DOD is considering alternative approaches—including disaggregation—to providing space-based capabilities to address challenges related to high- cost satellite programs and increasing threats to its space system capabilities. The size, capability, and complexity of DOD’s satellites have tended to increase over the years, making them more costly to build. For example, Milstar, the protected communications satellite that preceded AEHF, weighed about 10,000 pounds, whereas the AEHF satellite weighs about 13,600 pounds and provides ten times the communications capacity. Additionally, SBIRS satellites are more capable than the Defense Support Program satellites they are to replace, offering greater sensor sensitivity and supporting a broader set of missions. According to DOD officials, it has made economic sense to maximize satellite capabilities as much as launch vehicle constraints would allow to fully utilize the capacity of the selected launch vehicle—which can cost well over $100 million for the vehicles DOD primarily uses. Additionally, certain requirements were consolidated to more efficiently provide capabilities, that is, fewer but more capable satellites could execute more missions than in the past. This approach of building large, multifunctional satellites also increased acquisition risks since the design and manufacturing of satellites became more complex. Total acquisition costs for the AEHF satellite constellation, for example, have more than doubled, from $6.7 billion at program inception in 2001 to $14.5 billion currently. This was partially due to the acquisition of an additional satellite, but also due to technical challenges and associated schedule delays of about 6 years for the launch of the first satellite. Our reports over the years have found that the significant cost and schedule growth for AEHF, SBIRS, and the environmental satellites DOD was acquiring in a similar fashion were partly due to design and manufacturing complexity. We also reported that DOD’s tendency to build large, monolithic satellites limited its ability to provide capabilities sooner and contributed to higher costs through developing extensive new designs, custom-made spacecraft, and payloads to meet the needs of multiple users. At the same time, other issues drove up costs for these programs including immature technologies, requirements instability, concurrent development and production, poor management and oversight, and reduced testing. We have reported that DOD has taken actions to address many of these issues, and in recent years, DOD has largely overcome cost and schedule problems for the programs currently in production, and additional satellites of the same design are now being launched. Reducing acquisition cost and risk are not the only reasons DOD is considering new approaches. According to Air Force Space Command, U.S. space systems face intentional and unintentional threats, which have increased rapidly over the past 20 years. These include radio frequency interference (including jamming), laser dazzling and blinding, kinetic intercept vehicles, and ground system attacks. Additionally, the hazards of the already-harsh space environment (e.g., extreme temperature fluctuations and radiation) have increased, including numbers of active and inactive satellites, spent rocket bodies, and other fragments and debris. In response, recent governmentwide and DOD strategic and policy guidance have stressed the need for U.S. space systems to be survivable or resilient against such threats. According to the Air Force, to maintain protected satellite communications, SBIRS, and space based environmental monitoring capabilities, new satellites and/or payloads would be needed beginning in 2024, 2025, and 2015, respectively. impacts of decisions could reach far beyond the space segment, affecting ground control systems, satellite user equipment, and communications networks. While this report is focused on the concept of disaggregation, it is important to note that DOD officials we spoke with stressed that disaggregation is only one of a number of approaches DOD is considering for its future space system designs. For example, in addition to disaggregation, DOD is considering the possibility of making satellites more maneuverable and building in defense capabilities to protect themselves as a means to increase survivability. Another approach under consideration is to evolve, or enhance, the capabilities of the large multifunctional satellites DOD is currently building. According to these officials, the primary considerations for studying these approaches and making decisions on which to use relate to finding the right balance between: Affordability—the determination that the life cycle cost of a program is in line with long-range plans; Resilience—the ability of a system to support the functions necessary for mission success in spite of hostile action or adverse conditions;and Capability—the ability to execute specified actions. To build consensus, and to conduct a more rigorous analysis of options, DOD is currently conducting studies that will consider future system architectures. Among these are Analyses of Alternatives (AOAs) that compare the effectiveness, suitability, risks, and estimated costs of alternatives for future protected satellite communications, SBIRS, and space-based environmental monitoring.design and components to pursue is critical because most of a program’s total life-cycle cost is influenced by decisions made before it is approved to start development. It is not yet known whether and to what extent disaggregation, on a broad scale, can enable DOD to reduce acquisition costs and increase the resilience of its satellite systems. DOD has had limited experience with disaggregating satellites and is still in the relatively early stages of quantifying the costs and benefits of disaggregating its satellites. The potential benefits of disaggregation, such as reduced costs associated with shorter development cycles and simpler designs, have been discussed in various Air Force publications. But less has been said about potential limitations, such as changes that would need to be made to interconnect systems—such as ground stations, user equipment, and communications networks—and the investment those changes would require. Moreover, many potential benefits can also be accompanied by drawbacks. For instance, with capabilities distributed across multiple platforms, rather than centralized onto just a few satellites, it may be more difficult for an adversary to target all assets to attack full system capabilities. However, with increased numbers of satellites, the space environment becomes more congested, increasing risk of radio frequency interference and the potential for on-orbit contact with and damage from debris or other assets. Given the breadth of impacts disaggregation can have, it may not be possible to have complete knowledge of its effects. But experts agree that decisionmaking would benefit from assessments that look well beyond a single satellite program. Further, even if DOD concludes disaggregation would have net positive effects, there are significant longstanding barriers to implementation. For instance, our work continues to find that there are time gaps—sometimes years—in aligning the delivery of satellites with associated user equipment and ground systems, which means that satellites may be in orbit for a long time with limited use. Without resolving the leadership, management, and oversight issues that have led to these delays, time gaps may well be exacerbated by disaggregation. Furthermore, disaggregation may require a more complex infrastructure and additional investments to support the satellites. DOD, civilian agencies, industry officials, and researchers have identified a broad range of potential benefits and limitations associated with disaggregating military space systems that span numerous aspects of space systems acquisitions and operations. Views on the potential benefits and limitations are widely distributed among the various experts, even within DOD. Because these potential effects are dependent on various disaggregation approaches and have not yet been validated in practice for large, complex space systems, some points may appear to contradict one another. Further, some potential effects may not be unique to disaggregation, but may also apply to other changes from the current approach. Tables 1 through 5 describe the potential benefits and limitations in terms of affordability and life cycle costs, resilience, capability, the acquisition process, and the industrial base identified by experts. The contents of the tables are not exhaustive, but each of the potential benefits and limitations included were identified by more than one expert as important considerations for deciding whether to pursue a disaggregated approach. Affordability—the feasibility of producing and supporting a program throughout its life cycle and within budget—is one of the key drivers behind considering disaggregation as an option, according to experts. Disaggregation may offer a more affordable approach to providing capabilities because of the potential for reduced per-satellite costs over the long term. Acquiring smaller, less complex satellites may require less time and effort to develop and produce, for example. This may be in part due to improved requirements discipline, as more frequent production rates may allow program managers to delay new requirements to the next production cycle instead of incorporating them into ongoing timelines mid- stream. However, a larger number of small satellites may be needed to provide the same level of capability overall, and the transition from existing system designs to disaggregation could increase costs in the near term. Additionally, given the current budget environment facing DOD, the transition to a new approach may be cost prohibitive, as resources may not be available to maintain and operate a legacy system and develop and field a new system at the same time. Table 1 describes how affordability could be impacted by disaggregation. Another main driver experts cited for examining disaggregation is the potential for increased resilience—the ability of a system to support the functions necessary for mission success in spite of hostile action or adverse conditions, according to one DOD definition—of space systems. Distributing capabilities across more satellites will increase the number and diversity of potential targets for an adversary and may make it more difficult for an adversary to decide which assets to attack, though some argue an adversary may be more likely to attack disaggregated satellites because they may be considered lower risk in terms of escalating hostilities. Potential effects of disaggregation in terms of resilience are listed in table 2. Experts also cite capability—the ability to execute specified actions—as a key driver for considering disaggregation. Some experts assert disaggregation will offer enhanced space-based capability, largely due to increased opportunities to insert new technologies, while others argue that disaggregation may reduce capability overall by losing the combined capacity achieved by operating multiple payloads on a single satellite. Table 3 details the range of potential benefits and limitations of disaggregation with respect to capability.