Different Oxygen extraction methods were considered:

1
A basic introduction to Molten Silicate
electrolysis

• Different Oxygen extraction methods were
  considered

2
A basic introduction to Molten Silicate
electrolysis

• Molten silicate (SiO2) electrolysis advantages
  over the other reactions
• normal reducing agents not available on the moon
  gt electrolysis
• high concentration of silicates in the lunar
  regolith (45)
• relatively high efficiency
• ease of separation of oxygen (just melt it, and
  then electrolyze it!)
• Disadvantages
• high temperatures and high power required for
  reaction to take place

3
A closer (more detailed) look to the reaction
Cathode Reactions

Anode Reaction
Reaction T 1400-1450C Reaction P Lunar
atmosphere gt vacuum
4
Original procedure outline

• Sifting Get rid of massive chunks of regolith.
• Conductivity separation chamber Use of this
  separation technique has been reconsidered
  looking into spectroscopy instead.
• Reaction chamber
• Oxygen Separation
• Oxygen Analyzer For analysis purposes.
• Oxygen collection chamber Compress and store
  produced oxygen.

5
Modified procedure outline
6
A. Sifting chamber

• The idea behind it
• To get rid of massive chunks of regolith
• We have feed-thrus with small cross sections we
  dont want big chunks to get stuck in them and
  clog them
• Also considering variation of mineral
  consentration vs. grain size that could
  potentially affect our process efficiency
• ? Big chunks take longer to melt, use up too much
  power might not even end up melting during our
  reaction procedure

7
B. Conductivity separation chamber

• Initially, the idea behind it
• We only wanted to heat up soil that will give us
  O2. Energy should not be used up in heating up
  soil that will not melt or electrolyze, since it
  will not serve the purpose of oxygen extraction.
• The process required heating soil to 700C to
  increase conductivity
  
• Due to heating, gases mostly H2,
  H2O, CF4 (from solar wind, etc) that are in lunar
  soil are liberated)
• However
• ! After investigating
  conductivities for silicates and
• O2-rich substances on
  the moon,
• we concluded that this process
• will not cause any considerable
• increase in overall O2 production
• efficiency

Alternative method
8
B. Alternative method to Conductivity
separationSoil Spectroscopy

• The idea behind it
• O2-rich substances on the moon that melt within
  a lower temperature range (1400-1450C) and
  efficiently give out oxygen, can be identified by
  the wavelengths they reflect when undergoing
  spectroscopy.
• These wavelengths are differentiated enough
  between different substances, and the substances
  are scattered on the moon surface in such a way
  that they allow for spectroscopy to be used for
  selectively acquiring the right type of soil for
  our process.
• The process
• Will require a spectroscope attached to the
  mechanical arm which will scan lunar soil and
  identify regions with desired type of soil
• Through a controller, the mechanical arm will
  only be allowed to pick up that soil that is
  desired for greater efficiency

9
C. Reaction chamber
This is where the reaction takes place! I.e.,
where the soil (mainly silicates) is heated up to
melting point, and then electrolysis occurs,
giving out oxygen
Remember T 1400-1450C P vacuum
Also, at this point we want to be able to get rid
of all the processed material, after the reaction
is completed (Waste disposal, which is what the
valve is for)
10
C. Initial Reaction chamber setup
Most probable heating element materials tungsten
Also changing the geometry to coil
11
C. Reaction chamber - Electrodes

• The idea behind it
• We used the cylindrical shape (cathode surrounds
  anode) to allow collecting the O2 that is
  produced on the anode and transferring it outside
  the chamber

Initial setup
Electrodes embedded throughout the whole volume
of the fluid
Possible anodes considered
Iridium or Pt
Possible cathodes considered C or Pt with Fe-Si
coating
Modified (new) setup More surface area
(total) Only one opening for heat to escape Can
afford losing one electrode to clogging No need
for stirring viscous fluid
Problems we are facing Accumulation of Si, and
formation of Si-Pt alloy on cathode, which could
potentially clog/destroy the electrode
12
C. Reaction chamber Electrodes (new setup)
Modified (new) setup More surface area
(total) Only one opening for heat to escape Can
afford losing one electrode to clogging No need
for stirring viscous fluid
Electrodes embedded throughout the whole volume
of the fluid
13
C. Reaction chamber Insulation initial design

• The idea behind it
• Heat loss prevents from reaching the temperature
  we need for reaction to take place.
• Since we have power limits, we need to save as
  much heat as we can
• Heat loss is both due to
• conduction and radiation
• (Radiated heat sT4)
• Initial design (on the left) has
  been reconsidered
• New design more radiation shielding

14
C. Reaction chamber Insulation new design
New design more radiation shielding, more
vacuum, less solid contact
Possible container materials Tantalum, or
Molybdenum Mo forms an oxide that evaporates
easily Possible reflective layers Al, Au, Ag,
or Pt Possible insulator materials Alumina
(Al2O3), or Zirconia (ZO2) stabilized with
Yttria (Y2O3)
15
D. Oxygen separation chamber

• The idea behind it
• Along with O2, other gases could potentially
  escape our reaction chamber
• Our goal is to extract O2, so we have to separate
  those gases out
• The diagram on the left depicts an O2 separator
  it uses membranes that are selectively permeable
  to O2 works with low-P gas and T700C

Cerametic Inc. Ion Transport Membrane Cost
10,000
16
E. Gas analyzers/O2 sensor

• The idea behind it
• After we separate the O2, we want to
  see what efficiency we have by looking at purity
  of O2
• If we know volume, we can calculate
  the O2 produced
• Also, we can see if any O2 is lost in previous
  stages

17
F. Oxygen collecting chamber

• The idea behind it
• Condense O2 by cooling it down and store it or
  compress it (use small, efficient compressor).

Havent started working on it yet!!!!
18
A few more notes
The valves that we are using for our reaction
chamber for disposal have to be able to withstand
the temperature of the molten silicates, as well
as be non-corrosive to them. The valves that we
are using for our reaction chamber for O2
transfer have to be able to withstand the
temperature of the O2 gas, as well as be
non-corrosive to it. For cooling mechanism, we
will try to find a low P, low m compressor.
19
If you have any questions, send an EMAIL to
gkaragio_at_fit.edu