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#51 2005-10-26 10:13:33

Grypd
Member
From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

Re: Lunar Carbon?

Biospheres Extranational will do business with Terran associates who have been appropriately certified.  We will, of course, require that our Terran associates comply with their ambient legal environment.

So where will Biospheres international be based where is its home address, where do we send the bills

For the companies that matter to be able to sell you anything you must give that registery number to them and also be in a situation where they are allowed to sell to you.

"Companies that matter" will rapidly become "companies that used to matter" if they are unable to participate in the extraordinary opportunities being pursued by Biospheres Extranational and its competitors.  Of course, "companies that matter" don't need to be told this.  Did you know that Boeing Russia ( http://www.boeing.ru/ ) has over 10000 employees?

Boeing Russia is a subdivision of Boeing international an american company. In Russia it must obey all local laws but it also cannot sell from Boeing Russia what Boeing USA has developed that the USA considers high tech or militarily valuable without the appropiate United states licence. In short one company but two hands. And since all launching eguipment and a lot of material used in space is high tech and potentially military grade it often falls under needing licences. Developing a shell company as it is called is fine but that shell company in international law is considered the same nationality as that of the parent company.

The outer space treaty is the reason these companies will not so invest

I disagree.  The commercialization of the internet was fiercely contested.  In the end it stopped no one.  However, it did enable bold first-movers to eat the lunch of the dinosaurs.  The tipping point was the advent of enabling technologies.

The commercialisation of the internet in fact the internet in general is not useful as a symbol of what would happen in space. The internet is an example of the latest type of property that of intelectual property rights. The internet is a case where the thing appeared and the legal system had to play catch up. The Moon and the space in general though is a case of physical property and there is already a very negative law enforcing  what is allowed and not allowed in space. Enabling technologies for Lunar development would be great but as noted who would pay to devlop such when they may or not be allowed to use that technology to make profit. In essence if you develop an effective TSTO spaceplane but can only sell a couple to the goverment then you cannot make enough of a profit if any to pay for the development of such a TSTO spaceplane. That is the situation the outer space treaty imposes on us. With a decent section on allowing use of and claims to property on the Moon etc then companies will be very interested in that TSTO spaceplane and you can sell more. Sell more and prices come down not only of the spaceplane but actual costs to get to space.

activist pressure groups.

are invited to register for exclusion from the benefits of space commercialization.  We'll do our best to comply with their wishes, although it may be difficult because the benefits will be so extensive.
.

Do not simply ignore pressure groups they can have voices in the wrong ears. The law of the Sea is an example where small third world goverments and activists have in effect stopped commercialisation of the sea bed and stymied the western world. These small countries will want a share of the pie without paying for the risk. Currently if you start mining PGMs and transport them to Earth you are more or less quaranteed to end up in court as smaller countries and activists try to force you to hand over there rightful "share" of what is the whole worlds property.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#52 2005-10-26 10:43:07

SpaceNut
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Re: Lunar Carbon?

off topic

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#53 2005-10-26 11:10:08

Grypd
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From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

Re: Lunar Carbon?

Which sort of puts the UN in the drives seat to start funding off this world (moon, Mars and beyound) and not just LEO missions from any space fairing capable nation. It should as well be setting up a global disaster network of satelites for all nations. But how would they fund such things?

This is the UN that systematically failed the people of Darfur and Iraq, that has shown its Oil for food programme to be an example of corruption from the highest office to the lowest. The UN is an example of a rampant Bureaucracy, The good it does do is often more expensive than is necassary due to its very high overheads. The WHO a UN affiliate is an example where for every doctor or nurse in the field there is a paper pusher behind them. Would I trust the EU to do what is necassary to develop space if it somehow gained a means to do so. Of course not.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#54 2005-10-26 12:11:08

noosfractal
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From: Biosphere 1
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Posts: 824
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Re: Lunar Carbon?

So where will Biospheres international be based where is its home address, where do we send the bills

Like any large business entity, Biospheres will contract with accounting service providers at multiple Terran locations.  New York, Moscow, Shanghai, Bangalore, Anguilla - please choose the service center that best suits your needs.

it also cannot sell from Boeing Russia what Boeing USA has developed that the USA considers high tech or militarily valuable without the appropiate United states licence.

Pretending, for the sake of argument, that US export controls are actually effective at preventing the transfer of some important technologies, you're right, Boeing Russia must contract with Definitely-Not-Boeing Research and Development Company next door to develop a substitute.  Because it has already been done and DNB employs PhDs graduated from US universities, the substitute is usually fine, sometimes good and, every now and then, better.  No matter what, it is definitely cheaper.

The internet is a case where the thing appeared and the legal system had to play catch up. The Moon and the space in general though is a case of physical property and there is already a very negative law enforcing  what is allowed and not allowed in space.

The parallels are not exact, of course, but there are parallels.  The treaties are full of deliberate loopholes.  They prevent nothing during the research and development phase, and by the time profits were being generated their only effect will be to require addition of the phrase "we come in peace for all humankind" to the corporate mission statement.  International law is nowhere near as settled as you seem to believe.  Extranational law is ours for the shaping.  It's a frontier.  That's why it's fun, right?

Currently if you start mining PGMs and transport them to Earth you are more or less quaranteed to end up in court as smaller countries and activists try to force you to hand over there rightful "share" of what is the whole worlds property.

Cost of doing business.  I'll hire the same attorneys and negotiators used by the oil companies.
.


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#55 2005-10-26 14:16:25

SpaceNut
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Re: Lunar Carbon?

off topic

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#56 2005-10-26 14:24:54

Grypd
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From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

Re: Lunar Carbon?

So where will Biospheres international be based where is its home address, where do we send the bills

Like any large business entity, Biospheres will contract with accounting service providers at multiple Terran locations.  New York, Moscow, Shanghai, Bangalore, Anguilla - please choose the service center that best suits your needs.

And get taxed by all of them. A true extranational will need to be able to have its own infrastructure completely independent of a country. People have considered using the internet as a posibility to be a viable means to create such an entity. But as greenpeace have discovered this is not an option that is either legal or would actually be taken seriously. Ever heard of sealand?

it also cannot sell from Boeing Russia what Boeing USA has developed that the USA considers high tech or militarily valuable without the appropiate United states licence.

Pretending, for the sake of argument, that US export controls are actually effective at preventing the transfer of some important technologies, you're right, Boeing Russia must contract with Definitely-Not-Boeing Research and Development Company next door to develop a substitute.  Because it has already been done and DNB employs PhDs graduated from US universities, the substitute is usually fine, sometimes good and, every now and then, better.  No matter what, it is definitely cheaper.

Yes but as noted to get into space will need a lot of ground based infrastructure and a lot of money. To purchase this you need a base and a means of credit flow. You also will have to be able to bargain with these large companies.

The internet is a case where the thing appeared and the legal system had to play catch up. The Moon and the space in general though is a case of physical property and there is already a very negative law enforcing  what is allowed and not allowed in space.

The parallels are not exact, of course, but there are parallels.  The treaties are full of deliberate loopholes.  They prevent nothing during the research and development phase, and by the time profits were being generated their only effect will be to require addition of the phrase "we come in peace for all humankind" to the corporate mission statement.  International law is nowhere near as settled as you seem to believe.  Extranational law is ours for the shaping.  It's a frontier.  That's why it's fun, right?

Unfortunatly the one thing international law has a lot of is property legislation. It is this that is only second to religion that has started wars. Look at the possibilities that are forming from the melting of the Artic. In the 19th century there would have been a major landrush to gain these new resources but they are taking it to arbitration though they are using the Law of the Sea even if the USA is not a signatory. This is actualy forming what could be described as a point of law, and this point of law and with the similarity of the outer space treaty and Moon treaty with the law of the sea is likely to mean that such will be used against lunar exploitation.

Now if we only could have a case where there becomes a base which is not subject to the Moon or Outer space treaty. Of course that requires that a country that has the capability to get to the Moon and exploit it actually also not be a member of any current treaties. About as likely to happen as finding "unobtanium" in the next week. Our best hope is that we can put pressure on the goverments of the ESA group and USA and Canada to get the Moon Treaty dropped and the Outer space treaty revised.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#57 2005-10-26 16:07:47

John Creighton
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Re: Lunar Carbon?

I wish people would stay on topic. You can always start a new thread if you want to discuss space law.


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#58 2005-10-26 19:05:42

SpaceNut
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Re: Lunar Carbon?

edit off topic:

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#59 2005-10-26 20:54:10

noosfractal
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From: Biosphere 1
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Re: Lunar Carbon?

I wish people would stay on topic. You can always start a new thread if you want to discuss space law.

Sorry about the digression John, I'll focus on the scenario in which Biospheric Power Generation (a wholly owned subsidiary of Biospheres Extranational) is selling kWhs and we can discuss exactly how their customers will be classified into "scientific" and "non-scientific" in another thread  roll

I was looking into CVD processes for thin-film solar cell manufacture, and the actual process for building the solar cells seems straight forward enough - you just lay a half dozen layers one on top of the other.  CVD concerns include deposition rate (how thin can the layers be?), keeping the chamber walls clean (otherwise bits can drop on to your otherwise pristine solar cells), keeping the deposition nozzles unclogged, and withstanding medium and long term erosion by evil gases like fluorine.

However, these things seem to be doable.  What concerns me a little more is automated manufacture of a substrate and deposition gases of sufficient purity from luna regolith - all on the same rovot.  I assume we can choose an easy area, but there is still going to be some inconveniently large rocks about – so maybe some sort of dozer-sieve to begin with, and we won’t be able to always go in straight lines, and we’ll have to be able to cope with stop and go – hopefully we can avoid sharp shocks to the deposition chamber.  Then there is the fact that we’ll only want a relatively small amount of the material we dig up, so there is going to be a mound of dirt to one side. 

Then we start to get to the separation processes.  Spraying fluorine gas at the regolith gets you SiF4 – which can probably be used as a deposition gas (leaves behind the silicon, recycle the fluorine) - but it probably gets you other stuff as well, some of which you are happy about because you want to use them as dopants, but the whole point is to keep the different dopants separate.  The different gases might form separable layers at different temperatures and pressures – but you are going to have to be careful that you don’t waste too much fluorine each time ‘cause it’s about as common as carbon (i.e., you’re going to have to ship it from Earth). 

Here is a paper by Landis on silicon production that talks more about fluorine ...
http://www.asi.org/adb/02/13/02/silicon-production.html

I’m wondering if you wouldn’t have at least two types of rovot: raw materials refiner and solar cell paver.  The pavers could visit the refiners when they got low on something.
.


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#60 2005-10-26 21:01:36

John Creighton
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Posts: 2,401
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Re: Lunar Carbon?

There is another problem. It is not enough to make the solar cells but you also need to build the rest of the power system, which includes diodes and other circuitry to by pass solar cells that are damaged or temporarily shaded. I’m not saying it won’t work it just some how sounds to me too good to be true. We should try it but for some reason I am slightly skeptical.


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#61 2005-10-26 21:27:03

noosfractal
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From: Biosphere 1
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Re: Lunar Carbon?

There is another problem. It is not enough to make the solar cells but you also need to build the rest of the power system, which includes diodes and other circuitry to by pass solar cells that are damaged or temporarily shaded.

I'm imagining really simple wiring - basically a positive and a negative aluminum rail.  Damage to a particular cell should just lower the current unless there is a major cut.

You might want some sort of power storage system - maybe a superconducting coil in some nearby lunar shade.

I’m not saying it won’t work it just some how sounds to me too good to be true. We should try it but for some reason I am slightly skeptical.

You're right to be skeptical.  Factory floor automation - where you have an army of human attendants - is one thing.  Total automation is another level.  I think we can do it.  The question is whether the cost/kg will justify it.  If we can just roll-up 20 MWs worth of thin-film solar cells into a 2 ton payload and unroll it on the lunar surface, then the expense of high automation is probably not justified - for lunar purposes anyway.  At the $2m/kg price point for Mars, a whole lot of automation is justified  smile
.


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#62 2005-10-27 06:51:02

SpaceNut
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Re: Lunar Carbon?

Yup John is correct for each solar panel or grouping of cells will produce a certain amount of power but this comes at a sacrifice of the output of the cells voltage varying with the amount of solar energy absorbtion and then there is the load factor to which as it increases the avaiable voltage output for a direct connection will cause it to droup as well.
This facilitates the need for an invertor stage for battery storage to smoothen out what is available from the solar panels to meet the demand at the time of use which can be greater than what the power level is from the panels.

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#63 2005-10-27 15:30:41

Grypd
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From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

Re: Lunar Carbon?

Sorry John for that digress to space politics but back to the topic.

There is an alternative to attempting to make photovoltaics cells with silicon or gallium arsenide, the standard types we currently use. The problem with the silicon cells are that the various types all require a degree of "doping" and this doping is always of a material that is rare on Earth and likely to be almost non existent on the Moon. Gallium arsenide is a very rare element off the planet Earth.

We could create solar cells out of the Ilmenite that is current on the Moon. The Ilmenite will with the Moon being a reducing enviroment will be up to 20% by volume of the lunar regolith. It has a doping element but this is actually Iron oxide and we know this exists in quantity on the Moon as well. There is a problem with this cell in that it has only an efficiency of between 15 to 19%. It has one great advantage though in that it is extremely radiation hard unlike the Galium and silicon types.

Still if we want to be sure of a good constant flow of electricity then we must ensure that the cells are made larger than normal. Up to 40% bigger in size if we are to be realistic for silicon and galium based cells but ilmenite is naturally tough so we can get away with normal size but we will still make them larger to ensure a long life.

One other point is that I have noticed that Robots and the various plans designed to create solar cells often leave them as what I can only call paving. This is nonsensical and actually wastes the cells as Lunar regolith is not even. Add to this that it also wastes area and produces more current loss and with lunar dust it also allows for them to be occluded too easily. The best way to get cells is to put them on an A frame and though the rear side cells stay dark for 50% of the time it also allows an increase in area and for the use of superconductors to transport the electricity. The A Frame will shield the sun from the superconducting power wire and with dark areas being up to -233 degrees then we can get them to work and what one cell produces can be made available all across the power grid.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#64 2005-10-27 19:26:08

SpaceNut
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From: New Hampshire
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Re: Lunar Carbon?

I had remembered that a few years back something about a 3 junction cell format.
Here are the links:

http://www.space.com/businesstechnology … 00713.html

http://www.spacedaily.com/news/solarcell-99a.html

http://www.spacedaily.com/news/solarcell-03a.html

http://www.spacedaily.com/news/solarcell-03c.html

http://www.spectrolab.com/

http://www.nrel.gov/solar/

The company claims to have a process for 39 % effiency. One of the links talks about cell degrade while the last one is the National laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy.

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#65 2005-10-28 01:14:51

Rxke
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From: Belgium
Registered: 2003-11-03
Posts: 3,669

Re: Lunar Carbon?

Since solar celss are made out of the same material as IC's, wouldn't it be relatively easy to etch the needed electronics on the cells/wafers themselves, using the currently well established lithographic techniques used in chips manufacturing? Of course, there would still be the challenge of cabling...

Grypd:

I have noticed that Robots and the various plans designed to create solar cells often leave them as what I can only call paving. This is nonsensical and actually wastes the cells as Lunar regolith is not even. Add to this that it also wastes area and produces more current loss and with lunar dust it also allows for them to be occluded too easily. The best way to get cells is to put them on an A frame ....

Disagree. Robotical deployment will prove hard even for basic 'pavement' cells, so stick to that, at least initially.
The engineering, deployment, maintenance,... costs to make robots that build frames etc will probably be much higher in the short term  than sticking to the 'pavement' approach. Once you have your pavementbot (TM), you could start selling power to users, then use that money to invest in more elaborate designs. Also, I'm betting horizontal or slanted tiles will get dusty at about the same rate, low gravity and stickyness of the Lunar dirt in mind...

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#66 2005-10-28 06:58:36

SpaceNut
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Re: Lunar Carbon?

quotes from Spectrolab

Products - Space - Cells

Spectrolab produces active, radiation-hard solar cell junctions using diffusion or epitaxial growth methods. We optimize our manufacturing capability by using statistical process controls to maintain and further expand our Six Sigma quality performance.

As Ryke noted:

We apply the latest photolithography and vacuum deposition tools to meet tough metallurgical and stochiometric compositions for long-life contact collection and stable optical coatings. These technologies allow us to optimize performance in extreme assembly and space environments.

As well as custom improvement for location of use:

We employ state-of-the-art laser and diamond wheel cutting techniques to define solar cell sizes that meet customer-specific applications. Our experts select the best materials for use in assembling solar cells into circuits, which are designed for low earth, geostationary, or deep space missions. Coverglass protects solar cells from the impact of micrometeorites and help to meet the demands of radiation and thermal environments.


A noted in the 3 junction product:

Product Description
Substrate Germanium
Solar Cell Structure GaInP2/GaAs/Ge
Method of GaAs Growth   Metal Organic Vapor Phase Epitaxy
Device Design Monolithic, two terminal triple junction.   n/p GaInP2, GaAs, and Ge solar cells interconnected with two tunnel junctions

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#67 2005-10-28 11:34:53

Grypd
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From: Scotland, Europe
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Posts: 1,879

Re: Lunar Carbon?

Disagree. Robotical deployment will prove hard even for basic 'pavement' cells, so stick to that, at least initially.
The engineering, deployment, maintenance,... costs to make robots that build frames etc will probably be much higher in the short term  than sticking to the 'pavement' approach. Once you have your pavementbot (TM), you could start selling power to users, then use that money to invest in more elaborate designs. Also, I'm betting horizontal or slanted tiles will get dusty at about the same rate, low gravity and stickyness of the Lunar dirt in mind...

Solar cell manufacturing plants will be heavy and power hungry. Making them mobile though a useful idea is dependant on that plant being able to recieve power and a supply of materials to make cells with. Fundamentally the plant should be in a fixed position and attached to its own fixed power supply and materials brought to it. The finished solar cells will then be taken by telerobotic means to where they are to be emplaced and then connected to the growing power net. We can already make A Frames from Lunar material and attaching cells to it should not be too much of a problem.

Putting solar cells on A Frames allows for there cleaning to be done a lot easier than simply having them layed in pavements on the ground. It improves there time in the sun and also Thermal properties can be kept reasonably constant.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#68 2005-10-28 12:02:54

Rxke
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Re: Lunar Carbon?

We can already make A Frames from Lunar material and attaching cells to it should not be too much of a problem. .

Can we? I mean, all of this discussion is nice and dandy, but AFAIK the only paper re: solar cell manufacturing in-situ 'proved' it was theoretically possible, because the needed materials are there. No plans re: hardware whatsoever exist.

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#69 2005-10-28 13:17:56

SpaceNut
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Re: Lunar Carbon?

Here is a document that details out the mining equipment. process of getting to location and the seperating into components for reuse. Thou is not totally geared at solar cell manufacturing it is a starting point for desings around simular issues.

The particular seperation is for getting water from Ilmenite (FeTIO 3 ) by bring H2 from earth to use as a reducer along with 1,000 degrees Celsius of heat. They go into the fisability of heating from microwaves I think. Have just only scimmed though this document briefly.

Just goes to show that much of the work is out there.

[url=http://www.fsri.org/Grant%20Process%20Chart/Purdue%20ISRU%20Design.pdf]Purdue Advanced Lunar Apparatus, Maximizing Excavation
and Delivery of Experimental Sciences
Purdue University[/url]

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#70 2005-10-28 13:40:59

Grypd
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From: Scotland, Europe
Registered: 2004-06-07
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Re: Lunar Carbon?

We can already make A Frames from Lunar material and attaching cells to it should not be too much of a problem. .

Can we? I mean, all of this discussion is nice and dandy, but AFAIK the only paper re: solar cell manufacturing in-situ 'proved' it was theoretically possible, because the needed materials are there. No plans re: hardware whatsoever exist.

Yes we do theoretically know the best way of doing a lot of things but our actual knowledge on the best way to operate takes an actual prescence. And we need a lot more knowledge of the actual materials and there properties than we currently have. A decent geological survey would be nice you know. Actually a decent map of the whole moon with an accuracy of better than + or - 100km would be even better. Incidentally this is all stuff that will give us help for future Mars missions too


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#71 2005-10-28 13:56:59

Rxke
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Re: Lunar Carbon?

our actual knowledge on the best way to operate takes an actual prescence. And we need a lot more knowledge of the actual materials and there properties than we currently have.


Disclaimer: I'm not attacking *your* point, to be clear, it's just that I feel increasingly errr... underwhelmed by the state of our engineering knowledge... Or plans.

I meant: we have samples, so we could mix up a big load of simulate 'Luna-soil.' Saying we've got to get there first to be 201% certain of what we will find is putting the real challenges on the backburner by another decade We can test lotsa things here.

If we (by which I mean: NASA, ESA, tSpace, Mars Society, and wel... everyone...) are serious about this, we should build proof of concepts NOW, Hattammit.

Or at the very least set up conferences with universities qnd pooling knowledge, break apart the pieces of the puzzle, try to fit them, integrate those pieces in Doctorate programs etc.

In this day and age that is ridiculously easy. Be it governmental or private, to get this started, just assemble a small team of broadly educated peeps with a broadband connection, and start organising meetings.

Until that happens, I'm not at all impressed with the new Initiative, there are no long term plans beyond 'uh, and then we land... And take off seven days later.'

And yes, before one of you asks, I have a headache, grumble grumble, spit, hiss. wink

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#72 2005-10-28 14:07:21

Grypd
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From: Scotland, Europe
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Re: Lunar Carbon?

Its alright Rxke I do understand.

We unfortunatly do only have theoretical experience of Moon engineering and a lot of our practice and skills comes from making what is in effect artificial lunar soil. We do though have experience of making beams in space it was one of the shuttle experiments early on and it worked well. Making the components for that machine needs mining and smelting. It is possible to make it of artificial lunar glass from the abundance of silicon but again that is theoretical.

Lunar science and engineering is a science that will I hope take off especially now that there will be a return to stay. Along with the now flourishing science of Robotics.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#73 2005-10-28 17:53:41

J.J. Moesker
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From: The Netherlands
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Posts: 19

Re: Lunar Carbon?

Now, this solar cell production thing isn’t really my cup of tea but I do remember seeing a paper called “First demonstration of photovoltaic diodes on lunar regolith-based substrate” published in Acta Astronautica recently. I have only skipped trough the abstract and summary so don't ask for details. Yet there certainly is practical work being performed in this field. I belief the paper was written by researchers from the university of Houston. They demonstrated the first photovoltaic ‘diodes’ fabricated on lunar regolithsubstrates using techniques that could be used on the moon.


With both feet on the ground you won't get far.

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#74 2005-10-28 19:37:23

noosfractal
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Re: Lunar Carbon?

“First demonstration of photovoltaic diodes on lunar regolith-based substrate” published in Acta Astronautica recently.

Thanks!  Full ref ...

Acta Astronautica, Volume 56, Issue 5, Pages 537-545 (March 2005)
C. Horton, C. Gramajo, A. Alemu, L. Williams, A. Ignatiev and A. Freundlich
Texas Center for Superconductivity and Advanced Materials

Schematic ...

  • Horton_schematic.jpg

As with the other paper earlier in the thread, you just melt the luna regolith to make a glass substrate.  Melted, it looks like this ...

  • Horton_luna_glass.jpg

Summarizing ...

You don't use plasma deposition, you take advantage of the ambient vacuum and use thermal evaporation directly onto the glass substrate you just made. 

Don't try to refine the dopants out of the regolith, just bring them from earth.  You only need between 1-10 ppm (i.e., for every million kgs of Si, you need betwen 1 and 10 kgs of dopant).  Don't pre-mix the dopants, just "co-evaporate" them.

Alternatively, bring pre-doped Si from Earth - just for the thin-film part of the cells (blue in the diagram).  For a 5 µm film with 10% efficiency, 30-60 kg gets you 250 kW (i.e., 4-8 kW/kg).  2 µm film with 10% efficiency may be possible.

If we go that route, perhaps cadmium sulfide/cadmium telluride (CdS/CdTe) is better.  Lower evaporation temperature (900 K vs. 1700 K), delivers 10-15% without hyperfine adjustment.

One of the big weight savings is in elimination of support structures required to survive launch.
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#75 2005-10-28 21:06:31

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,314

Re: Lunar Carbon?

The top and bottom busbar electrodes could be made from regolith as well.

The electrolysis of anorthite, 2 CaSi 2 Al 8 O which is modeled after
conventional industrial aluminum production, would be a viable option except that anorthite is available in the lunar highland soil.

Granted gold or copper would be better but you do with what you can find...

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