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Part VI - Summary, Upcoming Missions, and New Measurement Needs
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- By J. F. Bell III, Associate Professor, Department of Astronomy, Cornell University
- Edited by Jim Bell, Cornell University, New York
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- Book:
- The Martian Surface
- Published online:
- 10 December 2009
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- 05 June 2008, pp 625-626
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27 - The future of Mars exploration
- from Part VI - Summary, Upcoming Missions, and New Measurement Needs
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- By J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA
- Edited by Jim Bell, Cornell University, New York
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- Book:
- The Martian Surface
- Published online:
- 10 December 2009
- Print publication:
- 05 June 2008, pp 627-630
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Summary
INTRODUCTION
The information, interpretations, and speculations in this book represent a snapshot in time. Planetary scientists are in the midst of what is – despite the cliché – truly a golden age of Mars exploration. Most of us hardly have time to catch our breath before some new, exciting image or spectrum or model result pops up on our computer screens – or, many times, in our newspapers and TV screens.
Trying to summarize the state of a rapidly moving scientific field such as the current exploration of Mars is challenging at best, futile at worst. However, the authors of the preceding chapters of this book have risen to the challenge admirably and have provided outstanding, timely summaries of the specific aspects of Mars science that are the main focus of this book: the composition, mineralogy, and physical properties of the surface. If this book had been written five years ago, it would have presented an entirely different perspective. It is humbling to also realize that if we had all waited to write this book five years from now, the data, interpretations, and speculations would also almost certainly again be significantly different from what is summarized here. Mars is a moving target, but at some point one has to let the arrow fly.
ENDINGS
If there ever were an optimal time to try to stop for a moment and grasp the implications of the stunning observations and discoveries of the past 15 years in Mars science, now might arguably be that time.
8 - Visible to near-IR multispectral orbital observations of Mars
- from Part III - Mineralogy and Remote Sensing of Rocks, Soil, Dust, and Ices
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- By J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA, T. D. Glotch, Department of Geosciences, SUNY at Stony Brook Stony Brook, NY 11794, USA, V. E. Hamilton, Hawaii Institute of Geophysics & Planetology, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822, USA, T. McConnochie, NASA Goddard Space Flight Center Mailstop 693.0 Greenbelt, MD 20771, USA, T. McCord, Space Science Institute 4750 Walnut Street, Suite 205 Boulder, Colorado 80301, USA, A. McEwen, Lunar & Planetary Laboratory University of Arizona, 1541 E. University Blvd. Tuscon, AZ 85721-0063, USA, P. R. Christensen, Planetary Exploration Laboratory Arizona State University Moeur Building 110D Tempe, AZ 85287, USA, R. E. Arvidson, Earth & Planetary Science, Washington University St Louis, MO 63130, USA
- Edited by Jim Bell, Cornell University, New York
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- Book:
- The Martian Surface
- Published online:
- 10 December 2009
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- 05 June 2008, pp 169-192
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Summary
ABSTRACT
This chapter reviews observations and interpretations since the 1990s from orbital telescopic and spacecraft observations of Mars from the extended visible to short-wave near-IR (VNIR) wavelength range. Imaging and spectroscopic measurements from the Hubble Space Telescope (HST), Mars Global Surveyor Mars Orbiter Camera Wide Angle (MGS MOC/WA) instrument, Mars Odyssey Thermal Emission Imaging System Visible Subsystem (THEMIS-VIS), and Mars Express High Resolution Stereo Camera (MEx HRSC) and Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité (OMEGA) have been acquired at spatial scales from global-scale ∼ 1 to hundreds of kilometers resolution to regional-scale ∼ 20–100 m resolution. Most high-albedo regions are homogeneous in color and thus, likely, composition, a supposition consistent with the long-held idea of the presence of a globally homogeneous aeolian dust unit covering much of the surface. Despite the presence and ubiquity of dust, these measurements still reveal the presence of significant VNIR spectral variability at a variety of spatial scales. For example, color variations and possibly mineralogic variations have been detected among small-scale (tens of meters) exposures of light-toned outcrop and layered materials in Meridiani Planum, Valles Marineris, and other areas. Within low-albedo regions, much of the observed color variability appears simply related to different amounts of covering or coating by nanophase ferric oxide-bearing dust and/or ferrous silicate-bearing sand. Some VNIR color units, however, in regions spanning the full range of observed surface albedos, correlate with geologic, topographic, or thermal inertia boundaries, suggesting that either composition/mineralogy or variations in physical properties (e.g., grain size, roughness, packing density) influence the observed color.
13 - Mars Exploration Rover Pancam multispectral imaging of rocks, soils, and dust at Gusev crater and Meridiani Planum
- from Part III - Mineralogy and Remote Sensing of Rocks, Soil, Dust, and Ices
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- By J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA, W. M. Calvin, Department of Geological Science, MS 172, University of Nevada Reno, NV 89557-0138, USA, W. H. Farrand, Space Science Institute 4750 Walnut Street, # 205 Boulder, CO 80301, USA, R. Greeley, Planetary Geology Group Arizona State University Tempe, AZ 85287-1404, USA, J. R. Johnson, US Geological Survey Astrogeology Team 2255 N. Gemini Drive Flagstaff, AZ 86001-1698, USA, B. Jolliff, Washington University, Campus Box 1169 One Bookings Drive St Louis, MO 63130, USA, R. V. Morris, NASA/JSC Code KR, Building 31, Room 120 2101 NASA Road 1 Houston, TX 77058, USA, R. J. Sullivan, CRSR Cornell University, 308 Space Sciences Building Ithaca, NY 14853, USA, S. Thompson, Arizona State University, School of Earth and Space Exploration Box 871404 Tempe, AZ 85287, USA, A. Wang, Department of Earth & Planetary Sciences, Washington University, Campus Box 1196 1 Bookings Drive St Louis, MO 63130-4862, USA, C. Weitz, Planetary Science Institute, NASA 1700 East Fort Lowell Suite 106 Tuscon, AZ 85719, USA, S. W. Squyres, Department of Astronomy, Cornell University, 428 Space Sciences Building, Ithaca, NY 14853, USA
- Edited by Jim Bell, Cornell University, New York
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- Book:
- The Martian Surface
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- 10 December 2009
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- 05 June 2008, pp 281-314
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Summary
ABSTRACT
Multispectral imaging from the Panoramic Camera (Pancam) instruments on the Mars Exploration Rovers (MERs) Spirit and Opportunity has provided important new insights about the geology and geologic history of the rover landing sites and traverse locations in Gusev crater and Meridiani Planum. Pancam observations from near-UV to near-infrared (NIR) wavelengths provide limited compositional and mineralogic constraints on the presence, abundance, and physical properties of ferric- and ferrous-iron–bearing minerals in rocks, soils, and dust at both sites. High-resolution and stereo morphologic observations have also helped to infer some aspects of the composition of these materials at both sites. Perhaps most importantly, Pancam observations were often efficiently and effectively used to discover and select the relatively small number of places where in situ measurements were performed by the rover instruments, thus supporting and enabling the much more quantitative mineralogic discoveries made using elemental chemistry and mineralogy data. This chapter summarizes the major compositionally and mineralogically relevant results at Gusev and Meridiani derived from Pancam observations. Classes of materials encountered in Gusev crater include outcrop rocks, float rocks, cobbles, clasts, soils, dust, rock grindings, rock coatings, windblown drift deposits, and exhumed whitish/yellowish sulfur- and silica-rich soils. Materials studied in Meridiani Planum include sedimentary outcrop rocks, rock rinds, fracture fills, hematite spherules, cobbles, rock fragments, meteorites, soils, and windblown drift deposits. This chapter also previews the results of a number of coordinated observations between Pancam and other rover-based and Mars-orbital instruments that were designed to provide complementary new information and constraints on the mineralogy and physical properties of Martian surface materials.
19 - Physical properties of the Martian surface from spectrophotometric observations
- from Part IV - Physical Properties of Surface Materials
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- By J. R. Johnson, US Geological Survey Astrogeology Team 2255 N. Gemini Drive Flagstaff, AZ 86001-1698, USA, J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA, P. Geissler, US Geological Survey 2255 N. Gemini Drive Flagstaff, AZ 86001, USA, W. M. Grundy, Lowell Observatory 1400 W. Mars Hill Road Flagstaff, AZ 86001, USA, E. A. Guinness, Washington University, Campus Box 1169 St Louis, MO 63130, USA, P. C. Pinet, UMR 5562/CNRS Observatoire Midi-Pyrenees 14 Avenue Edouard Belin Toulouse, 31400, France, J. Soderblom, Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd. Tucson, AZ 85721, USA
- Edited by Jim Bell, Cornell University, New York
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- Book:
- The Martian Surface
- Published online:
- 10 December 2009
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- 05 June 2008, pp 428-450
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Summary
ABSTRACT
The reflection of visible and near-infrared light from Mars can vary significantly depending on the directional scattering characteristics of surface materials. Observations acquired under a range of illumination and viewing angles can be input to radiative transfer models to constrain the albedo, surface roughness, grain size, and/or porosity of these materials. This chapter reviews multiangular measurements of Mars obtained by Earth-based telescopes (including the Hubble Space Telescope), orbiters (Mariner, Viking, Mars Express), landers (Viking, Mars Pathfinder), and rovers (Mars Exploration Rovers), and how the photometric analyses of these datasets have been used to understand the surface properties of local and regional geologic units and terrain types. Although acquisition of data covering sufficient incidence, emission, or phase angles to fully constrain all parameters within photometric models is challenging, a common theme among these studies is the dominantly backscattering nature of the Martian surface, the magnitude of which is often related to the presence of high-albedo aeolian dust. The local and regional photometric variability observed in these data encourages further refinement of radiative transfer methods and atmospheric correction algorithms to provide additional tools with which to categorize and map distinct photometric units on Mars, particularly to provide support for ongoing and upcoming orbital and landed missions.
21 - Martian surface properties from joint analysis of orbital, Earth-based, and surface observations
- from Part IV - Physical Properties of Surface Materials
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- By M. P. Golombek, JPL MS 183-501 4800 Oak Grove Drive Pasadena, CA 91109, USA, A. F. C. Haldemann, JPL 4800 Oak Grove Drive Pasadena, CA 91109, USA, R. A. Simpson, Stanford University, David Packard #332 350 Serra Mall Stanford, CA 94305-9515, USA, R. L. Fergason, School of Earth & Space Exploration Arizona State University, PO Box 876305 Tempe, AZ 85287-6305, USA, N. E. Putzig, Laboratory for Atmospheric & Space Physics, University of Colorado, Campus Box 392 Boulder, CO 80309, USA, R. E. Arvidson, Earth & Planetary Science, Washington University, St Louis, MO 63130, USA, J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA, M. T. Mellon, Laboratory for Atmospheric & Space Physics, University of Colorado – Boulder Boulder, CO 80309-0392, USA
- Edited by Jim Bell, Cornell University, New York
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- The Martian Surface
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- 10 December 2009
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- 05 June 2008, pp 468-498
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Summary
ABSTRACT
Surface characteristics at the five sites where spacecraft have successfully landed on Mars can be related favorably to their signatures in remotely sensed data from orbit and from the Earth. Comparisons of the rock abundance, types and coverage of soils (and their physical properties), thermal inertia, albedo, and topographic slope all agree with orbital remote-sensing estimates and show that the materials at the landing sites can be used as “ground truth” for the materials that make up most of the equatorial and mid-latitude regions of Mars. The five landing sites sample two of the three dominant global thermal inertia and albedo units that cover ∼ 80% of the surface of Mars. The Viking Landers 1 and 2, Spirit, and Mars Pathfinder landing sites are representative of the moderate-to-high thermal inertia and intermediate-to-high albedo unit that is dominated by crusty, cloddy, and blocky soils (duricrust) with various abundances of rocks and bright dust. The Opportunity landing site is representative of the moderate-to-high thermal inertia and low-albedo surface unit that is relatively dust-free and composed of dark eolian sand and/or increased abundance of rocks. Interpretation of radar data confirms the presence of load bearing, relatively dense surfaces controlled by the soil type at the landing sites, regional rock populations from diffuse scattering similar to those observed directly at the sites, and root-mean-squared (RMS) slopes that compare favorably with 100 m scale topographic slopes extrapolated from altimetry profiles and meter scale slopes from high-resolution stereo images.
1 - Exploration of the Martian surface: 1992–2007
- from Part I - Introduction and historical perspective
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- By L. A. Soderblom, US Geological Survey, 2255 North Gemini Drive Flagstaff, AZ 86001, USA, J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA
- Edited by Jim Bell, Cornell University, New York
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- Book:
- The Martian Surface
- Published online:
- 10 December 2009
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- 05 June 2008, pp 3-19
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ABSTRACT
Following the demise of the 1992 Mars Observer mission, NASA and the planetary science community completely redefined the Mars exploration program. “Follow the Water” became the overarching scientific theme. The history and distribution of water is fundamental to an understanding of climate history, formation of the atmosphere, geologic evolution, and Mars' modern state. The strategy was to search for past or present, surface or subsurface, environments where liquid water, the fundamental prerequisite for life, existed or exists today. During the 1996–2007 time frame, seven richly successful orbital and landed missions have explored the Martian surface, including NASA's Mars Global Surveyor (MGS), Mars Pathfinder Lander and Sojourner Rover, Mars Odyssey Orbiter, Mars Exploration Rovers (Spirit and Opportunity), Mars Reconnaissance Orbiter, and ESA's Mars Express (MEx) orbiter. “Follow the Water” has borne fruit. Although the Martian surface is largely composed of unaltered basaltic rocks and sand, the Rovers discovered water-lain sediments, some minerals only formed in water, and aqueous alteration of chemically fragile igneous minerals. The geological records of early water-rich environment have shown hints of profuse and neutral-to-alkaline water that later evolved to sulfurous acidic conditions as aqueous activity waned. We now have a global inventory of near-surface water occurring as hydrated minerals and possibly ice and liquid in equatorial and mid latitudes and as masses of water ice making up an unknown but potentially large fraction of the polar regolith. Martian meteorites have provided new insights into the early formation of Mars' core and mantle.
2 - Historical context: the pre-MGS view of Mars' surface composition
- from Part I - Introduction and historical perspective
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- By W. M. Calvin, Department of Geological Science, MS 172, University of Nevada Reno, NV 89557-0138, USA, J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA
- Edited by Jim Bell, Cornell University, New York
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- Book:
- The Martian Surface
- Published online:
- 10 December 2009
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- 05 June 2008, pp 20-30
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Summary
ABSTRACT
This chapter summarizes the state of understanding of Mars surface composition in the decade before the arrival of Mars Global Surveyor and Mars Pathfinder (about 1987–1997), updating earlier historical reviews on this topic by Soderblom (1992) and Roush et al. (1993). Here we summarize analyses of telescopic and spacecraft spectroscopic data sets with reference to relevant terrestrial analog studies, laboratory measurements, and modeling work. The chapter is organized around a synthesis of surface mineralogy types that have been identified and searched for: unaltered mafic volcanic minerals; alteration products including oxidized iron, hydrated minerals, and phyllosilicates; the search for carbonates; early, if equivocal evidence of sulfates; and finally, polar deposits. We highlight the way that these precursor studies have influenced the design, selection, and implementation of the current generation of science investigations focused on unraveling the composition and mineralogy of the surface of Mars.
12 - Multispectral imaging from Mars Pathfinder
- from Part III - Mineralogy and Remote Sensing of Rocks, Soil, Dust, and Ices
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- By W. H. Farrand, Space Science Institute 4750 Walnut Street, # 205 Boulder, CO 80301, USA, J. F. Bell III, Cornell University, Department of Astronomy, 402 Space Sciences Building, Ithaca, NY 14853-6801, USA, J. R. Johnson, Cold Regions Research & Engineering Laboratory Alaska Office PO Box 35170 Ft. Wainwright, AK 99703, USA, J. L. Bishop, SETI Institute 515 N. Whisman Road Mountain View, CA 94034, USA, R. V. Morris, NASA/JSC Cose KR, Building 31, Room 120 2101 NASA Road 1 Houston, TX 77058, USA
- Edited by Jim Bell, Cornell University, New York
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- The Martian Surface
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- 10 December 2009
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- 05 June 2008, pp 263-280
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ABSTRACT
The Imager for Mars Pathfinder (IMP) was a mast-mounted instrument on the Mars Pathfinder (MPF) lander which landed on Mars' Ares Vallis floodplain on July 4, 1997. During the 83 sols of MPF landed operations, the IMP collected over 16 600 images. Multispectral images were collected using 12 narrowband filters at wavelengths between 400 and 1000 nm in the visible and near-infrared (VNIR) range. The IMP provided VNIR spectra of the materials surrounding the lander including rocks, bright soils, dark soils, and atmospheric observations. During the primary mission, only a single primary rock spectral class, “Gray Rock,” was recognized; since then, “Black Rock” has been identified. The Black Rock spectra have a stronger absorption at longer wavelengths than do Gray Rock spectra. A number of coated rocks have also been described, the Red and Maroon Rock classes, and perhaps indurated soils in the form of the Pink Rock class. A number of different soil types were also recognized with the primary ones being Bright Red Drift, Dark Soil, Brown Soil, and Disturbed Soil. Examination of spectral parameter plots indicated two trends which were interpreted as representing alteration products formed in at least two different environmental epochs of the Ares Vallis area. Subsequent analysis of the data and comparison with terrestrial analogs have supported the interpretation that the rock coatings provide evidence of earlier Martian environments.
HST studies of Mars
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- By J. F. Bell III, Department of Astronomy, Cornell University, 402, Space Sciences Building, Ithaca, NY 14853-6801
- Edited by Mario Livio, Space Telescope Science Institute, Baltimore, Keith Noll, Space Telescope Science Institute, Baltimore, Massimo Stiavelli, Space Telescope Science Institute, Baltimore
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- A Decade of Hubble Space Telescope Science
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- 13 August 2009
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- 26 June 2003, pp 1-24
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Summary
HST observed Mars during all 5 oppositions between 1990 and 1999, providing unique new observations of the planet's atmosphere and surface during seasons which are typically poorly-observed telescopically and in wavelength regions or at spatial scales that are not at all observed by spacecraft. HST observations also filled a crucial gap in synoptic observations of Mars prior to 1998, during a time when no spacecraft were observing the planet. HST data have provided important new insights and understanding of the Martian atmosphere, surface, and satellites, and they continue to fulfill important spacecraft mission support functions, including atmospheric aerosol characterization, dust storm monitoring, and instrument cross-calibration.
Introduction
Mars has been the subject of intense telescopic observations for centuries (see, for example, reviews by Martin et al. 1992 and Sheehan 1988). Interest in the red planet stems partly from its prominent appearance in the night sky as a bright extended object roughly every 26 months, and also from historic telescopic observations and more recent spacecraft encounters that have revealed many similarities between Mars and the Earth in terms of surface and atmospheric characteristics and climatic histories. While cold and arid today and probably inhospitable to most forms of life, evidence exists indicating that Mars once may have had a much more clement climate, during a postulated “warm and wet” epoch early in solar system history (e.g. Pollack et al. 1987; Carr, 1998).