View source for Operation Upshot–Knothole

{{Short description|Series of 1950s US nuclear tests}}
{{see also|List of nuclear weapons tests of the United States}}
{{Use mdy dates|date=November 2018}}
{{Infobox nuclear weapons test
 |name                = Operation Upshot–Knothole
 |picture             = File:UpshotKnotholeGrable.gif
 |picture_description = Upshot-Knothole ''Grable'', 15 kilotons.
 |country             = United States
 |test_site           = {{plainlist|
*NTS Areas 5, 11, Frenchman Flat
*NTS, Areas 1-4, 6-10, Yucca Flat}}
 |period              = 1953
 |number_of_tests     = 11
 |test_type           = free air drop, gun deployed, tower
 |max_yield           = {{convert|61|ktTNT|lk=in}}
 |previous_series     = [[Operation Ivy]]
 |next_series         = [[Operation Castle]]
}}
{{GeoGroup|article=Operation Upshot–Knothole}}

'''Operation Upshot–Knothole''' was a series of eleven nuclear test shots conducted in 1953 at the [[Nevada Test Site]]. It followed ''[[Operation Ivy]]'' and preceded ''[[Operation Castle]]''.

Over 21,000 soldiers took part in the ground exercise [[Desert Rock V]] in conjunction with the ''[[Upshot-Knothole Grable]]'' shot.<ref>{{Cite report| url=http://www.dtra.mil/documents/ntpr/factsheets/Upshot_Knothole.pdf |title=Operation UPSHOT-KNOTHOLE Fact Sheet |publisher=Defense Threat Reduction Agency }}{{webarchive|url=https://web.archive.org/web/20130218012525/http://www.dtra.mil/documents/ntpr/factsheets/Upshot_Knothole.pdf |date=February 18, 2013}}</ref> ''Grable'' was a 280mm Artillery Fired Atomic Projectile (AFAP) shell fired from the "[[M65 atomic cannon|Atomic Cannon]]" and was viewed by a number of high-ranking military officials.

The test series was notable as containing the first time an AFAP shell was fired (''GRABLE'' Shot), the first two shots (both [[Fizzle (nuclear test)|fizzles]]) by University of California Radiation Laboratory—Livermore (now [[Lawrence Livermore National Laboratory]]), and for testing out some of the thermonuclear components that would be used for the massive thermonuclear series of [[Operation Castle]]. One primary device ([[RACER IV|RACER]]) was tested in thermonuclear system mockup assemblies of [[Mark 14 nuclear bomb|TX-14]], [[Mark 16 nuclear bomb|TX-16]], and [[Mark 17 nuclear bomb|TX-17]]/[[Mark 24 nuclear bomb|TX-24]], to examine and evaluate the behaviour of radiation cases and the compression of the secondary geometries by the primary's x-rays prior to full-scale testing during [[Operation Castle|Castle]].<ref name="swordsoarIII">{{cite book |author-link=Chuck Hansen |first=Chuck |last=Hansen |title=Swords of Armageddon |volume=III |date=1995 |url=http://www.uscoldwar.com |access-date=December 28, 2016}}</ref>{{refpage|192}} Following RACER's dodgy performance, the COBRA primary was used in the emergency capability [[Mark 14 nuclear bomb|ALARM CLOCK]], [[Mark 16 nuclear bomb|JUGHEAD]], [[Mark 17 nuclear bomb|RUNT I]], [[Mark 24 nuclear bomb|RUNT II]] thermonuclear devices, as well as in the [[Castle Bravo|SHRIMP]] device.<ref name="swordsoarIII" />{{refpage|200}} RACER IV (as redesigned and proof-tested in the [[Upshot-Knothole Simon|Simon]] test) was employed as primary for the ZOMBIE,<ref name="swordsoarIII" />{{refpage|200}} RAMROD and [[Castle Koon|MORGENSTERN]]<ref name="swordsoarIII" />{{refpage|318}} devices.

Navy scientist Pauline Silvia conducted experiments during the tests, and would later be profiled in the 2010 documentary [[Atomic Mom]].<ref>{{cite web|url=https://www.international.ucla.edu/asia/article/115394|title='Atomic Mom' Filmmaker Reveals Secret Stories of the Bomb|author=Olvera, Lorena|publisher=UCLA Asia Pacific Center|accessdate=2024-12-06}}</ref>

==Nuclear tests==
===Annie===
Planned yield for '''Annie''' was {{convert|15|ktTNT}}, actual yield based on radiochemical analysis was {{convert|16.2|ktTNT}}.<ref>{{Cite report| publisher = NAVAL AIR MATERIAL CENTER PHILADELPHIAPA| author1 = Rogin, Leo| author2 = DuPont, Alden C| author3 = Weeber, Christian G| title = Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight| accessdate = 2023-09-30| url = https://apps.dtic.mil/sti/citations/ADA387404|ref={{harvid|Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight}}|page=25}}</ref>

===Nancy===
Planned yield for '''Nancy''' was {{convert|40|ktTNT}}, actual yield based on radiochemical analysis was {{convert|24.5|ktTNT}}.{{sfn|Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight|p=28}}

===Simon===
Planned yield for '''Simon''' was {{convert|33|ktTNT}}, actual yield based on radiochemical analysis was {{convert|43.4|ktTNT}}.{{sfn|Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight|p=32}}

===Harry===
Planned yield for '''Harry''' was {{convert|37|ktTNT}}, actual yield based on radiochemical analysis was {{convert|27|ktTNT}}.{{sfn|Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight|p=36}}

===Encore===
Planned yield for '''Encore''' was {{convert|31|ktTNT}}, actual yield based on radiochemical analysis was {{convert|26|ktTNT}}.{{sfn|Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight|p=41}}

==List of tests==

{| class="wikitable sortable"
 |+ United States' Upshot-Knothole series tests and detonations
 |- style="vertical-align: top;"
 !style="background:#ffdead;" | Name<ref group=note>The US, France and Great Britain have code-named their test events, while the USSR and China did not, and therefore have only test numbers (with some exceptions &ndash; Soviet peaceful explosions were named). Word translations into English in parentheses unless the name is a proper noun. A dash followed by a number indicates a member of a salvo event. The US also sometimes named the individual explosions in such a salvo test, which results in "name1 &ndash; 1(with name2)". If test is canceled or aborted, then the row data like date and location discloses the intended plans, where known.</ref>
 !style="background:#efefef;" | Date time ([[Universal Time|UT]])
 !style="background:#ffdead;" | Local [[Time Zone|time zone]]<ref group=note>To convert the UT time into standard local, add the number of hours in parentheses to the UT time; for local daylight saving time, add one additional hour. If the result is earlier than 00:00, add 24 hours and subtract 1 from the day; if it is 24:00 or later, subtract 24 hours and add 1 to the day. Historical time zone data obtained from the [[tz database|IANA time zone database]].</ref><ref>{{cite web| title=Time Zone Historical Database| publisher=iana.com| url=http://www.ietf.org/timezones/| access-date=March 8, 2014}}</ref>
 !style="background:#efefef;" | [[List of nuclear test sites|Location]]<ref group=note>Rough place name and a latitude/longitude reference; for rocket-carried tests, the launch location is specified before the detonation location, if known. Some locations are extremely accurate; others (like airdrops and space blasts) may be quite inaccurate. "~" indicates a likely pro-forma rough location, shared with other tests in that same area.</ref>
 !style="background:#ffdead;" | [[Elevation]] + height<ref group=note>Elevation is the ground level at the point directly below the explosion relative to sea level; height is the additional distance added or subtracted by tower, balloon, shaft, tunnel, air drop or other contrivance. For rocket bursts the ground level is "N/A". In some cases it is not clear if the height is absolute or relative to ground, for example, ''Plumbbob/John''. No number or units indicates the value is unknown, while "0" means zero. Sorting on this column is by elevation and height added together.</ref>
 !style="background:#efefef;" | Delivery<ref group=note>Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, and barge are all disallowed by the [[Partial Nuclear Test Ban Treaty]]. Sealed shaft and tunnel are underground, and remained useful under the PTBT. Intentional cratering tests are borderline; they occurred under the treaty, were sometimes protested, and generally overlooked if the test was declared to be a peaceful use.</ref><br />Purpose<ref group=note>Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.</ref>
 !style="background:#efefef;" | [[List of nuclear weapons|Device]]<ref group=note>Designations for test items where known, "?" indicates some uncertainty about the preceding value, nicknames for particular devices in quotes. This category of information is often not officially disclosed.</ref>
 !style="background:#ffdead;" | [[Nuclear weapon yield|Yield]]<ref group=note>Estimated energy yield in [[TNT equivalent|tons, kilotons, and megatons]]. A ton of TNT equivalent is defined as 4.184&nbsp;gigajoules (1&nbsp;gigacalorie).</ref>
 !style="background:#efefef;" class="unsortable" | [[Nuclear fallout|Fallout]]<ref group=note>Radioactive emission to the atmosphere aside from prompt neutrons, where known. The measured species is only iodine-131 if mentioned, otherwise it is all species. No entry means unknown, probably none if underground and "all" if not; otherwise notation for whether measured on the site only or off the site, where known, and the measured amount of radioactivity released.</ref>
 !style="background:#ffdead;" class="unsortable" | References
 !style="background:#efefef;" class="unsortable" | Notes
 |- style="vertical-align: top;"
 ! ''[[Upshot-Knothole Annie|Annie]]''{{anchor|Annie}}
 | {{dts|1953|3|17}} 13:20:00.3
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 3
{{coord|37.0477|-116.022|name=Annie|display=inline}}
 | style="text-align: right;" |{{sort|001320|}}{{convert|1230|m|abbr=on}}<br />+ {{convert|90|m|abbr=on}}
 | tower,<br />weapons development
 | [[Mark 5 nuclear bomb|TX-5HE]] "XR-3" Type D pit
 | style="text-align:center;" | {{sort|000160000|16&nbsp;kt}}
 | I-131 detected, {{convert|2.4|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | Investigated yield-vs-initiation time curve. Live news coverage. Desert Rock V. Two 2-story houses, 50 autos, bomb shelters in effects test.
 |- style="vertical-align: top;"
 ! ''Nancy''{{anchor|Nancy}}
 | {{dts|1953|3|24}} 13:10:00.0
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 4
{{coord|37.0955|-116.1037|name=Nancy|display=inline}}
 | style="text-align: right;" |{{sort|001320|}}{{convert|1230|m|abbr=on}}<br />+ {{convert|90|m|abbr=on}}
 | tower,<br />weapons development
 | [[Mark 14 nuclear bomb|TX-14]] "Nevada Zombie"
 | style="text-align:center;" | {{sort|000240000|24&nbsp;kt}}
 | I-131 detected, {{convert|3.6|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | Component test of TX-14<ref name="swordsoarIII" />{{refpage|193, 195}} containing minimal quantities of Li-6D.<ref name="swordsoarIII" />{{refpage|170}} [[Desert Rock V]]. First proof-test of the [[RACER IV|RACER]] boosted primary with disappointing performance.{{refn|group=Note|Apparently the device name is a misnomer, as it implies that the device tested was related to the TX-15 "ZOMBIE". However, this is not the case; no thermonuclear component testing of TX-15 appears to have been conducted during this operation, since Upshot-Knothole tested radiation implosion mockups, ''containing primaries and mocked-up secondaries with small amounts of enriched Li-6'' for the TX-14, TX-16, and TX-17/24 thermonuclear prototype systems, all slated to be proof-fired during [[Operation Castle|CASTLE]].<ref name="swordsoarIII" />{{refpage|193}}}}
 |- style="vertical-align: top;"
 ! ''[[Uranium hydride bomb|Ruth]]''{{anchor|Ruth}}
 | {{dts|1953|3|31}} 13:00:00.0
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 7
{{coord|37.0827|-116.0248|name=Ruth|display=inline}}
 | style="text-align: right;" |{{sort|001360|}}{{convert|1270|m|abbr=on}}<br />+ {{convert|90|m|abbr=on}}
 | tower,<br />weapons development
 | [[Mark 6 nuclear bomb|MK-6]]<ref name="swordsoarVII">{{cite book |author-link=Chuck Hansen |first=Chuck |last=Hansen |title=Swords of Armageddon |volume=VII |date=1995 |url=http://www.uscoldwar.com |access-date=December 28, 2016}}</ref>{{refpage|198}}
"Hydride I"
 | style="text-align:center;" | {{sort|000002000|200&nbsp;t}}
 | I-131 detected, {{convert|28|kCi|TBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_6 /><ref name=LT_1 />
 | 1st UCRL device, a [[uranium deuteride]] core,<ref name="swordsoarIII" />{{refpage|202}} meant to explore deuterated polyethylene mixed with uranium as thermonuclear fuel,<ref name="herk">{{cite book |author-link=Gregg Herken |first=Gregg |last=Herken |title=Brotherhood of the Bomb |url=https://archive.org/details/brotherhoodofbom0000herk |url-access=registration |date=2003}}</ref>{{refpage|chap.15}}<ref name="swordsoarIII" />{{refpage|203}} and if successful to lead also to a compact thermonuclear primary.<ref name="swordsoarIII" />{{refpage|149}} Predicted yield was 1.5 to 3 kilotons, max. theoretical was 20 kt.<ref name="swordsoarVII" />{{refpage|96}} Device [[fizzle (nuclear test)|fizzled]] - deuterium moderated (slowed-down) neutrons more than expected and quenched the reaction. Embarrassing for designers, as it left {{convert|200|ft|abbr=on}} of tower still standing (see [[:File:RUTH test tower 1953-03-31.jpg|image of tower]]).
 |- style="vertical-align: top;"
 ! ''[[Upshot-Knothole Dixie|Dixie]]''{{anchor|Dixie}}
 | {{dts|1953|4|6}} 15:29:38.4
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 7
{{coord|37.0847|-116.0189|name=Dixie|display=inline}}
 | style="text-align: right;" |{{sort|003114|}}{{convert|1284|m|abbr=on}}<br />+ {{convert|1830|m|abbr=on}}
 | free air drop,<br />weapons development
 | [[Mark 5 nuclear bomb|MK-5D]]
"DD-1"<ref name="swordsoarIII" />{{refpage|194}}
 | style="text-align:center;" | {{sort|000110000|11&nbsp;kt}}
 | I-131 detected, {{convert|1.7|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | TX-5D proof test, a boosting experiment using [[lithium hydride|lithium deuteride]] in solid or crystalline form, investigating ''initiation via deuterium''; a cheap method to initiate a chain reaction.<ref name="swordsoarIII" />{{refpage|185}} Exploded {{convert|600|ft|abbr=on}} ENE of intended zero point.
 |- style="vertical-align: top;"
 ! ''[[Uranium hydride bomb|Ray]]''{{anchor|Ray}}
 | {{dts|1953|4|11}} 12:44:59.8
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 4
{{coord|37.09889|-116.09332|name=Ray|display=inline}}
 | style="text-align: right;" |{{sort|001326|}}{{convert|1296|m|abbr=on}}<br />+ {{convert|30|m|abbr=on}}
 | tower,<br />weapons development
 | [[Mark 6 nuclear bomb|MK-6]]<ref name="swordsoarVII" />{{refpage|198}}
"Hydride II"
 | style="text-align:center;" | {{sort|000002000|220&nbsp;t}}<ref name="OpUKSum">{{cite book |title=Operation Upshot-Knothole Summary Report of the Technical Director |date=1953 |url=https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/PB97112866.xhtml |access-date=2019-02-17}}</ref>{{refpage|101}}
 | I-131 detected, {{convert|28|kCi|TBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_6 /><ref name=LT_1 />
 | 2nd UCRL device, uranium deuteride<ref name="swordsoarIII" />{{refpage|202}} meant to explore deuterated polyethylene mixed with uranium as thermonuclear fuel,<ref name="herk" />{{refpage|chap.15}}<ref name="swordsoarIII" />{{refpage|203}} and if successful to lead also to a compact thermonuclear primary;<ref name="swordsoarIII" />{{refpage|149}} Used different mix from ''Ruth''<ref name="swordsoarIII" />{{refpage|202}} and it also fizzled. A 100-foot tower was apparently used to avoid embarrassment in case of fizzle.
 |- style="vertical-align: top;"
 ! ''Badger''{{anchor|Badger}}
 | {{dts|1953|4|18}} 12:35:00.0
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 2
{{coord|37.1383|-116.1187|name=Badger|display=inline}}
 | style="text-align: right;" |{{sort|001460|}}{{convert|1370|m|abbr=on}}<br />+ {{convert|90|m|abbr=on}}
 | tower,<br />weapons development
 | [[Mark 16 nuclear bomb|TX-16]] "Buzzard"
 | style="text-align:center;" | {{sort|000230000|23&nbsp;kt}}
 | I-131 detected, {{convert|3.6|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | Component test of the TX-16 using a cryogenic mockup secondary and the TX-16 radiation case. Also tested RACER primary, which performed below expectations again. Desert Rock V.
 |- style="vertical-align: top;"
 ! ''[[Upshot-Knothole Simon|Simon]]''{{anchor|Simon}}
 | {{dts|1953|4|25}} 12:29:59.8
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 1
{{coord|37.053|-116.1036|name=Simon|display=inline}}
 | style="text-align: right;" |{{sort|001384|}}{{convert|1294|m|abbr=on}}<br />+ {{convert|90|m|abbr=on}}
 | tower,<br />weapons development
 | [[Mark 17 nuclear bomb|TX-17/24]] "Simultaneity"
 | style="text-align:center;" | {{sort|000430000|43&nbsp;kt}}
 | I-131 detected, {{convert|6.3|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | Component test of TX-17/24 series using the RACER IV primary, a modified RACER core containing two additional kilograms of HEU in the original design tested in Nancy, a thermonuclear secondary mockup.<ref name=LT_148 />
 |- style="vertical-align: top;"
 ! ''[[Upshot-Knothole Encore|Encore]]''{{anchor|Encore}}
 | {{dts|1953|5|8}} 15:29:55.4
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 5
{{coord|36.8|-115.929|name=Encore|display=inline}}
 | style="text-align: right;" |{{sort|001680|}}{{convert|940|m|abbr=on}}<br />+ {{convert|740|m|abbr=on}}
 | free air drop,<br />weapon effect
 | [[Mark 6 nuclear bomb|MK-6D]]
 | style="text-align:center;" | {{sort|000270000|27&nbsp;kt}}
 | I-131 detected, {{convert|3.9|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | "Effects" test. Dropped {{convert|950|ft|abbr=on}} SSW of target. Desert Rock V, bad exposures for troops and bad [[downwinder]] fallout.
 |- style="vertical-align: top;"
 ! ''[[Upshot-Knothole Harry|Harry]]''{{anchor|Harry}}
 | {{dts|1953|5|19}} 12:04:59.5
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 3
{{coord|37.0402|-116.0261|name=Harry|display=inline}}
 | style="text-align: right;" |{{sort|001314|}}{{convert|1224|m|abbr=on}}<br />+ {{convert|90|m|abbr=on}}
 | tower,<br />weapons development
 | [[Mark 13 nuclear bomb|TX-13D]] "Hamlet"
 | style="text-align:center;" | {{sort|000320000|32&nbsp;kt}}
 | I-131 detected, {{convert|4.6|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | New hollow core design, most efficient pure-plutonium device under 100&nbsp;kt indicates very good compression. Major effects testing of a high elevation explosion. Heaviest downwind contamination measured.
 |- style="vertical-align: top;"
 ! ''[[Upshot-Knothole Grable|Grable]]''{{anchor|Grable}}
 | {{dts|1953|5|25}} 15:30:00.3
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || Launch from NTS Areas 5, 11, Frenchman Flat: 5
{{coord|36.70428|-115.97387|name=Launch_Grable|display=inline}}, elv: {{convert|950|+|5|m|abbr=on}};<br />Detonation over [[Nevada National Security Site|NTS]] {{coord|36.793|-115.9156|name=Grable|display=inline}}
 | style="text-align: right;" |{{sort|001120|}}{{convert|960|m|abbr=on}}<br />+ {{convert|160|m|abbr=on}}
 | gun deployed,<br />weapon effect
 | [[W9 (nuclear warhead)|W9]] AFAP "Gun"
 | style="text-align:center;" | {{sort|000150000|15&nbsp;kt}}
 | I-131 detected, {{convert|2.1|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | The 2nd of four gun-type device tests. Fired from the M65 Atomic Cannon "''Atomic Annie''" {{convert|11|km|abbr=on}} downrange. 280mm shell, {{convert|365|kg|abbr=on}}. Detonation at {{convert|200|ft}} SW of target. Desert Rock V. Major effects test.
 |- style="vertical-align: top;"
 ! ''Climax''{{anchor|Climax}}
 | {{dts|1953|6|4}} 11:14:56.7
 | style="text-align:center;" | PST (-8&nbsp;hrs)<br /> || [[Nevada National Security Site|NTS]] Area 7
{{coord|37.0875|-116.0192|name=Climax|display=inline}}
 | style="text-align: right;" |{{sort|001698|}}{{convert|1288|m|abbr=on}}<br />+ {{convert|410|m|abbr=on}}
 | free air drop,<br />weapons development
 | [[Mark 7 nuclear bomb|MK-7]], "Cobra", Type D pit
 | style="text-align:center;" | {{sort|000610000|61&nbsp;kt}}
 | I-131 detected, {{convert|8.6|MCi|PBq|abbr=on}}
 | <ref name=LT_150 /><ref name=LT_148 /><ref name=LT_24 /><ref name=LT_6 /><ref name=LT_1 />
 | Proof test of a boosted MK-7 device, intended to be used as a primary in ''Castle''. Initially it was intended only for the TX-15<ref name="swordsoarIII" />{{refpage|195}}. After RACER's inconsistent behaviour it was opted for all "emergency capability" devices instead.<ref name="swordsoarIII" />{{refpage|197}}. The bomb detonated {{convert|320|ft|abbr=on}} NW of target. Composite implosion system in a Type D pit. Used [[Cyclotol]] 75/25 explosive mixture.
 |}
{{reflist|group=note}}

==Gallery==
<gallery class="center" widths="220">
File:Upshot Knothole Grable.gif|Full uncut detonation of Upshot-Knothole ''Grable'', launched out of the ''[[M65 Atomic Cannon|Atomic Annie]]'' device on 5/25/1953. The footage at normal speed is about {{frac|2|1|2}} minutes.
File:Grable Close Up.gif|Close-up slow motion shot of ''Grable'' fire-ball, mach-stem and surface effects,
File:UpshotKnotholeEncore.gif|Upshot-Knothole ''Encore'', 27-kilotons.
File:UpshotKnotholeRuth2.gif|Upshot-Knothole ''Ruth'', 0.2-kilotons.
File:UpshotKnotholeRuth1.gif|Upshot-Knothole ''Ruth'', Note close proximity to highway in foreground as to the scale of detonation.
File:RUTH test tower 1953-03-31.jpg|The mangled tower for the ''Ruth'' test. The explosion failed to level the testing tower, only somewhat damaging it.
File:Operation Upshot-Knothole - Badger 001.jpg|Upshot-Knothole Badger, 23 Kilotons
File:Operation Upshot-Knothole - Harry.jpg|Upshot-Knothole Harry, 32 Kilotons
File:Upshot-Knothole Encore 001.jpg|Encore's Mushroom Cloud from far away
File:Upshot-Knothole Encore (1953) (cloud).jpg|Encore's Mushroom Cloud
File:Upshot-Knothole Nancy 001.jpg|Upshot-Knothole Nancy, 24 Kilotons
File:Upshot-Knothole Dixie 001.jpg|Upshot-Knothole Dixie, 11 Kilotons
File:Operation Upshot-Knothole - Ray - Detonation.ogv|Upshot-Knothole Ray, 220 Tons
File:Upshot-Knothole Simon 002.jpg|Upshot-Knothole Simon, 43 Kilotons
File:Project 30-18 - Operation Upshot-Knothole (Nevada Test Site) Detonation - DPLA - ba2f6b3d7a385526cfccf6d4298bf02e.jpg|Grable's Mushroom Cloud
File:Upshot-Knothole Annie 001.jpg|Upshot-Knothole Annie, 16 Kilotons
File:Upshot-Knothole Badger 001.jpg|Badger's Mushroom Cloud
</gallery>

==References==
;Notes
{{reflist|group=Note}}
;Citations
{{reflist|refs=
<ref name=LT_1>{{citation| last1=Yang| first1=Xiaoping| first2=Robert| last2=North| first3=Carl| last3=Romney| date=August 2000| title=CMR Nuclear Explosion Database (Revision 3)| publisher=SMDC Monitoring Research}}</ref>
<ref name=LT_24>{{citation| last=Hansen| first=Chuck| year=1995| title=The Swords of Armageddon, Vol. 8| publisher=Chukelea Publications| location=Sunnyvale, CA| ISBN=978-0-9791915-1-0}}</ref>
<ref name=LT_150>{{citation| url=http://www.cancer.gov/i131/fallout/Chapter2.pdf| access-date=January 5, 2014| title=Estimated exposures and thyroid doses received by the American people from Iodine-131 in fallout following Nevada atmospheric nuclear bomb tests, Chapter 2| publisher=National Cancer Institute| year=1997}}</ref>
<ref name=LT_148>{{citation| url=http://www.nuclearweaponarchive.org/Usa/Tests| access-date=January 6, 2014| last=Sublette| first=Carey| title=Nuclear Weapons Archive}}</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/20061012160826/http://www.nv.doe.gov/library/publications/historical/DOENV_209_REV15.pdf| archive-date=October 12, 2006}}</ref>
}}
;Bibliography

{{Refbegin|2}}
* {{Cite report |url=https://www.osti.gov/biblio/6380890 |title=Shots ENCORE to CLIMAX, the final four tests of the UPSHOT-KNOTHOLE Series, 8 May - 4 June 1953. Technical report |last=Massie |first=J. |last2=Maag |first2=C. |date=1982-01-15 |publisher=JRB Associates, Inc., McLean, VA (USA) |issue=AD-A-121634/0 |language=English |last3=Rohrer |first3=S. |last4=Shepanek |first4=R.}}
* Chuck Hansen, ''Swords of Armageddon, Version 2'' (Chukelea Publications, 1995–2007)
{{Refend}}

== See also ==
{{Div col|colwidth=15em}}
* [[Nuclear artillery]]
{{div col end}}

== External links ==
{{Commons category|Operation Upshot-Knothole}}
* [http://www.nuclearweaponarchive.org/Usa/Tests/Upshotk.html Operation Upshot-Knothole]
* {{Internet Archive short film|id=gov.doe.0800015|name=Nuclear Test Film - Operation Upshot-Knothole (1953)}}
* {{Internet Archive short film|id=gov.doe.0800016|name=Nuclear Test Film - Operation Upshot-Knothole, 5.2 (1953)}}
* {{Internet Archive short film|id=The280mmGunattheNevadaProvingGround1953|name=The 280 mm Gun at the Nevada Proving Ground (1953)}}
* [http://www.atomicforum.org/usa/operations/upshotknothole/upshotknothole.html Operation Upshot-Knothole - 1953]
* [http://video.google.com/videoplay?docid=7051037931271124293&q=upshot+knothole Film about Upshot Knothole Tests] {{Webarchive|url=https://web.archive.org/web/20110519225012/http://video.google.com/videoplay?docid=7051037931271124293&q=upshot+knothole |date=May 19, 2011 }}
* Rice, James. ''Downwind of the Atomic State: Atmospheric Testing and the Rise of the Risk Society''. (New York University Press, 2023): https://nyupress.org/9781479815340/downwind-of-the-atomic-state/ 
{{US Nuclear Tests}}

{{DEFAULTSORT:Operation Upshot-Knothole}}
[[Category:Explosions in 1953]]
[[Category:Nevada Test Site nuclear explosive tests|Upshot-Knothole]]
[[Category:1953 in military history]]
[[Category:1953 in Nevada]]
[[Category:1953 in the environment]]
[[Category:Articles containing video clips]]