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1 Introduction and Background 1.1 CHANGING WORLD ORDER AND NATIONAL MILITARY STRATEGY The United States has planned its military capability and posture since the end of World War II to contain the spread of communism and deter aggression by the Soviet Union and associated communist states. Significant changes in the world order, most notably the collapse of communism in the Soviet Union and other Eastern European countries, the dissolution of the Warsaw Pact military alliance, the establishment of the Commonwealth of Independent States (CIS) (from the former Soviet Union), the reunification of Germany, and the emergence of independent and democratic governments around the globe, have prompted a significant change in this traditional defense approach. In August 1990, in an address in Aspen, Colorado, President Bush announced a new, regionally oriented national defense strategy that embodied four key elements: strategic deterrence and defense, forward presence, crisis response, and reconstitution. The disposition of nuclear weapons and delivery systems within the CIS and the proliferation of this technology to Third World countries remain uncertain and have prompted the need to maintain strong nuclear deterrent and defensive capabilities, including warning systems. The presence of U.S. forces throughout the world over the years has been effective in averting crises, preventing war, and demonstrating U.S. commitment to regional stability and prosperity. When forward presence has failed, however, U.S. forces have responded to regional crises on very short notice and have fought unilaterally or as part of a coalition. The United States, to continue responding in similar crises, must be capable of reconstituting a credible force—forming, training, and fielding new fighting units, activating the industrial base on a large scale, and maintaining a high level of technological advantage to oppose any potential adversary. Early in 1992, the Chairman of the Joint Chiefs of Staff provided strategic direction for the Armed Forces that reflected this new national defense strategy. He issued the 1992 National Military Strategy,1 which employed a set of strategic principles that encompassed a broad range of military areas, including readiness, collective security, arms control, maritime and aerospace superiority, strategic agility, power projection, technological superiority, and decisive force. He provided guidance on the planning and deployment of U.S. forces in responding to regional versus global threats and directed that operational planning be decentralized to the theater commanders-in-chief to the maximum extent possible, including the determination of force composition and recommended military strategies. A base force composed of four conceptual force packages—Strategic, Atlantic, Pacific, and U.S.-based Contingency Forces—was part of the strategy. These forces were supported by four key capabilities—space systems for warning, weather, surveillance, navigation, and communications; transportation systems to permit rapid deployment from U.S. bases to any region; reconstitution and mobilization capabilities on a large scale; and significant research and development capabilities to ensure technological superiority. 'TTze National Military Strategy, Chairman of the Joint Chiefs of Staff document, 1992 (unclassified). 5

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In September 1992, the Navy and Marine Corps, in support of the new National Military Strategy, issued a new directive for the naval service, entitled From the Sea,2 to provide naval expeditionary forces operating forward from the sea in joint service operations. The directive represented a fundamental shift from open-ocean warfighting to regional conflicts involving littoral operations. The document focused on naval forces operating globally in a forward presence posture with the capability to project power ashore as part of a joint U.S. military force in crisis response situations. Navy and Marine Corps command, control, and communications (C3) capabilities were identified as a key element of this new direction. The Naval Force Commander would require new capabilities either to command a joint task force or to host a Joint Task Force Commander. To achieve battlespace dominance in the sea, air, and land environments, this Commander, more than ever before, would have to rely on a highly capable C3 system that used U.S. and coalition space-based assets to support his tactical needs. 1.2 CHARGE TO THE SPACE PANEL Early in 1992, the Space Panel of the Naval Studies Board was asked by the Chief of Naval Operations (CNO) to conduct two concurrent studies that would suggest improvements in C3 capabilities and define new naval systems required to conduct future global power projection missions. The first task focused on surveillance, detection, identification, targeting, and battle damage assessment for targets expected in missions involving Third World or regional tactical conflicts. The results of this task are available in a separate report, entitled Space Support to Naval Tactical Operations,3 and provide specific recommendations for intelligence systems, weapon support, and coordination for precision strike against critical moving and stationary targets; and surveillance, target identification, and battle damage assessment from airborne and space platforms. The second task given to the Space Panel focused on naval communications. It was recognized that global power projection by naval forces would rely heavily on a communications capability to support voice and data traffic, surveillance and reconnaissance data exchange, Strike targeting information, and intelligence data needed for mission planning and precision targeting. The specific terms of reference given to the Space Panel for this second task are as follows: 2From the Sea, Navy and Marine Corps strategy document, Secretary of the Navy, September 28, 1992 (unclassified). 3Space Support to Naval Tactical Operations (U), classified report by the Space Panel's Task Group 1 (National Academy Press, Washington, D.C., 1993).

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Task 2—Naval Communications Architecture Reliable, flexible, and affordable communications will be critical to support future naval operations. This study will evaluate current Navy space communications, including ultra-high frequency (UHF), super-high frequency (SHF), and extremely high frequency (EHF) systems. The ability of the current and planned communications architecture to support global naval operations will be assessed. The future capability provided by MILSTAR and UHFFO systems will be evaluated, as well as the potential of future LIGHTS AT communications packages and the expanded use of civil and commercial systems. The unique communications needs of the Navy in polar regions and the ability of the current systems to support expanded strike operations in tactical, global conflicts will be evaluated. The study will attempt to define a future space communications architecture for the Navy that will allow the successful execution of global conflicts. The study will include the use of commercial systems and recognize that tactical and administrative communications traffic will use common systems for many future naval operations. The need for satellite to satellite crosslinks versus the use of ground relay sites to tie this architecture together will be addressed. Essentially, six specific areas were identified for investigation: (1) evaluate current Navy space communications systems, (2) evaluate planned military, civil, and commercial systems, (3) define a future global space communications architecture, (4) assess crosslink feasibility versus ground relay approaches, (5) evaluate current systems in expanded strike operations, and (6) assess current and planned Navy communications architectures. This report contains the results of the Task 2 study team effort that addressed these specific subjects. 1.3 APPROACH 1.3.1 Naval Communications and Scope of the Study Naval communications capabilities have evolved over the past several decades to use selected frequency bands over a wide portion of the electromagnetic spectrum, from extremely low frequencies (ELF) at tens of hertz (Hz) to extremely high frequencies (EHF) at tens of gigahertz (GHz). Radio frequency propagation characteristics, information bandwidth, and operational posture are the key parameters for selecting the frequency band of operation for a particular application. For example, communications to submarines use the lower frequency bands (ELF, VLF, and LF) to achieve seawater penetration of the signal to floating wire or towed buoy antennas at long distances (thousands of miles) when the platform is submerged. The information bandwidth at these frequencies, however, permits only low data rates, generally from a few bits per minute to roughly 50 bits per second (bps). Operation in the high frequency (HF) band allows increased data rates (up to a few kbps) at beyond line-of-sight distances using both ionospheric and ground wave propagation modes. One must move to the ultra-high frequency (UHF), super-high frequency (SHF), and extremely high frequency (EHF) bands to

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realize high information throughput (tens to thousands of kbps). However, in doing so the operator must be willing to deal with line-of-sight distances and atmospheric attenuation principally by water vapor, particularly at EHF frequencies. As indicated by the task, this study focused on naval space communications systems that operate in the UHF, SHF, and EHF frequency bands because of their capacity for high information throughput and global coverage by relays. The study considered the space, ground, and control elements of these systems. Because this work was conducted concurrent with Task 1, it was necessary to consider airborne relay platforms, especially when addressing the tactical situations involving deep strike missions. 1.3.2 Study Methodology The approach employed in this study is illustrated by Figure 1.1. To achieve a reasonable understanding of naval communications requirements, an effort was made to review naval missions and doctrine in light of the new strategies previously discussed. This effort also reviewed the results of the Task 1 study to incorporate any additional requirements that might emerge from the precision strike scenarios being considered. These requirements were then compared to the current and planned satellite communications capabilities of the Department of Defense (DOD), other government agencies, allied countries, and commercial sources to identify critical shortfalls and specific performance, technical, programmatic, organizational, or legal issues that exist with respect to the requirements identified earlier. TASK1 CURRENT & PLANNED CAPABILITIES POTENTIAL NEW CAPABILITIES & TECHNOLOGY OPPORTUNITIES GOAL ARCHITECTURE 1 -*- OPERATIONAL CAPABILITIES ENABLED ~r ^ COPERNICUS/CSS & TECHNOLOGY IMPACTS t >' RECOMMEN- DATIONS TASK1 T NAVY FIGURE 1.1 Study methodology to develop a goal naval communications architecture. 8

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A review of new satellite communications capabilities, particularly in the commercial sector, was conducted to ensure that all possible opportunities were considered in developing a goal naval communications architecture. This goal architecture was then identified based on consideration of current and planned military, civil, and commercial systems and the availability of new technology. The resulting goal architecture was then compared with operational requirements to determine what new tactical capabilities could be achieved if this architecture were implemented. This information was fed back to the Task 1 team so that new communications approaches would be incorporated into precision strike planning. It was also compared with the current Navy communications architecture, known as Copernicus, and the ongoing Communications Support System (CSS) project to identify similarities and/or differences for possible Navy consideration. These comparisons led to a series of specific recommendations to the Navy for consideration in developing satellite communications systems for the global power projection mission. 1.3.3 Glossary of Terms In the course of this study, it was necessary to develop a satellite communications systems taxonomy to ensure uniform use of terms among all study participants. Figure 1.2 provides a glossary of terms used in the study and an illustration of the key components of a multi-user satellite communications network. The terms are used extensively throughout this document and are provided here for the convenience of the reader. A more extensive list of acronyms and abbreviations is provided in the appendix. LINK —-^TTER"INAL LINK TERMINAL g_ - _ - LINK | NET EQUIPMENT I i USER • Communications: Information exchange among users (one-many, one-one, many-many) • Connectivity: A measure of the number of users that can exchange information • Network: A set of users organized for information exchange • Links: Means used to connect two or more users for communications — Can carry information (voice, video, facsimile, imagery, data) — At one or more frequencies (VHP, UHF, SHF, EHF) — Earth-to-space/air, space/air-to-earth, space/air-space/air • Circuits: Characterize links as one-way or two-way • Relays: Retransmit information and data received from one link on another • Terminals: Equipment employed by users to provide one or more links • Net Equipment: Equipment employed by users to constitute a network FIGURE 1.2 Naval communications architecture glossary of terms and network illustration.