Operation Upshot–Knothole


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. Grable was a 280mm AFAP 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 Artillery Fired Atomic Projectile AFAP artillery shell was fired, the first two shots by University of California Radiation Laboratory—Livermore, and for testing out some of the thermonuclear components that would be used for the massive thermonuclear series of Operation Castle. One primary device was tested in thermonuclear system mockup assemblies of TX-14, TX-16, and TX-17/TX-24, to examine and evaluate the behaviour of radiation cases and the compression of the secondary geometries by the primary's x-rays prior to full-scale testing during Castle. Following RACER's dodgy performance, the COBRA primary was used in the emergency capability ALARM CLOCK, JUGHEAD, RUNT I, RUNT II thermonuclear devices, as well as in the SHRIMP device. RACER IV was employed as primary for the ZOMBIE, RAMROD and MORGENSTERN devices.

List of tests