The Phoenix Flap

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The Phoenix Flap
MECA
TEGA

• Emily Lakdawalla
• The Planetary Society

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Phoenix MECA WCL

• Wet Chemistry Laboratory
• Four single-use beakers
• 1 cc sample is delivered into 30-mL beaker of
  solution
• Beaker heated to 25C, solution stirred
• Sensors take readings at intervals

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MECA WCL parts
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Phoenix WCL sensors

• Cl- (2 sensors)
• Br- (2 sensors)
• I- (2 sensors)
• NO3-
• SO4 (using Ba ISE)

• Pb/Cu/Cd/Zn/Fe
• Cyclic Voltammetry
• ORP (redox potential)
• Temperature
• Li Reference (3 sensors)
• Conductivity
• pH (3 sensors)

• K
• Ca2
• Mg2
• NH4
• Na

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Phoenix TEGA

• 8 single-use ovens
• Mass Spectrometer and Differential Scanning
  Calorimeter
• 3 heating cycles
• In first 2, calorimetry is whats important, only
  10-20 selected masses are scanned
• In last, to 1000C, evolved gases are analyzed in
  detail by mass spec

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Inside TEGA
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Inside TEGA
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Sample locations
MECA Rosy Red Sol 30
Sol 43
Sol 14
TEGA Baby Bear Sol 12
MECA Sorceress Sol 41
(later) TEGA Wicked Witch Sol 64
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Baby Bear to oven 4, sol 12
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Wicked Witchto oven 0,sol 64
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Wheres the perchlorate?

• WCL saw strong signal in both samples, taken from
  Snow White area.
• TEGA saw inconclusive signal in Baby Bear, no
  signal in Wicked Witch.

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Whats perchlorate?

• 1 chlorine 4 oxygens, ClO4-
• An anion, usually found bonded to cation like
  magnesium, sodium, ammonium
• Most Earth life doesnt like it, but microbes in
  Atacama soil are perfectly happy to have it around

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How WCL sees perchlorate

• WCL has a nitrate sensor that is actually much
  more sensitive to perchlorate than it is to
  nitrate.

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How TEGA sees perchlorate

• In early heating it saw oxygen driven off.
• It wasnt looking for chlorine being driven off
  in the Baby Bear sample.
• After the WCL results, it looked for chlorine in
  Wicked Witch, didnt see it.
• But that doesnt rule out perchlorate.