The Department of Defense (DoD) is considering major investments in systems that exploit information to support warfighting, and communications between users around the globe will be key to transmitting and using this information. In the near term, there are not enough military systems to satisfy projected communications demand and commercial systems will have to be used. In the future, budgetary pressures will make it difficult for the services to satisfy the projected communications demand with dedicated military assets. This report seeks to answer several questions: 1) How much of the projected demand can be met with programmed and planned military assets?; 2) Can commercial technologies, systems, or services meet the remaining needs? How do commercial communication assets compare with military assets in their ability to meet criteria important to DoD? What steps might be taken to mitigate shortfalls?; 3) What is the expected cost of providing the projected communications demand?; and, 4) What investment strategies should DoD employ to minimize the expected cost? The many categories of military communications include everything from battlefield communications between mobile users to communications between fixed sites in rear areas. Some of these communications must be survivable in a nuclear war, and others need high levels of protection from detection, interception, or jamming. Some require verv high data rates, whereas others need only low data rates. Some communications can be by wire or fiber optic cable, whereas others must use wireless means. We have examined a specific category of communications-high bandwidth, minimally protected satellite communications. This category of military demand represents roughly half of the projected military satellite capacity needs. To the extent that use of commercial systems can satisfy this need, military systems can be used for more specialized communications needing a greater level of control over their operation.