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 15 nuclear bomb Mark 15 nuclear bomb The Mark 15 nuclear bomb, or Mk-15, was a 1950s American thermonuclear bomb, the first relatively lightweight (7,600 lb / 3450 kg) thermonuclear bomb created by the United States. A total of 1,200 Mark 15 bombs were produced from 1955 to 1957. There were three production variants: Mod 1, Mod 2, and Mod 3. The design was in service from 1955 to 1965. The Mark 15 is widely described as a transitional design between fission and thermonuclear weapons. The Mark 15 was a staged weapon (see Teller-Ulam design) that used radiation implosion from a fission nuclear