Deep drilling on Mars: pneumatic chip clearing model for the RedWater mining system

Mining water ice on Mars is a vital, near-term step to enable in-situ resource utilization (ISRU) and sustainable human exploration. Large quantities of water are required for propellant production and life support systems. Recent analysis of orbital data points to vast buried ice deposits in the Martian mid-latitudes. The RedWater system is a deep drilling and water-well system engineered to access and extract water from these ice deposits. RedWater accesses the buried ice by drilling through the overburden and using compressed gas to pneumatically clear the drill cuttings, or chips, out of the resulting borehole. Unlike terrestrial drilling, where heavy water-based slurries remove cuttings, Martian operations demand low-mass, gas-driven solutions robust to the planet's low temperatures and atmospheric pressures. This paper presents a pneumatic chip clearing model for deep drilling operations on Mars, quantifying the minimum gas mass flow rates necessary to efficiently transport drill cuttings. The model applies terrestrial, pneumatic vertical conveying correlations and tests them against a range of Mars-relevant conditions. Experimental validation includes a dedicated test setup in vacuum, and two tests with the end-to-end RedWater system. The model shows reasonable agreement with experimental results in predicting gas flow requirements, providing useful guidance for mission architectures utilizing pneumatic drilling and mining on Mars.