Search Publications
Ptolemy operations and results during the Lutetia flyby
Andrews, D. J.; Leese, M. R.; Zarnecki, J. C. +6 more
The September 5th 2008 Rosetta flyby of asteroid 2867 Šteins raised tantalising questions concerning the possibility of outgassing and extant exospheres surrounding small bodies within the asteroid belt. With this in mind and recognising the size and composition of asteroid 21 Lutetia it was decided to attempt a detection of such possible outgassi…
In situ mass spectrometry during the Lutetia flyby
Wurz, P.; Altwegg, K.; Balsiger, H. +12 more
During the Rosetta flyby at asteroid Lutetia the ROSINA instrument tried to detect a thin exosphere of the asteroid. Although the instrument is sensitive enough to detect even very tenuous gases at a density level of 1 cm-3 the Lutetia exosphere could not be unambiguously detected due to spacecraft outgassing, which was not constant bec…
The Huygens surface science package (SSP): Flight performance review and lessons learned
Lorenz, R. D.; Leese, M. R.; Hathi, B. +1 more
The Surface Science Package (SSP) was one of six instruments flown onboard the Huygens probe to Titan, the largest moon of Saturn, in the framework of the NASA/ESA/ASI Cassini-Huygens mission (Matson et al., 2002). The SSP operated throughout the probe's descent and after landing on Titan on 14th January 2005. This paper reviews scientific results…
Limb Darkening study using Venus nightside infrared spectra from VIRTIS-Venus Express data
Drossart, Pierre; Longobardo, Andrea; Palomba, Ernesto +3 more
The Limb Darkening (LD) effect consists in an attenuation of the measured radiance at increasing emergence angles, due to the larger portion of the atmosphere traversed by the radiation observed at higher emergence angles. The behaviour of radiance emerging with atmosphere as function of the emergence angle (i.e., the Limb Darkening Function) is r…
The light curve of asteroid 21 Lutetia measured by VIRTIS-M during the Rosetta fly-by
Erard, S.; Capaccioni, F.; Coradini, A. +7 more
On 10 July 2010, the Rosetta spacecraft encountered the asteroid 21 Lutetia on its way to the comet 67P/Churyumov-Gerasimenko. This was the second of two planned asteroid fly-bys performed by the probe, the first fly-by being with the much smaller asteroid 2867 Steins in September 2008. The VIRTIS imaging spectrometer (angular resolution 0.250 mra…
Optical depth of the Martian atmosphere and surface albedo from high-resolution orbiter images
Thomas, N.; Hoekzema, N. M.; Stenzel, O. J. +2 more
In this paper we describe and evaluate the so-called shadow method. This method can be used to estimate the optical depth of the Martian atmosphere from the differences in brightness between shadowed and sunlit regions observed from an orbiter. We present elaborate and simplified versions of the method and analyze the capabilities and the sources …
Temperature and grain size dependence of near-IR spectral signature of crystalline water ice: From lab experiments to Enceladus' south pole
Le Mouélic, Stéphane; Taffin, Cécile; Grasset, Olivier +3 more
An experimental facility has been set up to acquire infrared spectra of pure water ices with controlled grain sizes ranging from 80 to 700 µm and temperatures ranging from 80 to 140 K at 10-2 mbar. Forty-seven near IR spectra (1.0-5.0 µm), selected among the total acquired spectra, permit us to determine how spectral charact…
On the unmixing of MEx/OMEGA hyperspectral data
Schmidt, Frédéric; Daglis, Ioannis A.; Themelis, Konstantinos E. +3 more
This paper presents a comparative study of three different types of estimators used for supervised linear unmixing of two MEx/OMEGA hyperspectral cubes. The algorithms take into account the constraints of the abundance fractions, in order to get physically interpretable results. Abundance maps show that the Bayesian maximum a posteriori probabilit…
The abundance of H2 in Titan's troposphere from the Cassini CIRS investigation
Gautier, Daniel; Kim, Sang Joon; Courtin, Régis +1 more
We derived the mole fraction of H2 in the troposphere of Titan from an analysis of the H2-N2 dimer S0(0) rotational transition seen near 355 cm-1 in spectra recorded by the Composite Infra-Red Spectrometer (CIRS) on the Cassini spacecraft between March 2006 and February 2007. We find a globall…
Interpretation of COSAC mass spectrometer data acquired during Rosetta's Lutetia fly-by 10 July 2010
McKenna-Lawlor, Susan; Szopa, Cyril; Roll, Reinhard +6 more
On 10 July 2010 the Rosetta spacecraft flew-by asteroid Lutetia. At that time all the mass spectrometers in the payload of the Philae Lander capable of gas analysis were in operation. Among these, the COSAC (Cometary Sampling and Composition) experiment is a gas-chromatograph mass spectrometer which was switched on twice during the fly-by, once 3 …