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Development, complex investigation, laboratory and flight testing of the magneto-gyroscopic ACS for the microsatellite
The key-problems of design, examination, laboratory' and flight testing of the attitude determination and control system (ADCS) dedicated for a microsatellite arc considered. The system consists of three pairs of the reaction wheels, three magnetorquers, set of Sun sensors, three-axis magnetometer and a control unit. ADCS, on one hand, is subjected to the high accuracy and reliability requirements, and, on the other hand, power consumption, total mass and volume limitations. It is meant for the LEO satellite with mass between 10 and 50 kg. The problems are solved within several steps, i.e. preliminary study of the satellite dynamics using asymptotical and numerical techniques, hardware and software design, testing of each actuator and sensor and the whole ACS on the test-bench dedicated specially for such a laboratory simulation. Finally flight testing has been carried out to validate ADCS functioning. In this paper both dynamics of the microsatellite with ADCS and mock-up of ADCS operation are studied. Reaction wheels control law parameters are chosen to provide the maximum degree of stability. The evolution of the reaction wheels angular momentum is also studied and the problem of the desaturation with use of the magnetorquers is solved. Attitude accuracy is estimated in terms of closed-form formulae. Some aspects of in-flight ADCS exploitation onboard the Russian microsatellite "Chibis-M" developed, designed and fabricated by the Institute of Space Research of RAS and orbited from SC "Progress" on 25th of January, 2012 are presented. Flight showed a good correspondence between analytical, numerical and laboratory' study with in-flight testing.