Development of hybrid landing gear for OMOTENASHI surface probe

This study presents technologies of the triple hybrid landing gear for the OMOTENASHI(Outstanding Moon exploration Technologies demonstrated by Nano Semi-Hard Impactor) spacecraft, which consists of an airbag, a crushable material as a shock absorber, and an impact resistance structure. The inflated airbag has capability to possibly mitigate impact acceleration at the instant of landing and submergence into regolith that covers a planetary surface. The crushable material with lattice structures, manufactured by a metal 3D printer, serves a dual purpose: it dissipates kinetic energy and controls the impact acceleration at landing by compressing itself within a designed deceleration distance. Further, in the impact resistance structure, the protective object is filled with resin and hollow glass beads, and the impact resistance is improved while the weight reduction is maintained. This paper provides the technical details such as the required specification, verification test results, and assembly result of the surface probe as the smallest lander of the OMOTENASHI spacecraft. • The triple hybrid landing gear appeared for the world’s smallest lunar lander. • Shock absorber, airbag, and shock-resistant structure were complementarily combined. • The shock absorber with excellent mounting capability was produced by a 3D printer. • The airbag shape was designed with the Terra-mechanics theory. • Development tests suitable for small landers were demonstrated.