|Manufacturer||Thales Alenia Space|
EADS Astrium Satellites
|Country of origin||Europe|
|Applications||Communications satellite bus|
|Launch mass||6,550 kilograms (14,440 lb)|
|Power||up to 22 kW|
|Design life||15 years|
|Maiden launch||Inmarsat-4A F4|
25 July 2013
Alphabus is a family of heavy geostationary communications satellites developed by a joint venture between Thales Alenia Space and EADS Astrium Satellites in France, with support of the Centre national d'études spatiales (CNES), the French space agency and the European Space Agency (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 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).
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 and Eurostar families, respectively from Thales Alenia Space and EADS Astrium Satellites.
Inmarsat awarded a contract to EADS Astrium Satellites for a first use of such a platform. The satellite is named Alphasat (Inmarsat 4A F4), and will augment Inmarsat's Broadband Global Area Network (BGAN) service supporting a new generation of mobile technologies and enable communications across Europe, Asia, Africa and the Middle East. Alphasat was partially funded by ESA and UK Regional Development Agencies.
As well as its primary objective of providing in orbit validation of the Alphabus platform, Alphasat also carries four technology demonstration payloads (TDPs):
The first service module of the new Alphabus completed its first journey at the end of January 2010 – from Cannes to Toulouse, in 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.
Alphasat (Inmarsat 4A F4) was launched on 25 July 2013 from French Guiana by early August it had reached a holding position in geostationary orbit and had successfully deployed its solar arrays and 11-metre L-band AstroMesh reflector.