Publications
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Volcanic activity at Tvashtar Catena, Io
Galileo's Solid State Imager (SSI) observed Tvashtar Catena four times between November 1999 and October 2001, providing a unique look at a distinctive high latitude volcanic complex on Io. The first observation (orbit I25, November 1999) resolved, for the first time, an active extraterrestrial fissure eruption; the brightness temperature was at least 1300 K. The second observation (orbit I27, Feb
Authors
Moses P. Milazzo, Laszlo P. Keszthelyi, Jani Radebaugh, Ashley G. Davies, Elizabeth P. Turtle, Paul E. Geissler, Kenneth P. Klaasen, Julie A. Rathbun, Alfred S. McEwen
The Zamama-Thor region of Io: Insights from a synthesis of mapping, topography, and Galileo spacecraft data
We have studied data from the Galileo spacecraft's three remote sensing instruments (Solid-State Imager (SSI), Near-Infrared Mapping Spectrometer (NIMS), and Photopolarimeter-Radiometer (PPR)) covering the Zamama–Thor region of Io's antijovian hemisphere, and produced a geomorphological map of this region. This is the third of three regional maps we are producing from the Galileo spacecraft data.
Authors
David A. Williams, Laszlo P. Keszthelyi, Paul M. Schenk, Moses P. Milazzo, Rosaly M.C. Lopes, Julie A. Rathbun, Ronald Greeley
Rain, winds and haze during the Huygens probe's descent to Titan's surface
The irreversible conversion of methane into higher hydrocarbons in Titan's stratosphere implies a surface or subsurface methane reservoir. Recent measurements from the cameras aboard the Cassini orbiter fail to see a global reservoir, but the methane and smog in Titan's atmosphere impedes the search for hydrocarbons on the surface. Here we report spectra and high-resolution images obtained by the
Authors
M.G. Tomasko, B. Archinal, T. Becker, B. Bezard, M. Bushroe, M. Combes, D. Cook, A. Coustenis, C. De Bergh, L.E. Dafoe, L. Doose, S. Doute, A. Eibl, S. Engel, F. Gliem, B. Grieger, K. Holso, E. Howington-Kraus, E. Karkoschka, H.U. Keller, Randolph L. Kirk, R. Kramm, M. Kuppers, P. Lanagan, E. Lellouch, M. Lemmon, J. Lunine, E. McFarlane, J. Moores, G.M. Prout, B. Rizk, M. Rosiek, P. Rueffer, S.E. Schroder, B. Schmitt, C. See, P. Smith, Laurence A. Soderblom, N. Thomas, R. West
THEMIS VIS and IR observations of a high-altitude Martian dust devil
The Mars Odyssey Thermal Emission Imaging System (THEMIS) imaged a Martian dust devil in both visible and thermal-infrared wavelengths on January 30, 2004. We believe this is the first documented infrared observation of an extraterrestrial dust devil, and the highest to be directly observed at more than 16 kilometers above the equatorial geoid of Mars. This dust devil measured over 700 meters in h
Authors
Glen Cushing, Timothy N. Titus, Phillip R. Christensen
Thermal infrared and visual observations of a water ice lag in the Mars southern summer
We present thermal infrared and visual evidence for the existence of water ice lags in the early southern summer. The observed H2O‐ice lags lay in and near a chasma and appears to survive between 6–8 sols past the sublimation of the CO2. Possible sources of the H2O that compose the lag are (1) atmospheric H2O that is incorporated into the seasonal cap during condensation, (2) cold trapping of atmo
Authors
Timothy N. Titus
Evidence for subsurface water ice in Korolev crater, Mars
Following the work of Kieffer and Titus (2001, Icarus 154, 162–180), we present results of thermal IR observations of Korolev crater, located at ∼73° latitude in the martian northern polar region. Similar to techniques employed by Titus et al. (2003, Science 299, 1048–1050), we use infrared images from the Thermal Emission Imaging System (THEMIS) aboard Mars Odyssey to identify several regions wit
Authors
John C. Armstrong, Timothy N. Titus, Hugh H. Kieffer
Aeolian processes at the Mars Exploration Rover Meridiani Planum landing site
The martian surface is a natural laboratory for testing our understanding of the physics of aeolian (wind-related) processes in an environment different from that of Earth. Martian surface markings and atmospheric opacity are time-variable, indicating that fine particles at the surface are mobilized regularly by wind. Regolith (unconsolidated surface material) at the Mars Exploration Rover Opportu
Authors
R. Sullivan, D. Banfield, J.F. Bell, W. Calvin, D. Fike, M. Golombek, R. Greeley, J. Grotzinger, Kenneth E. Herkenhoff, D. Jerolmack, M. Malin, D. Ming, Laurence A. Soderblom, S. W. Squyres, S. Thompson, W.A. Watters, C.M. Weitz, A. Yen
Provenance and diagenesis of the evaporite-bearing Burns formation, Meridiani Planum, Mars
Impure reworked evaporitic sandstones, preserved on Meridiani Planum, Mars, are mixtures of roughly equal amounts of altered siliciclastic debris, of basaltic provenance (40 ± 10% by mass), and chemical constituents, dominated by evaporitic minerals (jarosite, Mg-, Ca-sulfates ± chlorides ± Fe-, Na-sulfates), hematite and possibly secondary silica (60 ± 10%). These chemical constituents and their
Authors
S. M. McLennan, J.F. Bell, W. M. Calvin, P. R. Christensen, B. C. Clark, P.A. de Souza, J. Farmer, W. H. Farrand, D.A. Fike, Ralf Gellert, A. Ghosh, T.D. Glotch, J.P. Grotzinger, B. Hahn, Kenneth E. Herkenhoff, J.A. Hurowitz, J. R. Johnson, S.S. Johnson, B. Jolliff, G. Klingelhofer, A.H. Knoll, Z. Learner, M. C. Malin, H.Y. McSween, J. Pocock, S. W. Ruff, Laurence A. Soderblom, S. W. Squyres, N.J. Tosca, W.A. Watters, M.B. Wyatt, A. Yen
Mars exploration rover geologic traverse by the spirit rover in the plains of Gusev crater, Mars
The Spirit rover completed a 2.5 km traverse across gently sloping plains on the floor of Gusev crater from its location on the outer rim of Bonneville crater to the lower slopes of the Columbia Hills, Mars. Using the Athena suite of instruments in a transect approach, a systematic series of overlapping panoramic mosaics, remote sensing observations, surface analyses, and trenching operations docu
Authors
L.S. Crumpler, S. W. Squyres, R. E. Arvidson, J.F. Bell, D. Blaney, N.A. Cabrol, P. R. Christensen, D.J. DesMarais, J.D. Farmer, R. Fergason, M.P. Golombek, F.D. Grant, J. A. Grant, R. Greeley, B. Hahn, Kenneth E. Herkenhoff, J.A. Hurowitz, A.T. Knudson, G. A. Landis, R. Li, J. Maki, H.Y. McSween, D. W. Ming, J.E. Moersch, M.C. Payne, J.W. Rice, L. Richter, S. W. Ruff, M. Sims, S.D. Thompson, N. Tosca, A. Wang, P. Whelley, S.P. Wright, M.B. Wyatt
Water alteration of rocks and soils on Mars at the Spirit rover site in Gusev crater
Gusev crater was selected as the landing site for the Spirit rover because of the possibility that it once held a lake. Thus one of the rover's tasks was to search for evidence of lake sediments. However, the plains at the landing site were found to be covered by a regolith composed of olivine-rich basaltic rock and wind-blown 'global' dust. The analyses of three rock interiors exposed by the rock
Authors
L.A. Haskin, A. Wang, B.L. Jolliff, H.Y. McSween, B. C. Clark, D.J. Des Marais, S. M. McLennan, N.J. Tosca, J.A. Hurowitz, J.D. Farmer, A. Yen, S. W. Squyres, R. E. Arvidson, G. Klingelhofer, C. Schroder, P.A. De Souza, D. W. Ming, Ralf Gellert, J. Zipfel, J. Brückner, J.F. Bell, Kenneth E. Herkenhoff, P. R. Christensen, S. Ruff, D. Blaney, S. Gorevan, N.A. Cabrol, L. Crumpler, J. Grant, L. Soderblom
Evidence from Opportunity’s Microscopic Imager for water on Meridiani Planum
The Microscopic Imager on the Opportunity rover analyzed textures of soils and rocks at Meridiani Planum at a scale of 31 micrometers per pixel. The uppermost millimeter of some soils is weakly cemented, whereas other soils show little evidence of cohesion. Rock outcrops are laminated on a millimeter scale; image mosaics of cross-stratification suggest that some sediments were deposited by flowing
Authors
Kenneth E. Herkenhoff, S. W. Squyres, R. Arvidson, D.S. Bass, J. F. III Bell, P. Bertelsen, B. L. Ehlmann, W. Farrand, Lisa R. Gaddis, R. Greeley, J. Grotzinger, A. G. Hayes, S.F. Hviid, J. R. Johnson, B. Jolliff, K.M. Kinch, A. H. Knoll, M.B. Madsen, J.N. Maki, S. M. McLennan, H.Y. McSween, D. W. Ming, J. W. Rice, L. Richter, M. Sims, P. H. Smith, Laurence A. Soderblom, Nicole Spanovich, R. Sullivan, S. Thompson, T. Wdowiak, C. Weitz, P. Whelley
Icelandic analogs to Martian flood lavas
We report on new field observations from Icelandic lava flows that have the same surface morphology as many Martian flood lava flows. The Martian flood lavas are characterized by a platy‐ridged surface morphology whose formation is not well understood. The examples on Mars include some of the most pristine lava on the planet and flows >1500 km long. The surfaces of the flows are characterized by (
Authors
Laszlo P. Keszthelyi, Thorvaldur Thordarson, Alfred McEwen, Henning Haack, Marie-Noelle Guilbaud, Stephen Self, Matti J. Rossi