Astronomy 330

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Astronomy 330

• Lecture 15, part 2
• Whats new on Mars

See http//marsrovers.jpl.nasa.gov/10topImages
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Astronomy 330 Two new missions not discussed in
text

• Mars Exploration Rovers (Spirit and Opportunity)
• Mars Express

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Astronomy 330 Spirit and Opportunity

• Sprit first to land in 1/3/2004, Opportunity
  landed 1/24/2004
• Both continue to operate
• Attempting to answer the question of where and if
  liquid water existed on Mars and how it
  influenced the Martian surface

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Astronomy 330 Rovers Summary

• Science instruments on board
• Panoramic Camera
• Miniature Thermal Emission Spectrometer
• Mossbauer Spectrometer (determining mineral
  composition or iron-bearing rocks)
• Alpha particle X-ray Spectrometer (close-up
  analysis of element abundances)
• Magnets (for collecting dust particles which can
  be analysed with other instuments)
• Microscopic imager (close-up images of rocks and
  soil)
• Rock Abrasion Tool (RAT)

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Astronomy 330 The Rovers
See http//marsrovers.jpl.nasa.gov/mission/spacec
raft_surface_rover.html
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Astronomy 330 More about the Rovers

• Landed by deploying parachutes
• Rockets fire just before impact
• Air-bags inflate to allow rover and its landing
  module to bounce across the surface
• As rover comes to a stop, air-bags deflate,
  tetrahedral module opens like petals of a flower

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Astronomy 330 Main discoveries of rovers

• Mars was once a watery place
• Opportunity discovered spherules and salts near
  its landing site
• Also discovered layering in rocks and and
  patterns in rocks indicating water flow

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Astronomy 330

• Four main discoveries indicating water
• First spherules were discovered. Spherules could
  be volcanic in origin or from crater impacts as
  well, but rich in a mineral hematite which forms
  in the presence of water on Earth

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Astronomy 330 Blueberries
http//marsrovers.jpl.nasa.gov/spotlight/20040906.
html
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Astronomy 330 2nd discovery indicating water

• Hydrated Minerals
• Hydrated mineral iron sulfate called jarosite was
  discovered, forms in acidic lakes or hot springs
  on Earth

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Astronomy 330 3rd discovery

• Salts
• High amount of sulfur, chlorine, and bromine
  measured
• These elements expected to be deposited from
  salty water as a shallow, briny lake evaporates

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Astronomy 330 4th discovery

• Randomly oriented cavities in rocks
• Holes left over from original mineral deposits
  which were dissolved in water
• Again, similar formations seen on Earth
• Known as vugs

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Astronomy 330 Vugs
http//marsrovers.jpl.nasa.gov/spotlight/20040906.
html
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Astronomy 330 How much water?

• A lot of water !
• Fine parallel layers that were likely formed by
  water deposited sedimentation

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Astronomy 330 Fine layers in rocks
http//marsrovers.jpl.nasa.gov/spotlight/20040906.
html
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Astronomy 330 For how long was water there?

• A long time!
• Crossbeds and ripple marks in rocks indicate
  that salty water was flowing
• Crossbeds are rocks layers that dip at an angle
  to the main horizontal layers
• Ripple marks are wavelike peaks and troughs

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Astronomy 330 Crossbeds and Ripple marks
ripples
crossbeds
http//marsrovers.jpl.nasa.gov/spotlight/20040906.
html
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Astronomy 330

• All this evidence suggests that Meridiani Planum
  (where Opportunity landed) was perhaps covered by
  a shallow, flowing sea

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Astronomy 330 Mars Express

• European mission
• Went into orbit around Mars 11/22/03
• WEB site http//sci.esa.int/science-e/www/area/in
  dex.cfm?fareaid9
• Image to follow come from the above WEB site
• Many high resolution images (High Resolution
  Stereo Camera)

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Astronomy 330 Mars Express Discoveries
Tectonic cracks near Tharsis bulge
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Astronomy 330 Mars Express Discoveries
Kasei valley, outflow feature, erosion patterns
more consistent with glacial activity than
flowing water
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Astronomy 330
A frozen sea? Looks much like pack ice on Earth
as It break up. Note lack of many craters
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Astronomy 330 Closeup of North Pole, note layers
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Astronomy 330 Volcano near North Pole
Could indicate recent volcanic activity, melting
polar water?
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Astronomy 330 Evidence for Water Ice at South
Pole
CO2
H2O
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Astronomy 330 Rootless cones
Result from subsurface ice which is melted by
volcanic activity and exploded from surface
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Astronomy 330

• Mars express has detected methane above the
  surface of Mars in areas where subsurface ice has
  also shown to be located
• Its has been speculated that this could be due to
  the presence of current bacterial life on Mars OR
  it could be due to volcanism or other geologic
  activity (stay tuned !!!!).

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Astronomy 330 Reading

• Read all the pages following this link
  http//marsrovers.jpl.nasa.gov/spotlight/20040810.
  html
• Browse the images from Mars Express at
  http//sci.esa.int/science-e/www/object/index.cfm?
  fobjectid34532