Chapter 5
Space Communication and Observation System of Systems 1
The following chapter aims to illustrate, as simply as possible, how the notion of system of systems is consubstantial to the space systems and the daily services provided by these satellites: telecommunication-television broadcasting, guidance-navigation-dating, but also meteorology-oceanography-geography, which rely on Earth observation abilities, some of which are dedicated to the military intelligence of certain countries.
5.1. The dual context of omnipresent information and the commoditization of space
The increasing need for telecommunication services available in all places and at all times, as well as multimedia distribution, localization and navigation, converters, telecourses, telemedicine, etc., drives the development of new communication systems essentially based on wireless technologies. Concurrently, the growing interest in making such services available within regions where the telecommunication infrastructures are very limited is an answer to the modern problem of digital divide.
This is how the satellite communication and global navigation systems provide access to strategic technologies which have an important economic and social impact in the following fields: data transmission for air, rail and sea transports, natural disaster forecasting, humanitarian aid, crisis management, etc. These fields of application require the transfer of images, videos, voices, and the performance in terms of robustness, transmission delay and security must be accordingly high.
Moreover, the impact of the new information and communication technologies has created a new paradigm which elevates the information and communication system to the level of corporate strategy. No longer a simple infrastructure of interconnection and service networks, doubled with low-level data transfer services, the so-called information and communication systems have gained a real strategic value. This concerns all the various fields of application, civil and military.
The United States have sought to profit from this new paradigm in the field of defense, by adopting the so-called Information Warfare doctrine, based on the notion of information superiority (sometimes called full information dominance). The underlying idea is that conflicts, whether armed or not, are for the most part fought and won on the battlefield of information. The documents Vision 2010 and Vision 2020 focus the American military strategy (but also the military strategy of NATO and of the vast majority of countries) and the control of information flows. Initially approved in the second half of the 1990s, and despite being criticized after September 11 and the Iraqi crisis which started in 2003, these documents are still topical and represent the logical progression of the technical objectives defined by William Perry as early as 1978:
“to be able to see all high-value targets on the battlefield at any time; to be able to make a direct hit on any targets we can see; and to be able to destroy any target we can hit.”
The path to meeting these objectives goes through the creation of the system known as C4ISR (Command, Control, Communication, Computers, Intelligent, Surveillance, Reconnaissance), which regroups the data and puts them at the commanding authorities’ disposition. In its broadest definition, this system includes the decision components, as well as the components of the weapon systems, providing them with adequate guidance and navigation. In theory, its extensive use gives access to full connectivity and in turn to the establishment of an unbroken situation awareness from one end of the chain of command to the other, and helps achieve more precise targeting and increase the theater’s depth. Let us look at a concrete example: statistically, during World War II 4,500 bombers would each have to drop two tons of bombs in order to destroy a target the size of a house. Today, it would only take a few cruise missiles launched several hundred miles away. The aforementioned system, which obviously fully pertains to the class of systems of systems, as has been mentioned in Chapter 1, helps look at military operations as OODA loops, consisting of four steps: observe, orient, decide and act. The enemy is first observed, then this information helps the commanding authorities orient their choices; the final decision is reached through a decision making process, after which the action finally happens (whether it be further observation to complete the information, or the actual fight). The result is studied, and another loop begins. The goal is obviously to chain OODA loops faster than the enemy, so as to keep the upper hand.
From a technical standpoint, three things can help improve those loops’ speed and performance:
– Bandwidth: during the first Gulf War in 1991, the coalition had a bandwidth of 100 Mb/s. In Afghanistan in 2001, capacities went up to 800 Mb/s, they reached 7 Gb/s in Iraq in 2003, and bandwidths in the range of 16 Gb/s are expected in 2010.
– Precision of observation: the first goal is to distinguish details as small as possible so as to be able to not only detect, but also recognize possible targets and threats (for example, being able to tell apart a bus and an armored personnel carrier), and in some cases identify them (for example, distinguish one type of vehicle from another); the second goal is the ability to localize fixed and mobile objects within a reference three-dimensional space, with metric accuracy, either to improve the comprehension of the observed scenes, or to optimize the resulting geographical data and avoid, for example, targeting errors and the associated “collateral damages”.
– A comprehensive view: intelligence must be as extensive and detailed as possible, the objective being constant real-time surveillance, which entails demands both in spatial and temporal coverage.
All three requirements call on the use of space: telecommunication, localization and remote sensing satellites are therefore tools inherent to the very nature of this revolution of military affairs.
5.2. The technical view: an interconnection of ground-based and space-borne systems
A space system is by nature a distributed system whose orbital segment, which can be composed of several satellites, is a component which cannot, in itself, fulfill a mission.
Even if it only plays a fleeting part in the satellite’s life, the launching infrastructure itself can be apprehended as a system of systems composed of a “spaceport”, to use the appellation of the Kourou base, of the launcher itself, and also of the trajectography and telemetry centers scattered around the surface of the globe. These tools may even be mobile, such as the French Minister of Defense’s Monge naval building, in order to adapt to specific trajectories.
In a steady state, a space system includes a minima, besides the orbital segment, a ground control or station keeping segment, and a user ground segment. If the orbital segment is the most visible and therefore most critical, the control segment is just as essential for the maintenance of the function, and can if need be extend the life of the space-borne component, by guiding the satellites on particular orbits, for example. Lastly, the user ground segment can be located in several places and made up of several interconnected systems.
5.2.1. Telecommunication and navigation satellite systems
In order of complexity, we first find the geostationary telecommunication satellites, which are, in (excessively?) broad outline, elevated cell towers (22 400 miles high!). Then come the radio navigation and communication systems, which use low earth orbiting satellite constellations. These capacities require a global approach of the constellation, which is constructed through increments: constantly, new satellites are being purchased, other satellites are in use, and some satellites are reaching their end-of-life, all spreading over several technological generations.
With regard to telecommunications, the needs, civil as well as military, are constantly increasing: as an example, the ambition of the United States in the military field is to multiply bandwidth by ten in years to come. This is achieved through the sharing of resources between civilians and military forces, and an ever growing migration towards civil resources: whereas 75% of the war theatre telecommunications had transited through military satellites during the First Gulf War, only 40% did so during the war in Kosovo and 20% during the Second Gulf War. Such sharing of resources demonstrates the criticality of a global approach where the use of systems is mostly about the management of the availability and capacity of a service which uses various systems, in space and on the ground.
It should be noted that the civil or military space telecommunications only represent one of the components of the telecommunication system: the ground segments include fixed earth stations, and in the military field, mobile earth and sea stations. The interconnection of the various networks ensures the function of global communication. In the military field, national authorities and the authorities deployed on warfare theaters can therefore command the troops regardless of the distance, discarding the local infrastructures.
This all seems normal to us, since we use that function daily. It calls on physical interconnections, constant signal exchanges following various protocols, interoperability on various levels, security software to guarantee the data’s integrity, and the constant upgrading of some of its components. Incidentally, we should remember that, on the one hand, the life of any satellite is subject to the laws of physics, and therefore not is eternal, and on the other hand the constant need for improved performances requires technological upgrades to be performed on the various equipment, which is not easily achievable with space components. The configuration management of the global technical architecture is all the more critical, as well as the management of its obsolescence with regard to the expected evolutions in service quality.
Localization by satellite, at the base of the navigation function so widely used in daily life and in military operations, follows this scientific principle: a cellular phone equipped with a specific receiver can be localized within a universal reference system, based on its distance from at least four satellites in simultaneous visibility; its speed can be calculated via the measurement of the Doppler effect of the frequency emitted by these four satellites. Therefore, to localize anything anywhere on the planet, one only needs to have access, on each point, to a minimum of four satellites, which implies spatial coverage via a satellite constellation, as well as a signal reception system and a minimum calculation capacity to deduce the necessary information from the compiled data. The American GPS (global positioning system), and the Russian GLONASS (in English, global navigation satellite system) have thus been designed to provide millions of civil and military users with information on their position at any time, anywhere on the globe. These systems also transmit a precise time reference used in many applications, for example to synchronize cell phones with the communication networks’ base stations, or to track the position of a mobile user.
Nowadays, the American GPS constellation has the monopoly on that service. Its general architecture consists of three major segments: the space segment, the control segment, and the user segment, both of which are on the ground. The space segment is composed of 24 satellites arranged so that each point of the globe receives signals from at least six of them almost constantly. The control segment is composed of five ground stations scattered over the world: each of the constellation’s satellites completes one orbit of the Earth in 12 hours and carries a precise clock which enables the exact dating of any transmitted signal. The user segment is represented by receivers, which can be carried manually or embedded in vehicles. The standard localization precision is in the range of 100 m, and can be corrected by a factor of 100 by a receiver whose fixed position is known. Nowadays, more than 100 different types of receivers can be found on the market, with varying sizes.
Ever improved, the GPS system is a major leverage tool for the United States, in particular in times of conflict, insofar as a great many combat and weapon systems use GPS for localization, navigation and synchronization. This is why the European Union has decided to develop the Galileo system, which should be operational around 2013. China and India each have the same objective of acquiring an independent global navigation system.
The example of GPS navigation and its connected services, whether it be traffic maps in our cars or distress beacons for adventurers, is the archetype of the interconnection of numerous systems scattered geographically in space and on the ground, which were manufactured separately and can be used independently, and provide new services when grouped within the same architecture.
5.2.2. Space-borne remote sensing and observation systems
Those systems gather information, on the globe’s surface and in the atmosphere, and compile the signals within various electromagnetic tapes, often translating them into images. An important characteristic of satellites in charge of transferring images is the ground resolution: nowadays they often achieve a resolution of 1 m. Thus, Ikonos, which was put into orbit by the United States in 2000, provides commercial images with a resolution of 80 cm, and Quickbird, launched in 2001, achieves resolutions of 61 cm. In both cases, private initiatives are encouraged by the United States Government, and the images are at the basis of services provided to users, simultaneously processing space observations and complementary information: we only need think about Google maps, or other services recently accessible via the Internet.
If remote sensing satellites were originally used by the military, in particular to gather intelligence on nuclear powers and guided missiles during the Cold War, and to implement the treaties on arms controls, nowadays those satellites are just as much civil as military, and result in cooperative exchanges of capacity, as we will study in the following paragraphs.
The systemic aspect of space-borne observation and telecommunication became fully apparent during the Kosovo Conflict in 1999: the targets were defined from the fusion of data collected by observation and spy satellites, the missiles sent to destroy said targets were guided by GPS, the results were evaluated by the spaceborne and airborne intelligence network, the command systems, California-based in the case of the United States, were in permanent liaison, and the media coverage was also passing through space systems! Moreover, the space and ground components worked complementarily with airborne systems such as UAVs (unmanned aerial vehicles) and reconnaissance aircrafts, in particular for the collection of intelligence.
The following conflicts, Afghanistan in 2001 and the Second Gulf War in 2003, confirmed those trends. In terms of technical performances, the integration of these various resources within a system of systems, in addition to the technical improvement of the various components, helped drastically shorten the OODA loops, going from about 48 hours in 1999 to 10 mins in 2003.
5.3. Search for functionality and capacity
It should be noted that in the case of telecommunication/broadcasting and radio navigation systems, the user ground segment cannot be dissociated from the service. In the first case, it enables the transmission or reception of information to where the user stands. In the second case, it is the presence of the radio navigation receiver where the user stands which enables precise pinpointing of that user’s location. In both cases, the satellite system only provides a generic capacity, or even part of that capacity, the other part being at the hands of a component acquired by an end-user which might belong to the public at large (antenna and decoders for satellite television, or GPS receiver) and therefore might be acquired in a logic largely independent from the one who presided the contracting or design of the satellite system.
On the other hand, the use of Earth observation satellite systems relies on “centralized” processes, since the end-user will have to file his request for observation with an organization which, if it does not possess the information in its database, will transmit the request after managing the priorities upon programming of the satellite.
However, in order to optimize the system’s performances (see above), the ground segments of control, station keeping and mission, relying on a network of telemetry stations, are scattered on the surface of the globe. These infrastructures, while belonging to different organizations, are “mutualized”.
The global design of a satellite observation system greatly varies depending on the desired capacity. The capacity can notably be described in relation to the following terms: life expectancy, the observable zones and the priorities between said zones, the revolution rate, the quality of images (ground resolution, spectral, radiometric, level of noise, geometric quality, etc.), the nature of the elaborated products (panchromatic, color, stereo couples, etc.), the hours of exposure (heliosynchronous orbit, or not, and if so, the hour of passage over the equator, geosynchronous, etc.), the satellite’s agility (ability to observe everything within a cone around the nominal line of sight, and to rapidly change the line of sight), the incidence of the exposures. These characteristics are strongly dependent on the chosen platform, instrument and orbit. However, the arbitrations are also dependent on the connected infrastructures, notably terrestrial. Besides the ability to insert the space launchers on a given orbit from a given launch area, the ground systems have an impact on the satellite’s programming delay (time between the moment the user asks for an image and the transfer of his demand to the orbital segment), on the information’s age (time between the moment the exposure is taken and the moment it is made available to the user) and therefore on the delay of access to information (time between the moment the image is requested and the moment it is made available to the user). As an example, the ESA is using the stations network ESTRACK, which shares the Kourou (French Guyana) and Kiruna (Sweden) stations with the CNES, which also uses, for systems such as SPOT 5, the stations of Aussaguel (near Toulouse, in France) and Hartebeesthoek (South Africa), in order to optimize station keeping and mission programming. In its transient stage, the CNES also uses the stations of other agencies: Wallop Island (USA) and Poker Flat (Alaska) for NASA, Okinawa and Katsuura (NASDA, Japan), Prince Albert (CCRS, Canada). The vocation of centers such as CNES’s PASO (architecture panel of orbital systems) is to enable the definition of these global architectures. Like the battle-labs mentioned in Part 1, Chapter 1, these centers use simulation tools to optimize the border/grounder compromises, but also the platform/orbit and cost/performance ones.
The GMES project (Global Monitoring for Environment and Security), a joint initiative of the ESA (European Space Agency) and the European Union, is the proof of a strong European desire to federate and rationalize Earth observation activities in Europe. This project consists in a set of thematic services, whose first components should be operational as of 2008, and which will leverage the existing and future infrastructures, but also help develop assets for the collection and distribution of data, and integrate these data within environmental monitoring and prediction systems. It also plans to ensure long-term continuity and the upgrading of the space infrastructures needed for the gathering of said data. Besides providing Europe with a trustful, precise environmental information system, this initiative also contributes to the common policy of security and defense, via dual uses (civil and military) of some spatial resources in particular.
5.4. A logic of exchange on an international scale
It should be noted that in the fields of weather forecasting and oceanography, among others, the observed phenomena can be explained by coupled multi-scaled mechanisms (micro, meso and macro); corollary from that coupling, the forecasts only have a local interest even though they call upon the collection of data on the entire surface of the planet. The need for information on various scales and about mechanisms which are not always discernible from space leads to the use of observation tools in situ just as much as space components. The acquisition of these various components represents a width of investment which no single country can sustain in time. Moreover, scientific and industrial stakes lead countries or regional organizations to finance the constituents of both components. Coordination happens within international organizations (answering to the United Nations). Besides the distribution of requirements between the various components and constituents, and the coordination of schedules so as to assure the permanency, or even the improvement, of performances, the main challenge lies in the ability to exchange data.
The issue is similar in the field of imagery for national defense and security, where resources are sometimes shared with civil resources. In the following paragraphs, we will study the organizations which are created in order to optimize the value chain of the observation and telecommunication system of systems, following that organizational dimension.
5.4.1. The GEOSS program
The GEO (Group on Earth Observations) is an international group launched on a voluntary basis following the calls for action by the 2002 World Summit on Sustainable Development, and the G8 group of the leading industrialized countries. It represents a step towards meeting the goals set by the United Nations Millennium Declaration, furthering the implementation of the obligations linked to the international environmental treaties.
The GEO offers a framework within which partners can develop new projects and coordinate their strategies and their investments. At the end of 2007, the group’s membership included a total of 71 governments as well as the European Commission, and 46 intergovernmental, international and regional organizations as participating organizations. It coordinates efforts within the GEOSS (Global Earth Observation System of Systems) program.
GEOSS’s objective is to become a global Earth observation system, coordinated and maintained through time in order to improve the surveillance of the state of the planet, the comprehension of the processes which govern the Earth and the forecasting of the Earth system’s behavior.
The GEOSS system of systems is a global public infrastructure which must generate environmental data and analyses in near-real-time, for the benefit of a wide range of users and decision makers. Its purpose is to interconnect the existing and future observation systems, whether they be floating buoys monitoring the oceans’ temperature and salinity, meteorological stations and balloons recording air quality and rainwater trends, sonar and radar systems reckoning the fish and bird populations, seismic and GPS stations recording movements in the Earth’s crust, some 60-plus satellites observing the Earth from space, or early warning systems, for example against tsunamis; it must also interconnect numerous numeric models used for various simulations and forecasts. GEOSS seeks the interoperability of all these tools and also aims to reduce costs and promote international cooperation.
Its ambition is to provide information useful to the nine “social benefit areas”: natural disasters, health, energy, climate, freshwater resources, weather forecasting, ecosystems, agriculture and biodiversity. More precisely, the aim is to:
– reduce the loss of property and human lives resulting from natural or human-induced disasters;
– understand the environmental factors which impact health and well-being;
– improve the management of energy resources;
– understand, assess, predict, mitigate and adapt to climatic changes and variability;
– improve the management of freshwater resources through a better understanding of the water cycle;
– improve the weather information, forecast and warning;
– improve the management and the protection of the terrestrial, coastal and marine ecosystems;
– encourage sustainable agriculture and fight against desertification;
– understand, monitor and preserve biodiversity.
In addition to the interoperability of the measuring and calculation tools, the collected data must also be pooled together, insofar as one set of data can be useful to several users, just as one user might need several datasets. On a technical level, this requires, on the one hand, the use of common standards so each existing or future component can communicate with the other systems, and on the other hand the certainty that each user will adhere to the exchange principles of the system of systems, for the data, the metadata and the products. For example, on the level of data and metadata, one challenge is to coordinate the socio-economic variables; in more prosaic terms, a common model of ground elevation, providing a stable, accurate, homogeneous and global geodetic point of reference, is also necessary to efficiently compare the set of observations. Besides these data models, the GEO competent technical groups are also developing a data quality strategy, and implementing better practices relative to the calibration and validation of the sensors and the data.
The standards used within GEOSS are recorded as technical specifications sanctioned by the participants and based on non-proprietary, recognized international standards. Insofar as a certain number of GEOSS’s constitutive systems will ultimately follow their own path, and thereby acquire operational independence, the real demand lies in standardizing the interfaces through which the various systems connect to GEOSS’s other components. Moreover, the descriptions of the components, services and standards are formally recorded in a document managed by GEO’s adequate technical groups.
In addition to this reflection on interconnection standards, GEOSS also provides true collaborative infrastructures, such as sensor networks, which enable communication between geographically scattered sensor platforms. Likewise, a concept of virtual constellation is in development, and will enable the coordination and correlation of the measures provided by the various satellite networks contributing to GEOSS. Lastly, the output data compiled by GEOSS are accessible via a portal, with a view to presenting them to decision makers and the set of users of Earth observations.
One of the objectives of GEOSS in the field of sustainable development is to implement true capacities at the disposal of the international decision makers, which will allow them to manage and protect the natural resources and drive the private sector in the same direction. For example, GEONETCast is a system providing environmental data in near-real-time, from earth, sea, air and space observations, transferred to the users via a network of four communication satellites. The potential users include organizations established in countries with limited access, or no access at all, to high-speed internet. One of the capacity objectives of GEONETCast is therefore to help the users, among whom the ones susceptible to belonging to the decision chain, identify their top priority needs and train themselves to use potentially useful data. Such issues pertain more to governance than to technical and functional demands, even if the demands are obviously essential in reaching the determined capacity objectives.
5.4.2. Necessary governance of the GEOSS program
GEOSS is governed by a plenary consisting of all members and participating organizations, which meets at least once a year at the level of senior officials, and periodically at the ministerial level. An executive committee composed of twelve elected representatives from the five GEO regional caucuses (three for each of the American, European and Asian continents; two for the African continent; one for the Commonwealth of Independent States) pilots the GEO activities in-between plenary sessions. Four co-presidents elected by the members of GEO preside over both the plenary and the executive committee.
The 10-Year Implementation Plan, adopted in February 2005, sets GEOSS’s vision, its scope, its priorities in terms of capacity and techniques, its governance structure. Moreover, it defines 107 objectives to meet within two years, 82 objectives within six years, and 56 objectives within 10 years. Committees and workgroups are created to implement these various points, and define action plans with precise deadlines.
GEOSS is, as stated by its acronym, a true system of systems: the in situ space observation systems, as well as the information systems which transform and transfer the data to decision support systems, will retain their initial missions as well as their own modes of governance. The standardizing elements which we have mentioned in the previous paragraphs will help resolve this conundrum, and their definition as well as their acceptance is part of the governance principles. Moreover, the international GEO group is in negotiation with national and international organizations for the acquisition of a certain number of dedicated radio frequencies, in particular for the transmitting of certain satellite measurements.
If the notion of architecture is frequently brought up, it should be pointed out that it is mainly inscribed within a bottom-up approach, going from the systems to a global capacity. Its principal aim is to insure the programs’ coordination and the implementation of shared standards for the production and sharing of data. On the other hand, there is no engineering infrastructure aimed at a top-down approach, going from the need to the allocation of demands to the constitutive systems. This idea is notably found in the key documents with such assertions as: “The success of GEOSS will depend on data and information providers accepting and implementing a set of interoperability arrangements, including technical specifications for collecting, processing, storing, and disseminating shared data, metadata, and products.”
We should however notice that the set of space systems is not yet thought out as an intrinsic “space component” to which is “collectively” allocated part of the performances expected from the system of systems. To this day, the main limitation is essentially budgetary. It also stems from the implemented governance, which relies on international organizations treating a given issue, weather forecast for example, or regional organizations such as Europe, which contributes to GEOSS via GMES (Global Monitoring for Environment and Security).
5.4.3. Capacity exchanges in the military field
Things are slightly different within the military field, as we are about to see. For example, the American approach to space-borne military intelligence consists of defining the operational capacity of the space component, and achieving it by relying on the possible interactions between satellites; for example by using a communication satellite as the relay of an observation satellite. In Europe, the approach somewhat differs, essentially for historical reasons relative to the recent constitution of the European Union as an entity featuring one common policy and a desire for the common acquisition of systems.
In 1999, during the meeting of the European Council in Helsinki, the European Union decided to achieve autonomous action on the military level, leading to the creation of the European Security and Defense Policy. This ability to quickly deploy military forces capable of leading operations at corps level was achieved from conventional contingents provided by the various countries. But this force must be provided with the means crucial to autonomous action, namely the ability to listen and observe, and more generally to gather intelligence. There is still some way to go, since the intelligence approach is still fundamentally national, even though exchanges between services have been going on for a long time. A real European Intelligence doesn’t yet exist, but one of the first steps in that direction is the sharing of resources which were up till now jealously withheld, namely the satellites and the data they compile.
To this day, the French own the military observation satellite Helios, which provides optical imagery data. The first generation, with the launch of Helios I A in July 1995 and Helios I B in December 1999, was designed in cooperation with Italy and Spain; each of these nations can order images via these satellites for its own benefit. The second generation, with Helios II and a first satellite launched in 2004, followed on from the previous cooperation strategy with the added partnership of Belgium, Greece and Germany, and saw an improvement in image resolution, faster exposures, the addition of infrared capacities and an improvement of the ground stations in order to answer the demands of end-users following the feedback of the previous generation. Germany owns the Sar-Lupe system, a constellation of five satellites, launched between 2006 and 2008, which use synthetic aperture radars and therefore achieve very high resolution. Italy owns the system COSMO-SkyMed, composed of four satellites, the first of which was put into orbit in June 2007, and which also provides high-resolution images through the use of synthetic aperture radars. The bilateral treaties which have been established in recent years regulate the exchanges of images between these countries, so each of them can have, in theory, access to an operational Earth observation capacity at all times, day and night and regardless of the weather, thanks to the complementarity of the various sensors.
The objective is to further those advances, and achieve a common system of space-based imaging: the common operational need has been defined, and the end-of-life of the current systems is planned between 2014 and 2017. Rather than relaunching independent space programs on the level of each nation, we ought to combine each country’s capacity, which is the aim of the future MUSIS system (multinational space-based imaging system), born from the cooperation of six European nations: France, Germany, Belgium, Spain, Greece and Italy.
Besides improving the sensors’ performances, this system will enable a single access to the system’s various space-based imaging components: optical sensors, radar, infrared, hyperspectral. To this day, we cannot program the various satellites through one single tool, but the MUSIS system should give an operator the possibility of programming the satellite the most adapted to his needs from a single ground station, and it should also reduce delays between the programming of a satellite and the acquisition of the image by the authorities. This might be possible through the use of relay satellites, programming and receiving stations located on the field of operations, as well as the sharing of data through the creation of a common image and information database. We are faced with a system of systems logic of capacity, in which we must go much further than the simple juxtaposition of several chains, respectively composed of space and ground segments, and achieve real integration of the ground components providing a common service which optimizes the available space resources.
Moreover, the various space telecommunication systems which have been deployed by certain nations within NATO a priori feature gateways to interoperability, which can enable mutual support and coverage extension.
5.5. Conclusion
Spaceborne telecommunication and observation systems require the implementation of many systems, both in space and on the ground, in order to provide functions of capacity evolving through time. In that way, the definition of systems of systems, such as has been given in Chapter 1, naturally applies.
To further add complexity to the previously discussed space system of systems, and in particular the technical and functional architectures, let us mention DARPA’s (Defense Advanced Research Projects Agency) System F6 program (Future, Fast, Flexible, Fractionated, Free-flying Spacecraft United by Information Exchange) in the United States, which aims at fractioning the traditional monolithic satellites into a cluster of smaller satellites, each weighing under 650 pounds, launched separately but later flying in formation, and interconnected through wireless links, or maybe even capable of physically binding, in order to create a single virtual satellite. Small satellites within the cluster could exchange information and power. The calculation capacity would also be distributed and could potentially be heightened through the addition of new modules. The global objective is to reduce the risks of destruction and increase the robustness of the functions carried out by space systems, while adding flexibility and evolutionary capacities so as to prevent obsolescence.
5.6. Bibliography
[BLA 05] BLAMONT J., ESPACE et défense, Presentation during the colloquim organized by the Académie des technologies in honor of Mr Hubert Curien, Paris, September 15, 2005.
[GEO 05a] GEOSS, The Global Earth Observation System of Systems (GEOSS) 10-Year Implementation Plan, ESA Publications Division, The Netherlands, Bruce Battrick (ed.), February 2005.
[GEO 05b] GEOSS, The Global Earth Observation System of Systems (GEOSS) 10-Year Implementation Plan Reference Document, ESA Publications Division, The Netherlands, Bruce Battrick (ed.), February 2005.
[KNAST 07] KHALSA S.J.S., NATIVI S., AHEM T., SHIBASAKI R., THOMAS D., The Global Earth Observation System of Systems (GEOSS) Interoperability Process Pilot Project, IGARSS, 2007.
[MinDef] MINISTÉRE DE LA DÉFENSE, portal accessible at: http://defense.gouv.fr.
[MUS 08] MUSQUÉRE A., “La DARPA veut fractionner les satellites”, Air & Cosmos, n° 2116, March 14, 2008.
[OM 08] OBAIDAT M.S., MARCHESE M., “Recent advances in global navigation and communication satellite systems”, IEEE Systems Journal, vol. 2,n° 1,2008.
1 Chapter written by Frédéric Pradeilles and Dominique LUZEAUX.