Assured Access: A History of the United States Air Force Space Launch Enterprise, 1945-2020 [open pdf - 17MB]
From the Preface: "'Assured Access: A History of the United States Air Force Space Launch Enterprise, 1945-2020' is a study of more than six decades of Air Force launch support for the nation's military, intelligence, and civilian space communities. From their inception as refurbished ballistic missiles, Air Force boosters have launched national security space payloads for the Defense Department (DOD) and the National Reconnaissance Office (NRO), as well as for the National Aeronautics and Space Administration (NASA) and commercial and other civilian elements. Throughout this period, Air Force launch strategy has been to provide assured access to space by means of affordable, reliable, and responsive launch. Basic technology that produced the expendable launch space boosters of the early Cold War era changed little in fundamental engineering and manufacturing processes from that period until the advent of the evolved expendable launch vehicle (EELV) program at the turn of the new century. Expendable launch vehicles (ELV) had been the backbone of Air Force space flight until the arrival of the space shuttle, with its promise of routine access to space. By the early 1980s, that promise had become increasingly problematical as space shuttle development and launch rate promises failed to meet projected targets."
Air University: https://www.airuniversity.af.edu/