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 the total of prior nuclear explosions in the Pacific Ocean. 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.
Aerial shot of the explosion during Hardtack I Poplar. Martin RB-57D in the foreground.
Operation Hardtack I Cactus shot Crater on Runit Island
The Umbrella blast on June 9 with the SS Michael Moran in front.
The Pacific Proving Grounds was the name given by the United States government to a number of sites in the Marshall Islands and a few other sites in the Pacific Ocean at which it conducted nuclear testing between 1946 and 1962. The U.S. tested a nuclear weapon on Bikini Atoll on June 30, 1946. This was followed by Baker on July 24, 1946.
The United States began using the Marshall Islands as a nuclear testing site beginning in 1946.
The "Baker" shot of Operation Crossroads in 1946 was an underwater shot.
After the Ivy Mike shot, only a large crater (at left) remained of the island of Elugelab.