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 also provides a multidisciplinary approach that includes technical, operational, economic, regulatory, and market perspectives. These are key areas whereby applications satellite share a great deal. This 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 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 technology technologies and on a quite parallel basis.These 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 ties to applications satellites. Clearly the design and engineering of the spacecraft busses 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 reference work that addresses all aspects of application satellites from A to Z. This handbook thus seeks to address all aspects of the field. It 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.

The serious consideration of the provision of satellite communications from space dates from 1945 when the first technical descriptions were written with regard to launching a spacecraft into geosynchronous orbit and the design of space stations as extraterrestrial radio relays was specifically outlined. In the historical section that follows, however, it becomes clear that the idea or concept had been around many years, indeed centuries before. The 1945 article, however, described the possible delivery of telecommunications services from space and presented detailed calculations as to how this might efficiently be done from a special orbit known as the geosynchronous (or sometimes the geostationary) orbit (Clarke 1945). The use of radio waves for long-distance communications up until the 1960s was limited to microwave relay between towers or the use of shortwave or high-frequency (HF) transmissions that were, in effect, bounced off of the ionosphere. This latter technique was quite limited in transmission throughput and unreliable because the ionosphere was subject to distortions largely due to solar radiation and the so-called solar wind and solar storms. Launch technology that could place satellites in orbit came into being in the late 1950s.

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 that 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 the 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 with 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. This systems control and oversight of satellite orbits involves not only the technical ability to launch and maintain the orbit, but also the ability to attain the proper legal authority at the national and international level to transmit and/or receive radio signal from these orbits. This regulatory process means a number of specific steps associated with registering for the allocated frequencies from the International Telecommunication Union 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 pre-coordination 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 Chap. 3, “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 micro-terminals) 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 Chap. 3 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 designed to interface directly with users at localized office facilities or even small office/home office (SoHo) VSATs or micro-terminals. 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, these transmissions were quite costly and limited by the modest capacity of the first commercial communications satellites. The evolution of satellite technology and development of satellite aggregators such as Brightstar, World Communications, Bonneville, IDB, Keystone, and Globecast, allowed costs of satellite television to decrease sharply. The development of full-time, annualized satellite transponder charges – as opposed to per minute fees – were 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 – allows 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, as well as 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.

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.

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 the 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 radiolinks 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.

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 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 so-called non-intelligent 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:Multi-beam 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 multi-beam 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 multi-beam antennas with multiple feed systems)Deployable antennas (particularly for achieving more highly focused beams and support much high-gain multi-beam 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, progresses to Yagi-Uda antennas, and then on to high-gain parabolic reflector antennas that are the most commonly used in satellite communications 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 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, 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 (Pelton 2005; Also see Iida et al. 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 – manned, unmanned, and planetary bodies – will evolve the need for improved space communications systems. Clearly foreseeable technologies suggest that several 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; (d) Convergence between the various satellite applications markets – both in terms of technology and structural integration; (e) Constraints in orbital configurations; (f) Orbital debris; and even (g) Growth of human activities in outer space may prove to be significant shapers of the growth of satellite systems in the next 20–30 years (Pelton 2005; Iida et al. 2003).

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., US, Russian Federation, China, India, Europe, 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 organization, 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 spacecraft 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.1The 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.

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 telecommunications 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 radionavigation 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 (GNSS) 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.As of 2012, the Navstar Global Positioning System (GPS) of the United States and the Global Navigation Satellite System (GLONASS) of the Russian Federation are the only 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 People’s Republic of China has decided to expand its regional BeiDou/Compass navigation system into a complete global navigation system by 2015 although, with 13 satellites in orbit, it already has limited global coverage. 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 from 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 at 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 the 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 onboard the Landsat series of satellites. Handheld imagery of the Earth has been continually acquired during both USA and USSR/Russian space station and Space Shuttle programs, and represents a rich dataset that complements both historical and current unmanned sensor data for terrestrial studies. This 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 response. 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.

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, 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 down loaded 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 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.

The main objective of this chapter is to focus on the digital preprocessing and data reduction techniques as applied to remotely sensed data for the purpose of extracting useful Earth resources information. The image processing and post-processing 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

The main objective of this chapter is to focus on the digital image processing, post-processing, and data integration techniques as applied to remotely sensed data for the purpose of extracting useful earth resources information. 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, Numerical Weather Prediction (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 (GIS), 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.

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, for ever 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. The first systems were pioneered by the United States 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 and allow 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 and 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.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 entirely as governmental services.Despite discussions and analysis of how meteorological services might transition to commercial service providers within the United States, the provision of space-based meteorological services seems likely to remain as essentially a “public good” and not commercialized in any space faring 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 commercialized.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 United States 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 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 United States 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 US. 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 United States 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.

EUMETSAT, the European Organisation for the Exploitation of Meteorological Satellites, operates a range of satellite programs, among them the Meteosat series of geostationary satellites which has provided continuity of coverage over Europe and Africa since 1977. Its current operational geostationary services are provided by the Meteosat Second Generation (MSG), consisting of the primary satellite, the Meteosat-9, the back-up and Rapid Scanning Service Meteosat-8, as well as the older generation Meteosat-7 satellite positioned over the Indian Ocean. It works closely in partnership with the European Space Agency and with NOAA in its programs. As a user-driven organization it places great emphasis on developing additional value from its products by sophisticated systems for processing of the satellite data, centrally at its headquarters in Darmstadt, and through a distributed network of Satellite Applications Facilities in its Member States. A successor program to the MSG, the Meteosat Third Generation, has been approved and will ensure coverage out to 2040.

The oldest and most extensive meteorological satellite systems are those of the United States 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 United States are in various manners linked together and share data. This international coordination of meteorological data is accomplished through the World Weather Watch (WWW) program 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 United States 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.

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 as well as 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 deployment of solar arrays, antennas, and other systems that must be unfolded 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. The following text discusses all of these strategies for coping with and minimizing risk for the satellite applications industry.

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 communications 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 down links while other are more interactive with up and down links.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.Down-linked 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 down-linked 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 systems 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 type 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.

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 6,300 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 sub-catalog 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 non-trackable 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 run-away 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.

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.

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.