Alphabus
Encyclopedia
Alphabus is the name given to a family of heavy geostationary communications satellites.

Alphabus is developed by a joint venture between Thales Alenia Space
Thales Alenia Space
Thales Alenia Space is an aerospace company born after the Thales Group bought the participation of Alcatel in the two joint-ventures between Alcatel and Finmeccanica, Alcatel Alenia Space and Telespazio.-History:...

 and EADS Astrium Satellites in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, with support of the Centre national d'études spatiales (CNES
CNES
The is the French government space agency . Established under President Charles de Gaulle in 1961, its headquarters are located in central Paris and it is under the supervision of the French Ministries of Defence and Research...

), the french space agency and the European Space Agency
European Space Agency
The European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...

 (ESA).

The Alphabus platform is designed for communications satellites with payload power in the range 12-18 kW. Satellites based on Alphabus will have a launch mass in the range 6 to 8 tonnes, 40 % more than the most powerful Spacebus
Spacebus
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 fifty-two have been launched since development started in the 1980s. Spacebus was originally produced by...

 4000.

In order to cover the mission range in an optimised way, the platform product line includes several options such as electric propulsion, and features scalable resources (solar array, radiators for thermal dissipation, etc). The platform will be able to accommodate up to 190 high power transponders and large antenna farms, and will have a significant growth potential (22 kW payload power and 9 tonnes launch mass for the extended range).

Product line

Development of the new satellite, made in cooperation between the two large European satellite manufacturers, take into account the best lessons learned from previous incarnations of similar satellites: the Spacebus
Spacebus
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 fifty-two have been launched since development started in the 1980s. Spacebus was originally produced by...

 and Eurostar families, respectively from Thales Alenia Space
Thales Alenia Space
Thales Alenia Space is an aerospace company born after the Thales Group bought the participation of Alcatel in the two joint-ventures between Alcatel and Finmeccanica, Alcatel Alenia Space and Telespazio.-History:...

 and EADS Astrium Satellites.
  • Structure is based on a central tube (the vertebral column of the satellite), like the Spacebus design, with additional carbon and aluminium panels (Section 2800 mm x 2490 mm, Launcher Interface: 1666 mm)
  • Chemical propulsion
    Spacecraft propulsion
    Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...

     with a 500 N Apogee Engine and 16 x 10 N thrusters
    Rocket engine
    A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...

    ; Propellant tanks (Max 4200 kg of bipropellant) and Helium tanks (2x150 litres)
  • Electrical propulsion
    Ion thruster
    An ion thruster is a form of electric propulsion used for spacecraft propulsion that creates thrust by accelerating ions. Ion thrusters are categorized by how they accelerate the ions, using either electrostatic or electromagnetic force. Electrostatic ion thrusters use the Coulomb force and...

     with Xenon
    Xenon
    Xenon is a chemical element with the symbol Xe and atomic number 54. The element name is pronounced or . A colorless, heavy, odorless noble gas, xenon occurs in the Earth's atmosphere in trace amounts...

     tanks (Max 350 kg) ; PPS 1350 thrusters Thruster Orientation Mechanisms
  • Power generation and distribution offering both 100V and 50V regulated buses, accomoding two GaAs
    Gaas
    Gaas is a commune in the Landes department in Aquitaine in south-western France....

     solar array wings with 4 to 6 panels ; modular Lithium-ion battery
  • Attitude and Orbit Control
    Attitude dynamics and control
    Spacecraft flight dynamics is the science of space vehicle performance, stability, and control. It requires analysis of the six degrees of freedom of the vehicle's flight, which are similar to those of aircraft: translation in three dimensional axes; and its orientation about the vehicle's center...

     (ADCS) with Gyros, Star and Sun Sensors, Reaction Wheels
  • Data Handling accommodating a 1553-bus for payload
  • Payload allowing for a modular-concept-based setup, comprising an antenna module for easier antenna accommodation and efficient assembly and testing.

Alphasat I-XL

Inmarsat
Inmarsat
Inmarsat plc is a British satellite telecommunications company, offering global, mobile services. It provides telephony and data services to users worldwide, via portable or mobile terminals which communicate to ground stations through eleven geostationary telecommunications satellites...

 awarded a contract to EADS Astrium Satellites for a first use of such a platform. The satellite is named Alphasat I-XL, and will augment Inmarsat's Broadband Global Area Network (BGAN) service. The satellite will support a new generation of mobile technologies and enable communications across Europe, Asia, Africa and the Middle East is set to launch in 2012.

First journey for Alphabus

The first service module of the new Alphabus completed its first journey at the end of January 2010 – from Cannes
Cannes
Cannes is one of the best-known cities of the French Riviera, a busy tourist destination and host of the annual Cannes Film Festival. It is a Commune of France in the Alpes-Maritimes department....

 to Toulouse
Toulouse
Toulouse is a city in the Haute-Garonne department in southwestern FranceIt lies on the banks of the River Garonne, 590 km away from Paris and half-way between the Atlantic Ocean and the Mediterranean Sea...

, in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

. The three-day trip used an exceptional convoy made up of a 20 m-long lorry carrying the satellite container, several escort cars and a police escort to close off streets and redirect traffic as they passed through urban areas.

External links

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