Operation Plumbbob

Operation Plumbbob was conducted at the Nevada Test Site (NTS) from May through October of 1957. It was the sixth test series at NTS and consisted of 29 tests. Six of these were safety tests, and two did not produce any nuclear yield. This series addressed several objectives, including tactical weapon proof tests, safety tests, and component and mockup testing for thermonuclear systems to be detonated in Hardtack I, among other things.

During Plumbbob 16,000 DOD personnel participated in the Desert Rock VII and VIII exercises. 

Shot Boltzmann. Yield of 12 kilotons using a XW-40 fusion-boosted fission warhead via a 500 Foot Shot Tower. NTS, Nevada. 28 May 1957 

Shot Priscilla. Yield of 37 kilotons using a Mk-15 thermonuclear bomb using a balloon hoisted to 700 feet. NTS, Nevada. 24 June 1957

Shot Hood. Yield of 75 kilotons using a “Swan” thermonuclear device via a balloon hoisted to 1500 feet. Hood was the largest atmospheric test ever conducted at NTS and in the continental U.S. This was a test of a two-stage thermonuclear device designed by UCRL (University of California Radiation Laboratory), even though the U.S. government stated at the time that no thermonuclear tests were being conducted in Nevada. Operation Desert Rock VII took place at the same time. NTS, Nevada. 5 July 1957

Shot Diablo. Yield of 17 kilotons using a “Swan” thermonuclear device via a 500 Foot Tower Shot. This was a UCRL developmental test of a two stage thermonuclear design. NTS, Nevada. 15 July 1957

Shot John. Yield of 1.7 kilotons using a AIR-2A Genie air-to-air rocket fired from a F-89J at 18,500 feet. The test was made famous by five USAF officers and a videographer standing at ground zero below the hypocentre and during the detonation, flash and blast. NTS, Nevada. 19 July 1957

Shot Keplar. Yield of 10 kilotons using a XW-35 thermonuclear warhead via a 500 Foot Tower Shot. The XW-35 was designed from the outset as a thermonuclear warhead for the first generation of ICBMs. NTS, Nevada. 25 July 1957

Shot Stokes. Yield of 19 kilotons using a XW-30 thermonuclear warhead using a balloon hoisted to 1500 feet. Test of the XW-30 multi-purpose warhead; used in TADM (tactical atomic demolition munition), and Talos SAM (surface-air-missile) warhead. NTS, Nevada. 7 August 1957

Shot Smoky. Yield of 44 kilotons using a TX-41 thermonuclear bomb via a 700 Foot Tower Shot. The TX-41 would become the B-41 nuclear bomb, the most powerful bomb developed by the US, with a yield up to 25 megatons. Smoky became notorious in the 1970s due to the radiation exposures received by over three thousand servicemen who were brought in as part of the Desert Rock exercises to conduct maneuvers in the vicinity of ground zero shortly after the test. This led to Congressional inquiries and epidemiological evaluation of the affected veterans. A 1980 study of the 3224 participants found a significantly elevated number of leukemia cases. Ten cases of leukemia were found, compared to the expected base number for a similar unexposed population of four. NTS, Nevada. 31 August 1957