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
B57 nuclear bomb B57 nuclear bomb The B57 nuclear bomb was a tactical nuclear weapon developed by the United States during the Cold War. Entering production in 1963 as the Mk 57, the bomb was designed to be dropped from high-speed tactical aircraft. It had a streamlined casing to withstand supersonic flight. It was 3 m (9 ft 10 in) long, with a diameter of about 37.5 cm (14.75 in). Basic weight was approximately 227 kilograms (500 lbs). Some versions of the B57 were equipped with a parachute retarder (a 3.8 m/12.5 ft diameter nylon/kevlar ribbon parachute) to slow the weapon's descent, allowing