The Manhattan Project: Making the Atomic Bomb

Enter the Army

The decision to proceed with production planning led directly to the involvement of the Army, specifically the Corps of Engineers. Roosevelt had approved Army involvement on October 9, 1941, and Bush had arranged for Army participation at S-1 meetings beginning in March 1942. The need for security suggested placing the S-1 program within one of the armed forces, and the construction expertise of the Corps of Engineers made it the logical choice to build the production facilities envisioned in the Conant report of May 23.

By orchestrating some delicate negotiations between the Office of Scientific Research and Development and the Army, Bush was able to transfer the responsibility for process development, materials procurement, engineering design, and site selection to the Corps of Engineers and to earmark approximately sixty percent of the proposed 1943 budget, or $54 million, for these functions. An Army officer would be in overall command of the entire project. This new arrangement left S-1, with a budget of approximately $30 million, in charge of only university research and pilot plant studies. Additional reorganization created an S-1 Executive Committee, composed of Conant, Briggs, Compton, Lawrence, Murphree, and Urey. This group would oversee all Office of Scientific Research and Development work and keep abreast of technical developments that might influence engineering considerations or plant design.²³ With this reorganization in place, the nature of the American atomic, bomb effort changed from one dominated by research scientists to one in which scientists played a supporting role in the construction enterprise run by the United States Army Corps of Engineers.

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