Operation Ivy

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This article is about the nuclear test. For the ska-punk band named after it, see Operation Ivy (band).

The mushroom cloud from the Mike shot.

Operation Ivy was the eighth series of American nuclear tests, coming after Tumbler-Snapper and before Upshot-Knothole. The purpose of the tests were to help upgrade the U.S. arsenal of nuclear weapons, in response to the Soviet nuclear weapons program. The two explosions were staged in late 1952 at the Pacific Proving Ground in the Marshall Islands.

The first device, codenamed Mike, was notable for being the first successful test of a multi-megaton thermonuclear weapon design (the Teller-Ulam design), usually considered the world's first hydrogen bomb test. It used liquid deuterium as its fusion fuel, kept cold with an expensive and cumbersome cryogenic system. Too unwieldy to be deployed as a weapon, it was built to demonstrate the power and possibility of using nuclear fusion as a principle for larger-yield nuclear weapons than previously possible. It was detonated on Elugelab Island in the Enewetak atoll of the Marshall Islands. It yielded 10.4 megatons of explosive power, almost 500 times the power of the bomb that was dropped on Nagasaki. 8 megatons of the yield was from fast fission of the uranium tamper. The detonation obliterated Elugelab, leaving an underwater crater 6,240 ft (1.9 km) wide and 164 ft (50 m) deep where an island had once been.

The second test, King, was a test of the largest nuclear weapon ever built at the time which utilized only nuclear fission as the source of its energy (it had none of its energy added from fusion or fusion boosting). It was dubbed the "Super Oralloy Bomb", and was intended as a backup if the fusion weapon was a failure. It had a yield of 500 kilotons, 25-40 times more powerful than the weapons dropped during World War II.

Ivy Test Blasts
Test Name	Date	Location	Yield	Note
Mike	1 November, 1952	Elugelab Island, Eniwetok	10.4 megatons	First hydrogen bomb
King	16 November, 1952	Airburst 2,000 feet North of Runit Island, Eniwetok	500 kilotons	Largest pure-fission bomb