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Operation Upshot-Knothole
The Grable test, including the artillery piece used to fire the warhead.
Information
Country United States
Test site Nevada Test Site
Period March–June 1953
Number of tests 11
Test type Atmospheric tests
Device type Fission
Max. yield 61 kilotons of TNT (260 TJ)
Navigation
Previous test Operation Ivy
Next test Operation Castle

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 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:

Upshot-Knothole tests
Name Date Time (UT[2]) Location Yield Notes
Annie Mar 17, 1953 13:20:00.3 NTS Area 3, 37°02′52″N 116°01′19″W / 37.0477°N 116.022°W / 37.0477; -116.022 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 March 24, 1953 13:10:00.0 NTS Area 4, 37°05′44″N 116°06′13″W / 37.0955°N 116.1037°W / 37.0955; -116.1037 24 kilotons 90 metres (300 ft) tower; weapons development test; test of RACER boosted primary in TX-15 mock-up; Desert Rock V
Ruth March 31, 1953 13:00:00.0 NTS Area 7, 37°04′58″N 116°01′29″W / 37.0827°N 116.0248°W / 37.0827; -116.0248 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 April 6, 1953 15:29:38.4 NTS Area 7, 37°05′05″N 116°01′08″W / 37.0847°N 116.0189°W / 37.0847; -116.0189 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 April 11, 1953 12:44:59.8 NTS Area 4, 37°05′56″N 116°05′36″W / 37.0988°N 116.0934°W / 37.0988; -116.0934 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 April 18, 1953 12:35:00.0 NTS Area 2, 37°08′18″N 116°07′07″W / 37.1383°N 116.1187°W / 37.1383; -116.1187 23 kilotons 90 metres (300 ft) tower; weapon development test; test of RACER primary in TX-16 mock-up; Desert Rock V.
Simon April 25, 1953 12:29:59.8 NTS Area 1, 37°03′11″N 116°06′13″W / 37.053°N 116.1036°W / 37.053; -116.1036 43 kilotons 90 metres (300 ft) tower; weapon development test; test of RACER primary in TX-17/24 mock-up.
Encore May 8, 1953 15:29:55.4 NTS Area 5, 36°48′00″N 115°55′44″W / 36.8°N 115.929°W / 36.8; -115.929 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 May 19, 1953 12:04:59.5 NTS Area 3, 37°02′25″N 116°01′34″W / 37.0402°N 116.0261°W / 37.0402; -116.0261 32 kilotons 90 metres (300 ft) tower; weapon development test; TX-13 device; high elevation effects tested; largest recorded fallout over downwinders.
Grable May 25, 1953 15:30:00.3 NTS Area 5, 36°47′35″N 115°54′56″W / 36.793°N 115.9156°W / 36.793; -115.9156 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 June 4, 1953 11:14:56.7 NTS Area 7, 37°05′15″N 116°01′09″W / 37.0875°N 116.0192°W / 37.0875; -116.0192 61 kilotons Free drop to 400 metres (1,300 ft); weapon development test; Mark 7; first use of safer explosives.

References

  1. Operation UPSHOT-KNOTHOLE Fact Sheet, Defense Threat Reduction Agency
  2. 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).

External links

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