STUDYING THE FORMATION, EVOLUTION, AND HABITABILITY OF THE GALILEAN SATELLITES

Highly sensitive, high-mass resolution mass spectrometry is an important in situ tool for the study of the formation, evolution, and habitability of the Galilean satellites. Organic molecules are essential indicators of potential habitability, while the isotopes and noble gases are important determinants of satellite origin and evolution—both keys to understanding the chemical pathways in Jupiter’s icy moons. Building on Cassini’s Ion and Neutral Mass Spectrometer methodology, new technologies have been developed that boost mass resolution and detection sensitivity to unprecedented levels in comparison with previous flight instruments. High mass resolution (m/Δm >20,000) and sensitivity of parts per 10⁹ (ppb) enable identification of complex organic molecules and stable isotopic ratios in key volatiles (H, O, S) and accurate measurement of the trace noble gases argon, krypton, and xenon at carbonaceous chondrite concentrations. This new technology offers, through direct sampling of atomic and molecular species in the sputter-derived or (if present) outgassed exosphere, a powerful and independent capability to determine or constrain regional and global surface compositions. In this talk we detail the science objectives, develop the rationale for the measurement requirements, and describe potential instrument/mission methodologies for studying the formation, evolution, and habitability of the Galilean satellites. We emphasize our studies of Ganymede and Europa as described in the recently selected JUICE mission and the proposed Europa Clipper mission.