We estimate the sensitivity of a lander-based instrument for the passive radio detection of a subsurface ocean beneath the ice shell of Europa , expected to be between 3 km - 30 km thick , using Jupiter ’ s decametric radiation .
A passive technique was previously studied for an orbiter .
Using passive detection in a lander platform provides a point measurement with significant improvements due to largely reduced losses from surface roughness effects , longer integration times , and diminished dispersion due to ionospheric effects allowing operation at lower frequencies and a wider band .
A passive sounder on-board a lander provides a low resource instrument sensitive to subsurface ocean at Europa up to depths of 6.9 km for high loss ice ( 16 dB/km two-way attenuation rate ) and 69 km for pure ice ( 1.6 dB/km ) .