TRAJECTORY ANALYSIS OF MAGNETO-PLASMA SAIL COMPARING WITH OTHER LOW THRUST PROPULTION SYSTEMS

摘要

Trajectory design using low thrust propulsion system has to take into account of thrust direction angle, thrust magnitude, and thrust/power ratio as constraints. For example, the thrust direction angle of Magneto-Plasma Sail (MPS) is restricted to near the opposite direction of the Sun, while that of Ion Engine System (IES) is basically free if power and thermal conditions permit. The thrust to power ratio of MPS and IES are assumed 100-250mN/kW and 20-30mN/kW, respectively. This paper analyzes the characteristics of trajectories of low thrust propulsion systems in order to compare MPS with other low thrust propulsion systems. Low thrust propulsion mission performance is represented by three parameters; initial thrust/spacecraft mass ratio (acceleration), thrust angle and specific impulse, Isp. It is assumed that electrical power provided to the propulsion system is inversely proportional to the square of heliocentric distance, the thrust angle from transversal direction ranges from 0 to 360 deg. and the spacecraft mass decreases as the fuel is expended. The possible application of MPS to outer and inner solar system missions is finally discussed.