The Rock-Forming Minerals and Macroscale Mechanical Properties of Asteroid Rocks

Abstract

In the future, human activities in space, such as resource exploration and mining, definitely require the aid of geotechnical engineering. Rock samples obtained by sample-return missions via spacecraft and meteorites collected in the earth are usually rare, fragmented and arbitrarily shaped. These samples are difficult to be processed into coupon shapes required by traditionally macroscale rock mechanics testing methods (e.g., MTS tests). First, the performances of two effective medium methods and computational method of accurate grain-based modelling (AGBM) are compared with granitic samples, meanwhile the errors of these three methodologies are investigated. The AGBM is the most accurate, thus, it is extended to measure the mechanical properties of unconventional rock samples, Hammadah al Hamra 346 (HaH 346) asteroid meteorites. Second, the microstructure, mineral composition and mechanical properties of rock-forming minerals in HaH 346 meteorites are measured using microscale rock mechanics experiment (micro-RME); these properties are used to generate accurate grain-based models. Last, the macroscale Young’s modulus of HaH 346 meteorites is estimated using the AGBM. The present method is potentially beneficial for characterizing the unconventional rock samples during asteroid mining.

Keywords: extraterrestrial rock mechanics, asteroid mining, macroscale Young's modulus, microscale rock mechanics experiment (micro-RME), accurate grain-based modelling (AGBM)