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
393d Bomb Squadron atomic bomb delivery techniques. The squadron carried out two Atomic Bombing missions over Japan in August 1945, being the only squadron in the world to ever carry out and deliver nuclear weapons in combat. Dropped the first atomic bomb on Hiroshima, Japan, on 6 August 1945, and the second atomic bomb on Nagasaki, Japan, on 9 August 1945. Reassigned to the United States in November 1945, becoming part of Continental Air Forces (later Strategic Air Command). Deployed to Kwajalein in 1946 to carry out Operation Crossroads atomic bomb tests on Bikini Atoll in July. Began upgrading to the new Boeing