Tsar Bomba (in Russian, Царь-бомба) is the Western nickname for the Soviet RDS-220 (РДС-220) hydrogen bomb (code name Vanya). Detonated by the Soviet Union on October 30, 1961, Tsar Bomba is the largest nuclear device ever detonated and the most powerful man-made explosion in history. With a yield of 50 megatons of TNT, Tsar Bomba was the culmination of a number of hydrogen bomb tests conducted throughout this time by both the Soviet Union and the United States.

Tsar Bomba was also referred to as “Kuzkina mat” (Кузькина мать) or “Kuzma's mother.” This nickname may refer to Nikita Khrushchev's promise made at a 1960 session of the United Nations General Assembly to show the United States a “Kuzkina mat,” which also roughly translates to “We'll show you!” There were many other nicknames associated with Tsar Bomba such as Big Ivan, Project 7000, and Product Code 202 (Izdeliye 202). The Central Intelligence Agency designated the Tsar Bomba nuclear test as “JOE 111.”

Design

A team of physicists led by Yuli Khariton designed Tsar Bomba. The team also included Andrei Sakharov, Viktor Adamsky, Yuri Babayev, Yuri Smirnov, and Yuri Trutnev.

The Tsar Bomba was a three-stage hydrogen bomb with a Trutnev-Babaev second and third stage design. A three-stage hydrogen bomb uses a fission-type atomic bomb as the first stage to compress the thermonuclear second stage. The energy produced from this explosion is then directed to compress the much larger thermonuclear third stage. There is evidence that Tsar Bomba utilized several third stages.

Tsar Bomba could have theoretically yielded as much as 100 megatons, but it would have resulted in a dangerous level of nuclear fallout (approximately 25% of all fallout produced since the invention of nuclear weapons in 1945). Additionally, the delivery plane would not have had sufficient time to retreat to a safe distance. Therefore, to minimize nuclear fallout, the third stage incorporated a lead tamper instead of a uranium-238 fusion tamper. It has been speculated that the second stage used this method as well.

The uranium-238 fusion tamper greatly amplifies the reaction by fissioning uranium atoms with fast neutrons from the fusion reaction. Because fast fissioning was eliminated, thermonuclear fusion accounted for as much as 97% of the yield. Thus, despite its huge yield, Tsar Bomba did not actually generate much nuclear fallout.

The Test

A Tu-95V Soviet long range bomber piloted by Major Andrei Durnovstev delivered Tsar Bomba during the test. The bomber was accompanied by a Tu-16 observer plane that was responsible for collecting air samples and filming the test. A reflective white paint was used on the planes to minimize thermal damage to their surfaces.

Tsar Bomba weighed 27 metric tons or 59,525 lbs. It was 26 feet in length and 6.9 feet in diameter. The bomb bay doors and fuselage fuel tanks were removed from the Tu-95V due to its large size. Tsar Bomba was attached to a parachute weighing nearly 1,800 lbs., which provided the bomber and observer planes additional time to fly approximately 30 miles away from ground zero prior to detonation. Despite the addition of reflective paint and the parachute, a 50/50 chance of survival was predicted for those on board.

On October 30, 1961, Tsar Bomba was detonated in the atmosphere at 11:32 Moscow Time over the Mityushikha Bay Nuclear Testing Range in the northern Arctic Circle. The bomb was set by barometric sensors to detonate at 13,000 feet and was dropped from a height of 34,000 feet.

The Tsar Bomba yield was approximately 1,570 times more powerful than the yield of the bombs dropped on Hiroshima and Nagasaki combined, and 10 times more powerful than all of the conventional weapons exploded during World War II. Tsar Bomba also represented 25% of the estimated yield of the Krakatoa volcanic eruption of 1883, and 10% of all nuclear tests by this point. By comparison, the B41, the largest United States nuclear weapon, had a theoretical yield of 25 megatons. The largest nuclear device ever detonated by the United States was Castle Bravo with a yield of 15 megatons. The largest nuclear weapon deployed by the Soviet Union, the SS-18 Mod. 3 ICBM warhead, was also approximately 25 megatons.

Aftermath

All of the wooden and brick buildings in nearby Severny, located 34 miles from the aiming point or ground zero, were annihilated. In other Soviet districts located over a hundred miles from ground zero, wooden houses were demolished, and brick and stone ones suffered damages. Radio communication outages were also reported. One test witness felt the thermal effects at a distance of 170 miles, even with dark goggles. The intense heat from the detonation was capable of causing third-degree burns at a distance of 62 miles from ground zero. The shock wave was felt as far away as the Dikson settlement located 430 miles away, and windows shattered at a distance of 560 miles. Windows even shattered as far away as Norway and Finland due to atmospheric focusing of the shock wave. Despite being an air burst detonated 13,000 feet above ground, Tsar Bomba’s seismic magnitude was estimated at 5–5.25. Seismic sensors continued to register shockwaves even after a third revolution around the Earth.

The original Atomic Energy Commission estimate of the Tsar Bomba yield was 55–60 megatons, but since the end of the Cold War and fall of the Soviet Union, all Russian sources have confirmed its yield as 50 megatons. Even though calculations suggested the explosion would reach the ground, this was prevented when the bomb’s extremely large shock wave was reflected. The fireball nearly reached the altitude of the release aircraft. At the point of detonation, the aircraft dropped approximately one half mile in altitude due to the shock wave, but would make it to safety. The Tsar Bomba mushroom cloud was approximately 40 miles high, seven times higher than Mount Everest. The cloud reached higher than the stratosphere at its highest altitude. The top of the cloud had a width of 59 miles and the base a width of 25 miles.

The extreme damage and devastation wrought by thermonuclear weapons like the Tsar Bomba is unimaginable. If such a weapon exploded in a large American city such as New York, Chicago, San Francisco, or Washington, D.C., their metropolitan areas plus large portions of their surrounding suburbs would be completely destroyed and nearly devoid of all life.

To see the destructive effects of nuclear weapons on various cities across the globe, please visit Alex Wellerstein's NUKEMAP.

Thanks to David Wargowski for his assistance with this article.