He also receives an estimate of atomic bomb availability: Little Boy should be ready for use on Aug. In order of choice it is: Hiroshima, Kokura, and Niigata. Secretary of War Henry Stimson, in Potsdam for meeting between President Truman and Soviet Premier Stalin, receives current target list. President Harry Truman receives report on the successful Trinity test. The 509th Composite Group begins flying practice missions over Japan. Little Boy bomb units, accompanied by the U-235 projectile, are shipped out of San Francisco on the USS Indianapolis for Tinian Island. The 'Gadget,' an plutonium implosion device, detonates successfully in the Trinity test at Alamogordo, NM, demonstrating that the Fat Man atomic bomb design will work. Thanks to Clay Perkins and David Wargowski for their contributions to this timeline.
