclides and Isotopes – Chart of the Nuclides |date=2010 |publisher=Bechtel Marine Propulsion Corporation |location=Schenectady, NY |edition=17th}}</ref><ref name="Nagy">{{cite book |last1=Nagy |first1=Sandor |title=Radiochemistry and Nuclear Chemistry |volume= I |year=2009 |publisher=EOLSS Publications |pages=91–92 |url=https://books.google.com/books?id=VbO2CwAAQBAJ&pg=PA91 |access-date=21 January 2020|isbn=9781848261266 }}</ref>

==Related tests==
A simplified and lightened bomb version (the [[Mark 16 nuclear bomb|EC-16]]) was prepared and scheduled to be tested in operation [[Castle Yankee]], as a backup in case the non-cryogenic "Shrimp" fusion device (tested in [[Castle Bravo]]) failed to work; that test was canceled when the Bravo device was tested successfully, making the cryogenic designs obsolete.{{citation needed|date=January 2020}}

==Gallery==
<gallery class="center" widths="220">
File:Ivy Mike (Eniwetok-Atoll - 31. Oktober 1952).jpg
File:Ivy Mike 002.jpg
File:Ivy Mike fallout map.png|[[Nuclear fallout]] map of ''Mike'' test.
File:Ivy Mike fireball.jpg|''Mike'' fireball.
File:Enewetak Atoll 2005-09-01, EO-1 bands 10-8-2-1.png|''Mike'' test crater, relative to [[Enewetak Atoll]].
File:Ivy Mike overshooting top.jpg|''Mike'' [[mushroom cloud]] central stem's updraft tropopause overshoots. 
</gallery>

==See also==
* [[History of nuclear weapons]]
* [[Operation Castle]]
* [[RDS-6s]] – first Soviet thermonuclear test, coming less than a year later

== Notes ==
{{reflist|group=note}}

==References==
{{reflist|30em|refs=

<ref name="Brotherhood_2002">{{cite book | last1 = Herken | first1 = Gregg | author-link1 = Gregg Herken | date = 2002 | chapter = Notes for Chapter Fourteen 'A Bad Business Now Threatening'| chapter-url = https://archive.org/details/brotherhoodofbom0000herk_v0x5/page/391/mode/1up | chapter-url-access = registration | title = Brotherhood of the Bomb: The Tangled Lives and Loyalties of Robert Oppenheimer, Ernest Lawrence and Edward Teller | url = https://archive.org/details/brotherhoodofbom0000herk_v0x5 | url-access = registration | language = en-us | edition = 1st |  publisher = [[Henry Holt and Company]] | isbn = 978-0-80-506588-6 | lccn = 2002017219 | oclc = 890256840 | ol = OL7932650M | access-date = 2021-11-10 | via = [[Internet Archive]] | quote = Mike was meant to be a proof-of-principle test of radiation implosion, and not a deliverable bomb.  Housed in a six-story building, weighing more than 80 tons, the cryogenically-cooled device was later described disdainfully by the Russians as a "thermonuclear installation." | quote-page = 391 | df = dmy-all}}</ref>

<ref name="Gladeck">{{cite tech report | last1 = Gladeck | first1 = F. R. | last2 = Hallowell | first2 = J. H. | last3 = Martin |first3 = E. J.  | last4 = McMullan  | first4 = F. W. | last5 = Miller | first5 = R. H. | last6 = Pozega | first6 = R. | last7 = Rogers | first7 = W. E. | last8 = Rowland | first8 = R. H. | last9 = Shelton | first9 = C. F. | last10 = Berkhouse |first10 = L. | last11 = Davis |first11 = S. | last12 = Doyle |first12 = M. K.  | last13 = Jones |first13 = C. B. | display-authors = 5 | others =  | name-list-style =  | date = 1982-12-01 | title = Operation Ivy: 1952 | number = DNA 6036F | institution = [[Defense Threat Reduction Agency|Defense Nuclear Agency]]  | url = https://www.dtra.mil/Portals/61/Documents/NTPR/2-Hist_Rpt_Atm/1952_DNA_6036F.pdf | url-status = live | format = pdf | language = en-us | location = [[Washington, D.C.]] | page =  | pages =  | archive-url = https://web.archive.org/web/20210822185725/https://www.dtra.mil/Portals/61/Documents/NTPR/2-Hist_Rpt_Atm/1952_DNA_6036F.pdf | archive-date = 2021-08-22 | access-date = 2021-11-10 | quote =  | quote-page =  | quote-pages =  | df = dmy-all}}</ref>

<ref name="AtomicPhotography">{{cite journal | date = 2015-07-01 | editor1-last = Dillingham | editor1-first = Clay | title = Atomic Photography: Blasts From The Past | url = https://www.lanl.gov/discover/publications/national-security-science/2015-july/_assets/doc/NSS-july-2015.pdf | journal = National Security Science | language = en-us | publisher = [[Los Alamos National Laboratory]] | volume = 15 | issue = 5 | pages = 16–21 | access-date = 2021-11-10 | df = dmy-all}}</ref>

<ref name="swordsoarIII">{{cite book |first=Chuck |last=Hansen |title=The Swords of Armageddon: U.S. Nuclear Weapons Development Since 1945 |year=2007 |location=Sunnyvale, California |publisher=Chukelea Publications |format=PDF |type=CD-ROM & download available |isbn= 978-0979191503  | oclc = 231585284 |edition=2nd |url=http://www.uscoldwar.com}}</ref>

<ref name="Fabry">{{cite magazine | last1 = Fabry | first1 = Merrill | date = 2015-11-02 | title = What the First H-Bomb Test Looked Like | url = https://time.com/4096424/ivy-mike-history/ | url-access = limited  | url-status = live | format =  | department = History | magazine = [[Time (magazine)|Time]] | language = en | volume = 186 | issue = 16 | issn = 0040-781X | oclc = 1311479 | archive-url = https://web.archive.org/web/20210904052722/https://time.com/4096424/ivy-mike-history/ | archive-date = 2021-09-04 | access-date = 2021-11-10 | quote = At 7:15 a.m. local time on Elugelab Island, Mike was detonated from a control ship 30 m. away. The detonation resulted in a massive explosion, equivalent to 10.4 Megatons of TNT. | df = dmy-all}}</ref>

}}

==Further reading==
{{refbegin}}
*{{cite book | last1 = Hansen | first1 = Chuck | author-link1 = Chuck Hansen | date = 1988-03-20 | title = U.S. Nuclear Weapons: The Secret History | url = https://archive.org/details/usnuclearweapons0000hans | url-access = registration | language = en-us | edition = 1st | publisher = [[Crown Publishing Group|Crown]] | isbn = 978-0517567401 | lccn = 87021995 | oclc = 865554459 | ol = OL2392513M | access-date = 2021-11-10 | via = [[Internet Archive]] | df = dmy-all}}

{{refend}}

==External links==
{{Commons category|Ivy Mike}}
* {{Internet Archive film|id=OperationIVY1952_201501|name=Operation IVY}} – ''formerly classified''.
* [http://webarchive.loc.gov/all/20120206122658/http://www.sonicbomb.com/modules.php?name%3DContent%26pa%3Dshowpage%26pid%3D184 Sonicbomb.com: "Ivy Mike test" video]
* [https://apps.dtic.mil/sti/citations/AD0363641 Technical Photography on Operation Ivy by EG&G] – {{cite web|url= http://www.dtic.mil/get-tr-doc/pdf?AD=AD0363641 |archive-url= https://web.archive.org/web/20150614130131/http://www.dtic.mil/get-tr-doc/pdf?AD=AD0363641 |url-status= dead |archive-date= June 14, 2015 |title=Full Text }}&nbsp;{{small|(5.5 MB)}}

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{{Nuclear weapons tests of the United States}}

[[Category:Explosions in 1952]]
[[Category:Enewetak Atoll nuclear explosive tests]]
[[Category:1952 in military history]]
[[Category:1952 in the environment]]
[[Category:1950s in the Marshall Islands]]
[[Category:1952 in the Trust Territory of the Pacific Islands]]
[[Category:Articles containing video clips]]
[[Category:November 1952 in Oceania]]