Nuclear fission the Manhattan Project during World War II (September 1, 1939 – September 2, 1945) carried out most of the early scientific work on fission chain reactions, culminating in the three events involving fission bombs that occurred during the war. The first fission bomb, codenamed "The Gadget", was detonated during the Trinity Test in the desert of New Mexico on July 16, 1945. Two other fission bombs, codenamed "Little Boy" and "Fat Man", were used in combat against the Japanese cities of Hiroshima and Nagasaki in on August 6 and 9, 1945 respectively. Even the first fission bombs were thousands of
B83 nuclear bomb maneuvering space vehicles to "knock" an asteroid off course, should it pose a risk to the Earth. B83 nuclear bomb The B83 thermonuclear weapon is a variable-yield unguided bomb developed by the United States in the late 1970s, entering service in 1983. With a maximum yield of , it is the most powerful nuclear free-fall weapon in the United States arsenal. It was designed at Lawrence Livermore National Laboratory, and the first underground test detonation of the production B83 took place on 15 December 1984 in Nevada at Area U19ac. The B83 was based partly on the earlier B77 program,