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