Operation Hardtack II was a series of 37

nuclear test Nuclear weapons tests are experiments carried out to determine the performance of nuclear weapons and the effects of their explosion. Nuclear testing is a sensitive political issue. Governments have often performed tests to signal strength. Bec ...

s conducted by the United States in 1958 at the

Nevada Test Site The Nevada National Security Sites (N2S2 or NNSS), popularized as the Nevada Test Site (NTS) until 2010, is a reservation of the United States Department of Energy located in the southeastern portion of Nye County, Nevada, about northwest of ...

. These tests followed the ''

Operation Argus Operation Argus was a series of United States low-yield, high-altitude nuclear weapons tests and missile tests secretly conducted from 27 August to 9 September 1958 over the South Atlantic Ocean. The tests were performed by the Defense Nucle ...

'' series and preceded the ''

Operation Nougat Operation Nougat was a series of 44 nuclear tests conducted (with one exception) at the Nevada Test Site in 1961 and 1962, immediately after the Soviet Union abrogated a testing moratorium, with the US' ''Mink'' test shot taking place the day ...

'' series. With test moratoriums on the horizon, American weapons labs rushed out many new designs. A hard deadline for testing was set at midnight (0000 hrs), 31 October 1958, as negotiations were set to start that day, and the schedule shows it, with 29 tests executed in October, four of them on the last day. One other test was cancelled because weather delays postponed it across the midnight deadline. After the conclusion of Hardtack II, the United States announced a unilateral testing moratorium, which the Soviet Union joined after two last tests on 1 and 3 November. In September 1961, the Soviet Union resumed nuclear testing — including the test of the most powerful nuclear device ever designed, the ''

Tsar Bomba The Tsar Bomba (code name: ''Ivan'' or ''Vanya''), also known by the alphanumerical designation "AN602", was a Thermonuclear weapon, thermonuclear aerial bomb, and by far the most powerful nuclear weapon ever created and tested. The Soviet phy ...

'', in October — and the United States followed suit with ''

''.

Nuclear tests

Tamalpais

The Tamalpais test was conducted in the U12b.02 adit of Rainier Mesa by Lawrence Radiation Laboratory on October 8, 1958. The shot took place in a 394-foot-long hook-shaped drift ending in an unusually large test chamber lined with salt blocks as part of an experiment in preparation for Project Gnome. Additional experiments included measuring permanent tunnel displacement, seismic ground shock measurement, gas sampling by Oak Ridge National Laboratory, and electromagnetic pulse measurement by the Department of Defense Effects Test Group. The detonation of the .072 kiloton device released significant radioactive contamination and damage to the U12 tunnel complex, with radiation levels of 50R/h at the main portal and in the 10,000 R/h range in the tunnel immediately following detonation. The following day, workers reentered the tunnel and triggered a significant hydrogen gas explosion that further damaged the tunnel and injured three workers. Following the tunnel's evacuation, a second hydrogen explosion occurred later the same day.

Adams

Adams was planned to be the final test of Hardtack II, but due to unfavorable winds the shot was never fired. The shot was intended to be a balloon test, and had been fully assembled and raised to firing altitude when it was cancelled. After midnight and the start of the moratorium, the device was lowered to the ground and disassembled. The Soviet Union would continue nuclear testing until 3 November. A 31 October 1958 meeting of the Atomic Energy Commission following the cancellation resulted in the following note:

List of nuclear tests

References

External links

* * * * {{Authority control Explosions in 1958 Hardtack II 1958 in military history 1958 in Nevada 1958 in the environment