Tim Furniss/LONDON
MATRA MARCONI SPACE (MMS) has introduced a new spacecraft bus, the Eurostar 3000, designed to play a leading role in the rapidly emerging Global Information Infrastructure (GII), delivering broadband multimedia, advanced hand-held telephony, and direct-to-home broadcasting services from geostationary orbit (GEO).
MMS will be offering the Eurostar in Europe in competition with Aerospatiale's Spacebus 3000. Internationally, the US leader, the Hughes HS-601 High Power, will be the main rival. Other competitors are Lockheed Martin's Astro Space new Satcom 2100 and Space Systems/Loral FS-1300 spacecraft platforms.
Of the 118 GEO communications satellites active in April 1996, 18 were HS-601s and 11 FS-1300s. There were six earlier-generation Spacebus 2000s and six Eurostar 2000s also in GEO, according to a study by US research company the Teal Group. Seven original Spacebus models and four Eurostar 1000s are also in orbit. The 23 other HS model types demonstrate Hughes' lead. There are also 18 earlier Lockheed Satcom models, including four of the Satcom 7000 series.
CRUCIAL COMMONALITY
The key to modern satellite manufacturing lies in maintaining a high level of commonality across missions, enabling a "configured-to- order" service for customers, establishing the almost off-the-shelf approach, which has been achieved with the HS-601 fleet.
To introduce the Eurostar 3000, which will have almost double (at 1,000kg) the maximum payload mass of the 2000 module, MMS plans to establish a GEO communications satellite system, called the Euro-African Satellite Telecommunications (EAST), for Africa, Europe and the Middle East. This will provide national or regional telecommunications operators with capacity for fixed and mobile services to complement their cellular-telephone networks and existing telecommunications infrastructure.
The one-satellite EAST-system (with a ground spare) network control and gateways for national operators, will be particularly suited to developing countries, particularly providing mobile telephone services offered at 8¢/min. Matra Communication, another subsidiary of MMS holding company Groupe Lagardere, which is a major supplier to the cellular market, intends to supply the handsets.
The EAST will have a capacity of 6,000 mobile circuits and 200,000 fixed circuits, supporting over 1 million subscribers and will enter service in 2000. The potential, 10 million-customer base and estimated $750 million investment will be shared by Matra companies and operators.
New standards for supporting satellites have been established for the emerging GII market - especially the need to provide high-power transmissions to very small terminals, such as mobile telephones, on the Earth. With the GII, customers are also emphasising the necessity to provide a better return on investment in communications revenue; the need for a more favourable payload-to-spacecraft weight ratio; and the requirement for a reduction in launch costs. MMS believes that the Eurostar 3000 will meet these new high standards.
The 3000 is the latest of a range of Eurostar spacecraft which were originally introduced in 1983 by the then-Satcom International consortium of British Aerospace and Matra. It is derived from the three-axis-stabilised ECS satellite bus, the first of which was launched in 1978 and was followed by six other craft.
The first Eurostar 1000 satellites to be ordered were four Inmarsat 2s, in 1985. The first Eurostar 2000s were four Telecom 2s, the first of which was ordered in 1988. Twenty-two Eurostars have been ordered, ten of which have accumulated 35 years of operations in orbit (see box), starting with the Inmarsat 2F1 in October 1990, with a 99.998% mission-service reliability. Of the 12 Eurostar 2000s under development, three are being built for prime contractor Alcatel Espace for the Worldstar project - the Afristar, Asiastar and Caribstar.
This compares with 23 Aerospatiale Spacebus craft, of which 11 have been launched, including three Spacebus 1000s and eight 2000 models. Two of these were lost in Ariane launch failures. The 12 in production or ready for launch are two 2000s and eight 3000s. The last Spacebus was ordered in 1995, whereas nine MMS Eurostars have been ordered in the last nine months.
There are no orders yet for the MMS 3000 model, however, so theoretically Aerospatiale leads in this numerical classification. The upgraded Eurostar 3000 avionics have already been selected, however, for the Government-funded French communications-technology satellite, the Stentor, to be launched in 2000.
The development of the Eurostar 3000 has been part of MMS' continuing research-and-development programme to incorporate well validated and proven technologies in spacecraft, allowing the company to maintain state-of-the-art status, while maximising the heritage and commonality between programmes. Developments of specific hardware for the 3000 began in 1994, including complete structural test and avionics qualification models.
The Eurostar 3000 can weigh from 3,400kg to a maximum launch mass of 4,600kg, compared with the 1,000kg-1,600kg/3,400kg ranges of the 1000 and 2000 series, respectively. Maximum spacecraft power has graduated from the 1-2kW on the 1000 series, and the 2-7kW on the 2000, to a new range of 5kW to a potential 16kW offered by the Eurostar 3000.
Maximum payload mass has increased to 1,000kg on the 3000 from 200kg and 550kg on the earlier models, partly through the use of emerging lightweight materials, as well as the increase in size. Depending on customer preference, and to reduce launch mass and payload-to-weight ratio, the 3000 can be equipped with a complementary flight-proven plasma propulsion system for orbit and attitude control, in addition to the standard chemical bi-propellant systems. This can save propellant weight on the standard systems, which can be placed on to the payload.
SPACECRAFT GUARANTEED
The 3000 - and other future Eurostars - will be designed to require minimal ground support, limited to normal working hours, possibly halving operational control costs. The spacecraft is guaranteed with 30 days operational autonomy and 72h mission continuation without ground intervention.
The Eurostar was the first commercial communications-satellite platform to use an all-digital data handling and attitude control avionics architecture. A unique solar-sailing concept, using parts of the electricity-generating solar panels, has been demonstrated, to provide attitude pointing better than achieved with standard thruster-based techniques.
Source: Flight International
