Sebastian Walter

Planetary imaging: calibration, processing, mapping, visualisation.

About

Research Associate in Planetary Sciences and Remote Sensing at Freie Universität Berlin, where I have worked since 2004 on geometric calibration and pipeline engineering for spaceborne optical instruments. My work spans the full chain from raw detector data to calibrated, co-registered science products and their dissemination to the broader community.

I serve as Co-Investigator on active ESA and NASA imaging missions, contributing to instrument operations, in-flight calibration, and data dissemination.

Outside work I'm more down to earth — navigating my boat on Berlin's waters rather than the solar system.

Selected Work

HRSC / Mars Express I've worked on the HRSC imaging chain since the early Mars Express mission phase — multi-orbit bundle adjustment, in-flight calibration, and the global seamless mosaics the team disseminates.
Koregistrierung (2022–2026, lead) A co-registration pipeline I led that couples CTX imagery to HRSC global datasets, feeding residuals back into camera orientation refinement.
CTX in-flight calibration I worked out the updated radiometric calibration for the Mars Reconnaissance Orbiter Context Camera and published the result in Earth and Space Science (2024).
Mastcam-Z / Mars 2020 Perseverance Operations and image processing for the Mastcam-Z camera, plus multispectral maps and a virtual-reality visualisation of the Jezero crater landing site — try the interactive map at maps.planet.fu-berlin.de/jezero.
JANUS / JUICE A bespoke imagery database for the JANUS narrow-angle camera on the Jupiter Icy Moons Explorer — Django and PostgreSQL/PostGIS on the backend, React/Vite plus an OpenLayers mapping frontend.

Publications

Barnes, R., Gupta, S., […], Walter, S., Hickman-Lewis, K., Farley, K., 2026. Intrusion-Induced Forced Folding Model for the Origin of Séítah Formation Domes on the Jezero Crater Floor, Mars. Journal of Geophysical Research: Planets 131, e2025JE009463.
doi:10.1029/2025JE009463
Walter, S., 2025. Life cycle of planetary images from Mars orbit: From raw data processing to high-level data dissemination. Dissertation, Freie Universität Berlin.
doi:10.17169/refubium-47546
Ovchinnikova, A., Jaumann, R., Walter, S.H.G., Gross, C., Zuschneid, W., Postberg, F., 2025. A modeling approach for water and sediment transport in Jezero crater on Mars based on new geomorphological evidence. Icarus 426, 116349.
doi:10.1016/j.icarus.2024.116349
Walter, S.H.G., Aye, K.-M., Jaumann, R., Postberg, F., 2024. Mars Reconnaissance Orbiter Context Camera Updated In-Flight Calibration. Earth and Space Science 11, e2023EA003491.
doi:10.1029/2023EA003491
Jaumann, R., […], Walter, S.H.G., Hiesinger, H., 2024. Geological Record of Water and Wind Processes on Mars as Observed by the Mars Express High Resolution Stereo Camera. Space Science Reviews 220, 45.
doi:10.1007/s11214-024-01076-z
Orgel, C., […], Walter, S.H.G., 2024. Characterization of High-priority Landing Sites for Robotic Exploration Missions in the Apollo Basin, Moon. The Planetary Science Journal 5, 29.
doi:10.3847/PSJ/ad1108
Quantin-Nataf, C., […], Walter, S.H.G., […], 2023. The Complex Exhumation History of Jezero Crater Floor Unit and its implication for Mars Sample Return. Journal of Geophysical Research: Planets.
Walter, S.H.G., Munteanu, R.R.C., Aye, M., 2023. CTX in-flight calibration and data dissemination. EGU General Assembly 2023.
doi:10.5194/egusphere-egu23-13656
Walter, S.H.G., Gross, C., Neesemann, A., Munteanu, R., Jaumann, R., Postberg, F., Bell, J., 2022. An Interactive Virtual Hiking Map for Jezero Crater, the Mars 2020 Perseverance Rover Landing Site. European Planetary Science Congress 16, EPSC2022-32.
doi:10.5194/epsc2022-32
Walter, S.H.G., Neesemann, A., Gwinner, K., Michael, G.G., Jaumann, R., Postberg, F., 2022. Coregistering Mars Reconnaissance Orbiter Context Camera Images to Mars Express High Resolution Stereo Camera Global Datasets. European Planetary Science Congress 16, EPSC2022-601.
doi:10.5194/epsc2022-601
Bell, J.F., […], Walter, S.H.G., […], 2022. Geological, multispectral, and meteorological imaging results from the Mars 2020 Perseverance rover in Jezero crater. Science Advances 8.
doi:10.1126/sciadv.abo4856
Klenner, F., Umair, M., Walter, S.H.G., Khawaja, N., Hillier, J., Nölle, L., Zou, Z., Napoleoni, M., Sanderink, A., Zuschneid, W., Abel, B., Postberg, F., 2022. Developing a Laser Induced Liquid Beam Ion Desorption Spectral Database as Reference for Spaceborne Mass Spectrometers. Earth and Space Science 9.
doi:10.1029/2022EA002313
Walter, S.H.G., Michael, G.G., Gwinner, K., Jaumann, R., 2020. Seamless albedo mosaic maps from Mars Express High Resolution Stereo Camera (HRSC) imagery. European Planetary Science Congress 14, EPSC2020-18.
doi:10.5194/epsc2020-18
Walter, S.H.G., Muller, J.-P., Sidiropoulos, P., Tao, Y., Gwinner, K., et al., 2018. The Web-Based Interactive Mars Analysis and Research System for HRSC and the iMars Project. Earth and Space Science 5, 308–323.
doi:10.1029/2018EA000389
Michael, G., Walter, S.H.G., Kneissl, T., Zuschneid, W., Gross, C., McGuire, P.C., Dumke, A., Schreiner, B., van Gasselt, S., Gwinner, K., Jaumann, R., 2016. Systematic processing of Mars Express HRSC panchromatic and colour image mosaics: Image equalisation using an external brightness reference. Planetary and Space Science 121, 18–26.
doi:10.1016/j.pss.2015.12.002

Elsewhere

Contact

sebastian@swalter.eu