In the years before the formal establishment of the Manhattan Project, physicists across the United States conducted research on the atom in response to growing interest and discoveries of its secrets. As early as 1939, the U.S. government began to organize and fund nuclear research.
The Einstein-Szilard Letter
The origins of U.S. government involvement in atomic research began in 1939 with the announcement that German scientists Otto Hahn and Fritz Strassmann had discovered fission. This discovery prompted fears, particularly in physicist Leo Szilard, that Germany might develop an atomic bomb. Szilard soon contacted Alexander Sachs, an economist and a close friend of President Franklin Delano Roosevelt, who advised that they write a letter to the president warning him of this imminent danger. Sachs also suggested that they involve Albert Einstein, so as to give the letter more credence.
Although the letter was finished by August of 1939, Sachs would not bring it to President Roosevelt until October due to the outbreak of World War II. As Sachs explained, he wanted to bring it to Roosevelt in person so that it “would come in by way of the ear and not as a sort of mascara on the eye.” After reading the letter, Roosevelt replied, “Alex, what you are after is to see the Nazis don’t blow us up.” Roosevelt then called in his aide, General Edwin “Pa” Watson: “Pa! This requires action!” (Hewlett and Anderson 17).
The Uranium Committee
In 1939, there was not yet an efficient liaison between the U.S. government and the scientific community. To alleviate this problem, Roosevelt established the Advisory Committee on Uranium to determine the feasibility of a nuclear chain reaction. The Committee, chaired by Lyman Briggs, was made up of both civilian and military members and was instructed to coordinate with Sachs as a representative of Roosevelt.
The Uranium Committee issued its first report on November 1, 1939, recommending that the United States acquire a supply of uranium oxide for continued research and development. It later recommended that the government also fund research into methods of isotope separation as well as Szilard’s and Enrico Fermi’s ongoing research on nuclear chain reactions at Columbia University.
In June 1940, President Roosevelt took another step in organizing atomic research when he created the National Defense Research Committee (NDRC). The new head of the NDRC, Vannevar Bush, anticipated that the United States would soon be drawn into World War II and wanted an effective means to mobilize science for the war effort. As an independent organization, the NDRC would be able to make decisions and request funding without the approval of the Army or the Navy. The Uranium Committee would also be able to be independent from the military, and it was reorganized to have no military membership. The NDRC also gave a stronger scientific voice in the executive branch.
Nevertheless, as research progressed, there were clear limitations on the scope of research given the resources available. Ernest Lawrence, for example, became frustrated with the slow pace of the project, as he had recently discovered elements 93 and 94 (neptunium and plutonium), offering another possible path to the bomb. Fermi also wanted more funding to build an experimental pile, which could prove the possibility of a nuclear chain reaction. The NDRC and Bush, however, were concerned that the nuclear project would ultimately produce only power, not a weapon, and thus took a measured approach so as to see what would be most useful to the war effort.
The MAUD Committee Report
The U.S. government began to have more confidence in the prospects of the bomb project after the NDRC received scientific results from the United Kingdom suggesting that a bomb was in fact possible. In 1940, Prime Minister Winston Churchill created an advisory group on uranium, the MAUD Committee, in response to the Frisch-Peierls Memorandum, which recommended the development of an atomic bomb. In March 1941, the MAUD Committee issued a report which categorically stated “that the scheme for a uranium bomb is practicable and likely to lead to decisive results in the war… that this work [should] be continued on the highest priority and on the increasing scale necessary to obtain the weapon in the shortest possible time” and “that the present collaboration with America should be continued and extended especially in the region of experimental work.”
The MAUD Committee Report was soon sent to the United States for evaluation. With no reply for several weeks, however, Australian scientist Mark Oliphant flew to Washington to scope out the situation. Oliphant met with Lyman Briggs and was disappointed to find that “this inarticulate and unimpressive man had put the reports in his safe and had not shown them to members of his committee” (Rhodes 372). Frustrated, Oliphant visited Ernest Lawrence to explain the urgency of the situation, and with his help, Oliphant’s message eventually made its way to Vannevar Bush.
The S-1 Committee
By the time Bush received the MAUD Committee Report, the administrative structure of U.S. uranium research had drastically changed. On June 28, 1941, just days after the German army invaded the Soviet Union, President Roosevelt established the Office of Scientific Research and Development (OSRD), with Bush at its head. The NDRC, now led by James Conant, was reorganized as an advisory body to the OSRD. The Uranium Committee became the OSRD Section on Uranium, or the S-1 Committee.
The MAUD Committee Report was the proof that Bush and Conant had been waiting for, and they quickly moved to verify its results. With the help of a committee from the National Academy of Sciences led by Arthur Compton and including Enrico Fermi, Leo Szilard, and Eugene Wigner, they were able to confirm by early December that a bomb could theoretically be built for wartime use. After the attack at Pearl Harbor on December 7, large scale work on the bomb project was a foregone conclusion.
The S-1 Committee formally held its first meeting on December 18, 1941, signaling an official shift from the research phase of the project. As Conant noted, “the atmosphere was charged with excitement – the country had been at war nine days, an expansion of the S-1 program was now an accomplished matter. Enthusiasm and optimism reigned” (Rhodes 398). The meeting also marked the beginning of wartime secrecy for the project, as the committee established a basic code for its notes: plutonium was “copper”, U-235 “magnesium,” and uranium “tube alloy” (a reference to the code name for the British Atomic Bomb Project).
Nevertheless, as the project progressed from research to development, Bush and Conant realized that the S-1 Committee did not have the resources for full-scale construction. They eventually opted to turn to the Army for support, leading to the establishment of the Manhattan Engineer District under the command of General Leslie Groves.