Indirect Optimization of Robust Orbit Transfer Considering Thruster Underperformance

In the life of a spacecraft the LEOP (Launch and Early Operational Phase) is one of the most critical, because the knowledge of the behavior of the S/C platform is still uncertain. This is, in particular, true for the propulsive maneuvers performed during the first phases of a mission, when the performance of the spacecraft and thrusters is still unknown. This chapter focuses on the determination of robust control laws to take into account dramatic thruster underperformance. The insertion of a spacecraft in a highly elliptic orbit with multiple apogee burns is considered as an example and the effect of non-nominal thrust in the first apogee maneuver is analyzed. An indirect optimization method is proposed in order to find a robust control law that guarantees “optimal” performance even in such an event.