Measurement of Small Cohesion of JSC-1A Lunar Simulant

Because of the difficulty of applying low, effective confining pressure in a triaxial test, the reported small cohesion of JSC-1A lunar simulant from past research is neither accurate nor reliable. To develop an effective way to measure the cohesion parameter, a new method was adopted and demonstrated. As the value of the critical height of a vertical cut is proportional to the cohesion of a soil, the cohesion of JSC-1A simulant was obtained through simple calculations based on the critical height measured. Footprint demonstrations were also used to illustrate the existence of cohesion in JSC-1A simulant, in a comparison with the photograph of footprints of astronauts on the Moon. A group of critical height tests was conducted to obtain the cohesion of lunar simulant JSC-1A for a range of densities from 1.61 to 1.96 g/cm3. It was found that the cohesion of JSC-1A simulant varies in the range from 0.0 to 1.1 kPa, in an approximately linear relationship with the soil density.