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
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
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
Soil grain analyses at Meridiani Planum, Mars Soil grain analyses at Meridiani Planum, Mars
Grain‐size analyses of the soils at Meridiani Planum have been used to identify rock sources for the grains and provide information about depositional processes under past and current conditions. Basaltic sand, dust, millimeter‐size hematite‐rich spherules interpreted as concretions, spherule fragments, coated partially buried spherules, basalt fragments, sedimentary outcrop fragments...
Authors
C.M. Weitz, R. C. Anderson, J.F. Bell, W. H. Farrand, Kenneth E. Herkenhoff, J. R. Johnson, B.L. Jolliff, R.V. Morris, S. W. Squyres, R.J. Sullivan
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
Titan Radar Mapper observations from Cassini's T3 fly-by Titan Radar Mapper observations from Cassini's T3 fly-by
Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be...
Authors
C. Elachi, S. Wall, M. Janssen, E. Stofan, R. Lopes, Randolph L. Kirk, R. Lorenz, J. Lunine, F. Paganelli, Laurence A. Soderblom, C. Wood, L. Wye, H. Zebker, Y. Anderson, S. Ostro, M. Allison, R. Boehmer, P. Callahan, P. Encrenaz, E. Flamini, 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, 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
Alkaline volcanic rocks from the Columbia Hills, Gusev crater, Mars Alkaline volcanic rocks from the Columbia Hills, Gusev crater, Mars
Irvine, Backstay, and Wishstone are the type specimens for three classes of fine-grained or fragmental, relatively unaltered rocks with distinctive thermal emission spectra, found as float on the flanks of the Columbia Hills. Chemical analyses indicate that these rocks are mildly alkaline basalt, trachybasalt, and tephrite, respectively. Their mineralogy consists of Na- and K-rich...
Authors
H.Y. McSween, S. W. Ruff, R.V. Morris, J.F. Bell, Kenneth E. Herkenhoff, Ralf Gellert, K.R. Stockstill, L.L. Tornabene, S. W. Squyres, J.A. Crisp, P. R. Christensen, T.J. McCoy, D. W. Mittlefehldt, M. Schmidt
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
Cartography for lunar exploration: 2006 status and planned missions Cartography for lunar exploration: 2006 status and planned missions
The initial spacecraft exploration of the Moon in the 1960s–70s yielded extensive data, primarily in the form of film and television images, that were used to produce a large number of hardcopy maps by conventional techniques. A second era of exploration, beginning in the early 1990s, has produced digital data including global multispectral imagery and altimetry, from which a new...
Authors
Randolph L. Kirk, Brent A. Archinal, Lisa R. Gaddis, Mark R. Rosiek
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
Two years at Meridiani Planum: Results from the Opportunity Rover Two years at Meridiani Planum: Results from the Opportunity Rover
The Mars Exploration Rover Opportunity has spent more than 2 years exploring Meridiani Planum, traveling ∼8 kilometers and detecting features that reveal ancient environmental conditions. These include well-developed festoon (trough) cross-lamination formed in flowing liquid water, strata with smaller and more abundant hematite-rich concretions than those seen previously, possible relict...
Authors
S. W. Squyres, A.H. Knoll, R. E. Arvidson, B. C. Clark, J.P. Grotzinger, B.L. Jolliff, S. M. McLennan, N. Tosca, J.F. Bell, W. M. Calvin, W. H. Farrand, T.D. Glotch, M.P. Golombek, Kenneth E. Herkenhoff, J. R. Johnson, G. Klingelhofer, H.Y. McSween, A. S. Yen