Geometry and Structural Stability of Lunar Lava Tubes

摘要

Establishment of extraterrestrial habitats on other planets is of interest to research and industry. Underground habitats, given that they are not exposed to extreme hazards such as radiation, meteorite impacts, and temperature fluctuations, can potentially serve as secure shelters for future human exploration. Images and measurements from SELENE and LRO support the presence of natural openings on the Moon. Data from GRAIL also investigated the possibility of the existence of large empty tunnels (1-2 km wide) in the lunar lava flows. Those tunnels could have been created when a crust formed on top of the lava flows. Using the characteristics and the morphology of the lava flows, an analytical solution has been developed to estimate the size of the lunar lava tubes. Also, a series of numerical simulations has been conducted to investigate the stability of the lava tubes for different sizes and material properties. The numerical solutions provide a more refined approach than previous attempts at investigating the stability of the lunar lava tubes. The results show that stability is influenced by the roof thickness and rock properties, particularly the tensile strength of the solid lava. Both analytical and numerical simulations show that the existence and stability of lunar lava tubes with widths of 1 km or more is possible, which agrees with the GRAIL observations. Also, the study shows that the tensile strength of the rock mass is a crucial parameter for stability assessment. For any particular width and height of the lava tubes, lower tensile strengths of the rock necessitate larger roof thicknesses for the lava tubes to remain stable.