Clio Logo

Scientific research in Dayton that resulted in the initiator for the atomic bomb and a power source for spacecraft began during World War II. Work was done at a variety of isolated sites throughout the area. In the late 1940s, much of this work was consolidated at a new site in nearby Miamisburg. The Mound Laboratory, as the new site was called, was the U. S.’s first post-war Atomic Energy Commission site to be constructed. Research continued at the site until 2003. The Mound Laboratory is now home to the Mound Cold War Discovery Center, which aims to educate the public about the developments in scientific knowledge accomplished there.


  • Other research at the Mound Laboratory included looking at additional radionuclides (such as radium and thorium), studying radioisotopic thermoelectric generators, and non-nuclear activities. Photo from Dayton Daily News.
  • Inside the Mound Cold War Discovery Center. Photo from Dayton History.

The Dayton Unit Operations were established during World War II. Classified work with polonium, a rare chemical element, was carried out in isolated locations around Dayton, Ohio. The work resulted in the development of the initiator later used in the atomic bomb dropped in Nagasaki, Japan in 1945.  The Dayton Unit III, Unit IV, and “the Warehouse” continued hosting research and development through the early Cold War era.

Mound Laboratory, named for the nearby Adena mounds, was constructed in 1946 under the Manhattan Engineer District of the War Department. It was first used in 1948 or 1949 (sources differ), years after the production of polonium initiators by the Atomic Energy Commission began. The Mound’s purpose was to continue the work started by the Dayton Units, though it later expanded to other research, some of which is still classified today.

In 1961, Mound scientists started research on plutonium-238, which they believed could be used for electrical power on spacecraft. They developed units called Systems for Nuclear Auxiliary Power (SNAP) that have since been used for space missions and satellites. In 1994, SNAP became the sole focus of work done at Mound. Cleanup of the site began one year later, and all work at the site ended in 2003.

Hertweck, Jr., Floyd R. History. Mound Science and Energy Museum Association. Accessed December 01, 2018. https://moundmuseum.com/history/.

Dayton, OH. Atomic Heritage. Accessed December 01, 2018. https://www.atomicheritage.org/location/dayton-oh.

Mound Cold War Discovery Center. Dayton History. Accessed December 01, 2018. https://www.daytonhistory.org/visit/dayton-history-sites/mound-cold-war-discovery-center/. Information and photo source.

Powell, Lisa. SNEAK PEEK: Take a look inside Miamisburg’s new Mound Laboratories museum. Dayton Daily News. April 18, 2018. Accessed December 01, 2018. https://www.mydaytondailynews.com/news/local/sneak-peek-top-secrets-revealed-new-mound-laboratories-museum/zuoiMLUP3fAV2OVF7oZwHJ/. Photo source.