Search Publications
Modeling polarimetric radar scattering from the lunar surface: Study on the effect of physical properties of the regolith layer
Heggy, Essam; Wieczorek, Mark A.; Fa, Wenzhe
A theoretical model for radar scattering from the lunar regolith using the vector radiative transfer theory for random media has been developed in order to aid in the interpretation of Mini-SAR data from the Chandrayaan-1 and Lunar Reconnaissance Orbiter missions. The lunar regolith is represented as a homogeneous fine-grained layer with rough upp…
Dark aeolian sediments in Martian craters: Composition and sources
Poulet, F.; Jaumann, R.; Tirsch, D. +1 more
Our research focuses on the mineralogical characteristics of dark sediment deposits in Martian craters (dunes, dune fields, and sand sheets) and their local sediment sources, carried out on the basis of 70 selected localities. Morphological analyses reveal dark layers exposed in a number of crater walls, showing indications of material transport f…
New near-IR observations of mesospheric CO2 and H2O clouds on Mars
Bibring, Jean-Pierre; Gondet, Brigitte; Vincendon, Mathieu +2 more
Carbon dioxide clouds, which are speculated by models on solar and extra-solar planets, have been recently observed near the equator of Mars. The most comprehensive identification of Martian CO2 ice clouds has been obtained by the near-IR imaging spectrometer OMEGA. CRISM, a similar instrument with a higher spatial resolution, cannot de…
Remote compositional analysis of lunar olivine-rich lithologies with Moon Mineralogy Mapper (M3) spectra
Mustard, John F.; Clark, Roger N.; Head, James W. +10 more
A systematic approach for deconvolving remotely sensed lunar olivine-rich visible to near-infrared (VNIR) reflectance spectra with the Modified Gaussian Model (MGM) is evaluated with Chandrayaan-1 Moon Mineralogy Mapper (M3) spectra. Whereas earlier studies of laboratory reflectance spectra focused only on complications due to chromite …
Areas of enhanced ionization in the deep nightside ionosphere of Mars
Gurnett, D. A.; Němec, F.; Morgan, D. D. +1 more
We present observations of areas of enhanced ionization located in the deep nightside ionosphere of Mars as observed by Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board the Mars Express spacecraft. Oblique ionospheric echoes coming from the same region observed during several consecutive MARSIS measurements enable us t…
Unique spinel-rich lithology in lunar meteorite ALHA 81005: Origin and possible connection to M3 observations of the farside highlands
Treiman, Allan H.; Gross, Juliane
A new lunar rock type, rich in (Mg, Fe)Al spinel and lacking abundant olivine and pyroxene, was recently detected by near-infrared reflectance spectroscopy by the M3 instrument on the Chandrayaan-1 spacecraft. No such material has been described from lunar rocks, either returned samples or meteorites. Here we describe a fragment of rock…
The nature of lunar volatiles as revealed by Mini-RF observations of the LCROSS impact site
Patterson, G. W.; Neish, C. D.; Bussey, D. B. J. +4 more
On 9 October 2009 the Lunar Crater Observation and Sensing Satellite (LCROSS) impacted Cabeus crater, located near the south pole of the Moon. Prior to that impact, the Mini-RF instruments on ISRO's Chandrayaan-1 and NASA's Lunar Reconnaissance Orbiter (LRO) obtained S band (12.6 cm) synthetic aperture radar images of the impact site at 150 and 30…
Influence of the scar geometry on landslide dynamics and deposits: Application to Martian landslides
Lucas, Antoine; Mège, Daniel; Mangeney, Anne +1 more
Landslides dynamics prediction remains difficult in spite of a considerable number of studies. The runout distance is widely used in analysis of landslide dynamics and in the calibration of the rheological parameters involved in numerical modeling. However, the unknown impact of the significant uncertainty in the shape of the initial released mass…
Observations of thermal tides in the middle atmosphere of Mars by the SPICAM instrument
Montmessin, F.; Bertaux, J. -L.; Withers, Paul +1 more
We use vertical profiles of Martian atmospheric density, pressure, and temperature from the Mars Express SPICAM UV spectrometer to study thermal tides in the poorly studied middle atmosphere region at 70-120 km. Here we show that nonmigrating tides cause zonal pressure variations of tens of percent and zonal temperature variations on the order of …
Modeling radar scattering from icy lunar regoliths at 13 cm and 4 cm wavelengths
Heggy, Essam; Thompson, Thomas W.; Ustinov, Eugene A.
Two orbital synthetic aperture radars (SARs), the Chandrayaan-1 Mini-SAR (13 cm wavelength) and the Lunar Reconnaissance Orbiter (LRO) Mini-RF (13 and 4.2 cm wavelengths), have been imaging the lunar surface searching for ice deposits in the polar permanently shadowed areas. To understand the radar signatures of lunar polar ices, an empirical two-…