Preface xxi
PART I SATELLITE TECHNOLOGY
1 Introduction to Satellites and their Applications 3
1.1 Ever-expanding Application Spectrum 3
1.2 What is a Satellite? 4
1.3 History of the Evolution of Satellites 7
1.3.1 Era of Hot Air Balloons and Sounding Rockets 7
1.3.2 Launch of Early Artificial Satellites 8
1.3.3 Satellites for Communications, Meteorology and Scientific Exploration -- Early Developments 10
1.3.4 Non-geosynchronous Communication Satellites: Telstar and Relay Programmes 11
1.3.5 Emergence of Geosynchronous Communication Satellites 12
1.3.6 International Communication Satellite Systems 15
1.3.7 Domestic Communication Satellite Systems 16
1.3.8 Satellites for other Applications also made Rapid Progress 19
1.3.9 Small or Miniature Satellites 22
1.4 Evolution of Launch Vehicles 27
1.5 Future Trends 33
1.5.1 Communication Satellites 33
1.5.2 Weather Forecasting Satellites 33
1.5.3 Earth Observation Satellites 33
1.5.4 Navigational Satellites 34
1.5.5 Military Satellites 35
Further Reading 35
Glossary 35
2 Satellite Orbits and Trajectories 37
2.1 Definition of an Orbit and a Trajectory 37
2.2 Orbiting Satellites -- Basic Principles 37
2.2.1 Newton's Law of Gravitation 39
2.2.2 Newton's Second Law of Motion 40
2.2.3 Kepler's Laws 41
2.3 Orbital Parameters 44
2.4 Injection Velocity and Resulting Satellite Trajectories 61
2.5 Types of Satellite Orbits 67
2.5.1 Orientation of the Orbital Plane 67
2.5.2 Eccentricity of the Orbit 68
2.5.3 Distance from Earth 70
2.5.4 Sun-synchronous Orbit 73
Further Readings 76
Glossary 76
3 Satellite Launch and In-orbit Operations 79
3.1 Acquiring the Desired Orbit 79
3.1.1 Parameters Defining the Satellite Orbit 80
3.1.2 Modifying the Orbital Parameters 83
3.2 Launch Sequence 95
3.2.1 Types of Launch Sequence 95
3.3 Launch Vehicles 100
3.3.1 Introduction 100
3.3.2 Classification 100
3.3.3 Anatomy of a Launch Vehicle 104
3.3.4 Principal Parameters 106
3.3.5 Major Launch Vehicles 108
3.4 Space Centres 127
3.4.1 Location Considerations 127
3.4.2 Constituent Parts of a Space Centre 128
3.4.3 Major Space Centres 129
3.5 Orbital Perturbations 144
3.6 Satellite Stabilization 146
3.6.1 Spin Stabilization 146
3.6.2 Three-axis or Body Stabilization 147
3.6.3 Comparison between Spin-stabilized and Three-axis Stabilized Satellites 149
3.6.4 Station Keeping 149
3.7 Orbital Effects on Satellite's Performance 149
3.7.1 Doppler Shift 149
3.7.2 Variation in the Orbital Distance 150
3.7.3 Solar Eclipse 150
3.7.4 Sun Transit Outrage 150
3.8 Eclipses 150
3.9 Look Angles of a Satellite 154
3.9.1 Azimuth Angle 154
3.9.2 Elevation Angle 155
3.9.3 Computing the Slant Range 156
3.9.4 Computing the Line-of-Sight Distance between Two Satellites 158
3.10 Earth Coverage and Ground Tracks 166
3.10.1 Satellite Altitude and the Earth Coverage Area 166
3.10.2 Satellite Ground Tracks 167
3.10.3 Orbit Inclination and Latitude Coverage 170
Further Readings 172
Glossary 172
4 Satellite Hardware 174
4.1 Satellite Subsystems 174
4.2 Mechanical Structure 175
4.2.1 Design Considerations 176
4.2.2 Typical Structure 176
4.3 Propulsion Subsystem 177
4.3.1 Basic Principle 178
4.3.2 Types of Propulsion System 178
4.4 Thermal Control Subsystem 185
4.4.1 Sources of Thermal Inequilibrium 186
4.4.2 Mechanism of Heat Transfer 186
4.4.3 Types of Thermal Control 187
4.5 Power Supply Subsystem 189
4.5.1 Types of Power System 189
4.5.2 Solar Energy Driven Power Systems 190
4.5.3 Batteries 195
4.6 Attitude and Orbit Control 199
4.6.1 Attitude Control 200
4.6.2 Orbit Control 200
4.7 Tracking, Telemetry and Command Subsystem 201
4.8 Payload 203
4.9 Antenna Subsystem 205
4.9.1 Antenna Parameters 207
4.9.2 Types of Antennas 210
4.10 Space Qualification and Equipment Reliability 224
4.10.1 Space Qualification 224
4.10.2 Reliability 225
Further Readings 226
Glossary 227
5 Communication Techniques 229
5.1 Types of Information Signals 229
5.1.1 Voice Signals 230
5.1.2 Data Signals 230
5.1.3 Video Signals 230
5.2 Amplitude Modulation 231
5.2.1 Frequency Spectrum of the AM Signal 232
5.2.2 Power in the AM Signal 233
5.2.3 Noise in the AM Signal 233
5.2.4 Different Forms of Amplitude Modulation 235
5.3 Frequency Modulation 241
5.3.1 Frequency Spectrum of the FM Signal 243
5.3.2 Narrow Band and Wide Band FM 245
5.3.3 Noise in the FM Signal 246
5.3.4 Generation of FM Signals 250
5.3.5 Detection of FM Signals 252
5.4 Pulse Communication Systems 259
5.4.1 Analogue Pulse Communication Systems 259
5.4.2 Digital Pulse Communication Systems 261
5.5 Sampling Theorem 265
5.6 Shannon--Hartley Theorem 266
5.7 Digital Modulation Techniques 267
5.7.1 Amplitude Shift Keying (ASK) 268
5.7.2 Frequency Shift Keying (FSK) 268
5.7.3 Phase Shift Keying (PSK) 269
5.7.4 Differential Phase Shift Keying (DPSK) 270
5.7.5 Quadrature Phase Shift Keying (QPSK) 271
5.7.6 Offset QPSK 273
5.7.7 8PSK and 16PSK 274
5.7.8 Quadrature Amplitude Modulation (QAM) 274
5.7.9 Amplitude Phase Shift Keying (APSK) 276
5.8 Multiplexing Techniques 277
5.8.1 Frequency Division Multiplexing 277
5.8.2 Time Division Multiplexing 279
5.8.3 Code Division Multiplexing 281
Further Readings 282
Glossary 283
6 Multiple Access Techniques 286
6.1 Introduction to Multiple Access Techniques 286
6.1.1 Transponder Assignment Modes 287
6.2 Frequency Division Multiple Access (FDMA) 288
6.2.1 Demand Assigned FDMA 290
6.2.2 Pre-assigned FDMA 290
6.2.3 Calculation of C/N Ratio 290
6.3 Single Channel Per Carrier (SCPC) Systems 293
6.3.1 SCPC/FM/FDMA System 293
6.3.2 SCPC/PSK/FDMA System 294
6.4 Multiple Channels Per Carrier (MCPC) Systems 295
6.4.1 MCPC/FDM/FM/FDMA System 295
6.4.2 MCPC/PCM-TDM/PSK/FDMA System 296
6.5 Time Division Multiple Access (TDMA) 297
6.6 TDMA Frame Structure 297
6.6.1 Reference Burst 298
6.6.2 Traffic Burst 298
6.6.3 Guard Time 299
6.7 TDMA Burst Structure 299
6.7.1 Carrier and Clock Recovery Sequence 299
6.7.2 Unique Word 299
6.7.3 Signalling Channel 300
6.7.4 Traffic Information 301
6.8 Computing Unique Word Detection Probability 301
6.9 TDMA Frame Efficiency 302
6.10 Control and Coordination of Traffic 303
6.11 Frame Acquisition and Synchronization 305
6.11.1 Extraction of Traffic Bursts from Receive Frames 305
6.11.2 Transmission of Traffic Bursts 305
6.11.3 Frame Synchronization 305
6.12 FDMA vs. TDMA 307
6.12.1 Advantages of TDMA over FDMA 308
6.12.2 Disadvantages of TDMA over FDMA 308
6.13 Code Division Multiple Access (CDMA) 308
6.13.1 DS-CDMA Transmission and Reception 309
6.13.2 Frequency Hopping CDMA (FH-CDMA) System 311
6.13.3 Time Hopping CDMA (TH-CDMA) System 313
6.13.4 Comparison of DS-CDMA, FH-CDMA and TH-CDMA Systems 314
6.14 Space Domain Multiple Access (SDMA) 316
6.14.1 Frequency Re-use in SDMA 316
6.14.2 SDMA/FDMA System 317
6.14.3 SDMA/TDMA System 318
6.14.4 SDMA/CDMA System 319
Further Readings 319
Glossary 320
7 Satellite Link Design Fundamentals 322
7.1 Transmission Equation 322
7.2 Satellite Link Parameters 324
7.2.1 Choice of Operating Frequency 324
7.2.2 Propagation Considerations 324
7.2.3 Noise Considerations 325
7.2.4 Interference-related Problems 325
7.3 Frequency Considerations 326
7.3.1 Frequency Allocation and Coordination 326
7.4 Propagation Considerations 330
7.4.1 Free-space Loss 330
7.4.2 Gaseous Absorption 331
7.4.3 Attenuation due to Rain 333
7.4.4 Cloud Attenuation 334
7.4.5 Signal Fading due to Refraction 334
7.4.6 Ionosphere-related Effects 335
7.4.7 Fading due to Multipath Signals 338
7.5 Techniques to Counter Propagation Effects 341
7.5.1 Attenuation Compensation Techniques 341
7.5.2 Depolarization Compensation Techniques 342
7.6 Noise Considerations 342
7.6.1 Thermal Noise 342
7.6.2 Noise Figure 343
7.6.3 Noise Temperature 344
7.6.4 Noise Figure and Noise Temperature of Cascaded Stages 345
7.6.5 Antenna Noise Temperature 346
7.6.6 Overall System Noise Temperature 350
7.7 Interference-related Problems 353
7.7.1 Intermodulation Distortion 354
7.7.2 Interference between the Satellite and Terrestrial Links 357
7.7.3 Interference due to Adjacent Satellites 357
7.7.4 Cross-polarization Interference 361
7.7.5 Adjacent Channel Interference 361
7.8 Antenna Gain-to-Noise Temperature (G/T) Ratio 365
7.9 Link Design 367
7.9.1 Link Design Procedure 368
7.9.2 Link Budget 368
7.10 Multiple Spot Beam Technology 371
Further Readings 374
Glossary 375
8 Earth Station 378
8.1 Earth Station 378
8.2 Types of Earth Station 380
8.2.1 Fixed Satellite Service (FSS) Earth Station 381
8.2.2 Broadcast Satellite Service (BSS) Earth Stations 382
8.2.3 Mobile Satellite Service (MSS) Earth Stations 383
8.2.4 Single Function Stations 384
8.2.5 Gateway Stations 385
8.2.6 Teleports 386
8.3 Earth Station Architecture 386
8.4 Earth Station Design Considerations 387
8.4.1 Key Performance Parameters 388
8.4.2 Earth Station Design Optimization 390
8.4.3 Environmental and Site Considerations 391
8.5 Earth Station Testing 392
8.5.1 Unit and Subsystem Level Testing 392
8.5.2 System Level Testing 392
8.6 Earth Station Hardware 398
8.6.1 RF Equipment 398
8.6.2 IF and Baseband Equipment 408
8.6.3 Terrestrial Interface 409
8.7 Satellite Tracking 412
8.7.1 Satellite Tracking System -- Block Diagram 412
8.7.2 Tracking Techniques 412
8.8 Some Representative Earth Stations 419
8.8.1 Goonhilly Satellite Earth Station 419
8.8.2 Madley Communications Centre 421
8.8.3 Madrid Deep Space Communications Complex 421
8.8.4 Canberra Deep Space Communications Complex 422
8.8.5 Goldstone Deep Space Communications Complex 423
8.8.6 Honeysuckle Creek Tracking Station 424
8.8.7 Kaena Point Satellite Tracking Station 426
8.8.8 Bukit Timah Satellite Earth Station 426
8.8.9 INTELSAT Teleport Earth Stations 426
8.8.10 SUPARCO Satellite Ground Station 428
8.8.11 Makarios Satellite Earth Station 428
8.8.12 Raisting Earth Station 428
8.8.13 Indian Deep Space Network 429
Glossary 430
9 Networking Concepts 433
9.1 Introduction 433
9.2 Network Characteristics 433
9.2.1 Availability 434
9.2.2 Reliability 434
9.2.3 Security 435
9.2.4 Throughput 436
9.2.5 Scalability 437
9.2.6 Topology 437
9.2.7 Cost 437
9.3 Applications and Services 437
9.3.1 Satellite and Network Services 438
9.3.2 Satellite Services 438
9.3.3 Network Services 438
9.3.4 Internet Services 439
9.4 Network Topologies 442
9.4.1 Bus Topology 442
9.4.2 Star Topology 443
9.4.3 Ring Topology 444
9.4.4 Mesh Topology 444
9.4.5 Tree Topology 445
9.4.6 Hybrid Topology 446
9.5 Network Technologies 447
9.5.1 Circuit Switched Networks 447
9.5.2 Packet Switched Networks 448
9.5.3 Circuit Switched versus Packet Switched Networks 449
9.6 Networking Protocols 450
9.6.1 Common Networking Protocols 450
9.6.2 The Open Systems Interconnect (OSI) Reference Model 453
9.6.3 Internet Protocol (IP) 456
9.6.4 Transmission Control Protocol (TCP) 457
9.6.5 Hyper Text Transfer Protocol (HTTP) 457
9.6.6 File Transfer Protocol (FTP) 457
9.6.7 Simple Mail Transfer Protocol (SMTP) 458
9.6.8 User Datagram Protocol (UDP) 458
9.6.9 Asynchronous Transfer Mode (ATM) 459
9.7 Satellite Constellations 459
9.7.1 Constellation Geometry 459
9.7.2 Major Satellite Constellations 460
9.8 Internetworking with Terrestrial Networks 465
9.8.1 Repeaters, Bridges, Switches and Routers 465
9.8.2 Protocol Translation, Stacking and Tunnelling 466
9.8.3 Quality of Service 466
Further Readings 467
Glossary 467
PART II SATELLITE APPLICATIONS
10 Communication Satellites 473
10.1 Introduction to Communication Satellites 473
10.2 Communication-related Applications of Satellites 474
10.2.1 Geostationary Satellite Communication Systems 475
10.2.2 Non-geostationary Satellite Communication Systems 475
10.3 Frequency Bands 475
10.4 Payloads 475
10.4.1 Types of Transponders 477
10.4.2 Transponder Performance Parameters 478
10.5 Satellite versus Terrestrial Networks 479
10.5.1 Advantages of Satellites Over Terrestrial Networks 479
10.5.2 Disadvantages of Satellites with Respect to Terrestrial Networks 480
10.6 Satellite Telephony 481
10.6.1 Point-to-Point Trunk Telephone Networks 482
10.6.2 Mobile Satellite Telephony 482
10.7 Satellite Television 484
10.7.1 A Typical Satellite TV Network 484
10.7.2 Satellite--Cable Television 485
10.7.3 Satellite--Local Broadcast TV Network 486
10.7.4 Direct-to-Home Satellite Television 487
10.7.5 Digital Video Broadcasting (DVB) 490
10.7.6 DVB-S and DVB-S2 Standards 491
10.7.7 DVB-RCS and DVB-RCS2 Standards 493
10.7.8 DVB-T and DVB-T2 Standards 493
10.7.9 DVB-H and DVB-SH Standards 494
10.8 Satellite Radio 496
10.9 Satellite Data Communication Services 496
10.9.1 Satellite Data Broadcasting 496
10.9.2 VSATs (Very Small Aperture Terminals) 497
10.10 Important Missions 502
10.10.1 International Satellite Systems 502
10.10.2 Regional Satellite Systems 512
10.10.3 National Satellite Systems 513
10.11 Future Trends 514
10.11.1 Development of Satellite Constellations in LEO Orbits 516
10.11.2 Development of Personal Communication Services (PCS) 516
10.11.3 Use of Higher Frequency Bands 517
10.11.4 Development of Light Quantum Communication Techniques 517
10.11.5 Development of Broadband Services to Mobile Users 517
10.11.6 Development of Hybrid Satellite/Terrestrial Networks 517
10.11.7 Advanced Concepts 518
Further Readings 519
Glossary 521
11 Remote Sensing Satellites 524
11.1 Remote Sensing -- An Overview 524
11.1.1 Aerial Remote Sensing 525
11.1.2 Satellite Remote Sensing 525
11.2 Classification of Satellite Remote Sensing Systems 526
11.2.1 Optical Remote Sensing Systems 526
11.2.2 Thermal Infrared Remote Sensing Systems 528
11.2.3 Microwave Remote Sensing Systems 529
11.3 Remote Sensing Satellite Orbits 531
11.4 Remote Sensing Satellite Payloads 531
11.4.1 Classification of Sensors 531
11.4.2 Sensor Parameters 534
11.5 Passive Sensors 535
11.5.1 Passive Scanning Sensors 536
11.5.2 Passive Non-scanning Sensors 539
11.6 Active Sensors 540
11.6.1 Active Non-scanning Sensors 540
11.6.2 Active Scanning Sensors 540
11.7 Types of Images 542
11.7.1 Primary Images 542
11.7.2 Secondary Images 542
11.8 Image Classification 545
11.9 Image Interpretation 546
11.9.1 Interpreting Optical and Thermal Remote Sensing Images 546
11.9.2 Interpreting Microwave Remote Sensing Images 547
11.9.3 GIS in Remote Sensing 547
11.10 Applications of Remote Sensing Satellites 548
11.10.1 Land Cover Classification 548
11.10.2 Land Cover Change Detection 549
11.10.3 Water Quality Monitoring and Management 550
11.10.4 Flood Monitoring 551
11.10.5 Urban Monitoring and Development 552
11.10.6 Measurement of Sea Surface Temperature 552
11.10.7 Deforestation 553
11.10.8 Global Monitoring 553
11.10.9 Predicting Disasters 555
11.10.10 Other Applications 558
11.11 Major Remote Sensing Missions 558
11.11.1 Landsat Satellite System 558
11.11.2 SPOT Satellite System 561
11.11.3 Radarsat Satellite System 564
11.11.4 Indian Remote Sensing Satellite System 565
11.12 Future Trends 573
Further Readings 574
Glossary 575
12 Weather Satellites 577
12.1 Weather Forecasting -- An Overview 577
12.2 Weather Forecasting Satellite Fundamentals 580
12.3 Images from Weather Forecasting Satellites 580
12.3.1 Visible Images 580
12.3.2 IR Images 582
12.3.3 Water Vapour Images 583
12.3.4 Microwave Images 584
12.3.5 Images Formed by Active Probing 585
12.4 Weather Forecasting Satellite Orbits 586
12.5 Weather Forecasting Satellite Payloads 587
12.5.1 Radiometer 588
12.5.2 Active Payloads 589
12.6 Image Processing and Analysis 592
12.6.1 Image Enhancement Techniques 592
12.7 Weather Forecasting Satellite Applications 593
12.7.1 Measurement of Cloud Parameters 594
12.7.2 Rainfall 594
12.7.3 Wind Speed and Direction 595
12.7.4 Ground-level Temperature Measurements 596
12.7.5 Air Pollution and Haze 596
12.7.6 Fog 596
12.7.7 Oceanography 596
12.7.8 Severe Storm Support 597
12.7.9 Fisheries 598
12.7.10 Snow and Ice Studies 598
12.8 Major Weather Forecasting Satellite Missions 599
12.8.1 GOES Satellite System 599
12.8.2 Meteosat Satellite System 605
12.8.3 Advanced TIROS-N (ATN) NOAA Satellites 608
12.9 Future of Weather Forecasting Satellite Systems 612
Further Readings 612
Glossary 613
13 Navigation Satellites 614
13.1 Development of Satellite Navigation Systems 614
13.1.1 Doppler Effect based Satellite Navigation Systems 615
13.1.2 Trilateration-based Satellite Navigation Systems 615
13.2 Global Positioning System (GPS) 621
13.2.1 Space Segment 621
13.2.2 Control Segment 622
13.2.3 User Segment 623
13.3 Working Principle of the GPS 625
13.3.1 Principle of Operation 625
13.3.2 GPS Signal Structure 627
13.3.3 Pseudorange Measurements 628
13.3.4 Determination of the Receiver Location 629
13.4 GPS Positioning Services and Positioning Modes 631
13.4.1 GPS Positioning Services 631
13.4.2 GPS Positioning Modes 632
13.5 GPS Error Sources 634
13.6 GLONASS Satellite System 637
13.6.1 GLONASS Segments 638
13.6.2 GLONASS Signal Structure 639
13.7 GPS-GLONASS Integration 641
13.8 EGNOS Satellite Navigation System 642
13.9 Galileo Satellite Navigation Systems 645
13.9.1 Three-Phase Development Programme 645
13.9.2 Services 646
13.10 Indian Regional Navigational Satellite System (IRNSS) 647
13.11 Compass Satellite Navigation System 648
13.12 Hybrid Navigation Systems 648
13.13 Applications of Satellite Navigation Systems 650
13.13.1 Military Applications 650
13.13.2 Civilian Applications 651
13.14 Future of Satellite Navigation Systems 654
Further Readings 655
Glossary 656
14 Scientific Satellites 658
14.1 Satellite-based versus Ground-based Scientific Techniques 658
14.2 Payloads on Board Scientific Satellites 659
14.2.1 Payloads for Studying Earth's Geodesy 659
14.2.2 Payloads for Earth Environment Studies 660
14.2.3 Payloads for Astronomical Studies 661
14.3 Applications of Scientific Satellites -- Study of Earth 665
14.3.1 Space Geodesy 665
14.3.2 Tectonics and Internal Geodynamics 669
14.3.3 Terrestrial Magnetic Fields 670
14.4 Observation of the Earth's Environment 670
14.4.1 Study of the Earth's Ionosphere and Magnetosphere 671
14.4.2 Study of the Earth's Upper Atmosphere (Aeronomy) 677
14.4.3 Study of the Interaction between Earth and its Environment 679
14.5 Astronomical Observations 680
14.5.1 Observation of the Sun 681
14.6 Missions for Studying Planets of the Solar System 686
14.6.1 Mercury 691
14.6.2 Venus 692
14.6.3 Mars 694
14.6.4 Outer Planets 697
14.6.5 Moon 703
14.6.6 Asteroids 705
14.6.7 Comets 706
14.7 Missions Beyond the Solar System 707
14.8 Other Fields of Investigation 710
14.8.1 Microgravity Experiments 710
14.8.2 Life Sciences 711
14.8.3 Material Sciences 712
14.8.4 Cosmic Ray and Fundamental Physics Research 713
14.9 Future Trends 714
Further Readings 715
Glossary 715
15 Military Satellites 717
15.1 Military Satellites -- An Overview 717
15.1.1 Applications of Military Satellites 718
15.2 Military Communication Satellites 718
15.3 Development of Military Communication Satellite Systems 719
15.3.1 American Systems 720
15.3.2 Russian Systems 724
15.3.3 Satellites Launched by other Countries 725
15.4 Frequency Spectrum Utilized by Military Communication Satellite Systems 726
15.5 Dual-use Military Communication Satellite Systems 727
15.6 Reconnaisance Satellites 728
15.6.1 Image Intelligence or IMINT Satellites 728
15.7 SIGINT Satellites 732
15.7.1 Development of SIGINT Satellites 733
15.8 Early Warning Satellites 735
15.8.1 Major Early Warning Satellite Programmes 736
15.9 Nuclear Explosion Satellites 738
15.10 Military Weather Forecasting Satellites 738
15.11 Military Navigation Satellites 739
15.12 Space Weapons 739
15.12.1 Classification of Space Weapons 740
15.13 Strategic Defence Initiative 745
15.13.1 Ground Based Programmes 746
15.13.2 Directed Energy Weapon Programmes 749
15.13.3 Space Programmes 751
15.13.4 Sensor Programmes 752
15.14 Directed Energy Laser Weapons 752
15.14.1 Advantages 753
15.14.2 Limitations 753
15.14.3 Directed Energy Laser Weapon Components 754
15.14.4 Important Design Parametres 755
15.14.5 Important Laser Sources 756
15.14.6 Beam Control Technology 763
15.15 Advanced Concepts 764
15.15.1 New Surveillance Concepts Using Satellites 765
15.15.2 Long Reach Non-lethal Laser Dazzler 765
15.15.3 Long Reach Laser Target Designator 766
Further Readings 767
Glossary 767
16 Emerging Trends 769
16.1 Introduction 769
16.2 Space Tethers 769
16.2.1 Space Tethers -- Different Types 770
16.2.2 Applications 774
16.2.3 Space Tether Missions 775
16.2.4 Space Elevator 779
16.3 Aerostat Systems 781
16.3.1 Components of an Aerostat System 782
16.3.2 Types of Aerostat Systems 782
16.3.3 Applications 783
16.4 Millimetre Wave Satellite Communication 784
16.4.1 Millimetre Wave Band 784
16.4.2 Advantages 785
16.4.3 Propagation Considerations 787
16.4.4 Applications 788
16.4.5 Millimetre Wave Satellite Missions 789
16.5 Space Stations 793
16.5.1 Importance of Space Stations 794
16.5.2 Space Stations of the Past 794
16.5.3 Currently Operational Systems 797
16.5.4 Planned Space Stations 799
16.5.5 Emerging Space Station Concepts 801
Further Readings 803
Glossary 804
Index 807
