Granular Flow Characterization During Sampling Operation For Enceladus Surface Acquisition

A potential future mission landing on the surface of Saturn's moon Enceladus would represent a unique opportunity to probe the content of an extra-terrestrial ocean potentially hosting life beyond Earth. The content of the subsurface ocean is continuously ejected by plumes, and some of that material settles on the surface, as observed by the Cassini mission. The goal of a potential landing mission would be of collecting and analyzing samples from the upper 1 cm of the surface, made of most recently deposited material from plume fallback. However, the low surface gravity of Enceladus (1% of Earth's) represents a unique challenge for sample handling. This study focuses on the analysis of the novel Dual-Rasp sampling system enabling rapid sampling and collection of surface material into receptacles via momentum transfer. A numerical model based on the discrete element method (DEM) was developed to investigate the tool-soil interaction and the resulting granular material flow while performing surface sample acquisition. A systematic process for validating the DEM simulation model is presented, including an experimental test campaign expected to be conducted in a vacuum chamber in both lg and low-g environment.