Operation Upshot–Knothole was a series of eleven nuclear test shots conducted in 1953 at the

Nevada Test Site The Nevada National Security Sites (N2S2 or NNSS), popularized as the Nevada Test Site (NTS) until 2010, is a reservation of the United States Department of Energy located in the southeastern portion of Nye County, Nevada, about northwest of ...

. It followed ''

Operation Ivy Operation Ivy was the eighth series of American nuclear tests, coming after '' Tumbler-Snapper'' and before '' Upshot–Knothole''. The two explosions were staged in late 1952 at Enewetak Atoll in the Pacific Proving Ground in the Marshall I ...

'' and preceded ''

Operation Castle Operation Castle was a United States series of high-yield (high-energy) nuclear tests by Joint Task Force 7 (JTF-7) at Bikini Atoll beginning in March 1954. It followed ''Operation Upshot–Knothole'' and preceded '' Operation Teapot''. Con ...

''. Over 21,000 soldiers took part in the ground exercise Desert Rock V in conjunction with the '' Upshot-Knothole Grable'' shot. ''Grable'' was a 280mm Artillery Fired Atomic Projectile (AFAP) shell fired from the " 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

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) by University of California Radiation Laboratory—Livermore (now

Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a Federally funded research and development centers, federally funded research and development center in Livermore, California, United States. Originally established in 1952, the laboratory now i ...

), and for testing out some of the thermonuclear components that would be used for the massive thermonuclear series of

. One primary device ( RACER) was tested in thermonuclear system mockup assemblies of

TX-14 Texas's 14th congressional district for the United States House of Representatives stretches from Freeport to Orange, Texas. It formerly covered the area south and southwest of the Greater Houston region, including Galveston, in the state of T ...

, TX-16, and TX-17/ 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

Castle A castle is a type of fortification, fortified structure built during the Middle Ages predominantly by the nobility or royalty and by Military order (monastic society), military orders. Scholars usually consider a ''castle'' to be the private ...

. Following RACER's dodgy performance, the COBRA primary was used in the emergency capability

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, JUGHEAD, RUNT I, RUNT II thermonuclear devices, as well as in the

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device. RACER IV (as redesigned and proof-tested in the

Simon Simon may refer to: People * Simon (given name), including a list of people and fictional characters with the given name Simon * Simon (surname), including a list of people with the surname Simon * Eugène Simon, French naturalist and the genus ...

test) was employed as primary for the ZOMBIE, RAMROD and MORGENSTERN devices. Navy scientist Pauline Silvia conducted experiments during the tests, and would later be profiled in the 2010 documentary Atomic Mom.

Nuclear tests

Annie

Planned yield for Annie was , actual yield based on radiochemical analysis was .

Nancy

Planned yield for Nancy was , actual yield based on radiochemical analysis was .

Simon

Planned yield for Simon was , actual yield based on radiochemical analysis was .

Harry

Planned yield for Harry was , actual yield based on radiochemical analysis was .

Encore

Planned yield for Encore was , actual yield based on radiochemical analysis was .

List of tests

Gallery

File:Upshot Knothole Grable.gif, Full uncut detonation of Upshot-Knothole ''Grable'', launched out of the '' Atomic Annie'' device on 5/25/1953. The footage at normal speed is about 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

References

;Notes ;Citations ;Bibliography * * Chuck Hansen, ''Swords of Armageddon, Version 2'' (Chukelea Publications, 1995–2007)

External links

Operation Upshot-Knothole
* * *

Film about Upshot Knothole Tests
* 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/ {{DEFAULTSORT:Operation Upshot-Knothole Explosions in 1953 Upshot-Knothole 1953 in military history 1953 in Nevada 1953 in the environment Articles containing video clips