|Place of origin||Soviet Union|
|Designer||Yulii Khariton, Andrei Sakharov, Viktor Adamsky, Yuri Babayev and Yuri Smirnov , Yuri Trutnev, and Yakov Zel'dovich.|
|Mass||27,000 kg (60,000 lb)|
|Length||8 m (26 ft)|
|Diameter||2.1 m (6 ft 11 in)|
|Blast yield||50–58 megatons of TNT (210–240 PJ)|
The Tsar Bomba (Russian: Царь-бо́мба), (code name: Ivan or Vanya), also known by the alphanumerical designation AN602, was a hydrogen aerial bomb, and the most powerful nuclear weapon ever created and tested. Tsar Bomba was developed in the Soviet Union (USSR) by a group of nuclear physicists under the leadership of Igor Kurchatov, an academician of the Academy of Sciences of the Soviet Union.
Tested on 30 October 1961, the scientific result of the test was the experimental verification of calculation principles and multi-stage thermonuclear charges. The bomb was dropped to descent by parachute from a Tu-95V aircraft, and detonated autonomously 4,000 metres (13,000 ft) above the Sukhoy Nos ("Dry Nose") cape of Severny Island, Novaya Zemlya, 15 km (9.3 mi) from Mityushikha Bay, north of Matochkin Strait. The detonation was intended to be secret, but was detected by United States intelligence agencies, via a KC-135A aircraft (Operation SpeedLight) in the area at the time. A secret U.S. reconnaissance aircraft named "Speed Light Alpha" monitored the blast, coming close enough to have its antiradiation paint scorched.
The bhangmeter results and other data suggested the bomb yielded around 58 Mt (243 PJ), which was the accepted yield in technical literature until 1991, when Soviet scientists revealed that their instruments indicated a yield of 50 Mt (209 PJ). As they had the instrumental data and access to the test site, their yield figure has been accepted as more accurate. In theory, the bomb would have had a yield in excess of 100 Mt (418 PJ) if it had included the uranium-238 fusion tamper which figured in the design but which was omitted in the test to reduce radioactive fallout. Because only one bomb was built to completion, that capability has never been demonstrated. The remaining bomb casings are located at the Russian Atomic Weapon Museum in Sarov and the Museum of Nuclear Weapons, All-Russian Scientific Research Institute Of Technical Physics, in Snezhinsk.
AN602 (Tsar Bomba) was a modification of the RN202 project. A number of published books, even some authored by those involved in product development 602, contain inaccuracies that are replicated elsewhere, including wrongly identifying AN602 as RDS-202 or RN202.
In the mid-1950s, the United States (US) had an unconditional superiority over the Soviet Union (USSR) in nuclear weapons, although thermonuclear charges had already been created in the USSR at this time. Also, there were no effective means of delivering nuclear warheads to the US, both in the 1950s and in 1961. The USSR was not therefore able to muster a possible realistic retaliatory nuclear strike against the US.
The production of Tsar Bomba therefore became necessary because of foreign policy and propaganda considerations, to respond to US nuclear blackmail. As an expression of the concept of nuclear deterrence adopted during the leadership of Georgy Malenkov and Nikita Khrushchev, the actual strategic situation in consideration to this concept, for the Soviet Union, as a consequence of the disequilibrium with regards to the Soviet Union vis-à-vis America's nuclear weapons possessions, to the favour of the latter, was that the creation of Tsar Bomba represented a necessitated bluff.
Also on June 23, 1960, the Resolution of the Council of Ministers of the USSR was issued on the creation of a super-heavy ballistic missile N-1 ( GRAU index – 11A52) with a warhead weighing 75 t (74 long tons; 83 short tons) (for a comparative assessment – the weight of the warhead tested in 1964, by the UR-500 ICBM was 14-tonne (14-long-ton; 15-short-ton).
The development of new designs of nuclear and thermonuclear ammunition requires testing. The operability of the device, its safety in emergency situations, and the calculated energy release during an explosion must be confirmed.
Official names: "product 602", "AN602", "Ivan." At present, the difference in names becomes the cause of confusion when AN602 is mistakenly identified with RDS-37 or with PH202 (product 202). (The AN602 was a modification of the RN202. In the correspondence for the RN202, the designation RDS-202, “202,” and “Product B,” were originally used.)
Sometimes the bomb is referred to as RDS-220.
Unofficial names – "Tsar Bomba" and "Kuzkina Mother". The name Tsar Bomba (loosely, Emperor of Bombs) emphasizes that this is the most powerful weapon in history. The name “Kuz'ka's Mother” was inspired by the statement of Khrushchev to then US Vice President Richard Nixon: “We have funds at our disposal that will have dire consequences for you. We will show you Kuz'ka's mother!"
The development of a super-powerful bomb began in 1956 and was carried out in two stages. At the first stage, from 1956 to 1958, it was "product 202", which was developed in the recently-created NII-1011. The modern name of NII-1011 is the "Russian Federal Nuclear Center or the All-Russian Scientific Research Institute of Technical Physics" (RFNC-VNIITF). According to the official history of the institute, the order on the creation of a research institute in the system of the Ministry of Medium Machine Building was signed on April 5, 1955; work at the NII-1011 began a little later.
At the second stage of development, from 1960 to a successful test in 1961, the bomb was called "item 602" and was developed at KB-11 (VNIIEF), V. B. Adamsky was developing, and besides him, the physical scheme was developed by Andrei Sakharov, Yu. N. Babaev, Yu. N. Smirnov, Yu. A. Trutnev.
After the successful test of the RDS-37, KB-11 employees (Sakharov, Zeldovich, and Dovidenko) performed a preliminary calculation and, on February 2, 1956, they handed over to N. I. Pavlov, a note with the parameters for charges of 150 Mt (628 PJ) and the possibility of increasing the power to 1 gigaton of TNT (4 EJ).
After the creation in 1955 of the second nuclear center – NII-1011, in 1956, by a resolution of the Council of Ministers, the center was assigned the task of developing an ultra-high-power charge, which was called "Project 202".
On March 12, 1956, a draft Joint Resolution of the Central Committee of the Communist Party of the Soviet Union (CPSU Central Committee) and the Council of Ministers of the Soviet Union on the preparation and testing of the 202 product was adopted. The project planned to develop a version of the RDS-37 with a capacity of 30 Mt (126 PJ). RDS-202 was designed with a maximum calculated power release of 50 Mt (209 PJ), with a diameter of 2.1 m (6 ft 11 in), a length of 8 m (26 ft), weighing 26 t (26 long tons; 29 short tons) with a parachute system and structurally coordinated with the Tu-95-202 carrier aircraft specially converted for its use. On June 6, 1956, the NII-1011 report described the RDS-202 thermonuclear device with a design power of up to 38 Mt (159 PJ) with the required task of 20–30 Mt (84–126 PJ). In reality, this device was developed with an estimated power of 15 Mt (63 PJ), after testing the products "40GN," "245" and "205" its tests were deemed inappropriate and canceled.
The Tsar Bomba differs from its parent design – the RN202 – in several places. The Tsar Bomba was a three-stage bomb with a Trutnev-Babaev second- and third-stage design, with a yield of 50 Mt. This is equivalent to about 1,570 times the combined energy of the bombs that destroyed Hiroshima and Nagasaki, 10 times the combined energy of all the conventional explosives used in World War II, one quarter of the estimated yield of the 1883 eruption of Krakatoa, and 10% of the combined yield of all nuclear tests to date. A three-stage hydrogen bomb uses a fission bomb primary to compress a thermonuclear secondary, as in most hydrogen bombs, and then uses energy from the resulting explosion to compress a much larger additional thermonuclear stage. There is evidence that the Tsar Bomba had several third stages rather than a single very large one. RDS-202 was assembled on the principle of radiation implosion, which was previously tested during the creation of RDS-37. Since it used a much-heavier secondary module than in the RDS-37, not one, but two primary modules (charges), located on two opposite sides of the secondary module, were used to compress it.   This physical charging scheme was later used in the design of the AN-602, but the AN-602 thermonuclear charge itself (secondary module) was new. The RDS-202 thermonuclear charge was manufactured in 1956, and was planned for testing in 1957, but was not tested and put into storage. Two years after the manufacture of the RDS-202, in July 1958, it was decided to remove it from storage, dismantle and use automation units and charge parts for experimental work (Order No. 277 of the Ministry of Medium Machine Building dated May 23, 1957). The CPSU Central Committee and the Council of Ministers of the USSR adopted a draft Joint Resolution on 12 March, 1956, on the preparation and testing of izdeliye 202, which read:
Adopt a draft resolution of the CPSU Central Committee and the USSR Council of Ministers on the preparation and testing of izdeliye 202.
Paragraphs required for inclusion in the draft resolution:
(a) The Ministry of Medium Engineering (Comrade Avraami Zavenyagin) and the Ministry of Defense of the USSR (Comrade Georgy Zhukov) at the end of the preparatory work for the test of izdeliye 202 to report to the CPSU Central Committee on the situation;
(b) The Ministry of Medium Engineering (Comrade Zavenyagin) to solve the issue of introducing a special stage of protection into the design of izdeliye 202 to ensure disarming of the product in the event of a failure of the parachute system, as well as their proposals reported to the CPSU Central Committee.
Comrades Boris Vannikov and Kurchatov are assigned to edit the final version of this resolution.
In 1960, KB-11 began developing a thermonuclear device with a design capacity of one hundred megatons of TNT (four hundred and eighteen petajoules). In February 1961, the leaders of KB-11 sent a letter to the Central Committee of the CPSU with the subject line "Some questions of the development of nuclear weapons and methods of their use," which, among other things, raised the question of the expediency of developing such a 100 Mt device. On July 10, 1961, a discussion took place in the Central Committee of the CPSU, at which Nikita Khrushchev supported the development and testing of this super-powerful bomb.
To speed up the work on the AN602, it was based on the 202 Project, but was a new project, developed by a different group. In particular, in KB-11, six casings for the Project 202 bomb already manufactured at NII-1011 and a set of equipment developed for the 202 Project testing were used.
AN602 had a "three-stage" design: the first stage is the necessary fission trigger. The second stage was two relatively small thermonuclear charges with a calculated contribution to the explosion of 1.5 Mt (6 PJ), which were used for radiation implosion of the third stage, the main thermonuclear module located between them, and starting a thermonuclear reaction in it, contributing 50 Mt of explosion energy. As a result of the thermonuclear reaction, huge numbers of high-energy fast neutrons were formed in the main thermonuclear module, which, in turn, initiated the fast fission nuclear reaction in the nuclei of the surrounding uranium-238, which would have added another 50 Mt of energy to the explosion, so that the estimated energy release of the AN602 was around 100 Mt.
The test of such a complete three-stage 100 Mt bomb was rejected due to the extremely high level of radioactive contamination that would be caused by the fission reaction of large quantities of uranium-238 fission. During the test, the bomb was used in a two-stage version. A. D. Sakharov, suggested using nuclear passive material instead of the uranium-238 in the secondary bomb module, which reduced the bomb's energy to 50 Mt, and, in addition to reducing the amount of radioactive fission products, avoided the fireball's contact with the Earth's surface, thus eliminating radioactive contamination of the soil and the distribution of large amounts of fallout into the atmosphere.
Many technical innovations were applied in the design of the AN602. The thermonuclear charge was made according to the “bifilar” scheme - the radiation implosion of the main thermonuclear stage was carried out from two opposite sides. These secondary charges produced X-ray compression of the main thermonuclear charge. For this, the second stage was separated into two fusion charges which were placed in the front and rear parts of the bomb, for which a synchronous detonation was required with a difference in initiation of no more than 100 nanoseconds. To ensure synchronous detonation of charges with the required accuracy, the sequencing unit of the detonation electronics was modified at KB-25 (now "Federal State Unitary Enterprise "NL Dukhov All-Russian Scientific Research Institute of Automation")(VNIIA).[better source needed]
The initial three-stage design of Tsar Bomba was capable of yielding approximately 100 Mt through fast fission (3,000 times the size of the Hiroshima and Nagasaki bombs); however, it was thought that this would have resulted in too much nuclear fallout, and the aircraft delivering the bomb would not have had enough time to escape the explosion. To limit the amount of fallout, the third stage and possibly the second stage had a lead tamper instead of a uranium-238 fusion tamper (which greatly amplifies the fusion reaction by fissioning uranium atoms with fast neutrons from the fusion reaction). This eliminated fast fission by the fusion-stage neutrons so that approximately 97% of the total yield resulted from thermonuclear fusion alone (as such, it was one of the "cleanest" nuclear bombs ever created, generating a very low amount of fallout relative to its yield). There was a strong incentive for this modification, since most of the fallout from a test of the bomb would likely have descended on populated Soviet territory.
The first studies on "Topic 242" began immediately after Igor Kurchatov talked with Andrei Tupolev (then held in Autumn 1954). Tupolev appointed his deputy for weapon systems, Aleksandr Nadashkevich, as the head of the Topic. Subsequent analysis indicated that to carry such a heavy, concentrated load, the Tu-95 bomber carrying the Tsar Bomba needed to have its engines, bomb bay, suspension and release mechanisms seriously redesigned. The Tsar Bomba's dimensional and weight drawings were passed in the first half of 1955, together with its placement layout drawing. The Tsar Bomba's weight accounted for 15% of the weight of its Tu-95 carrier as expected. The carrier, aside from having its fuel tanks and bomb bay doors removed, had its BD-206 bomb-holder replaced by a new, heavier beam-type BD7-95-242 (or BD-242) holder attached directly to the longitudinal weight-bearing beams. The problem of how to release the bomb was also solved; the bomb-holder would release all three of its locks in a synchronous fashion via electro-automatic mechanisms as required by safety protocols.
A Joint Resolution of the CPSU Central Committee and the Council of Ministers (Nr. 357-28ss) was issued on 17 March, 1956, which mandated that OKB-156 begin conversion of a Tu-95 bomber into a high-yield nuclear bomb carrier. These works were carried out in the Gromov Flight Research Institute from May to September 1956. The converted bomber, designated the Tu-95V, was accepted for duty and was handed over for flight tests which, including a release of a mock-up "superbomb", were conducted under the command of Colonel S. M. Kulikov until 1959, and passed without major issues.
Despite the creation of the Tu-95V bomb-carrier aircraft, the actual test of the Tsar Bomba was postponed for political reasons: namely, Khrushchev's visit to the United States and a pause in the Cold War. The Tu-95V during this period was flown to Uzyn, situated in today's Ukraine, and was used as a training aircraft; therefore, it was no longer listed as a combat aircraft. With the beginning of a new round of the Cold War in 1961, the test was resumed. The Tu-95V had all connectors in its automatic release mechanism replaced, the bomb bay doors removed and the aircraft itself covered with a special, reflective white paint.
In the fall of 1961, the aircraft was modified for testing AN602 at the Kuibyshev aircraft plant.
Khrushchev announced the upcoming tests of a 50-Mt bomb in his opening report at the 22nd Congress of the Communist Party of the Soviet Union on October 17, 1961. Before the official announcement, in a casual conversation, he told an American politician about the bomb, and this information was published on September 8, 1961, in The New York Times. The Tsar Bomba was tested on October 30, 1961.
The Tu-95V aircraft, No. 5800302, with the bomb took off from the Olenya airfield, and was flown to State Test Site No. 6 of the USSR Ministry of Defense located on Novaya Zemlya with the crew of nine:
The bomb, weighing 27 t (26.6 long tons; 29.8 short tons), was so large (8 m (26 ft) long by 2.1 m (6 ft 11 in) in diameter) that the Tu-95V had to have its bomb bay doors and fuselage fuel tanks removed. The bomb was attached to an 800-kilogram (1,800 lb), 1,600-square-metre (17,000 sq ft) parachute, which gave the release and observer planes time to fly about 45 km (28 mi) away from ground zero, giving them a 50 percent chance of survival. The bomb was released two hours after takeoff from a height of 10,500 m (34,449 ft) on a test target within Sukhoy Nos. The Tsar Bomba detonated at 11:32 (or 11:33) Moscow Time on October 30, 1961, over the Mityushikha Bay nuclear testing range (Sukhoy Nos Zone C), at a height of 4,200 m (13,780 ft) ASL (4,000 m (13,123 ft) above the target) (some sources suggest 3,900 m (12,795 ft) ASL and 3,700 m (12,139 ft) above target, or 4,500 m (14,764 ft)). By this time the Tu-95V had already escaped to 39 km (24 mi) away, and the Tu-16 53.5 km (33.2 mi) away. When detonation occurred, the shock wave caught up with the Tu-95V at a distance of 115 km (71 mi) and the Tu-16 at 205 km (127 mi). The Tu-95V dropped 1 kilometre (0.62 mi) in the air because of the shock wave but was able to recover and land safely. According to initial data, the Tsar Bomba had a nuclear yield of 58.6 Mt (245 PJ) (significantly exceeding what the design itself would suggest) and was overestimated at values all the way up to 75 Mt (310 PJ).
Although simplistic fireball calculations predicted it would be large enough to hit the ground, the bomb's own shock wave bounced back and prevented this. The 8-kilometre-wide (5.0 mi) fireball reached nearly as high as the altitude of the release plane and was visible at almost 1,000 km (620 mi) away. The mushroom cloud was about 67 km (42 mi) high (over seven times the height of Mount Everest), which meant that the cloud was above the stratosphere and well inside the mesosphere when it peaked. The cap of the mushroom cloud had a peak width of 95 km (59 mi) and its base was 40 km (25 mi) wide.
A Soviet cameraman said:
The clouds beneath the aircraft and in the distance were lit up by the powerful flash. The sea of light spread under the hatch and even clouds began to glow and became transparent. At that moment, our aircraft emerged from between two cloud layers and down below in the gap a huge bright orange ball was emerging. The ball was powerful and arrogant like Jupiter. Slowly and silently it crept upwards...Having broken through the thick layer of clouds it kept growing. It seemed to suck the whole Earth into it. The spectacle was fantastic, unreal, supernatural.”
The explosion of AN602, according to the classification of nuclear explosions, was an ultra-high-power low-air nuclear explosion. The results were impressive:
All buildings in the village of Severny, both wooden and brick, located 55 km (34 mi) from ground zero within the Sukhoy Nos test range, were destroyed. In districts hundreds of kilometres from ground zero, wooden houses were destroyed, stone ones lost their roofs, windows, and doors, and radio communications were interrupted for almost one hour. One participant in the test saw a bright flash through dark goggles and felt the effects of a thermal pulse even at a distance of 270 km (170 mi). The heat from the explosion could have caused third-degree burns 100 km (62 mi) away from ground zero. A shock wave was observed in the air at Dikson settlement 700 km (430 mi) away; windowpanes were partially broken for distances up to 900 kilometres (560 mi). Atmospheric focusing caused blast damage at even greater distances, breaking windows in Norway and Finland. Despite being detonated 4.2 km (3 mi) above ground, its seismic body wave magnitude was estimated at 5.0–5.25.
Immediately after the test, several US Senators condemned the Soviet Union. Prime Minister of Sweden, Tage Erlander saw the blast as the Soviets' answer to a personal appeal to halt nuclear testing that he had sent the Soviet leader in the week prior to the blast. The British Foreign Office, Prime Minister of Norway Einar Gerhardsen, Prime Minister of Denmark Viggo Kampmann and others also released statements condemning the blast. Soviet and Chinese radio stations mentioned the US underground nuclear test of a much smaller bomb (possibly the Mink test) carried out the day prior, without mentioning the Tsar Bomba test.
The creation and testing of a superbomb were of great political importance; the Soviet Union demonstrated its potential in creating a nuclear arsenal of great power (at that time, the most powerful thermonuclear charge tested by the United States was 15 Mt (Castle Bravo)). After the AN602 test the United States did not increase the power of its own thermonuclear tests and, in 1963 in Moscow, the Treaty Banning Nuclear Weapon Tests in the Atmosphere, Outer Space and Under Water was signed.
The scientific result of the test was the experimental verification of the principles of calculation and design of multistage thermonuclear charges. It was experimentally proven that there is no fundamental limitation on increasing the power of a thermonuclear charge, however, as early as October 30, 1949. Three years before the Ivy Mike test, in the Supplement to the official report of the General Advisory Committee of the US Atomic Energy Commission, nuclear physicists Enrico Fermi and Isidor Isaac Rabi noted that thermonuclear weapons have "unlimited destructive power" and that the cost of increasing the yield of the munition in 1950 financial year prices was 60 cents per kiloton of TNT. In the tested specimen of the bomb, to raise the explosion power by another 50 Mt, it was enough to replace the lead sheath with uranium-238, as was normally expected. The replacement of the cladding material and the decrease in the explosion power were motivated by the desire to reduce the amount of radioactive fallout to an acceptable level, and not by the desire to reduce the weight of the bomb, as is sometimes believed. The weight of the AN602 did decrease from this, but insignificantly. The uranium cladding was supposed to weigh about 2,800 kg (6,200 lb), the lead sheath of the same volume – based on the lower density of lead – is about 1,700 kg (3,700 lb). The resulting relief of just over one ton is weakly noticeable with a total mass of AN602 of at least 24 tons and did not affect the state of affairs with its transportation.
The explosion has become one of the cleanest in the history of atmospheric nuclear tests per unit of power. The first stage of the bomb was a uranium charge with a capacity of 1.5 Mt, which in itself provided a large amount of radioactive fallout; nevertheless, it can be assumed that AN602 was really relatively-clean – more than 97% of the explosion power was provided by a thermonuclear fusion reaction, which practically does not create radioactive contamination.
A distant consequence was the increased radioactivity accumulated in the glaciers of Novaya Zemlya. According to the 2015 expedition, due to nuclear tests, the glaciers of Novaya Zemlya are 65–130 times more radioactive than the background in neighboring areas, including contamination from the tests of the Kuz'kina Mother.
Sakharov was against nuclear proliferation, and played a key role in signing the 1963 Partial Test Ban Treaty. Sakharov became an advocate of civil liberties and reforms in the Soviet Union. These efforts earned him the Nobel Peace Prize in 1975.
The Tsar Bomba was the single most physically powerful device ever deployed on Earth. For comparison, the largest weapon ever produced by the US, the now-decommissioned B41, had a predicted maximum yield of 25 Mt (100 PJ). The largest nuclear device ever tested by the US (Castle Bravo) yielded 15 Mt (63 PJ) because of an unexpectedly-high involvement of lithium-7 in the fusion reaction; the preliminary prediction for the yield was from 4 to 6 Mt (17 to 25 PJ). The largest weapons deployed by the Soviet Union were also around 25 Mt (100 PJ) (e.g., the SS-18 Mod. 3 warhead).
The weight and size of the Tsar Bomba limited the range and speed of the specially-modified bomber carrying it. Delivery by an intercontinental ballistic missile would have required a much stronger missile (the Proton started its development as that delivery system). It has been estimated that detonating the original 100 Mt design would have released fallout amounting to about 26% of all fallout emitted since the invention of nuclear weapons. It was decided that a full 100 Mt detonation would create a nuclear fallout that was unacceptable in terms of pollution from a single test, as well as a near-certainty that the release plane and crew would be destroyed before it could escape the blast radius.
The Tsar Bomba was the culmination of a series of high-yield thermonuclear weapons designed by the Soviet Union and the United States during the 1950s (e.g., the Mark 17 and B41 nuclear bombs).
AN602 was never a practical weapon; it was a single product, the design of which allowed reaching a power of 100 Mt TE. The test of a 50-Mt bomb was, among other things, a test of the performance of the product design for 100 Mt. The bomb was intended exclusively for psychological pressure on the United States.
Experts began to develop military missiles for warheads (150 Mt and more) that have been redirected for space use:
There existed a common (but entirely false) myth that the Tsar Bomba was designed per personal order from Nikita Khrushchev, at a meeting on July 10, 1961, with a total research and development time of only 112 days; the actual development of the final stage of the Tsar Bomba (then already placed in KB-11) did indeed take 112 days. In fact, development began in 1956.[better source needed]
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Despite being exploded in the atmosphere, it generated substantial seismic signals. According to a bulletin of the U.S. Geological Survey it had seismic magnitude mb = 5.0 to 5.25 . ... from fireball radius scaling laws, one would expect the fireball to reach down and engulf the ground ... In fact, the shock wave reaches the ground ... and bounces upward, striking the bottom of the fireball, preventing actual contact with the ground.