This silent, raw footage shows the atomic test known as Climax which occurred on June 4, 1953 as part of Operation Upshot Knothole. Operation Upshot–Knothole was a series of eleven nuclear test shots conducted in 1953 at the Nevada Test Site as part of Desert Rock. 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, and for testing out some of the thermonuclear components that would be used for the massive thermonuclear series of Operation Castle. One primary device (RACER) was tested in thermonuclear system mockup assemblies of TX-14, TX-16, and TX-17/TX-24, to examine and evaluate the behavior 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 (as redesigned and proof-tested in the Simon test) was employed as primary for the ZOMBIE, RAMROD and MORGENSTERN devices.
Climax was a test of a boosted MK-7 device, intended to be used as a primary in Castle. Initially it was intended only for the TX-15. After RACER’s inconsistent behavior it was opted for all “emergency capability” devices instead. The bomb detonated 320 ft (98 m) NW of target. Composite implosion system in a Type D pit. Used Cyclotol 75/25 explosive mixture. B-36 bomber air drop, the detonation was 172 feet west, and 232 feet north of the designated ground zero. This was a proof test of the Mk-7 high yield, light weight fission bomb, and dropped from a B-36 bomber. The diameter of the bomb was 30 inches, making it suitable for external carriage by high speed fighter-bombers. The predicted yield of this device was 50-70 kt, and the actual yield (61 kt) was the highest of any U.S. continenetal test up to this time. The Mk-7 was the lightest and most compact implosion bomb design yet developed, and its implosion system – a composite COBRA core in a Type D pit – was later used as a primary in several high yield thermonuclear devices in the Castle test series.
The complete bomb was 30.5 inches wide and 183 inches long, and weighed 1840 lb. The implosion system weighed 900 lb and used the more powerful Cyclotol 75/25 in preference to the Composition B used in most bombs at that time.
Operation Upshot-Knothole exposed exercise personnel to radiation more aggressively than previous tests. Observation by troop formations were conducted at what was calculated to be the minimum safe separation distance, with many personnel being exposed to multiple tests. Under current occupational radiation exposure limits (0.3 rem/week and 5 rem/year) this would would limit maximum exposures to 3.3 rems over the 11 week operation. Approximately three thousand soldiers reached or exceeded this limit, with 84 exceeding the annual limit (the highest recorded exposure was 26.6 rem). These exposures do not produce observable symptoms, they simply increase the lifetime risk of cancer a small amount.
The effect on the downwind civilian population, taken together, was much worse. Uphot-Knothole released some 35,000 kilocuries of radioiodine (I-131) into the atmosphere. This produced total civilian radiation exposures amounting to 89 million person-rads of thyroid tissue exposure (about 24% of all exposure due to continental nuclear tests). This can be expected to eventually cause about 28,000 cases of thyroid cancer, leading to some 1400 deaths.
Camp Desert Rock was established in 1951, 1.5 miles (2.4 kilometers) south of Camp Mercury. The site was used to billet troops and stage equipment. The camp was discontinued as an Army installation in 1964.
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