Sediment Sequestration for Hot Water Drilling Cryobots

This proposal responds to Focus Area 4: Robotic Systems for Space Exploration; subtopic S13.01: Robotic Mobility, Manipulation, and Sampling describes a need for technologies that provide improved robotic mobility for ocean world deep drilling and water access. This proposal addresses this need with a solution for sediment buildup in the melt stream of ocean world ice penetrating robots (cryobots) that descend via hot water drilling. Ocean worlds remain of critical interest for astrobiology but cryobots require deep drilling to reach areas of interest on Europa or the poles of Mars. Previously built and tested prototype cryobots such as Stone Aerospacersquo;s THOR system demonstrate high efficiency using downward-pointing closed cycle hot water drill (CCHWD) jets on the nose cone of the vehicle, however debris released from the ice could potentially obstruct a cryobot and it will accumulate as refreezing ice behind the cryobot excludes salt and sediment. Our proposed solution mitigates silt, solids, and salt accumulation using HWD jets in new ways. It uses the two-pronged approach of A) control of meltwater circulation, speed, and flow using jet orientation or mechanical rotation plus B) obliquely-oriented HWD jets to create Sequestration Side-Pockets (SSPs) in the surrounding ice. This system is part of an extended plan for using CCHWD jets to manage sediment for cryobots called MJOLNIR (Managing Jets of Liquid for Nullifying Ice Refuse). Control of vectored HWD jets equipped for selectable spray and variable pressure will hollow out SPPs on the side-periphery of the nose cone of a cryobot. These SSPs will accept and accumulate brine and sediment. Controlling jet pressure, angle, spray, and orientation gives precise control of meltwater circulation and speed for sediment transport and deposition. This allows sediment to settle out when appropriate, by centrifugally driving it into pre-cut pockets of still water.