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
Mark 8 nuclear bomb bomb, was developed as a lightweight airburst (surface target) bomb. The Mark 10 project was cancelled prior to introduction into service, replaced by the much more fissile-material-efficient Mark 12 nuclear bomb implosion design. Mark 8 nuclear bomb The Mark 8 nuclear bomb was a nuclear bomb, designed in the late 1940s and early 1950s, which was in service from 1952 to 1957. The Mark 8 was a gun-type nuclear bomb, which rapidly assembles several critical masses of fissile nuclear material by firing a fissile projectile or "bullet" into a hollow opening in a larger fissile "target", using a system which