A new method to determine the grain size of planetary regolith

TL;DR

This paper introduces a remote sensing method to determine planetary regolith grain size using thermal inertia measurements, revealing size-dependent regolith characteristics across small and large celestial bodies.

Contribution

A novel method leveraging thermal inertia to estimate regolith grain size on planetary surfaces, aiding future exploration missions.

Findings

Small bodies have coarse regolith (mm to cm)

Large bodies have fine regolith (10-100 micrometers)

Method improves understanding of surface properties

Abstract

Airless planetary bodies are covered by a dusty layer called regolith. The grain size of the regolith determines the temperature and the mechanical strength of the surface layers. Thus, knowledge of the grain size of planetary regolith helps to prepare future landing and/or sample-return missions. In this work, we present a method to determine the grain size of planetary regolith by using remote measurements of the thermal inertia. We found that small bodies in the Solar System (diameter less than ~100 km) are covered by relatively coarse regolith grains with typical particle sizes in the millimeter to centimeter regime, whereas large objects possess very fine regolith with grain sizes between 10 and 100 micrometer.