Spacebus is a satellite bus produced at the Cannes Mandelieu Space Center in France by Thales Alenia Space. Spacebuses are typically used for geostationary communications satellites, and seventy-four have been launched since development started in the 1980s. Spacebus was originally produced by Aérospatiale and later passed to Alcatel Alenia Space. In 2006, it was sold to Thales Group as Thales Alenia Space. The first Spacebus satellite, Arabsat-1A, was launched in 1985. Since then, seventy-four have been launched, with one more completed, and six outstanding orders. The launch of the 50th Spacebus satellite, Star One C1, occurred in November 2007. It was a Spacebus 3000B3, launched by an Ariane 5 rocket flying from the Guiana Space Centre in Kourou, French Guiana. Several variants have been built: the early Spacebus 100 and Spacebus 300; followed by the Spacebus 2000, optimised for launch on the Ariane 4 carrier rocket; and the subsequent modular Spacebus 3000 and 4000 series, designed for use with the Ariane 5 rocket.
History Aérospatiale had produced a number of satellites, including Symphonie, with the German company Messerschmitt. On 9 December 1983, the two companies signed the Franco-German Spacebus Agreement. The Spacebus designation was first applied to satellites which were under construction by Aérospatiale when the programme started. These included three satellites for Arabsat, which became the Spacebus 100 series, and five further satellites: two for Deutsche Bundespost, two for TéléDiffusion de France, and the Swedish Space Corporation's Tele-X, which became the Spacebus 300 series. Later series' names were followed by a number indicating the approximate mass of the bus in kilograms. Spacebus designations were not retroactively applied to previously launched satellites.
Architecture
Spacebus satellites consist of a satellite bus, which provides power, propulsion, and other subsystems necessary for the satellite's operation, and a payload which is customisable according to the customer's requirements. The bus was designed to be adaptable to perform various missions; however, as of 2009, only communications satellites have been ordered. It was also designed to be adaptable when the capacity of launch systems increased. The bus is made of carbon fibre with a composite honeycomb structure. It contains fuel tanks, equipment to interface with a carrier rocket, and other critical systems. External panels contain equipment such as solar panels, payload, and engine. The payload, developed separately from the bus, takes up three panels. Once it has been outfitted with transponders or other equipment, it is transported to Cannes-Mandelieu, where it is integrated onto the bus. The satellites are powered by rigid solar panels. Several configurations are used depending on the amount of power the satellite requires. Batteries to store this power are produced by the Belgian company ETCA. Early satellites used nickel-hydrogen batteries, while later spacecraft use lithium-ion batteries. Spacebus satellites use bipropellant, liquid-fuelled chemical engines to achieve orbit and subsequently perform station-keeping. Electric propulsion was used on the Stentor and Astra 1K satellites, both of which were subsequently involved in launch failures. Spacebus Neo will be an electric propulsion satellite. A three-axis stabilisation system is used for attitude control.
Models Spacebus satellites are compatible with a large number of carrier rockets, particularly the Ariane family. As the Ariane's performance has increased, the satellites' capacities have increased accordingly.
Spacebus 100
Three Spacebus 100 satellites were produced for Arabsat to serve the 22 members of the Arab League. One of the solar panels on the first satellite, Arabsat-1A, failed to deploy, resulting in reduced power. This, combined with gyroscope issues, caused it to spend most of its operational lifespan as a reserve satellite.
Spacebus 300 Five direct-to-home television satellites were built using the Spacebus 300 bus, which provided 4.3 kilowatts (5.8 hp) of power.
Spacebus 2000
The Spacebus 2000 series was developed to use additional capacity provided by the Ariane 4. Its solar panels generated 3.5 kilowatts (4.7 hp).
Spacebus 3000 The Spacebus 3000 was introduced around the time the Ariane 5 entered service. Spacebus 3000 satellites have masses from 2 to 6 tonnes (2.0 to 5.9 long tons; 2.2 to 6.6 short tons) and produce between 5 and 16 kW. Increasingly larger payload fairings allowed larger spacecraft to be produced. In 1991, Aérospatiale, Alenia and Space Systems/Loral joined to form the Satellite Alliance. The first version of the Spacebus 3000 was the Spacebus 3000A, originally developed for Arabsat. They were also ordered by Shin Satellite of Thailand and China's Sino Satellite Communications Company. Twelve 3000B2 satellites were ordered, five of them by Eutelsat for their W Series, one of which later became Eutelsat 28A. A sixth order from Eutelsat was for Eutelsat 8 West A. Nordic Satellite AB, a Scandinavian company that later became SES Sirius, ordered Sirius 2, a replacement for the Spacebus 300-based TeleX satellite. Spanish satellite operator Hispasat ordered two satellites, and Arabsat ordered one satellite, Arabsat-3A. The final two were ordered by the German Bundeswehr and were launched on 1 October 2009, and in May 2010, respectively. Nine B3 satellites were ordered, three for Eutelsat, two for Star One of Brazil, GE-12 for GE Americom, Turksat 2A for Turksat, and the Stentor experimental communications satellite for CNES. Stentor was lost in a launch failure on the maiden flight of the Ariane 5ECA. Galaxy 17 was successfully launched in 2007 for Intelsat.
Spacebus 4000
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