A Fractionated Radar Sounder Concept for Subsurface Exploration of Saturn’s Icy Moon Enceladus

Abstract:
Low-frequency radar sounders offer unique measurement capabilities for exploring the subsurface of planetary bodies. However, these instruments face limitations due to the near-omnidirectional characteristic of dipole antennas commonly used at lower frequencies. This characteristic results in the collection of clutter from off-nadir angles, potentially masking the signals of interest coming from subsurface layers in the nadir direction, thus complicating the interpretation of subsurface data. To address these limitations, we are investigating the feasibility and potential of a fractionated HF-band radar sounder satellite constellation for a mission scenario to Saturn’s icy moon Enceladus, as part of an ESA study. The specific configuration of satellites, operating in formation, can enable the synthesis of a large antenna array, offering the following potential benefits: i) effective suppression of off-nadir clutter using beamforming approaches, ii) increased sensitivity, and iii) flexibility for implementing advanced imaging modes.