Pressure-Sinkage Testing of Lunar Regolith Simulants in Ambient Pressure and Vacuum

Pressure-Sinkage Testing of Lunar Regolith Simu-lants in Ambient and Vacuum Environments: Two lunar regolith simulants were selected for pressure sinkage testing : Lunar Highlands Simulant (LHS-1E) from the University of Central Florida Exolith Lab [7] and Black Point-1 (BP-1) [8] a basaltic mechanical lunar mare simulant, sourced as fines from a quarry at the Black Point lava flow near Flagstaff, Arizona. A Bevameter pressure-sinkage test rig was used that consisted of a frame made of aluminum modular extrusions that were bolted together, an electro-mechanical linear actuator with various sizes of square and rectangular plates mounted to it and a simulant test bin which was made out of 0.95 cm thick acrylic and is 40 cm tall with horizontal dimensions of 30.48 x 30.48 cm. The linear actuator was controlled by an Arduino microprocessor programmed in C+ language. The time, actuation distance and force measured with a sandwiched load cell were data logged for analysis.
The regolith simulant was tested at various bulk densities ranging from 1.42 grams/cm^3 to 1.86 grams/cm^3. The simulant was carefully prepared by sieving it into the test bin and then if compaction was required, a 1.91 cm thick plywood board cut to the size of the simulant bin wrapped in landscape fabric, with a 90 W vibration motor bolted to the board, was placed on top of the regolith simulant and vibrated. Recent work by others [9] has indicated substantial differences between ambient and vacuum properties and a high sensitivity to the bulk density. The results of these ambient and vacuum tests will be presented with a full analysis to follow in a journal publication.