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||Operation Ivy|
|Next test||Operation Castle|
Over 21,000 soldiers took part in the ground exercise Desert Rock V in conjunction with the Grable shot.1 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 individual shots were:
|Name||Date Time (UT2)||Location||Yield||Notes|
|Annie||17 Mar 1953 13:20:00.3||NTS Area 3,||160 !16 kilotons||90 metres (300 ft) tower; weapon development test; TX-5HE; 2 houses, 50 autos, bomb shelter tests; Desert Rock V, Live news coverage|
|Nancy||24 March 1953 13:10:00.0||NTS Area 4,||240 !24 kilotons||90 metres (300 ft) tower; weapons development test; test of RACER boosted primary in TX-15 mock-up; Desert Rock V|
|Ruth||31 March 1953 13:00:00.0||NTS Area 7,||002 !0.2 kilotons||90 metres (300 ft)tower; weapon development test; first UCRL device; uranium hydride device; fizzle, embarrassingly left 200 feet (61 m) of tower in the air.|
|Dixie||6 April 1953 15:29:38.4||NTS Area 7,||110 !11 kilotons||Free drop to 1,830 metres (6,000 ft) altitude; weapon development test; TX-5e; 600 feet (180 m) ENE of target point.|
|Ray||11 April 1953 12:44:59.8||NTS Area 4,||002 !0.2 kilotons||30 metres (98 ft) tower; weapon development test; Second UCRL device, uranium hydride device, fizzle; short tower used reportedly to avoid embarrassment of Ruth.|
|Badger||18 April 1953 12:35:00.0||NTS Area 2,||230 !23 kilotons||90 metres (300 ft) tower; weapon development test; test of RACER primary in TX-16 mock-up; Desert Rock V.|
|Simon||25 April 1953 12:29:59.8||NTS Area 1,||430 !43 kilotons||90 metres (300 ft) tower; weapon development test; test of RACER primary in TX-17/24 mock-up.|
|Encore||8 May 1953 15:29:55.4||NTS Area 5,||270 !27 kilotons||Free drop to 740 metres (2,430 ft) altitude; weapon effects test; Mark 6D; Desert Rock V, bad fallout on troops and downwinders.|
|Harry||19 May 1953 12:04:59.5||NTS Area 3,||320 !32 kilotons||90 metres (300 ft) tower; weapon development test; TX-13 device; high elevation effects tested; largest recorded fallout over downwinders.|
|Grable||25 May 1953 15:30:00.3||NTS Area 5,||150 !15 kilotons||nuclear artillery; weapon effects test; W9 gun-type fission weapon 280 millimetres (11 in) shell (one of only four gun-types ever tested) fired 11 kilometres (6.8 mi) downrange; Desert Rock V; low elevation effects tested; possibly most photogenic land explosion.|
|Climax||4 June 1953 11:14:56.7||NTS Area 7,||610 !61 kilotons||Free drop to 400 metres (1,300 ft); weapon development test; Mark 7; first use of safer explosives.|
- 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
- Local time (PST) is 8 hours less than UT (7 for PDT); local date is the day before UT if UT time is before 08:00 (07:00 PDT).
|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