US Archive Page - 1 | 2 | 3 | 4 | Program History | Operation History | Testing Database | Image Gallery | Trinity Date: 11:29 UTC 16/07/1945 | Type: Tower @30m | Yield: 21 Kt The worlds first atomic explosion code name Trinity, tested in New Mexico at the Alamogordo Test Range. Intended to prove the new implosion design developed at Los Alamos during the previous year. The 'gadget' was an untested implosion device using 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 poetry of John Donne. The gadget was to be placed in a canister called 'Jumbo', so that if the test failed the plutonium could be recovered. It was not used. Gadget prep | Jumbo | Colour | AI Colourized | High speed 1 | High speed 2 | Press Tour | Aerial g-zero | Ground zero | JRO quote Hiroshima |Alberta| Date: 23:16 UTC 05/08/1945 | Type: Airburst @580m | Yield: 15 Kt 'Little Boy' was dropped on Hiroshima by the Enola Gay piloted by Lt. Col. Paul Tibbets. The design used a gun arrangement to shoot a sub-critical mass of U-235 into a U-235 target forming a super-critical mass and a nuclear detonation. This weapon was not tested prior to the attack as it was a deemed certain to work. A highly inefficient design - of the 64kg of highly enriched uranium used, only 585 grams (0.9%) actually fissioned before the bomb blew itself apart. Once armed, the weapon was extremely unsafe, with a crash or fire potentially causing a full yield explosion. For this reason the bomb was armed in-flight. Approximately 70,000 people were killed as a direct result of the blast. A great number more would later die due to radiation exposure, blast or burn injuries. Loading & Prep | Post mission | Aftermath Nagasaki |Alberta| Date: 01:58 UTC 09/08/1945 | Type: Airburst @503m | Yield: 21 Kt 'Fat Man' was dropped by the B-29 bomber 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 only 24 days previously in the New Mexico desert. A subcritical ball (pit) of plutonium was placed inside a shell of high explosive lenses which compressed the pit to super-critical state and a nuclear explosion. An estimated 40,000 people were killed outright by the bombing at Nagasaki, with about 25,000 injured. Loading & Prep Able - |Crossroads| Date: 21:01 UTC 30/06/1946 | Type: Airburst @160m | Yield: 23 Kt Able, a MK-3A fission bomb (nickname Gilda) was dropped by B-29 'Dave's Dream', the bomb fell 298m short and 600m left of target. The first of two weapons effects tests designed specifically to study how nuclear explosions affected naval vessels. A fleet of 71 surplus and captured ships was anchored in the Bikini Atoll lagoon and used as targets. The USS Nevada was painted bright orange for the tests, this ship served as the target for the test. Over 200 ships, 42,000 men, and 150 aircraft participated in the Crossroads tests. View 2 | Aftermath | High speed 1 | High speed 2 | High speed 3 | Target Fleet Baker - |Crossroads| Date: 21:34 UTC 24/07/1946 | Type: Subsurface @-27m | Yield: 23 Kt Baker was a MK-3A warhead encased in a watertight steel caisson suspended beneath a landing ship. 8 ships were sunk or capsized and 8 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 base surge causing the majority of the damage. Contamination of the lagoon was so severe, that the third 'deep' test was cancelled. A deep water test was later conducted during Operation Wigwam in 1955. More than 50,000 still and 500,000 metres of motion picture film were exposed during Crossroads. Caisson prep | Stem Formation | Stem collapse | News Reel | Aftermath | Aftermath 2 | Aerial View | High Speed X-Ray - |Sandstone| Date: 18:17 UTC 14/04/1948 | Type: Tower @70m | Yield: 37 Kt X-Ray proof-tested a new contiguous tamper-core approach with a 'levitated' core in which the pit was suspended within a 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 pit. X-Ray used a composite plutonium/uranium core and was the most powerful weapon test to date. The success of X-Ray caused the cancellation of the 4th shot which probably contained a solid pit. Enjebi island was closed off to all personnel for 11 days after the shot due to heavy contamination. 50 seconds after the explosion the blast wave reached the ground observers. The cloud reached an altitude of 12km where an ice cap formed. View 2 Yoke - |Sandstone| Date: 18:09 UTC 30/04/1948 | Type: Tower @61m | Yield: 49 Kt The 49kt yield was the largest up until that time and remained so until 1951. The fireball was 1.6km wide, the cloud reached an altitude of 17km. Yoke used an all oralloy (highly enriched uranium) core, with a Type B levitated pit. Oralloy is a shortened version of 'Oak Ridge alloy', referencing the location where it was enriched. Despite the 49kt yield, it was considered an inefficient device. A Wilson Cloud can be seen, the result of the compression and rarefaction of the air at the shockfront of the blast. Nitrate transfer compliation | View 2 Zebra - |Sandstone| Date: 18:04 UTC 14/05/1948 | Type: Tower @70m | Yield: 18 Kt Zebra used Oralloy in a levitated pit. Despite the lower yield than shot Yoke it was relatively more efficient. The cloud rose for two minutes before veering eastward. The cloud had a hollow appearance looking like a smoke ring. Eight drone aircraft conducted cloud sampling missions. The drones and samples were found to be more radioactive then the two previous shots. Men removing the radioactive samples received beta radiation burns on their hands requiring skin grafts. View 2 Baker-1 - |Ranger| Date: 13:52 UTC 28/01/1951 | Type: Airburst @330m | Yield: 8 Kt The Baker-1 device was a 'fractional crit' test. A core with less than one critical mass brought to supercriticality by implosion pressure. For comparison, the Fat Man bomb contained 1.3 critical masses. Baker used a type D pit in a Mk 4 high explosive assembly. Baker saw the first use of the TOM initiator. Located at the center of the plutonium pit, it consisted of layers of beryllium and polonium. When the shock wave arrives it crushes the initiator releasing a burst of neutrons triggering the chain. The TOM design was an improvement of the 'Urchin' initiator used during wartime. The cloud reached an altitude of 10,600m. View 2 Dog - |Greenhouse| Date: 17:33 UTC 07/04/1951 | Type: Tower @91m | Yield: 81 Kt Proof test of the Mk-6 strategic bomb. This was the highest yield test up to that time (superseded by George a month later) evaluating the stockpiled MK 6 weapon with a 'How Double Prime' composite uranium-plutonium core. The explosion lifted 250,000 tons of soil to an altitude of 10km. The Mk-6 had an improved 60 point implosion system (the Mk-4 had 32) that provided greater compression and higher efficiency. The Mk-6 was the first nuclear weapon stockpiled in large numbers by the US with over 1000 being produced. High speed 1 | High speed 2 | View 2 | 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, Easy represented a major weight reduction for bombs of the time. The device weighed 1,224kg with a 101cm diameter, compared to 4,555kg and a 152cm diameter for previous designs. It Used a 92 lens implosion system and a composite plutonium/oralloy core. This design was used as the primary in the first thermonuclear bomb test Ivy Mike 18 months later. The cloud reached 12.4km. Extensive weapon effects were tested on various structures erected on Enjebi and the nearby Mijakadrek Island. View 2 | Assembly and prep George - |Greenhouse| Date: 20:30 UTC 08/05/1951 | Type: Tower @62m | Yield: 225 Kt A purely experimental test device named the CYLINDER. It used an enriched uranium core in a cylindrical implosion system. This was used to ignite a physically seperate quantity of deuterium and tritium. The compression of this material created a burst of 14 MeV 'fast neutrons', significantly increasing the amount of fission in the U-235. The yield of the fusion portion was negligible, but was important in developing the principles for later thermonuclear weapons. The cloud formed three ice caps, each leaving a crystal bell along the stem as they rolled downwards over the main cloud. A blue violet nimbus was visable around the cloud caused by ionisation of the surrounding air. The test nearly tripled the yield of any nuclear device detonated up to that time. View 2 | View 3 | View 4 | Set up Item - |Greenhouse| Date: 18:17 UTC 24/05/1951 | Type: Tower @60m | Yield: 45.5 Kt The first test of the principal of 'boosting'. Using a cryogenic deuterium-tritium mixture 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 increasing efficiency doubling the yield. This allowed the use of less fissile material for the same yield. More significantly this meant a lighter assembly, critical in the ongoing miniturisation of nuclear weapons. View 2 Baker - |Buster| Date: 18:04 UTC 28/10/1951 | Type: Airdrop @340m | Yield: 3.5 Kt Baker had two purposes. To test the Mk-4 bomb assembly without using a uranium tamper, and also to document nuclear explosion phenomena. Dropped by the B-50 'Rosebud' above Area 7 of Yucca flat. Pine needles, leaves and grass were positioned along the blast line to measure the effects of a detonation on forests. Dogs, rats and various fabrics were exposed to determine the effects of the thermal pulse on unprotected surfaces. Flash blindness studies were also conducted, with 17 volunteers aboad a C-17 viewing the detonation through different lenses and goggles. View 2 | View 3 Charlie - |Buster| Date: 15:00 UTC 30/10/1951 | Type: Airburst @350m | Yield: 14 Kt The device used a Mk 4 bomb assembly with a composite uranium-plutonium core. 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 and tires incinerated, but still managed a good landing. One of the T-33 drones was completely burned up in the fireball. View 2 Dog - |Buster| Date: 15:30 01/11/1951 | Type: Airburst @430m | Yield: 21 Kt Dog consisted of Mk 4 bomb assembly with a composite U-235/Pu-239 core. The shot was conducted with troops in field emplacements to simulate a defensive deployment southwest of the shot. They observed the shot from 10km from ground zero, then conducted maneuvers in the area. The shot was fired at high altitude to reduce the amount of local fallout though this would not have reduced the neutron-induced radioactive exposure. View 2 | View 3 | View 4 | Aerial view Easy - |Buster| Date: 16:29 UTC 05/11/1951 | Type: Airburst @400m | Yield: 31 Kt 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 predecessors. The design used a 362kg implosion assembly, with a composite uranium-plutonium core. The deployed 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 dropped from a B-45 Tornado, the first nuclear test to be delivered by a jet aircraft. View 2 | View 3 | View 4 | Aerial 1 | Aerial 2 | Aerial 3 | Cloud development | Time-lapse Sugar - |Jangle| Date: 16:59 UTC 19/11/1951 | Type: surface @1m | Yield: 1.2 Kt The first surface test conducted in the Continental US. Surface tests were not seen again at the NTS until 1962 with Little Feller I & II. The test device ('Johnny') used a Mk-6 bomb assembly with an all uranium core, the test name was mnemonic code for 'surface'. High yield surface bursts were being considered for use as cratering and bunker-busting weapons. The test left a crater 7m deep and 27m wide. Desert Rock II was conducted in conjunction with Sugar, with troops observing the shot at a distance of 8km. Due to intense radioactivity from the ground burst, the maneuvers were conducted at a considerable distance from ground zero. Aerial view x4 | View 2 Uncle - |Jangle| Date: 19:59 UTC 29/11/1951 | Type: surface @-10m | Yield: 1.2 Kt A sub-surface cratering burst identical to Ranger Able, the device ("Frankie") was a scaled down test of a proposed 23Kt penetrating gun-type bunker buster. The name Uncle was mnemonic code for 'underground'. The resulting crater was 16m deep and 80m wide. Desert Rock III was also conducted during Uncle with troopoperations limited due to the intense radiation. Aerial view Able - |Tumbler| Date: 17:00 UTC 01/04/1952 | Type: Airburst @241m | Yield: 1 Kt Previous tests during Operations Sandstone, Greenhouse, and Buster, had revealed anomalies in blast over pressures and arrival times from airbursts, so Tumbler was conducted to gather more data on this. Able was based on the Mk-4 bomb, which was the same size as the original Fat Man bomb, but with special core assemblies to obtain a specific reduced yield. The device used the same U-235 core design first tested in Ranger Able. All three air drops during Tumbler were delivered by Boeing B-50 Superfortress. View 2 | View 3 Baker - |Tumbler| Date: 12:00 UTC 15/04/1952 | Type: Airburst @340m | Yield: 1 Kt Baker used a U-235 core in a Mk 4 based test device identical to Able 14 days earlier. 45 weapons effects experiments were conducted by the DOD during the shot. Activities involved cloud sampling, cloud tracking,aerial surveys, and the actual airdrop of the device. About 170 personnel from the SAC observed from B-50 aircraft flying over the test area. As with Able, no formal military exercises were conducted. Charlie - |Tumbler| Date: 17:30 UTC 22/04/1952 | Type: Airburst @1050m | Yield: 31 Kt A Mk 4 device dropped from a B-50 and detonated at high altitude over area 7 of the NTS. It was the first test to be broadcast live on TV. The same scale height as Tumbler Baker was used to check the applicability Hopkinson-Cranz scaling, used to predict blast effects by scaling the distance from the blast based on the cube root of the explosive charge weight. Mach stem | Press news nob | Wide View | Observers Dog - |Snapper| Date: 16:29 UTC 01/05/1952 | Type: Airburst @316m | Yield: 19 Kt A test of a modified TX-7 weapon previously tested in Buster Easy. New features 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 'rope trick' effect seen caused by the incineration of the mooring cables. During Dog, the 'precursor wave' was first observed. Desert Rock IV was conducted during this and other Tumbler-Snapper shots, with troops starting at a 8km "safe" distance and advancing towards ground zero. Troops | Wide View | Initial fireball | Fireball | Fireball 2 | Ground Zero Easy - |Snapper| Date: 12:15 UTC 07/05/1952 | Type: Tower @90m | Yield: 12 Kt Codename BROK-1, a test of the TX-12, a Mk-12 bomb prototype, and the first use of a beryllium tamper. The Mk-12 was a slender lightweight tactical bomb that could be carried externally by high speed aircraft. It set a record for size and weight, with an implosion system diameter of 56cm weighing only 250 kg, while retaining good compression and efficiency. The device weighed 283 kg. It was postponed one day due to unfavorable weather conditions. No military exercises were conducted during the shot, however 1,000 personnel from Camp Desert Rock observed the shot from Yucca Pass. Fox - |Snapper| Date: 12:00 UTC 25/05/1952 | Type: Tower @90m | Yield: 11 Kt Codename XR1 it used a Mk-5 bomb assembly, 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. It had a diameter of 102cm and weighed 1,225kg. The device misfired on its first attempt and had to be further postponed due to unfavorable weather conditions. The cloud reached 12.5km and drifted north into Utah. 1,450 military personnel observed the shot as part of Exercise Desert Rock IV. George - |Snapper| Date: 11:55 UTC 01/06/1952 | Type: Tower @90m | Yield: 15 Kt Codename XR2, it used a Mk-5 bomb assembly, intended to gather data on initiation time vs yield curves. It used of an external initiator as opposed to an internal one activated by the implosion shockwave. Known as a betatron it used electrons to generate X-rays inducing photo-fission in the core to initiate the chain reaction. The betatron allowed very accurate control of initiation time, increasing efficiency. The test device had a diameter of 100cm and weighed 1,224kg, the cloud reached 11km. 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. How - |Snapper| Date: 11:55 UTC 05/06/1952 | Type: Tower @90m | Yield: 14 Kt Codename Scorpion, How was the first test to use a beryllium neutron reflector/tamper, which become standard in later weapons. It used the same 56cm implosion system as Snapper Easy, but the lightweight tamper cut 36kg off the implosion system. Originally scheduled for May 27th it was postponed due to unfavorable weather conditions. The cloud reached 12.7km, before dispersing in several directions. The lower portion moved in a northwestern direction while the upper portion moved to the northeast. Next page 1 | 2 | 3 | 4