Operation Fishbowl was a series of high-altitude nuclear tests in 1962 that were carried out by the United States as a part of the larger Operation Dominic nuclear test program.
Introduction
The Operation Fishbowl nuclear tests were originally to be completed during the first half of 1962 with three tests named Bluegill, Starfish and Urraca. The first test attempt was delayed until June. Planning for Operation Fishbowl, as well as many other nuclear tests in the region, began rapidly in response to the sudden Soviet announcement on August 30, 1961, that they were ending a three-year moratorium on nuclear testing. The rapid planning of very complex operations necessitated many changes as the project progressed. All of the tests were to be launched on missiles from Johnston Island in the Pacific Ocean north of the equator. Johnston Island had already been established as a launch site for United States high-altitude nuclear tests, rather than the other locations in the Pacific Proving Grounds. In 1958, Lewis Strauss, then chairman of the United States Atomic Energy Commission, opposed doing any high-altitude tests at locations that had been used for earlier Pacific nuclear tests. His opposition was motivated by fears that the flash from the nighttime high-altitude detonations might blind civilians who were living on nearby islands. Johnston Island was a remote location, more distant from populated areas than other potential test locations. To protect residents of the Hawaiian Islands from flash blindness or permanent retinal injury from the bright nuclear flash, the nuclear missiles of Operation Fishbowl were launched generally toward the southwest of Johnston Island so that the detonations would be farther from Hawaii.
Urraca was to be a test of about 1 megaton yield at very high altitude (above 1000 km). The proposed Urraca test was always controversial, especially after the damage caused to satellites by the Starfish Prime detonation, as described below. Urraca was finally canceled, and an extensive re-evaluation of the Operation Fishbowl plan was made during an 82-day operations pause after the Bluegill Prime disaster of July 25, 1962, as described below. A test named Kingfish was added during the early stages of Operation Fishbowl planning. Two low-yield tests, Checkmate and Tightrope, were also added during the project, so the final number of tests in Operation Fishbowl was five. Tightrope was the last atmospheric nuclear test conducted by the United States, as the Limited Test Ban Treaty came into effect shortly thereafter.
Research directions
The United States completed six high-altitude nuclear tests in 1958, but the high-altitude tests of that year raised a number of questions. According to U.S. Government Report ADA955694 on the first successful test of the Fishbowl series, "Previous high-altitude nuclear tests: Teak, Orange, and Yucca, plus the three ARGUS shots were poorly instrumented and hastily executed. Despite thorough studies of the meager data, present models of these bursts are sketchy and tentative. These models are too uncertain to permit extrapolation to other altitudes and yields with any confidence. Thus there is a strong need, not only for better instrumentation, but for further tests covering a range of altitudes and yields." There were three phenomena in particular that required further investigation:
The electromagnetic pulse generated by a high-altitude nuclear explosion appeared to have very significant differences from the electromagnetic pulse generated by nuclear explosions closer to the surface. The auroras associated with high-altitude nuclear explosions, especially the auroras that appeared almost instantaneously far away from the explosion in the opposite hemisphere, were not clearly understood. The nature of the possible radiation belts that were initially generated along the magnetic field lines connecting the areas of the auroral displays were also poorly understood. Areas of blackout of radio communication needed to be understood in much more detail since that information would be critical for military operations during periods of possible nuclear explosions. The Fishbowl tests were monitored by a large number of surface and aircraft-based stations in the wide area around the planned detonations and also in the region in the southern hemisphere in the Samoan Islands region, which was known in these tests as the southern conjugate region. Johnston Island is in the northern hemisphere, as were all of the planned Operation Fishbowl nuclear detonation locations. It was known from previous high altitude tests, as well as from theoretical work done in the late 1950s, that high-altitude nuclear tests produce a number of unique geophysical phenomena at the opposite end of the magnetic field line of the Earth's magnetic field.
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![Operation Fishbowl: The red burst southwest of Johnston Island indicates the typical detonation point for the Operation Fishbowl tests, and the blue round spot southeast of Fiji indicates the southern magnetic conjugate region where additional auroras were expected and were actually observed. The southern conjugate region is not directly south of the detonation point since the Earth's magnetic field lines do not run in a geographically north–south direction. Also, the magnetic equator of the Earth in this region is slightly to the south of the geographic equator. The detonation point and southern conjugate region were taken from Figure 3 of planning report ADA469481, which was originally a hand-drawn planning map for the Bluegill test.[6] The map shown here actually indicates the detonation point and southern conjugate point for Starfish Prime. The first Bluegill test failed, and the successful Bluegill Triple Prime test detonated at a point closer to Johnston Island.](https://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Pacific_Fishbowl.png/500px-Pacific_Fishbowl.png?utm_source=en.wikipedia.org&utm_campaign=parser&utm_content=thumbnail)
