Radar Attenuation for Subsurface Sounding on Enceladus: Effects of a Porous Ice Layer

The presence of a global ocean, the water-rock interface at the base of the ocean, and the inferred ocean composition derived from sampling the active plume at the south pole of Enceladus, make Saturn’s moon a promising location for habitable conditions in the Solar System. Due to its thin (<35 km) and cold ice shell, Enceladus is expected to exhibit favourable conditions for direct detection of the ice-ocean interface using low-frequency radar sounder instruments. Here we investigate the two-way radar attenuation in the Enceladus ice shell, focusing on the effect of a porous icy layer generated by Enceladus’ jet activity. Our results show that as little as 2% of the ice shell can be penetrated in regions covered by thick and strongly insulating porous layers. However, the high subsurface temperatures in these regions could promote the formation of brines at shallow depth that can be detected by future radar measurements.