Nuclear fission Mexico, which was the scientific hub for research on bomb development and design. Other sites, notably the Berkeley Radiation Laboratory and the Metallurgical Laboratory at the University of Chicago, played important contributing roles. Overall scientific direction of the project was managed by the physicist J. Robert Oppenheimer. In July 1945, the first atomic explosive device, dubbed "Trinity", was detonated in the New Mexico desert. It was fueled by plutonium created at Hanford. In August 1945, two more atomic devices – "Little Boy", a uranium-235 bomb, and "Fat Man", a plutonium bomb – were used against the Japanese cities of Hiroshima
Mark 6 nuclear bomb US. Mark 18 bombs were eventually recycled into Mark 6 Mod 6 bombs after thermonuclear weapons were deployed in quantity. The Mark 18 was tested once in Operation Ivy King. Mark 6 nuclear bomb The Mark 6 nuclear bomb was an American nuclear bomb based on the earlier Mark 4 nuclear bomb and its predecessor, the Mark 3 Fat Man nuclear bomb design. The Mark 6 was in production from 1951 to 1955 and saw service until 1962. Seven variants and versions were produced, with a total production run of all models of 1100 bombs. The basic Mark 6 design