Study of Leg Arrangement for Stable Touchdown during Two-Step Landing for SLIM

Abstract

Smart Lander for Investigating Moon (SLIM) is a lunar lander that demonstrates pinpoint guidance to the target site. From mission requirements such as landing on rough terrain and slopes, SLIM adapt a landing method called the two-step landing. In this study, we explored landing leg arrangements suitable for the constraints from launch to touchdown in the SLIM mission and then realized stable touchdown on the lunar surface. For this challenge, simulation was constructed for the touchdown dynamics of SLIM, and Monte Carlo analysis was conducted to understand the tendencies. Moreover, the obtained leg arrangement was confirmed as making stable touchdown possible within the range guided by the guidance and navigation control system. In the process of these studies, we also revealed that it is possible to analyze touchdown dynamics efficiently by focusing and considering the critical results derived from a statistical analysis using the Monte Carlo method even in complex boundary conditions for the realistic spacecraft.