Despite its immense power, the Castle Bravo test is only the fifth largest test in history. The crater left behind has a diameter of 6,510 feet and a depth of 250 feet. The mushroom cloud formed after the detonation grew to nearly four-and-a-half miles wide and reached a height of 130,000 feet six minutes after the detonation. The Castle Bravo device weighed approximately 23,500 pounds. The miscalculation occurred because scientists did not realize that the “dry” source of fusion fuel, lithium deuteride with 40 percent content of lithium-6 isotope, would contribute so greatly to the overall yield of the detonation. nuclear weapons used on Hiroshima and Nagasaki in 1945. Scientists were shocked when Castle Bravo produced an astounding 15 megaton yield, making it 1,000 times as powerful as the U.S. They predicted that the yield of the device would be roughly five to six megatons (a megaton is the equivalent of one million tons of TNT). The designers of Castle Bravo seriously miscalculated the yield of the device, resulting in critical radiation contamination. Castle Bravo was the first deliverable thermonuclear device, and the test aimed to pave the way for the creation of more effective weapons, including weapons that could be deliverable by aircraft. Whereas Ivy Mike was a “wet” thermonuclear device (meaning that the hydrogen isotope used in the device was liquid), Castle Bravo was a “dry” device, which greatly reduced its weight and size. scientists rushed to create a set of deliverable thermonuclear designs. The United States tested its first thermonuclear device, known as Ivy Mike, two years earlier in 1952, also in the Marshall Islands. While the test advanced thermonuclear weapons design, miscalculations about the yield resulted in the largest U.S.

military beginning in 1946 for nuclear weapons testing research. The operation took place at Bikini Atoll, part of the Marshall Islands, used by the U.S. Atomic Energy Commission and Department of Defense. The test was part of a larger operation for testing high-yield nuclear devices, known as Operation Castle, conducted by the U.S.

March 1 marks the 60th anniversary of Castle Bravo, the largest thermonuclear device ever detonated by the United States.

Tsar bomba crater