We develop a new model of attitude motion of spacecraft «Foton». The model is based on Euler's dynamic equations of a rotational motion of a rigid body. It takes into account four external mechanical torques acting upon the spacecraft: a gravitational torque, an aerodynamic torque, a torque which has constant components in a spacecraft body fixed coordinate system, and a torque from the Earth magnetic field. We use the special geometric model of the spacecraft outer shell. The detailed form of the expressions that define the torques above is adjusted with the spacecraft motion concerned. The model was tested in the problem of reconstruction of the «Foton M-2» attitude motion by processing onboard measurements of the Earth magnetic field strength. This spacecraft was in orbit in the period 31.05 - 16.06.2005. The use of the new model resulted in some increase of the reconstruction accuracy.

Theoretical and applied problems of mechanics