mining lunar ice

neviden · 2006-08-12 10:24:48

Let us presume that there is ice in permamently dark valeys on north and south lunar poles. It is mixed with dirt and rocks in low concentrations (let us presume 1% of weight is ice, the rest is dirt), and you must deliver water to base where it is used. How would you do it?

I would build base at the top of the mountains which are permamently lit. You have constant sunlight so you can split water into O2 and H2.. I would have a 20 MT rover/digger/transporter, refuel it on the top of the mountain with O2 and H2, then drive to the valeys below.. the digger would probobly weigh around 20 MT, therfore it could cary a lot of dirt. It would have tanks for O2, H2 and H2O, big shovel and even bigger place to carry dirt (it's moon - things are 1/6 earth weight).. It would combine O2 and H2 to power it (and of course it would store that water for reuse), would be automatic or remotly driven (from earth) and localy fixable..

I guess it could easily pick up 30 MT of dirt and drive 10 km, dump it and return to pick up more dirt in one hour. That would mean, that one truck would move 720 MT of dirt a day, containing 7,2 MT of water in it.. you dump this dirt in big black box and seal it.. next you need to heat all of this dirt to 100+ degress celsius.. you do this by simple mirrors that are located at the top of the mountains. since there is no atmosfere on moon it doesn't matter if they are 10 or more km away.. it might be a little tricky seting them up, but since sun moves realy slowly and predictably all you would need are small motors that would move them.. they could be very light.. big box heats up, water boils away, and condenses in cold tanks conected to this box..

all that you would need then is to fill up digger with water and drive it to top of the mountain..

RedStreak · 2006-08-12 14:58:47

If it is simply intermixed with the dust it may be easy to gather. Essentially you use a beefed-up rover with a snow shovel and collection baskets to the sides.

Once collected the dust would have to be sorted as much as possible. A good-old-fashion sifter in one form or another at least. This may vary depending on the exact form of the ice which makes identifying it beforehand definetely vital.

Taking the portion of the dust that is primarily ice then you simply thaw it, either directly with solar light or in a microwave powered by solar panels. Once liquid pump the water through a filter to eliminate the final bits of lunar dust.

As for what to do with the water just store it as H2O I say. In that form alone there'd be plenty of uses for it at a lunar base. Any cryogenic H2 or O2 should be meant as short-term storage for immediate launches otherwise we'd be wasting water - only use electrolosis to break it up when we absolutely need to. It takes more effort and energy even in the shaded regions of the moon to keep O2 and H2 at those temperatures so, again, only when nessicary.

Now if the ice is intermixed with solid rock, which hopefully isn't as likely, then we'd need even tougher equiptment; certainly an automated jackhammer at least. Add rock crushers to the aforementioned extraction process and it'd be mostly the same.

neviden · 2006-08-12 15:20:40

Once collected the dust would have to be sorted as much as possible. A good-old-fashion sifter in one form or another at least. This may vary depending on the exact form of the ice which makes identifying it beforehand definetely vital.

Why sort it? And how do you sort ice from dust?

I don't think there are big plates of ice lying around.. not if 99% of other material is dirt..

Why not just heat everything untill ice is converted into steam, capture and cool this steam and you have pure water.. you don't actualy even need to capture it.. steam is gas and will expand in space, but since you have everything sealed it can expand only to second box, where it will liquefy or become ice again.. you need heat (mirors) and cold (well.. your box is in a place that hasnt seen sun for a long time..)..

Grypd · 2006-08-12 16:01:56

If the ice is mixed with dust then it is the easiest option to get at the water.

Simply collect both and then take them to a spot where you can direct sunlight onto by mirror. Then it will be a case of collecting the steam out of the material. The excess dust now water free is simply ever dumped or used for sintering and turned into building materials.

SpaceBull · 2006-08-14 17:28:31

As for what to do with the water just store it as H2O I say. In that form alone there'd be plenty of uses for it at a lunar base. Any cryogenic H2 or O2 should be meant as short-term storage for immediate launches otherwise we'd be wasting water - only use electrolosis to break it up when we absolutely need to. It takes more effort and energy even in the shaded regions of the moon to keep O2 and H2 at those temperatures so, again, only when nessicary.

I agree. Splitting the water into oxygen and hydrogen is a bad idea. If there is a limited amount of water on the moon then every single drop should be preserved for "organic" purposes. Using it as rocket fuel would be horrible idea. A liter of water split into hydrogen and oxygen will not get you very far, but can on the other hand be sufficient to grow you a decent meal every single week.

SpaceNut · 2006-08-15 21:16:10

Here a resource for what it will take. Scientists Working To Help Astronauts To Breath Moon Dust

Lunar soil is rich in oxides, the most common of which is silicon dioxide, or SiO2, "like beach sand," Cardiff said. Also plentiful are oxides of calcium (CaO), iron (FeO) and magnesium (MgO).
As proof of principle, Cardiff and colleagues used a lens to focus sunlight into a tiny vacuum chamber and heated 10 grams of simulated lunar soil to about 2,500 degrees Celsius (4,500 degrees Fahrenheit).
In their tests, "as much as 20 percent of the simulated soil was converted to free oxygen," Cardiff said. The leftover is called slag, a low-oxygen, highly metallic, often glassy material.

Perfect for solar cell construction and more if you process it as you go.

JoshNH4H · 2008-03-06 09:23:23

To answer this question, how to mine lunar ice at low concentracions, I thought it was self evident: put the dirt in a vacuum jar, and then heat it to 150 C. out comes steam, then dump whatever you don't want.

Terraformer · 2008-03-07 14:20:55

If a Spacecraft took off from the moon burning H2/O2, would the steam turn back into a layer of ice on the launch bad where it could be collected, or reach escape velocity (which I doubt)?

RedStreak · 2008-03-07 14:33:11

If a Spacecraft took off from the moon burning H2/O2, would the steam turn back into a layer of ice on the launch bad where it could be collected, or reach escape velocity (which I doubt)?

You doubt correctly. You're talking steam a few hundred degrees hot in an airless enviorment where the solar wind is supreme. A few atoms at best would resettle if any, and bear in mind what little ice that's on Luna took a few billion to accumulate from comet collisions, each of which only contributed a tiny bit at a time of each comet's mass.

So yeah, snowball's chance in Hell senerio.

Grypd · 2008-04-09 03:55:48

It may be possible to design a launch and landing pad where the exhaust can be captured and some of the volatiles captured. One simple method would be to design a lip around the blast walls of the landing pad to capture this. It may well prove valuable to do this.

And there will be blast walls around any Lunar landing base just to stop any dust on the pad being blasted away and threatening base operations.

GCNRevenger · 2008-04-10 13:48:10

Nah, the rocket doesn't spend enough time near the surface nor has that much thrust, so little in the way of volatiles are released near the surface. And as mentioned previously, at an altitude the solar wind and low gravity will carry away the exhaust, so it won't fall back down again.

Grypd · 2008-04-11 04:29:22

It is true that a lot of the thrust of any launches or landings will not be catchable but if we are using H2/O2 rockets or similar for landing we should try to catch the exhaust on the pads. We already focus a lot of exhausts from Earth based rockets to stop them damaging the pads on launching.

Certainly we will have berms etc around any landing pad to stop dust and exhaust damaging the base etc. Economics indicates we should try to capture and recycle as much as we can of everything we send to the Moon.

Just a proposal to have a curved lip over the edges of the landing pad berms so that some of the rapidly traveling gases can be caught. These gases can go through a simple non return device and out of the Suns rays the natural cold would quickly liquify these gases.

If we capture a few gallons each time its all benefit as the system will be designed to have no need for human supervision

RedStreak · 2008-04-11 12:46:18

Question is will it be cost effective since we have to ship everything to the moon initially and there won't be a single dedicated 'launch pad' on the moon itself.

Grypd · 2008-04-11 15:33:16

True, but then again it is really for the long term when we have permanent bases and all that we can keep matters. Just like we will design packing cases so that they can be at the least composted to provide more resources to an expanding base.

RedStreak · 2008-04-11 15:53:02

True, but then again it is really for the long term when we have permanent bases and all that we can keep matters. Just like we will design packing cases so that they can be at the least composted to provide more resources to an expanding base.

Assuming a permenant base THEN it become a maybe since more local sources/manufacturing could be utilized. However my guess is in the 'interm' stages between tiny outpost and pseudo-colony we'd be talking about vapor being sucked into vents or ice being scrapped off the launch pad.

I still think it would be tricky but if you're going to attempt it I suggest, one way or another, employing a simple, cost-effective method. Just don't expect it to yield as much as ice mining.

Grypd · 2008-04-11 16:18:20

True, but then again it is really for the long term when we have permanent bases and all that we can keep matters. Just like we will design packing cases so that they can be at the least composted to provide more resources to an expanding base.
Assuming a permenant base THEN it become a maybe since more local sources/manufacturing could be utilized. However my guess is in the 'interm' stages between tiny outpost and pseudo-colony we'd be talking about vapor being sucked into vents or ice being scrapped off the launch pad.
I still think it would be tricky but if you're going to attempt it I suggest, one way or another, employing a simple, cost-effective method. Just don't expect it to yield as much as ice mining.

Of course not, there is no chance that any reclaiming of vapour will bare any relation to the amount that mining would garner. But with volatiles being so scarce on the Moon it becomes economic necessity to capture and retain as much as you can.

SpaceNut · 2008-04-11 18:26:06

If the rocket is taking off from the sun lit side of the moon there will be no volitiles to collect as they will not remain from the heating that will happen from the sun.
Now on the dark side these will bew available to retrieve but unless you take off slow there will not be much build up at the launch site.

Grypd · 2008-04-12 05:56:12

If the rocket is taking off from the sun lit side of the moon there will be no volitiles to collect as they will not remain from the heating that will happen from the sun.
Now on the dark side these will bew available to retrieve but unless you take off slow there will not be much build up at the launch site.

The idea is to capture these volatiles very quickly after launch and so stop the sun from having any effect at all. And diffusion is the real problem not the sun as they will be coming out very fast.

A rocket does not instantly take off we have quite a few seconds where the rocket is throttling up before it goes. The thrust will hit the pad and then be forced outwards to protect the rocket. The Berms at the side of the pad will stop any stour on the pad being blasted away and being a hazard. It will also by its nature focus the exhaust plume full of volatiles and it is this focusing that we hope to capture.

But as stated this is a longer term project and for a much mature base where we try to keep costs down as much as possible.

RobS · 2008-04-12 08:14:55

Dr. Michael Duke at the Colorado School of Mines has been thinking about the probems of mining lunar ice a long time. A google search will find lots of references. Here's one:

http://www.digitalspace.com/projects/sb … index.html

It is not as simple as you might think because the cryogenic cold will destroy many mechanical devices. The alloys must be chosen carefully and tested extensively. The assumptions he is using is that the ice is disseminated in the regolith at a concentration of 1 or 2%. that doesn't sound like much, but it still results in millions of tonnes of the stuff. They are interested in it for fuel as well as hydroponics because fuel really won't consume very much of the water, even in a century of development of a base. There are even studies that Duke was involved in that suggest that lunar ice could be exported to low earth orbit as cheaply as it could be flown up from the earth's surface. You can find them via google.

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#1 2006-08-12 10:24:48

Re: mining lunar ice

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Re: mining lunar ice

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#7 2008-03-06 09:23:23

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#10 2008-04-09 03:55:48

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