Operation Hardtack I

Operation Hardtack I
Hardtack I Oak, an 8.9 megaton explosion.
Information
Country	United States
Test site	Bogallua (Alice), Enewetak Atoll; Eninmen (Tare), Bikini Atoll; Enjebi (Janet), Enewetak Atoll; Johnston Island, Johnston Atoll; Namu (Charlie), Bikini Atoll; Pacific Proving Grounds; Pokon (Irvin), Enewetak Atoll; Runit (Yvonne), Enewetak Atoll; Teiter (Gene), Enewetak Atoll; Yurochi aka Irioj (Dog), Bikini Atoll
Period	1958
Number of tests	35
Test type	air drop, balloon, barge, dry surface, high alt rocket (30–80 km), underwater explosion
Max. yield	9.3 megatons of TNT (39 PJ)
Navigation
Previous test series	Project 58/58A
Next test series	Operation Argus

Operation Hardtack I was a series of 35 nuclear tests conducted by the United States from April 28 to August 18 in 1958 at the Pacific Proving Grounds. At the time of testing, the Operation Hardtack I test series included more nuclear detonations than all prior nuclear explosions in the Pacific Ocean put together. These tests followed the Project 58/58A series, which occurred from 1957 December 6 to 1958, March 14, and preceded the Operation Argus series, which took place in 1958 from August 27 to September 6.

Operation Hardtack I was directed by Joint Task Force 7 (JTF 7). JTF-7 was a collaboration between the military and many civilians, but was structured like a military organization. Its 19,100 personnel were composed of members of the US military, Federal civilian employees, as well as workers affiliated with the Department of Defense (DOD) and the Atomic Energy Commission(AEC).

There were three main research directions. The first was the development of new types of nuclear weapons. This was undertaken by detonating experimental devices created by the AEC’s Los Alamos Scientific Laboratory and the University of California Radiation Laboratory. The DOD performed experiments and tests on these detonations that did not hamper the AEC’s research. The second research direction was to examine how underwater explosions affected materiel, especially Navy ships, and was performed by the DOD. The tests were named Wahoo and Umbrella, the former was conducted in the open ocean whereas the latter in a lagoon. The final avenue of study was to analyze high-altitude nuclear tests in order to refine the detection of high-altitude nuclear tests and investigate defensive practices for combatting ballistic missiles. This research direction was composed of three individual tests and were the first high altitude tests. The individual tests in the series were Orange, Teak, and Yucca. Orange and Teak were known collectively as Operation Newsreel and were rocket boosted. Yucca, however, reached its altitude by being raised by balloons.

Many events and proceedings leading up to Operation Hardtack I, such as previous nuclear testing results and the global political atmosphere, influenced its creation and design. One such historical circumstance was that nuclear radiation concerns were mounting publicly and abroad by 1956. During the 1956 Presidential Election, ending nuclear testing was a campaign issue and nuclear safety was one part of that discussion. At the same time, the Union of Soviet Socialist Republics (USSR) was publicly proposing a moratorium on testing.