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| Titel |
DOTS: A High Resolution Orbitrap Mass Spectrometer for In Situ Analysis of the surface samples of Airless Planetary Bodies |
| VerfasserIn |
Christelle Briois, Roland Thissen, Cécile Engrand, Kathrin Altwegg  , Abdel Bouabdellah, Amirouche Boukrara, Nathalie Carrasco, Claude Chapuis, Hervé Cottin, Eberhard Grün, Noël Grand, Hartmut Henkel, Sascha Kempf, Jean-Pierre Lebreton, Alexander A. Makarov, Frank Postber, Ralf Srama, Jürgen Schmidt, Cyril Szopa, Laurent Thirkell, Gabriel Tobie, Peter Wurz, Mikhail Yu Zolotov |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250084889
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| Zusammenfassung |
| The dust detectors on board the Ulysses and Galileo spacecraft have shown that the Galilean
satellites are surrounded by clouds of sub-micrometer size grains generated by impacts of
interplanetary (micro-) meteoroids [1, 2]. In situ chemical analysis from orbit of these
ballistic grains ejected from the surface of airless bodies provides a unique opportunity to
remotely access the chemical composition of the Jovian moons’ surface and subsurface. For
Saturn, in situ identification by the Cassini Dust Analyzer (CDA) of sodium in icy
grains in the E-Ring and in Enceladus plumes have proven a subsurface liquid water
reservoir inside Enceladus [3, 4]. Noticeably, this was not accessible to other in situ or
traditional remote sensing techniques. In situ measurements, either during a flyby or
from orbit, of grains ejected from the surface, or emerging from the subsurface, of
an airless body is a powerful tool to remotely study its surface composition and
the nature of its geological activity. Crucial constraints on habitability can thus be
determined. Our consortium of laboratories, in collaboration with Thermo Fischer
Scientific [5, 6], is currently developing a high mass resolution Fourier Transform (FT)
Orbitrap-based mass spectrometer optimized for in situ analysis of dust and icy grains in
the environment of Solar System airless bodies. This new generation of dust mass
spectrometer was studied in the framework of the Europa Jupiter System Mission
(EJSM) instrument study in 2010-2012 and proposed in response to ESA’s AO
for the JUpiter ICy moons Explorer (JUICE) mission [7]. This mass analyser can
provide very high mass resolution analysis (M/ΔM reaching 50 000 at m/z 50 Da).
DOTS would allow identification of elemental and molecular species with excellent
accuracy, in the 20-1000 Da mass range. In the context of the JUICE mission, DOTS
would provide decisive information on the surface composition and on the putative
liquid oceans in the subsurface of Ganymede, Europa and Callisto. The high mass
resolution capability of DOTS is especially beneficial for heavy species, as the mass
resolving power (M/ΔM) of DOTS remains above 10 000 up to m/z=1 000 Da.
Isotopic ratios can also be measured with DOTS, which would give insights into
the origin and the processing of the parent molecules inside the grains. DOTS is
designed with a dual polarity that allows for the detection of both negative and positive
ions, best suited for both the detection of major rock forming elements (minerals,
mostly cations) and organic compounds (preferentially anions in oxidizing medium).
The recently discovered outer rings of Uranus [8] present striking similarity with
Saturn’s E ring, which is now considered as the result of ice volcanic activity of
Enceladus. If a similar process is at work, this outer blue ring of Uranus could result
from meteoroid impacts continually blasting dust off the surface of Mab (small
embedded moon on the outermost blue ring) [9]. A DOTS-like instrument would be of
great value to study the nature of this ring, in the context of a future mission to
Uranus.
References
[1] Krüger, H. et al. (1999). Nature, 399, 558–560. [2] Krivov, A.V. et al. (2003) PSS
51, 251–269. [3] Postberg, F. et al. (2009) Nature, 459, 1098-1101. [4] Postberg,
F. et al. (2011) Nature, 474, 620-622. [5] Makarov, A. (2000) Anal. Chem., 72,
1156-1162, [6] Makarov, A. et al. (2005) Anal. Chem., 78, 2113. [7] Dust OrbiTrap
Sensor - DOTS proposal, PI Thissen R. (October 2012). [8] dePater I. et al. (2006)
Science, 392, 92-94, [9] Showalter M.R. and Lissauer J.J. (2006) Science, 311,
973-977.
Acknowledgements
We thank the CNES (R&T SU-0003-039) for financial support. |
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