Operation Greenhouse

Operation Greenhouse was the fifth American nuclear test series, the second conducted in 1951 and the first to test principles that would lead to developing thermonuclear weapons (hydrogen bombs). Conducted at the new Pacific Proving Ground, all of the devices were mounted in large steel towers, to simulate air bursts. Succeeded Operation Ranger

Operation Ranger

Operation Ranger was the fourth American nuclear test series. It was conducted in 1951 and was the first series to be carried out at the Nevada Test Site. All the bombs were exploded in the open air, having been dropped by B-50 bombers....

, Preceded Operation Buster-Jangle

Operation Buster-Jangle

Operation Buster-Jangle was a series of seven nuclear weapons tests conducted by the United States in late 1951 at the Nevada Test Site. Buster-Jangle was the first joint test program between the DOD and Los Alamos National Laboratories. 6,500 troops were involved in the Desert Rock I, II, and III...

.

Greenhouse represented new and aggressive designs for nuclear weapons. The main idea was to reduce the size, weight, and most importantly, reduce the amount of fissile material necessary for nuclear weapons, while increasing the destructive power. With the Soviet Union

Soviet Union

The Union of Soviet Socialist Republics was a constitutionally socialist state that existed in Eurasia from 1922 to 1991. The name is a translation of the , tr. Soyuz Sovetskikh Sotsialisticheskikh Respublik, abbreviated СССР, SSSR. The common short name is Soviet Union, from , Sovetskiy Soyuz...

's first nuclear test just a year and half earlier, the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 had begun stockpiling the new designs before they were actually proven. Thus the success of Greenhouse was vital before the development of thermonuclear weapons could continue.

A number of target buildings, including bunkers, homes and factories were built on Mujinkarikku Island to test weapon effects.

The "George" explosion was the world's first thermonuclear burn, though it was just a test design, unsuitable for weaponization. Shaped like a torus

Torus

In geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with and not touching the circle. Examples of tori include the surfaces of doughnuts and inner tubes. The solid contained by the surface is known as a toroid...

, the "George Device" had a small amount of liquid hydrogen placed at its center. The vast majority of its yield derived from fission; the energy output from fusion was insignificant in comparison. However, it validated the principles which would be used for the first full thermonuclear device test Ivy Mike

Ivy Mike

Ivy Mike was the codename given to the first United States nuclear test of a fusion device, in which a major part of the explosive yield came from nuclear fusion. It was detonated on November 1, 1952 by the United States at on Enewetak, an atoll in the Pacific Ocean, as part of Operation Ivy...

a year later. "Item

Greenhouse Item

Greenhouse Item was an American nuclear test conducted on May 25, 1951 as part of Operation Greenhouse at the Pacific Proving Ground, specifically on the island of Engebi in the Enewetak Atoll. The shot was the first test of a boosted fission weapon, where deuterium-tritium gas injected into the...

" was the first boosted fission weapon

Boosted fission weapon

A boosted fission weapon usually refers to a type of nuclear bomb that uses a small amount of fusion fuel to increase the rate, and thus yield, of a fission reaction. The neutrons released by the fusion reactions add to the neutrons released in the fission, as well as inducing the fission reactions...

, nearly doubling the normal yield of a similar non-boosted weapon.

Greenhouse Test Blasts

Test Name	Date	Location	Yield	Note
Dog	8 April, 1951	Pacific Proving Ground	70 kilotons
Easy	21 April, 1951	Pacific Proving Ground	47 kilotons
George	9 May, 1951	Pacific Proving Ground	225 kilotons	First thermonuclear experiment, deuterium core
Item Greenhouse Item Greenhouse Item was an American nuclear test conducted on May 25, 1951 as part of Operation Greenhouse at the Pacific Proving Ground, specifically on the island of Engebi in the Enewetak Atoll. The shot was the first test of a boosted fission weapon, where deuterium-tritium gas injected into the...	25 May, 1951	Pacific Proving Ground	45.5 kilotons	First bomb with tritium "boosting"