Frederick Ashworth (1912 - 2005) was a Vice Admiral in the US Navy.
Ashworth's work on the Manhattan Project began in 1944. Having already served in the Pacific theater, he was rotated back to the United States where he supervised the testing of bomb parts produced at Los Alamos.
Shortly after, he became director of operations for Project Alberta. He was responsible for choosing the base area of operations for the 509th Composite Group. After deliberating between Guam, Saipan, and Tinian, Ashworth settled on Tinian due to its proximity to Japan and superior facilities. Once the bombings were underway, he served as the weaponeer on the B-29 Bockscar, taking charge in the effort to drop Fat Man on Kokura. He soon had to change course after three bombing runs were thwarted by dense clouds of smoke. Ashworth made the decision to switch to the secondary target, and thus the bomb was dropped on Nagasaki. A brief interview conducted with Ashworth a few days after the Nagasaki mission is available here.
Following the completion of the mission, Ashworth was awarded the Silver Star Medal and the Legion of Merit. Ashworth continued to serve in the Navy, working with the Atomic Energy Commission. He eventually rose to the rank of Vice Admiral.