The feature of raising the “Express-AMU3” and “Express-AMU7” satellites into geostationary orbit

At present, in order to increase the launch mass, raising satellites into geostationary orbit by their own propulsion subsystem is widely used. Oly the JSC “Academician M. F. Reshetnev “Information Satellite Systems” applied such a scheme for several satellites of their own design - "Express-AM5", "Express-AM6", "Express-80" and "Express-103". Along with this, some diversity of approaches to the implementa-tion of this operation can be noted. In particular, the orbit raising of the above satellites was carried out using the onboard propulsion subsystem based on SPT-100 plasma thrusters. The operation was carried out by one or two thrusters. The use of two thrusters of the "Express-80" and"Express-103" satellites was due to the desire to keep within a reasonable amount of no more than six months with a significant increase in the output mass. Nevertheless, the duration of the orbit raising of about 150 days, which took place dur-ing the raising of satellite data, is also excessively long. It is evidemnt that it can be reduced, other things being equal, only by increasing the available thrust of the thrusters. This can be achieved both by increas-ing the thrust of individual units, and by increasing the number of simultaneously used thrusters. Therefore, for the new Express-AMU3 and Express-AMU7 satellites (with dimensions similar to the Express-80 and Express-103 satellites), for which a paired launch was also assumed, both of these methods were used. For orbit raising, two SPT-100V thrusters and, additionally, an SPT-140D type thruster were used. The total thrust of a cluster of thrusters made it possible to count on a significant reduction in the duration of orbit raising in comparison with the Express-80 and Express-103 satellites. The SPT-140 thruster developed by JSC "Experimental Design Bureau FAKEL" was used in Russia for the first time. For its power supply, the CCS-140D control and conversion device was specially created at the JSC "Design Bureau Polyus". The use of a combination of three thrusters made it possible to significantly reduce the duration of the opera-tion of raising into geostationary orbit.