Test: No. 130
Time: 11:32 AM 30 October 1961 (Moscow Time)
Location: Mityushikha Bay test range, Novaya Zemlya Island (located above the arctic circle in the Arctic Sea)
Test Height and Type: Parachute retarded airburst, 4000 m altitude
Yield: 50 Megatons
The Russians have always loved building the biggest, despite the very scale of their accomplishments often rendering them useless.
The Tsar Kolokol is the world's largest bell, but has never rung a note. Still on display in the Moscow Kremlin it weighs 222 tons, is over 20 feet high and boasts a diameter of 21 and a half feet. A fire in 1737 cracked a huge slab of metal, weighing 11.5 tonnes, from the bell when it was still in its casting pit and that was that.
The world's largest cannon Tsar Pushka (Царь-пушка - "king of cannons") was founded in 1586 by Andrey Chokhov with the intention of defending the Kremlin. It weighs 86,668 pounds, is 17 feet 6 inches long and has a theoretical calibre of 35 inches. Vast as this howitzer is, the cannon balls, cast in 1835, displayed alongside it are still too big to fit down its maw. It was actually designed to fire grapeshot, and has never fired a shot in anger, though its ornamentation suggests it was always intended for display.
The ludicrous Tsar Tank was designed as a genuine weapon of war. Also known as the Netopyr (Нетопырь - Pipistrellus bat) or Lebedenko Tank it was a Russian answer to the ground breaking british tanks of the Great War. The vehicle received its nickname because its model, when carried by the back wheel, resembled a bat hanging asleep. Thankfully for the safety of the soliders it might have carried into battle, it was scrapped after tests proved it was utterly unwieldy and desperately vulnerable to artillery fire.
Eschewing the use of caterpillar tracks, the tank rather brilliantly chose an enormous tricycle design. The front spoked wheels were 27 feet in diameter; the back one was smaller, 5 feet high. The upper cannon turret was 26 feet off the ground, while the hull was nearly 40 feet across, with two more cannon in the sponsons. Quite how enemy fire was supposed to miss it remains a mystery.
The huge wheels were supposed to allow it to cross any obstacle on the battlefield, in reality its bulk of over 40 metric tons left the back wheel stuck in soft ground and ditches and the front wheels, powered by one 250 hp motor each, were insufficient to pull it out. This led to a fiasco of tests before the high commission in August 1915, it was cancelled in 1916 and the last of the two examples built was dismateled for scrap in 1923.
The Tsar bomb shows the Soviets hadn't abandoned every tradition of the Tsarist age, although its western (and now russian) nickname would never have been used by the Soviet authorities of the time. During its development it was, of course, called Ivan while Sakharov calls it simply 'Big Bomb' in his Memoirs.
It was simply the largest nuclear weapon ever constructed or detonated. This 8 metre, three stage weapon, weighing about 27 tons, was designed to yield 100 megatons, that is an explosion equivilent to 100 million metric tons of TNT. No Soviet test prior to the 1961 resumption had yielded more than 3 megatons. Tsar Bomba was limited to 50 megatons for its test, with the uranium fusion stage replaced by lead in the tertiary, and possibly secondary, stage. This eliminated 97% of its fall out. At full yield it would have increased the world's total fission fallout since the invention of the atomic bomb by 25%.
It was developed in an incredibly short time. On July 10, 1961 Nikita Khrushchev told Andrei Sakharov, the senior weapon designer who would become the USSR's most famous dissident, to develop a 100 megaton bomb by September to create the maximum political impact. It was designed to intimidate the west, rather than for any practical use in warfare. The Berlin Wall was about to be built in August, short range missiles were to be deployed to Cuba, prompting the missile crisis and the Soviets wanted to forstall any intervention by the west. 'Ivan' was tested only 16 weeks after its inception.
Sakharov recounts that the mathematical analysis normally conducted for a new thermonuclear design was skipped, with estimates and approximations substitued at every turn and design and construction occuring simultaneously. It was built at Arzamas-16, now called Sarov, one of ten 'secret' Soviet cities dedicated to the production of nuclear weapons. These cities were closed to all foriegners and most Russians themselves did not know of their existence or true purpose. Over 20 cities and military areas remain closed to foriegners and most Russian citizens even today.
A de facto nuclear test moratorium had existed between the US, USSR and UK since the conclusion of the last US and Soviet test series in 1958, and two years of discussion had been conducted regarding formal limitations on nuclear testing. But the Cold War continued at high pitch, and the Khrushchev decided to resume its programme with a "testing spectacular" to 'show the imperialists what we could do' coincide with the Twenty Second Congress of the Communist Party.
Khrushchev announced the new superbomb on the day the Soviet tests resumed on 1st September 1961, putting pressure on the scientists to produce a workable bomb. Alluding to this, Sakharov said: "If we don't make this thing, we'll be sent to railroad construction." [Adamsky and Smirnov 1998]. This was however a marked improvement over the days of Stalin when nuclear weapon designers ruminated over the prospect of being shot!
Far too large for any ICBM it was dropped from a specially modified Tu-95 "Bear A" strategic bomber piloted by mission commander Major Andrei E. Durnovtsev. Weighing 2 and half times the planes normal bomb load it was carried externally, too large for the bomb bay.
The Tu-95 and an accompanying TU-16 'airbourne laboratory' were covered with a special white reflective paint to protect them from the thermal radiation of the fireball - the 50 Mt test was capable of inflicting third degree burns 100 km away. At full capacity the bomb would have burnt everyone within a radius of 170 km - only slightly less than the width of West Germany. Turning immediately, and powering away at maximum speed, the bomber had at most a minute to get clear.
Even its retarding 800 kg parachute was on a vast scale, its fabrication disrupting the less than developed Soviet nylon hosiery industry. Even special ground handling equipment had had to be developed to lift the bomb to the aircraft. Built on a raiway flatcar, it was delivered by rail and loaded directly onto the bomber.
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 metres, and designed to detonate at a height of 4,000 m over the land surface (4,200 m over sea level) by barometric sensors.
Since 50 Mt is 2.1×1017 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 5.3×1024 watts or 5.3 yottawatts. This is equivalent to approximately 1% of the energy output of the Sun during the same fraction of a second. 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.
Despite exploding at 4,000 m (13,000 ft) the vast fireball engulfed the ground below it, and swelled upward to nearly the height of the release plane. The blast pressure below the burst point was 300 PSI, six times the peak pressure at Hiroshima. Despite overcast skies, the flash was seen 1,000 kilometers away. One observer recalls feeling the heat flash 270 km away.
One cameraman recalled: "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."
Another observer, farther away, described what he witnessed as: "... a powerful white flash over the horizon and after a long period of time he heard a remote, indistinct and heavy blow, as if the earth has been killed!"
In districts hundreds of kilometers from ground zero, wooden houses were destroyed, and stone ones lost their roofs, windows and doors; and radio communications were interrupted for almost one hour. A gigantic mushroom cloud rose as high as 64 kilometers (210,000 ft). The seismic shock was measurable even on its third passage around the world.
Some time after the explosion, photographs were taken of ground zero. "The ground surface of the island has been levelled, swept and licked so that it looks like a skating rink," a witness reported. "The same goes for rocks. The snow has melted and their sides and edges are shiny. There is not a trace of unevenness in the ground.... Everything in this area has been swept clean, scoured, melted and blown away."
[Adamsky and Smirnov 1998]
The radius of complete destruction extended to 25 km, and ordinary houses would have been severely damaged out to 35 km. Atmospheric focusing would have generated localised regions of destructive blast pressure over 1000 km away. Had it been used in western Europe the fall out would have blown into the Soviet Union, while the chances of the slow, prop driven Tu-95 evading American fighters for 8 hours to drop the bomb on New York, Chicago or L.A. were remote.
Although Tsar Bomba was never deployed as a weapon, it exemplified Soviet strategic thinking in its day. Hydrogen bombs were still too clumbersome to be carried by ICBMs at the time and the Soviets believed that few of their bombers would penetrate US defences, and so wished to maximise the destruction wreaked by every one. Prior to satellite intelligence, each side lacked precise knowledge of the location of the other side's military and industrial facilities and a bomb dropped without benefit of Global positioning systems could easily miss its intended target by 5 km or more. Parachute retardation would only worsen this inaccuracy.
The Soviet philosophy was to ensure a bomb would wipe out an entire large city even if dropped 5-10 km from its center. This objective meant that yield and effectiveness were linked up to a point. The advent of ICBMs accurate to 500 m and especially of GPS made such a design philosphy 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.
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. On 16 January 1963 Khrushchev made an explicit claim that the Soviet Union was in possession of a 100 megaton bomb, claiming that it was located in East Germany.
'We will bury you.'
Sources - Wikipedia, Atomic Central, Nuclear Weapon Archive, Andrei Sakharov.