History of the United States 6–3 decision in Korematsu v. United States Supreme Court case. Research and development took flight as well, best seen in the Manhattan Project, a secret effort to harness nuclear fission to produce highly destructive atomic bombs. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U.S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs. The first nuclear device ever detonated was an implosion-type bomb at the Trinity test, conducted at New Mexico's Alamogordo Bombing and Gunnery Range on
Mark 13 nuclear bomb Mark 13 nuclear bomb The Mark 13 nuclear bomb and its variant, the W-13 nuclear warhead, were experimental nuclear weapons developed by the United States from 1951 to 1954. The Mark 13 design was based on the earlier Mark 6 nuclear bomb design, which was in turn based on the Mark 4 nuclear bomb and the Mark 3 nuclear bomb used at the end of World War II. The Mark 13 bomb was nearly the same size as the Mark 6 nuclear bomb it was developed from; 61 inches in diameter and 128 inches long (150 cm by 320 cm),