地球接近小惑星軌道変更ミッションにおける速度増分の変動を考慮した軌道設計

抄録

This paper discusses the conceptual trajectory design associated with the impulsive deflection of a potentially hazardous asteroid (PHA) with considering uncertainty of velocity increment that spacecraft gives to the PHA at the time of collision. The effect of the uncertainty is evaluated as the worst value of the closest approach distance between the PHA and the Earth by modeling the uncertainty as a convex model, where the uncertainties of magnitude and the direction of the velocity increments are independently varied. It is shown that the worst value is determined uniquely without searching in the convex hull. Then, the most efficient spacecraft trajectory is evaluated by maximizing the worst approach distance in terms of the Earth departure date and the asteroid arrival date of the spacecraft under C₃ constraint that considers the mission feasibility. The importance of considering the uncertainty is demonstrated by comparing the optimum trajectories with and without the uncertainty. Additionally, it is shown that the uncertainty of the velocity increment direction has the significant effect on the deflection of the PHA.