Pulsed plasma ice drilling for Mars' polar layered deposits

Hot-tip melt-probes for accessing Mars' polar layered deposits (PLD) are highly inefficient due to heat conductive losses. A pulsed plasma ice drilling method is utilized to explore the possibility of cracking ice to reduce the heat loss since cracked or granular ice has a lower thermal conductivity. Plasma discharges with different pulse energy under atmospheric pressure with two electrodes embedded on a clear ice plate demonstrates the area-of-influence based on the cracked area. A transient needle probe is employed to quantify the change in thermal conductivity of granular ice created by pulsed plasma. This is compared to various granular ice size distributions separated by a sieve shaker to explore the relationship between the ice granular size and the thermal conductivity of powdered ice, which will then determine the pulsed plasma discharge targeted cracking parameters, such as number of discharges, energy per pulse, input power, etc. Different arrays consisting of spark gaps in parallel and series are tested both in air and in ice for potential hybrid conceptual design. The incorporation of hot-tip probes with this pulsed plasma method will improve the rate of penetration inside ice deposits during interplanetary missions with limited solar power access.