Author Topic: Mining and Processing Lunar Ice  (Read 13471 times)

Offline DLR

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Mining and Processing Lunar Ice
« on: 09/26/2011 03:49 PM »
What would be required to mine Lunar ice, melt it and split it into hydrogen and oxygen?

Well, if the ice is bound into lose regolith, the regolith could be scooped up and transported to a solar concentrator, where the water would be evaporated, captured and electrolysed. The "slag" regolith would be dumped into a nearby crater.

But what about ice sheets, 100% pure water ice and other volatiles, which might exist in the permanently shadowed Lunar craters? How would you mine and process that? Cut blocks of ice and transport them to the solar furnace? Or melt into the ice sheet using a nuclear-heated "straw", which would capture most of the evaporating ice?


Offline Hop_David

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Re: Mining and Processing Lunar Ice
« Reply #1 on: 09/27/2011 04:26 AM »
What would be required to mine Lunar ice, melt it and split it into hydrogen and oxygen?

Well, if the ice is bound into lose regolith, the regolith could be scooped up and transported to a solar concentrator, where the water would be evaporated, captured and electrolysed. The "slag" regolith would be dumped into a nearby crater.

But what about ice sheets, 100% pure water ice and other volatiles, which might exist in the permanently shadowed Lunar craters? How would you mine and process that? Cut blocks of ice and transport them to the solar furnace? Or melt into the ice sheet using a nuclear-heated "straw", which would capture most of the evaporating ice?

Awhile back there was this thread: Mining Lunar Ice

As I recall, Warren mentioned heavy equipment companies like Caterpillar are already studying mining equipment for the moon. One of the major obstacles is extreme cold makes metal brittle. Although most of the machine would be in vacuum (a good insulator), the treads, shovel blades, drill bits etc. would be making contact with the 30 degree K ice. Warren had cited some nickel alloys that seem to do well at these extreme temperatures.

One of the problems was getting power to the heavy equipment at the bottom of dark craters. Warren had suggested, since the mine was to produce hydrogen and oxygen, the heavy equipment carry hydrogen fuel cells.

Also as I recall, Fornaro had suggested containers be placed at the focus of parabolic mirrors which would be on turntables to follow the sun during it's 28 day circuit. It seems to me Bill White also had suggested something like this in other threads.

Besides heat to melt ice, electricity would be needed perform electrolysis. One of the bottlenecks was getting enough electricity from a power source of plausible mass.

But that's just my (fallible) memory. I don't feel up to re-reading that thread at the moment.

If the ice has volatiles in anything like the same proportions as the LCROSS ejecta, I believe a lot of fractional distillation would be needed. Setting up a fractional distillation plant on the moon would be... interesting.
« Last Edit: 09/27/2011 04:41 AM by Hop_David »

Offline JohnFornaro

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Re: Mining and Processing Lunar Ice
« Reply #2 on: 09/27/2011 01:42 PM »
Not bad on the memory there.  One clarification:

The parabolic mirror array, rotating on its vertical axis, was intended to heat steam to a turbine/generator prime mover, to generate electricity for the mining equipment in the floor of the crater.  There's a small picture of it here:

http://forum.nasaspaceflight.com/index.php?topic=23661.msg695005#msg695005
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Offline go4mars

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Re: Mining and Processing Lunar Ice
« Reply #3 on: 09/27/2011 08:15 PM »
More Alternatives:

Or seal the lips of a bag to the ice and have a microwave emmitter inside the bag.  Point it at the ice, turn it on, and let the resultant vapour re-freeze on the inside of the bag.   

Something similar could be done with an electrically polarized long tube (where the polarity of water sucks it to the sides of the tubes to freeze).  The benefit of this way is that instead of microwave radiation, sunlight could simply be reflected down the tube.  Production could be expanded by making lenses from ice at that location (within a transparent sheath to prevent sublimation).

These would work on Mars also. 
« Last Edit: 09/27/2011 08:18 PM by go4mars »
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Offline Andrew_W

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Re: Mining and Processing Lunar Ice
« Reply #4 on: 09/27/2011 08:24 PM »
I thought it would just be done with a big mirror on a near by peak reflecting sun light onto the concentrator of a solar oven heating the ground below it and collecting the volatiles released The volatiles would then be pumped out of the crater to a sunny location for distillation, gases like N2 carried out with the water.
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Offline JohnFornaro

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Re: Mining and Processing Lunar Ice
« Reply #5 on: 09/28/2011 03:17 PM »
Not much N2, mind you.  It will be a problem in creating the atmo for the base, which should be as close to a normal atmo as possible, not as close to human extremophile living as possible.

Where does the nitrogen come from?
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Offline Hop_David

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Re: Mining and Processing Lunar Ice
« Reply #6 on: 09/28/2011 06:17 PM »
Not much N2, mind you.  It will be a problem in creating the atmo for the base, which should be as close to a normal atmo as possible, not as close to human extremophile living as possible.

Where does the nitrogen come from?

See The LCROSS brew. Kamaz got these concentrations from 5 papers in the Oct. 22, 2010 edition of Science journal:

N   6.6000%
CO   5.7000%
H2O   5.5000%
Zn   3.1000%
V   2.4000%
Ca   1.6000%
Au   1.6000%
Mn   1.3000%
Hg   1.2000%
Co   1.0000%
H2S   0.9213%
Fe   0.5000%
Mg   0.4000%
NH3   0.3317%
Cl   0.2000%
SO2   0.1755%
C2H4   0.1716%
CO2   0.1194%
C   0.0900%
Sc   0.0900%
CH3OH   0.0853%
S    0.0600%
B   0.0400%
P   0.0400%
CH4   0.0366%
O   0.0200%
Si   0.0200%
As   0.0200%
Al   0.0090%
OH   0.0017%

You can see there was nitrogen as well as ammonia in the LCROSS ejecta. Do the ice sheets in the anomalous craters have volatiles in the same proportions? Presumably the ice sheets came from the same comets as the LCROSS ice. So it's my belief the sheets have lots of CHON.

« Last Edit: 09/28/2011 06:19 PM by Hop_David »

Offline Warren Platts

Re: Mining and Processing Lunar Ice
« Reply #7 on: 09/28/2011 06:45 PM »
Not much N2, mind you.  It will be a problem in creating the atmo for the base, which should be as close to a normal atmo as possible, not as close to human extremophile living as possible.

Where does the nitrogen come from?

Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.
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Offline Hop_David

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Re: Mining and Processing Lunar Ice
« Reply #8 on: 09/29/2011 07:47 PM »
Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.

Isn't that an extreme fire hazard?

Offline baldusi

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Re: Mining and Processing Lunar Ice
« Reply #9 on: 09/29/2011 09:12 PM »
Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.

Isn't that an extreme fire hazard?
It's the same amount of O2 that's in the current atmosphere. So the partial pressure is the same, or the amount of oxygen per cubic meter. It does require acclimatization. And I'm not sure the long term effects on health are studied well enough.

Offline N45deg

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Re: Mining and Processing Lunar Ice
« Reply #10 on: 09/30/2011 12:15 AM »
Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.

Isn't that an extreme fire hazard?
It's the same amount of O2 that's in the current atmosphere. So the partial pressure is the same, or the amount of oxygen per cubic meter. It does require acclimatization. And I'm not sure the long term effects on health are studied well enough.
A pure O2 environment in any gravity situation would be an extreme fire hazard even at 5 psi. In a gravity environment, hot gasses rise, allowing more pure O2 to feed the fire and it rapidly expands.  In a zero G environment, the fire forms a sphere and tends to smother itself.

Offline Patchouli

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Re: Mining and Processing Lunar Ice
« Reply #11 on: 09/30/2011 12:54 AM »
Not much N2, mind you.  It will be a problem in creating the atmo for the base, which should be as close to a normal atmo as possible, not as close to human extremophile living as possible.

Where does the nitrogen come from?

Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.


For a base yo want a buffer gas as prolonged a pure O2 atmosphere can cause repository problems such as Atelectasis or alveolar collapse.
http://en.wikipedia.org/wiki/Atelectasis
This is why Skylab used a 70% O2 and 30% N2 atmosphere at 5psi.

If you want to be EVA friendly you could reuse the old Skylab atmosphere composition.
Though since an early base would likely be using systems derived from LEO vehicles and stations it may require use of an atmosphere close to 1 ATM to meet fire proofing needs and to keep the electronics cool.
Plus Bigelow type modules depend on their inflation pressure for structural support.
7 to 10 psi with O2 providing around 3.5 psi of the pressure might be a good compromise here.
« Last Edit: 09/30/2011 12:59 AM by Patchouli »

Offline Jorge

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Re: Mining and Processing Lunar Ice
« Reply #12 on: 09/30/2011 01:07 AM »
Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.

Isn't that an extreme fire hazard?
It's the same amount of O2 that's in the current atmosphere. So the partial pressure is the same, or the amount of oxygen per cubic meter.

Incorrect. PPO2 in the current atmosphere is around 3 psi, not 5.
JRF

Offline 93143

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Re: Mining and Processing Lunar Ice
« Reply #13 on: 09/30/2011 01:15 AM »
Bah.  Just develop a full-pressure suit.  It can't be that tough...

Offline Patchouli

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Re: Mining and Processing Lunar Ice
« Reply #14 on: 09/30/2011 01:23 AM »
Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.

Isn't that an extreme fire hazard?
It's the same amount of O2 that's in the current atmosphere. So the partial pressure is the same, or the amount of oxygen per cubic meter.

Incorrect. PPO2 in the current atmosphere is around 3 psi, not 5.

At 5 psi you can have some buffer gas I used to think it would have to be helium on the Moon but the LCROSS data shows this is unnecessary as the Moon does have sizable nitrogen deposits.
« Last Edit: 09/30/2011 01:23 AM by Patchouli »

Offline N45deg

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Re: Mining and Processing Lunar Ice
« Reply #15 on: 09/30/2011 01:42 AM »
Nah, you want to run basically pure O2 at about 5psi; otherwise it's too much of a pain to do EVA's. Witness what a pain in the arse it is to do an EVA at ISS; meanwhile, the Apollo boys were going out every day.

Isn't that an extreme fire hazard?
It's the same amount of O2 that's in the current atmosphere. So the partial pressure is the same, or the amount of oxygen per cubic meter.

Incorrect. PPO2 in the current atmosphere is around 3 psi, not 5.

At 5 psi you can have some buffer gas I used to think it would have to be helium on the Moon but the LCROSS data shows this is unnecessary as the Moon does have sizable nitrogen deposits.
You have to have some inert gas in the mix. A pure O2 in  gravity environment is a disaster waiting. See my above post.

Offline JohnFornaro

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Re: Mining and Processing Lunar Ice
« Reply #16 on: 09/30/2011 01:57 PM »
Quote
N   6.6000%

I did forget about that, especially the ammonia.  I was thinking of nitrogen bound in the rocks.  I need to re-read LCROSS info.  The N2 will have to be saved for the atmo of the lunar base.  Pure O2 wouldn't be good, both for the fire hazard as well as the stark difference from Earth's atmo.  My feeling is that the base should be as familiar an environment as it can be, and that atmo is a key factor here.  The challenge is to establish a permanent colony, which implies birth.  The current health challenges are not well understood; they should follow my advice:

Minimize the variables in the new environment as much as possible.  Then the effects can be better isolated and understood.

The EVA issue will sort itself out, I believe.  They will be minimized.  Workers should be inside of a transporter/crawler/loader/etc. in a shirtsleeve environment.  Items needing repair will largely be brought indoors.  I'm thinking the absolute pressure should be about the same as a 6000 foot terrestrial elevation, which requires hardly any acclimitization.
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Offline Proponent

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Re: Mining and Processing Lunar Ice
« Reply #17 on: 10/01/2011 03:45 AM »

Offline Warren Platts

Re: Mining and Processing Lunar Ice
« Reply #18 on: 10/01/2011 10:12 AM »
Quote
N   6.6000%
Pure O2 wouldn't be good, both for the fire hazard as well as the stark difference from Earth's atmo.

They just said above that Skylab used a N2/O2 mixture at 5 psi.


 
Quote
My feeling is that the base should be as familiar an environment as it can be, and that atmo is a key factor here....The EVA issue will sort itself out, I believe.  They will be minimized. 

My belief is that would be incorrect. Having humans on the base vastly increases its functionality. It would be foolish to tie one arm behind their backs unnecessarily. There is no evidence that the Apollo astronauts or the Skylab astronauts suffered ill effects from a 5 psi "atmo". Skylab tours lasted several months each--I'm sure you remember that far back.

The only reason ISS is at sea level pressure is because it was a necessary compromise in order to bring the Russians on board because their legacy equipment was all 1 atmosphere for some reason.
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Offline JohnFornaro

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Re: Mining and Processing Lunar Ice
« Reply #19 on: 10/01/2011 12:37 PM »
Quote from: Warren
They just said above that Skylab used a N2/O2 mixture at 5 psi.

Yes, they did.  Just because something can be done, doesn't mean that it's the right way to do it.  My feeling is still that as much terrestrial familiarity that can be given to the human body should be given.  The environment is strange enough as it is, and health effects are not clear.  Eliminating as many variables as is possible will focus the health research on the remaining issues.  The long term goal is colonization, and the showstopper for the moment is long term health.  Long term ulitmately means birth to death.  This, were I to have my way, would be the underlying theme of HSF; the lunar base would be the first experiment in determining the viability of human life off planet.

Quote
Having humans on the base vastly increases its functionality.


Of course it does.  This thread hasn't argued otherwise.  My thinking is that EVA's will be minimized.  That is, girlz in suits going outside to pick up rocks or change the oil in the Joy miner.  The work that has to be done is industrial scale mining in a harsh environment; the equipment probably should and will be operated by people in a shirtsleeve environment.  There are two ways that I envision this; one, a Joy miner with a cab, or two, a robotic Joy miner teleoperated from the base.  If the first, then standardized docking becomes higher on the critical path.

That is, if Joy wins the competitive bid on the miner.
Sometimes I just flat out don't get it.

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