Study of Plane Angular Motion of a CubeSat Nanosattellite Using Phase Portraits

This paper considers the plane motion relative to the center of mass of CubeSat nanosatellites under the action of aerodynamic and gravitational moments in low Earth orbits. The phase plane method is used for qualitative assessment of motion parameters. Conditions under which the type of phase portrait changes have been obtained. Analytical expressions have been found to determine the equilibrium positions of a nanosatellite relative to the center of mass in the orbital coordinate system with a displacement of the center of pressure relative to the center of mass along two coordinates. Two models of angular motion are compared: the original model, which takes into account the shape of the nanosatellite and its position relative to the oncoming flow, and a simplified one, in which the dependence of the aerodynamic moment on the angle of attack is approximated by a sinusoid.