Velocity pointing error reduction for symmetric spinning spacecraft via a two-burn scheme

Abstract

During axial thrusting of a symmetric spinning spacecraft, misalignment and center-of-mass offset can cause unwanted body-fixed torques. The two-burn scheme is applied to eliminate velocity pointing error. Solutions for angular velocity, Euler angle, and inertial velocity with nonzero initial conditions are derived in a new form for axisymmetric spacecraft with constant mass. Simulations show that the solutions closely match numerical simulations and the two-burn scheme decrease the velocity pointing error obviously. Based on the solutions, the effect of two-burn scheme is analyzed. The results show that the spacecraft will obtain the minimum velocity pointing error if the burn and coast times are controlled accurately. Also, the two-burn scheme allows for a lower spin rate and the spacecraft can be maneuvered at nonzero initial conditions compared with the continuous thrust scheme.