Keynote Speaker

Calin Tarau

Advanced Cooling Technologies, Lancaster, PA, USA


Tile: Autonomous Thermal Probe for Icy Planets Exploration

Abstract: NASA is interested in exploring the possibility of life in the ocean worlds of Europa, Ceres (Jupiter’s moons) and Enceladus (Saturn’s moon).  In each case, these ocean worlds are in fact thick layers of liquid water surrounded by ice crust. The shielding that the ice crust provides to these oceans against planetary radiation combined with the fact that, at the bottom, the liquid water is bounded by silica (on Europa), represent a favorable context for potential alien life existance. This kind of mission requires a reliable and autonomous ice penetration probe that can melt through the 30-50km of ice crust of these moons.  Advanced Cooling Technologies (ACT)’s Research & Development group have taken on this task, noting some particular points of concentration around challenges like surrounding temperature non-uniformity, possible obstacle encounter during melting and descent as well as temperature and pressure extremes experienced by the instrument. ACT has completed a feasibility study (Phase I NASA SBIR) working on an innovative melting probe design, and is currently developing a reduced scale electrically powered prototype (Phase II NASA SBIR). The final prototype/probe will have to be capable of melting the ice crust efficiently to save time, releasing itself from refreezing tail events, detecting and avoiding obstacles by changing the direction of motion or even melting and moving laterally to avoid large non-meltable areas, all of these autonomously. To enable these capabilities for the probe, the development focuses on a series of innovative features.  A first feature will be a pumped 2-phase loop that collects waste heat from the cold end of the thermos-electric convertors to focus it to the front of the probe. A second feature is a vapor chamber at the front that will collect the heat from the pumped 2-phase loop and focus the heat on the front/bottom for forward melting. A third and very important feature, consisting of variable conductance walls, will allow lateral melting only as needed to minimize the parasitic energy usage. This feature will passively release the probe when it gets stuck because of tail refreeze, will allow change of trajectory or even lateral motion to avoid wide obstacles.  A fourth feature will consist of water displacement nozzles that would allow steering of the probe during the ice melting. All these features will need to work together interacting with each other to increase probe’s reliability and avoid mission stoppers.  ACT’s team expects preliminary results from this Phase II development by September 2022 when some of these results will be presented at the “Dunarea de Jos” University of Galati.