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A 3D thermal model that includes a discrete subsurface exponential density profile, surface shadowing and scattering effects has been developed to simulate surface and subsurface temperatures across the Moon. Comparisons of the modelled surface temperatures with the Lunar Reconnaissance Orbiter’s Diviner Lunar Radiometer Experiment (“Diviner”) measured temperatures show significant improvements in model accuracy from the inclusion of shadowing and scattering effects, with model errors reduced from ~10 K to ~2 K for mid-latitude craters. The 3D thermal model is used to investigate ice stability at potential landing sites near the lunar south pole, studied for Roscosmos’ ‘Luna Resource’ (Luna 27) lander mission on which the ESA PROSPECT payload is planned to fly. Water ice is assumed to be stable for long periods of time (>1 Gyr) if temperatures remain below 112 K over diurnal and seasonal cycles. Simulations suggest ice can be stable at the surface in regions near to potential landing sites in permanently shaded regions and can be stable below the surface in partly shaded regions such as pole-facing slopes. The simulated minimum constant subsurface temperature (where the seasonal temperature cycle is attenuated) typically occurs at a depth of ~50 cm and therefore the minimum depth where ice can be stable is A 3D thermal model that includes a discrete subsurface exponential density profile, surface shadowing and scattering effects has been developed to simulate surface and subsurface temperatures across the Moon. Comparisons of the modelled surface temperatures with the Lunar Reconnaissance Orbiter’s Diviner Lunar Radiometer Experiment (“Diviner”) measured temperatures show significant improvements in model accuracy from the inclusion of shadowing and scattering effects, with model errors reduced from ~10 K to ~2 K for mid-latitude craters. The 3D thermal model is used to investigate ice stability at potential landing sites near the lunar south pole, studied for Roscosmos’ ‘Luna Resource’ (Luna 27) lander mission on which the ESA PROSPECT payload is planned to fly. Water ice is assumed to be stable for long periods of time (>1 Gyr) if temperatures remain below 112 K over diurnal and seasonal cycles. Simulations suggest ice can be stable at the surface in regions near to potential landing sites in permanently shaded regions and can be stable below the surface in partly shaded regions such as pole-facing slopes. The simulated minimum constant subsurface temperature (where the seasonal temperature cycle is attenuated) typically occurs at a depth of ~50 cm and therefore the minimum depth where ice can be stable is 0

The propagation of extremely low frequency (ELF) electromagnetic waves in the Earth's ionospheric cavity and the associated resonance phenomena have been extensively studied, in relation with lightning activity. We perform a similar investigation for Titan, the largest moon of Saturn. There are important differences between Earth and Titan, as far as the cavity geometry, the atmospheric electron density profile, and the surface conductivity are concerned. We present an improved 3D finite element model that provides an estimate of the lowest eigenfrequencies, associated quality factors (Q-factors), and ELF electric field spectra. The data collected by the electric antenna of the Permittivity, Waves, and Altimetry (PWA) instrument reveals the existence of a narrow-band signal at about 36 Hz during the entire descent of Huygens upon Titan. We assess the significance of these measurements against the model predictions, with due consideration to the experimental uncertainties.