The rock-forming minerals and macroscale mechanical properties of asteroid rocks

Abstract

In the future, human activities in space, such as asteroid mining, will require the aid of geotechnical engineering. Rock samples obtained by sample-return missions via spacecraft and meteorite collection are usually rare, fragmented and arbitrarily shaped. These samples are difficult to be processed into standard cylinders required by traditionally macroscale testing methods (e.g., MTS tests), leading to the application of microscale Rock Mechanics Experiments (micro-RME) to derive the macroscale Young's modulus of these samples. Firstly, the performances of three upscaling methods were compared in the context of granitic samples, including the Voigt-Reuss-Hill (V-RH) method, Mori-Tanaka (M-T) method and Accurate Grain-Based Model (AGBM). Additionally, the statistical errors of these three methodologies were quantified. Compared to V-R-H method and M-T method, the AGBM was found to be the most accurate. Secondly, the mechanical properties of rock-forming minerals and interphase in a Hammadah al Hamra 346 (HaH 346) asteroid meteorite were measured using micro-RME, which were used to generate AGBM. Lastly, the macroscale Young's modulus of the HaH 346 meteorite was estimated using AGBM based modeling. The present methodology is a potential candidate for investigating the mechanical property of unconventional rock samples during asteroid mining.