The intelligence, surveillance, reconnaissance, and strike capabilities provided by unmanned aircraft systems have proven to be a key asset in accomplishing combat missions in the Middle East. DOD is planning to expand unmanned aircraft capabilities to include persistent ground attack, electronic warfare, suppression of enemy air defenses, cargo airlift, and other missions. Unmanned aircraft systems generally consist of (1) multiple aircraft, which can be expendable or recoverable and can carry lethal or nonlethal payloads; (2) a flight control station; (3) information and retrieval or processing stations; and (4) in some cases, wheeled land vehicles that carry launch and recovery platforms. Unmanned aircraft fall into one of three classes: small, tactical, and theater (see table 1). From 2002 through 2008, the total number of unmanned aircraft in DOD’s inventory increased from 167 to over 6,000. Most of the increase has been in small aircraft, with the more complex and expensive tactical and theater-level aircraft increasing from 127 to 521. Four major systems—Global Hawk, Predator, Reaper, and Shadow—have been deployed and used successfully in combat. Given this success, warfighters have demanded more systems and in many cases enhanced capabilities. However, we recently reported that some unmanned aircraft were not designed to meet joint service requirements or interoperability communications standards and, as a result, cannot easily exchange data, even within the same military service. Additionally, certain electromagnetic spectrum frequencies that are required for wireless communications are congested because a large number of unmanned aircraft and other weapons or communications systems use them simultaneously. Furthermore, DOD has been unable to fully optimize the use of its unmanned aircraft in combat operations because it lacks an approach to allocating and tasking them that considers the availability of all assets in determining how best to meet warfighter needs. To manage the increased demand for unmanned aircraft systems and encourage collaboration among the military services, the department has created the Office of Unmanned Warfare, the Unmanned Aircraft Systems Task Force, and other entities. In addition, DOD has published the Unmanned Systems Roadmap (Roadmap) that provides a framework for the future development of unmanned systems and related technologies. The Roadmap states that there is the potential for an unprecedented level of collaboration to meet capability needs and reduce acquisition costs by requiring greater commonality among the military services’ unmanned systems. We have reported that taking an open systems approach and designing systems with common subsystems and components can reduce both production and life cycle costs as well as improve interoperability among systems. For maximum benefit, commonality should be incorporated into the design of a system when requirements are being established. Unmanned aircraft systems can potentially achieve commonality in design and development, ranging from a complete system to a subsystem or component, as well as commonality in production facilities, tooling, and personnel. Despite the proven success of unmanned aircraft on the battlefield and the growing demand for them, these acquisitions continue to incur cost and schedule growth (see fig. 1). The cumulative development cost for the 10 programs we reviewed increased by over $3 billion, or 37 percent, from initial estimates. While 3 of the 10 programs had little or no development cost growth and 1 had a cost reduction, 6 experienced substantial growth ranging from 60 percent to 264 percent. In large part, this cost growth was the result of changes in program requirements and system designs after initiating development. Total procurement funding requirements have grown in the past because of increased quantities; however, many of the programs have also experienced growth in procurement unit costs. Finally, a number of these programs have experienced problems in testing and in performance that required additional development that contributed to cost growth and schedule delays (see app. II for more detailed information about each program). In most cases, development cost growth was the result of beginning system development with unclear or poorly defined requirements, immature technologies, and unstable designs—problems we have frequently found in other major acquisition programs. The Global Hawk program is a good example. In 2001, the Air Force began the Global Hawk program based on knowledge gained from a demonstration program and planned to incrementally integrate more advanced technologies over time. However, within a year, the Air Force fundamentally restructured and accelerated the program to pursue a larger and unproven airframe with multimission capability relying on immature technologies. The final design of the new airframe required more substantial changes than expected. Ultimately, frequent and substantive engineering changes drove development costs up nearly threefold. While BAMS has reported no cost growth, the program is just 1 year into its 7-year development, and the Navy plans to spend over $3 billion in development to modify the airframe—which is the existing Global Hawk airframe—and integrate payloads and other key equipment, modify ground stations, and purchase two developmental and three low rate production aircraft. BAMS program officials told us that they anticipate that the bulk of the development cost will result from modifying the size and shape of the existing radar payload to fit the Global Hawk airframe. Historically, similar weapons development efforts have had difficulty managing risk. Estimated development costs for MP-RTIP decreased 23 percent in large part because of a significant reduction in requirements caused by the termination of another aircraft program for which the radar was being developed. Procurement costs also increased for six of the seven systems that reported procurement cost data, a large portion of which is due to the planned procurement of additional aircraft (see table 2). For example, the Air Force planed to procure an additional 272 Predators, and the Army planed to procure an additional 84 Sky Warriors. As a result, unit costs for the Predator and Sky Warrior decreased by 41 percent and 9 percent, respectively. However, Reaper and Shadow had unit cost growth despite increased quantities. Reaper’s unit costs increased in part because requirements for missiles and a digital electronic engine control were added—which resulted in design changes and increased production costs. Unit cost increases in the Shadow program were largely the result of upgrades to the airframe that were needed to accommodate the size, weight, and power requirements for integrating a congressionally mandated data link onto the aircraft. The Army is also retrofitting fielded systems with capabilities that it had initially deferred, such as a heavy fuel engine. The procurement unit cost for Global Hawk increased the most, in large part because the Air Force not only increased the program’s requirements but also reduced the number of aircraft it intended to purchase. Four programs have also experienced delays in achieving initial operational capability by 1 to almost 4 years (see table 3). In some cases, program delays have been the result of expediting limited capability to the warfighter. For example, the production decision for the Sky Warrior was delayed by 2 years, and the Army now expects to deliver initial operational capability to the warfighter almost 4 years later than originally planned. Similarly, initial operational testing to prove the larger Global Hawk airframe works as intended has been delayed by nearly 3 years. Delays for these two programs and BAMS and Fire Scout average more than 27 months—6 months longer than the average delays we found in our recent assessment of other major weapons acquisitions. In contrast, the Reaper program expects to achieve initial operational capability 4 months earlier than originally planned—in large part because the Air Force expedited aircraft production to meet wartime demands. While Global Hawk, Predator, Reaper, and Shadow have been deployed with notable successes in theater—as well as identified lessons learned— rushing to field these capabilities resulted in a number of performance shortfalls and in some cases ultimately delayed meeting requirements. For example, Predator—the oldest program in our sample—directly transitioned from a successful technology demonstration program into production, skipping the development process entirely. Because little emphasis was placed on testing, performance requirements, and producibility, Predator experienced numerous problems when it was initially produced and deployed, such as unreliable communications and poor targeting accuracy. Given the importance of supporting combat operations, Global Hawk demonstrators and early production aircraft were also quickly placed into operational service. Program officials noted that as a result, the availability of test resources and time for testing were limited, which delayed the operational assessment of the original aircraft model by 3 years. Similarly, in February 2009, the Air Force reported that initial operational testing for the larger more capable Global Hawk aircraft and the program’s production readiness review had schedule breaches. Air Force officials cite the high level of concurrency between development, production, and testing; poor contractor performance; developmental and technical problems; system failures; and bad weather as key reasons for the most recent schedule breach. In a recent letter to the Global Hawk contractor, the Air Force’s Chief Acquisition Executive noted that unless the program’s problems are resolved quickly, the Air Force may have to consider deferring authorization of future production lots, terminating future modernization efforts, and canceling development and production of the aircraft that are planned to carry the MP-RTIP radar. According to program officials, they are currently in the process of developing a plan to address the schedule breaches. Consistent with DOD’s framework for acquiring unmanned systems, several of the tactical and theater-level unmanned aircraft acquisition programs we reviewed have identified areas of commonality to leverage resources and gain efficiencies. However, others share little in common and have missed opportunities to achieve commonality and efficiencies. Even those programs that have achieved some commonality may have additional opportunities to leverage resources. Table 4 compares the levels of commonality for three of our case examples. In assessing options for replacing an aging tactical unmanned aircraft system, the Marine Corps determined that the Army’s Shadow system could meet its requirements for reconnaissance, surveillance, and target acquisition capabilities without any service-unique modifications. An official from DOD’s Office of Unmanned Warfare emphasized that the Marine Corps believed that Shadow represented a “100 percent” solution.