In fiscal year 2003, the Department of Defense expects to spend more than $18 billion to develop, acquire, and operate satellites and other space-related systems. Satellite systems collect information on the capabilities and intentions of potential adversaries. They enable military forces to be warned of a missile attack and to communicate and navigate while avoiding hostile action. And they provide information that allows forces to precisely attack targets in ways that minimize collateral damage and loss of life. DOD's satellites also enable global communications, television broadcasts, weather forecasting; navigation of ships, planes, trucks, and cars; and synchronization of computers, communications, and electric power grids. Congress requested that we review reports we issued on satellite and other space-related programs over the past two decades and identify common problems affecting these programs. The majority of satellite programs cost more than expected and took longer to develop and launch than planned. In reviewing our past reports, we found that these results were commonly tied to the following problems. Requirements for what the satellite needed to do and how well it must perform were not adequately defined at the beginning of a program or were changed significantly once the program had already begun. Investment practices were weak. For example, potentially more cost-effective approaches were not examined and cost estimates were optimistic. Acquisition strategies were poorly executed. For example, competition was reduced for the sake of schedule or DOD did not adequately oversee contractors. Technologies were not mature enough to be included in product development. Several factors contributed to these problems. First, DOD often took a schedule-driven instead of a knowledge-driven approach to the acquisition process. As a result, activities essential to containing costs, maximizing competition among contractors and testing technologies were compressed or not done. Second, there is a diverse array of organizations with competing interests involved in overall satellite development--from the individual military services, to testing organizations, contractors, civilian agencies, and in some cases international partners. This created challenges in making tough tradeoff decisions, particularly since, for many years, there was no high-level official within the Office of the Secretary of Defense dedicated to developing and enforcing an overall investment strategy for space. Third, space acquisition programs have historically attempted to satisfy all requirements in a single step, regardless of the design challenge or the maturity of technologies to achieve the full capability. This approach made it difficult to match requirements to available resources (in terms of time, money, and technology). Other factors also created challenges for the satellite acquisition programs we reviewed. These include a shrinking industrial base, a declining space workforce, difficulties associated with testing satellites in a realistic environment, as well as challenges associated with launching satellites.