ESA started development of communications satellite systems in 1968. Its first telecommunications satellite, the Orbital Test Satellite (OTS), was launched in 1978. OTS technology opened the European market both for broadcasting to cable feeds and for direct-to-home television.
Orbital Test Satellite (OTS)
OTS was used for more than thirteen years by ESA, Eutelsat and European national PTTs. It provided:
OTS was the first three-axis-stabilised Ku-band satellite ever, and its design has inspired the conception of almost 30 other satellites in Europe alone. Its successors, the ECS and Marecs series of satellites, consolidated Europe's position in communications satellite technology andmanufacturing.
Four European Communications Satellites (ECS) were built and launched by ESA between 1983 and 1988 for exploitation by Eutelsat. Three are still in service. Each ECS carries ten active Ku-band transponders, covering the whole European continent for cable television, trunk telephony, specialised services and Eurovision transmissions.
European Communications Satellites (ECS)
Two Marecs satellites were designed by ESA to provide communications between mobile stations, and especially ships at sea. Both Marecs satellites, launched in 1981 and 1984, were leased for operations to Inmarsat and are still in service today. Their L-band payloads, with global coverage, can handle around 50 telephone circuits.
More recently, ESA's Olympus satellite, launched in 1989, has redefined the leading edge of advanced telecommunications services. The satellite carried four payloads providing:
A major event during Olympus's lifetime was the test campaign of inter-orbit communication between it and the Eureca platform, conducted between August 1992 and April 1993. This experimentation constituted a European 'première' in terms of data-relay links between two satellites, one in low earth orbit (Eureca) and one in geostationary orbit (Olympus).
Olympus's experimental mission was concluded in 1993 when the satellite ran out of fuel.
Another major event of recent years was the start of a new programme called 'ARTES' (Advanced Research in Telecommunications Systems), which has taken over from the previous PSDE and ASTP programmes. Several elements of the programme have already been started and are now running at full speed. They include:
Most recently, Element 9: Global Navigation Satellite System, which concerns the development of an overlay system for the present GPS/GLONASS systems and later the development of the civilian successor to these, was approved.
ESA's space telecommunications programme has two basic objectives:
With regard to the first objective, with the trend towards de-regulation within the Member States, and the trade policy of the European Union leading towards procurements that are fully open to worldwide competition, the need for a strong and competitive space industry within Europe has become a question of survival.
As to the second objective, this needs to be addressed in a variety of ways, including maintaining close relationships with operating entities to assess their future needs and carrying out pilot missions in order to continue to prove the benefits and capabilities of satellite communications.
The overall programme, proposed by ESA for the rest of the decade and beyond, contains, on the one hand, a number of specific initiatives directly related to missions seen as keys to the promotion of future systems and, on the other, more general development activities in support of a strong expansion of the present market share that European industry should capture.
Thus, in line with the general worldwide evolution of networks, five areas are being proposed for European industrial initiatives:
In addition to the mission-specific projects, a general set of market-driven developments must be foreseen in parallel to support industry in maintaining a state-of-the-art position in all critical areas of space communications, with the view to capturing a higher share of today s, and tomorrow s, World market.
The future Universal Mobile Telecommunication Systems (UMTS) will expand the range of services offered by the first-generation mobile system, which are limited to voice telephony and low-speed data services. UMTS will offer new services, such as interactive videophones and remote database querying, with data rates of up to 2 Mbit/s, and will provide seamless integration of both terrestrial and satellite (S-UMTS) components of the network, the latter allowing a wide roaming capability into areas beyond the reach of terrestrial systems. Both the terrestrial and satellite components of UMTS will operate in the 2 GHz band.
In order to implement S-UMTS, significant new developments are necessary, particularly in the areas of transmission, networking, satellite active antennas, on-board digital processing, and compact lightweight user equipment.
Space communication will play an integral role in the development of a global information infrastructure, allowing video, audio and data to travel without borders and restrictions. Satellites are a key element for the intercontinental traffic, as well as direct connection to users, bypassing terrestrial means. Already today, satellites offer wide-area coverage and instantaneous availability. In the future, they will also need to provide significantly higher capacity at lower cost. For these purposes, the key innovation is On-Board Processing (OBP), which the Agency has been developing for several years.
In 1994, a first end-to-end laboratory model was successfully tested and Step 1 of the OBP Programme was subsequently initiated. This project is aimed at the development of the core elements of a high-capacity processing system for on-demand communications between small 20/30 GHz user terminals.
An obvious follow-up to these developments should be an operational European OBP system that would be introduced by industry and potential operators, covering Greater Europe and adjacent regions and operationally compatible with similar systems deployed over other continents. ESA supports the launch of such an operational service as a partnership programme, under which the Agency would fund some of the development costs and assist in setting up the initial phase. Operators would exploit the system and thereafter guarantee the continuing availability of the overall infrastructure.
Navigation represents the first step towards integrated traffic-management systems. Its primary objective is to provide signals enabling instantaneous determination of the position of the user, in most cases a mobile. The position information can then be exploited to perform specific functions such as navigation and/or surveillance, which in turn can be used to provide even more elaborate services.
Satellite navigation is based at present on the US Navstar GPS infrastructure (Global Positioning System) and the Russian equivalent GLONASS (Global Navigation Satellite System). An evolution of the current systems, known as the Global Navigation Satellite System (GNSS), will provide an overlay function and supplementary services to those provided by GPS/GLONASS.
Europe will be present in the definition, implementation and control of the various elements of this GNSS system, which will be superimposed on GPS and GLONASS, these two networks being solely under American and Russian military control, respectively. In this context an important initiative has been taken by ESA, the Commission of the European Union, and Eurocontrol to cooperate in the deployment of a European overlay leading to operational services. The formal steps for implementation of this programme are well advanced, and a start is planned by end-1995.
Although navigation and automatic surveillance for air traffic represent a prime application and have the most demanding requirements to date, several other user communities have been established covering maritime, land mobiles and special applications. The area of land mobiles especially has great potential in terms of the volume of likely users: route optimisation, fleet management and driver assistance are just three examples of what is currently being developed.
A further step will be the development of a system under civilian control tailored to the long-term needs of civil user communities and designed for improved navigation performance, whilst still retaining GPS/GLONASS backwards compatibility. The new system will have to be designed to serve the needs of civil users in the time frame 2005 2020. Preparatory activities aimed at the definition of this system have already been initiated.
Archimedes represents a good example of the innovation that should be introduced into the Agency's method of working to stimulate partnerships with industry. Here, ESA would support a European industry initiative that would deploy an operational system of up to six non-geostationary satellites. The spacecraft, in highly inclined elliptical orbits, would serve Europe, North America and the Far East, providing high-elevation, line-of-sight signals to mobile users in the upper-latitude regions, thereby assuring high-quality, uninterrupted services.
The network would be tailored to the requirements of the road transport of the future and would provide:
It is expected that an operational service could be established by the year 2000.
The programme proposed by ESA would provide a structured framework of technical support and involve the following steps:
A data-relay network is an essential component of any modern space infrastructure. Real-time, uninterrupted communications links between orbiting spacecraft and the ground can only be realistically provided by relay satellites. They will, however, be crucial to, for instance, the efficient utilisation of the next generations of earth-observation and surveillance satellites, allowing immediate access to data and the necessary rapid response. Communication with manned vehicles will, of course, also need continuous relay services in order to operate safely and efficiently. Coming generations of LEO communication constellations will also greatly benefit from real-time command and control via a geostationary network.
The United States currently operates the TDRS system and will improve it with a new generation of satellites. Japan is also planning to deploy a data-relay system at the end of the decade and has already started development of a precursor, called Comets , which will provide a pre-operational capacity.
Provision of an independent European data-relay system will be strategically important for ESA's Member States by the year 2000, and this network therefore needs to be coordinated with such organisations as the Western European Union (WEU), involved in surveillance activities.
The European DRS system will consist of two relay satellites separated in orbit so that data can be relayed from vehicles anywhere in low earth orbit, directly to ground stations located over a wide expanse of Western Europe. The first of these satellites, called 'Artemis', is currently in the final development stage and will be launched at the beginning of 1998 to provide - in addition to an advanced regional land mobile service - data-relay services at S-band, Ka-band and optical frequencies. Approximately three years after the launch of Artemis, a second satellite should be launched to offer a full data-relay service around the globe.
A systematic programme, involving a wide spectrum of system analyses and equipment qualifications, will be funded to support European industry in obtaining its proper share of the global market for communications satellites. This development effort will cover the space segment, earth segment (ground stations/terminals) and services domains.