Robert Julius Oppenheimer

Copyright Houghton Mifflin Company. All Rights Reserved.

America's development of the atomic bomb was called the Manhattan Project because it was administered after 1942 by a section of the army code-named the Manhattan District. Pressure for the project began in 1939, when two scientists in Berlin accomplished atomic fission in uranium. Believing that Germany might successfully develop an atomic bomb, Albert Einstein and other physicists persuaded President Franklin D. Roosevelt to establish a small research program.

In June 1941 the Office of Scientific Research and Development (osrd), headed by Vannevar Bush, was created to coordinate all government-sponsored scientific efforts, including the work on atomic fission. Under osrd the fission project expanded, involving teams at a number of universities, including Columbia, Princeton, California, and Chicago. By the spring of 1942, these teams had confirmed that atomic fission was possible through a chain reaction in uranium, and Dr. Ernest Lawrence in California had shown that rather than their requiring the very scarce uranium isotope U-235, they could convert a more common one, U-238, into a new fissionable element, plutonium.

In June 1942, Bush and his colleagues reported to the president that creating an atomic bomb appeared to be feasible, and that although the project would be extraordinarily demanding—scientifically, logistically, and financially —it could be accomplished in time to affect the course of the war. Roosevelt gave his approval to proceed, and the Manhattan District was established within the Army Corps of Engineers to coordinate resource mobilization and production.

Dr. Arthur Compton's team in Chicago produced the first chain reaction in uranium in December 1942. Thereafter, actually building the bomb became the primary focus. In 1943, after a new laboratory for the purpose was established in Los Alamos, New Mexico, under the direction of J. Robert Oppenheimer, the Army assumed full control of the project. Over the next two years, researchers worked furiously to solve a myriad of scientific problems. Gen. Leslie R. Groves supervised the vast project, keeping its intricate phases synchronized, establishing huge plants in Oak Ridge, Tennessee, and Hanford, Washington, to produce the needed materials, setting and enforcing production schedules, and maintaining security. In all, development of the bomb involved the labors of 125,000 people and cost nearly $2 billion.

The first test explosion took place July 16, 1945, at Alamogordo, New Mexico; its stunning success filled those present with both jubilation and awe. By order of the new president, Harry S. Truman, the first atomic bomb was dropped on Hiroshima, Japan, on August 6, 1945, followed by a second on Nagasaki three days later. The Japanese surrender followed on August 14. The successful conclusion of the Manhattan Project marked the beginning of the nuclear age.