Fact Sheet
Public Affairs Office
Washington, D. C. 20305
HARDTACK was the designation given to the atmospheric nuclear weapon test conducted by the United States in the Pacific Ocean and in Nevada in 1958. Operation HARDTACK I was a series of 35 tests, all but two of which were detnonated at Enewetak and Biking atolls in the Marshall Islands, the Atomic Energy Commission's (AEC) "Enewetok Proving Ground" (EPG). The other two were detonations at 42 and 76 km above Johnston Island, which lies about 700 nmi (1,296 km) west-southwest of the Hawaiian Islands.
The tests were conducted by a joint military and civilian organization designated Joint Task Force 7 (JTF 7. JTF 7 was a military organizatlon in form but was made up of military personnel, Federal clvlllan employees, and contractors of the Department of Defense (DOD) and the AEC. The commander of this force was the appolnted representative of the AEC and reported also to the Jolnt Chlefs of Staff (JCS) and the Commander in Chief Pacific (CINCPAC)
TEST OPERATIONS
During HARDTACK the United States fired as many nuclear devices (35) as had been fired in all prior Pacific Ocean tests. Not only was the total number of shots in HARDTACK large but the variety of types was great; land - and water - surface events, underwater detonations and balloon - and rocket - born high-altitude terts were conducted. The following page of this fact sheet lists the names, dates, and locations of the shots.
In a sense, HARDTACK was divided into three parts. The first was aimed at the development of nuclear weapons continuing the type of testing that had taken place at Enewetak and Biktni during the early and mld-1950s. In these tests, the AEC weapon development laboratories (Los Alamos Scientific Laboratory and the University of Californla Radiatlon Laboratory) detonated their experimental devices with the DOD providing support and conducting experimental that did not interfere with the AEC Activities.
The second part sponsored by DOD, consisted of the underwater test shots, WAHOO and UMBRELLA, the first in the open ocean and the second within the lagoon at Enewetak. The purpose of these tests was to improve the understanding of the effects of underwater explosions on Navy ships and material. These tests could be considered as the continuation of BAKER test of the CROSSROADS series at Bikini in 1946 and the WIGWAM test 500 nmi (927) km) off the U.S. West Coast in 1955.
* Formerly Eniwetok. The spelling of Marshall Island place names has changed in recent years in order to more accurately render the sounds of the Marshall Island names using English spelling.
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