|Test site||Pacific Proving Grounds, Enewetak Atoll|
|Number of tests||4|
|Test type||Atmospheric tests|
|Max. yield||225 kilotons of TNT (940 TJ)|
|Previous test series||Operation Ranger|
|Next test series||Operation Buster-Jangle|
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, specifically on islands of the Enewetak Atoll, all of the devices were mounted in large steel towers, to simulate air bursts. This series of nuclear weapons tests were preceded by Operation Ranger and succeeded by Operation Buster-Jangle.
Operation 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's first nuclear test a year and half earlier, the United States had begun stockpiling the new designs before they were actually proven. Thus the success of Operation 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 Islet to test nuclear 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, the George device had a small amount of heavy isotopes of liquid hydrogen (deuterium and tritium) placed at its center. The vast majority of its yield derived from fission. The energy output from the thermonuclear fusion in this test was insignificant in comparison. The "George" device was more like a "boosted" atomic bomb than a thermonuclear one. The small amount of heavy deuterium and tritium in this test fused, but its role was to generate a strong flurry of fast neutrons - ones that sparked more fissions in the uranium nuclei that were present, and which also caused fission in uranium-238 - which does not fission under bombardment with slow neutrons, as does uranium-235.
However, the George test validated the principles which would be used for the first full-scale thermonuclear bomb test, Ivy Mike, one year later, on 1 November 1952, at Enewetak Atoll. Item was the first boosted fission weapon, nearly doubling the normal yield of a similar non-boosted weapon.
The detonations in Operation Greenhouse are listed below:
|Name||Date Time (UT)||Location||Elevation + Height||Delivery||Purpose||Device||Yield||Venting||Notes|
|Dog||April 7, 1951 17:33:57.8||Enewetak, Runit (Yvonne)||2 m (6 ft 7 in) + 91 m (299 ft)||Tower||Weapons development||Mk-6D||81 kt||Proof test of Mark 6, 60 point implosion.|
|Easy||April 20, 1951 17:00:27.1||Enewetak, Enjebi (Janet)||2 m (6 ft 7 in) + 91 m (299 ft)||Tower||Both WE and WD||TX-5D||47 kt||Proof test of Mark 5, 92 point lense implosion system, used as the primary for Ivy Mike. Mock buildings (homes, bunkers, factories) were assembled on Enjebi and Mujinkarikku Island.|
|George||May 8, 1951 20:00:30.7||Enewetak, Ebiriru (Ruby)||2 m (6 ft 7 in) + 62 m (203 ft)||Tower||Weapons development||"Cylinder"||225 kt||Deuterium core, first thermonuke using cylinder/disk design, but most yield from boosted fission.|
|Item||May 24, 1951 17:16:59.3||Enewetak, Enjebi (Janet)||2 m (6 ft 7 in) + 62 m (203 ft)||Tower||Weapons development||45.5 kt||First tritium boosted test.|
|Wikimedia Commons has media related to Operation Greenhouse.|
- Magdi Ragheb: Nuclear, Plasma and Radiation Science – Inventing the future (Web Text), Part I, Chapter 5 (2009): Race for the Super.
- United States Nuclear Tests: July 1945 through September 1992 (Revision 15). Department of Energy, Nevada Operations Office. December 2000. Retrieved 10/26/2013.
- Yang, Xiaoping, Robert North, and Carl Romney (August 2000). CMR Nuclear Explosion Database (Revision 3). SMDC Monitoring Research. Retrieved 10/26/2013.
- Hansen, Chuck (1995). The Swords of Armageddon, Vol. 8. Chukelea Publications (Sunnyvale, CA). ISBN 978-0-9791915-1-0.
- Operation Greenhouse. DNA6043F. Department of Defense (Washington, DC). 1951. Retrieved 10/26/2013.
- A bomb test may be a salvo test, defined as two or more explosions "where a period of time between successive individual explosions does not exceed 5 seconds and where the burial points of all explosive devices can be connected by segments of straight lines, each of them connecting two burial points and does not exceed 40 kilometers in length". Mikhailov, V. N., Editor in Chief. Catalog of World Wide Nuclear Testing. Begell-Atom, LLC.
- An appended number represents a member of a salvo test. They usually all have the same name, like Tub-A, Tub-B, ..., but early on had separate names, so other members are denoted by "(with xyz)".
- Universal Time at the Pacific Proving Ground is 12 hours before local time; UT dates are one day before local date for UT times before 12:00.
- Rough place name and a Latitude/Longitude reference. Some are extremely accurate; others (like airdrops and space blasts) may be quite inaccurate. '~' indicates a likely pro-forma rough location, shared with other tests in that same area.
- Elevation is the ground level at the point directly below the explosion relative to sea level; height is the additional distance added or subtracted by tower, balloon, shaft, tunnel or other contrivance. For air bursts it is the absolute altitude of the explosion disregarding ground level (though the ground level is given for comparison), and for rockets the ground level is "N/A".
- Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, barge and cratering are all disallowed by the Partial Nuclear Test Ban Treaty. Sealed shaft and tunnel are underground, and remained useful under the PTBT.
- Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
- Designations for test items where known, nicknames for individual bombs in quotes.Names are "Mark #" or "B#" for bombs, "W#" for rocket warheads, "X#" for experimental, plus code names like "Piccolo". "Primary" refers to a test of only the primary (fission) stage of a multi-stage bomb.
- Estimated energy yield in tonnes, kilotonnes, and megatonnes (and yes, they are all metric units).
- Emissions to atmosphere, where known. No entry means unknown, probably none if underground and "all" if not; otherwise notation for whether measured on the site only or off the site, and the maximum amount released, in Curies ("Ci") with metric prefixes.
- The short film Operation GREENHOUSE (1951) is available for free download at the Internet Archive [more]
- The short film Joint Task Force 3 Presents Operation GREENHOUSE (1951) is available for free download at the Internet Archive [more]