the Mother of all Satellites

Britain is developing one whopper of a telecom satellite
Weighing it at six metric tons, the Alphasat I-XL will be one of the largest commercial satellites in existence upon its completion. The satellite, sponsored by London based industrialist Inmarsat, will provide high-speed internet service in Europe, Asia, and the Middle East.Inmarsat maintains a high-speed global broadband network, called BGan. BGan is made up of already large I-4 satellites, but it is falling behind broadband demands and needed an even bigger satellite partner to anchor the network. That’s where the I-XL comes roaring into the picture. It will support over five times the capability of its predecessors. The satellite will allow business people to get half-megabit internet connections on land and sea, anywhere in the world, no matter how remote. It is attracting significant support from journalists, disaster relief workers, the maritime industry, and the petroleum industry. The system uses laptop size terminals to catch the signal.EADS Astrium has been tasked with providing the brains for this brawny satellite. The firm is enthused about the new business venture with Inmarsat. They feel their signal processing and central processing capabilities will give the satellite an unbeatable edge."This satellite will access additional spectrum and it will be able to supply approximately five times the communications capacity of a single Inmarsat 4 satellite. With advances we've made, we've been able to pack an awful lot more electronics within the existing volume. It is a technology step forward in terms of the brains of the satellite which is built in the UK," said Dave Robson from EADS Astrium, the firm designing the satellite's signal processing.Astrium will also be manufacturing the spacecraft chassis and is partnering with Thales Alenia Space for this part of the work.The European Space Agency (ESA) and France's space agency, CENS, are collaborating on the project to provide a sufficient platform to support the satellite's needs. The new platform is dubbed “Alphabus” and is designed to help Europe stay competitive in the commercial satellite market. Inmarsat will be its first commercial customer. The Alphabus platform can support satellites of up to eight tons and 18 kW of payload power. It also is looking to implement ion thrusters in the future to provide a more efficient boost for large satellites in order to help them stay in orbit.The I-XL features a beefy 12m aperture antenna reflector. Its mission length is 15 years, and it will require a hearty 12 kW of power during this time. The I-XL will likely have to launch on an Ariane 5 rocket, Europe's premier launch vehicle. A launch target of 2013 has been set.