Operation Tumbler–Snapper

Operation Tumbler–Snapper was a series of atomic tests conducted by the United States in early 1952 at the Nevada Test Site. The Tumbler–Snapper series of tests followed Operation Buster–Jangle, and preceded Operation Ivy.

The Tumbler phase, sponsored by the Atomic Energy Commission consisted of three airdrops which were intended to help explain discrepancies in the actual and estimated blast shock wave damage noted on previous detonations, and to establish more accurately the optimum height of burst.

The Snapper phase, sponsored by the Department of Defense consisted of one airdrop and four tower shots intended to test various new weapons developments.[1]

The military exercise Desert Rock IV, involving 7350 soldiers, took place during the test series. They trained during the Charlie, Dog, and George shots and observed shot Fox.[2]

United States' Tumbler–Snapper series tests and detonations
Name [note 1] Date time (UT) Local time zone [note 2][3] Location [note 3] Elevation + height [note 4] Delivery,[note 5]
Purpose [note 6]
Device [note 7] Yield [note 8] Fallout [note 9] References Notes
Able April 1, 1952 17:00:07.5 PST (−8 hrs) NTS Area 5 36°47′54″N 115°56′11″W / 36.7983°N 115.9364°W 940 m (3,080 ft) + 240 m (790 ft) free air drop,
weapon effect
Mk-4 1 kt I-131 venting detected, 140 kCi (5,200 TBq) [4][5][6][7][8] U-235 core, same as Ranger/Able.
Baker April 15, 1952 17:29:57.1 PST (−8 hrs) NTS Area 7 37°05′03″N 116°01′13″W / 37.0841°N 116.0203°W 1,280 m (4,200 ft) + 340 m (1,120 ft) free air drop,
weapon effect
Mk-4 1 kt I-131 venting detected, 140 kCi (5,200 TBq) [4][5][6][7][8]
Charlie April 22, 1952 17:30:10.0 PST (−8 hrs) NTS Area 7 37°05′04″N 116°01′16″W / 37.0844°N 116.0211°W 1,280 m (4,200 ft) + 1,050 m (3,440 ft) free air drop,
weapons development
Mk-4 31 kt I-131 venting detected, 4.6 MCi (170 PBq) [4][5][6][7][8] Proof test of new core (?). First blast broadcast live on TV. Desert Rock IV.
Dog May 1, 1952 16:29:59.1 PST (−8 hrs) NTS Area 7 37°05′03″N 116°01′16″W / 37.0841°N 116.0211°W 1,280 m (4,200 ft) + 320 m (1,050 ft) free air drop,
weapons development
TX-7 19 kt I-131 venting detected, 2.9 MCi (110 PBq) [4][5][6][7][8] Tested deuterium (without tritium) gas fusion boosting. Investigate rope trick. Desert Rock IV.
Easy May 7, 1952 12:14:59.3 PST (−8 hrs) NTS Area 1 37°03′11″N 116°06′23″W / 37.053°N 116.1064°W 1,294 m (4,245 ft) + 90 m (300 ft) tower,
weapons development
Mk-12 "BROK-1" 12 kt I-131 venting detected, 1.8 MCi (67 PBq) [4][5][6][7][8] First use of beryllium as tamper.
Fox May 25, 1952 11:59:59.6 PST (−8 hrs) NTS Area 4 37°05′44″N 116°06′23″W / 37.0955°N 116.1064°W 1,300 m (4,300 ft) + 90 m (300 ft) tower,
weapons development
TX-5 "XR1" 11 kt I-131 venting detected, 1.6 MCi (59 PBq) [4][5][6][7][8] Designed to test the initiation/yield curve. Calibration test for TOM polonium/beryllium internal initiator. Desert Rock IV.
George June 1, 1952 11:54:59.8 PST (−8 hrs) NTS Area 3 37°02′53″N 116°01′19″W / 37.048°N 116.022°W 1,229 m (4,032 ft) + 90 m (300 ft) tower,
weapons development
TX-5 "XR-2" 15 kt I-131 venting detected, 2.2 MCi (81 PBq) [4][5][6][7][8] Tested an external betatron initiator that shot x-rays into the core, which induced neutrons by photofission. Desert Rock IV.
How June 5, 1952 11:55:00.3 PST (−8 hrs) NTS Area 2 37°08′19″N 116°07′07″W / 37.1386°N 116.1187°W 1,370 m (4,490 ft) + 90 m (300 ft) tower,
weapons development
TX-12 "Scorpion" 14 kt I-131 venting detected, 2.1 MCi (78 PBq) [4][5][6][7][8] First test to use a beryllium neutron reflector/tamper.
  1. ^ The US, France and Great Britain have code-named their test events, while the USSR and China did not, and therefore have only test numbers (with some exceptions – Soviet peaceful explosions were named). Word translations into English in parentheses unless the name is a proper noun. A dash followed by a number indicates a member of a salvo event. The US also sometimes named the individual explosions in such a salvo test, which results in "name1 – 1(with name2)". If test is canceled or aborted, then the row data like date and location discloses the intended plans, where known.
  2. ^ To convert the UT time into standard local, add the number of hours in parentheses to the UT time; for local daylight saving time, add one additional hour. If the result is earlier than 00:00, add 24 hours and subtract 1 from the day; if it is 24:00 or later, subtract 24 hours and add 1 to the day. All historical timezone data (excepting Johnston Atoll) are derived from here:
  3. ^ Rough place name and a latitude/longitude reference; for rocket-carried tests, the launch location is specified before the detonation location, if known. Some locations 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.
  4. ^ 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, air drop or other contrivance. For rocket bursts the ground level is "N/A". In some cases it is not clear if the height is absolute or relative to ground, for example, Plumbbob/John. No number or units indicates the value is unknown, while "0" means zero. Sorting on this column is by elevation and height added together.
  5. ^ Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, and barge are all disallowed by the Partial Nuclear Test Ban Treaty. Sealed shaft and tunnel are underground, and remained useful under the PTBT. Intentional cratering tests are borderline; they occurred under the treaty, were sometimes protested, and generally overlooked if the test was declared to be a peaceful use.
  6. ^ Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
  7. ^ Designations for test items where known, "?" indicates some uncertainty about the preceding value, nicknames for particular devices in quotes. This category of information is often not officially disclosed.
  8. ^ Estimated energy yield in tons, kilotons, and megatons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie).
  9. ^ Radioactive emission to the atmosphere aside from prompt neutrons, where known. The measured species is only iodine-131 if mentioned, otherwise it is all species. 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, where known, and the measured amount of radioactivity released.
Operation Tumbler–Snapper
Tumbler Snapper rope tricks
Photograph taken milliseconds after detonation of nuclear device from the "Tumbler-Snapper" test series. (The shot tower is faintly visible below fireball; downward spikes are termed "rope tricks".)
CountryUnited States
Test site
  • NTS Areas 5, 11, Frenchman Flat
  • NTS, Areas 1–4, 6–10, Yucca Flat
Number of tests8
Test typefree air drop, tower
Max. yield31 kilotonnes of TNT (130 TJ)
Test series chronology


Bomba atomica
A clip of a mushroom cloud during Operation Tumbler-Snapper. Background color change is photographic artifact; vertical smoke trails allow for making shock wave visible.
  1. ^ Byrnes, V. A. (1953). Flash blindness. Operation SNAPPER. Nevada Proving Grounds, April-June 1952, Project 4.5. School of Aerospace Medicine. Brooks A.F.B. Texas.
  2. ^ "Operation TUMBLER SNAPPER Fact Sheet" (PDF). Defense Threat Reduction Agency. Archived from the original (PDF) on February 18, 2013. Retrieved October 26, 2013. Cite journal requires |journal= (help)
  3. ^ "Timezone Historical Database". iana.com. Retrieved March 8, 2014.
  4. ^ a b c d e f g h Estimated exposures and thyroid doses received by the American people from Iodine-131 in fallout following Nevada atmospheric nuclear bomb tests, Chapter 2 (PDF), National Cancer Institute, 1997, retrieved January 5, 2014
  5. ^ a b c d e f g h Sublette, Carey, Nuclear Weapons Archive, retrieved January 6, 2014
  6. ^ a b c d e f g h Hansen, Chuck (1995), The Swords of Armageddon, Vol. 8, Sunnyvale, CA: Chukelea Publications, ISBN 978-0-9791915-1-0
  7. ^ a b c d e f g h United States Nuclear Tests: July 1945 through September 1992 (PDF) (DOE/NV-209 REV15), Las Vegas, NV: Department of Energy, Nevada Operations Office, December 1, 2000, archived from the original (PDF) on October 12, 2006, retrieved December 18, 2013
  8. ^ a b c d e f g h Yang, Xiaoping; North, Robert; Romney, Carl (August 2000), CMR Nuclear Explosion Database (Revision 3), SMDC Monitoring Research

External links

120th Fighter Squadron

The 120th Fighter Squadron (120 FS) is a unit of the Colorado Air National Guard 140th Wing located at Buckley Air Force Base, Aurora, Colorado. The 120th is equipped with the F-16C/D Fighting Falcon.

The squadron is a descendant organization of the World War I 120th Aero Squadron, established on 28 August 1917. It was reformed on 27 June 1923, as the 120th Observation Squadron, and is one of the 29 original National Guard Observation Squadrons of the United States Army National Guard formed before World War II.

The 120th Fighter Squadron was the first federally recognized Air National Guard unit, receiving this distinction on 30 June 1946. Thus, their motto is, "First in the Air Guard."

140th Wing

The 140th Wing (140 WG) is a unit of the Colorado Air National Guard, stationed at Buckley Air Force Base, Aurora, Colorado. If activated to federal service, the Wing is gained by the United States Air Force Air Combat Command.

The 140th Wing flies F-16C/D/ Falcons and C-21 Learjet. It also carries out 137th Space Warning Squadron (Air Force Space Command) and Civil Engineering (Pacific Air Forces) missions. It has over 1200 personnel.

The 120th Fighter Squadron assigned to the Wings 140th Operations Group, is a descendant organization of the World War I 120th Aero Squadron, established on 28 August 1917. It was reformed on 27 June 1923, as the 120th Observation Squadron, one of the 29 original National Guard Observation Squadrons of the United States Army National Guard formed before World War II.

187th Airlift Squadron

The 187th Airlift Squadron (187 AS) is a unit of the Wyoming Air National Guard 153d Airlift Wing. located at Cheyenne Air National Guard Base, Wyoming. The 187th is equipped with the C-130 Hercules.

191st Air Refueling Squadron

The 191st Air Refueling Squadron (191 ARS) is a unit of the Utah Air National Guard 151st Air Refueling Wing located at Wright Air National Guard Base, Utah. The 191st is equipped with the KC-135R Stratotanker.

2019 Boeing B-17 Flying Fortress crash

On October 2, 2019, a Boeing B-17 Flying Fortress owned by the Collings Foundation crashed at Bradley International Airport, Windsor Locks, Connecticut, United States. Seven of the thirteen people on board were killed, and the other six, as well as one person on the ground, were injured. The aircraft was destroyed by fire, with only the tail and a portion of one wing remaining.

28th Intelligence Squadron

The United States Air Force's 28th Intelligence Squadron is an intelligence unit located at Hurlburt Field, Florida. The 28th Intelligence Squadron is a classic reserve associate unit supporting the 25th Intelligence Squadron conducting airborne intelligence, surveillance and reconnaissance to provide threat warning to Air Force Special Operations Command. The squadron was previously active during World War II in the Pacific Theater, providing photographic support to a very heavy bomber group and in the early years of the Cold War as a photographic processing and interpretation unit for a strategic reconnaissance wing.


A bhangmeter is a non-imaging radiometer installed on reconnaissance and navigation satellites to detect atmospheric nuclear detonations and determine the yield of the nuclear weapon. They are also installed on some armored fighting vehicles, in particular NBC reconnaissance vehicles, in order to help detect, localise and analyse tactical nuclear detonations. They are often used alongside pressure and sound sensors in this role in addition to standard radiation sensors. Some nuclear bunkers and military facilities may also be equipped with such sensors alongside seismic event detectors.


Caesium-137 (13755Cs), or radiocaesium, is a radioactive isotope of caesium which is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nuclear weapons. Trace quantities also originate from natural fission of uranium-238. It is among the most problematic of the short-to-medium-lifetime fission products because it easily moves and spreads in nature due to the high water solubility of caesium's most common chemical compounds, which are salts.

Desert Rock exercises

Desert Rock was the code name of a series of exercises conducted by the US military in conjunction with atmospheric nuclear tests. They were carried out at the Nevada Proving Grounds between 1951 and 1957.

Their purpose was to train troops and gain knowledge of military maneuvers and operations on the nuclear battlefield. They included observer programs, tactical maneuvers, and damage effects tests.

Camp Desert Rock was established in 1951, 1.5 miles (2.4 kilometers) south of Camp Mercury. The site was used to billet troops and stage equipment. The camp was discontinued as an Army installation in 1964.

Groom Mine

Groom Mine, located in Lincoln County, Nevada, first opened in the 1870s. Most mining in the area, mostly of silver chloride ores, had finished by 1874. Groom Mine continued to operate, finally ceasing operations in 1954. By 1956, official recordings of products of the Groom Mining District, which includes Groom Mine, shows that lead was the bulk of minerals harvested, which also included 145,000 troy ounces (4,500 kg) of silver and about 45 troy ounces (1.4 kg) of gold. During World War II, Groom Mine became surrounded by military activity, which continued into the 21st century. In the 1950s, the mine was exposed to fallout from nuclear testing that was being carried out at the Nevada Test Site. During the late 20th century, military activities, including the destruction of a mill and the restriction of access to the mine, continued to affect work there. The United States Government seized the mine under eminent domain from its previous owners in 2015.

Lockheed XF-90

The Lockheed XF-90 was built in response to a United States Air Force requirement for a long-range penetration fighter and bomber escort. The same requirement produced the McDonnell XF-88 Voodoo. Lockheed received a contract for two prototype XP-90s (redesignated XF-90 in 1948). The design was developed by Willis Hawkins and the Skunk Works team under Kelly Johnson. Two prototypes were built (s/n 46-687 and -688). Developmental and political difficulties delayed the first flight until 3 June 1949, with Chief Test Pilot Tony LeVier at the controls. Performance of the design was considered inadequate due to being underpowered, and the XF-90 never entered production.

Nevada Test Site

The Nevada National Security Site (N2S2 or NNSS), previously the Nevada Test Site (NTS), is a United States Department of Energy (DOE) reservation located in southeastern Nye County, Nevada, about 65 miles (105 km) northwest of the city of Las Vegas. Formerly known as the Nevada Proving Grounds, the site was established on January 11, 1951 for the testing of nuclear devices, covering approximately 1,360 square miles (3,500 km2) of desert and mountainous terrain. Nuclear weapons testing at the Nevada Test Site began with a 1-kiloton-of-TNT (4.2 TJ) bomb dropped on Frenchman Flat on January 27, 1951. Over the subsequent four decades, over one thousand nuclear explosions were detonated at the NTS. Many of the iconic images of the nuclear era come from the NTS. NNSS is operated by Mission Support and Test Services, LLC.

During the 1950s, the mushroom clouds, from the 100 atmospheric tests, could be seen from almost 100 mi (160 km) away. The city of Las Vegas experienced noticeable seismic effects, and the mushroom clouds, which could be seen from the downtown hotels, became tourist attractions. St. George, Utah, received the brunt of the fallout of above-ground nuclear testing in the Yucca Flats/Nevada Test Site. Westerly winds routinely carried the fallout of these tests directly through St. George and southern Utah. Marked increases in cancers, such as leukemia, lymphoma, thyroid cancer, breast cancer, melanoma, bone cancer, brain tumors, and gastrointestinal tract cancers, were reported from the mid-1950s through 1980. A further 921 nuclear tests were carried out underground.

From 1986 through 1994, two years after the United States put a hold on full-scale nuclear weapons testing, 536 anti-nuclear protests were held at the Nevada Test Site involving 37,488 participants and 15,740 arrests, according to government records.The Nevada Test Site contains 28 areas, 1,100 buildings, 400 miles (640 km) of paved roads, 300 miles of unpaved roads, 10 heliports, and two airstrips.

Currently, the Mission Support and Test Services (MSTS), the successor of the NSTech, is the civilian contractor for the test site's management and further oversees the overall operations of the test site. The MSTS manages and operates the Nevada Test Site for the National Nuclear Security Administration (NNSA) while The Security Protective Force (SPF) is responsible for providing the safeguards and security to the NNSS.


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Operation Buster–Jangle

Operation Buster–Jangle was a series of seven (six atmospheric, one cratering) 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 (Operation Buster) and Los Alamos National Laboratories (Operation Jangle). As part of Operation Buster, 6,500 troops were involved in the Operation Desert Rock I, II, and III exercises in conjunction with the tests. The last two tests, Operation Jangle, evaluated the cratering effects of low-yield nuclear devices. This series preceded Operation Tumbler–Snapper and followed Operation Greenhouse.

Operation Ivy

Operation Ivy was the eighth series of American nuclear tests, coming after Tumbler-Snapper and before Upshot–Knothole. The two explosions were staged in late 1952 at Eniwetok Atoll in the Pacific Proving Ground in the Marshall Islands.

Peaceful nuclear explosion

Peaceful nuclear explosions (PNEs) are nuclear explosions conducted for non-military purposes. Proposed uses include excavation for the building of canals and harbours, electrical generation, the use of nuclear explosions to drive spacecraft, and as a form of wide-area fracking. PNEs were an area of some research from the late 1950s into the 1980s, primarily in the United States and Soviet Union.

In the U.S., a series of tests were carried out under Project Plowshare. Some of the ideas considered included blasting a new Panama Canal, the use of underground explosions to create electricity, and a variety of geological studies. The largest of the excavation tests was carried out in the Sedan nuclear test in 1962, which released large amounts of radioactive gas into the air. By the late 1960s, public opposition to Plowshare was increasing, and a 1970s study of the economics of the concepts suggested they had no practical use. Plowshare saw decreasing interest from the 1960s, and was officially cancelled in 1977.

The Soviet program started a few years after the U.S. efforts and explored many of the same concepts under their Nuclear Explosions for the National Economy program. The program was more extensive, eventually conducting 239 nuclear explosions. Some of these tests also released radioactivity, including a significant release of plutonium into the groundwater and the polluting of an area near the Volga River. A major part of the program in the 1970s and 80s was the use of very small bombs to produce shock waves as a seismic measuring tool, and as part of these experiments, two bombs were successfully used to seal blown-out oil wells. The program officially ended in 1988.

As part of ongoing arms control efforts, both programs came to be controlled by a variety of agreements. Most notable among these is the 1976 Treaty on Underground Nuclear Explosions for Peaceful Purposes (PNE Treaty). The Comprehensive Nuclear-Test-Ban Treaty of 1996 prohibits all nuclear explosions, regardless of whether they are for peaceful purposes or not. Since that time the topic has been raised several times, often as a method of asteroid impact avoidance.

Rope trick effect

Rope trick is the term given by physicist John Malik to the curious lines and spikes which emanate from the fireball of certain nuclear explosions just after detonation.

Sedan (nuclear test)

Storax Sedan was a shallow underground nuclear test conducted in Area 10 of Yucca Flat at the Nevada National Security Site on July 6, 1962, as part of Operation Plowshare, a program to investigate the use of nuclear weapons for mining, cratering, and other civilian purposes. The radioactive fallout from the test contaminated more US residents than any other nuclear test. The Sedan Crater is the largest human-made crater in the United States and is listed on the National Register of Historic Places.

Strategic Defense Initiative

The Strategic Defense Initiative (SDI) was a proposed missile defense system intended to protect the United States from attack by ballistic strategic nuclear weapons (intercontinental ballistic missiles and submarine-launched ballistic missiles). The concept was first announced publicly by President Ronald Reagan on 23 March 1983. Reagan was a vocal critic of the doctrine of mutual assured destruction (MAD), which he described as a "suicide pact", and he called upon the scientists and engineers of the United States to develop a system that would render nuclear weapons obsolete.

The Strategic Defense Initiative Organization (SDIO) was set up in 1984 within the United States Department of Defense to oversee development. A wide array of advanced weapon concepts, including lasers, particle beam weapons and ground- and space-based missile systems were studied, along with various sensor, command and control, and high-performance computer systems that would be needed to control a system consisting of hundreds of combat centers and satellites spanning the entire globe and involved in a battle that would last only minutes. A number of these concepts were tested through the late 1980s, and follow-on efforts and spin-offs continue to this day.

Under the SDIO's Innovative Sciences and Technology Office, headed by physicist and engineer Dr. James Ionson, the investment was predominantly made in basic research at national laboratories, universities, and in industry; these programs have continued to be key sources of funding for top research scientists in the fields of high-energy physics, supercomputing/computation, advanced materials, and many other critical science and engineering disciplines — funding which indirectly supports other research work by top scientists, and which would be politically impossible to fund outside of the defense budget environment.

In 1987, the American Physical Society concluded that the technologies being considered were decades away from being ready for use, and at least another decade of research was required to know whether such a system was even possible. After the publication of the APS report, SDIs budget was repeatedly cut. By the late 1980s, the effort had been re-focused on the "Brilliant Pebbles" concept using small orbiting missiles not unlike a conventional air-to-air missile, which was expected to be much less expensive to develop and deploy.

SDI was controversial throughout its history, and was criticized for threatening to destabilize the MAD-approach and to possibly re-ignite "an offensive arms race". SDI was derisively nicknamed by Democratic Senator Ted Kennedy as "Star Wars", after the 1977 film by George Lucas. By the early 1990s, with the Cold War ending and nuclear arsenals being rapidly reduced, political support for SDI collapsed. SDI officially ended in 1993, when the administration of President Bill Clinton redirected the efforts towards theatre ballistic missiles and renamed the agency the Ballistic Missile Defense Organization (BMDO). BMDO was renamed the Missile Defense Agency in 2002.

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