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Tsar Bomba

2007 Schools Wikipedia Selection. Related subjects: Military History and War

   Site of the detonation.
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   Site of the detonation.

   Tsar Bomba (Russian: Царь-бомба, literally " Tsar-bomb") is the Western
   name for the largest, most powerful nuclear weapon ever detonated.
   Developed by the Soviet Union, the bomb of about 50 megatons was
   codenamed Ivan by its developers.

   The bomb was tested on October 30, 1961 in Novaya Zemlya, an island in
   the Arctic Sea. The device was scaled down from its original design of
   100 megatons to reduce the resulting nuclear fallout.

Origins

   Soviet Premier Nikita Khrushchev initiated the project on July 10,
   1961, requesting that the test take place in late October, while the
   22nd Congress of the CPSU was in session. This fifteen-week deadline
   could be met because the needed nuclear components were all
   off-the-shelf.

   The term "Tsar Bomba" harkens to the historical Russian practice of
   building impractically large things as shows of power or prowess, e.g.,
   a massive bell ( Tsar Kolokol), the world's largest cannon ( Tsar
   Pushka), and the unwieldy Tsar Tank. Although the bomb was so named by
   Western sources (the strictly anti-monarchist Soviet Union would not
   have named this symbol of national pride in honour of its past rulers),
   the name is now widely used in Russia.

   Codenamed "Ivan" during its development, the Tsar Bomba was not
   intended for use in warfare, but should be seen as an instance of the
   Cold War-era sabre-rattling indulged in by the USSR and the USA.
   Khrushchev gave the go-ahead at a time of grave tension: the first
   Berlin wall was erected in August 1961. Moreover, the USSR had recently
   ended a de facto moratorium on nuclear tests (which lasted for nearly
   three years), and was about to deploy nuclear weapons in Cuba, which
   led to the Cuban Missile Crisis.

   In a speech to the United Nations General Assembly about the test,
   Khrushchev used the Russian idiom "show somebody Kuzka's mother", which
   means "to punish". Because of this, sometimes the weapon is referred to
   as "Kuzka's mother" (Кузькина мать) in Russian sources.

Design

   The Tsar Bomba was a multi-stage hydrogen bomb with a yield of about 50
   megatons (Mt). The initial three-stage (fission- fusion-fission) design
   was capable of approximately 100 Mt, but at a cost of too much
   radioactive fallout. To limit fallout, the third stage, consisting of a
   uranium-238 fission tamper (which greatly amplifies the reaction by
   fissioning uranium atoms with fast neutrons from the fusion reaction),
   was replaced with one made of lead. This eliminated fast fission by the
   fusion-stage neutrons, so that approximately 97% of the total energy
   resulted from the fusion stage 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
   feature regression, as most of the fallout from a test of the bomb
   would fall on populated Soviet territory.

   The components were designed by a team of physicists, headed by
   Academician Julii Borisovich Khariton, which included Andrei Sakharov,
   Victor Adamsky, Yuri Babayev, Yuri Smirnov, and Yuri Trutnev. Shortly
   after the Tsar Bomba was detonated, Sakharov began speaking out against
   nuclear weapons, which culminated in him becoming a full-blown
   dissident (see his Memoirs).

Test

   The Tsar Bomba was flown to its test site by a specially modified Tu-95
   release plane which took off from an airfield in the Kola peninsula,
   flown by Major Andrei E. Durnotsev. The release plane was accompanied
   by a Tu-16 observer plane which took air samples and filmed the test,
   hence the movie stills that illustrate this and other articles about
   the test. Both aircraft were painted with a special reflective white
   paint to limit heat damage.

   The bomb, weighing 27 tonnes, was so large (8 meters long by 2 m in
   diameter) that the Tu-95 had to have its bomb bay doors and wing fuel
   tanks removed. The bomb was attached to an 800 kg fall retardation
   parachute, which gave the release and observer planes time to fly about
   45 km from ground zero. Failing such retardation, the bomb would have
   either reached its planned detonation altitude so fast it would have
   turned the test into a suicide mission, or crashed into the ground at
   high speed, with unpredictable results. The USA has fitted a few of its
   nuclear bombs with parachute retardation for the same reason. An
   apocryphal story has it that the fabrication of this parachute required
   so much raw nylon that the small Soviet nylon hosiery industry was
   noticeably disrupted.

   The Tsar Bomba detonated at 11:32 a.m., located approximately at
   73.85° N 54.50° E , over the Mityushikha Bay nuclear testing range
   (Sukhoy Nos Zone C), north of the Arctic Circle on Novaya Zemlya Island
   in the Arctic Sea. The bomb was dropped from an altitude of 10,500 m,
   and designed to detonate at a height of 4,000 m over the land surface
   (4,200 m over sea level) by barometric sensors.

   The original USA estimate of the yield was 57 Mt, but since 1991 all
   Russian sources have stated its yield as "only" 50 Mt. Nonetheless,
   Khrushchev warned in a filmed speech to the Communist parliament of the
   existence of a 100 Mt bomb (technically the design was capable of this
   yield). The fireball touched the ground, reached nearly as high as the
   altitude of the release plane, and was seen 1,000 km away. The heat
   could have caused third degree burns at a distance of 100 km. The
   subsequent mushroom cloud was about 60 km high and 30–40 km wide. The
   explosion could be seen and felt in Finland, even breaking windows
   there. Atmospheric focusing caused blast damage up to 1,000 km away.
   The seismic shock created by the detonation was measurable even on its
   third passage around the earth.

   Since 50 Mt is 2.1×10^17 joules, the average power produced during the
   entire fission-fusion process, lasting around 3.9×10^-8 seconds or 39
   nanoseconds, was a power of about 5.3×10^24 watts or 5.3 yottawatts.
   This is equivalent to approximately 1% of the power output of the Sun.
   The detonation of Tsar Bomba therefore qualifies, even to this day, as
   being the single most powerful device ever utilized throughout the
   history of humanity. By contrast, the largest weapon ever produced by
   the United States, the now-decommissioned B41, had a predicted maximum
   yield of 25 Mt, and the largest nuclear device ever tested by the USA (
   Castle Bravo) yielded 15 Mt. Note the recent comparison with asteroid
   impacts which may have formed the Chicxulub Crater and the Wilkes Land
   crater, both larger events by some six orders of magnitude.

Analysis

   The weight and size of the Tsar Bomba limited the range and speed of
   the specially modified bomber carrying it, and ruled out its delivery
   by an ICBM (although on, December 24, 1962, a 50MT ICBM warhead
   developed by Chelyabinsk-70 was detonated at 24.2 megatons to reduce
   fallout ). Much of its high yield was—in terms of organic
   destruction—inefficiently radiated upwards into space. It has been
   estimated that detonating the original 100 Mt design would have
   released fallout amounting to about 25% of all fallout emitted since
   the invention of nuclear weapons. Hence the Tsar Bomba was an
   impractically powerful weapon. The Soviets decided that such a test
   blast would create too great a risk of nuclear fallout, and a near
   certainty that the release plane would be unable to reach safety before
   detonation.

   The Tsar Bomba was the culmination of a series of very high-yield
   thermonuclear weapons designed by the USSR and USA (e.g., the Mark-17
   and B41) during the 1950s. Such bombs were designed because:
     * The nuclear bombs of the day were large and heavy, regardless of
       yield, and could only be delivered by strategic bombers. Hence
       yield was subject to dramatic economies of scale;
     * It was feared that many, if not most, bombers would fail to reach
       their targets, because their size and low speed made detection and
       interception easy. Hence maximizing the firepower carried by any
       single bomber was vital;
     * Prior to satellite intelligence, each side lacked precise knowledge
       of the location of the other side's military and industrial
       facilities;
     * A bomb dropped without benefit of satellite navigation systems
       could easily miss its intended target by 5 km or more. Parachute
       retardation would only worsen this inaccuracy.

   Thus certain bombs were designed to wipe out an entire large city even
   if dropped 5–10 km from its centre. This objective meant that yield and
   effectiveness were positively correlated, at least up to a point.
   However, the advent of ICBMs accurate to 500 m or better, and
   especially the advent of satellite navigation, made such a design
   philosophy obsolete. Subsequent nuclear weapon design, in the 1960s and
   1970s, focused primarily on increased accuracy, miniaturization, and
   safety. The standard practice for a number of years has been to employ
   multiple smaller warheads (e.g., MIRVs) to " carpet" an area. This is
   believed to result in greater ground damage.
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