The Grable test, including the artillery piece used to fire the warhead.
|Test site||Nevada Test Site|
|Number of tests||11|
|Test type||Atmospheric tests|
|Max. yield||61 kilotons of TNT (260 TJ)|
|Previous test series||Operation Ivy|
|Next test series||Operation Castle|
Over 21,000 soldiers took part in the ground exercise Desert Rock V in conjunction with the Grable shot. Grable was a 280mm 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 atomic artillery shell was fired (shot Grable), the first two shots (both 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.
The detonations[Table 1] in Operation Upshot-Knothole are listed below:
|Name[Table 2]||Date Time (UT[Table 3])||Location[Table 4]||Elevation + Height[Table 5]||Delivery[Table 6]||Purpose[Table 7]||Device[Table 8]||Yield[Table 9]||Venting[Table 10]||Notes|
|Annie||March 17, 1953 13:00:20.3||NTS Area 3||1,230 m (4,040 ft) + 90 m (300 ft)||Tower||Weapons development||TX-5HE "XR3" Type D pit||16 kt||Vent (I131), 2.4 MCi (89 PBq)||Investigated yield-vs-initiation time curve. Live news coverage. Desert Rock V. Two 2-story houses, 50 autos, bomb shelters in effects test.|
|Nancy||March 24, 1953 13:00:10.0||NTS Area 4||1,230 m (4,040 ft) + 90 m (300 ft)||Tower||Weapons development||TX-15 "Nevada Zombie"||24 kt||Vent (I131), 3.6 MCi (130 PBq)||Proof test of TX-15. Desert Rock V. Tested RACER boosted primary.|
|Ruth||March 31, 1953 13:00:00.0||NTS Area 7||1,270 m (4,170 ft) + 90 m (300 ft)||Tower||Weapons development||"Hydride 1"||200 t||Vent (I131), 28 kCi (1,000 TBq)||1st UCRL device, a uranium hydride core pushed by Teller, meant to be a thermonuclear primary. Device fizzled - hydride to slow neutrons was too slow; the weapon blew apart while waiting. Embarrassing for designers, as it left 200 ft (61 m) of shot tower still standing.|
|Dixie||April 6, 1953 15:29:38.4||NTS Area 7||1,284 m (4,213 ft) + 1,830 m (6,000 ft)||Air drop, free fall||Weapons development||Mk-5D||11 kt||Vent (I131), 1.7 MCi (63 PBq)||Lithium hydride boost experiment. Exploded 600 ft (180 m) ENE of intended zero point.|
|Ray||April 11, 1953 12:44:59.8||NTS Area 4||1,296 m (4,252 ft) + 30 m (98 ft)||Tower||Weapons development||"Hydride 2"||200 t||Vent (I131), 28 kCi (1,000 TBq)||2nd UCRL device, uranium deuteride device; it also fizzled. Legend has it that the 100 foot (30 m) tower was used to avoid embarrassment in case of fizzle.|
|Badger||April 18, 1953 12:00:35.0||NTS Area 2||1,370 m (4,490 ft) + 90 m (300 ft)||Tower||Weapons development||TX-16 "Buzzard"||23 kt||Vent (I131), 3.6 MCi (130 PBq)||Test of the TX-16 cryogenic design. Test of the RACER primary in TX-16 mock-up. Desert Rock V.|
|Simon||April 25, 1953 12:29:59.8||NTS Area 1||1,294 m (4,245 ft) + 90 m (300 ft)||Tower||Weapons development||TX-17/24 "Simultaneity"||43 kt||Vent (I131), 6.3 MCi (230 PBq)||Test of RACER primary in TX-16 mock-up; Desert Rock V.|
|Encore||May 8, 1953 15:29:55.4||NTS Area 5||940 m (3,080 ft) + 740 m (2,430 ft)||Air drop, free fall||Weapon effect||Mk-6D||27 kt||Vent (I131), 3.9 MCi (140 PBq)||"Effects" test. Dropped 950 ft (290 m) SSW of target. Desert Rock V, bad exposures for troops and bad downwinder fallout.|
|Harry||May 19, 1953 12:04:59.5||NTS Area 3||1,224 m (4,016 ft) + 90 m (300 ft)||Tower||Weapons development||TX-13D "Hamlet"||32 kt||Vent (I131), 4.6 MCi (170 PBq)||New hollow core design, most efficient pure plutonium device under 100kT indicates very good compression. Major effects testing of a high elevation explosion. Heaviest downwind contamination measured.|
|Grable||May 25, 1953 15:00:30.3||NTS Area 5||960 m (3,150 ft) + 160 m (520 ft)||Gun deployed||Weapon effect||W9 AFAP||15 kt||Vent (I131), 2.1 MCi (78 PBq)||The second of four gun-type device tests, with Little Boy, Laplace and Aardvark. Fired from "Atomic Annie" M65 Atomic Cannon 11 km (6.8 mi) downrange. 280mm shell, 1.4 m long, 365 kg. Detonated 200 ft (61 m) SW of target. Desert Rock V. Major effects test for low blast.|
|Climax||June 4, 1953 11:14:56.7||NTS Area 7||1,288 m (4,226 ft) + 410 m (1,350 ft)||Air drop, free fall||Weapons development||Mk-7, COBRA core, Type D pit||61 kt||Vent (I131), 8.6 MCi (320 PBq)||Proof test of Mk 7, detonated 320 ft (98 m) NW of target. Composite COBRA implosion system in a Type D pit, later used as a primary. Used safer Cyclotol 75/25 explosive mixture.|
- A bomb test may be a salvo test, defined as two or more explosions "where a period of time between successive individual explosions does not exceed 5 seconds and where the burial points of all explosive devices can be connected by segments of straight lines, each of them connecting two burial points and does not exceed 40 kilometers in length". Mikhailov, V. N., Editor in Chief. Catalog of World Wide Nuclear Testing. Begell-Atom, LLC.
- An appended number represents a member of a salvo test. They usually all have the same name, like Tub-A, Tub-B, ..., but early on had separate names, so other members are denoted by "(with xyz)".
- Universal Time at the Nevada National Security Site is 8 hours after local time; UT dates are one day after local date for UT times after 16:00.
- Rough place name and a Latitude/Longitude reference. Some 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.
- 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 or other contrivance. For air bursts it is the absolute altitude of the explosion disregarding ground level (though the ground level is given for comparison), and for rockets the ground level is "N/A".
- Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, barge and cratering are all disallowed by the Partial Nuclear Test Ban Treaty. Sealed shaft and tunnel are underground, and remained useful under the PTBT.
- Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
- Designations for test items where known, nicknames for individual bombs in quotes.Names are "Mark #" or "B#" for bombs, "W#" for rocket warheads, "X#" for experimental, plus code names like "Piccolo". "Primary" refers to a test of only the primary (fission) stage of a multi-stage bomb.
- Estimated energy yield in tonnes, kilotonnes, and megatonnes (and yes, they are all metric units).
- Emissions to atmosphere, where known. 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, and the maximum amount released, in Curies ("Ci") with metric prefixes.
- Griggs, D. T., and Frank Press (1961). "Probing the earth with nuclear explosions". Journal of Geophysical Research. 66(1): 237–258.
- United States Nuclear Tests: July 1945 through September 1992 (Revision 15). Department of Energy, Nevada Operations Office. December 2000. Retrieved 2013-10-26.
- Yang, Xiaoping, Robert North, and Carl Romney (August 2000). CMR Nuclear Explosion Database (Revision 3). SMDC Monitoring Research. Retrieved 2013-10-26.
- Hansen, Chuck (1995). The Swords of Armageddon, Vol. 8. Chukelea Publications (Sunnyvale, CA). ISBN 978-0-9791915-1-0.
- Operation UPSHOT-KNOTHOLE Fact Sheet, Defense Threat Reduction Agency
|Wikimedia Commons has media related to Operation Upshot-Knothole.|
- Operation Upshot-Knothole
- The short film Nuclear Test Film - Operation Upshot-Knothole (1953) is available for free download at the Internet Archive [more]
- The short film Nuclear Test Film - Operation Upshot-Knothole, 5.2 (1953) is available for free download at the Internet Archive [more]
- The short film The 280 mm Gun at the Nevada Proving Ground (1953) is available for free download at the Internet Archive [more]
- Operation Upshot-Knothole - 1953
- Film about Upshot Knothole Tests