Inorganic Analyses of Martian Surface Samples at the Viking Landing Sites

Clark, B. C.; Baird, A. K.; Rose, Harry J.; Toulmin, Priestley; Keil, K.; Castro, A. J.; Kelliher, Warren C.; Rowe, Catherine D.; Evans, Peter H.

doi:10.1126/science.194.4271.1283

Cited by 195 publications

(79 citation statements)

References 16 publications

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“…18) indicates that 1% and 10% Fe2O3 causes oxidation of Ϸ10% and 40%, respectively, of the organic matter; for Fe2(SO4)3, the values are 35% and 45%. Sulfur represents only 3.1 Ϯ 0.5% of the soil at both Viking landing sites (19). Therefore, iron sulfate must be a minor component, compared with oxide.…”

Section: Resultsmentioning

confidence: 99%

On the ability of the Viking gas chromatograph–mass spectrometer to detect organic matter

Biemann

2007

Proc. Natl. Acad. Sci. U.S.A.

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] claims to show that the Viking GCMS (gas chromatograph-mass spectrometer) experiment, which carried out a search for organic matter at the surface of Mars in 1976, ''may have been blind to low levels of organics.'' To rebut this assertion, the Viking experiment, test data, and results on Mars are reviewed, and the fallacies in the design, execution, and interpretation of the new experiments presented by Navarro-Gonzalez et al. are critically examined.

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Section: Resultsmentioning

confidence: 99%

On the ability of the Viking gas chromatograph–mass spectrometer to detect organic matter

Biemann

2007

Proc. Natl. Acad. Sci. U.S.A.

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“…The abundance of Li provides a test of the sources of uid mobile elements in the soils, including sulfur and chlorine, which have been known since Viking. 61 Models for the origin of these mobile elements in the soils include volcanic aerosols and hydrothermal uids. 62 The lack of enrichment of the present soils in Li, which is highly uid-mobile, is consistent with the limited inux of subsurface ground waters, or neutral chloride hydrothermal uids.…”

Section: Soil Analysismentioning

confidence: 99%

ChemCam activities and discoveries during the nominal mission of the Mars Science Laboratory in Gale crater, Mars

Maurice

Clegg

Wiens

et al. 2016

J. Anal. At. Spectrom.

150

111

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At Gale crater, Mars, ChemCam acquired its first laser-induced breakdown spectroscopy (LIBS) target on Sol 13 of the landed portion of the mission (a Sol is a Mars day). Up to Sol 800, more than 188 000 LIBS spectra were acquired on more than 5800 points distributed over about 650 individual targets. We present a comprehensive review of ChemCam scientific accomplishments during that period, together with a focus on the lessons learned from the first use of LIBS in space. For data processing, we describe new tools that had to be developed to account for the uniqueness of Mars data. With regard to chemistry, we present a summary of the composition range measured on Mars for major-element oxides (SiO 2 , TiO 2 , Al 2 O 3 , FeO T , MgO, CaO, Na 2 O, K 2 O) based on various multivariate models, with associated precisions.ChemCam also observed H, and the non-metallic elements C, O, P, and S, which are usually difficult to quantify with LIBS. F and Cl are observed through their molecular lines. We discuss the most relevant LIBS lines for detection of minor and trace elements (Li, Rb, Sr, Ba, Cr, Mn, Ni, and Zn). These results were obtained thanks to comprehensive ground reference datasets, which are set to mimic the expected mineralogy and chemistry on Mars. With regard to the first use of LIBS in space, we analyze and quantify, often for the first time, each of the advantages of using stand-off LIBS in space: no sample preparation, analysis within its petrological context, dust removal, sub-millimeter scale investigation, multi-point analysis, the ability to carry out statistical surveys and whole-rock analyses, and rapid data acquisition.We conclude with a discussion of ChemCam performance to survey the geochemistry of Mars, and its valuable support of decisions about selecting where and whether to make observations with more time and resource-intensive tools in the rover's instrument suite. In the end, we present a bird's-eye view of Cite this:

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“…§ ca a~:: '5 though the sulfur content was higher [B. C. Clark et al, 1976]. clods of 50% [B. C. Clark et al, 1976]. Thus it appears that the 0:: Figure la): the upper two trenches were excavated on sols 8 (upper left, XRFS 1) and 14 (upper right, GCMS 2).…”

Section: Vl-1mentioning

confidence: 99%

“…§ ca a~:: '5 though the sulfur content was higher [B. C. Clark et al, 1976]. clods of 50% [B. C. Clark et al, 1976].…”

Section: Vl-1mentioning

confidence: 99%

Surface materials of the Viking landing sites

Moore¹,

Hutton²,

Scott³

et al. 1977

J. Geophys. Res.

126

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Martian surface materials viewed by the two Viking landers (VL-1 and VL-2) range from fine-grained nearly cohesionless soils to rocks. Footpad 2 of VL-1, which landed at 2.30 m/s, penetrated 16.5 cm into very fine grained dunelike drift material; footpad 3 rests on a n:icky soil which it penetrated "'3.6 cm. Further penetration by footpad 2 may have been arrested by a hard substrate. Penetration by footpad 3 is less than would be expected for a typical lunar regolith. During landing, retroengine exhausts eroded the surface and propelled grains and rocks which produced craters on impact with the surface. Trenches excavated in drift material by the sampler have steep walls with up to 6 cm of relief. Incipient failure of the walls and failures at the end of the trenches are compatible with a cohesion near 10-10 2 N/m 2 • Trenching in rocky soil excavated clods and possibly rocks. In two of five samples, commanded sampler extensions were not achieved, a situation indicating that buried rocks or local areas with large cohesions (~ 10 kN/m 2 ) or both are present. Footpad 2 ofVL-2, which landed at a velocity between 1.95 and 2.34 m/s, is partly on a rock, and footpad 3 appears to have struck one; penetration and leg strokes are small. Retroengine exhausts produced more erosion than occurred for VL-1 owing to increased thrust levels just before touchdown. Deformations of the soil by sampler extensions range from doming of the surface without visible fracturing to doming accompanied by fracturing and the production of angular clods. Although rocks larger than 3.0 cm are abundant at VL-1 and VL-2, repeated attempts to collect rocks 0.2-1.2 cm across imbedded in soil indicate that rocks in this size range are scarce. There is no evidence that the surface sampler of VL-2, while it was pushing and nudging rocks "'25 cm across, spalled, chipped, or fractured the rocks. Preliminary analyses of surface sampler motor currents ("'25 N force resolution) during normal sampling are consistent with cohesion less frictional soils (c/J "' 36°) or weakly cohesive frictionless soils (C < 2 kN/m 2 ). The soil of Mars has both cohesion and friction.

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Inorganic Analyses of Martian Surface Samples at the Viking Landing Sites

Cited by 195 publications

References 16 publications

On the ability of the Viking gas chromatograph–mass spectrometer to detect organic matter

On the ability of the Viking gas chromatograph–mass spectrometer to detect organic matter

ChemCam activities and discoveries during the nominal mission of the Mars Science Laboratory in Gale crater, Mars

Surface materials of the Viking landing sites

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