Preprints
https://doi.org/10.5194/egusphere-2026-2064
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/egusphere-2026-2064
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
22 Apr 2026
| 22 Apr 2026
Status: this preprint is open for discussion and under review for Annales Geophysicae (ANGEO).
Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA). IV. Antenna pointing and beam characterisation
Abstract. The Submillimetre Wave Instrument (SWI) onboard the Jupiter Icy Moons Explorer (Juice) spacecraft consists of a 29 cm off-axis paraboloid antenna and two double-sideband heterodyne receivers operating in the frequency ranges of 530–638 and 1066–1286 GHz. This instrument is designed to study Jupiter’s atmosphere and the exospheres of the Galilean moons.
We used the Lunar-Earth-Gravity-Assist (LEGA) data from August 2024 to characterise this antenna using several SWI observations pointing towards the Earth. The data analysis of the LEGA observations dedicated to the antenna beam allows us to characterise the antenna beam Full Width at Half Maximum (FWHM), sidelobes, absolute pointing and receiver coalignement. Moreover, an estimate of the calibration efficiency factor has been obtained.
How to cite. Moreno, R., Rezac, L., Formánek, T., Cavalié, T., Jarchow, C., Lellouch, E., Hartogh, P., Murk, A., Kotiranta, M., Carrasco Gallardo, A., Goodyear, S., Schulz-Ravanbakhsh, A., Dabrowski, B., Herpin, F., Kasai, Y., Murtagh, D., Olberg, M., Rengel, M., Sagawa, H., Szutowicz, S., and Wirström, E.: Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA). IV. Antenna pointing and beam characterisation, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2026-2064, 2026.
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LIRA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
Ladislav Rezac
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Tomáš Formánek
LIRA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
Thibault Cavalié
Univ. Bordeaux, CNRS, LAB, UMR 5804, F-33600 Pessac, France
Christopher Jarchow
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Emmanuel Lellouch
LIRA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
Paul Hartogh
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Axel Murk
Institute of Applied Physics, University of Bern, Switzerland
Mikko Kotiranta
Institute of Applied Physics, University of Bern, Switzerland
Alberto Carrasco Gallardo
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Samuel Goodyear
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Ali Schulz-Ravanbakhsh
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Borys Dabrowski
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Fabrice Herpin
Univ. Bordeaux, CNRS, LAB, UMR 5804, F-33600 Pessac, France
Yasuko Kasai
National Institute of Information and Communications Technology, Tokyo, Japan
Institute of Science Tokyo, Tokyo, Japan
Donal Murtagh
Department of Physics and Astronomy, Chalmers University of Technology, Sweden
Michael Olberg
Department of Physics and Astronomy, Chalmers University of Technology, Sweden
Miriam Rengel
Max-Planck-Institute for Solar System Research, Göttingen, Germany
Hideo Sagawa
Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555, Japan
Slawomira Szutowicz
Centrum Badań Kosmicznych Polskiej Akademii Nauk, Bartycka 18A, Warsaw, Poland
Eva Wirström
Department of Physics and Astronomy, Chalmers University of Technology, Sweden
Short summary
The Submillimetre Wave Instrument (SWI) onboard the Jupiter Icy Moons Explorer (Juice) spacecraft consists of a 29 cm antenna and two radio receivers operating at submillimeter wavelength. This instrument is designed to study Jupiter's atmosphere and the thin atmospheres of its moons.
We used Earth observations obtained during the Lunar-Earth-Gravity-Assist (LEGA) . This data analysis allows us to characterise the antenna beam and pointing corrections.
The Submillimetre Wave Instrument (SWI) onboard the Jupiter Icy Moons Explorer (Juice)...