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US Archive
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Trinity
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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 splendor of the Mighty One..I am become Death, The shatterer of Worlds". Article on rapatronic photography.
AI Colourized
| Rapatronic
| Preperation
| Press Tour
| Aerial g-zero
| Ground zero
| JRO quote
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Littleboy-Hiroshima |Alberta|
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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 immersion 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 enriched uranium used, only 760 grams (1.2%) actually fissioned before the bomb blew itself to pieces. Clip soundtrack - In Flagrante Delicto, by SPK.
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Fatman-Nagasaki |Alberta|
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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 super-critical 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 were killed outright by the bombing at Nagasaki, with about 25,000 injured.
Loading & Prep
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Able - |Crossroads|
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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 severely 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.
View 2
| Aftermath
| High speed 1
| High speed 2
| Target Fleet
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Baker - |Crossroads|
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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.
Stem Formation HD
| News Reel
| Aftermath
| Aerial View
| High Speed
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X-Ray - |Sandstone|
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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 powerful weapon test to date. The success of X-Ray Sandstone caused the cancellation of the fourth shot which probably contained a solid pit. The underpopulated 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. | |
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Yoke - |Sandstone|
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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 Wilson Cloud can be clearly seen, the result of the compression and rarefaction of the air at the shockfront of the blast.
View 2
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Zebra - |Sandstone|
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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.
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Dog - |Greenhouse|
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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). Article on rapatronic photography.
Rapatronic 1
| Rapatronic 2
| View 4
| Assembly and prep
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Easy - |Greenhouse|
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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.
View 2
| Assembly and prep
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George - |Greenhouse|
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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.
View 2
| View 3
| Fireball
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Item - |Greenhouse|
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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.
View 2
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Baker - |Buster|
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Date: 18:04 UTC 28/10/1951
Type: Airdrop @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.
View 2
| View 3
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Charlie - |Buster|
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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. | |
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Dog - |Buster|
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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.
View 2
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| View 4
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Easy - |Buster|
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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. The Mk-7 used a far more aerodynamic drop case than previous stockpile weapons, as it was designed for high speed low level delivery. Easy was first nuclear test dropped from a jet aircraft.
Initial fireball
| Wide view
| Aerial
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Sugar - |Jangle|
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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.
View 2
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Uncle - |Jangle|
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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.
Wide angle
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Able - |Tumbler|
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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.
View 2
| View 3
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Baker - |Tumbler|
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Date: 12:00 UTC 15/04/1952
Type: Airburst @340m
Yield: 1 Kt
The Baker device was identical to the Able device tested 14 days earlier. 45 weapons effects experiments were
conducted by the DOD during the shot. AFSWC activities involved cloud sampling, cloud tracking, courier service, aerial surveys, and the actual airdrop of the device. About 170 personnel from the Strategic Air Command observed the shot from B-50 aircraft flying over the test area. Like during shot Able, no formal military exercises were conducted during the test.
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Charlie - |Tumbler|
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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.
Ground Effects
| Wide View
| Troop view
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Dog - |Snapper|
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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.
Troops
| Wide View
| Initial fireball
| Fireball
| Fireball 2
| Ground Zero
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Easy - |Snapper|
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Date: 12:15 UTC 07/05/1952
Type: Tower @90m
Yield: 12 Kt
This device (code named BROK-1) was a test of the TX-12, a Mk-12 bomb prototype. The Mk-12 was intended to be a slender, lightweight tactical bomb that could be carried externally by high speed fighter-bombers. It set a record at the time for size and weight, with an implosion system diameter of 56cm weighing only 250 kg (a modest improvement over the Mk-7), yet retained good compression and efficiency. The total device weight was 283 kg, with a predicted yield of 9 kt. It was postponed one day due to unfavorable weather conditions. No formal military exercises were conducted with the shot, however, 1,000 personnel from Camp Desert Rock observed the shot from the Control Point at Yucca Pass.
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Fox - |Snapper|
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Date: 12:00 UTC 25/05/1952
Type: Tower @90m
Yield: 11 Kt
This LASL device (code named XR1) used a Mk-5 bomb assembly. The test was intended to gather data on the initiation time vs yield curve; it also served as a calibration test of the TOM polonium-beryllium internal neutron initiator. The test device had a diameter of 102 cm and weighed 1,225 kg, the predicted yield was 15-18 kt. The device misfired on its first attempt and had to be further postponed due to unfavorable weather conditions. The cloud reached an altitude of 12,500 meters and drifted north into Utah. 1,450 military personnel observed the shot as part of Exercise Desert Rock IV.
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George - |Snapper|
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Date: 11:55 UTC 01/06/1952
Type: Tower @90m
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. | |
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How - |Snapper|
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Date: 11:55 UTC 05/06/1952
Type: Tower @90m
Yield: 14 Kt
This device (code named Scorpion) was designed in part by Ted Taylor. Snapper How was the first test to use a
beryllium neutron reflector/tamper, which would become standard in later weapons. The test device used the same 56 cm implosion system as Snapper Easy, but the lightweight tamper cut 36 kg off the implosion system weight. Predicted yield was 11 kt. How was originally scheduled to be fired on May 27 but was postponed due to unfavorable weather conditions. The cloud reached an altitude of 12,740 meters. The cloud dispersed in several directions. The lower portion moved in a northwestern direction while the upper portion moved to the northeast.
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