Led by Brigadier General Leslie R. Groves, the United States Army Corps of Engineers directed the top-secret effort to build the world's first atomic bomb. To fulfill this mission, the Army Corps of Engineers created the Special Engineering Detachment (SED), which supplied critical technical support for the senior scientists and engineers at Los Alamos, Oak Ridge and Tinian Island. In addition, the Wendover Airfield in Utah and Tinian Island before delivering the bombs over Japan.
The Special Engineer Detachment
As the Manhattan Project grew in size and complexity, there was an increasing demand for workers with technical training and a scientific education. In 1943, the Commanding General of the Army Services Forces attempted to fill this void by authorizing the creation of a Special Engineer Detachment, allowing qualified enlisted men to work on the Project rather than be sent into combat. Within a few months, the SED was aggressively recruiting from college campuses, the Army Specialized Training Program (ASTP), and the National Scientific Roster. By 1945, the SED ballooned to include over 3, 000 soldiers scattered across the many Manhattan Project sties, with 1, 800 serving at Los Alamos alone. They worked on everything from bomb design to inventory control, often in tandem with their civilian counterparts.
While the members of the SED worked side-by-side with the civilians, they were still subject to Army discipline, training, pay, and housing conditions. Their barracks were notoriously poor and the soldiers were forced to undergo drills and physical training early in the morning, prior to their work in the laboratories. Although the SED were not civilians, they did not fit in the profile of typical GIs either. As SED veteran Robert Holmberg recalls, “Even though I was in the Army, I never considered myself Army. They wanted us to become a marching group. This was not what we liked to do, and we goofed off a lot.” The unit were far from the best marchers or most disciplined soldiers, but their contributions as mechanics, electricians, and engineers was invaluable.
The 509th Composite Group
As the creation of an atomic bomb came closer to fruition, the leaders of the Army Air Forces and the Manhattan Project began to plan for the actual delivery of the weapon. This led to the creation of the 509th Composite Group, originally based out of Wendover Field in Utah. The need for complete secrecy led the 509th to become a completely isolated and self-sufficient unit, hence the word “composite” in its name. In late 1944, future Enola Gay pilot Lt. Col. Paul Tibbets was given command over the newly formed unit, including complete control over recruiting the mechanics, pilots, navigators, and engineers necessary for the mission. His selections included some controversial characters, but were also among the best airmen that the United States had to offer. At its height in mid-1945, the 509th was comprised of 1, 767 personnel and 20 aircraft, predominantly located at its new base on Tinian Island in the South Pacific.
The demands on the 509th Composite Group were unique compared to every other air unit in the Second World War. It was the only bombardment group provided with the Silverplate B-29 Superfortress aircraft that were specially designed to be able to carry the large and heavy atomic bombs. The unit also participated in Project Alberta, the codenamed mission led by Navy Admiral Deak Parsons dedicated to the actual assembly of the atomic weapons on Tinian Island. Furthermore, in training for their mission, the 509th ran over 50 practice drops with “pumpkin bombs, ” fake bombs shaped identically to the atomic weapons. Of course, the 509th will always be remembered for its action on August 6, 1945, when Tibbets and his crew aboard the dropped the first uranium gun-type nuclear weapon on the city of Hiroshima in Japan. Three days later, the 509th’s Bockscar dropped a second atomic bomb on the city of Nagasaki. Japan announced its surrender a few days later, on August 15.
While these two units—the 509th Composite Group and the Special Engineering Detachment—were the largest and most prominent groups among the Manhattan Project’s military service members, others such as the Military Police and Provisional Engineering Detachment also provided vital services to the project’s overall success. The Military Police were responsible for the security of the complexes and the protection of its workers. This significant task was complicated by the intense secrecy of the Manhattan Project. A former member of the Military Police at Los Alamos, Lawrence Antos, described being left in the dark by his superiors: “They never really told us the goal of the Manhattan Project, they just said it would help end the war. But then we did later find out, when they detonated one of the bombs at Trinity.” These jobs were not as glamorous as those of the airmen or scientists, but without the help of military administration and support staff, the Manhattan Project’s security and overall progress may have been put into jeopardy.
The Manhattan Project remains a testament to scientific ingenuity and innovation, but without the contributions of its soldiers, sailors, and airmen, it would have never been possible. Today, the Atomic Heritage Foundation is proud to honor the military veterans of the Manhattan Project and all veterans who have served the United States.