Roving on ice: Field testing an Ice Screw End Effector and sample collection tool

Icy moons are tantalizing environments in which to search for life beyond Earth and understand the workings of the solar system. However, they pose new challenges for exploration. The low gravity, unknown terrain complexity, and desire to go below the surface (ideally to a water ocean) require new robotic mobility systems for viable roving. We present the iterative development of an Ice Screw End Effector (ISEE). Using an actuated alpinist ice screw, the tool can support a 250N load in glacial ice as the hand/foot of a climbing rover while simultaneously extracting 1.4cm diameter ice cores. These smaller, more manageable cores can replace monolithic ice cores for collection in inhospitable terrain where robotic access is required. The collection and analysis of ice cores can explain climate trends, show changes in pollution levels, document extremophile life, and reveal volcanic activity. A sequence of small cores could be collected from various stratigraphic layers by a climbing robot that can ascend sheer ice walls, descend crevasses, or maneuver across the ceilings of ice caves. This low-mass, spatially distributed ice collection strategy presents the opportunity for new paradigms in ice collection, such as 2D grid sampling from ice cliffs, horizontal collection of material along ice strata, and low-impact sampling in biologically sensitive areas. We present the motivation, electromechanical design, and testing results for the ISEE and discuss the findings of the recent deployment of the tool. The required weight on bit for various densities and temperatures of ice tested in the laboratory is presented and a force-control loop for modulating this value is demonstrated. A mechanism for sample transfer is described along with a simple sample caching architecture. Descriptions of the field sites and samples obtained is also included. We outline a path forward for future tool iteration and prospective robotic integration for the next series of deployments.