The Manhattan Project
The American atomic program takes shape
While engaged in one war in Europe and another in the Pacific, the United States would launch the largest scientific effort undertaken to that time. It would involve37 installations throughout the country, more than a dozen university laboratories, and 100,000 people, including the Nobel Prize-winning physicists Arthur Holly Compton, Enrico Fermi, Richard Feynman, Ernest Lawrence, and Harold Urey.
The first contact between the scientific community and the U.S. government regarding atomic research was made by George B. Pegram of Columbia University. Pegram arranged a conference between Fermi and officers of the U.S. Navy in March 1939. In July Leo Szilard and Eugene Wigner conferred with Einstein, and the three later went to New York to meet with National Recovery Administration economist Alexander Sachs. Supported by a letter from Einstein, Sachs approached Pres. Franklin D. Roosevelt and explained the significance of nuclear fission to him. Roosevelt formed the Advisory Committee on Uranium, appointing Lyman Briggs, director of the National Bureau of Standards, to serve as its chair. In February 1940 a fund of $6,000 was made available to begin research; by the time of its completion, the project’s budget would exceed $2 billion.
U.S. officials were now well aware of Adolf Hitler’s atomic ambitions. In his letter to Roosevelt, Einstein explicitly called attention to uranium reserves in Czechoslovakia that had fallen under the control of the Third Reich in March 1939. The British had also begun studying fission, and Urey and Pegram visited the United Kingdom to see what was being done there. By August 1943 a combined policy committee had been established with the United Kingdom and Canada. Later that year a number of scientists of those countries moved to the United States to join the project that by then was well underway.
On December 6, 1941, one day before the Japanese attack on Pearl Harbor, the project was placed under the direction of Vannevar Bush and the Office of Scientific Research and Development (OSRD). Bush’s staff included Harvard University Pres. James B. Conant, Pegram, Urey, and Lawrence, among others. Alongside this scientific body was created the “Top Policy Group,” consisting of Bush, Conant, Roosevelt, U.S. Vice Pres. Henry Wallace, U.S. Secretary of War Henry Stimson, and U.S. Army Chief of Staff George C. Marshall.
Because there was no way of knowing in advance what technique would succeed in creating a functional bomb, it was decided to work simultaneously on several methods of isolating uranium-235 while also researching reactor development. The goal was twofold: to learn more about the chain reaction for bomb design and to develop a method of producing a new element, plutonium, which was expected to be fissile and could be isolated from uranium chemically. Lawrence and his team developed an electromagnetic separation process at the University of California, Berkeley, while Urey’s group at Columbia University experimented with the conversion of uranium into a gaseous compound that was then permitted to diffuse through porous barriers. Both of these processes, particularly the diffusion method, required large complex facilities and huge amounts of electric power to produce even small amounts of separated uranium-235. It soon became clear that an enormous physical infrastructure would have to be built to support the project.
On June 18, 1942, the War Department assigned management of construction work related to the project to the U.S. Army Corps of Engineers’ Manhattan District (much early atomic research—most notably Urey’s group—was based at Manhattan’s Columbia University). On September 17, 1942, Brig. Gen. Leslie R. Groves was placed in charge of all Army activities relating to the project. “Manhattan Project” became the code name applied to this body of atomic research that would extend across the country.
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