Design of control laws for trajectory correction maneuver on interplanetary mission

Abstract

Design of the Trajectory Correction Maneuver(TCM) is needed for success of interplanetary missions. There are unexpected trajectory errors(many perturbations, initial launch vehicle error, and so on), the spacecraft can’t reach a designed aim point without correction maneuver. Trajectory is occasionally corrected by low thrust inputs. To provide robustness for variety of spacecraft maneuvers, we study about Formation Flying(FF). The principle of the trajectory correction maneuver is based upon a classical element feedback control using fixed low thrust for spacecraft orbital maneuvers. Then, we apply to TCM with consideration of time. Because formation flying is unable to make spacecraft reach up to an aimed point in the desired time. Flight time is very important factor for interplanetary missions. For calculation of perturbations and other forces, Gauss’s Variational Equations(GVEs) has been used. The stability of the system is proven with Lyapunov approach. Orbital elements are coupled each other so there are significant difficulty in selection of the control gains. In this research, we proposed an approach to select reasonable gains by trial and error. In this thesis, we can obtain sets of control gain which guarantees stability of the system by element feedback control. We apply to nominal trajectory(Earth to Mars transfer orbit) and the spacecraft reaches an aimed point on time, orbit elements converge to desired values.