Drilling Results in Ice‐Bound Simulated Lunar Regolith

Reaching the cold traps at the lunar poles and directly sensing the subsurface regolith is a primary goal of lunar exploration, especially as a means of prospecting for future In Situ Resource Utilization (ISRU) efforts. The Construction and Resource Utilization Explorer project (CRUX) addressed technology development associated with a modular, drilling‐based payload to achieve this goal. As part of the development of a lunar drill capable of reaching a depth of two meters, a preliminary drilling study was performed using custom designed drill bits and augers in simulated ice‐bound lunar regolith. Lunar regolith is known to be very abrasive, but the mechanical properties and “drillability” of the purported ice‐bound material in the lunar cold traps is unknown. Preliminary drilling experiments were performed in the frozen samples, to determine the effectiveness of the drilling hardware and to point the way towards optimized drilling strategies. Additionally, a preliminary experiment was performed to demonstrate the utility of converting drilling energy per volume (Specific Energy) to the Unconfmed Compressive Strength (UCS) of the simulated frozen regolith. The results showed that the drilling hardware was capable of penetrating into the samples and that this was most effectively done at slow rotational speeds (< 60 RPM) and with a low axial force (weight‐on‐bit). The results also indicate that the specific energy of drilling is correlated to the UCS of the material tested.