Two-Dimensional Experimental Investigation of Base-Extension Separation Mechanism with Telescopic Gear

Abstract

Spacecraft landing missions require a soft landing mechanism to prevent a large shock load and tipping over when landing on various types of terrain. The authors previously invented a novel landing mechanism called a telescopic-gear base-extension separation mechanism that operates by means of energy transfer and an adjustable structure. This mechanism passively adjusts the shape of the landing gear according to the landing terrain and transfers the energy of the lander to a spring as potential energy. The outstanding performance of this landing mechanism was demonstrated analytically in a previous study. However, its feasibility was not confirmed, and an effective parameter design method for various shapes of terrains was not presented. Therefore, in this study, two-dimensional experimental investigations are conducted using a small-scale prototype to assess the feasibility of the landing mechanism for several types of terrain. An effective parameter design approach based on a mathematical model derived from the experimental results is presented in this paper. To improve the robustness of the landing mechanism, the lengths of the telescopic gears should be as large as possible, and the spring stiffness should be tuned within a certain range. For sloped ground in particular, the width of the lander is an additional important design parameter; a smaller width is preferable in theory. A robustness study and several important notes on the practical design aspects of the landing mechanism are summarized in this paper.