Waste Heat-Based Thermal Corer for Lunar Ice Extraction

The water ice accumulated in the Permanently Shadow Regions (PSR) of the Moon is considered to be the most valuable resource on the moon since it can be processed to generate Oxygen for life-supporting and converted into LH2 and LO2 for satellite and spacecraft refueling. It has been demonstrated that water can be extracted from icy-soil through in-situ heating and then collected by re-freezing the sublimated vapor within a cold trap container. Under this research, a thermal management system (TMS) for Lunar Ice Miners was developed, which consists of a thermal corer that can strategically use the waste heat of on-board nuclear power sources for ice extraction, and a cold trap tank that can use the lunar cold environment as the heat sink for ice collection. In order to investigate heat exchange between the corer and icy-regolith during the thermal extraction process, a two-dimensional transient model was developed and built-in ANSYS FLUENT environment as user-defined functions (UDF). The UDF provides the user-defined material properties of the icy-regolith as a function of temperature and porosity, including specific heat, thermal conductivity, saturation pressure, and mass fraction of ice. The model was validated against experimental water extraction of Mars regolith and Lunar regolith. Both experiment and simulation demonstrated a complete sublimation of 10% wt of icy-soil within ~ 9 minutes, using a thermal corer with 6 inches in length, 0.6 inches in inside diameter, and wall temperature of 57 ?. On-going work focuses on optimizing the dimension of the full-scale corer, using the developed model, to achieve the targeted water collection of 2.78 kg/hr.