- University of Bern, Physikalisches Institut, Weltraumforschung und Planetologie, Switzerland (brian.magee@unibe.ch)
We present preliminary results of modelling Europa’s exosphere and how this work will aid preparation of the science teams for the mass spectrometer instruments currently on their way to investigate the icy moon.
Jupiter’s icy moon Europa is one of the most intriguing bodies in the Solar System due to its astrobiological potential and will be explored in the 2030’s by both ESA’s Jupiter Icy Moons Explorer (JUICE) and NASA’s Europa Clipper missions. Europa’s tenuous atmosphere will be sampled in-situ by the Neutral gas and Ion Mass spectrometer (NIM) [1] onboard JUICE and the MAss Spectrometer for Planetary EXploration (MASPEX) [2] onboard Europa Clipper, providing high mass resolution measurements of the observed chemical composition. These observations will allow deduction of Europa’s surface composition and processes as well as inferences about its subsurface ocean.
Previous models of Europa show the dominance of O2 near the surface with extended populations of H2 and H2O at higher altitudes [3,4]. Others have focused on potential plumes, contrasting between different source mechanisms [5], and demonstrating the localized and global effects of an Enceladus-like plume source on the otherwise sputtered exosphere [4].
Our model focuses on the primary source and loss processes of Europa’s exosphere including sublimation and sputtering of the surface ice, photochemistry and ionization. For our model we utilize the open-source Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code [6]. This code employs the Direct Simulation Monte Carlo (DSMC) method [7] to model the behaviour of gas particle interactions, allowing an investigation of the extent of the collisional atmosphere and comparisons to fully collision-less models [3].
Finally, we show how our model, including future enhancements such as coupling with DSMC plume models in the same code framework [8], can tie directly to expected observational data via instrument data models of the mass spectrometers. We thus highlight the role that models may play in both interpreting mission data and informing instrument science operations during the JUICE and Europa Clipper mission lifetimes.
Acknowledgement:
The authors acknowledge the financial support of the SNSF under SNSF starting grant 218336.
References:
[1] Föhn, M., et al. (2021), IEEE Aerospace Conference (50100). IEEE, 1-14.
[2] Waite Jr, J. H., et al. (2024). Space Science Reviews, 220.3, 30. https://doi.org/10.1007/s11214-024-01061-6
[3] Vorburger, A., and Wurz, P. (2018). Icarus, 311, 135-145. https://doi.org/10.1016/j.icarus.2018.03.022
[4] Teolis, B. D., et al. (2017). Icarus, 284, 18-29. http://dx.doi.org/10.1016/j.icarus.2016.10.027
[5] Vorburger, A., and Wurz, P. (2021). J. Geophys. Res. Space Phys., 126(9). https://doi.org/10.1029/2021JA029690
[6] S. J. Plimpton, et al. (2019). Physics of Fluids 31, 086101. https://doi.org/10.1063/1.5108534
[7] Bird, G. A. (1994). Molecular gas dynamics and the direct simulation of gas flows.
[8] Mosimann, T., et al. (2025). EPSC-DPS Joint Meeting 2025. https://doi.org/10.5194/epsc-dps2025-899
How to cite: Magee, B., Vorburger, A., Schlarmann, L., and Mosimann, T.: Europa’s exosphere - preparation for mass spectrometry investigation at Jupiter’s icy moon, Europlanet Science Congress 2026, The Hague, The Netherlands, 7–11 Sep 2026, EPSC2026-930, https://doi.org/10.5194/epsc2026-930, 2026.
