Subsurface investigation of planets, moons and other Solar System objects either by radar or by other techniques can provide important insights into their composition, structure and evolution; the potential existence of habitable environments; and the availability of critical in situ resources for supporting future human exploration. Abstracts addressing results from current missions, Earth-based observations, theoretical and laboratory analyses relevant to the interpretation of radar data, field investigations of analogue environments, and potential future investigations, are specifically encouraged.