Handbook of Satellite Applications

This chapter introduces what is meant by the term “applications satellite” and addresses why it makes sense to address the four main space applications in a consolidated reference work. This handbook employs a multidisciplinary approach and thus includes technical, operational, economic, regulatory, and market perspectives. These are all key areas wherein applications satellites share a great deal in common. This commonality can be seen in terms of spacecraft systems engineering, in terms of launch services, in terms of systems economics, and even in terms of past, present, and future market development.This is not to suggest that there are not important technical and operational differences with regard to the four prime areas of satellite applications, namely, communications satellites, remote sensing satellites, global navigation satellites, and meteorological satellites. Such differences are addressed in separate sections of the handbook.Yet in many ways there are strong similarities. Technological advances that come from one type of applications satellite can and often are applied to other services as well. The evolution of three-axis body-stabilized spacecraft, the development of improved designs for solar arrays and battery power systems, improved launch capabilities, and the development of user terminal equipment that employs application-specific integrated circuits (ASIC) are just some of the ways the applications satellites involve common technologies and often in a quite parallel manner.All four types of applications satellites provide key and ever-important services to humankind. Around the world, people’s lives, their livelihood, and sometimes their very well-being and survival are now closely tied to applications satellites. Clearly the design and engineering of the spacecraft buses for these various applications satellite services as well as the launch vehicles that boost these satellites into orbit are very closely akin. It is hoped that this integrated reference document can serve as an important source of information that addresses all aspects of application satellites from A to Z. This handbook thus seeks to address all aspects of the field in a totally comprehensive basis.This Handbook of Satellie Applications thus covers spacecraft and payload design and engineering, satellite operations, the history of the various types of satellites, the markets, and their development – past, present, and future, as well as the economics and regulation of applications satellites, and key future trends.

In the 50 years that followed the first satellite launches of the late 1950s and early 1960s, the diversity of satellite services has expanded enormously. Today, there are direct broadcast radio and television services to the home and even to mobile receivers. There are mobile satellite services to airplanes, ships at sea, and even hand-held transceivers. There are so-called fixed satellite services to earth stations of various sizes down to so-called very small antenna terminals (VSATs), microterminals, and even ultra small aperture terminals that can be located on desktops. There are data relay satellites and business to business satellite systems. The age of the Internet and data networking has certainly served to add to the diversity of satellite services. Technology innovation has also led to the growth and development of satellite communications services. Lower cost launch arrangements and development of earth station technology and particularly application specific integrated circuits have been key to driving down the cost and size of ground antennas and transceivers. The development of three axis body stabilized spacecraft, better solar cells and batteries, and more effective on-board antenna systems and on-board switching among multi-beam antennas have also furthered the cause. Finally, the development of not only bigger and better satellites but the evolution of satellite systems design and network architecture that allowed networks to be deployed in different types of orbits and network constellations has been part of this on-going evolution.The latest iterations of satellite design have led to almost opposite extremes. On one hand there are large, sophisticated multi-ton satellites, known as high throughput satellites, deployed in traditional geosynchronous orbit locations. On the other hand, there are also small but capable satellites in low to medium earth orbit constellations. These new satellite networks are being designed with more and more mass-produced satellites – up to a thousand or more in a single system – to increase network capacity by means of deploying more and more satellites in lower orbit.This chapter provides a general introduction to all of these changes and an overview to the entire field. Changes to satellite communication networks over the past half century have come not only in services and technology but also in regulation, standards, frequency allocations, economics, as well as the global reach and impact of satellites on the entire scope of human society.

The history of satellite communications is a rich one that began centuries ago with the efforts to interpret the meaning of the “wandering planets” among the stars and to understand the structure of the cosmos. Early scientists such as Sir Isaac Newton and writers of speculative fiction both contemplated the idea that humans might one day launch artificial satellites into orbit for practical purposes. This chapter provides a brief overview of that rich international history up through the early days of global satellite operations. This history continues to provide a narrative concerning the different types of satellites that have evolved to offer various kinds of services and the development of competitive satellite networks that are at the core of the communications satellite industry today. A brief history of military satellite systems and the “dual use” of commercial satellite systems to support defense-related communications needs is also addressed.

This chapter examines the ever-increasing number of services and applications that are now provided by the commercial satellite industry. It explains basic types of satellite services as defined by the ITU for the purpose of radio frequency allocations – particularly the broadcast satellite service (BSS), fixed satellite service (FSS), and mobile satellite service (MSS). This section further explains that regulatory, standards, and policy actions by various international and regional organizations, plus commercial competition also leads to the development of different terms to describe new and emerging satellite services. Key to the development of satellite services and applications within the global telecommunications market is not only the development of new satellite technology but also the competition between satellites and terrestrial wireless, coax, and fiber-optic networks. Satellites and terrestrial systems, despite being competitive, are nevertheless often complementary because they have particular strengths and weaknesses that do complement each other. Further, these systems are also used to restore each other against outages – particularly during natural disasters. Satellites have evolved in their offerings for nearly 50 years and will continue to do so in the future including services to interplanetary distances and perhaps beyond.

One of the key elements of a communications satellite service is the ability to launch satellites into precisely defined orbits and to maintain them in the desired orbit throughout the lifetime of the satellite. The system control and oversight of satellite orbits both require not only the technical ability to launch and maintain the orbit, but the ability to attain the proper legal authority, at the national and international level, to transmit and/or receive radio signals from these orbits. This regulatory process means a number of specific steps associated with registering for the allocated frequencies from the International Telecommunication Union (ITU)through a national governmental administration, obtaining assignments of those frequencies in the required orbits in accord with national licensing procedures, and coordination of the use of the specific frequencies through intersystem coordination procedures.There are a wide range of different orbits that are currently used in communication satellite services although the most common are geosynchronous Earth orbits (GEO), medium Earth orbits (MEO), and low Earth orbits (LEO). This chapter explains the various orbits that can be used and the advantages and disadvantages of each of the orbits most often employed for satellite communications. This analysis indicates some of the primary “trade-offs” that are used by satellite system engineers in seeking to optimize a satellite systems performance both in its design and subsequently over its operational lifetime. The activities involved in selecting an orbit; designing and achieving an operational satellite network; and optimizing its technical, operational, and financial performance over the systems lifetime involve a wide range of issues. These start with selecting a desired orbital framework, obtaining authorization for orbital access (including the registering and precoordination of the satellite and its orbit with other systems), launch, deployment and test, systems operation, and end-of-life disposal of a satellite from its orbit.

The history of fixed satellite services (FSS) systems, in terms of technological and institutional development, has been previously provided in chapter “History of Satellite Communications” of this handbook to a very large extent. Thus, this chapter addresses the market trends related to FSS systems and also discusses how a variety of new types of satellite services has evolved out of the initial FSS networks over time.The market dynamics and trends of FSS systems are particularly addressed in terms of four main factors: (1) the competitive impact of high-efficiency fiber-optic terrestrial and submarine cable communications networks; (2) the conversion of FSS systems from analogue to digital services that allowed FSS systems to be more cost-efficient and use spectrum more efficiently as well as migrate to spectrum in higher bands more effectively; (3) the move of FSS systems toward deployment of smaller and lower cost ground systems (variously called VSATs, VSAAs, USATs, and microterminals) that allowed services to migrate closer to the “edge” of telecommunication user networks (i.e., satellite services directly to end user facilities); and (4) a shift in regulatory policy that allows FSS systems to compete directly for services that has generally served to reduce cost and spur innovations in services and applications.These four trends have combined to contribute to what has been previously described in chapter “History of Satellite Communications” as “technology inversion.” This “technology inversion” has thus seen FSS systems in space become larger, more complex, longer-lived, and more powerful as ground systems have become more user-friendly, lower in cost, and are designed to interface directly with users at localized office facilities or even small office/home office (SoHo) VSATs or microterminals. These technological, regulatory, and market-based trends have shaped the FSS networks and related market dynamics. All four of these trends have dramatically reshaped the nature of FSS services for both commercial markets and defense-related satellite networks around the world.The historical trend in FSS markets has been the initial development of global networks since global connectivity was the highest value market and the most underserved by terrestrial telecommunications networks available in the 1960s. Over time, satellite technology matured and the economical viability of regional and domestic satellite systems evolved in the years that followed. Today there are some 300 FSS satellites, essentially all in GEO orbit where these systems provide a complex combination of global, regional, and domestic satellite services. Although broadcast satellite services have outstripped FSS in terms of market value and sales, the FSS is still a very large and growing multibillion dollar industry.

The advent of satellite communications brought a new era to the TV industry. In the early years, however, the use of satellites was quite costly and limited by the modest capacity of the first commercial communications satellites. However, the evolution of satellite technology and the development of satellite aggregators, such as Brightstar, Wold Communications, Bonneville, IDB, Keystone, and Globecast, led to a sharp reduction in the cost of satellite television. The development of full-time, annualized satellite transponder charges – as opposed to per-minute fees – was also critical to the development of much lower satellite television fees.The evolution of digital television services was another important breakthrough. Instead of the one or two television channels per transponder with analog systems, it became possible to derive up to 18 channels per transponder. Digital transmission speeded up the evolution of domestic television satellite systems and played a key role in the growth of direct-to-home satellite broadcasting.The development of satellite-based video systems was not seamless and encountered periods of major market difficulties. One of the most prominent market development issues was the failure of early direct broadcast satellite systems (or BSS in the terminology of the ITU).However, DBS (or BSS) satellite markets are now well established in international, regional, and domestic markets. They are not only highly successful but represent by far the largest single satellite market in terms of revenues. Most recently, there has been a rapid growth of high-definition television (HDTV) service via satellite.These satellite services compete with coaxial cable and fiber-optic-based CATV systems.The economics of satellite television are quite different from terrestrial networks because once a direct broadcast satellite system is launched and operational there is very little incremental cost beyond the consumer terminal needed to receive service. The advent of new digital interface standards known as digital video broadcast with return channel service (DVB-RCS) and Digital Over Cable Service Interface Standard (DOCSIS) have allowed the rapid development of digital television over satellite and cable systems. DOCSIS is now widely used for both satellite and cable television systems. These digital standards, together with high-power fixed satellite systems and broadcast satellite systems – that by definition have high power – allow not only the distribution of a large number of video channels to consumers but also low-cost distribution of high-speed digital data service to both home consumers and businesses. These digital satellite video systems can be – and indeed are – used to provide broader band digital services to the “edge” of digital networks at low cost. Thus DBS and higher powered FSS satellite systems are now being used to provide commercial broadband data services to business as well as broader band digital services to remotely located consumers.

The first commercial mobile satellite service (MSS) system was implemented to meet the urgent needs of the maritime community for improved communications. As enhancements occurred in satellite technology and circuit integration resulted in availability of low-cost digital signal processors, MSS systems were deployed to support smaller earth terminals for aeronautical and land mobile applications. The growth of the Internet and improved wireless access has led existing MSS system operators to introduce new capabilities that include improved data and multimedia access. This transformation in the MSS markets has offered several technology challenges, particularly with higher-power spot beam satellite deployment designed to operate with low-cost personal user terminals.This chapter addresses the history and evolution of the technology starting with the Marisat system in the 1970s. This historical review covers both the space technology and user terminals and the market characteristics of the various types of MSS systems. Some systems have not been successful in the market and have not done well financially for reasons associated with market demand, cost, and reliability of service and technology. Currently, there is a convergence of terrestrial wireless services with mobile satellite services. One approach has been to offer dual frequency band handsets that switch from one band to the other depending upon whether the user is within the terrestrial system’s coverage. The other approach is for the MSS system operator to support both satellite and terrestrial coverage in the MSS frequency bands to achieve seamless operation for the user. The demand for very high data rates for better Internet access had also led to a convergence of MSS and FSS system capabilities, where many of the capabilities of an MSS are being offered by FSS system operators and vice versa. Fortunately, continuing innovations are assuring mobile users the availability of reliable communications from anywhere in the world.

Commercial telecommunications satellite systems that provide fixed (FSS), mobile (MSS), or broadcasting (BSS) satellite services provide essentially “real-time” communications to satisfy the market needs of their commercial customers or support military communications requirements. The service is not precisely simultaneous in that there is close to a quarter second delay in the case of a satellite relay that travels from Earth to a geosynchronous satellite and then back to Earth. For normal commercial satellite services to support voice, data links, radio or audio channels, videoconferencing, or television service, the satellite link is provided on as close to a real-time basis as is technically possible.There are, however, a variety of communications satellite services that are variously known as store and forward, business-to-business (B2B) relay, machine to machine (M2M), or data relay satellites. These types of “data relay” satellite services are typically not as instantaneous as is the case with the big three services – namely, fixed, mobile, and broadcasting. This type of service is usually machine-to-machine data relays, and thus some delay in the transmission is usually not important.Thus, what makes these types of satellite offering different is that there can be an acceptable time delay in the satellite data relay service. This delay, depending on the nature of the satellite service, can range from less than a second, to minutes, and to even hours. These various types of data relay satellite services will be addressed in this chapter. There is actually a wide variety of these satellite services that can also operate in different frequency bands. These diverse services and satellite types are designed to meet rather different types of communications and networking services. Some data relay satellites are very simple, small, and low-cost satellites that support amateur radio or volunteer efforts. Others are much more complex and actually support commercial customers. Yet others are designed for satellite-to-satellite interconnection and can be large, complex, and rather costly satellites.Among these various types of data relay or machine-to-machine (M2M) services are the following: (i) amateur radio relay that is provided via so-called OSCAR satellites in the amateur radio band to allow global AMSAT connectivity and (ii) data networking using small satellites in various types of LEO or MEO orbits, or constellations, to provide non-real-time data relay services, often of a public service nature. Yet, this can also support commercial B2B or M2M services such as the Orbcomm satellite system. This commercial satellite system was designed to provide a minimum gap in connectivity and carry out such functions as near real-time tracking and communications with vehicles and ships and (iii) data relay services from GEO orbit to allow broadband communications with satellites or spacecraft in low or medium Earth orbit – or even UAV surveillance systems. These GEO-based data relay satellites are able to track and connect with lower orbit satellites and thus relay data from such satellites with minimum delay to ground communications centers half way round the world in close to real time. Such types of data relay satellites can be used to connect to spacecraft with passengers on board. These data relay satellites, such as NASA’s Tracking and Data Relay Satellites, were used to support flights during the US Apollo moon program and then with the Space Shuttle. These TDRS allowed NASA to maintain connection to ground control facilities on close to a real-time basis. The different technical aspects of the various types of store-and-forward or data relay satellite systems, the frequencies they utilize, and the various types of services they support are all addressed in this chapter.The common denominator for these diverse types of satellite services is that they are not real time but rather involve some elements of time delay. In the case of the most sophisticated data relay satellites, the connection may involve a delay on the order of a second. In the case of the most basic and low-cost store-and-forward satellite systems, the delay may be a period of several hours from the initial uplink to the ultimate downlink of the data message. Today, new types of store-and-forward data relay satellites can be quite sophisticated and high-cost systems that can handle high data rates. These new type of data relay satellites have progressed a long way forward in terms of data throughput capabilities and can be more than a thousand times more capable than the first types of simple data relay satellites of the 1960s and 1970s. These much more broadband and sophisticated data relay satellites also operate in many higher frequency bands.

Rapid growth in demand for broadband Internet services has brought new challenges to the satellite industry. Satellite networks must have an incredible amount of bandwidth to deliver high-speed broadband service to large population of subscribers. Ku-band transponder satellites, which comprise a large fraction of the current worldwide fleet, are typically limited to 1-2 Gbps of total capacity. Ku-band satellites do not have the scale and bandwidth economics required to provide a compelling broadband service. To satisfy the demand for Internet bandwidth, large broadband satellites need 100 s of Gbps of capacity. The satellite industry has responded to this challenge with new payload designs and new satellite system architectures, advancing into higher-frequency bands and incorporating aggressive frequency reuse, advanced waveforms, adaptive coding and modulation, and other techniques. Broadband satellites approaching 150 Gbps of capacity are now in orbit. Satellites with up to 350 Gbps of capacity are being manufactured and will be launched in the 2016–2017 timeframe. The 1000 Gbps barrier will be exceeded in 2020 with the launch of recently announced third-generation broadband satellites from ViaSat.

One of the most significant recent developments in satellite communications has been the sudden resurgence of large-scale constellation satellite programs to provide broadband services. This has occurred some 20 years after the several unsuccessful attempts to deploy such huge constellations like Teledesic in the USA and Skybridge in Europe. These were never deployed for several reasons that included financing and the bursting of the Internet bubble at the end of last millennium.Of course, other telecommunication constellation programs have been deployed since that time (Globalstar 1st and 2nd generation and the Iridium and soon Iridium Next for instance). These systems, however, were designed to address narrower band services in low band frequencies (L and S-band) for mobile telephony and low-medium rate data.These new types of constellations that are currently either recently operational or under design and development are intended to mainly provide broadband Internet-optimized services with the ability to offer low latency performances compared to geostationary satellite alternatives. These new systems, and in particular the O3b and OneWeb networks, both headquartered in the tax haven Jersey Island, UK, as well as the Leosat initiative, from a Delaware registered company, have been described as “disruptive,” “game-changing,” and “innovative” in their architecture (P. de Selding, “Never Mind the Unconnected Masses: Leosats Broadband Constellation is Strictly Business”, Space News, Nov. 20, http://spacenews.com/nevermind-the-unconnected-masses-leosats-broadband-constellation-is-strictly-business/, 2015).One remarkable aspect is that each one represents very different and specific approaches to addressing broadband applications by satellite. Some are in Low Earth Orbits (LEO) at about 1000–1500 km altitude while O3b is flying much higher in Medium Earth Orbits (MEO) at about 8000 km altitude. O3b is an equatorial MEO system of 12 full-sized satellites. Others are intended to represent a network of some 100 satellites of 700–1300 kg mass while yet others are requiring several hundred spacecraft of 175–200 kg mass. Some are envisioned to provide “local” services connecting a gateway with users in visibility of a sole spacecraft scale (Proposed Leo Sat Constellation, Space News, March, 2015 http://spacenews.com/proposed-leosat-constellation-aimed-at-top-3000/Last. Accessed 9 Dec 2015).Other systems are designed with a more interconnected architecture for connecting users to a gateway or another user that can be located far away in an another continent thanks to inter-satellite links.However, each concept in its own way is raising a number of regulatory and technical challenges.This trend to deploy new broadband constellations for fixed and mobile satellite services started with the deployment of the medium earth orbit O3b constellation in 2013 and 2014, and now OneWeb has selected in mid-2015 Airbus Defence and Space as a joint venture partner to invest and manufacture some 900 small satellites (i.e., operational plus spares) to be deployed starting in 2018. There may be other companies that follow suit to deploy similar so-called mega-constellation systems, but currently OneWeb is the only such LEO constellation system under a development contract to manufacture and launch such a large-scale network. Another possible system has started design and engineering phases such as Arlington, Virginia-based LeoSat (although officially headquartered in Delaware). This system is exploring an 80 satellite that might be expanded to about a 110 satellite constellation. This project involves Thales Alenia Space. Then there is the announced effort whereby Singapore Space Intelligent IoTS Pte. Ltd. (SSII) is partnering with German satellite maker OHB System to develop the world’s first Asia-based low Earth orbit Internet constellation (Singapore Space Intelligent IoTS Pte. Ltd. http://www.ssii.sg/Last. Accessed 8 Mar 2016).Finally, there have been reports of a Space-X backed system that might deploy as many as 4000 satellites in a massive mega-LEO system.These systems are, however, not yet contracted to manufacturing and thus are not addressed here in details. The Space X system would presumably like OneWeb involve quite a huge number of small satellites and be aimed at underserved developing countries’ markets among other more mature markets. The LeoSat system in contrast would involve much larger and capable satellites with more than 2 kW of power and would be aimed at meeting the special needs of the largest corporations in the world (Propose LeoSat).The implications of such large-scale constellations of small satellite are manifold. These new type satellite networks would seem to revolutionizing the cost of manufacturing and launching spacecraft, concerns about radio frequency allotments and protection from interference, orbital debris build-up and removal, collision avoidance, management of liability concerns, and more. What is clear is that the deployment of those satellite constellations in low earth orbits will provide a satellite network that is quite different in many ways when compared to GEO satellites. The LEO satellites would typically be some 30 times closer to the Earth’s surface than GEO satellites with about 60 times less transmission delay for a round trip. Clearly such a network can accommodate latency-sensitive applications in Internet data transmissions (i.e., TCP/IP protocols) with greater efficiency and support voice conversation services with greater facility. On the other hand, their closer vicinity with the earth’s surface restricts their coverage reach, and this requires many more satellites for a continuous earth coverage.This new trend to deploy satellite constellations for broadband satellite services is occurring in close parallel with the development and deployment of very high throughput satellites (VHTS) in geostationary orbit that provide much greater capacities at lower costs. Clearly these parallel and potential “disruptive” trends to deploy even more capacitive HTS and low earth orbit constellations could serve to drive down costs and make available new digital services to consumers around the world at much lesser costs. We can even expect in a midterm the integration of both complementary solutions, the very high capacitive geostationary HTS systems providing a much higher data rate per user together with mega-constellation services offering low latency data flow and a world coverage including the poles. The involvement of well-known international satellite operators of geostationary fleet such as Intelsat that is involved in the OneWeb project or SES in the O3B is probably a revealing clue.This chapter describes the various systems that have been implemented or now in production to be deployed in the coming years – especially O3b and OneWeb. This chapter provides some of the basic technical and operational characteristics of these new systems. It also addresses the various types of new services that are being offered or planned by these types of networks.It was thought in the 1990s, a mega-LEO satellite system for broadband fixed satellite services similar to OneWeb might deployed. This network, which was named Teledesic and financially backed by Bill Gates, Greg McCaw, and venture capitalist Ed Tuck, was proposed along with about 15 other Ka-band satellite networks. The Teledesic system and the other proposed Ka-band systems were never deployed – except for the Wild Blue Geo satellite network (renamed the Ka-band satellite system) and which was delayed over a decade in its actual launch and deployment. Today, some 20 years later, the viability of such large-scale lower earth orbit satellite systems now seem to be economically feasible again.Thus, the first generation of O3b has been designed, manufactured, and successfully deployed, and rapid progress is being made to design, manufacture, and launch OneWeb in a not so distant future. The advent of 3D printing, advanced manufacturing techniques taking benefits of more automated processes for large-scale production and testing, more extensive use of commercial off-the-shelf (COTS) components, and new commercial systems to launch small satellites at low cost have combined in a positive fashion to greatly reduce the cost of building and launching such satellites.New satellite networks, born out of Silicon Valley, such as the Skybox constellation for remote sensing, now acquired by Google, have served to unveil a whole new pattern of commercial satellite business. “Disruptive” technologies and new satellite system architectures are thus the hot trend of the day driven by so-called New Space commercial ventures.

This chapter provides information concerning the use by governments of military and commercial satellites systems for strategic and defense purposes. It discusses dedicated communications satellite systems designed for particular uses and the so-called dual use of commercial systems to support military and strategic purposes. It explains various pathways that can be followed by governments to obtain communications satellite services to support military uses. These paths include: (1) dedicated satellites, (2) hybrid satellites (both military and commercial payloads on a single satellite), (3) shared satellite facilities via intergovernmental agreements, (4) guaranteed long-term leases, (5) ad hoc leases of capacity on demand, and (6) a long-term partnership between a government and a commercial partner as is the case with the Skynet 5 program in the United Kingdom.In this chapter the authors will also examine how various countries obtain their national satcom, how and why commercial capacity has become, and will continue to be, a significant part of national satcom capabilities. It will examine the present and future contracting approaches and procedures used in various countries but primarily in the United States and other NATO countries.Finally, there will be a discussion of the issues involved when nations decide between purchasing nationally owned satellites and leasing capacity commercially. In this regard, it is noteworthy that in many cases the major investments in new technology for satellite defense communications systems are now more often coming in the commercial communications world. Governments are more and more changing their procurement models to take advantage of commercial procurements or long-term leases. This allows military communications units to spend their financial resources more strategically on any small adjustments to make their satellite acquisitions more military specific. Technology is typically moving too fast for a “normal” 5-year military R&D program followed by procurement cycles to be at the cutting edge of the latest technologies in today’s world.

The economics and financing of satellite communications is a very large and complex topic. It ranges from normal business planning, analysis, and investment financing, to issues of government policy, dual-use technologies, and national security and defense. Commercial satellite systems represent a special case of economic analysis since such systems are heavily dependent on a government market that is focused on political considerations of budgeting and regulation. Today, satellite telecommunications systems are critical to almost all nations of the world, and they are especially important in approximately 60 nations that have domestic launch and/or satellite operations capabilities. This chapter will specifically focus on four topics: (1) a summary of the economic characteristics of the industry and a review of major trends in the industry, (2) a summary of the elements of a business plan for satellite telecommunications, (3) an analysis of issues in the manufacturing productivity for satellites and an analysis of commercial satellite manufacturing compared to government satellites, and (4) a brief discussion of future cost considerations including the increasing risk of space sustainability, insurance, and rules concerning disposal of satellites after their useful lifetime.

Radio frequencies allow information to be transmitted over large distances by radio waves. The essential element to high-quality satellite communications is the assignment of radio-frequency spectrum to various types of services. Only a limited amount of such spectra is assigned to Earth-space radio links, and thus the available bandwidth must be used with a high degree of efficiency. There are many technical elements associated with the efficient use of RF spectra for satellite communications and navigation, and these elements are addressed in some detail in this chapter.The basic properties of electromagnetic waves are first discussed, together with an overview of the basic electromagnetic phenomena such as reflection, refraction, polarization, diffraction, and absorption useful to define how radio waves travel in free space and in atmosphere. The basic parameters used to characterize the antennas responsible for generating and receiving these waves are introduced.A survey of the propagation impairments (gas and rain attenuation, scintillation, etc.) due to the nonionized lower layers of the atmosphere from Ku- to Ka- and V-bands is presented. On the other hand, radio waves of Global Navigation Satellite Systems (GNSS) interact with the free electrons of the upper atmosphere ionized layers on their path to the receiver, changing their speed and direction of travel.

Ready access to radio frequencies with limited interference and appropriate orbital positions are indispensable and highly valuable tools for all satellite communications. However, radio frequencies are limited, natural, and international resources. Furthermore, the global demand for radio spectrum has been increasing exponentially. Acting primarily through the International Telecommunication Union (ITU), the international community has developed a very complex regulatory regime that provides detailed rules and processes that govern the international allocation and allotment of radio frequencies and orbital positions. This chapter briefly describes those regulatory processes as well as the manner in which they are created as part of the functioning of the ITU. This chapter thus provides the basics of ITU procedures for frequency allocations. The immediately following chapter provides the status of the ITU World Radio Conference held in Geneva, Switzerland in the fall of 2015 and the many key new outcomes that occurred at this conference with regard to satellite communications.

The International Telecommunication Union (ITU) convenes World Radiocommunication Conferences (WRC) for the purpose of concluding a treaty on emergent issues related to the operation of radio-based systems. This effort includes allocation of radiofrequency spectrum and procedures for accessing the orbit for satellites and results in amendments to the international Radio Regulations. The 2015 World Radiocommunication Conference (WRC-15) took place on November 2–27 in Geneva, Switzerland, with an agenda that included some forty topics. One of the key themes of WRC-15 was competition to access scarce radio spectrum resources, while also finding a way to enable introduction of innovative new services and technologies.WRC-15 featured the latest campaign in the ongoing confrontation between the mobile telephony/broadband industry and the satellite industry over spectrum resources. The objective was to grant access to premium regional and global spectrum allocations to enable extension of desired terrestrial services without harming established satellite services providing lifeline connectivity and other important connections. However, this spectrum duel did not end up being the defining issue of WRC-15 as there were so many fractious issues that deeply divided the proceedings. But, in the end, the conference found a way forward on every issue and approved plans for its next proceedings in 2019 and 2023.As described in this chapter, the satellite industry, led by major industry players and fueled by aspiring newcomers, not only defended its essential spectrum resources but accomplished key regulatory improvements to pave the way for future innovation – including new spectrum access, lifting constraints on mobile applications by satellite, and preparing the way for newly announced non-geostationary satellite systems. WRC-15 was thus a banner conference for the satellite industry.

The last 50 years of satellite communications has followed a consistent trend to produce networks that can provide higher and higher rates of throughputs at lesser cost. Closely linked to this trend has been a parallel effort to seek more efficient use of the allocated frequencies. The first satellite systems were power limited, but as satellite engineers designed more powerful spacecraft, the challenge has been more and more to find ways to use frequencies more efficiently. In short, in a digital world, the objective has become to send more bits of information per available Hz of radio frequency. This has been primarily accomplished by using greater complexity in the coding and multiplexing systems. This has also been achieved by polarization isolation and higher-gain antennas (and thus narrower spot beams) that enable geographic isolation of the transmitted beams. If these narrow beams are spread sufficiently apart, this reduces interference and the radio frequencies can be reused over and over again. This process also minimizes the effective path loss of irradiated power by concentrating the beam to a tighter area.This 50 years of satellite progress can be summarized by the ever-increasing power levels, frequency allocations, and system complexity to increases throughput efficiency. This “complexity” has allowed more throughput of information via the spectrum that is available. This is now typically measured in the metric of “digital bits” per hertz.The fixed-satellite services (FSS), the mobile satellite services (MSS), and the broadcast satellite services (BSS) each in their own ways have applied this process to exploit the available frequency bands progressively over time. The lower-frequency bands have been used up first to meet initial demand in the earliest years. This is simply because these bands are easier to use. This is primarily because there is less rain attenuation in the lower frequencies and the radio transmission equipment and antennas are easier to design, manufacture, and use. In the case of the fixed-satellite services, the C band (at 6 and 4 GHz) was used first. Then the Ku bands (at 14 and 12 GHz) were utilized next and then they became largely saturated. Currently the greatest amount of expansion is in the so-called Ka band (this is the 30 and 20 GHz bands) that requires high power and encoding complexity to overcome rain attenuation issues. Despite the efficiency gains that come with the use of higher power, high-gain antennas, and coding complexity the current commercial satellite frequencies (in C, Ku, and Ka band) wiil eventually saturate. This is because of ever increasing demand for broadband video and data services and expanding access to users around the world. Further the satellite allocation for C-band was reduced as a fully protected service.The next frontier thus seems to be the so-called Q/V bands of 47.2–50.2 GHz and 37.5–40.5 GHz, and beyond that, the expansion will be to even higher frequencies such as the W band, the terahertz (THz) band, and even the light-wave frequencies. The use of such high frequencies with ever-shrinking wavelengths is a challenge for satellite service, because atmospheric conditions make the use of such spectrum very difficult indeed. The one area where satellites have an advantage would be for transmissions that occur above the Earth’s atmosphere. The use of light waves or laser communications for intersatellite links (ISLs) or cross-links to connect satellites in orbit is not only possible but is starting to be used for this purpose. Laser cross-links for low Earth orbit constellations is easiest, but this is also possible for medium Earth orbit constellations or even GEO satellites.There are many challenges represented by the higher radio frequency (RF) bands. These challenges include building radio equipment that can operate effectively and efficiently at these exceeding challenging frequencies. The great challenge is to utilize these microscopic wavelengths and to cope with the atmospheric interference that tends to block the signals at the Q/V and W bands and higher. Here it is a matter of not only rain scatter of the signal but also the oxygen absorption, scintillation, and other problems that weaken, distort, or otherwise interfere with satellite signals in these millimeter wave and even the THz frequency ranges. Light-wave transmissions from ground to space and back constitute an even greater difficulty.Nevertheless, satellite communications systems of the future can be expected to operate in these challenging frequencies. In order to do so, however, new modulation and multiplexing equipment, signal regeneration, coding systems, antennas, and power systems will likely all be needed to deliver secure and reliable service in the future. In the meantime, better coding processes, higher power transmission, and improved and higher-gain antenna can extend and expand the efficiency of usage of the lower-frequency bands. It is possible that instead of such a heavy reliance on satellites in the GEO orbits, lower orbit satellite constellations and high-altitude platforms (HAPS) can also be deployed in the Ku band and Ka band to provide additional throughput capabilities. A third factor to consider in assessing future demand is the additional build-out of high-capacity fiber-optic networks. These extremely broadband systems could also serve to reduce the demand for future satellite services. Nevertheless, the demand for mobile, rural, and remote services plus broadcasting and multi-casting services should still sustain satellite growth for some time to come.This chapter, in particular, focuses on the technical, operational, and practical issues associated with the development and future deployment of future satellites in the Q/V and W bands. It also briefly discusses the even higher terahertz frequencies and light-wave or laser transmission.

Satellite communications makes use of radiofrequency links. Particular frequencies are allocated for satellite communications through international regulatory registration and coordination processes which prevents interference between systems. In typical operation, a satellite’s transponder receives an uplinked signal from Earth, changes its frequency slightly to avoid self-interference, and retransmits it on a downlink to Earth. Antennas provide gain by focusing the transmitted energy. Path loss describes a natural spreading out of the transmitted wave front as it travels through space. A link budget is an accounting of gains and losses throughout a system that is used as a design tool to provide sufficient power (or gain) to allow a satellite connection to be established. The link margin is the excess amount of received signal power above what is required. Shannon’s law implies that there are trade-offs possible in a communications system design between power, bandwidth, and complexity.

This chapter addresses the principles involved in three key areas in satellite communications, namely, modulation (and demodulation), forward error coding, and multiple access approaches or techniques. It focuses on features and technical approaches utilized in modern-day digital satellite communications systems. Since analog approaches or techniques are today seldom used in operating satellite networks, they are not addressed in detail. Nevertheless, several references are given concerning such analog techniques should there be a historical interest in these subjects. The materials provided in this chapter are aimed at giving an appreciation of the issues involved and the performance achievable in practice. For more detailed mathematical treatments, an extensive bibliography is also provided.

This chapter explains the technology that makes onboard processing (OBP) function as well as explores the new and important applications that communication payloads, based on onboard processing techniques, can effectively support. Further, it assesses the pros and cons associated with employing this technology in terms of performance, complexity, reliability, and cost. Satellite systems providing fixed and mobile services are evolving from bent-pipe payloads to more and more enhanced satellites with more and more capabilities and “intelligence.” Thus one has seen the evolution of satellite capabilities to be able to achieve more and more functionally in space. We started with the so-called nonintelligent or bent-pipe satellites and then moved quickly to more flexible multi-points-type satellite services. Next, there was the transition to more enhanced satellites with onboard switching, and then most recently there have been design innovations to bring true “intelligence to space.” This has been seen in the move toward highly capable satellites with increasingly “intelligent forms” of onboard processing (OBP).This evolution involves moving from more efficient beam switching to actual processing of signals to enhance signal and remove attenuation affecting the uplink and thus partially overcome rain attenuation. The addition of so-called intelligent functions to the satellite that were once found only in terrestrial signaling and switching systems allows satellites to become more efficient and versatile.In particular, this transition will allow the design and deployment of:Multibeam RF-IF switched transponder satellites (i.e., the ability to provide effective “beam switching” among satellite beams). This allows satellites to provide Physical Transport Layer Network Services that were once restricted to advanced terrestrial networks.And eventually there will be an evolution to advanced packet switched (“Data Switched” asynchronous transmit mode (ATM or ATM-like services). This will allow onboard processed multibeam satellite systems that provide specific and an increased array of network-level services.

The most critical component of a communication satellite is its antenna system. The purpose of this chapter is to show how the antenna works by describing the basic concepts related to satellite antenna pattern, side lobe, gain, and polarization so that satellite antenna systems are designed and engineered to meet specific requirements. First, the fundamental parameters such as antenna pattern, beamwidth, radiation power, gain, and polarization are introduced. Second, basic antenna such as linear wire antenna, horn antenna, reflector antenna, and microstrip antenna is described. Third, array antenna for scanning and hopping beams is described for its function, gain, and phased array. In the fourth, multibeam antenna is described in terms of its function and type. Finally, an antenna for optical communications system is introduced briefly.

In this chapter, the objective is to discuss the practical implementation of various types of satellite antenna designs over time and to indicate the current state of the art and future trends to develop even higher gain satellite antennas with greater efficiencies in terms of frequency reuse or higher capacity FSS or MSS type satellite systems. Although there continue to be smaller satellites that are launched for communications purposes, the antenna designs utilize the same technologies and concepts that are employed in larger scale satellites.The evolution of antennas for satellite communications has generally conformed to the following historical pattern:Low gain omni- and squinted-beam antennasIncreased gain types of satellite antennas (horn type and helix antennas)Parabolic reflectors (including multibeam antennas with multiple feed systems)Deployable antennas (particularly for achieving more highly focused beams and support much high-gain multibeam antennasPhased array feed and phased array antennasScanning and hopping beamsOptical communications systems (initially for intersatellite links and interplanetary communications, but this type of technology might possibly be used for Earth to space systems in the future as well).Examples of many of these types of satellite antennas will be presented in the following chapter. But first, the factors that have led engineers to design improved and higher performance antennas will be discussed and examined.

This chapter reviews the design and operation of user antennas for satellite communications – for fixed, mobile, and broadcast services. This review includes simple dipole antennas and progresses to Yagi-Uda antennas and then on to high-gain parabolic reflector antennas that are the most commonly used in satellite communication systems. The trade-off between antenna gain and beamwidth is explored in detail. The key differences in the design process for very small aperture terminals (VSATs) and large earth stations are explained. The influence of blockage on whether to choose offset-fed antennas over on-axis fed antennas is seen to be key. This is particularly true for small aperture antennas with diameters of less than 100 wavelengths. Frequency reuse through dual-polarization operation is presented, with the different system advantages of dual-linear and dual-circular operation set out. The impact of the choice of modulation on the power margins required for a given bit error rate (BER) is seen to be significant. Noise temperature contributions from the atmosphere, from the ground, and particularly from lossy-feed runs that reduce antenna performance are explored. Reducing the feed losses is key to the design of very large earth station antennas. The difference in the impact of noise temperature on the uplink and the downlink is explained, and the differences between antenna design and performance with regard to fixed-satellite service, mobile satellite service, and broadcast satellite services are noted. Finally, some additional aspects of earth station designs that are affected by the environment, both meteorological and interference, are discussed.

This chapter discusses the challenges of integrating space and terrestrial systems as well as some of the unique solutions and approaches to solving those challenges. While the first satellite systems were stand-alone and akin to a private network in today’s terminology, virtually all current satellite systems are interconnected through some component of the terrestrial infrastructure, e.g., the Internet, PSTN, or private fiber. This chapter presents examples of the current challenges in integrating space and terrestrial systems by considering two satellite system classes which have unique requirements for interconnection and interoperability: the Mobile Satellite Systems (MSS) and the Broadband Satellite Systems for Internet Access.

This chapter focuses on the regulatory, legal, and trade issues related to satellite communications. The chapter first examines the regulatory and legal issues on three levels: the global or international arena, regional regulatory institutions, and national regulatory frameworks. Next, the chapter focuses on a discussion on the role of satellite communications in global trade and will review the regulatory, legal, and trade issues of satellite communications on the global scale. The last part will discuss issues related to the settlement of disputes that may arise from satellite communications, as well as the legal principles of responsibility and liability for any damage caused by satellite communications. Note that this chapter does not deal with the legal and other issues related to the International Telecommunications Union and radio frequencies, which have been dealt with in previous chapters of this book.

Satellite communications technologies have achieved remarkable breakthrough efficiencies and increases in performance in nearly a half century. These developments, however, have occurred in parallel with large gains in performance by other IT and telecommunications systems. Thus, these dramatic gains are not as apparent to the general populace as might have been the case if this explosion in performance had happened in isolation.In many ways today’s satellites are digital processors in the sky and specialized software defines how they perform and defines their communications capabilities. In fact, the innovations in satellite communications as well as the progression in all forms of telecommunications and computer processes have followed similar courses. In short, Moore’s law that predicted a doubling of performance every 18 months has generally held true for all fields involving digital processing, whether it be computing, communications, video games, or even digital entertainment systems. What had been past is thus likely to be prologue. It is reasonable to anticipate continuing gains in terms of overall processing power, digital communications, and “intelligent” space communication systems.In short, there are remarkable new technologies still to be developed in terms of space-based satellite communications systems, more powerful processors, new encoding capabilities, and new user terminal capabilities that can make user systems more mobile, more versatile, more personally responsive, more powerful in terms of performance, and yet lower in cost (J.N. Pelton, Future Trends in Satellite Communication (International Engineering Consortium, Chicago, 2005), pp. 1–19; Also see T. Iida, J.N. Pelton, E. Ashford, Satellite Communications in the 21st Century: Trends and Technologies (American Institute of Aeronautics and Astronautics, Reston), pp. 1–15, 2003).As the world national economies become more global and as all parts of the globe, the oceans, and the atmosphere are exploited by human enterprise, the need for effective wireless interconnection via terrestrial wireless and satellite communications will expand. Further, the increased utilization of space systems to explore outer space – manned and unmanned – will increase the need for improved space communications systems. Clearly foreseeable technologies suggest that several more decades of continuing innovations are now possible. But technology will not be the only source of change for the satellite communications industry. Other drivers of change will include: (a) new service demands in both civilian and defense-related markets; (b) restructuring of commercial satellite organizations through acquisition, merger, and regulatory change; (c) new allocations or reallocation of frequencies and increased frequency interference; (d) convergence between and among the various satellite applications markets – both in terms of technology and structural integration; (e) constraints in orbital configurations; and (f) increased concerns with regard to orbital debris. Further, the growth of human activities in outer space may prove to be significant shapers of new satellite systems in the next 20–30 years (J.N. Pelton, Future Trends in Satellite Communication (International Engineering Consortium, Chicago), pp. 1–19, 2005; T. Iida, J.N. Pelton, E. Ashford, Satellite Communications in the 21st Century: Trends and Technologies (American Institute of Aeronautics and Astronautics, Reston), pp. 1–15, 2003).

The use of space systems to support military activities and enhance defense-related capabilities has increased exponentially since their first application in 1965 with the Initial Defense Satellite Communications System. Although the first major application was for communications services, space-based defense capabilities have now expanded to provide a wide range of other types of services. Today these applications include navigation, targeting, mapping, remote sensing, surveillance and meteorological tracking, and prediction. In short, 50 years of expanded space-based capabilities for military and defense-related services seem destined to be followed by 50 years of even greater capabilities. Thus, there will be expanded competence in terms of new types of space hardware and new applications. Further, entirely new capabilities will be added. These will likely include expanded use of artificial intelligence and increased focus on cybersecurity and space situational awareness, on-orbit servicing, and perhaps even active orbital debris removal.This chapter examines all of these trends and discusses whether some of these trends will relate to improved commercial satellite capabilities, particularly in the context of dual use of commercial networks and hosted payload systems.

The “youngest” of the major satellite applications is the field of satellite navigation. This field of measurement and ranging through the use of satellite positioning systems first started in the context of scientific research. This initial use of satellites was simply for positioning and location. These activities, that were first based on using Doppler frequency shifts as a satellite orbited above, were largely scientific and not strategic. These types of activities included geodetics (i.e., such as the measurement of continental drift over time) or the collection of scientific information and data from atmospheric land- or ocean-based sensors where the specific locations of the sensors were important.The real strides in the development of satellite navigation, however, came when space systems were developed for the specific purpose of precise targeting of missiles and various other types of weapon systems. The Soviet Union/Russian Federation satellite navigation system, known as GLONASS, and the US-based Navstar system – with its Global Positioning Satellite (GPS) network – developed space-based systems that provided unprecedented capabilities to determine locations on the ground or oceans with great accuracy. Early systems such as Argos that relied on Doppler shift technology were only accurate within a precision of hundreds of meters. Today’s advanced satellite navigation systems, however, are accurate for measurements that can be indicated with a precision only a few meters and within centimeters if utilizing reference stations.The fact that GPS and GLONASS satellite signals are freely available in space for all to use has spurred the development of low-cost receivers for much more than strategic or military usage. Today, various types of civilian use of navigational and positioning satellites have become popular on a global basis. The latest development in application-specific integrated circuit (ASIC) chip technology has fueled the growth of applications based on the use of these precise space-based navigational and positioning systems. The availability of these highly capable but increasingly low-cost chips – small enough that they could be included in handsets such as cell phones or included with the electronics available on various types of vehicles (i.e., cars, trucks, buses, trains, airplanes, ships, etc.) – represented a real breakthrough. The development of specialized computer chips to perform satellite navigation calculations has increased the number of users of this technology from a relatively small population of several thousands to tens of millions. In the coming decade, the proliferation of international satellite navigation systems in orbit (i.e., USA, Russian Federation, China, India, Europe, and Japan) plus the continued development of ever lower cost of satellite navigation chips for receivers will continue the popular expansion of these increasingly “easy to use” and versatile systems.Wide and easy access to low-cost consumer receivers for satellite navigation services strongly suggests that this trend of expanded use will continue to surge. Thus, within a decade, use of these devices will increase to the hundreds of millions if not billions of people. Atomic clocks with incredible temporal precision today allow satellite navigation systems to be used by military organizations, governmental geospatial scientists, and scientists to determine locations with great accuracy. But these applications are now just a small fraction of total usage. The deployment of the new international satellite navigational systems and smaller and lower cost ground receivers will support an ever-increasing civilian consumer market for an ever-expanding range of everyday applications. These consumer applications include driving a vehicle to a desired location, safely sailing a boat, going mountain climbing or hiking without getting lost, or simply finding out where you are within a city.The precise time keeping ability of today’s satellite navigation systems also means that these spacecrafts can also serve as a global timekeeper for computers and scientific experiments. The time stamp from a satellite navigation satellite can also be used not only for scientific or regulatory purposes but for other applications such as security and banking systems as well. These satellites are also used to support the synchronization needs of communications satellites. In short, navigation and positioning satellites have also become in many ways the world’s timekeeper (Cesium clocks and global timekeeping, http://www.rfcafe.com/references/general/atomic-clocks.htm. Last accessed 14 Jan 2016).The official US discontinuation of the so-called selective availability feature for the Navstar satellite system has accelerated the use of the GPS network for highly sensitive applications such as assisting in the takeoff and landing of aircraft. The fact that selective availability could be reactivated has nevertheless been one of the concerns and invoked reasons why other countries have now proceeded to develop and launch their own satellite navigation systems. In short, when nations believe that certain space infrastructure represents a strategic asset, there is a strong motivation to deploy such a system rather than depending on other nations to own and operate such networks.Despite the strategic importance attributable to GNSS services, considerable progress has been made to achieve international cooperation compatibility and standardization among the six systems now in operation via the International Committee on GNSS (ICG) that now meets regularly under the auspices of the UN Committee on the Peaceful Uses of Outer Space.

Global navigation satellite systems (GNSS) are part of the most complex modern space systems humankind has created, and therefore their orbits, orbital parameters, and their two main terrestrial mappings are firstly described. Different frames of space-time reference systems are treated as part of such descriptions.Communication systems engineering are important sections to allow for a GNSS precise fix positioning. All signal structures and data streams are treated for a clear understanding permitting the reader to see how ranging is obtained from space.Theoretical and practical error budgets are considered to give the reader a perception of limitations during scientific and/or technical user campaigns or for simple common life enjoyment.

Global Navigation Satellite Systems (GNSS), with their extremely high accuracy, global coverage, all-weather operation, and usefulness at high velocities, are a dual-use technology that are becoming a new global utility that increasingly improve people’s daily lives. GNSS applications are growing, and their quality is improving in such areas as aviation, maritime and land transportation, mapping and surveying, agriculture, power and telecommunication networks, disaster warning and emergency response, and a host of commercial and social applications.At the turn of the millennium, it became apparent that the two Global Navigation Satellite Systems that had existed, the Global Positioning Systems (GPS) of the United States and the Global Navigation Satellite System (GLONASS) of the Russian Federation, would soon be joined by the Galileo system of Europe and the Compass/BeiDou of China, as well as by the regional Quasi-Zenith Satellite System (QZZS) of Japan and the Indian Regional Navigation Satellite System (IRNSS) of India. The emergence of new GNSS and regional augmentations focused attention on the need for the coordination of program plans among current and future operators in order to enhance the utility of GNSS services. It also made clear that the providers of GNSS services should pursue greater compatibility and interoperability among all current and future systems in terms of spectrum, signal structures, time, and geodetic reference standards to the maximum extent possible.Although coordination between the providers of the GNSS was already taking place on a bilateral basis, the desirability of having a forum in which all GNSS providers participated became an attractive idea. Such a forum would allow discussion and coordination on issues of common interest such as protection of the radio navigation spectrum from disruption and interference, global compatibility, and interoperability of space-based position, navigation, and timing services (PNT) that could be used separately or together without interfering with each other. After 1999, and following several years of discussing terms of reference, objectives, and work plan, the International Committee on GNSS (ICG) became such a forum.

Global Navigation Satellite System (GNSSs) is the standard generic term for satellite navigation systems that provide autonomous geospatial positioning with global coverage. GNSS allows small electronic receivers to determine their location (longitude, latitude, and altitude) to within a few meters using time signals transmitted along a line-of-sight by radio from satellites. Receivers on the ground, air, or water calculate the precise time as well as position, which can be used as a reference for scientific experiments and numerous everyday applications.Currently, the Navstar Global Positioning System (GPS) of the United States, the Global Navigation Satellite System (GLONASS) of the Russian Federation, and the People’s Republic of China BeiDou/Compass navigation system are the three fully operational global GNSS. The European Union’s Galileo positioning system is a GNSS in the initial deployment phase, scheduled to be operational in 2014. The global coverage for each system is generally achieved by a constellation of 24–30 Medium Earth Orbit (MEO) satellites distributed between several orbital planes. The actual systems vary but use orbit inclinations greater than 50° and orbital periods of roughly 12 h (height 20,000 km/12,500 miles). These global systems are being joined by the regional Quasi-Zenith Satellite System (QZZS) of Japan and the Indian Regional Navigation Satellite System (IRNSS) of India. These regional systems utilize satellites at smaller inclinations in elliptical orbits with apogees around 24,000 and 39,000 km or in inclined geostationary orbits at around 36,000 km. As accuracy in position, time, or speed measurements increases with the number of satellites that can be observed by a receiver, the signals received from the global GNSS satellites are complemented by signals provided by satellite-based augmentations systems (SBAs). Such is the motivation for the Wide-Area Augmentation System of the United States, the System for Differential Correction and Monitoring (SDCM) of the Russian Federation, the European Geostationary Navigation Overlay Service (EGNOS), the GPS and Geo-Augmented Navigation system (GAGAN) of India, and the Multifunctional Transport Satellite (MTSAT) Satellite-based Augmentation System (MSAS) of Japan. Altogether, by 2020 there will be around 120 navigation and positioning satellites in orbit at any given moment. It is possible that a user could receive signals from as many as ten satellites, leading to accuracies only available at the research level today. This chapter presents the characteristics of all current and future generations of navigation and positioning satellites.

This chapter introduces the subject of remote sensing both in terms of its technology and its many applications. Remote sensing via satellite has become a key service that is used in many civil applications such as agriculture, forestry, mining (and prospecting for many types of resources), map making, research in geosciences, urban planning, and even land speculation. Perhaps, one of the most vital uses of remote sensing today is related to disaster warning and recovery. The first use of remote sensing was essentially for military purposes and this remains the case today, and, thus, this chapter addresses these applications as well. Remote sensing, Earth observation, related geographical information systems (GIS), plus the interpretation and use of this type of data are today often referred to today as Geomatics.This section starts with a history of remote sensing and then continues with a discussion of the technology and its applications. In a number of ways meteorological or weather satellites are essentially a specialized form of remote sensing satellites. Thus the history presented here covers not only what are considered remote sensing satellites but meteorological satellites as well. The meteorological satellites are discussed in much greater detail later in this handbook.

Here, we consider a topic which is absolutely central to the successful operation of all satellites and spacecraft, namely, the basic principles and fundamental concepts of visible light in particular and of electromagnetic radiation in general. Both the wavelike nature of light (the speed of light being 300,000 km/s through free space) and its particle-like nature (as photons) are considered. We introduce its wave properties which explain the phenomena of reflection, refraction, diffraction, interference, polarization, and the Doppler effect. The photon properties explain blackbody radiation, continuous spectra, emission spectra, absorption spectra, and the photoelectric effect. We mention how electromagnetic radiation is used actively for radio communications with Earth-orbiting satellites and passively for remote sensing investigations not only of the atmospheres of the Earth and other planets but also of distant stars and the structure of Universe.

Photographic observations of the Earth by humans in low earth orbit, in contrast to unmanned orbital sensor systems, began during the 1960s as part of both the USA and former USSR manned space flight programs. The value of regularly repeated photographic observations of the Earth from orbit was demonstrated by later long-duration missions and led directly to the development of unmanned, multispectral orbital sensors such as the Multispectral Scanner and Thematic Mapper on board the Landsat series of satellites. Handheld imagery of the Earth has been continually acquired during both USA and USSR/Russian space station and former Space Shuttle programs and represents a rich dataset that complements both historical and current unmanned sensor data for terrestrial studies. This revised chapter provides an overview of astronaut/cosmonaut imagery and development of specific data collection programs, then moves on to discussion of technical aspects of both the historical film and current digital cameras used in orbit with information on how to access online datasets. Case studies are presented to highlight varied applications of handheld imagery for terrestrial research and natural hazard monitoring. Developments in time-lapse sequence photography, full georeferencing of astronaut photographs, and involvement with international disaster response efforts are discussed. The chapter concludes with discussion of future directions for digital handheld imagery of the Earth from manned orbital platforms such as the International Space Station (ISS).

Remote sensing satellites have become increasingly sophisticated in terms of increased spatial, radiometric, and temporal resolution. Over the past few decades, sensing devices have become more sophisticated with not only higher spatial resolution but have also now become more capable at capturing data in much more precisely defined bandwidths or frequency ranges. This provides the ability to identify particular vegetation, forestry, wildlife and fish, and minerals – even camouflage – with greater precision.This evolution of sensor capabilities has, however, led to new needs on the ground in terms of interpreting the data. The new interpretative needs – because much more data is captured – involve requirements for new and faster processing techniques on the ground. Or it has led to the need for “preprocessing of data” (i.e., discarding noncritical or nonmeaningful data) before being downloaded from the satellite. The point is that the more capable sensors that collect a larger amount of data serves to alter the way the torrent of data downloaded from the sky is processed. This chapter explains the transition that is rapidly occurring in terms of the transition from multispectral imaging to the much more precise and data-intensive hyperspectral sensing – also called imaging spectroscopy.Much more capable electro-optical arrays – usually using charge-coupled devices (CCDs) – allow the capturing of hyperspectral data much more efficiently. In the past with multispectral sensing data was collected in perhaps five or perhaps as many as ten broad frequency bands. Now data can be collected in much more precise and narrower frequency bands in the infrared, near-infrared, visible spectrum, and even ultraviolet bands.This chapter discusses the transition from multispectral to hyperspectral sensing that is now in full swing. It notes that the first uses of hyperspectral sensing were for military and defense-related purposes, but now hyperspectral sensing – using the latest electro-optical arrays – is becoming central to civil Earth Observation programs. This transition has not only meant a change in the imaging process and the types of sensor devices included on remote sensing satellites, but it has also signaled the shift in data processing formats with data being processed as “data cubes.” In this format spatial data is provided along the (X, Y axis), while the various frequency bands are displayed on the vertical or Z axis.

This chapter provides some examples of the operational uses of satellite radar images. These include the uses of polarimetric radar images for crop classification and earthquake damage assessment, radar image fusion for mineral exploration, interferometric SAR techniques for landslide and volcanic monitoring, multidate radar image enhancement techniques for oil spill monitoring and flood mapping, and sea ice mapping from enhanced ScanSAR images. In the near future, new applications will be developed from current and future advanced SAR missions involving their high resolution, rapid revisits, and polarimetric capabilities.

Light detection and ranging (LiDAR), also known as laser detection and ranging (LaDAR) or optical radar, is an active remote sensing technique which uses electromagnetic energy in the optical range to detect an object (target), determine the distance between the target and the instrument (range), and deduce physical properties of the object based on the interaction of the radiation with the target through phenomena such as scattering, absorption, reflection, and fluorescence. LiDAR has many applications in the scientific, engineering, and military fields. LiDAR sensors have been deployed at fixed terrestrial stations, in mobile surface and subsurface vehicles, lighter-than-air crafts, fixed and rotary wing aircraft, satellites, interplanetary probes, and planetary landers and rovers. This chapter provides a high-level overview of the principles of operation of LiDAR technology and its main applications performed from space-based platforms such as satellite altimetry, atmospheric profiling, and on-orbit imaging and ranging.

Airborne and satellite digital image acquisition, preprocessing, and data reduction techniques as applied to remotely sensed data for the purpose of extracting useful Earth resources information are discussed in this chapter. The image processing and postprocessing tools are described in the next chapter. The concepts discussed in this chapter include:Image acquisition considerations including currently available remotely sensed dataImage characteristics in terms of spatial, spectral, radiometric, and temporal resolutionsPreprocessing techniques such as geometric distortion removals, atmospheric correction algorithms, image registration, enhancement, masking, and data transformationsData reduction, fusion, and integration techniquesInternational policies governing acquisition and distribution of remotely sensed data

Digital image processing, post-processing, and data integration techniques as applied to airborne and satellite remotely sensed data for the purpose of extracting useful Earth resources information will be discussed in this chapter. Image preprocessing and data reduction tools are described in the previous chapter. The concepts discussed in this chapter include:Image processing techniques such as unsupervised image classifications, supervised image classifications, neural network classifiers, simulated annealing classifiers, and fuzzy logic classification systemsThe most widely accepted indices and land use/land cover classification schemesPost-processing techniques such as filtering and change detectionAccuracy assessment and validation of resultsData integration and spatial modeling including examples of integration of remotely sensed data with other conventional survey and map form data for Earth observation purposes

Application areas of remote sensing are very wide. They can be divided into two areas. One is applications in the Earth environmental monitoring and process studies of the Earth system, and another is operational applications. The former can be divided into atmosphere, ocean, land, cryosphere, and their interactions. In this chapter, temperature, water vapor, aerosols and clouds, atmospheric constituents, greenhouse gases, sea surface temperature, sea surface salinity, sea surface wind, ocean color, sea surface height, topography, land cover, soil moisture, carbon cycle, sea ice, snow, and glaciers are described. The latter has wide variety. This chapter cannot cover all the operational application areas. Among them, NWP and weather forecasting, fisheries, disasters such as biomass burnings, floods, ship navigations, and agriculture are described. In addition to these application areas, some basic processings for applications are also described. These processings include radiative transfer and inversion problem, geometric and radiometric corrections, and classification algorithms.

The role of spatial data for decision making has increased the need for geographic information systems. This chapter starts by briefly describing the theory of geographic information systems. After that we present the interactions of geographic information systems with remote sensing and global navigation, positioning, and timing satellite systems. This is done with the idea to illustrate how geographic information systems (GISs), remote sensing, and global navigation satellite systems work together in order to generate final products. Then, we focus on the capability of GIS to analyze spatial data. We finally present examples of applications of GIS and current trends of research in the area. The examples presented through this chapter capture how GIS can be used for decision-making tasks in different areas of knowledge.

Hyperspectral remote sensing is a relatively new development in remote sensing technologies, effectively measuring both spatial and high spectral information from surface materials and constituents within a single system. Compared to multispectral remote sensing, hyperspectral imagery can provide more accurate and detailed spectral information of the Earth’s surface, measuring hundreds of bands from the visible to the near infrared. Hyperspectral data can be obtained using either space-based or airborne platforms, with expanding applications on unmanned aerial vehicles (UAVs). This chapter discusses hyperspectral technologies and their vast applications focusing primarily on airborne and spaceborne systems, reviewing past and future directions of sensor technology developments. Hyperspectral imaging is a rapidly growing field of space-based remote sensing and will continue to expand in utility for various civilian and public-good applications. Various nations are planning hyperspectral remote sensing missions, which will see increased acquisition of hyperspectral data of the Earth’s surface on a more frequent and timely basis in the near future.

The world’s meteorological satellite systems are today vital to every nation in the world not only for reliable weather forecasts but also for key storm warnings and potential disaster alerts in the case of hurricanes, tornadoes, typhoons, monsoons, floods, and other violent and potentially lethal meteorological events. Since the advent of polar-orbiting and geosynchronous meteorological satellites, the ability to predict weather accurately and reliably, forever longer periods of time, has increased to a remarkable extent. With a diverse suite of sophisticated instruments, meteorological satellites also gather essential data for climate change studies as well. The first systems were pioneered by the USA and by NASA experimental satellites, but over time Europe, Russia, Japan, China, and India have evolved increased capabilities to monitor weather systems using increasingly sophisticated imaging systems. Today, this allows effective sharing of meteorological data on a global scale. The combination of polar orbiting and geosynchronous satellites has allowed higher resolution images to be combined into accurate regional and global displays to see broad patterns of weather formations. New capabilities such as lightning intensity mapping have allowed greater capability to predict storm patterns in near real time and thus identify rapidly where the most violent and more energetic storm fronts are headed.The global sharing of meteorological data and the combined imaging of international meteorological satellites have not only greatly contributed to effective long range weather forecasting on land and in the oceans but have also allowed the collection of data to monitor longer-term conditions associated with climate change, global warming, and increases in aridity in some regions and increased rainfall in others. In short, meteorological satellites have evolved, particularly in the last decade, to serve an important role in not only short- to medium-term weather forecasting but also to provide important data with regard to national, regional, and global environmental assessment and analysis including the major ocean conditions known as La Niña and El Niño.The value of meteorological satellite systems and other Earth observation satellite systems for measuring the internationally recognized essential climate variables (ECVs) and for monitoring changes on land, oceans, and atmosphere is greatly increased when the acquired data is made available to national and international user organizations. A study by the International Academy of Astronautics recommends, among other things, that space agencies, companies, universities and nongovernmental organizations, and other international bodies already acting for the coordination of space agencies in the area of climate monitoring should work together to guarantee over time the continuous operational availability of the space sensors and datasets that are necessary for the monitoring of the space-observable ECVs (International Academy of Astronautics, in Study on Space Applications in Climate Change and Green Systems: The Need for International Cooperation, November 2010, eds. J.C. Mankins, M. Grimard, Y. Horikawa, ISBN EAN 9782917761113, pp. 15–21). Such cooperation is aimed at reinforcing the programmatic coordination of the Earth science programs worldwide, in the frame of institutions such as the Group on Earth Observations (GEO) and the Committee on Earth Observation Satellites (CEOS), with the goal of guaranteeing the continuous long-term availability for all nations of all space-observable ECV, as defined by the global climate observing system (GCOS); and contribute to the elaboration and implementation of GEO data sharing principles (http://www.earthobservations.org/art_015_002.shtml).Despite patterns of data sharing and international cooperation with regard to data collection by meteorological satellite systems, there are limits to full disclosure of all satellite data. In particular, there remain certain areas of strategic concern in the context of possible military or defense-related use of meteorological and remote sensing data in the case of hostilities. It is partially because of these strategic and national defense-related concerns that so many different meteorological satellite systems have been deployed and why some parts of the imaging might be encrypted in a manner so that all data that is collected may not be in all instances fully shared. Despite these strategic concerns and interests, most meteorological satellite imaging data is today widely shared and global cooperation is quite universal.The areas of satellite communications, remote sensing, and satellite navigation have all – to some degree – evolved toward more commercialized economic models and thus have become more oriented to competitive markets. This is not to say that these other space applications services are fully commercialized since there are some well-defined military, defense, and governmental services for satellite communications, remote sensing, and satellite navigation that remain as “publicly provided services.” In the case of meteorological satellites, however, these space applications remain almost entirely as governmental services.Despite discussions and analysis of how meteorological services might transition to commercial service providers within the USA, the provision of space-based meteorological services seems likely to remain as essentially a “public good” and not completely commercialized in any spacefaring nation. Although many countries, private businesses, and individuals derive major benefits from meteorological satellite images, no viable economic model has yet evolved whereby these services might be fully commercialized.The US National Oceanic and Atmospheric Administration (NOAA), however, is currently evolving a new commercial space policy that mentions possible conditions whereby either “hosted payloads” on commercial satellites or certain routine, operational space functions might be transferred to the commercial space sector – perhaps on a temporary basis. The particular focus in this regard refers to potential future gaps in US polar orbiting meteorological satellite coverage that could occur in 2017. This potential commercialization of some meteorological satellite services in the U.S. is discussed later in this section.In the chapters that follow specific information about various national and regional meteorological satellite systems will be presented. This introductory chapter provides a quick overview of the various systems that have evolved over time and some information perspective on how these systems are coordinated and work together through the World Meteorological Organization (WMO) and the World Weather Watch (WWW) program (World Meteorological Organization http://www.wmo.int/pages/index_en.html also see “Lessons Learned about the Integrated Global Observing Strategy through the World Weather Watch” http://www.un.org/earthwatch/about/docs/igusland.htm).

Over the past half century, weather and sophisticated environmental imaging satellites have evolved providing an increasing ability to monitor a wide range of conditions on Earth. A long-term and effective partnership between the National Aeronautics and Space Administration, the US space agency, NASA, and the National Oceanic and Atmospheric Administration, NOAA, has worked to design, launch, and operate a series of environmental monitoring satellites. These environmental monitoring satellites have grown in their technical capabilities to monitor cloud coverage, temperature, and wind velocity over the oceans and seas, lightning intensity, and storm formations. Interactive capabilities have for some time allowed these satellites to assist with the monitoring of climate change, space weather, and search and rescue activities. In short, the expanded technical capabilities of these satellites, and particularly of the Geostationary Operational Environmental Satellite system, have allowed the development of an ever increasing range of applications and functionality.The initial US meteorological or weather satellite program that began with TIROS created a specific type of remote-sensing satellite that could assist in monitoring weather conditions for the continental USA. Today’s GOES and Polar-Orbiting Environmental Satellites (POES) have now grown to become global in scope. These US satellites allow the development of an increasingly wide range of knowledge of the oceans and the Polar region, allow for more accurate mathematical models of meteorological conditions, help to monitor “space weather” conditions, assist with rescue of distressed ships and aircraft, aid transportation systems, and help with monitoring atmospheric pollution and conditions associated with climate change.The National Ocean and Atmospheric Administration, through its National Environmental Satellite, Data, and Information Service (NESDIS), continuously operates a global network of satellites to achieve these goals. NOAA works closely with NASA in the design of environmental satellites and cooperates with the US Department of Defense in obtaining and distributing environmental information. Data obtained from US environmental spacecraft as well as from other spacecraft around the world are used for a wide range of applications. Currently these applications relate to the oceans and seas, coastal regions, agriculture and resource recovery, detection of forest fires, detection of volcanic ash, monitoring the ozone hole over the South Pole, and even the space environment in terms of the so-called space weather such as solar flares.Each day NOAA’s NESDIS processes and then distributes more than 3.5 billion bits of data. The processed images are distributed to weather forecasters in the USA and globally so that various users, for instance, disaster managers, and the general public can see weather patterns via television or on computer or smart phone displays. The timeliness and quality of the combined polar and geostationary satellite data have been greatly improved by enhanced computer installations, upgraded ground facilities, and international data sharing agreements as well as by military weather services.

The oldest and most extensive meteorological satellite systems are those of the USA and of Europe, as operated by the Eumetsat system. These are addressed in detail in the preceding two chapters. This chapter describes the meteorological satellite systems of China, India, Japan, Russia, and South Korea. These meteorological satellite systems are extensive and provide a number of sophisticated meteorological satellite sensing capabilities both from geostationary and polar-orbiting satellite systems. Today all of these various satellite systems – those of China, Europe, India, Japan, Russia, South Korea, and the USA – are in various manners linked together and share data. This international coordination of meteorological data is accomplished through the World Weather Watch (WWW) programme of the World Meteorological Organization and the Coordination Group for Meteorological Satellites (CGMS).These international cooperative efforts – supplemented by bilateral or regional agreements – allow a degree of standardization with regard to the formatting and display of meteorological data and a systematic process for sharing of vital weather data. This sharing of meteorological data is important on an ongoing basis – but this can be particularly important – when there is a failure of a meteorological satellite, a launch failure, or a delay in the deployment of a replacement satellite. In some cases, countries such as the USA have even “loaned” meteorological satellites to other countries when failures or launch delays have created gaps in critical coverage areas.The various international satellites around the world that are deployed in different orbital locations and with varying periodicity provide a very useful redundancy of coverage that is particularly important in tracking major storms and obtaining the most up-to-date information of atmospheric, oceanic, and of arctic conditions.This chapter provides a description of the meteorological satellite systems of China, India, Japan, South Korea, and Russia and their current status. Researchers can also consult the various universal reference locations (i.e., URLs) for these various meteorological satellite systems which can be useful in obtaining the more recent information about the deployment and operation of these systems.

One of the important new developments in commercial and governmental satellite systems is the active deployment of hosted payloads. The prime reason for the use of hosted payloads is to save costs and avoid the expense of a more costly dedicated mission. The hosted payload approach may involve the deployment of experimental packages that are typically only a one-of-a-kind project, or it can involve many operational packages that are “piggybacked” on a large low earth orbit constellation with many satellites so equipped. This is an approach that has been particularly promoted within US space programs in response to the US 2010 official space policy. This White House policy emphasized the use of hosted payloads, where cost savings and operational efficiency so allowed. This approach to the use of hosted payload is also being employed around the world by many different entities for a variety of purposes.Examples provided here include the IRIS experiment that was included on an Intelsat satellite, the Anik G1 with an X-band package, the WAAS package that flew on the Galaxy 15 satellite and the UHF package that is flying on the Intelsat 22 satellite. Another example of the specialized package flying as a hosted payload is the case of those experiments that are currently flying on the large Inmarsat Alphasat. The above examples typically involve very specific individual hosted payload packages.There can be much different type programs where the hosted payload approach involves the deployment of a small operational package on each of a number of satellites within a large-scale satellite network. In this case the example provided is with regard to the Aireon packages that are being deployed with the Iridium NEXT Satellite System.A decade ago, the hosted payload approach was a very occasional and unusual approach and most often involved a one-of-a-kind experimental package, but today “hosted payloads” have become a much more common practice with large companies such as Intelsat General and SES even having dedicated units that focus exclusively on hosted payload activities. Annual conferences on the topic of hosted payload now draw many hundreds of attendees. This growing interest in hosted payload flying on satellite networks has also led to the formation of the Hosted Payload Alliance with a quite large and growing global membership. In short, hosted payload activities in the course of the past decade have become a big business involving a large number of satellites and significant spacecraft and ground system investment.This chapter addresses the various types of hosted payload activities that are now in progress or planned and provides some analysis of the reasoning behind various hosted payloads and the pros and cons of such undertakings. This analysis considers not only the impact on capital investment, speed of implementation, launch costs, operational costs, and advantages and risks that are associated with various host payload projects that have become a part of the application satellite industry. In many instances the use of hosted payload strategies has been employed in governmental, military, and commercial programs to test new capabilities. Also governmental and military programs have flown on commercial satellite systems.Somewhat akin to the concept of hosted payloads is the concept of incremental or supplemental payloads that are secondary or even tertiary payloads that are launched as add-on to primary launch operations as part of a single launch deployment into outer space. This “piggybacked” launch operation can lead to cost savings, but this proliferation of smaller satellites in orbit can add to the growing problem of orbital debris.Consolidation of smaller payloads such as student experimental packages by placing them on a larger satellite as hosted payload or flying them to the International Space Station and returning them after the experiment is finished is now a common practice. This use of NanoRacks type experiments that fly on the International Space Station in particular can be highly cost effective, allows astronaut oversight of experiments, and eliminates orbital debris issues.

The first half century of satellite applications has entailed rapid technological growth with the deployment of bigger, better, and more sophisticated satellites that have responded to rapidly expanding space application markets. The development of more reliable and higher-capacity rockets with increased lift and higher cost efficiencies has generally reinforced the trend to always seek new economies of scope and scale.Currently, however, there are widely diverging thoughts about “What Next?” Some feel that even larger high-throughput satellites and corporate consolidation and mergers are the way forward. Others are promoting growth through large-scale low earth orbit constellations with networks that might contain as many as thousands of application satellites in so-called mega-LEO systems. Others are increasingly concerned about orbital debris and the need for active debris removal and improved deorbiting systems. Yet others are being to think that on-orbit repair and servicing of application satellites to extend their usable life may represent yet another important new development.New techniques associated with on-orbit servicing and repair have begun to emerge in the last few years. There have been many proposed new ways forward. These proposals include refueling of satellites with depleted maneuvering systems, redeployment of satellites from low earth orbits that failed to reach GEO, and even repurposing of components on derelict satellites such as large aperture antennas or solar power systems to create new and cost-effective satellites in space rather than deorbiting them as space debris. These redeployments, repair, or augmentation of defective satellites, and even repurposing of parts from derelict satellites to create new spacecraft, could offer new economies of scale to make satellite applications more cost-effective and extend usable lifetimes. This capability might be critical to coping with orbital space debris problems.It is noteworthy to understand that some of the techniques and capabilities needed to undertake on-orbit servicing, repair, or satellite upgrades are quite parallel to the capabilities needed to undertake active orbital debris removal or mitigation. This chapter examines some of the new capabilities that are being developed to carry out on-orbit servicing, repair, or repurposing. This chapter also include some brief discussion of how these technologies might be commercially applied to space debris mitigation and active removal techniques – and in the relatively near future.

This chapter gives an overview of a sector of satellite technology which is rapidly developing and has to be taken into account when planning a new space mission. Additive manufacturing, usually called 3D printing, is extremely well adapted to the constraints of spacecraft development, therefore quickly gaining acceptance in the field of space technology. But 3D printing is not the only innovative technology that may change the way that satellites will look like in the future. In addition to the expected continuous integration of electronics, new materials, and even meta-materials, associated with new manufacturing techniques, will give the designer a renewed freedom to design more powerful and innovative space systems.

The issue of space debris has become one of increasing concern as the amount of orbital debris, sometimes known as “space junk,” has become more severe, especially in low Earth orbit and in the polar orbits used for communications, remote sensing, and meteorological sensing and forecasting. The Chinese missile shootdown of the defunct Fung-yen (FY-1C) weather satellite in 2007 and the collision of the Iridium and Cosmos satellites in 2009 have greatly heightened this concern. Increasingly sophisticated tracking systems have been implemented by the US Air Force Strategic Command, the European Space Agency, and several affiliated national tracking systems to cope with the complex space situational awareness (SSA) challenge that is now presented by rising amount of space debris. A new S-band radar “Space Fence” system and other optical tracking systems in Australia and other parts of the world are being implemented to cope with this task.The new S-band Space Fence system that is currently being installed in the Kwajalein Atoll in the Pacific, in particular, will allow an increase in the tracking ability for space debris. This increased tracking ability will thus rise from about 23,000 debris elements that are 10 cm or larger (i.e., about the size of a baseball) in low Earth orbit to well over 200,000 elements that are greater than 1 cm in diameter (i.e., about the size of a marble) in low Earth orbit. The Space Data Association, which has been formed by commercial satellite operators, is also increasingly able to share information among themselves in order to minimize the possibility of collisions and to be aware of close satellite conjunctions in a timely manner. Their tracking capabilities are currently provided by a commercial capability operated by Analytic Graphics Inc. (AGI).In addition new laws and national regulations as well as guidelines adopted by the Inter-Agency Space Debris Coordination Committee (IADC) and the UN Committee on the Peaceful Uses of Outer Space (COPUOS) to ensure that all satellites are deorbited within 25 years at the end of a spacecraft life represent another key step forward. There are clearly more steps that need to be taken to move toward better collision avoidance systems plus active deorbit and debris mitigation, especially of the largest debris elements from low Earth orbit. It is also key to ensure that the deployment of new large-scale constellations in low Earth orbit is accomplished with strict controls to minimize any new collisions that might occur within these constellations themselves or to avoid collision with defunct debris elements. The addition of constellations with perhaps a thousand small spacecraft or more in just one constellation has given rise to particular new concerns in this regard.In addition, there needs to be (i) new and better international collaboration to strengthen all elements associated with the more precise tracking of debris in all Earth orbits; (ii) more control processes to prevent debris increase and avoid the formation of new debris elements, including the active deorbit of all launch systems after they have inserted spacecraft into orbit; (iii) better coordination of information among satellite system operators through such mechanisms as the Space Data Association as its membership and participation levels grow; and (iv) new technology and international agreements and perhaps commercial arrangements to incentivize the active deorbit of space debris in future years consistent with existing space treaties and international agreements.This chapter addresses in some detail the various tracking capabilities that exist or are planned around the world to monitor the orbits of space debris and to provide alerts so as to avert possible conjunctions. It provides information about how these systems are being upgraded and space situational awareness (SSA) capabilities are being coordinated over time. It notes how governmental systems are being augmented by private capabilities that are able to augment space situational awareness and to assist with avoidance of collisions. These systems and processes will perhaps assist with future space debris mitigation and active removal. All of these increasing space situational awareness capabilities are crucial to the future successful operation of application satellites in the twenty-first century.

The evolution of application satellites has hinged on the development of more and more sophisticated spacecraft buses or platforms. The development of three-axis body-stabilized platforms have allowed the deployment of more capable and much higher gain communications antennas, high resolution remote sensing and meteorological sensors, and more precise navigational payloads. The most important development in spacecraft buses has been the development of precisely oriented body-stabilized platforms that allow the deployment of very high-powered solar arrays and very accurate pointing of high-gain antennas and sensor systems. Other challenges have included developing lower mass and structurally strong spacecraft bodies, improved and longer life thrusters, better performance power systems with greater density of charge, and improved thermal control systems. This chapter explores the development of the spacecraft bus and their technologies. The following chapters discuss tracking, telemetry, and command; reliability testing; and the adaptability of essential multipurpose platforms to different applications.

The telemetry, tracking, and control (TT&C) subsystem of a satellite provides a connection between the satellite itself and the facilities on the ground. The purpose of the TT&C function is to ensure the satellite performs correctly. As part of the spacecraft bus, the TT&C subsystem is required for all satellites regardless of the application. This chapter describes the three major tasks that the TT&C subsystem performs to ensure the successful operation of an applications satellite: (1) the monitoring of the health and status of the satellite through the collection, processing, and transmission of data from the various spacecraft subsystems, (2) the determination of the satellite’s exact location through the reception, processing, and transmitting of ranging signals, and (3) the proper control of satellite through the reception, processing, and implementation of commands transmitted from the ground. Some advanced spacecraft designs have evolved toward “autonomous operations” so that many of the control functions have been automated and thus do not require ground intervention except under emergency conditions.

The environment of outer space is quite hostile to the many spacecraft that are now deployed in Earth orbit and beyond. There are many hazards in terms of severe thermal gradients, space weather from the sun and beyond, and intense radiation from the Van Allen belts as well as strong magnetic forces. Today, application satellites also must plan to cope with man-made hazards that arise from space debris, RF interference (RFI), and other possible hazards such as spurious commands. There are also risks associated with the launch and deployment of satellites since there are strong “g forces” during launch and difficulties that can arise from the unfolding, roll-out, or explosive or spring-loaded extension of solar arrays, antennas, and other systems that must be deployed in space in response to remote command. This complex series of hazards requires extensive testing of application spacecraft that are deployed into Earth orbit with the hope of extended lifetime operation. These hazards and difficulties of space operations increase the importance of lifetime testing. It also demands the design of application satellites to be rugged and to have reasonable levels of redundancy so that service can be maintained if various components happen to fail. In the case of application satellites, rugged design, redundancy, and demanding lifetime testing of applications satellites and its subsystems and components are of utmost importance simply because there is little opportunity for repair or refurbishment operations in space. Without these precautions, a very expensive application satellite that requires perhaps an even larger investment to launch it into space could be lost to the satellite operator and thus require replacement at very high cost either to the satellite operator or to the companies that have insured the launch and operation of the satellite.In recent years, there has been an alternative approach taken in terms of deployment of large constellations of small satellites in space as an alternative to a few large satellites designed and tested for long life. These small satellites have been built at much lower cost using off-the-shelf components and most frequently by advanced manufacturing techniques that include 3-D printing. These have frequently been launched as “piggyback” missions and thus at much lower cost.Networks such as Skybox Imaging, Planet Labs, PlanetiQ, Dauria Aerospace, Tyvak Nano-Satellite Systems, NovaWurks, and GeoOptics have all emphasized this approach that involves miniaturization, low-cost satellites, and associated modest launch costs over larger and more capable satellites that subjected to extensive lifetime testing prior to launch. This new paradigm is also now being tested by new communications satellite operators such as OneWeb that proposed to nearly 800 mass-produced satellites plus spares to create a network optimized for Internet-based services, and a megaLEO constellation by SpaceX might ultimately involve thousands of small satellites. For this type of alternative design architecture, the replacement of failed satellites with a ready supply of spares is the key to achieving system reliability. This approach is seen as the alternative to stringent testing and flight-qualified components with proven long-life capabilities in a stringent space environment.The following text discusses all of these strategies for coping with and minimizing risk for the satellite application industry although the much greater emphasis is on the stringent reliability and long-life design approach, since the ventures employing a constellation of small satellites largely depend on a robust sparing effort.

The technology, the applications, and the economic forces that have driven the design, functionality, and performance of ground systems for satellite communications have been very closely mirrored in the other major application satellite services. It is for this reason that this chapter combines consideration of the ground systems for satellite navigation, remote sensing, and meteorology. In essence, all the ground systems for the various applications are communication systems. Although the radio frequencies, modulation, and multiplexing methods and encryption schemes utilized vary for a variety of reasons – including defense and military-related consideration – all application satellites employ satellite communications between the spacecraft and the ground system. Some systems are broader or narrower in bandwidth and some only involve downlinks, while others are more interactive with up- and downlinks.The common elements that range across the ground systems for all application satellites include the following:All application satellites have become higher in power, more accurate in their stabilization and pointing of their onboard antennas, and better able to deploy higher gain and larger aperture reflectors. This has allowed ground systems to be smaller, more compact, lower in power, lower in cost, and more widely distributed.Downlinked information is often encrypted to protect the integrity of information and data relayed from the satellite – particularly if there is a proprietary or defense-related application for the downlinked information.Solid-state digital technology associated with integrated circuitry, application-specific integrated circuits (ASICs), and monolithic devices that have allowed the ground systems to be more highly distributed.There are essentially two tracks in ground system development – one where geosynchronous satellites are involved and the ground system can be constantly pointed toward a single fixed point in the sky and the other where the ground system must have the ability to receive signals across the horizon and capture signals from a satellite that moves across the sky. Both types of ground receivers suited to “fixed” or “non-fixed” signal reception are needed in satellite communications, remote sensing, meteorological satellites, and satellite navigation.In addition to the user terms associated with different types of applications, there is a need for a tracking, telemetry, and command system to ensure the safe operation of the application satellite.Despite these elements of commonality, there are indeed differences in the ground systems, the antenna characteristics, their tracking capabilities, the frequency utilized, the degree to which the data is protected by encryption, and the need for expert analysis of the data received from the spacecraft.

The concept of developing a handbook on satellite applications is based on the concept that all of the commercial and practical applications of space have many elements in common. In fact very similar power systems, spacecraft platforms, stabilization and positioning systems, and tracking, telemetry, and command systems are used for the various types of application satellites. It is the payloads that tend to be quite specialized. Even in the field of telecommunication satellites, quite different antenna systems and communications subsystems are now developed and deployed for various satellite systems for satellite broadcasting, fixed, or mobile services. It is equally true that different types of remote sensing, space navigation, and meteorological satellites can and do have different payload designs. The purpose of this chapter is to contrast and compare different types of application satellites to note major areas of similarities as well as how and why differences occur. Such an analysis is useful to understand where the most promising common elements lie in order to aid identifying new potential synergies for future research and development in order to seek out improved methods for common forms of reliability testing, sparing and redundancy strategies, as well as lifetime extension and reduced operating and monitoring costs.

The Handbook of Satellite Applications focuses on the practical applications of satellites. This means that the handbook addresses the many uses that are made of communications, remote sensing, satellite navigation, and meteorological systems as well as the spacecraft, the ground systems, and tracking, telemetry, and command systems that make these networks possible. There are also chapters that address regulatory issues, economic and insurance issues, and even threats to the future operation of application satellites. This chapter addresses the remaining critical areas that are critical to the successful operation of application satellite systems.All types of applications satellites could not carry out their function unless they were first launched into the right orbit. Even after successful launch they must also be properly maintained there through necessary station-keeping operations. This chapter addresses the history of rocket and launch vehicle development and explains the basic technical capabilities that allow applications satellites to be placed into orbit with greater and greater reliability. This chapter also briefly addresses in-orbit operations that allow spacecraft to be maintained in orbit and to operate over increasingly long practical lifetimes. Over the past 60 years of the space age, an expanding variety of different propulsion systems and launch systems have been developed to carry out the important tasks of launch, station-keeping, and deorbit or removal of spacecraft to a graveyard orbital location.One of the key elements of success for applications satellites of all types is the fact that gradually the reliability and the lift capability of launch vehicles have improved over time. It has been hoped for many years that new technology could allow the cost of launches to be significantly reduced, but to date such breakthroughs in the economics of launch systems have not yet been achieved. The precision thruster systems that allow spacecraft to be pointed with ever greater precision and to maintain crucial station-keeping have quite successfully continued to evolve. This has allowed application satellites to operate for much longer lifetimes and with greater pointing accuracy that has increased their functionality. Further developments that have most recently occurred in launch systems and new commercial launch sites are addressed in the following chapter.

The development of more reliable and lower cost launch capabilities has been the steady and consistent objective for a rocket scientist for many decades. Indeed, ever since the first rocket launcher capabilities were proven by Goddard, von Braun, and other early pioneers, the goal has been to create a better launch vehicle. For the past 50 years, however, the prime development work has largely been defined by developing improved chemically powered launch vehicles. The prime development efforts for solid missile systems have been driven by military programs, while liquid-fueled rockets were largely spear-headed by aerospace companies supplying launchers for civil aviation programs. During the past 2 decades, a growing capability to deliver reliable launch services has grown up in the world with Japan, China, India, and the Ukraine offering capabilities that rival the governmental programs of the USA, Europe, and Russia.The biggest change of all has been the advent of “new space” entrepreneurial companies seeking to develop new lower cost and human-rated spaceplanes and highly competitive launch vehicles. These new commercial initiatives have served to alter the course of launch vehicle development in a variety of ways. New cost models and new commercial applications have driven thought in new ways. Areas of focus now include consideration of new ways to use electric ion propulsion, nuclear ion propulsion, and the development of hybrid systems that combine solid fuels with an oxidizer in such a way to allow hybrid propulsion systems to be turned on and off. Other new concepts include more efficient ways to launch from higher and more efficient altitudes by using balloons, carrier vehicles, or even towing launch systems to airborne launch sites. Another key area of research involves the ability of launch systems to be reused so that the rocket launcher can return to a launch site to be used over and over again. This is in addition to spaceplanes that can be used for multiple missions.At the research level, there are in fact over a dozen innovative ways that spacecraft and payloads could be placed into earth orbit. These range from concepts that have been actively researched by space agencies such as using nuclear heat to create ionic propulsion to exotic ideas for the future such as mass drivers, tether sky hooks, and even space elevators.And in addition to plans to make launchers more cost-efficient, reusable, and reliable, there are also new concerns about the environmental effects of rocket launchers on the fragile upper atmosphere where the density of molecules is perhaps a 100 times less than at sea level. This has given rise to particular concerns about solid fuel rockets that emit particulates and are perhaps 100 times more polluting than liquid-fuelled systems.New entrants such as Swiss Space Systems (S-3), Virgin Galactic, Sierra Nevada, SpaceX, and External Engines, Firefly, Blue Origin, Copenhagen Suborbital, Kelly Space & Technology, inc., Myasishchev Design Bureau, Interorbital Systems, Armadillo (now Exos Aerospace), Masten, Planespace, Scaled Composites, Rocketplane Kistler, Stratolaunch, XCOR, t/Space, Space Transport Company, Zero2Infinity, and Starchaser Industries have all contributed to a wealth of ideas about new, lower cost, safer, and more reliable ways to launch to orbit. Some of these start-ups have now failed and are defunct but their innovative concepts live on (J.N. Pelton, P. Marshall, Launching into Commercial Space. AIAA, Reston, 2015).In this era of rapid innovation and change, established aerospace companies such as Boeing, Orbital ATK, Northrop Grumman, Arianespace, Astrium-Air Bus, Lockheed Martin, Raytheon, SeaLaunch, the United Launch Alliance, the Great Wall Company of China, and others are also seeking to innovate and create newer and better launch systems that keep current with the latest in launch technology and systems. In particular, they have been driven to find ways to cut cost in the face of new commercial space launch systems that their vehicles must compete (J.N. Pelton, P. Marshall, Launching into Commercial Space. AIAA, Reston, 2015).This chapter provides the latest updates on new launch systems and ends with a brief update about the impact of new commercial spaceports and launch sites.

The orbital particle environment around the Earth is dominated by man-made space objects, except for a limited particle size regime below 1 mm, where meteoroids provide a significant contribution, or may even prevail in some orbit regions. The mass of man-made objects in Earth orbits is on the order of 6,800 t, of which more than 99 % is concentrated in trackable, cataloged objects larger than typically 10 cm. The mass of meteoroids within the regime of Earth orbits is only on the order of 2–3 t, with most probable sizes around 200 μm. As a consequence of their size spectrum and associated mass, man-made space objects, in contrast with meteoroids, represent a considerable risk potential for space assets in Earth orbits. To assess related risk levels, a good understanding of the space debris environment is essential, both at catalog sizes and subcatalog sizes. The derivation process and the key elements of today’s debris environment models will be outlined, and results in terms of spatial densities and impact flux levels will be sketched for those orbit regions that are most relevant for space applications.To cope with the existing space debris environment, spacecraft can actively mitigate the risk of collisions with large-size, trackable space objects through evasive maneuvers. Alternatively, or in addition, the risk of mission-critical impacts by nontrackable objects can be reduced through shielding, in combination with protective arrangements of critical spacecraft subsystems. With a view on the future debris environment, international consensus has been reached on a core set of space debris mitigation measures. These measures, which will be explained in more detail hereafter, are suited to reduce the debris growth rate. However, even if they are rigorously applied, they are found to be inadequate to stabilize the debris environment. Long-term debris environment projections indicate that even a complete halt of launch activities cannot prevent the onset of a collisional runaway situation in some LEO altitude regimes. The only way of controlling this progressive increase of catastrophic collisions is through space debris environment remediation, with active mass removal, focused on retired spacecraft and spent orbital stages.

The issue of space debris has become one of increasing concern as the amount of debris has become more severe, especially in low Earth orbit and polar orbits used for communications, remote sensing, and meteorological sensing and forecasting. The Chinese missile shootdown of the defunct Fengyun (FY-1C) weather satellite in 2007 and the collision of the Iridium and Cosmos satellites in 2009 have greatly heightened this concern. Increasingly sophisticated tracking systems have been implemented by the US Air Force, the European Space Agency, and the several affiliated national tracking system, plus tracking systems in Australia and other parts of the world, and more radar and optical tracking systems are planned. The new S-band space fence system, in particular, will allow an increase of tracking of space debris from about 23,000 elements that are 10 cm or larger (i.e., about the size of a baseball) in low Earth orbit to well over 200,000 elements that are greater than 1 cm in diameter (i.e., about the size of a marble) in low Earth orbit. The Space Data Association that has been formed by commercial satellite operators is increasingly able to share information among themselves to minimize the possibility of collisions and to be aware of close conjunctions in a timely manner.In addition, new laws and national regulations as well as guidelines adopted by the Inter-Agency Space Debris Committee (IADC) and the UN Committee on the Peaceful Uses of Outer Space (COPUOS) to ensure that all satellites are deorbited within 25 years of the end of spacecraft life represent key steps forward. There are clearly more steps that need to be taken to move toward better collision avoidance systems plus active deorbit and debris mitigation, especially of the largest debris elements from low Earth orbit. It is also key to ensure that the deployment of new large-scale constellations in low Earth orbit is accomplished with strict controls to minimize any new collisions that might occur within these constellations themselves or to avoid collision with defunct debris elements. The addition of constellations with a thousand spacecraft or more in just one constellation has given rise to particular concerns in this regard.In addition, there needs to be (i) new and better international collaboration to strengthen all elements associated with the more precise tracking of debris in all Earth orbits; (ii) more control processes to prevent debris increase and avoid the formation of new debris elements, including the active deorbit of all launch systems after they have inserted spacecraft into orbit; (iii) better coordination of information among satellite system operators through such mechanisms as the Space Data Association as its membership and participation levels grow; and (iv) new technology and international agreements and perhaps commercial arrangements to incentivize the active deorbit of space debris in future years consistent with existing space treaties and international agreements.This chapter addresses in some detail the various tracking capabilities that exist or are planned around the world to monitor the orbits of space debris and to provide alerts so as to avert possible conjunctions. It provides information about how these systems are being upgraded, and space situational awareness is being coordinated over time. It notes how governmental systems are being augmented by private capabilities that are able to augment space situational awareness and to assist with avoidance of collision. These systems and processes will perhaps assist with future space debris mitigation and active removal. All of these increasing space situational capabilities are crucial to the future successful operation of application satellites in the twenty-first century.

Magnetic activity on the Sun causes disturbances moving out through interplanetary space as a stronger than usual solar wind. Enhanced solar activity can also produce large fluxes of penetrating energetic protons of great destructive potential. When either of these phenomena arrives near the Earth and strikes a satellite or spacecraft, damage is likely to be done, either directly and indirectly. Here, we give an overview of the several different effects which occur in low Earth orbit (LEO), in medium Earth orbit (MEO), and in geostationary orbit (GEO) as well as in high inclination elliptical Earth orbits where positioning satellites are located.

In the context of a launch vehicle re-entry, this is the burning off of material, usually thermal protection shielding, as a result of contact with the atmosphere.

There are over three dozen launch sites around the world. With the growth of the newly emerging spaceplane transportation and space adventures business, there are also a growing number of “spaceports” designed for commercial liftoffs and landings. While there are an increasing number of commercial spaceports in the United States, there are also numerous other sites under consideration around the world in locations such as Singapore, the United Arab Emirates, Malaysia, and various sites in Europe.

Height: 43 m

International Communications Satellite Systemsa

Name of system (and HQ location)