Method for Calculating Thrust Vector Eccentricity Angle of Electric Thruster

Abstract

The installation of a propulsion device in space missions requires the thrust vector to be in line with the centroid of the satellite platform. If the installation is eccentric, interference torque occurs on the satellite body, which is not conducive for the attitude control of the whole satellite. In this paper, a method for calculating the thrust vector eccentricity angle by Gaussian surface fitting is proposed, which is suitable for a class of electric thrusters, for which the plume is conformed to point source distribution. For the cylindrical-shaped plume that cannot be regarded as a point source, a new weight function is proposed. A Hall thruster is considered an example to experimentally verify the method. Error analysis shows that the calculation accuracy in most of the cases is within 10%. To obtain the result of a small error, a preprocessing procedure is proposed before applying the method for optimization. Moreover, considering the contribution of the ion energy distributed along the angle, the calculation method is corrected and improved; and it is found that the thrust vector eccentricity angle of the Hall thruster is overestimated by about 20–30% when the angular distribution of the ion energy is not considered.