Conant was appointed to the National Defense Research Committee ( NDRC ) in 1940 , becoming its chairman in 1941 . In this capacity , he oversaw vital wartime research projects , including the development of synthetic rubber , and the Manhattan Project , which developed the first atomic bombs . On July 16 , 1945 , he was among the dignitaries present at the Alamogordo Bombing and Gunnery Range for the Trinity nuclear test , the first detonation of an atomic bomb , and was part of the Interim Committee that advised President Harry S. Truman to use atomic bombs on Japan . After the war , he served on the Joint Research and Development Board ( JRDC ) that was established to coordinate burgeoning defense research , and on the influential General Advisory Committee ( GAC ) of the Atomic Energy Commission ( AEC ) ; in the latter capacity he advised the president against starting a development program for the " hydrogen bomb "
Trinity nuclear test
Trinity (nuclear test)
James B. Conant