Results from the Mars Pathfinder Camera

Smith, Peter H.; Bell, J. F.; Bridges, N. T.; Britt, D. T.; Gaddis, L. R.; Greeley, R.; Keller, H. U.; Herkenhoff, K. E.; Jaumann, R.; Johnson, J. R.; Kirk, Randolph L.; Lemmon, M. T.; Maki, J. N.; Malin, M. C.; Murchie, S. L.; Oberst, J.; Parker, T. J.; Reid, Robert J.; Sablotny, R. M.; Soderblom, Laurence A.; Stoker, C.; Sullivan, Robert; Thomas, N.; Tomasko, M. G.; Ward, Wes; Wegryn, E.

doi:10.1126/science.278.5344.1758

Cited by 238 publications

(170 citation statements)

References 32 publications

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“…Satellite and telescopic observations of variations in the integrated H 2 O column abundance (Conrath et al 1973;Jakosky and Farmer 1982;Sprague et al 1996;Smith 2004;Fedorova et al 2006;Fouchet et al 2007;Melchiorri et al 2006), in combination with numerical modeling, have been used to determine the relative importance of the various processes controlling the seasonal H 2 O cycle (Flasar and Goody 1976;Jakosky and Farmer 1982;Haberle and Jakosky 1990;Richardson and Wilson 2002;Böttger et al 2005). The seasonal H 2 O cycle is important for the Martian climate because it leads to the formation and affects the stability of water ice deposits on the surface and of water ice clouds in the atmosphere (Jakosky and Haberle 1992;Richardson and Wilson 2002;Smith et al 1997;Haberle et al 1999;Montmessin et al 2004;Madeleine et al 2012).…”

Section: Figmentioning

confidence: 99%

The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

et al. 2017

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We analyze the complete set of in-situ meteorological data obtained from the Viking landers in the 1970s to today's Curiosity rover to review our understanding of the modern near-surface climate of Mars, with focus on the dust, CO 2 and H 2 O cycles and their impact on the radiative and thermodynamic conditions near the surface. In particular, we provide values of the highest confidence possible for atmospheric opacity, atmospheric pressure, near-surface air temperature, ground temperature, near-surface wind speed and direction, and near-surface air relative humidity and water vapor content. Then, we study the diurnal, seasonal and interannual variability of these quantities over a span of more thanThe original version of this article was revised because due to an unfortunate turn of events a wrong value was published in Table 1. The resolution of the PHX pressure sensor was published as "0.1 mbar" whereas this value has now been corrected to "0.1 Pa" which is the correct value and should be regarded as the final version by the reader. B G.M. Martínez

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Section: Figmentioning

confidence: 99%

The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

et al. 2017

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“…Southwest of the lander, facing the prevailing northeast wind direction [Smith et al, 1997a], rock surfaces are generally similar spectrally. Compared to drift they exhibit a similar low blue reflectance but a lower reflectance at longer wavelengths, a lower red/blue ratio, and a weaker kink.…”

Section: Spatial Variations In Rock Spectral Propertiesmentioning

confidence: 96%

“…Although a significant amount of ejecta could have been deposited at the Pathfinder site from the large crater to the south, estimates based on the crater's size and distance from the site suggest that most of its ejecta would be significantly smaller (< 20 cm diameter) than any of the rocks analyzed by APXS [Smith et al, 1997a]. The ejecta model ofMcGetchin et al [1973] predicts that the thickness of a uniform ejecta deposit from this crater should be 0.3 m, but new crater morphology data from Mars Global Surveyor suggest that ejecta blanket thickness based on this paradigm is overestimated [Garvin and Frawley, 1998].…”

Section: Rock Norm and Classificationmentioning

confidence: 99%

Chemical, multispectral, and textural constraints on the composition and origin of rocks at the Mars Pathfinder landing site

McSween¹,

Murchie²,

Crisp³

et al. 1999

J. Geophys. Res.

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Abstract. Rocks at the Mars Pathfinder site are probably locally derived. Textures on rock surfaces may indicate volcanic, sedimentary, or impact-generated rocks, but aeolian abration and dust coatings prevent unambiguous interpretation. Multispectral imaging has resolved four spectral classes of rocks: gray and red, which occur on different surfaces of the same rocks; pink, which is probably soil crusts; and maroon, which occurs as large boulders, mostly in the far field. Rocks are assigned to two spectral trends based on the position of peak reflectance: the primary spectral trend contains gray, red, and pink rocks; maroon rocks constitute the secondary spectral trend. The spatial pattern of spectral variations observed is oriented along the prevailing wind direction. The primary spectral trend arises from thin ferric coatings of aeolian dust on darker rocks. The secondary spectral trend is apparently due to coating by a different mineral, probably maghemite or ferrihydrite. A chronology based on rock spectra suggests that rounded maroon boulders constitute the oldest petrologic unit (a flood deposit), succeeded by smaller cobbles possibly deposited by impact, and followed by aeolian erosion and deposition. Nearly linear chemical trends in alpha proton X-ray spectrometer rock compositions are interpreted as mixing lines between rock and adhering dust, a conclusion supported by a correlation between sulfur abundance and red/blue spectral ratio. Extrapolations of regression lines to zero sulfur give the composition of a presumed igneous rock. The chemistry and normative mineralogy of the sulfurfree rock resemble common terrestrial volcanic rocks, and its classification corresponds to andesite. Igneous rocks of this composition my occur with clastic sedimentary rocks or impact melts and breccias. However, the spectral mottling expected on conglomerates or breccias is not observed in any APXS-analyzed rocks. Interpretation of the rocks as andesites is complicated by absence of a "1 gm" pyroxene absorption band. Plausible explanations include impact glass, band masking by magnetite, or presence of calcium-and iron-rich pyroxenes and olivine which push the absorption band minimum past the imager's spectral range. The inferred andesitic composition is most sinfilar to terrestrial anorogenic icelandites, formed by fractionation of tholeiitic basaltic magmas. Early melting of a relatively primitive Martian mantle could produce an appropriate parent magma, supporting the ancient age of Patlff•nder rocks inferred from their incorporation in Hesperian flood deposits. Although rocks of andesitic composition at the Patlff•nder site may represent samples of ancient Martian crust, inferences drawn about a necessary role for water or plate tectonics in their petrogenesis are probably unwarranted.

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“…Recent data from the Mars Global Surveyor Thermal Emission Spectrometer show a region interpreted to be crystalline hematite (•-Fe203) approximately 300 km in diameter near the equator at -•5øW [Christensen et al, 1999]. In situ data from the Mars Pathfinder camera indicate that iron minerals may also be responsible for a 930 nm absorption in some soils [Smith et al, 1997]. A ferric component was also inferred from the Viking magnetic properties experiments which indicated the presence of 1% to 7% of a highly magnetic mineral phase, likely maghemite (¾-Fe203), in the Martian soil [Hargraves et al, 1977].…”

Section: Ferric Minerals On Marsmentioning

confidence: 99%

Stability of hydroxylated minerals on Mars: A study on the effects of exposure to ultraviolet radiation

Yen¹,

Murray²,

Rossman³

et al. 1999

J. Geophys. Res.

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Abstract. The density and composition of the Martian atmosphere allow solar ultraviolet photons with wavelengths as short as 190 nm to reach the surface. We investigate the hypothesis that this UV radiation is capable of inducing the release of water from iron oxyhydroxide minerals resulting in the formation of oxide phases. These experiments, which utilize a quadrupole mass spectrometer to monitor the water vapor pressure above mineral samples during cyclic exposure to ultraviolet radiation, offer 5 to 6 orders of magnitude greater sensitivity than previous attempts to establish and quantify this process. We find no evidence that UV photons are capable of liberating OH from the crystal lattice of minerals, and we set a minimum ultraviolet radiationinduced dehydroxylation time of 108 years for removal of this structural OH from mineral particles at the Martian surface. The overturning timescales for surface fines are likely to be shorter than this lower limit for exposure time. Thus we conclude that UV-stimulated dehydroxylation is not a significant process at the Martian surface and that iron oxyhydroxides, if formed during an earlier water-rich environment, should still be found on Mars today. The lack of clear evidence for iron oxyhydroxides at the Martian surface further suggests that Mars' surface was never warm and wet for a long enough period of time for Earth-like weathering to have occurred.

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Results from the Mars Pathfinder Camera

Abstract: Results from the Mars Pathfinder Camera Haze particles are about 1 micrometer in radius and the water vapor column abundance is about 10 precipitable micrometers.

Cited by 238 publications

References 32 publications

The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity

Chemical, multispectral, and textural constraints on the composition and origin of rocks at the Mars Pathfinder landing site

Stability of hydroxylated minerals on Mars: A study on the effects of exposure to ultraviolet radiation

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