Analytical estimation of probabilities of impact on Mars and Earth-Moon system for planetary protection assessment of Hayabusa2 extended mission

Abstract

This paper reports the results of the estimation of the probabilities of impact on Mars, Earth, and the Moon for the asteroid probe Hayabusa2 in its extended mission. The probabilities of impact were estimated using an analytical method instead of a computationally expensive Monte Carlo simulation. The results show that the probability of impacting Mars is $5.45\times {10}^{-7}$, which is sufficiently small to meet the planetary protection requirements of the Committee on Space Research. The probabilities of impacting Earth and the Moon are also estimated as $0.0116$ and $1.62\times {10}^{-9}$, respectively, which are found to be sufficiently small.