Abstract <p>The paper considers the problem of stabilizing a spacecraft with a three-axis magnetic attitude control system in the vicinity of an unstable gravitational equilibrium position. A special reference motion is constructed using the particle swarm optimization method. This motion should provide a minimum projection of the control torque onto the geomagnetic induction vector. In addition, control gains are sought using the particle swarm optimization method to ensure asymptotic stability of the obtained motion. However, the problem of loss of stability arises in the presence of disturbances not taken into account at the stage of constructing the reference motion. The paper proposes a method for selecting control gains that allows maintaining asymptotic stability in a disturbed case.</p>