Gear-Part-Flying Mechanism for planetary exploration spacecraft landing

For planetary exploration, spacecrafts need to land softly. Conventional methods in previous missions have problems such as high rebound, impossibility of reuse, increase of the equipped mass, and expensive cost. To solve these problems, the author proposes a novel landing mechanism called Gear-Part-Flying Mechanism (GPFM). The main components of GPFM are the body, the head, and the gear. Here, the body corresponds to a spacecraft. GPFM realizes soft landing by converting the body's mechanical energy to the mechanical energy of the head and gear. The energy conversion is obtained effectively by the separation of the body and the head at the optimal timing. In comparison with the previous landing methods, the advantages of GPFM are as follows: (i) GPFM is reusable. (ii) GPFM is effective to suppress the body's rebound. (iii) GPFM is effective for both weight and cost saving of landing mechanisms. In this paper, the soft landing performance of GPFM is discussed. First of all, for simulation analysis, the model of GPFM is obtained assuming that it is a single-axis falling-type problem. The values of parameters are determined based on the 1/6 G similarity rule. This paper evaluates the robustness of GPFM against the variations of some parameters such as the ground stiffness, the body mass, the equipped mass, and the separation delay. For evaluation, this paper focuses on the maximum rebound height of the body. Simulation results reveal that GPFM has well robustness against the uncertainties of the ground stiffness, the body mass, and the equipped mass. However, the delay of separation causes a significant degradation of its performance.