Publications
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The sand seas of titan: Cassini RADAR observations of longitudinal dunes The sand seas of titan: Cassini RADAR observations of longitudinal dunes
The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show ∼100-meter ridges consistent with duneforms and reveal flow interactions with...
Authors
R. D. Lorenz, S. Wall, J. Radebaugh, G. Boubin, E. Reffet, M. Janssen, E. Stofan, R. Lopes, Randolph L. Kirk, C. Elachi, J. Lunine, Ken Mitchell, F. Paganelli, Laurence A. Soderblom, C. Wood, L. Wye, H. Zebker, Y. Anderson, S. Ostro, M. Allison, R. Boehmer, P. Callahan, P. Encrenaz, G.G. Ori, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, W. Johnson, K. Kelleher, D. Muhleman, G. Picardi, F. Posa, L. Roth, R. Seu, S. Shaffer, B. Stiles, S. Vetrella, E. Flamini, R. West
Evidence of phyllosilicates in Wooly Patch, an altered rock encountered at West Spur, Columbia Hills, by the Spirit rover in Gusev crater, Mars Evidence of phyllosilicates in Wooly Patch, an altered rock encountered at West Spur, Columbia Hills, by the Spirit rover in Gusev crater, Mars
On its traverse to Columbia Hills, the Mars Exploration Rover Spirit investigated an outcrop designated “Wooly Patch” that exhibited morphological, mineralogical, and geochemical characteristics at the extreme ends of ranges observed among rocks studied at West Spur, a westward projecting salient near the foot of the Columbia Hills, Gusev crater. The major‐element composition and Fe...
Authors
A. Wang, R.L. Korotev, B.L. Jolliff, L.A. Haskin, L. Crumpler, W. H. Farrand, Kenneth E. Herkenhoff, Jr. de Souza, A.G. Kusack, J.A. Hurowitz, N.J. Tosca
Characterization and petrologic interpretation of olivine-rich basalts at Gusev Crater, Mars Characterization and petrologic interpretation of olivine-rich basalts at Gusev Crater, Mars
Rocks on the floor of Gusev crater are basalts of uniform composition and mineralogy. Olivine, the only mineral to have been identified or inferred from data by all instruments on the Spirit rover, is especially abundant in these rocks. These picritic basalts are similar in many respects to certain Martian meteorites (olivine-phyric shergottites). The olivine megacrysts in both have...
Authors
H.Y. McSween, M.B. Wyatt, Ralf Gellert, J.F. Bell, R.V. Morris, Kenneth E. Herkenhoff, L.S. Crumpler, K.A. Milam, K.R. Stockstill, L.L. Tornabene, R. E. Arvidson, P. Bartlett, D. Blaney, N.A. Cabrol, P. R. Christensen, B. C. Clark, J.A. Crisp, D.J. Des Marais, T. Economou, J.D. Farmer, W. Farrand, A. Ghosh, M. Golombek, S. Gorevan, R. Greeley, V.E. Hamilton, J. R. Johnson, B.L. Joliff, G. Klingelhofer, A.T. Knudson, S. McLennan, D. Ming, J.E. Moersch, R. Rieder, S. W. Ruff, C. Schroder, P.A. de Souza, S. W. Squyres, H. Wanke, A. Wang, A. Yen, J. Zipfel
Spectrophotometric properties of materials observed by Pancam on the Mars Exploration Rovers: 2. Opportunity Spectrophotometric properties of materials observed by Pancam on the Mars Exploration Rovers: 2. Opportunity
The Panoramic Camera (Pancam) on the Mars Exploration Rover Opportunity acquired visible/near‐infrared multispectral observations of soils and rocks under varying viewing and illumination geometries that were modeled using radiative transfer theory to improve interpretations of the microphysical and surface scattering nature of materials in Meridiani Planum. Nearly 25,000 individual...
Authors
J. R. Johnson, W.M. Grundy, M.T. Lemmon, J.F. Bell, M. J. Johnson, R. Deen, R. E. Arvidson, W. H. Farrand, E. Guinness, A. G. Hayes, Kenneth E. Herkenhoff, F. Seelos, J. Soderblom, S. Squyres
Shocked plagioclase signatures in Thermal Emission Spectrometer data of Mars Shocked plagioclase signatures in Thermal Emission Spectrometer data of Mars
The extensive impact cratering record on Mars combined with evidence from SNC meteorites suggests that a significant fraction of the surface is composed of materials subjected to variable shock pressures. Pressure-induced structural changes in minerals during high-pressure shock events alter their thermal infrared spectral emission features, particularly for feldspars, in a predictable...
Authors
Jeffrey R. Johnson, Matthew I. Staid, Timothy N. Titus, Kris J. Becker
USGS Magellan stereomapping of Venus USGS Magellan stereomapping of Venus
This paper describes our methods for generating high resolution Digital Terrain Models (DTMs) of Venus using Magellan synthetic aperture radar (SAR) stereoimages, and the sensor model we developed for Magellan stereomapping on our digital photogrammetric workstation running SOCET SET (® BAE SYSTEMS). In addition to demonstrating the validity of our sensor model and procedures we use for...
Authors
Elpitha Howington-Kraus, Randolph L. Kirk, Donna M. Galuszka, Bonnie L. Redding
Derivation of planetary topography using multi-image shape-from-shading Derivation of planetary topography using multi-image shape-from-shading
In many cases, the derivation of high-resolution digital terrain models (DTMs) from planetary surfaces using conventional digital image matching is a problem. The matching methods need at least one stereo pair of images with sufficient texture. However, many space missions provide only a few stereo images and planetary surfaces often possess insufficient texture. This paper describes a...
Authors
Volker Lohse, Christian Heipke, Randolph L. Kirk
Nature and origin of the hematite-bearing plains of Terra Meridiani based on analyses of orbital and Mars Exploration rover data sets Nature and origin of the hematite-bearing plains of Terra Meridiani based on analyses of orbital and Mars Exploration rover data sets
The ∼5 km of traverses and observations completed by the Opportunity rover from Endurance crater to the Fruitbasket outcrop show that the Meridiani plains consist of sulfate‐rich sedimentary rocks that are largely covered by poorly‐sorted basaltic aeolian sands and a lag of granule‐sized hematitic concretions. Orbital reflectance spectra obtained by Mars Express OMEGA over this region...
Authors
R. E. Arvidson, F. Poulet, R.V. Morris, J.-P. Bibring, J.F. Bell, S. W. Squyres, P. R. Christensen, G. Bellucci, B. Gondet, B.L. Ehlmann, W. H. Farrand, R.L. Fergason, M. Golombeck, J.L. Griffes, J. Grotzinger, E.A. Guinness, Kenneth E. Herkenhoff, J. R. Johnson, G. Klingelhofer, Y. Langevin, D. Ming, K. Seelos, R.J. Sullivan, J.G. Ward, S.M. Wiseman, M.J. Wolff
Aqueous processes at Gusev crater inferred from physical properties of rocks and soils along the Spirit traverse Aqueous processes at Gusev crater inferred from physical properties of rocks and soils along the Spirit traverse
Gusev crater was selected as the landing site for Spirit on the basis of morphological evidence of long-lasting water activity, including possibly fluvial and lacustrine episodes. From the Columbia Memorial Station to the Columbia Hills, Spirit's traverse provides a journey back in time, from relatively recent volcanic plains showing little evidence for aqueous processes up to the older...
Authors
N.A. Cabrol, J.D. Farmer, E.A. Grin, L. Ritcher, L. Soderblom, R. Li, Kenneth E. Herkenhoff, G. A. Landis, R. E. Arvidson
Mapping of Titan: Results from the first Titan radar passes Mapping of Titan: Results from the first Titan radar passes
The first two swaths collected by Cassini's Titan Radar Mapper were obtained in October of 2004 (Ta) and February of 2005 (T3). The Ta swath provides evidence for cryovolcanic processes, the possible occurrence of fluvial channels and lakes, and some tectonic activity. The T3 swath has extensive areas of dunes and two large impact craters. We interpret the brightness variations in much...
Authors
E. R. Stofan, J. I. Lunine, R. Lopes, F. Paganelli, R. D. Lorenz, C. A. Wood, Randolph L. Kirk, S. Wall, C. Elachi, Laurence A. Soderblom, S. Ostro, M. Janssen, J. Radebaugh, L. Wye, H. Zebker, Y. Anderson, M. Allison, R. Boehmer, P. Callahan, P. Encrenaz, E. Flamini, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, W.T.K. Johnson, K. Kelleher, D. Muhleman, G. Picardi, F. Posa, L. Roth, R. Seu, S. Shaffer, B. Stiles, S. Vetrella, R. West
Bedrock formation at Meridiani Planum Bedrock formation at Meridiani Planum
The Mars Exploration Rover Opportunity discovered sulphate-rich sedimentary rocks at Meridiani Planum on Mars, which are interpreted by McCollom and Hynek as altered volcanic rocks. However, their conclusions are derived from an incorrect representation of our depositional model, which is upheld by more recent Rover data. We contend that all the available data still support an aeolian...
Authors
S. W. Squyres, O. Aharonson, R. E. Arvidson, J.F. Bell, P. R. Christensen, B. C. Clark, J.A. Crisp, W. Farrand, T. Glotch, M.P. Golombek, J. Grant, J. Grotzinger, Kenneth E. Herkenhoff, J. R. Johnson, B.L. Jolliff, A.H. Knoll, S. M. McLennan, H.Y. McSween, Johnnie N. Moore, J. W. Rice, N. Tosca
Petrogenesis of the Apollo 14 high-alumina basalts: Implications from ion microprobe analyses Petrogenesis of the Apollo 14 high-alumina basalts: Implications from ion microprobe analyses
In this study, ion microprobe analyses of individual minerals are used to investigate the petrogenesis of the Apollo 14 high-Al basalts. We use trace element concentrations from individual minerals in the Apollo 14 high-Al basalts to evaluate both endogenic and exogenic models. The data show that if the Apollo 14 high-Al basalts were produced by melting within the lunar mantle, these...
Authors
Justin Hagerty, Charles K. Shearer, James J. Papike