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Trinity

Date: 11:29 UTC 16/07/1945 Type: Tower Yield: 18 Kt The worlds first atomic explosion, New Mexico, at the Alamogordo Test Range, test name Trinity . Intended to prove the new implosion design developed at Los Alamos during the previous year, an early morning thunderstorm delayed the test from its originally scheduled time of 4 a.m. until nearly 5:30 a.m. The "gadget" was an untested implosion device using a plutonium later weaponized becoming the "Fatman" bomb dropped on Hiroshima. The origin of the name Trinity is thought to have been provided by Oppenheimer with reference to the divine Hindu trinity of Brahma, Vishnu and Shiva. Following the Trinity test he is reported to have recited the Bhagavad-Gita, "If the radiance of a thousand suns Were to burst at once into the sky, That would be like the splendour of the Mighty One..I am become Death, The shatterer of Worlds". This clip is a sequence of Rapatronic images showing the first 109 millionths of second after detonation. Rapatronic | Construction | JRO quote

Littleboy-Hiroshima-|Alberta|

Date: 23:16 UTC 05/08/1945 Type: Airburst @580m Yield: 15 Kt Codename "Little Boy", the first atomic weapon used in war was dropped on Hiroshima from the Enola Gay piloted by Lt. Col. Paul Tibbets. The design used a gun arrangement to explosively force a sub-critical mass of uranium-235 and three U-235 rings together into a super-critical mass, initiating a nuclear reaction. This weapon was not tested prior to the attack as it was a considered a conservative design. Once armed, the weapon was extremely unsafe, with a crash, fire or emersion in water causing a full yield explosion. For this reason "Deke" Parsons the weaponeer, placed the cordite in the gun in-flight with no gloves in subzero temperatures. Approximately 70,000 people were killed as a direct result of the blast, and a similar number were injured. A great number more would later die as a result of exposure to the prompt radiation and from fallout. The weapon was highly in-efficient from a design perspective - of 64kg of enrighed uranium used, only 760 grams (1.2%) actually fissioned before the bomb blew itself to pieces.

Fatman-Nagasaki|Alberta|

Date: 01:58 UTC 09/08/1945 Type: Airburst @503m Yield: 21 Kt Codename "Fat-Man", dropped over Nagasaki by the B-29 Bockscar, it was the 2nd and last nuclear weapon to be used in combat. "Fat Man" was an implosion type weapon using plutonium, a design tested 24 days previously in the New Mexico desert. A subcritical sphere of plutonium was placed in the center of a hollow sphere of high explosive with numerous detonators located on the surface of the high explosive, firing simultaneously to produce a powerful implosion resulting in a supercritical condition of the pit and a nuclear explosion. The bomb case was fitted with a huge 230kg aluminum high-drag box fin assembly to slow it's decent and increase stability. A by-product of the "California Parachute", was that a falling Fatman made high-pitched whistle, due to air being forced through the small annular opening around the tail cone of the bomb. By comparison, a falling Little Boy with its more-conventional reinforced box fin tail sounded like a "passing freight train". An estimated 40,000 people we re killed outright by the bombing at Nagasaki, with about 25,000 injured.

Able - |Crossroads|

Date: 21:01 UTC 30/06/1946 Type: Airburst @160m Yield: 23 Kt Able was a "Fat Man" MK-3A fission bomb, dropped by B-29 "Dave's Dream", the bomb fell 298m short and 600m left of target. The USS Gilliam was sunk, and four other vessels were either sunk or severly damaged as a result of the blast. The Crossroads tests were the first nuclear explosions since World War II, and the first weapon tests since Trinity. They were "weapons effects" tests - designed specifically to study how nuclear explosions affect naval vessels, planes, and animals. A fleet of 71 surplus and captured ships was anchored in the Bikini Atoll lagoon in the Marshall Islands and used as targets. The USS Nevada was painted bright orange for the tests, this ship served as the target for the test. Cloud development 1 | Cloud development 2 | Timelapse of Cloud | Target Ships

Baker - |Crossroads|

Date: 21:34 UTC 24/07/1946 Type: Subsurface @-27m Yield: 23 Kt Baker was encased in a watertight steel caisson, and suspended beneath a landing ship. Eight ships were sunk or capsized and eight more were severely damaged. The water column reached 600m wide and 2km high, holding a million tons of water. As water fell back from the stem, it formed a dense highly radioactive cloud called the "base surge", this caused the majority of the damage to the ships. A subsurface detonation was expected to be more destructive than the previous airburst, however the radioactive contamination of the lagoon was so severe, that the third "deep" test was cancelled. Alternate view

X-Ray - |Sandstone|

Date: 18:17 UTC 14/04/1948 Type: Tower @70m Yield: 37 Kt X-Ray proof-tested a new design, replacing the contiguous tamper-core approach with a "levitated" core in which the core was suspended within a larger hollow space within the tamper so that a gap existed between them. The collision between the tamper and core created more efficient compression of the core than the explosive-driven shock in the watime design. X-Ray used a composite plutonium/uranium core and was the most powerfull weapon test to date. The sucess of X-Ray Sandstone caused the cancellation of the fourth shot which probably contained a solid pit. The unpopulated islands west of the explosion were heavily contaminated; Enjebi was closed off to all personnel eleven days after the shot. The fireball lasted for 20 seconds. 50 seconds after the explosion the blast wave reached the ground observers. When the cloud reached an altitude of 12,000 meters and ice cap was seen to form. The cloud reached a maximum altitude of 9 kilometers 12 to 13 minutes after the explosion.

Yoke - |Sandstone|

Date: 18:09 UTC 30/04/1948 Type: Tower @61m Yield: 49 Kt Yoke was detonated just before sunrise after being postponed for one day due to unfavorable winds. The 49 kiloton yield was the largest up until that time and remained so until 1951. Ten seconds after the blast the fireball was 1.6 kilometers wide. The cloud reached an altitude of 17,000 meters. Yoke used an all-oralloy core, with a Type B levitated pit. Despite the 49 kiloton yield, it was considered an inefficient device. A Prandtl-Glauert singularity, a result of the compression and rarefaction of the air at the shockfront can be clearly seen.

Zebra - |Sandstone|

Date: 18:04 UTC 14/05/1948 Type: Tower @70m Yield: 18 Kt The Zebra device used highly enriched uranium (Oralloy) in a levitated pit. Despite its lower yield than shot Yoke it was relatively more efficient. The cloud rose straight up for two minutes before veering eastward. Observers stated that the cloud had a hollow appearance and looked like a smoke ring. Eight drone aircraft took part in cloud sampling missions, each making three passes. The drones and samples were found to be more radioactive then the two previous shots. Three men working on removing the radioactive samples from the plane received dangerous beta radiation burns on their hands which required skin grafts. Alternate views: 1 | 2

Dog - |Greenhouse|

Date: 17:33 UTC 07/04/1951 Type: Tower @91m Yield: 81 Kt Dog was a proof test of the Mk-6 strategic bomb. This was the highest yield test up to that time (superseded by George a month later), and evaluated the stockpiled MK 6 weapon with a "How Double Prime" composite uranium-plutonium core. The cockpit of an XB-47 weapons effects aircraft exposed to Greenhouse dog became intensely heated with the metal in the cockpit becoming too hot to touch. The explosion lifted 250,000 tons of soil to an altitude of approximately 10,500m. The Mk-6 had an improved 60 point implosion system (the Mk-4 had a 32 point system) that provided greater compression and higher efficiency. The Mk-6 was the first nuclear weapon stockpiled in large numbers by the U.S. (over 1000 eventually produced). Alternate view | Assembly and prep

Easy - |Greenhouse|

Date: 18:26 UTC 20/04/1951 Type: Tower @91m Yield: 47 Kt Proof test of the Mk-5 bomb, shot Easy represented a major weight reduction for implosion bombs of the time. The device weighed 1224kg with a 101cm diameter, compared to 4.5 metric tonnes and a 152cm diameter for previous designs. It Used a 92 point lens implosion system and a composite plutonium/oralloy core. This design was used as the primary or trigger in the first thermonuclear bomb test, Ivy Mike 18 months later. The cloud reached 12,496m. Extensive weapon effects were tested on various structures erected on Enjebi and the nearby Mijakadrek Island. Assembly and prep

George - |Greenhouse|

Date: 20:30 UTC 08/05/1951 Type: Tower @62m Yield: 225kt George was an purely experimental test device named the CYLINDER. It consisted of an enriched uranium core using a unique cylindrical implosion system. This was used to ignite a physically seperate quantity of deuterium and tritium. The yield of the fusion portion of the test was negligible, but was important in developing the principles required for the later successful thermonuclear weapons. The cloud formed three ice caps in close succession; each was left behind as a shining crystal bell along the stem. When the fireball was at it's zenith, a translucent blue violet nimbus was clearly visable caused by ionisation of the surrounding air. Fireball

Item - |Greenhouse|

Date: 18:17 UTC 24/05/1951 Type: Tower @60m Yield: 45.5 Kt Item was the first test of the principal of "fusion boosting". Using a cryogenic deuterium-tritium mixture in a cavity inside the HEU core which was compressed and heated by the implosion, undergoing a limited fusion reaction. These thermonuclear reactions injected high energy neutrons into the core greatly increasing efficiency of the fission reaction and subsequently the yield. The boosting approximately doubled the yield over its expected unboosted value. This development allowed the use of less of the expensive fissile material for the same yield. More significantly this meant a lighter assembly, critical is the ongoing miniturisation of nuclear weapons.

Baker - |Buster|

Date: 18:04 UTC 28/10/1951 Type: Tower @340m Yield: 3.5 Kt The Baker shot had two purposes. To test the Mk-4 bomb assembly without using a uranium tamper, and also to document basic nuclear explosion phenomena. The bomb was airdropped by the B-50 “Rosebud” at 7:02 local time 340 meters above Area 7 of Yucca flat. Pine needles, leaves and grass were positioned along the blast line to measure the effects of a nuclear detonation on forests. Dogs, rats and various fabrics were exposed to determine the effects of the thermal pulse on unprotected skin. Flash blindness studies were also conducted, with 17 volunteers aboad a C-17 viewing the detonation through a variety of different lenses and goggles. Blindness Testing

Charlie - |Buster|
	Date: 15:00 UTC 30/10/1951 Type: Airburst @350m Yield: 14 Kt Charlie was airdropped from a B-50 over Yucca flats and was the 8th NTS shot. A B-17 sample drone caught in the fireball had most of its fabric control surfaces, tires and wiring incinerated, but still managed a good landing. One of the T-33 drones that went into the cloud also got caught and was completely burned up in the fireball.

Dog - |Buster|

Date: 15:30 01/11/1951 Type: Airburst @430m Yield: 21 Kt The Dog shot was conducted with troops from the 188th Airborne, 127th Engineer Battalion, and the 546th Field Artillery Battalion. The troops dug field emplacements to simulate a defensive deployment southwest of the shot location. They observed the shot from a point six miles from ground zero, and then conducted maneuvers in the area. The shot was fired at high altitude to reduce the amount of local fallout thought this would not have reduced the neutron-induced radioactive exposure. Additional Views : 1 | 2 | 3 | 4 | 5 | 6

Easy - |Buster|

Date: 16:29 UTC 05/11/1951 Type: Airburst @400m Yield: 31 Kt Easy was a test of the TX-7E , a Mk-7 bomb prototype. With a weight of only 816kg and a diameter of 76cm this bomb represented a drastic size reduction over its Fat Man-size predecessors. The design used a 362kg assembly of high explosive, with a composite uranium-plutonium core. The predicted yield was 22-35 kt. Additional Views : 1 | 2 | 3

Sugar - |Jangle|
	Date: 16:59 UTC 19/11/1951 Type: surface @1m Yield: 1.2 Kt This was the only surface test ever conducted in the United States proper, although sub-surface shots were subsequently fired at NTS that produced surface craters. It was Mk-6 bomb using an all uranium core, the test name was a mnemonic code for "surface". The test left a crater 7m deep and 27m wide.

Uncle - |Jangle|

Date: 19:59 UTC 29/11/1951 Type: surface @-10m Yield: 1.2 Kt A sub-surface cratering burst identical to the Ranger Able device, was a scaled down test of a proposed 23Kt penetrating gun-type bunker buster. The test name was mnemonic code for "underground". The resulting crater was 16m deep and 80m wide. Desert Rock III was also conducted in conjunction with Uncle with troops observing the shot from a distance of 8Km, they did not closely approach ground zero due to intense local radiation.

Able - |Tumbler|

Date: 17:00 UTC 01/04/1952 Type: Airburst @241m Yield: 1 Kt Previous tests had revealed unexpected anomalies in blast over pressures and arrival times from airbursts, so Tumbler was conducted to gather detailed data on these effects. Able was based on the Mk-4 bomb, which was essentially the same size as the original Fat Man bomb, but with special core assemblies to obtain a specific reduced yield. The test device used the same U-235 core design first tested in Ranger Able. This design had become something of an experimental benchmark due to its reliability and low yield.

Charlie - |Tumbler|
	Date: 17:30 UTC 22/04/1952 Type: Airburst @1050m Yield: 31 Kt Charlie was a 31Kt MK4 device dropped from a B-50 and detonated at high altitude over area 7 of the Nevada Test site. The predicted yield was 40-60 kt and was the first to be broadcast live on television. Cloud Development

Dog - |Tumbler|

Date: 16:29 UTC 01/05/1952 Type: Airburst @316m Yield: 19 Kt Dog was a test of a modified TX-7 weapon (previously tested in Buster Easy). New features tested included deuterium gas fusion boosting, external initiation, and the use of beryllium neutron reflector/tampers. Experiments calibrated the TOM internal neutron initiator, and explored the curious "rope trick" effect seen with cable moored test devices. The Desert Rock IV field exercise was conducted during this and other Tumbler-Snapper shots, with troops starting at a 5 mile "safe" distance and advancing towards ground zero. Fireball | Cloud Development | Wide Angle

George - |Snapper|

Date: 11:55 UTC 01/06/1952 Type: surface @91m Yield: 15 Kt The George device used a Mk-5 bomb assembly and was intended to gather additional data on the initiation time vs yield curve. A device used of an external initiator as opposed to an internal one activated by the implosion shockwave. This device known as a betatron used electrons to generate high energy X-rays inducing photo-fission in the core to initiate the chain reaction. The betatron allowed very accurate control of initiation time. The test device had a diameter of 100cm and weighed 1224kg, the cloud reached 11,000m. The shot was postponed due to unfavorable weather conditions, and was also moved to a different area of the Nevada Test Site due to residual radiation from the previous shots Easy and Fox.

Mike - |Ivy|

Date: 19:14 UTC 31/10/1952 | Type: Groundburst | Yield: 10.4 Mt The device detonated in the Mike shot, called the Sausage, was the first H-Bomb ever tested, built upon the Teller-Ulam principles of staged radiation implosion. The 10.4Mt device used two stages, with a fission bomb as the primary, and a secondary stage of liquid deuterium fuel in a cylindrical dewar. The dewar was surrounded by a uranium pusher/tamper weighing 5 tons. The steel housing was 2m wide and 6.1m long, with walls 30cm thick. The inside surface of the casing was lined with sheets of lead and polyethylene to form a conduit from the primary to the secondary. The entire device weighed 82 tons making it un-usable weapon. The test island of Eluelab was completely obliterated, the resulting crater was 1.9km wide and 50m deep. 77% (8mt) of the yield was due to fast fission of the natural uranium pusher/tamper making this an extremely "dirty" test showering high levels of radiation over the atoll. The mushroom cloud climbed to 17,000m in only 90 seconds, entering the stratosphere. Within 1 minute it had reached 33,000m, eventually stabilizing at a ceiling of 36,500m. Half an hour after the test the mushroom stretched 96km across. Additional clip using time lapse photography.

King - |Ivy|

Date: 23:30 14/11/1952 Type: Airburst @173m Yield: 500 Kt The device in the King test was dropped by a B-36 bomber flying out of Kwajalein Island. While perhaps not the largest deliverable fission bomb possible at the time, it was certainly pushing close to the practical limit. With such a large amount of enriched uranium (more than 4 critical masses) the bomb was skirting the edge of criticality safety. A 45cm chain made of aluminium and boron filled the central portion of the bomb to absorb neutrons and prevent accidental detonation, it was removed just before the bomb was dropped. The shot was delayed for 24 hours due to bad weather. The live shot was preceded on the 8th November by a dummy run with a mock Mk-18 (T-59) bomb. The target consisted of brightly painted oil drums mounted on pilings arranged in a cross and fitted with radar reflectors to improve accuracy. This target was visible from 40 kilometers away, the bomb was then aimed visually.

Annie - |Upshot-Knothole|

Date: 13:20 UTC 17/03/1953 Type: Tower @90m Yield: 16 Kt Two houses and 50 automobiles were exposed to the shot for the Federal Civil Defense Administration. Members of the media were allowed to observe shot Annie, which was designated as an open shot by the AEC. Most of the reports observed the shot from News Nob, some 12 kilometers south of the shot tower. 20 reporters were selected to accompany the troops in trenches 3.2 km from the blast. 1,700 troops conducted maneuvers around the blast as part of Desert Rock V. Officially a weapons development shot, it tested an experimental device code named XR3. The device was a Mk-5 HE assembly using a Type D pit. The total weight of the device was 1,225 Kg.

Dixie - |Upshot-Knothole|

Date: 15:29 UTC 06/04/1953 Type: Airburst @1830m Yield: 11 Kt B-50 bomber air drop, the detonation was 199m east, and 21m north of the designated ground zero. Dixie was a Mk-5D bomb proof test. The predicted yield was 8-12 kt. This test experimented with lithium deuteride as a means of fusion boosting, hence the mnemonic test name Dixie. Radioactive rain would later fall on Boston following the Dixie shot.

Badger - |Upshot-Knothole|

Date: 12:35 UTC 18/04/1953 Type: Tower @90m Yield: 23 Kt Badger was a test of the TX-16 thermonuclear weapon design, the reduced size cryogenic weapon descended from the Sausage device tested in Ivy Mike. The test device was named Buzzard and used a deuterium gas boosted RACER primary. The expected yield was 35-40 kt. The full scale thermonuclear version of this design was actually deployed on a limited scale for a short time as an EC or (Emergency Capability) weapon in late 1953 and early 1954. The full scale version was never tested though due to the success of solid fuelled weapon designs. Observers were stationed in trenches 3,660 meters southwest of ground zero. Troops began a mock attack on a position 1,830 meters southwest of ground zero after the shockwave had passed. A wind gust blew a portion of the radioactive cloud over several observer trenches, resulting in contamination. Several Marines exceeded the allowable does of 6.0 R/h, some film badges read 7.1 R/h.

Encore - |Upshot-Knothole|

Date: 15:29 08/05/1953 Type: Airburst @1050m Yield: 27 Kt Encore Upshot-Knothole was scheduled for May 7, 1953, but due to inclement weather it was postponed until the following day. The test name was mnemonic code for "Effects". It was one of eleven atomic detonations in a series that took place at the Nevada Proving Grounds (Camp Desert Rock) in 1953. The bomb was a Mk-6 device dropped from a B-50 at a tower target at ground zero. The shot was off target by 33 meters. Troops were entrenched 10 kilometers from ground zero and after the detonation were ordered to advance. Upshot-Knothole tested the radiation implosion systems for the world's first deployable thermonuclear weapons which would be proof-tested in Operation Castle the following year. Alternate View

Grable - |Upshot-Knothole|

Date: 15:30 UTC 25/05/1953 Type: Airburst @159m Yield: 15 Kt The Grable shot was an artillery delivered airburst. The test name was mnemonic code for "Gun". The shell travelled 10,000 meters before detonation 26m west, 41m south, and 7m above the designated burst point. The 280 mm shell used a "gun-type" fission weapon assembly method like the Little Boy bomb. The Mk-9 280 mm shell was 130cm long, weighed 365 kilos, and used oralloy as the fissile material. Air burst detonation was arranged by a time fuse. The Mk-9 device was fired by an enormous 85 ton artillery piece which had a muzzle velocity of 629m/sec, and a range of up to 32 kilometers. More information about the test. 2.66:1 CinemaScope version | Alternate view 1 | Alternate view 2

Climax - |Upshot-Knothole|

Date: 11:14 UTC 04/06/1953 Type: Airburst @406m Yield: 61 Kt Climax was air dropped by a B-36, the shot was 52m west, and 70m north of the designated ground zero. It was a proof test of the Mk-7 high yield, light weight fission bomb. This weapon had a small diameter making it suitable for external carriage by high speed fighter-bombers. The predicted yield of this device was 50-70 kt, the yield of 61kt was the highest of any U.S. continental test up to this time. The Mk-7 was the lightest and most compact implosion bomb design yet developed. The test name was mnemonic code for "Cobra". The composite Cobra primary was later essential in several thermonuclear devices in the Castle test series, namely the Shrimp, Runt 1/2 and Alarm Clock devices. The smoke trails visable in this and other tests are actually left by small rockets just before the detonation to help analyse the blastwave. Alternate view

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Published on: 2005-12-16 (223940 reads)