Phobos and Deimos, the two small and enigmatic moons of Mars, represent crucial targets for advancing our understanding of planetary system formation and evolution. Despite decades of study, their origin remains one of the most debated open questions in planetary science, with hypotheses ranging from their capture as primitive asteroids to their formation through a giant impact involving Mars. These competing scenarios carry profound implications for our knowledge of both Martian history and the processes that shaped the early Solar System. From an observational perspective, Phobos and Deimos stand out as some of the darkest and most spectrally red objects known, yet no analog materials identified on Earth or elsewhere have been able to reproduce their unique spectrophotometric properties. This raises fundamental questions about their composition, surface alteration processes, and potential connections to other classes of small bodies.
This session aims to bring together contributions from diverse disciplines—remote sensing, laboratory experiments, numerical modeling, and mission science—with the common goal of investigating the physical and compositional properties of the Martian moons. Topics of interest include, but are not limited to, visible and infrared observation, surface morphology, regolith properties, thermal behavior, and space weathering processes. Special attention will also be given to recent and upcoming datasets from spacecraft observations, as well as to new mission concepts and instrument developments designed to explore these enigmatic satellites. By fostering interdisciplinary dialogue, the session seeks to advance our understanding of Phobos and Deimos and to place them in the broader context of planetary formation and evolution across the Solar System.
Jacob Kegerreis