Alphabus

Alphabus is a European satellite bus company Astrium and Thales Alenia Space ( dec TAS), which was newly developed with the help of space agencies ESA and CNES to even heavier and more powerful geostationary communications satellites than using the existing satellite buses Euro Star 3000 Astrium and Spacebus 4000 TAS allow.

Construction

Alphabus is modular and consists of a service module, a payload module and an attached antenna support. The structure of the service module mainly composed of a tube in which the two tanks MMH and MON 3 are installed. The tanks are very lightweight and are made of titanium, which is wrapped with carbon fiber for stabilization. Each of the two tank holds 1925 liters of fuel. The total fuel weight is 3500-4200 kg plus three tanks coming from each 90 l for the helium used as the pressurizing gas. These provide an EAM apogee engine with 500 N thrust. The engine has a combustion chamber and exhaust nozzle ceramic. Alternatively, an S400 - apogee be installed with 400 N thrust. Furthermore, there are 16 control engines. The system for the four ion engines has tanks for 350 kg of xenon. The auxiliary equipment required for this are in sandwich panels made ​​of carbon and aluminum, which are attached to the central tube, spread.

The payload module has three levels to accommodate the communication electronics, and the antenna module is mounted on the payload module and at its sides. There are a maximum of 12 possible parabolic mirror, two of which may be greater than 3.5 m in diameter with the rest of the diameter of 2 m. However, he can carry a deployable antenna with 10 m diameter for mobile communications. Before this, however, can be aligned to the Earth, the satellite has its orientation in geostationary orbit at 90 ° compared to the normal orientation change .. The two facing north and south solar panels each consisting of four to six elements. The elements five and six fold laterally from element three. The elements of the solar panel using GaAs triple-junction solar cells. For the time in which no power is available from the solar cells, a lithium ion secondary battery modular exists.

Alphabus is energy consumption, a takeoff weight of up to a maximum of 22 kW. 8.8 t and designed 230 transponders payload.

The first satellite based on this bus is Alphasat I- XL, which was launched by an Ariane 5 ECA on 25 July 2013.