Aerospace's early work in ballistic missiles was conducted through two divisions—the Missile Systems division and the Reentry Systems division. The Missile Systems division had three subdivisions: Advanced Minuteman, Advanced Systems, and Advanced Subsystems.
The Advanced Minuteman group investigated short- and long-term improvements to America's land-based ICBM operational force. This group directly supported the Air Force's Minuteman System Program Office through participation in the Minuteman Effectiveness Evaluation Group. Aerospace assisted studies by the Air Force and its primary contractor, TRW, that led to improvements in the Minuteman II and paved the way for the powerful multiple independently targeted reentry vehicle (MIRV) for the Minuteman III.
The Advanced Systems group provided a focal point for development of advanced weapon systems. The group identified and evaluated promising system concepts, performed preliminary designs, formulated cost and schedules, and helped prepare requests for proposals for the Air Force.
The Advanced Subsystems group sought to identify subsystems that would economically improve performance and reliability of ballistic missiles. Important improvements were made in areas such as guidance and control, command and control of missile systems in the field, propulsion, and basing. In addition, the group conducted extensive research on the effects of nuclear blasts on silos and missiles, including shock loads, debris clouds, and electromagnetic pulse. The electromagnetic pulse research helped to optimize the location and connection of the rebar in the silos' concrete and also provided confidence in the hardness estimates for superhard-silo basing proposals.
Aerospace's Reentry Systems Division was established in August 1964, when the technical operations at San Bernardino were reorganized to achieve functional alignment with Air Force activities. The task was to provide general systems engineering and technical support to the Air Force's Advanced Ballistic Re-Entry Systems (ABRES) program as well as the Army's Nike and Safeguard antiballistic missile programs. Initially, the primary objective of ABRES was to figure out how to penetrate Soviet antiballistic missile systems, which were undergoing significant testing and development at the time. In its most active period, ABRES would routinely flight-test 10 to 15 small-scale vehicles and four full-scale vehicles in a year.