According to the Government Accountability Office, sustainment of weapon systems accounts for approximately 70 percent of the total life-cycle costs. When sustainment is not considered early in the development process or as an integral part of the systems engineering design, it can negatively affect the ability of the Air Force to maintain and improve the weapon system once it enters service. At the request of the Assistant Secretary of the Air Force for Acquisition, Technology, and Logistics, Weapons Systems Sustainment Planning Early in the Development Life Cycle identifies at what point or phase of the development of a weapons system sustainment planning should be integrated into the program, examines and provides recommendations regarding how sustainment planning should be evaluated throughout the development process, investigates and describes the current challenges with sustainment planning and determines what changes have occurred throughout the acquisition process that may have eroded sustainment planning, and identifies opportunities for acquisitions offices to gain greater access to sustainment expertise.