Une configuration de satellite de telecommunication geostationnaire avec plate-forme de service pointee sur le soleil “moyen”

This study was carried out at CNES within the framework of the STAR project. The configuration described in this paper deviates from present-day configurations of three-axis stabilized geostationary communications satellites by the fact that almost all service instruments are installed together on one part of the vehicle, the service module, which, while in station, remains pointed relative to the “mean” sun direction and the north star. The telecommunication payload is then placed on a counter-rotating part relative to the service module so as to remain pointed towards the earth centre; a sun-blind attached to the module protects the payload against sun radiation. The advantages and drawbacks pertaining to this configuration are brought to light by dimensioning studies: important solar disturbing torques and difficulties in antenna positioning, but on the other hand important capacities of heat rejection for the pay-load and the module, improvement of the vehicle pointing precision and greater efficiency in the propulsion system.