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Compression testing of rock in simulated lunar environment.
MISSING 1974; :1-21
Experiments were conducted by the Bureau of Mines on five types of simulated lunar rock (dacite, tholejitic basalt, vesicular basalt, pumice, and Duluth Gabbro) to study the effects of various simulated lunar environments on their strength and deformational properties. Specimens were tested in an ultrahigh vacuum (uhv) system at pressures ranging from atmospheric down to 10-11 torr and at temperatures of -130 deg, 20 deg, and 135 deg c. All tests were conducted with a servocontrolled testing machine. Rock specimens tested at 20 deg c in uhv exhibited significantly higher compressive strength and young's modulus than those tested at 20 deg c in atmospheric pressure. The magnitudes of increase are related to the porosities and permeabilities of the rock specimens; high porosity and permeability allow better outgassing and thus improve surface cleanliness in uhv. The compressive strength generally increases but young's modulus decreases as test environments change from 20 deg c in uhv to 135 deg c in uhv. No significant difference was observed in the physical properties measured at 20 deg c in uhv and - 130 deg c in uhv. Anisotropy in strength and young's modulus exist both in uhv and at atmospheric conditions with the same symmetry pattern. The orientations of the principal axes may, however, change from the atmospheric to uhv condition. The results indicate that rock fragmentation in lunar environment will require more energy than that at 20 deg c in atmospheric pressure. Work done under an agreement with the office of advanced research and technology, national aero
Mining; Rock mechanics; Atmospheric pressure
IH; Report of Investigations
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division