Evaluation of the potential for passive radio sounding of icy moons based on radar equation and ray tracing studies

Passive radar is an observational method that captures reflections of radio waves emitted by natural radio sources. In the RPWI (Radio and Plasma Wave Investigation) instrument that we will carry on JUICE (Jupiter Icy Moons Explorer), passive radar observations are planned to survey the surface and shallow subsurface of icy moons such as Ganymede. In addition, it is being considered for future missions to ice giant planets such as Uranus and Neptune, as well as lander missions to icy moons.
At present, to evaluate the feasibility of passive radar observations with JUICE/RPWI, we are estimating the intensity of Jupiter auroral radio waves reflected from moon surfaces from two perspectives: the radar equation and ray tracing.
Going forward, we aim to evaluate investigations of moons using Uranus/Neptune auroral radio waves, with the goal of paving the way for icy giant exploration for the first time since Voyager 2.
Written by KAWAKAMI Ayuto.