The effort to develop the Airborne Laser is based on over 25 years of scientific development in the Departments of Defense and Energy. It evolved primarily from Airborne Laser laboratory research to develop applications for high-energy lasers. This research culminated in a demonstration that showed that a low-power, short-range laser was capable of destroying a short-range air-to-air missile. Although this demonstration was considered militarily insignificant because of the laser’s low power and short range, it did succeed in identifying technologies that were necessary for the development of an operational Airborne Laser system. The research showed that an operational system would need optics that could compensate for the atmospheric turbulence that weakens and scatters a laser beam, optical devices that could withstand the heat produced by a high-energy laser without the added weight of water-cooling devices, and a new chemical laser with higher energy levels that would produce a stronger laser beam. In 1996, the Air Force launched the Airborne Laser program to develop a defensive system that could destroy enemy missiles from a distance of several hundred kilometers. Engineers determined that if they were to meet this requirement, the system would need a 14-module oxygen iodine laser. They also determined that the system would need a beam control/fire control assembly that could (1) safely move the laser beam through the aircraft, (2) shape the beam so that it was not scattered or weakened by the atmosphere, and (3) hold the beam on target, despite the movement of the aircraft. In addition, engineers determined that the system would need a battle management and control system capable of planning and executing an engagement. The Air Force planned to have the science and technology community develop extensive knowledge about the laser and beam control/fire control technologies before it launched an Airborne Laser acquisition program. However, according to the retired manager of the science and technology project, the budgets for technology efforts were limited, and the science and technology community could not fund the technology maturation effort. The Air Force knew that a program office was more likely to command the large budget needed to fully mature technologies, so it launched an acquisition program and assigned the program manager responsibility for both technology and product development. The program manager planned to demonstrate critical Airborne Laser technologies by first building a six-module version of the oxygen iodine laser, installing it along with other system components aboard a Boeing 747 aircraft (see fig. 1), and testing the capability of this scaled system in system-level flight tests. The tests would conclude in 2003 with an attempt to shoot down a short-range ballistic missile target at a distance of 100 kilometers. If this final test were successful, the Airborne Laser would have moved into product development. The Air Force launched the Airborne Laser acquisition program and identified cost and schedule goals before officials had the knowledge to make realistic projections. In 1996, when the program was launched, Department of Defense regulation 5000.2 required, and still requires today, that when a military service initiates a major acquisition program, it must establish cost and schedule goals. However, the Air Force could not make realistic estimates when it began the program because it had no way of knowing how much engineering effort would be needed to complete the development of technology critical to the system. Even today, some critical technologies that the system’s design depends upon remain immature, making it very difficult for analysts to determine how long it will take and how much it will cost to develop and produce the system. At the time the Airborne Laser program was launched, the laser and beam control/fire control technologies needed to develop the Airborne Laser system was immature. The Department of Defense’s science and technology community was actively researching and developing the laser and had produced a weak beam in a laboratory setting—but this major component had not reached the level of maturity needed to proceed into product development. The technology necessary to develop the beam control/fire control was even less advanced. Most of the scientists’ work was limited to analytical studies, wherein a few tests of laboratory hardware were linked together to work somewhat like the intended component. Because technology development is a process of discovery, the Air Force soon learned that there were too many unknowns regarding the development of Airborne Laser technology to make good cost and schedule estimates. As the technology development progressed, unanticipated technical challenges affected the program’s cost and schedule. Department of Defense analysts reported that the Airborne Laser program experienced cost and schedule growth because the program and its contractors underestimated the complexity of (1) designing laser components, (2) the system’s engineering analysis and design effort, and (3) engineering the system to fit on board the aircraft. As system development progressed and the Air Force gained a better understanding of the technical complexity of the system, the Air Force increased its cost and schedule estimates. The Air Force has made some progress in developing the Airborne Laser’s critical technologies, but many remain immature. We asked the Airborne Laser program office to determine the technologies most critical to the Airborne Laser system and to use technology readiness levels to assess the maturity of each. The officials determined that if the Airborne Laser is to meet the requirements established by the war fighters, then engineers must mature technologies in six areas, all of which are needed to successfully design the system. These technologies are devices that stabilize the laser system aboard the aircraft so that the beam can be maintained firmly on the target, optics—mirrors and windows—that focus and control the laser beam and allow it to pass safely through the aircraft, optical coatings that enhance the optics’ ability to pass laser energy through the system and to reflect the laser energy, hardware that works in tandem with computer software to actively track devices that measure atmospheric turbulence and compensate for it so that it does not scatter or weaken the laser beam, and safety systems that automatically shut down the high energy laser in the event of an emergency. At our request, the program office also assessed the maturity of the oxygen iodine laser. As figure 2 shows, program officials assessed the optical coatings at level five and the safety systems, atmospheric compensation, and target- tracking components at level six. At technology readiness level five, the technology being tested is incorporated into hardware whose form and fit are coming closer to that needed for an operational component and integrated with reasonable realistic supporting elements so that the technology can be tested in a simulated environment. At level six, the technology is incorporated into a prototype and tested in a high-fidelity laboratory environment or in a simulated operational environment. The program officials identified the optics and stabilizing devices as the least mature—at level four. At this level, engineers have shown that a technology is technically feasible but have not shown whether the technology will have the form, fit, or function required in the operational system. We agreed with all but one of the program officials’ assessments for these technologies. Our one disagreement centered on the maturity of the laser component of the system. While the program office assessed it at a technology readiness level of six, we consider the laser technology to be at level four because tests have been conducted only for a one-module laser in a controlled laboratory environment using surrogate components. For example, the tests used a stable laser resonator, rather than the unstable resonator that will be used in system-level flight tests. We also found that during tests of the one-module laser, the resonator was operating in multimode rather than single-mode. The resonator in the operational system will operate in single mode. Furthermore, the chemical storage and delivery subcomponents used in these tests were not representative of those that will be incorporated into the system’s design. According to program office officials, conducting a more realistic test would have cost time and money that were not available. Documents summarizing the tests of the one-module laser stated that the tests were successful in reducing the technical risks associated with the one-module system but that a new set of technical risks linked with developing a multimodule system must still be addressed during testing of the six-module system. In our opinion, the program office will demonstrate the laser technology in a relative environment (technology readiness level six) when the six-module system is integrated and successfully tested at full power within the high-fidelity laboratory environment of the Airborne Laser Systems Integration Laboratory, currently under construction at Edwards Air Force Base, California. According to the program office, this type of demonstration will not occur until February 2003. The Missile Defense Agency’s new strategy for developing the Airborne Laser incorporates some of the knowledge-based practices that characterize successful programs, but the agency would benefit from adopting another that would add greater discipline to its acquisition process. The new strategy allows more flexibility in setting requirements, makes time and facilities available to mature and test the critical technologies, and collects information needed to match the war fighters’ requirements to demonstrated technology. However, the agency has not established decision points with associated knowledge-based criteria for moving forward from (1) technology development to system integration, (2) system integration to system demonstration, and (3) system demonstration to production. At each of these points, the agency would stop to assess its knowledge and decide whether investment in the program’s next phase is warranted. The first new practice allows the Missile Defense Agency to refine requirements on the basis of the results of system engineering. The Department of Defense ordinarily faces significant hurdles in matching requirements to resources. The fundamental problem is twofold. First, under the department’s traditional process, requirements must be set before a program can be approved and a program must be approved before the product developer conducts systems engineering. Second, the competition for funding encourages requirements that will make the desired weapon system stand out from others. Consequently, many of the department’s product development programs include unrealistic requirements set by the user before the product developer has conducted the system engineering necessary to identify the time, technology, and money necessary to develop a product capable of meeting requirements. A second practice that is likely to improve the Airborne Laser’s development is making the time and facilities available to mature and test critical technologies.