Tsar

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. The Boeing KC-135A-BN 55-3121 was said to be the fourth KC-135 built. 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 a uranium-238 fusion tamper but, because only one bomb was built to completion, that capability has never been demonstrated. The bomb is listed in the Guinness Book of Records as the most powerful thermonuclear device that has passed the test. 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.