The Science Case for Io Exploration

Abstract

Io is a priority destination for solar system exploration, as it is the best natural laboratory to study the intertwined processes of tidal heating, extreme volcanism, and atmospheremagnetosphere interactions. Io exploration is relevant to understanding terrestrial planets and moons (including the early Earth), ocean worlds, and exoplanets across the cosmos.1. Io is a priority destination for future exploration. Jupiter's innermost large moon, Io, is the most geologically active world in the solar system (Fig. 1). Io's surface is marked by hundreds of active volcanoes, erupting lava fountains, evolving sulfurous ices, enormous mountains, and deposits from towering volcanic plumes that pollute the Jovian system and feed its enormous magnetosphere. This unparalleled activity is powered by rampant tidal heating, where the gravitational interactions between Io and its neighboring moons result in time-varying tides from Jupiter that deform and heat Io's interior. Io is the best natural laboratory to study these intertwined processes, and it is a vitally important destination for addressing high priority, cross-cutting science investigations relevant to broad swaths of planetary science-from the Hadean Earth-Moon system when life emerged, to present-day potentially habitable ocean worlds, and distant exoplanets where conditions are even more extreme. Characterization of Io will guide future observations of both ocean worlds and exoplanetary targets. In a sense, Io is the uninhabitable world that teaches us how habitable worlds form and work.

Barriers to Melt Ascent in the Lithosphere of Io With Applications to Heat Pipe Formation

“…Further modeling is needed to evaluate the contributions of these three processes and the detailed development of the heat pipe cycle proposed here. Continued exploration of Io (Keane et al, 2021), including both Juno's extended mission and a dedicated mission such as the Io Volcano Observer (IVO; McEwen et al, 2014) is desirable to constrain the tidal love number to determine the fluid content of the interior, observe lithosphere deformation in real time, observe volcanic activity and eruption temperatures, and constrain the surface compositions beyond "silicate." This project was supported by a NASA Earth and Space Sciences Fellowship, Grant 80NSSC17K0486.…”