Agencies within the national security space community recently have come under increasing pressure to conduct joint or interagency programs to take advantage of potentially shared objectives and mission synergies. Such joint endeavors, it is hoped, will make the agencies more efficient and effective and eliminate unnecessary redundancies among programs. However, a number of policy issues and challenges will influence how these efforts are executed. This report seeks to illuminate these policy issues and challenges, particularly those that will influence multi-mission space system concepts and programs conducted jointly by the National Reconnaissance Office (NRO) and the Air Force. Using case studies, this report examined five ways to conduct acquisition in an interagency setting-Executing Agent, System Integrator, Independent Agent, Confederation, and Joint Program Office. The report analyzed key elements inherent to interagency acquisition, including acquisition complexity, program management, program control, requirements management, funding stability, customer responsiveness, cultural alignment, and staffing. The report contained the following findings: Interagency efforts such as those conducted by the NRO and the Air Force need to maintain high-level support, not only from agency leadership but also from key stakeholders, users, and the Congress, and consistency with national policy guidance and objectives. Certain coordinating documents, such as the memorandum of agreement/memorandum of understanding, implementation plan and strategy, and program funding strategy are critical to ensuring commonality of purpose in the early stages of an interagency effort. Requirements management is critical, particularly in adjudicating among differing agency and user requirements to deter requirements creep by the partner agencies. Ensuring funding stability is important, especially when coordinating between two (or more) very different budgetary processes and timetables. Organizational culture can influence both operational capabilities and organizational structure and process, and its effects on interagency programs should not be underestimated.