| Operation Ivy | |
|---|---|
  Operation Ivy test detonations ofMike (top) andKing (bottom), sped up | |
 | |
| Information | |
| Country | United States |
| Test site |
|
| Period | 1952 |
| Number of tests | 2 |
| Test type | dry surface, free air drop |
| Max. yield | 10.4megatonnes of TNT (44 PJ) |
| Test series chronology | |
Operation Ivy was the eighth series ofAmericannuclear tests, coming afterTumbler-Snapper and beforeUpshot–Knothole. The two explosions were staged in late 1952 atEnewetak Atoll in thePacific Proving Ground in theMarshall Islands.
The Operation Ivy test series was the first to involve a hydrogen bomb rather than an atomic bomb, further to the order of PresidentHarry S. Truman made on January 31, 1950, that the US should continue research into all forms of nuclear weapons. The bombs were prepared by theUS Atomic Energy Commission and Defense Department aboard naval vessels, and were capable of being detonated remotely from the control shipUSSEstes.[1]
The firstIvy shot, codenamedMike, was the first successful full-scale test of a multi-megatonthermonuclear weapon ("hydrogen bomb") using theTeller-Ulam design. Unlike later thermonuclear weapons,Mike useddeuterium as its fusion fuel, maintained as a liquid by an expensive and cumbersomecryogenic system. The bomb was detonated on November 1, 1952, onElugelab Island yielding 10.4megatons, almost 500 times the yield of the bomb dropped onNagasaki, resulting in the total vaporization of the island. Eight megatons of the yield were from fast fission of the uranium tamper, creating massive amounts of radioactive fallout. The detonation left an underwater crater 6,240 ft (1.9 km) wide and 164 ft (50 m) deep where Elugelab Island had been. Following this successful test, theMike design was weaponized as theEC-16, but it was quickly abandoned for solid-fueled designs after the success of theCastle Bravo shot two years later.
The outcome of the test was reported to incoming presidentEisenhower by Atomic Energy Commission Chairman,Gordon Dean, as follows: “The island of Elugelab is missing!”[citation needed]
FourUSAFF-84G Thunderjets equipped with filters were flown through themushroom cloud's stem to collectradiochemical samples for analysis. "Red Flight" LeaderVirgil K. Meroney of the nascent1211th Test Squadron flew into the stem of the explosion first. In five minutes, he had gathered all the samples he could, and exited. Jimmy Priestly Robinson, age 28,[2][3][4] a captain with the561st Fighter-Day Squadron, was lost near the end of his mission. After re-emerging from the cloud, both he and hiswingman, pilot Captain Bob Hagan, encountered difficulties picking up rendezvous and runwaynavigational beacons due to "electromagnetic after effects" of the detonation.[3] Robinson hit an area of severe turbulence, entering a spin and barely retaining consciousness. He regained control of his plane at 20,000 feet, but the electromagnetic storm had disrupted his instruments. In rain and poor visibility, without working instruments, Hagan and Robinson were unable to find theKB-29 tanker aircraft to refuel.[2][5]: 96 By the time they were successful in finding the signal, they were dangerously low on fuel, and before reaching the runway on Enewetak, both had depleted their reserves. Hagan made a successfuldead-stick landing on the runway, but Robinson was too far out and attempted to ditch.[3] His jet crashed and sank 3.5 miles short of the island.[2][4][3] Robinson's plane flipped and his body was never found.[2] Approximately a year after his disappearance, he was awarded a posthumousDistinguished Flying Cross for his service.[6][3] In 2002, amemorial stone at Virginia'sArlington National Cemetery was erected.
As a result of the collection of samples from the explosion byU.S. Air Force pilots, scientists found traces of the isotopesplutonium-246 andplutonium-244, and confirmed the existence of the predicted but undiscovered elementseinsteinium andfermium.[2]
The second test,King, fired the highest-yield (500 kilotons)[7] nuclear fission (A-bomb) weapon to date using onlynuclear fission (no fusion norfusion boosting). This test used an unretarded free-fall bomb from a B-36 bomber. The bomber suffered minor heat and blast damage and safely returned to base. This "SuperOralloy Bomb" was intended as a backup to the earlier "Mike" test, if the fusion weapon had failed.
| Name[note 1] | Date time (UT) | Localtime zone[note 2][8] | Location[note 3] | Elevation + height[note 4] | Delivery,[note 5] Purpose[note 6] | Device[note 7] | Yield[note 8] | Fallout[note 9] | References | Notes |
|---|---|---|---|---|---|---|---|---|---|---|
| Mike | October 31, 1952 19:14:59.4 | MHT (11 hrs) | Elugelab (Flora), Enewetak Atoll11°39′57″N162°11′21″E / 11.66573°N 162.18928°E /11.66573; 162.18928 (Mike) | 2 m (6 ft 7 in) + 8 m (26 ft) | dry surface, weapons development | "Sausage" w/TX-5 primary | 10.4 Mt | [9][10][11][12] | Megaton ("M" as in Mike) device. First true experimental H-bomb, usedcryogenicdeuterium; became TX-16 weapon. Elugelab completely cratered. | |
| King | November 15, 1952 23:30:00.0 | MHT (11 hrs) | Runit (Yvonne), Enewetak Atoll11°33′32″N162°20′43″E / 11.55878°N 162.34541°E /11.55878; 162.34541 (King) | 0 + 450 m (1,480 ft) | free air drop, weapons development | Mk-18F SOB | 500 kt | [9][10][11][12] | Kiloton ("K" as in King) device. Aka Super oralloy bomb (SOB), used 4critical masses of U235. Largest pure fission device; also tested chain safety device. |
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In the video gameSid Meier's Civilization VI, Operation Ivy is a late game project that the player can construct at one of their cities. Completing the project allows the player to construct thermonuclear devices, which are more powerful than nuclear devices (which are the game's version of an atomic bomb).
In the video gameSid Meier's Civilization VII, Operation Ivy is a late game project that the player can construct at one of their cities. Completing the project is the victory condition for the Military Legacy Path in the Modern Age.
There was an American punk rock band calledOperation Ivy, named after the real-life nuclear tests.
