 In July 1959 he was assigned to Headquarters U.S. Air Force where he served in the Office of the Deputy Chief of Staff for Materiel, as chief of the Defense Branch and later as chief, Weapon Systems Division; then was chief, Fighter Systems Staff Office, in the Office of the Deputy Chief of Staff for Systems and Logistics.In March 1962 O'Connor was assigned to the Air Force Systems Command and went to Norton Air Force Base, Calif., as deputy director of the Ballistic Systems Division.In November 1964 he became director of program management of the George C. Marshall Space Flight Center, NASA, Huntsville, Ala., where he was responsible for the management of Saturn/Apollo launch vehicle programs and that portion of the Saturn/Skylab program assigned to the Marshall Space Flight Center.