Among the space activities of the last three decades satellite communications (SATCOM) has found the widest application in meeting both civil and military communications requirements. Several international, regional and national SATCOM systems of increasing capacity, capability and complexity have been and are being implemented over the years. The latest versions are utilizing such concepts as spot beams, processing transponders in SS-TDMA and operations in different frequency bands including the EHF band. On the military side, the United States of America, the United Kingdom, France and NATO (the North Atlantic Treaty Organisation) have been the only owners and operators of military SATCOM systems in the West. The systems in being and under development use satellites and ground terminals with characteristics which differ from the civilian ones with respect to frequency bands utilised and survivability and interoperability. The SATCOM has given the military users the potential of having much-needed mobility, flexibility and survivability in strategic and tactical communications for land, sea and air operations. It must, however, be said particularly for the military SATCOM systems that they have been evolved in big jumps, both in time and capability, each jump involving the deployment of two or three often specially designed large satellites, large expenses and rather traumatic transition between jumps. Despite these undesirable features these systems did not have the required degree of suevivability and flexibility.

Contributing Authors.- Preface.- Acknowledgments.- 1: INTRODUCTION.- 1.1 Objective and approach.- 1.2 Content of the book.- 2: CURRENT NATO COMMUNICATIONS PLANNING (SATCOM AND THE NATO C3 ARCHITECTURE).- 2.1 Planned evolution of the NICS.- 2.2 Implications of the C3 architecture for NATO SATCOM.- 2.3 Planned evolution of the NATO SATCOM system.- 2.4 Future requirements.- 2.5 References.- 3: COMPARISON OF NATO AND OTHER SYSTEMS.- 3.1 Objective.- 3.2 Services and system characteristics.- 3.3 Environmental factors.- 3.4 References.- 4: ISSUES AND FUTURE TRENDS IN SATELLITE COMMUNICATIONS.- 4.1 Objective.- 4.2 Issues.- 4.3 Responses.- 4.4 Areas to be considered.- 5: THREAT TO SATELLITE COMMUNICATIONS.- 5.1 The threat to NATO SATCOM post-2000.- 5.2 Uplink jamming.- 5.3 Downlink jamming.- 5.4 Interception.- 5.5 Nuclear threat.- 5.6 Physical attack.- 5.7 Piracy (unauthorized access).- 5.8 References.- 6: THREAT IMPLICATIONS AND COUNTER¬MEASURES.- 6.1 ECCM techniques.- 6.2 Information coding.- 6.3 Speech coding.- 6.4 Satellite hardening.- 6.5 References.- 7: ENVIRONMENT.- 7.1 Propagation factors.- 7.2 Precipitation effects.- 7.3 Frequency bands.- 7.4 Interference and noise.- 7.5 Countering propagation effects.- 7.6 References.- 8: TECHNOLOGY REVIEW.- 8.1 Device technologies for signal processing.- 8.2 Digital and SAW techniques for on-board processing.- 8.3 Spacecraft phased-array and MBA antennas.- 8.4 Solid-state spaceborne power amplifiers.- 8.5 Laser communications for intersatellite links.- 8.6 Laser communications to submerged submarines.- 8.7 Advanced materials for spacecraft.- 8.8 Superconductivity.- 8.9 Artificial intelligence and neural networks.- 8.10 Robotics and control.- 8.11 Power generation in space (*).- 8.12 Spacecraft propulsion systems.- 8.13 Spacetransportation.- 8.14 Earth station technology.- 8.15 Principles for selecting sponsored R & D projects.- 9: NATIONAL SATCOM SYSTEMS AND DEVELOPMENTS.- 9.1 Introduction.- 9.2 UK systems.- 9.3 Systems and developments in the USA.- 9.4 Canadian systems.- 9.5 French systems and developments.- 9.6 Systems of The Federal Republic of Germany.- 9.7 ESA systems.- 9.8 Russian systems.- 10: POSSIBLE SATCOM SYSTEM ARCHITECTURES.- 10.1 Desired characteristics.- 10.2 Inclined elliptical orbits (Molniya, Tundra, and Loopus types).- 10.3 Satellite cluster systems (CloudSat and MEWS).- 10.4 Tethered satellite systems.- 10.5 LightSat and proliferated LEO systems.- 10.6 Summary evaluation.- 10.7 Candidate architectures.- 10.8 References.- 11: COST-PERFORMANCE ANALYSIS.- 11.1 System features.- 11.2 Cost-performance comparison of candidate architectures.- 11.3 Approaches to cost reduction.- 12: CONCLUDING REMARKS.