Operation Plumbbob Explained

Operation Plumbbob
Picture Description:Plumbbob-Priscilla, 37-kilotons.
Country:United States
Test Site:
  • NTS Area 12, Rainier Mesa
  • NTS Areas 5, 11, Frenchman Flat
  • NTS, Areas 1–4, 6–10, Yucca Flat
Period:1957
Number Of Tests:29
Test Type:balloon, dry surface, high alt rocket (30 - 80 km), tower, underground shaft, tunnel
Max Yield:74ktTNT
Next Series:Project 58/58A

Operation Plumbbob was a series of nuclear tests that were conducted between May 28 and October 7, 1957, at the Nevada Test Site, following Project 57, and preceding Project 58/58A.

Background

The operation consisted of 29 explosions, of which only two did not produce any nuclear yield. Twenty-one laboratories and government agencies were involved. While most Operation Plumbbob tests contributed to the development of warheads for intercontinental and intermediate range missiles, they also tested air defense and anti-submarine warheads with smaller yields. They included 43 military effects tests on civil and military structures, radiation and bio-medical studies, and aircraft structural tests. Operation Plumbbob had the tallest tower tests to date in the U.S. nuclear testing program as well as high-altitude balloon tests. One nuclear test involved the largest troop maneuver ever associated with U.S. nuclear testing.

Approximately 18,000 members of the U.S. Air Force, Army, Navy and Marines participated in exercises Desert Rock VII and VIII during Operation Plumbbob. The military was interested in knowing how the average foot-soldier would stand up, physically and psychologically, to the rigors of the tactical nuclear battlefield.

Almost 1,200 pigs were subjected to bio-medical experiments and blast-effects studies during Operation Plumbbob. On shot Priscilla (37 kt), 719 pigs were used in various experiments on Frenchman Flat. Some pigs were placed in elevated cages and provided with suits made of different materials, to test which materials provided best protection from the thermal radiation. As shown and reported in the PBS documentary Dark Circle, the pigs survived, but with third-degree burns to 80% of their bodies.[1] Other pigs were placed in pens behind large sheets of glass at measured distances from the hypocenter to test the effects of flying debris on living targets.

Studies were conducted of radioactive contamination and fallout from a simulated accidental detonation of a weapon; and projects concerning earth motion, blast loading and neutron output were carried out.

Nuclear weapons safety experiments were conducted to study the possibility of a nuclear weapon detonation during an accident. On July 26, 1957, a safety experiment, Pascal-A, was detonated in an unstemmed hole at the Nevada Test Site, becoming the first underground shaft nuclear test. The knowledge gained provided data to prevent nuclear yields in case of accidental detonations—for example, in a plane crash.

The John shot on July 19, 1957, was the only test of the Air Force's AIR-2A Genie rocket with a nuclear warhead.[2] It was fired from an F-89J Scorpion fighter over Yucca Flats at the Nevada National Security Site. On the ground, the Air Force carried out a public relations event by having five Air Force officers and a motion picture photographer stand under ground zero of the blast, which took place at between 18500feetand20000feetft (andft) altitude, with the idea of demonstrating the possibility of the use of the weapon over civilian populations without ill effects.[3] The five officers were Colonel Sidney C. Bruce, later professor of Electrical Engineering at Colorado University, died in 2005; Lieutenant Colonel Frank P. Ball, died in 2003; Major John w. Hughes II, died in 1990; Major Norman B. Bodinger, died in 1997; Major Donald A. Luttrell, died in 2014.[4] The videographer, Akira "George" Yoshitake, died in 2013.[5]

The Rainier shot, conducted September 19, 1957, was the first fully contained underground nuclear test, meaning that no fission products were vented into the atmosphere. This test of 1.7 kt could be detected around the world by seismologists using ordinary seismic instruments. The Rainier test became the prototype for larger and more powerful underground tests.

Images from Upshot-Knothole Grable were accidentally relabeled as belonging to the Priscilla shot from Operation Plumbbob in 1957. As a consequence publications including official government documents have the photo mislabeled. The shots can be told apart by the trails of test rockets, which are prominently featured in images and footage of Grable, but appear almost completely absent at the actual Priscilla shot.[6]

Missing steel bore cap

In 1956, Robert Brownlee, from Los Alamos National Laboratory in New Mexico, was asked to examine whether nuclear detonations could be conducted underground. The first subterranean test was the nuclear device known as Pascal A, which was lowered down a 500feet borehole. However, the detonated yield turned out to be 50,000 times greater than anticipated, creating a jet of fire that shot hundreds of feet into the sky. During the Pascal-B nuclear test of August 1957,[7] a 900kg (2,000lb) iron lid was welded over the borehole to contain the nuclear blast, despite Brownlee predicting that it would not work. When Pascal-B was detonated, the blast went straight up the test shaft, launching the cap into the atmosphere at a speed of more than 66km/s. The plate was never found. Scientists believe compression heating caused the cap to vaporize as it sped through the atmosphere.[8] A high-speed camera, which took one frame per millisecond, was focused on the borehole because studying the velocity of the plate was deemed scientifically interesting.[8] After the detonation, the plate appeared in only one frame, but this was enough to make an estimation of its speed. Brownlee joked the best estimate of the cover's speed from the photographic evidence was it was "going like a bat!". Brownlee estimated that the explosion, combined with the specific design of the shaft, could accelerate the plate to approximately six times Earth's escape velocity.[9]

List of tests

See also: List of nuclear weapons tests of the United States.

United States' Plumbbob series tests and detonations
-NameDate time (UT)
(local: PST, −8 hrs)[10]
Location[11] Elevation + height [12] Delivery [13]
Purpose [14]
Device[15] Yield[16] Fallout[17] References Notes - ! Boltzmann 11:55:00.2 NTS Area 7c 37.0947°N -116.0245°W 1294m (4,245feet) + 150m (490feet) tower,
weapons development
I-131 venting detected, 1.9MCi XW-40 lightweight boosted fission warhead test. - ! Franklin 11:54:59.9 NTS Area T3 37.0477°N -116.022°W 1229m (4,032feet) + 90m (300feet) tower,
weapons development
XW-30 ? I-131 venting detected, 19kCi XW-30 warhead test, fizzled. Retested successfully with Franklin Prime, with more fissile material in the core and different explosives. - ! Lassen 11:45:00.3 NTS Area B9a ~ 37.1347°N -116.0417°W 1595m (5,233feet) + 150m (490feet) balloon,
weapons development
I-131 venting detected, 100Ci Fizzle, unboosted all-oralloy small weapon design. - ! Wilson 11:45:00.3 NTS Area B9a ~ 37.1347°N -116.0417°W 1589m (5,213feet) + 150m (490feet) balloon,
weapons development
I-131 venting detected, 1.5MCi XW-45X1 Swan test, gas-boosted composite pit. - ! Priscilla 13:30:00.1 NTS Area 5 36.798°N -115.9298°W 940m (3,080feet) + 210m (690feet) balloon,
weapons development
Mk-15/39 primary I-131 venting detected, 5.8MCi Effects shot with OTS weapon. Similar to that tested in Redwing Lacrosse. - ! Coulomb-A 17:30:?? NTS Area S3h 37.053°N -116.034°W 1231m (4,039feet) + 0 dry surface,
safety experiment
Safety experiment, successful. - ! Hood 11:40:00.1 NTS Area B9a ~ 37.1347°N -116.0417°W 1285m (4,216feet) + 460m (1,510feet) balloon,
weapons development
Swan primary and Whistle secondary. Full-scale test of device was Hardtack I Maple shot.[18] I-131 venting detected, 11MCi Largest atmospheric test in CONUS. Was a 2-stage thermonuclear device, even though AEC stated that no thermonuclear devices were being tested at the NTS. Desert Rock VII. - ! Diablo 11:30:00.1 NTS Area T2b 37.1502°N -116.1095°W 1367m (4,485feet) + 150m (490feet) tower,
weapons development
Swan I-131 venting detected, 2.5MCi Very similar to the Shasta test device. 2 stage. Misfired at first firing attempt three days earlier. - ! John 14:00:04.6 Launch from NTS, Areas 1–4, 6–10, Yucca Flat: 10 37°N -116.0539°W, elv: 1220m+5600mm (4,000feet+18,400feetm);
Detonation over NTS 37.1605°N -116.0539°W
1280m (4,200feet) + 5639m (18,501feet) Air launched rocket, weapon effect I-131 venting detected, 6.1MCi? Proof test of AIR-2A Genie air-to-air rocket. Test made famous by five USAF officers and a videographer standing at ground zero below the hypocentre and during the detonation, flash and blast. - ! Kepler 11:49:59.9 NTS Area 4 37.0955°N -116.1035°W 1318m (4,324feet) + 150m (490feet) tower,
weapons development
XW-35 primary? I-131 venting detected, 1.7MCi ICBM warhead, similar to Hardtack I/Koa. - ! Owens 13:29:59.7 NTS Area B9b ~ 37.1347°N -116.0417°W 1260m (4,130feet) + 150m (490feet) balloon,
weapons development
XW-51 ? I-131 venting detected, 1.7MCi Very small boosted plutonium device, XW-51 progenitor. - ! 08:00:00.0 NTS Area U3j 37.0518°N -116.0342°W 1202m (3,944feet)–150m (490feet) underground shaft,
safety experiment
I-131 venting detected, 10kCi Originally Galileo A. One-point safety experiment, failure. Expected yield was less than 1 kg. A concrete cylinder perhaps 2m (07feet) thick 100m (300feet) up the tube disappeared. - ! Stokes 12:25:00.2 NTS Area B7b ~ 37.0866°N -116.0245°W 1250m (4,100feet) + 460m (1,510feet) balloon,
weapons development
I-131 venting detected, 2.8MCi Tactical Atomic Demolition Munition (TADM) and Talos SAM warhead. - ! Saturn 00:59:55.1 NTS Area U12c.02 37.1936°N -116.2006°W 1231m (4,039feet)–39.01m (127.99feet) tunnel,
safety experiment
One-point safety experiment
first shot in a Rainier tunnel.
- ! Shasta 12:00:00.0 NTS Area 2a 37.128°N -116.1073°W 1339m (4,393feet) + 150m (490feet) tower,
weapons development
Swan I-131 venting detected, 2.5MCi 2 stage thermonuclear design. - ! Doppler 12:30:00.1 NTS Area B7b ~ 37.0866°N -116.0245°W 1282m (4,206feet) + 460m (1,510feet) balloon,
weapons development
XW-34 ? I-131 venting detected, 1.7MCi LASL gas boosted implosion device, possible XW-34 test. - ! Pascal-B 22:35:00.0 NTS Area U3d 37.049°N -116.0347°W 1229m (4,032feet)–150m (490feet) underground shaft,
safety experiment
Shaft safety experiment, failed. Sent the shaft cap weighing several hundred pounds (1 ton) at velocity very roughly pre-calculated as 66km/s; popular claims of it reaching space are disputed, see section above.
Franklin Prime 12:39:59.9 NTS Area B7b ~ 37.0866°N -116.0245°W 1282m (4,206feet) + 230m (760feet) balloon,
weapons development
I-131 venting detected, 690kCi Retest of Franklin with more U-235. - ! Smoky 12:30:00.0 NTS Area T2c 37.1871°N -116.0689°W 1367m (4,485feet) + 210m (690feet) tower,
weapons development
TX-41 primary I-131 venting detected, 6.4MCi 2 stages of 3 stage thermonuke, similar to Redwing/Zuni and Tewa. Desert Rock VII; 3000 servicemen irradiated; 10 of 4 expected leukemia cases in the 80s. Last pristine air-drop location at the NTS. - ! Galileo 12:40:00.0 NTS Area T1 37.053°N -116.1034°W 1294m (4,245feet) + 150m (490feet) tower,
weapons development
I-131 venting detected, 1.9MCi LASL diagnostic/exploratory test of boosted fission device. Desert Rock VIII. - ! Wheeler 12:45:00.0 NTS Area B9a ~ 37.1347°N -116.0417°W 1286m (4,219feet) + 150m (490feet) balloon,
weapons development
XW-51 ? I-131 venting detected, 27kCi Retest of redesigned Lassen device, possible XW-51 air-to-air warhead progenitor. - ! Coulomb-B 20:05:00.6 NTS Area S3g 37.0427°N -116.0277°W 1225m (4,019feet) + 0 dry surface,
safety experiment
I-131 venting detected, 42kCi One-point safety experiment, high limits test, expected 1 kg TNT equivalent, max .2 kt - failure. - ! Laplace 12:59:59.8 NTS Area B7b ~ 37.0866°N -116.0245°W 1282m (4,206feet) + 230m (760feet) balloon,
weapons development
XW-33 "Fleegle" I-131 venting detected, 140kCi Oralloy gun-type device, for a nuclear artillery shell. The third of only four gun-type weapons, with Little Boy, Grable and Aardvark. - ! Fizeau 16:44:59.8 NTS Area T3b 37.0336°N -116.0323°W 1220m (4,000feet) + 150m (490feet) tower,
weapons development
XW-34 ? I-131 venting detected, 1.7MCi LASL boosted fission device. Possibly a test of the XW-34 depth bomb. - ! Newton 12:49:59.9 NTS Area B7a ~ 37.0866°N -116.0245°W 1282m (4,206feet) + 460m (1,510feet) balloon,
weapons development
I-131 venting detected, 2.1MCi LASL test of XW-31 variant, boosted primary in thermonuclear system mockup. Sounds like a fizzle, but no one says so. - ! Rainier 16:59:59.45 NTS Area U12b 37.1957°N -116.204°W 2295m (7,530feet)–272.8m (895feet) tunnel,
weapons development
First US underground nuclear test. Evaluate containment and detection of underground testing, formed a chimney of broken rock which provided data on possible underground engineering applications of nuclear explosives. - ! Whitney 12:29:59.8 NTS Area T2 37.1383°N -116.1184°W 1370m (4,500feet) + 150m (490feet) tower,
weapons development
W27 primary I-131 venting detected, 2.9MCi Test of boosted Swan primary in W-27 thermonuclear system mockup. - ! Charleston 12:59:59.9 NTS Area B9a ~ 37.1347°N -116.0417°W 1285m (4,216feet) + 460m (1,510feet) balloon,
weapons development
I-131 venting detected, 1.8MCi UCRL test of a small "clean" tactical 2-stage thermonuclear device. Device fizzled when second stage failed to fire. - ! Morgan 13:00:00.1 NTS Area B9a ~ 37.1347°N -116.0417°W 1285m (4,216feet) + 150m (490feet) balloon,
weapons development
XW-45X1 Swan/Flamingo I-131 venting detected, 1.2MCi

See also

External links

Notes and References

  1. Dark Circle . March 27, 2007 . Judy Irving, Chris Beaver, Ruth Landy (directors) . DVD . 0-7670-9304-6 . September 7, 2017 . August 11, 2019 . https://web.archive.org/web/20190811113037/http://www.pbs.org/pov/darkcircle/ . live .
  2. News: Five Men Agree To Stand Directly Under An Exploding Nuclear Bomb. Robert Krulwich. NPR. July 17, 2012. April 3, 2018. April 26, 2015. https://web.archive.org/web/20150426133157/http://www.npr.org/blogs/krulwich/2012/07/16/156851175/five-men-agree-to-stand-directly-under-an-exploding-nuclear-bomb. live.
  3. News: George Yoshitake, Nuclear Test Photographer, Recalls Filming Nuclear Blast 55 Years Ago. Timothy Stenovec. Huffington Post. July 20, 2012. July 22, 2013. December 14, 2012. https://web.archive.org/web/20121214073601/http://www.huffingtonpost.com/2012/07/20/george-yoshitake-nuclear-test-five-5-men-nevada_n_1687233.html. live.
  4. News: Donald Allen Luttrell (obituary). Dallas Morning News. January 1, 2015. February 15, 2015. March 3, 2016. https://web.archive.org/web/20160303204709/http://www.legacy.com/obituaries/dallasmorningnews/obituary.aspx?pid=173687969. live.
  5. News: Akira "George" Yoshitake (obituary). Lompoc Record. Lompoc, California, US. October 22, 2013. May 17, 2014. June 14, 2017. https://web.archive.org/web/20170614005708/http://lompocrecord.com/lifestyles/announcements/obituaries/akira-george-yoshitake/article_e7d7490d-8347-5fab-a8ed-6e0adf725271.html. live.
  6. Web site: Sublette . Carey . Operation Plumbbob . live . https://web.archive.org/web/20031213232218/http://nuclearweaponarchive.org/Usa/Tests/Plumbob.html . December 13, 2003 . December 27, 2006 . Nuclear Weapon Archive.
  7. Web site: The fastest object ever launched was a manhole cover – here's the story from the guy who shot it into space . Harrington, Rebecca . February 5, 2016 . . 11 June 2021 . November 1, 2020 . https://web.archive.org/web/20201101025542/https://www.businessinsider.com/fastest-object-robert-brownlee-2016-2?r=US&IR=T#brownlee-wanted-to-measure-how-fast-the-iron-cap-flew-off-the-column-so-he-designed-a-second-experiment-pascal-b-9 . live.
  8. Web site: Science: Did speeding American manhole cover beat Sputnik into space? Top boffin speaks to El Reg - How a nuke blast lid may have beaten Soviets by months . Thomson, Iain . 16 July 2015 . . 11 June 2021 . May 7, 2021 . https://web.archive.org/web/20210507102307/https://www.theregister.com/2015/07/16/america_soviets_space_race/ . live .
  9. Web site: Learning to Contain Underground Nuclear Explosions. Robert R.. Brownlee. June 2002. July 31, 2006.
  10. To convert the UT into standard local PST, subtract 8 hours. If the result is earlier than 00:00, add 24 hours and subtract 1 from the day. Historical time zone data are derived from Web site: Time Zone Historical Database. iana.com. March 8, 2014. March 11, 2014. https://web.archive.org/web/20140311224729/http://www.ietf.org/timezones/. live.
  11. 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.
  12. Elevation is the ground level at the point directly below the explosion relative to sea level; height is the additional distance added or 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.
  13. Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, and barge have all been disallowed by the Partial Nuclear Test Ban Treaty since 1963. 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.
  14. Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
  15. 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.
  16. Estimated energy yield in tons or kilotons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie).
  17. 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.
  18. Book: Chuck Hansen. 978-0-9791915-6-5. VI. Swords of Armageddon. 2007. 392.