SkyBridge LEO satellites: optimized for broadband communications in the 21st century

Presents an overview of the SkyBridge system design and provides technical details about the SkyBridge satellite design. The specificity of the SkyBridge broadband satellite system is presented first. The use of a non-geostationary (LEO, low Earth orbit) satellite constellation, associated with the Ku-band for both the user and feeder communication links are primary discriminators. They allow the use of a wide frequency bandwidth, in excess of 1 GHz. Other system features include fixed 700 km diameter service areas, and the use of neither on-board processing, nor inter-satellite links. These features shape the design of the satellite. The satellite communications payload is made of 18 Ku-band transparent (bent-pipe) transponders arranged on the Earth panel. The steerable antennas implement electronic beam shaping, to optimize performance within coverage and minimize interference outside. Interference control allows for the protection of the geostationary services and the maximization of the frequency re-use possibilities and thus system capacity. The satellite bus is designed to maximize the number of satellites accommodated under the launchers shroud. The shape of the satellite, the use of efficient propulsion and electric system features allow to pack 4 satellites in conventional launchers and 8 to 10 in new generation big launchers, thus minimizing the cost of putting the satellite constellation into orbit