Search Publications
High-resolution infrared spectroscopy of ethane in Titan's stratosphere in the Huygens epoch
Sonnabend, G.; Kostiuk, T.; Schieder, R. +7 more
High-resolution infrared spectroscopy of ethane (C2H6) emission features formed in the stratosphere of Titan was collected on disc center at 11.74 µm wavelength (851 cm-1) on 15 January 2005 UT. The observations were obtained at the Subaru 8.2 m telescope of the National Astronomical Observatory of Japan on M…
Determination of local surface properties using Mars Express bistatic radar
Tyler, G. Leonard; Pätzold, Martin; Häusler, Bernd +1 more
Dual-frequency bistatic radar experiments were conducted with Mars Express at a rate of one to two per month during 2005. Each observation provided power measurements of orthogonally polarized surface echoes at one specular point; the ratio of these components yielded values of the dielectric constant in the range 2.0 < $\varepsilon$ < 4.0. …
Application of an orbital radar sounder model to detecting Martian polar subsurface features
Farrell, William M.; Xu, Yanbin; Cummer, Steven A.
A model to simulate the complete planetary orbital radar sounder problem is presented in this paper. The subsurface features and the ionosphere will not only bring ambiguity to the collected radar sounder data, but also critically affect instrument capabilities. These environmental uncertainties generate a compelling need for meaningful quantitati…
Huygens entry emission: Observation campaign, results, and lessons learned
de Pater, Imke; Lorenz, Ralph D.; Lemmon, Mark T. +8 more
An attempt was made to observe from Earth the emission from the shock layer and ``meteor trail'' formed during the Huygens probe's hypersonic entry into Titan's atmosphere. Although many observations were wiped out by weather or in-orbit failure, two observations constrain the emission from the entry. Several important lessons for future observati…
A new method to investigate hyperspectral image cubes: An application of the wavelet transform
Gendrin, Aline; Bibring, Jean-Pierre; Langevin, Yves +1 more
Data analysis of the Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA), the imaging spectrometer aboard Mars Express, necessitates the use of techniques able to extract the relevant information of large data sets. Numerous efficient algorithms have already been developed for similar purposes for terrestrial imaging spectro…
Flow discharge and sediment transport models for estimating a minimum timescale of hydrological activity and channel and delta formation on Mars
Kleinhans, M. G.
This paper summarizes state-of-the-art models for water flow and sediment transport and suggests implications for the sediment grain size distribution, transport process, and delta formation. The flow velocity in Martian outflow channels is commonly calculated from the Manning equation, which is dimensionally incorrect and masks the large uncertai…
Origin and evolution of a cold-based tropical mountain glacier on Mars: The Pavonis Mons fan-shaped deposit
Head, James W.; Marchant, David R.; Shean, David E.
Each of the large Tharsis Montes volcanoes in the equatorial region of Mars has an unusual Amazonian-aged fan-shaped deposit on its west-northwestern flank. On the basis of Viking Orbiter data, the origin of these deposits has been variously ascribed to volcanic, mass-wasting, tectonic, and glacial processes. Using new MGS and Odyssey data, combin…
Fluid lava flows in Gusev crater, Mars
Greeley, Ronald; Williams, David A.; Neukum, Gerhard +6 more
Rocks on the floor of Gusev crater are basaltic in composition, as determined from measurements by the Mars Exploration Rover, Spirit. On the basis of compositional data, models of the basaltic lavas at the time of their emplacement suggest viscosities of 2.3 to 50 Pa . s (dependent on the number of phenocrysts and vesicles that were present), whi…
Groundwater-controlled valley networks and the decline of surface runoff on early Mars
Harrison, Keith P.; Grimm, Robert E.
Fluvial erosion on early Mars was dominated by valley networks created through a combination of groundwater processes and surface runoff. A reduced greenhouse effect due to CO2 loss, together with a declining geothermal heat flux, promoted the growth of a cryosphere and a Hesperian hydrologic regime dominated by outflow channel formatio…
Jupiter Thermospheric General Circulation Model (JTGCM): Global structure and dynamics driven by auroral and Joule heating
Waite, J. H.; Gladstone, G. R.; Bougher, S. W. +1 more
A growing multispectral database plus recent Galileo descent measurements are being used to construct a self-consistent picture of the Jupiter thermosphere/ionosphere system. The proper characterization of Jupiter's upper atmosphere, embedded ionosphere, and auroral features requires the examination of underlying processes, including the feedbacks…