Harold J. Rider served as a 2nd lieutenant in the 393rd Bombardment Squadron of the 509th Composite Group. The 509th Composite Group was headed by Colonel Paul W. Tibbets and tasked with the deployment of the two nuclear bombs in August of 1945. Rider served as a navigator on the Enola Gay, but was not part of the mission that dropped the Little Boy bomb on the Japanese city of Hiroshima on August 6, 1945.