The Latest from the Mars Exploration Rovers

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The Latest from the Mars Exploration Rovers
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Spirit at Gusev Crater
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Primary goal of Mars exploration Search for
water on Mars
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Summary Orbital photography shows evidence for
water on ancient Mars
Also evidence for large standing bodies of water
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MER Landing Sites Gusev Crater (Spirit) and
Meridiani Planum (Opportunity)

• http//marsonweb.nas.nasa.gov/landingsites/mer2003
  /mocs

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MER Landing sites Gusev crater (Spirit) and
Meridiani Planum (Opportunity)
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Landing Sites for Spirit and Opportunity
Spirit
Opportunity
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Mineralogy Key to hydrological history of Mars

• Magnetite Fe3O4
• Hematite Fe2O3
• Olivine Fe2SiO4
• Pyroxine CaFeSi2O6

Minerals tell about hydrological history, what
chemical reactions were occurring
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Measurements of mineral structure via the
Mossbauer Effect
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Radioisotope selection for MER

• 57Co -gt 57Fe -gt 57Fe 14.4 keV
• Iron dominant element in rocks, good
  mineralogical diagnostic
• 57Co has half life of 271 days. A challenge for
  interplanetary missions

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How does Mossbauer Effect tell you about mineral
structure of Mars rocks?
Klingelhoefer et al 2003, JGR 108, E12, ROV 8
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Transmission versus scattering Mossbauer Effect
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MIMOS II experiment on MER
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The MIMOS II Instrument
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Mossbauer spectra of Mars rocks from MER
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More Mossbauer spectra from Mars
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Results from MER spacecraft

• Evidence of water at Meridiani from the outset
  haematite chondrules, sedimentary rocks with
  chemically weathered compositions there are
  other possible scenarios they all require liquid
  water and acidic conditions.
• Early results from Gusev seemed to argue against
  water high abundance of pristine olivine. the
  ubiquitous presence of olivine in the soil
  suggests that physical rather than chemical
  weathering processes

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Recent results from MER (cont)

• More recent results from Gusev, coatings on rock
  with 2-5 times high S Cl concentrations than
  interior, crystalline haematite.
• The physical and chemical characteristics
  provide evidence for limited by unequivocal
  interaction between water and the volcanic rocks
  of the Gusev plains