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What the ancient phyllosilicates at Mawrth Vallis can tell us about possible habitability on early Mars
Murchie, Scott L.; Bishop, Janice L.; Parente, Mario +5 more
Phyllosilicate deposits on Mars provide an opportunity to evaluate aqueous activity and the possibility that habitable environments may have existed during the Noachian period there. Analysis of hyperspectral visible/near-infrared (VNIR) Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) images has shown…
Mars impact ejecta in the regolith of Phobos: Bulk concentration and distribution
Head, James W.; Ramsley, Kenneth R.
The gravity of Mars and the observation of a thick Phobos regolith suggest that nearly all Phobos ejecta returns to Phobos and re-impacts on Phobos. Primary ejecta from Mars typically impacts Phobos at velocities of ~2-3 km/s and due to the low escape velocity from Phobos of ~4-10 m/s, ~95-99% of the secondary ejecta from Phobos is inserted into t…
Gypsum, opal, and fluvial channels within a trough of Noctis Labyrinthus, Mars: Implications for aqueous activity during the Late Hesperian to Amazonian
Weitz, Catherine M.; Grant, John A.; Bishop, Janice L.
We investigate in detail the morphology, mineralogy, and stratigraphy of light-toned deposits within one trough of Noctis Labyrinthus, centered at -6.8°N, 261.1°E. CRISM spectra taken from light-toned layered deposits in the northern portion of the trough exhibit absorptions around 1.41, 1.92 and 2.21 µm, consistent with mixtures of opal and…
Co-registration of laser altimeter tracks with digital terrain models and applications in planetary science
Oberst, J.; Gläser, P.; Haase, I. +1 more
We have derived algorithms and techniques to precisely co-register laser altimeter profiles with gridded Digital Terrain Models (DTMs), typically derived from stereo images. The algorithm consists of an initial grid search followed by a least-squares matching and yields the translation parameters at sub-pixel level needed to align the DTM and the …
Mars surface phase function constrained by orbital observations
Vincendon, Mathieu
The bidirectional photometric properties of the surface of Mars describe how remote measurements of surface reflectance can be linked to hemispherical albedo used for energy balance calculations. A simple Lambert's law is frequently assumed for global data processing, even though several local studies have revealed the complexity of Mars surface p…
Scaling relationships and concavity of small valley networks on Mars
Fassett, Caleb I.; Penido, Julita C.; Som, Sanjoy M.
Valley networks are widely interpreted as the preserved erosional record of water flowing across the martian surface. The manner in which valley morphometric properties scale with drainage area has been widely examined on Earth. Earlier studies assessing these properties on Mars have suggested that martian valleys are morphometrically distinct fro…
The origin of Phobos grooves from ejecta launched from impact craters on Mars: Tests of the hypothesis
Head, James W.; Ramsley, Kenneth R.
The surface of the martian moon Phobos is characterized by parallel and intersecting grooves that bear resemblance to secondary crater chains observed on planetary surfaces. Murray (2011) has hypothesized that the main groove-forming process on Phobos is the intersection of Phobos with ejecta from primary impact events on Mars to produce chains of…
The Hohmann-Parker effect measured by the Mars Science Laboratory on the transfer from Earth to Mars: Consequences and opportunities
Frahm, R. A.; Wimmer-Schweingruber, R. F.; Christian, E. R. +33 more
We show that a spacecraft launched from Earth towards Mars following a Hohmann minimum energy transfer trajectory has a strong tendency to remain well-connected magnetically to Earth, in the early phase of the transfer, or to Mars in the late phase, via the Parker spiral magnetic field. On the return trip, the spacecraft would remain reasonably we…
Variability in ionospheric total electron content at Mars
Withers, Paul; Kofman, Wlodek; Mendillo, Michael +3 more
The Mars Express (MEX) mission includes a multi-purpose radio instrument called the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS). When used in its ionospheric-penetrating subsurface sounder (SS) radar mode, a by-product of the MARSIS observations is the ray-path-integral of electron densities, called the total electron cont…
Utility of laser altimeter and stereoscopic terrain models: Application to Martian craters
Hynek, Brian M.; Robbins, Stuart J.
The use of numerical datasets of the same type derived from remote sensing instruments is often treated as equivalent in value and utility, within the limits of their spatial resolution. Surface topography is a good example of this. We used gridded digital terrain models (DTMs) derived from both laser altimetry and stereo pairs as well as the orig…