Manhattan Project Alamogordo: first atomic bomb test, 1945Jack Aeby/Los Alamos National LaboratoryU.S. government research project (1942–45) that produced the first atomic bombs.
American scientists, many of them refugees from fascist regimes in Europe, took steps in 1939 to organize a project to exploit the newly recognized fission process for military purposes. The first contact with the government was made by G.B. Pegram of Columbia University, who arranged a conference between Enrico Fermi and the Navy Department in March 1939. In the summer of 1939, Albert Einstein was persuaded by his fellow scientists to use his influence and present the military potential of an uncontrolled fission chain reaction to Pres. Franklin D. Roosevelt. In February 1940, , 000 was made available to start research under the supervision of a committee headed by L.J. Briggs, director of the National Bureau of Standards (later National Institute of Standards and Technology). On December 6, 1941, the project was put under the direction of the Office of Scientific Research and Development, headed by Vannevar Bush.
Groves, Leslie RichardLos Alamos National LaboratoryAfter the U.S. entry into World War II, the War Department was given joint responsibility for the project, because by mid-1942 it was obvious that a vast array of pilot plants, laboratories, and manufacturing facilities would have to be constructed by the U.S. Army Corps of Engineers so that the assembled scientists could carry out their mission. In June 1942 the Corps of Engineers’ Manhattan District was initially assigned management of the construction work (because much of the early research had been performed at , in Manhattan), and in September 1942 Brig. Gen. Leslie R. Groves was placed in charge of all Army activities (chiefly engineering activities) relating to the project. “Manhattan Project” became the code name for research work that would extend across the country.
It was known in 1940 that German scientists were working on a similar project and that the British were also exploring the problem. In the fall of 1941 Harold C. Urey and Pegram visited England to attempt to set up a cooperative effort, and by 1943 a combined policy committee with Great Britain and Canada was established. In that year a number of scientists of those countries moved to the United States to join the project there.
If the project were to achieve success quickly, several lines of research and development had to be carried on simultaneously before it was certain whether any might succeed. The explosive materials then had to be produced and be made suitable for use in an actual weapon.