Among other matters, the congressionally mandated review  is to address the full range of ballistic missile threats to the United States,  deployed forces, friends, and allies; the organization, discharge, and  oversight of acquisition for ballistic missile defense programs; roles and  responsibilities of the Office of the Secretary of Defense, defense agencies,  combatant commands, the Joint Chiefs of Staff, and military departments  in such programs; DOD’s process for determining the force structure and  inventory objectives for ballistic missile defense programs; the near-term  and long-term affordability and cost-effectiveness of such programs; and  the role of international cooperation on missile defense in the ballistic  missile defense policy and strategy of the United States. DOD Identified Its Initial Ballistic Missile Defense Needs but Has Not Determined Its Overall Ballistic Missile Defense Requirements

DOD has identified its needs for establishing an initial and evolving  ballistic missile defense capability, but lacks the comprehensive analytic  basis needed to make fully informed decisions about the overall mix of  elements and interceptors that it requires. However, DOD’s assessments of missile defense requirements  prepared to date were limited in scope primarily because they were  prepared for specific purposes. The Joint Staff, for example, conducted  studies to identify the minimum interceptor quantities needed for certain  ballistic missile defense elements designed to defend against short-to- intermediate-range threats. Additionally, the combatant commands have  analyzed their ballistic missile defense requirements for their specific  regions, and the services have studied requirements for specific elements. Assessments of the threat and other risk assessments are also factors  affecting overall requirements for the types and quantities of missile  defense elements and interceptors. Force Structure Not Fully in Place for Some Units Operating Ballistic Missile Defense Elements

DOD has faced challenges in fully establishing units to operate five of the  eight ballistic missile defense elements that have been put into operational  use. DOD typically requires that major weapon systems be fielded with a  full complement of organized and trained personnel. To defend against  potentially catastrophic threats posed by rogue states armed with ballistic  missiles, however, DOD has in some cases put ballistic missile defense  elements into operational use before first ensuring that the military  services had created units and trained servicemembers to operate them. However, the five remaining elements that  have been put into operational use represent new capabilities designed  expressly for ballistic missile defense purposes and for which new  operational units had to be created. For example, the Army has faced personnel shortfalls to operate the  Ground-based Midcourse Defense element, which necessitated  augmentation with personnel from the Army National Guard to overcome  operational readiness concerns. MDA and the military services are taking steps to establish the  forces needed for operations, but this may take years for some elements. DOD recognizes the challenges created by putting elements into early use,  but has not set criteria requiring that operational units be in place before  new elements are made available for use. In the future, emerging threats or  crises could again require DOD to press developmental capabilities into  use. However, without fully  established organizations, personnel, and training, these units faced  challenges in dealing with the rapid fielding of elements, the ongoing  research and development activities involving fielded elements, and the  lack of an established force structure for operating the BMDS command  and control system. Lacking the solid foundation of a   knowledge-based, comprehensive analytic basis for making decisions,  which includes careful assessments of DOD’s overall ballistic missile  defense quantity requirements, DOD will continue to lack crucial data it  needs to make the best possible policy, strategy, and budgetary decisions  for ballistic missile defense. Looking forward,  reassessing this approach is important because DOD has several elements  in development that may be fielded in coming years, including additional  forward-based radars, the interceptors and radars that are planned for  fielding in Europe, and new elements associated with ascent phase  intercept. To determine the extent to which DOD has  identified the types and quantities of ballistic missile defense elements that  it requires, we identified, obtained, and reviewed key guidance, studies,  and analyses from the Office of the Secretary of Defense, Missile Defense  Agency (MDA), the Joint Staff, U.S. Strategic Command, other combatant  commands, and the military services.
Why GAO Did This Study

In 2002, the Department of Defense (DOD) began developing and rapidly fielding a global Ballistic Missile Defense System (BMDS) composed of elements that include radars, interceptors, and command and control systems. These elements are envisioned to be linked together to defend against a broad range of ballistic missile threats. In 2009, DOD began a broadly scoped review of missile defense policy and strategy intended to reassess the BMDS and set direction for the future. In response to congressional interest in missile defense requirements and operations, GAO reviewed the extent to which DOD has (1) identified the types and quantities of elements and interceptors it needs and (2) established the units to operate elements that have been put into use. GAO reviewed key analyses, studies, plans, and other documents from the Missile Defense Agency (MDA), the services, combatant commands, and Joint Staff; and interviewed officials from across DOD.

What GAO Found

DOD lacks the comprehensive analytic basis needed to make fully informed decisions about the types and quantities of elements and interceptors it needs. Such an analytic basis would include a comprehensive examination of the optimal mix of elements and interceptors needed to meet all of DOD's ballistic missile defense requirements. DOD studies prepared to date were completed for specific purposes, such as addressing regional threats. However, none of the studies have taken a comprehensive approach that addressed the full range of requirements. The Joint Staff conducted studies, for example, to identify the minimum interceptor quantities needed for certain ballistic missile defense elements designed to defend against short-to-intermediate-range threats. Additionally, the combatant commands have analyzed their ballistic missile defense requirements for their specific regions, and the services have studied requirements for specific elements. Without a full assessment of its overall requirements, DOD lacks the information it needs to make the best possible policy, strategy, and budgetary decisions for ballistic missile defense. DOD has faced challenges in fully establishing units to operate five of eight ballistic missile defense elements that have been put into operational use. DOD typically requires that major weapon systems be fielded with a full complement of organized and trained personnel. To rapidly field missile defenses, however, DOD has in some cases put ballistic missile defense elements into operational use before first ensuring that the military services had created units and trained servicemembers to operate them. Three of the eight elements were modifications to existing systems, like the Navy's Aegis ships, so units already existed to operate these modified elements. The five remaining elements--the midcourse defense system designed to defend the United States from long-range threats; the high-altitude, theater missile defense system; a powerful radar placed on a sea-based, movable platform; ground-based radars currently fielded in Japan and Israel; and the command and control system designed to link the BMDS together--were put into use before operational units were fully established. As a result, DOD has faced a number of challenges. For example, the Army faced personnel shortfalls to operate the midcourse defense system. These shortages affected the Army units' ability to support ongoing research and development activities and ultimately resulted in operational readiness concerns. MDA and the military services are taking steps to establish the needed forces, but this may take years for some elements. DOD recognizes the challenges created by putting elements into early use, but has not set criteria requiring that operational units be in place before new elements are made available for use. Looking ahead, several new elements are in development, like the radars and interceptors currently being considered for deployment in Europe, and emerging threats could again cause DOD to press those capabilities into use. Unless fully trained units are in place to support missile defense elements when they are made operational, DOD will continue to face uncertainties and operational risks associated with the elements.