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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Kofman, Wlodek W.
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (21/21 displayed)
- 2017 Interior of 67P/C-G comet as seen by CONSERT bistatic radar on Rosetta
- 2016Cosmochemical implications of CONSERT permittivity characterization of 67P/CG
- 2016An interpretation of the CONSERT and SESAME-PP results based on new permittivity measurements of porous water ice and ice-basaltic/organic dust mixtures suggests an increase of porosity with depth in 67P
- 2016Looking at Comet 67P Sub-surface in the Vicinity of Abydos
- 2016Characterizing the interior of 67P in the vicinity of Abydos
- 2016Cosmochemical implications of CONSERT permittivity characterization of 67P/C-G
- 2016Heterogeneities of 67P nucleus seen by CONSERT in the vicinity of Abydos
- 2016Mineralogical Implications of CONSERT Permittivity Characterization of 67P
- 2016Effect of meter-scale heterogeneities inside 67P nucleus on CONSERT data
- 2015Insights gained from Data Measured by the CONSERT Instrument during Philae's Descent onto 67P/C-G's surface
- 2015Broadband permittivity measurements on porous planetary regoliths simulants, in relation with the Rosetta mission to 67P/C-G
- 2015CONSERT Radar Investigations of the Shallow Subsurface of Comet 67P, in the Vicinity of the Philae Lander
- 2015Broadband Permittivity Measurements on Porous Planetary Soil Simulants, in Relation with the Rosetta Mission
- 2015The CONSERT Instrument during Philae's Descent onto 67P/C-G’s surface: Insights on Philae’s Attitude and the Surface Permittivity Measurements at the Agilkia-Landing-Site
- 2015Revealing the Possible Existence of a Near-Surface Gradient in Local Properties of 67P/Churyumov-Gerasimenko Nucleus Through CONSERT Measurements
- 2015The interior of 67P/C-G nucleus revealed by CONSERT measurements and simulations
- 2014Revealing the properties of Chuyurmov-Gerasimenko's shallow sub-surface through CONSERT's measurements at grazing angles
- 2009Comet nuclei primordial aggregation effects on their internal structure
- 2008Imaging of the Internal Structure of Comet 67P/Churyumov-Gerasimenko from Radiotomography CONSERT Data (Rosetta Mission) through spectral techniques
- 2008Comet nuclei aggregation and thermal simulations to prepare the Rosetta mission
- 2007Imaging of the Internal Structure of Comet 67P/Churyumov-Gerasimenko from Radiotomography CONSERT Data by Using Grid Computing Techniques (Rosetta Mission).
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document
Broadband permittivity measurements on porous planetary regoliths simulants, in relation with the Rosetta mission to 67P/C-G
Abstract
The Rosetta mission has successfully rendezvous comet 67P/Churyumov-Gerasimenko (hereafter 67P) last year and landed Philae module on its nucleus on 12 November it 2014. Among instruments onboard Rosetta, MIRO [1], composed of two radiometers, with receivers at 190 GHz and 563 GHz (center-band), is dedicated to the measurements of the subsurface and surface brightness temperatures. These values depend on the complex relative permittivity (hereafter permittivity) with ε' and ε " the real and imaginary parts. The permittivity of the material depends on frequency, bulk density/porosity, composition and temperature [2]. Considering the very low bulk density of 67P nucleus (about 450 kg.m-3 [3]) and the suspected presence of a dust mantle in many areas of the nucleus [4], investigations on the permittivity of porous granular samples are needed to support the interpretation of MIRO data, as well as of other microwave experiments onboard Rosetta, e.g. CONSERT [5], a bistatic penetrating radar working at 90 MHz. We have developed a programme of permittivity measurements on porous granular samples over a frequency range from 50 MHz to 190 GHz under laboratory conditions (e.g. [6] and [7]). We present new results obtained on JSC-1A lunar soil simulant and ashes from Etna. The samples were split into several sub-samples with different size ranges covering a few to 500 µm. Bulk densities of the sub-samples were carefully measured and found to be in the 800-1400 kg.m-3 range. Sub-samples were also dried and volumetric moisture content was found to be below 0.6%. From 50 MHz to 6 GHz and at 190 GHz, the permittivity has been determined, respectively with a coaxial cell and with a quasi-optical bench mounted in transmission, both connected to a vector network analyzer. The results demonstrate the dispersive behaviours of ε' between 50 MHz and 190 GHz. Values of ε' remain within the 3.9-2.6 range for all sub-samples. At CONSERT frequency, ε " is within the 0.01-0.09 range for all sub-samples. The single-relaxation Debye model fits relatively well the global behaviour of ε' over the frequency range, thus validating the experimental setups and measurements obtained. Furthermore, results confirm that ε' decreases quasi-linearly with the decreasing bulk density at any frequency, as expected by the mixing formulae. Taking into account possible temperature variations within 67P nucleus [8] and the linear decrease of the permittivity with the temperature, as measured by [9] on JSC-1A sample, these results indicate that, on the near-surface of 67P covered by a free-ice dust mantle at the frequencies of MIRO and CONSERT