Ice Permafrost ‘‘Oases’’ Close to Martian Equator: Planet Neutron Mapping Based on Data of FREND Instrument Onboard TGO Orbiter of Russian-European ExoMars Mission

Abstract

We present the first results of Mars neutron sounding by FREND instrument onboard ESA’s Trace Gas Orbiter data analysis. Neutron flux mapping is performed with high spatial resolution, which allows to match epithermal neutron flux variation with relief’s geomorphological structures. Local regions with suppressed neutron flux indicate the presence of considerable amount of hydrogen atoms in the surface material, which is supposedly part of water molecules. Local regions in the equatorial latitudes of the planet with significant decrease of neutron flux are discovered, which points to large mass fraction of water ice in the soil material, ranging from tens to 100 $$\%$$ . Considering high water content, these regions are named ice permafrost ‘‘oases.’’ Estimates of ice mass fraction for 7 such regions are obtained based on neutron measurements analysis and end-to-end numerical modeling of the entire physical process of neutron sounding by FREND on Mars orbit. Possible reasons for formation of such ‘‘oases’’ and their significance for future Mars exploration are discussed.