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Spacecraft outgassing observed by the BepiColombo ion spectrometers
  • +19
  • Markus Fraenz,
  • Mathias Rojo,
  • Thomas Cornet,
  • Lina HADID,
  • Yoshifumi Saito,
  • Nicolas André,
  • Ali Varsani,
  • Daniel Schmid,
  • Harald Krueger,
  • Norbert Krupp,
  • Dominique Delcourt,
  • Bruno Katra,
  • Yuki Harada,
  • Shoichiro Yokota,
  • Christophe Verdeil,
  • Sae Aizawa,
  • Anna Milillo,
  • Stefano Orsini,
  • Valeria Mangano,
  • Björn Fiethe,
  • Johannes Benkhoff,
  • Go Murakami
Markus Fraenz
Max-Planck-Institute for Solar System Research

Corresponding Author:[email protected]

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Mathias Rojo
Institut de Recherche en Astrophysique et Planétologie, CNRS-Université Toulouse III-CNES
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Thomas Cornet
European Space Agency
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Yoshifumi Saito
Institute of Space & Astronautical Science
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Nicolas André
Institut de Recherche en Astrophysique et Planétologie, CNRS-Université Toulouse III-CNES
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Ali Varsani
Austrian Academy of Sciences
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Daniel Schmid
Space Research Institute Graz (IWF), Austrian Academy of Sciences (OeAW)
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Harald Krueger
Max Plank Institut fuer Sonnensystemforschung, Goettingen, Germany
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Norbert Krupp
Max-Planck-Institut fur Sonnensystemforschung
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Dominique Delcourt
CNRS Orleans, France
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Bruno Katra
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Yuki Harada
Kyoto University
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Shoichiro Yokota
Osaka University
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Christophe Verdeil
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Sae Aizawa
University of Pisa
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Anna Milillo
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Stefano Orsini
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Valeria Mangano
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Björn Fiethe
TU Braunschweig
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Johannes Benkhoff
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Go Murakami
Japan Aerospace Exploration Agency
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During the first flyby of the BepiColombo composite spacecraft at Mercury in October
2021 ion spectrometers observed two intense spectral lines with energies between 10 and
70eV. The spectral lines persisted also at larger distances from Mercury and were ob-
served again at lower intensity during cruise phase in March 2022 and at the second and
third Mercury flyby as a single band. The ion composition indicates that water is the
dominant gas source. The outgassing causes the composite spacecraft to charge up to
a negative potential of up to -50V. The distribution and intensity of the lower energy
signal depends on the intensity of low energy electron fluxes around the spacecraft which
again depend on the magnetic field orientation. We interpret the observation as being
caused by water outgassing from different source locations on the spacecraft being ion-
ized in two different regions of the surrounding potential. The interpretation is confirmed
by two dimensional particle-in-cell simulations.
07 Sep 2023Submitted to ESS Open Archive
11 Sep 2023Published in ESS Open Archive