Ashwin R. Vasavada Jet Propulsion Laboratory California Institute of Technology

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In Situ Analysis of Martian Phyllosilicates using
the CheMin Mineralogical Instrument on Mars
Science Laboratory
David Blake, Dave Bish, Steve Chipera, Dave
Vaniman, Philippe Sarrazin and Marc Gailhanou
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NASAs Mars Exploration Program
Recent missions have discovered and studied a
great diversity of environments, including those
with evidence of past liquid water

• Future missions are likely to be focused on
  returning samples or detecting extant life
• The Mars Science Laboratory extends past
  investigations and enables future missions by
  characterizing the habitability of a site, i.e.,
  its potential to support microbial life

The data/information contained herein has been
reviewed and approved for release by JPL Export
Administration on the basis that this document
contains no export-controlled information.
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MSL - MER Comparison
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MSL Size Comparison
2009 MSL Rover
The data/information contained herein has been
reviewed and approved for release by JPL Export
Administration on the basis that this document
contains no export-controlled information.
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Sample Acquisition, Processing, Handling
Two-Meter Robotic Arm
The SA/SPaH has the following capabilities

• Brush rock surfaces
• Place and hold contact instruments
• Acquire samples of rock or regolith via powdering
  drill and scoop
• Sieve samples into fines and deliver the
  processed material to the analytical lab
  instruments
• Provide the opportunity to observe sieved samples

Scoop
APXS
Sieves
Drill
MAHLI
Brush
The data/information contained herein has been
reviewed and approved for release by JPL Export
Administration on the basis that this document
contains no export-controlled information.
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MSL Candidate Landing Sites
Nili Fossae Trough
Mawrth Vallis
Gale Crater
North MeridianI
Miyamoto crater
Holden Crater
Eberswalde Crater
Higher-priority sites are black, others are
white. Black lines show 45º latitude.
The data/information contained herein has been
reviewed and approved for release by JPL Export
Administration on the basis that this document
contains no export-controlled information.
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Chemistry Mineralogy (CheMin)
Principal Investigator David Blake NASA Ames
Research Center
CheMin derives definitive mineralogy

• X-ray diffraction (XRD) standard technique for
  laboratory analysis
• Identification and quantification of minerals in
  geologic materials (e.g., basalts, evaporites,
  soils)

The data/information contained herein has been
reviewed and approved for release by JPL Export
Administration on the basis that this document
contains no export-controlled information.
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Mineralogy - Elucidating the Past

• Minerals are thermodynamic phases, and mineral
  equilibria can be used to determine the p,t,x
  environment of formation.
• Solid state transformations are sluggish, so
  relict mineralogy can be used to identify ancient
  environments.
• Relict biological information may be cryptic
  mineralogy can be used to choose candidate rocks
  which are likely to contain evidence of
  biogenicity.
• Weathering diagenesis may leave only the
  mineral component of a biological process.

Anything older than a few 106 years (99.5 of
Mars geologic history) either is a rock, or can
only be interpreted in term of the rocks that
enclose it.
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The CheMin Flight Instrument
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Sample wheel and sample holders
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150 µm grains flow like a liquid when shaken at
2khz - all grains are exposed to the beam in all
orientations even though the beam is smaller than
the average grain size.

• Sample movement - key to the analysis

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CheMin Flight Hardware
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Angular detection range 5 to 55 2? Co??
Low angle detection is critical for the
characterization of clay minerals.
XRD pattern of non purified Silver Behenate
CH3(CH2)20COO-Ag. First ring d00158.38Å, 1.75
2??Co K?
XRD pattern of a Smectite (SWa-1) with trace of
quartz.
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2? range and resolution Complex Mars
Lithology Mineral model of Peace Outcrop,
Columbia Hills (Ming et al., 2006)
Seven minerals modeled from APXS data
BULK ROCK Although there are many close peaks at
higher 2?, some isolated and distinctive peaks
can be found at 2? values below 25. However,
confirmation based on a single peak is seldom
possible.
Complex structures have many peaks
Simple cubic structures have few peaks
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2? range and resolution Complex Mars
Lithology CheMin analysis of Peace Outcrop at
various resolutions
Minerals in the Peace Outcrop (from previous
slide I100 peaks all at same scale)
Curtis Chen model, simulating degradation of FWHM
by thickening sample from 160µm to 500µm
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2? range and resolution Complex Mars
Lithology CheMin analysis of Peace Outcrop at
various resolutions
Although the kieserite (-111) peak is still
identifiable at 21.5 2?, identification of
kieserite triplet at 30-32 2? is lost as FWHM
goes from 0.35 to 0.40. Presence of kieserite
is suspected but not confirmed if FWHM is worse
than 0.35.
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CheMin Results Rietveld refinement of Andesite
Andesite quantitative analysis Mineral Conc.
(1s) Albite 0.12 (.01) Labradorite 0.58
(.01) Enstatite 0.1 (.01) Augite 0.06
(.01) Cristobalite 0.12 (0.01) Dolomite 0.01
(0.003) Forsterite 0.02 (0.00 Total 1.01
(.015) Refined lattice parameters for
Albite, Labradorite, Enstatite, Augite,
Cristobalite
Energy-filtered 2-D XRD pattern
Diffractogram from XRD pattern
X-ray Fluorescence spectrum for Andesite
Rietveld refinement of Andesite pattern
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Accuracy and Precision Alignment of CheMin with
the capabilities of other MSL analytical
instruments
To maximize the science return from MSL, the
precision and accuracy of CheMin should match
that of ChemCam and APXS
Specified Level 2 Performance for MSL
MSL instrument accuracy Precision, MDL
CheMin 15 10, 3
ChemCam 10 -
APXS 10-15 5-20
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Quantitative analysis of volcanic soil with CheMin
Sample Hawaiian soil (Dick Morris sample 740).
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Accuracy and Precision CheMin 4 vs. controlled
mineral mixtures clay-rich evaporite example.
Synthetic Clay-bearing Evaporite EVAP-02 FULLPAT
Analysis
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Silica Deposits - how can they be discriminated
by XRD/XRF?
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CheMin Instrument Heritage
2002-03
2004-06
1991-96
NASA benchtop lt100kg
NASA/inXitu field prototype 30kg
NASA Proof of concept gt500kg
Field instrument
Mars instrument
2007
2005-09
inXitu Terra, 15kg
NASA/JPL flight system, 10kg
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Svalbard, Norway Aug 2006

• hypothesis generation and testing in the
  field
• ID of ephemeral phases
• down-selection of returned samples

Dave Bish performing the first quantitative
mineralogical analysis in the field -
Spitsbergen, Norway 2006
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Svalbard, Norway Aug 2007
August 2007
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Rover operations testing
Rover operations simulation on the slope of the
Sverrefjell volcano.
Snowy rock
Sverrefjell volcano
loosely consolidated basaltic cinder outcrop with
a white cement. Principally glass with some
olivine, cemented by magnesite.
Snowy Rock is a granite or sediment that has
been metamorphosed to gneiss. Major phases
include biotite, anorthite and quartz.
Soil under Snowy Rock is principally glass with
5-10 olivine and a clay mineral.
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British Columbia, Mar 2008
Meridianiite, MgSO4.11H2O stable with a
saturated brine or with ice, melts above 2C
into Epsomite and water.
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Terra results from the field (15 min.
integration)too warm for Meridianiite

• Rietveld refinement
• 27 epsomite MgSO4-7H2O
• 38 mirabilite Na2SO4-10H2O
• 25 thenardite Na2SO4
• 9 hexahydrite MgSO4-6H2O

Laboratory XRD analysis two weeks later

• epsomite MgSO4-7H2O
• konyaite Na2Mg (SO4)2-5H2O

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Effluorescent Minerals, acid sulfates
Hydronian jarosite
Copiapite coquimbite
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First light on the flight instrument