Federal Systems Division «••*••• TRW Space & iifww Technology Group (NASA-CB-174905) SATELLITE VOICE BROADCAST N86-24677 SYSTEM S10DY, VCLDHE 2 Technical Beport, 11 Apr. 1984 - 11 Jul. 1S85 (TEW Space Technology Lafcs.) 335 p HC A15/MF A01 Unclas CSCL 178 G3/32 43072 Satellite Voice Broadcast System Study Volume 2 - Technical Report July 1985 Prepared for NASA Lewis Research Center 1 Report No 2 Government Accession No 3 Recipient's Catalog No CR 174905 4 Title and Subtitle 5 Report Date SATELLITE VOICE BROADCAST SYSTEM STUDY July 1985 VOLUME 2 - TECHNICAL REPORT 6 Performing Organization Code 7 Authors) 8 Performing Organization Report No Dr. Michael Horstein 10 Work Unit No 9. Performing Organization Name and Address 11 Contract or Grant No TRW Inc. One Space Park NAS3-24232 Redondo Beach, CA 90278 13 Type of Report and Period Covered 12. Sponsoring Agency Name and Address Contractor Report 4-11-84 through 7-11-85 National Aeronautics and Space Administration 14 Sponsoring Agency Code Washington, D.C., 20546 15 Supplementary Notes Contract Monitor Charles E. Provencher, Jr. NASA Lewis Research Center Cleveland, Ohio 16 Abstract This study investigates the feasibility of providing Voice of America (VOA) broad- casts by satellite relay, rather than via terrestrial relay stations. Satellite voice broadcast systems are described for three different frequency bands: HF (26 MHz), VHP (68 MHz), and L-band (1.5 GHz). The geographical areas of interest at HF and L-band include all major land masses worldwide with the exception of the U.S., Canada, and Australia. Geostationary satellite configurations are considerec for both frequency bands. In addition, a system of subsynchronous, circular satellites with an orbit period of 8 hours is developed for the HF band. VHF broadcasts, which are confined to the Soviet Union, are provided by a system of Molniya satellites. Satellites intended for HF or VHF broadcasting are extremely large and heavy. Sat ellite designs presented here are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. Even so, at HF it would take 47 geo- stationary satellites or 20 satellites in 8-hour orbits to fully satisfy the voice channel requirements of the broadcast schedule provided by VOA. On the other hand three Molniya satellites suffice for the geographically restricted schedule at VHF At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. Moreover, these satellites are comparable in size and weight to current satellites designed for direct broadcast of video program material. 7 Key Words (Suggested by Author(s)) 18 Distribution Statement Voice of America Satellite voice broadcasting Unclassified - unlimited Large space structures Phased-array antennas High-power transmitters 9 Security Classif (of this report) 20 Security Classif (of this page) 21 Mo of pages 22 Price' Unclassified Unclassified 319 *For sale by the National Technical Information Service, Springfield. Virginia 22161 Federal Systems Division II TRW Space & Technology Group Satellite Voice Broadcast System Study Volume 2 - Technical Report July 1985 Prepared for NASA Lewis Research Center Federal Systems Division TRW Space & Technology Group Satellite Voice Broadcast System Study Volume 2 — Technical Report July 1985 Contract No. NAS3-24232 TRW Space Prepared for: Technology Group NASA One Space Park Lewis Research Center Redondo Beach, CA 90278 21000 Brookpark Road Cleveland, Ohio 44135 Approved: M. florstein LEf Sharpies Project Manager Manager, Systems Engineering PREFACE This document is the final report of a 1-year study conducted by TRU Federal Systems Division for the NASA Lewis Research Center to determine satellite system designs, and associated life cycle costs, appropriate to Voice of America broadcasting needs. The report comprises three volumes. Volume 1 is an Executive Summary. Volume 2 contains the technical results of the study, together with a life cycle cost summary. Volume 3, which is labeled proprietary, contains non- recurring and first-unit cost estimates for the various satellite configu- rations generated during the study. R5-020-85 CONTRIBUTORS The following individuals made significant technical contributions in the areas indicated: W. Akle Satellite Configurations Antenna Structural Analysis Satellite Weight Estimation I. S. Cohen Transponder Technology S. H. Cushner Nonsatellite Broadcast Platforms M. Horstein Link Analysis System Synthesis and Evaluation J. L. Jennings Orbital Analysis J. D. Phillips Cost Analysis M. Swerdling Electrical Power Technology G. G. Wong RF Antenna Design R. E. Wong Project Planning L'Garde, Inc. of Newport Beach, California, as subcontractor to TRW, provided data on the performance of the inflatable antenna reflector. The technical study managers for NASA LeRC were Mr. G. H. Stevens and Mr. C. E. Provencher. Their guidance during the course of the study, together with that of Mr. B. E. LeRoy (Head, Satellite Systems Section), is deeply appreciated. 11 R5-02U-85 CONTENTS Page 1. INTRODUCTION 1-1 2. SYSTEM DESIGN METHODOLOGY 2-1 2.1 System Requirements 2-1 2.2 Baseline System Selection 2-4 2.3 Zonal Beam-Coverage Requirements 2-6 2.4 Channel Beam Concept 2-9 2.5 Satellite Capacity 2-17 2.6 System Design and Evaluation 2-20 3. BASELINE SYSTEM DEVELOPMENT 3-1 3.1 Geostationary System Development 3-1 3.2 Molniya System Development 3-6 3.3 8-Hour-Orbit System Development 3-10 3.4 Real-Time Feeder Links 3-25 4. SYSTEM CONCEPT VARIATIONS 4-1 4.1 Variation 1 — Coverage Restricted to Latitudes Between 40 Degrees North and 15 Degrees South 4-4 4.2 Variation 2 — Coverage Restricted to Latitudes Above 40 Degrees North or Below 15 Degrees South 4-8 4.3 Variation 3 — Single Channel Per Zone, Latitudes Above 40 degrees North or Below 15 Degrees South 4-13 4.4 Variation 4 — Single-Channel-Per-Zone, Prime-Time System 4-15 4.5 Summary of System Variations for Baseline Field Strength Requirements 4-22 4.6 Variation 5 — 150 uV/m field Strength Requirement 4-25 4.6.1 Geostationary System 4-25 4.6.2 Molniya System 4-25 4.6.3 Subsynchronous system 4-30 4.7 SSB-AM Band 1 System 4-42 5. LIFE CYCLE COST SUMMARY 5-1 5.1 Baseline System Life Cycle Costs 5-3 b.2 Variational System Life Cycle Costs 5-5 5.3 Life Cycle Costs for SSB-AM Band 1 Systems 5-11 i li R5-020-85 CONTENTS (Continued) ' Page 6. KEY SATELLITE TECHNOLOGIES 6-1 6.1 Antenna Technology 6-5 6.1.1 RF Aspects of Antenna Design 6-7 6.1.2 Structural Aspects of Antenna Design 6-15 6.2 Electrical Power Subsystem (EPS) 6-30 6.2.1 Primary Power Source Selection 6-30 6.2.2 Solar Array Area and Weight 6-33 6.2.3 Secondary Power Sources 6-38 6.2.4 Electrical Power Subsystem Weight 6-41 6.3 Transponder Technology 6-50 6.3.1 Power Amplifier Requirements 6-50 6.3.2 Power Amplifier Projections 6-52 6.3.3 Transponder Weight 6-53 6.3.4 Power or Channel Combining 6-55 7. PLANNING SUPPORT 7-1 7.1 Critical Technology 7-1 7.1.1 Large Deployable Antenna Technology 7-1 7.1.2 Electrical Power Subsystem 7-4 7.1.3 High-Power Transmitters 7-7 7.1.4 Thermal Control 7-8 7.1.5 Attitude Control 7-9 7.2 Project Plan 7-10 7.3 Critical Technology Cost and Schedule Risk 7-17 7.4 Satellite Cost and Schedule Risk 7-30 8. SINGLE-CHANNEL SATELLITE BROADCASTING SYSTEMS 8-1 8.1 Satellite Visibility 8-1 8.2 Representative OTV/Satellite Characteristics 8-19 9. CONCLUSIONS 9-1 IV R5-020-85 CONTENTS (Continued) Page APPENDIX A IONOSPHERIC PROPAGATION EFFECTS A-l APPENDIX B TECHNOLOGY TRADEOFFS B-l APPENDIX C SATELLITE RF POWER REQUIREMENTS C-l APPENDIX D SURVEY OF OTHER SOUND BROADCASTING ALTERNATIVES D-l APPENDIX E SATELLITE WEIGHT AND CAPACITY ESTIMATION E-l APPENDIX F SUBSYNCHRONOUS ORBIT COVERAGE CONTOURS F-l APPENDIX G BROADCAST SERVICE ALGORITHM 6-1 APPENDIX H COSTING METHODOLOGY H-l APPENDIX I SATELLITE WEIGHT BREAKDOWN 1-1 R5-020-85 ILLUSTRATIONS Page 1-1 Frequency Band Definition 1-3 2-1 Broadcast Zone Definition 2-2 2-2 Broadcast Schedule 2-3 2-3 Coverage of Zone 3 by 3-Degree Beams 2-8 2-4 Multiple-Beam Coverage From Molmya Orbit 2-11 2-5 Channel-Beam Concept 2-12 2-6 Modified Broadcast Schedule to Account for Satellite Beam Structure 2-14 2-7 Channel-Beam Demand of Modified Broadcast Schedule 2-15 2-8 Band 2 Channel-Beam Demand for Molniya Orbit Coverage 2-16 2-9 Determination of Satellite Channel-Beam Capacity 2-19 2-10 System Design Methodology 2-21 3-1 Geostationary Satellite Assignment 3-2 3-2 Geostationary Channel-Beam Demand 3-3 3-3 Single-Satellite Coverage from Molniya Orbit 3-7 3-4 Single-Satellite Coverage from Molniya Orbit 3-8 3-5a One-Hour Coverage Regions for 8-Hour Circular Orbit 3-11 3-5b One-Hour Coverage Regions for 8-Hour Circular Orbit 3-12 3-5c One-Hour Coverage Regions for 8-Hour Circular Orbit 3-13 3-6 Single-Satellite Coverage from 8-Hour Orbit 3-15 3-7 Single-Satellite Coverage from 8-Hour Orbit 3-17 3-8 Zonal Coverage Provided by a Pair of 8-Hour Satellites 3-18 3-9 Zonal Coverage Provided by Constellation of 20 8-Hour Satellites 3-20 3-10 Zonal Coverage Provided by Constellation of 20 8-Hour Satellites 3-21 3-11 Satellite/Zone Assignment Problem 3-23 3-12 Real-Time Feeder Links for 8-Hour Circular Orbit 3-27 3-13 Real-Time Feeder Links for 8-Hour Circular Orbit 3-28 3-14 Real-Time Feeder Links for Molniya Orbit 3-31 vi R5-020-85 ILLUSTRATIONS (Continued) Page 4-1 Broadcast Zone Redefinition for System Variations 1, 2, and 3 4-3 4-2 Channel-Beam Demand for Latitudes Between 40°N and 15°S 4-5 4-3 Geostationary Channel-Beam Demand for Latitudes Between 40°N and 15°S 4-6 4-4 Coverage from 8-Hour Orbit for Latitudes Between 40°N and 15°S 4-7 4-5 Channel-Beam Demand for Latitudes Above 40°N or Below 15°S 4-10 4-6 Coverage from 8-Hour Orbit for Latitudes Above 40°N or Below 15°S 4-11 4-7 Single-Satellite Channel-Beam.