Electromagnetic characterization of a crushed L-chondrite for subsurface radar investigations of solar system bodies

Radar sounders are becoming essential methods for the exploration of the Earth, Planets and the interior of small Solar System bodies. The performance of a radar is strongly related to the electromagnetic parameters of the materials composing the body surface and subsurface. Given the very limited access to planetary soil and rocks, meteorites represent important analogues of asteroids and Jovian icy moon crusts. Electromagnetic properties of meteorites are poorly known as they have seldom been investigated through extensive laboratory measurements as a function of frequency, temperature, and density. The present work builds upon a previous study on a solid chondrite sample, extending the measurements to the complex dielectric permittivity and magnetic permeability of a crushed L5 chondrite in the frequency range typical of the radars proposed for future space missions, such as AIDA, JUICE and EUROPA CLIPPER. The results show that for such dry granular materials the main parameter controlling the electromagnetic properties is the sample bulk density. Moreover, our results highlight the importance to account for magnetic properties in radar signal attenuation estimation for planetary exploration.