A Lunar Colony

spacester · Oct 9, 2005

The glass-making and lots of other stuff is from the excellent work of Geoffrey A. Landis. I sure would like to see somebody build a test factory to validate the very straightforward processes he describes. I couldn't find evidence of such a validation program on the web - but I didn't spend much time at it either. Maybe others here could google it up for us? Structural integrity is the big question. The applicable thermal environment is going to be the prime consideration. IOW if the glass is going to go through temperature cycles as deployed on the surface, it's going to have to be a high quality grade of glass. Happliy, we have what we need to make high quality glass. Except maybe for Boron, so we bring that with us. But the big question for this dome fan is of course that we propose to seal our dome with a continuous layer of glass on every surface, including the floor (except for passages to below, which are numerous). We will be living in a glass bottle. If we want to build the dome to last forever, we want the glass to see little in the way of stress, ever. If we anneal the glass properly, it will be stress-free from the start, so annealing would be assumed, and we need to do it well. We've eliminated the internal stresses, so now it's a matter of eliminating or minimizing applied stresses. Our dome would be buried quite deeply in regolith, so that would provide a lot of thermal insulation. Thus, if the habitat is kept in continuous operation, the temperature cycling would be quite minimal. We are going to pressurize our glass bottle, so if the inner surface of our dome is the glass itself, we will have that structural load. There would also be the load from the weight of the glass in the local gravity field, which is not to be ignored. We've talked about our dome having an inner basalt dome and an outer basalt dome. That was not my original design concept - it was yours, Arobie, IIRC - but now I think it <div class="Discussion_UserSignature"> </div>

kilendrial · Oct 9, 2005

I know this might make you guys angry because you have already decided on solar power, but political considerations aside (launching Uranium in rockets that have been known to explode, or making you guys angry), Nuclear power would be ideal. Although it was said earlier that this debate between power source inhibits the effectiveness of this thread, I disagree. Power source is important for a colony and picking the right one will pay off. If you guys get to into "vision" for space exploration instead of effectiveness in areas, you will most likely end up either killing people or wasting billions. Yes, this project would cost at least a trillion dollars which means that efficiency of .1% more amounts to more than a billion dollars saved. Also, power systems will sustain life, they must work and be the best for the job or people might die. There are 6 factors that I can come up with to take into consideration -power output (how much, continual, reliable) -weight of initial pay-load -volume/space of initial pay-load -time of set-up -what it takes for continual operation (maintenance, supplies from earth, industry on the moon) -special technology development **Power output** Nuclear power works all the time irrespective of solar eclipses, or night-time conditions. You don’t have to build your base at the poles if it is nuclear. You would have to if it was solar. The logistics of polar to base transit of power is too hindering. First, you have to build the wires which takes a lot of work, the energy loss in the form of heat would be considerable depending on the base location, but it would definitely limit your location. If you were to build away from poles, then you would get 2 weeks of night time which would require quite a bit of stored up energy (twice the energy per hour needs to be generated as you only can spend half the time doing it). If you store it in the form of hydrogen and oxygen to be used in fu

bitbanger · Oct 10, 2005

kilendrial, There is a lot that I take issue with in your post, but I'll limit it to a factual error that you base your conclusion on. <blockquote>In reply to:<hr />It takes fuel. Solar panels would take replacement at some point(50 years?) as would the nuclear reactor. For fuel, fission of one 1000 tons of Uranium equals all of U.S. energy consumption. Just send up 1 ton, and you might be able to generate .001 percent of U.S. consumption(41 MW) for a year. For 200 MW, that would mean 5 tons/ year or 500 tons per century. For comparison, the new heavy lift rocket design puts about 125,000 metric tons into orbit. This could send 5 dual 200 MW nuclear submarines and a century worth of fuel for that 2 GW of generation capacity spread over 10 reactors.<hr /></blockquote> The error is that the Shuttle derived HLLV is rated at 100 Metric tons to orbit with an uprated version to 120-125 metric tons. Your figures are high by three orders of magnitude. When it comes to the volume of solar cells, one thing that seems to be ignored by virtually all of the 'nuclear now' proponents is ISRU. I'm assuming that this colony is intended to be economically viable. Unless the local resources are used and sold, all that will result is another 'flags n footprints' mission.

tap_sa · Oct 10, 2005

Another thing that needs clearing up when we are talking about power of nuclear reactors is whether we mean thermal or usable power. I seriously doubt any sub in the world has 400MW of shaft power. And setting up existing naval powerplant on the moon isn't so easy as it sound. You can't just rip it of the sub and whisk it to the moon and except it to run there because there isn't a sea from which suck constant flow of coolant. You'd have to build a radiator, and a very big one if we are talking about hundreds of megawatts of thermal power. I'd still like to hear opinions and guestimates how much kW (electric) per colonist early base would need? That would put some context to the discussion.

spacester · Oct 10, 2005

Hi kilendrial! Welcome to sdc and thanks for joining in! I would like to think that merely stating one's opinion would never 'make us angry'. Sadly, it's not that simple. If you do it the way you just did, there is no reason to expect that sort of 'angry' reaction. But when a person comes in and makes unsupported absolute statements that get in the way of progress, well they are going to get a strong response from me that doesn't dance around the real issue. Those who cannot agree to disagree are not going to have as enjoyable an experience as those who can. I am very comfortable with that approach, and I hope others are as well. Threads are cheap, progress is valuable. I respectfully disagree with much of your post, but almost all of that disagreement is because of the context of this thread. I believe most of that difference can be summed up quickly: We cannot go out and buy a Nuclear Power Plant and launch it. We just can't; that's something our government cannot allow us to do. So the Nuclear Option means it's a Government Program. Well, we are exploring what we, private citizens, can do without much if any direct help from our government. Nuclear would be fabulous. I keep saying that and I mean it. I am not "Anti-Nuclear". (Just because this country is polarized on every issue does not mean we cannot allow our intellects to embrace the concept of accepting the existence of multiple options and make choices from there.) We simply are not willing to jump thru the political hoops required to get Nuclear Power as soon as we want it. We are trying to develop a plan that can be implemented ASAP. This plan is not about what we can do "some day". If we receive $50 Million tomorrow to spend on our lunar space program, we can make a phone call to a solar panel manufacturer and purchase our initial power generation equipment, and begin designing our in-situ manufacturing of more panels to accommodate our event <div class="Discussion_UserSignature"> </div>

kilendrial · Oct 10, 2005

The error is that the Shuttle derived HLLV is rated at 100 Metric tons to orbit with an uprated version to 120-125 metric tons. Your figures are high by three orders of magnitude. Yep, it crossed my mind it seemed a little too high. Now that I look at it closer, that is an aircraft carrier that supports 5,000 crew. I confused 120,000 kilograms with 120,000 metric tons, so yeah - 3 orders of magnitude. When it comes to the volume of solar cells, one thing that seems to be ignored by virtually all of the 'nuclear now' proponents is ISRU. I'm assuming that this colony is intended to be economically viable. Unless the local resources are used and sold, all that will result is another 'flags n footprints' mission. Well, if you are going to be selling your power supply generators, why not just sell nuclear components (basic infrastructure), and while your at it space-ship/colony components or have a chemical industry? I don’t see why metal working and mining for space components wouldn’t have the potential to be just as economical as this solar panel factory. Why not use excessive power from nuclear power to harvest and supply oxygen to space exploration with lower lift requirements from the moon? If you want to make fuel, and you can find water, electrolysis of large amounts of water to make large amounts of fuel would be best suited for lots and lots of power generated by the most potent energy in the universe (mass itself). I think you would be better able to be economically viable if you have the most power possible. Energy supports industry, that turns out products for you to sell/use. What goes into those products could be anything from locally mined Uranium for power to locally mined metals. Another thing that needs clearing up when we are talking about power of nuclear reactors is whether we mean thermal or usable power. I seriously doubt any sub in the world has 400MW of shaft power. Yes, the s

craig42 · Oct 11, 2005

<blockquote>In reply to:<hr />As long as you somehow verify a process to mine and enrich uranium on the moon, you could use nuclear power without much of politics getting in the way <hr /></blockquote> That's definitely the real stumbling block perhaps we can agree that while Nuclear power is the best option technically that solar power is better politically and we'd rather have something faster that's good enough than something better. Of course solar power towers would have better area per kw, and if we wanted to wait for the best power solution, I’d say ship up a few lightweight rectenas and build some SSPS in orbit from lunar materials

nexium · Oct 11, 2005

As built, I suspect, solar power towers produce slightly less kilowatts per square kilometer than top of the line photovoltaic panels. We can instal some photovoltaic panels to catch parts of the sunlight beams that misses the boiler. We can find some otherwise wasted space to put solar troths to preheat the boiler fluid and/or the working fluid. Finding significant quantities of usable Uranium ore on the moon, may take a decade of high level comittment, Can most of the infrrastructure for smelting and enriching, be made from lunar materials in a reasonable time frame? Neil

Swampcat · Oct 11, 2005

"Frankly, when your post begins with a false dichotomy fallacy, then that rather rates your entire post for what it is. Not a logical, factual rejoinder, which actually discusses the problems, but an attack on the person, rather than dealing with the energy problems." [rant]Talk about the pot calling the kettle black. This your usual method of debate. I, for one, would take you more seriously if you stopped all the personal attacks that you seem to enjoy making. OK, I know you are capable of rational discussion. I've even caught you, on a few occassions, admitting to mistakes, in a round about way. You can cut and paste your usual rejoiners in a response to me if you wish. I know it's just your way. I can live with it.[/rant] My question for you, to stay on topic, is how does a private company buy and transport a nuclear reactor to the Moon. I'm not opposed to nuclear power at all. It would be great if it were possible. But I find the prospect of procuring and transporting a nuclear reactor to the Moon by a private group to be a non-starter. I understand all your arguments for nuclear power and tend to agree with them up to a point, but I see no reason why a well thought out plan to use solar power isn't feasible, especially in the early stages. <div class="Discussion_UserSignature"> ------------------------------------------------------------------- "I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."Thomas Jefferson </div>

chriscdc · Oct 11, 2005

There isn't any quartz or silica on on earth pure enough for use in solar cells. Quartz is not used for solar cells or if it is then it is formed as a layer on top of a silicon wafer by oxidising the silicon. The silicon has to be purified anyway in order to grow a crystal from it. I suggest that you read up on semi conductor physics. Lunar regolith has many examples that are rich in silicon eg glass sphericals.

chriscdc · Oct 11, 2005

Silicon used for photovoltaic cells can be of far lower quality than that used for integrated circuits. There are several reasons for this. The silicon does not need to be a single crystal and so lowers the complexity of the manufacture. Far more resistant to regional impurities, whereas in an integrated circuit, small regions (micrometers^3) would ruin an entire chip, whilst a photovoltaic cell will merely suffer a decrease inefficiency. Do you realise how many wafers are thrown out of the manufactoring process of ICs? Solar cells have far larger tolerances and so the manufacturing will be far cheaper. Whilst manifacturing the silicon, the last bits to crystalise out are the impurities. If anything the facts show that silicon is very common on the surface. You just have to be more imaginative at getting it out. Thats just the standard silicon cell. There are various thin films and tandem silicon solar cells. These use far less silicon and so are easier to produce. There are several other forms of solar cell which you could make from the lunar rocks as well. We have another 15 years before we will be manufacturing solar cells on the moon, plenty of time to work out how to extract the silicon. There is a quiet revolution occuring in the world of catalysts, thanks to quantum dots, wells and carbon nanotubes. Labs on a chips, provide massive surface areas for reactions to take place. So why waste uranium when it could be used for deep space missions and other times were you cannot have thousands of km^2 of solar panels.

Swampcat · Oct 11, 2005

Thank you for your response. "Yours is just a false barrier to a reactor being sent up..Regarding your other comments, typical for around here, the 'tu quoque' is egregious, but typical. " It wasn't intended to be a false barrier as I have no problem with sending up a reactor or using nuclear power. It was a serious and pertinent question. I admit my other comments are rather typical for responses to your posts, but IMO you reap what you sow. " It's not the reactor which one needs the license for. It's the nuclear materials. Most utilities and many other private orgs can get access to them if they are competent to handle them." I must admit that I should have said materials rather than reactor. Mea culpa. (Had to use some Latin for you <img src="/images/icons/smile.gif" />). So what kind of expertise is required, how many people needed and what kind of red tape does it take to procure nuclear materials and transport them to the Moon and operate a nuclear reactor? Consider that solar is a fairly low tech solution without the need for permission from the government to use, requires less expertise to set up and operate and has a proven track record in space. " There is a difference between honestly criticising a person's statements, versus calling them names." Quite true. Please take it to heart. I'm trying to develop my own opinion on this issue. I respect your intellect and your knowledge. Really, I do. But I don't respect your posting style. <div class="Discussion_UserSignature"> ------------------------------------------------------------------- "I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."Thomas Jefferson </div>

spacester · Oct 11, 2005

Reviewing previously posted material . . . Silicon Dioxide is a poor choice of feedstocks for glass anyway - it is not readily available but more importantly the operating temperature is 1710 C. Happily, and not just theoretically, a combination of silicates of Calcium, Magnesium and Silicon make quite good glass. The bonus: the operating temperature is much lower: 1130 C It has been verified in the lab with lunar regolith analog. The theory is not exactly a stretch, humans have been making glass for quite a while now. The process for extracting Silicon is rather straightforward - I didn't say 'easy' - and the product is 100% pure. <div class="Discussion_UserSignature"> </div>

nexium · Oct 11, 2005

My guess is pure silcon for solar cells can be obtained from regolith at 42% silicon dioxide, on the moon at less than double the cost of obtaining it from highest quality quartz, even if 100 extra purification steps are required, excluding engineering costs to learn how to do that. An average of 100 watts per square meter at high elevations at the poles of the Moon may make 1000 megawatts available. Suppose we have 20 sites averaging 1/2 square kilometer = 10 million square meters. The sites are inter conected by a pair of wide spaced wires totalling 100 kilometers. The cells are connected in series parallel to produce 5 million volts DC between the wires. The current is 200 amps if all the energy is put on the grid. Some of the energy can be used close to and under each solar aray, so average current may be 50 amps Admittedly reducing the 5 million volts for mundane uses will be challanging, but several DC power lines of almost a million volts are under construction. Does anyone know how low voltages will be obtained from these power grids here on Earth? Neil

chriscdc · Oct 11, 2005

Excellent. Can the process be continuous or is it batch only?

bitbanger · Oct 11, 2005

You didn't provide the complete quote, nor was your response in context to my comment. The actual quote was: <blockquote>In reply to:<hr />The error is that the Shuttle derived HLLV is rated at 100 Metric tons to orbit with an uprated version to 120-125 metric tons. Your figures are high by three orders of magnitude. <hr /></blockquote> I was correcting a factual error on the HLLV launch capacity, which implied several functional reactors could be launched and delivered complete to the Moons surface. Since you have now suggested that the reactor will need to be built in place, I ask again where is the power going to come from to support the construction workers until the reactor is built? I suspect that the initial power supply for any Lunar base will be probably be a hydrogen fuel cell being recharged by solar. To clarify though. I do think that either a fission reactor, or hopefully a fusion reactor would be the ideal long term power source for any Lunar base. I just don't believe that the first power source shipped up (or built in place) will be a nuke.

barrykirk · Oct 12, 2005

There are two alternatives being discussed here. 1. Solar Photovoltaic. 2. Nuke. What about Solar Thermal? That shouldn't require pure silicon to run.

craig42 · Oct 12, 2005

<blockquote>In reply to:<hr />The facts are if the energy cost to make solar cells is too high, as it likely would be using very impure Si sources, the solar panels would use up more energy in manufacture, than they would return in power output.<hr /></blockquote> The if there being the key operand <blockquote>In reply to:<hr /> Guessing does not mak eit here (sic). Putative 'the means exist' doesn't either. It's going to take refining Si from moon rocks, that is, lunar surface R&D to prove that. And NO one, I repeat, No one is going to depend on something which is not substantiated and proven for energy. <hr /></blockquote> Come again? If we weren’t going to depend on unproven technologies, we’d never have gone to the moon in 1969 since it hadn’t been done before. The claim that <blockquote>In reply to:<hr /> Guessing does not mak eit (sic) here<hr /></blockquote> and a guess that <blockquote>In reply to:<hr />it likely would be using very impure Si sources<hr /></blockquote> seems to be a contradiction to me, or am I missing something? The fact is until we get numbers (either via carfully calculated theortical maths or even better lunar r&d) we don't know if the energy costs of lunar made solar cells are greater than thier lifetime production or not. <blockquote>In reply to:<hr />Big problem, that lack of any large amounts of quartz on the moon.<hr /></blockquote> Agreed, this is certainly the biggest technical challenge for solar. Of course one could argue as to where exactly the Uranium/Plutonium deposits are? <blockquote>In reply to:<hr />But then one'd have to consider what was the power source of the first lunar lander? Way back in 1969? <hr /></blockquote> According to Wikipedia [url =http://en.w

scottb50 · Oct 12, 2005

What about Solar Thermal?>>> I would think the complexity would be pretty high. You would need a working fluid, a containment system and a means of generating power from the thermal energy as well as a means of cooling the fluid so it can be re-used. I would think it would take some pretty big radiators just like Nuclear would need. I've been in the abandoned cooling tower in Washington, were the plant was mothballed before the reactors were installed, they are huge and give you some idea of the heat that needs to be removed. This is transfering the heat to the air, something a lot easier to do than radiating it into Space. <div class="Discussion_UserSignature"> </div>

barrykirk · Oct 12, 2005

Well, if the cooling problem is a problem for solar thermal, it will be the same cooling problem for nuke power. I just pointed towards solar thermal, because it rides between the problems of nuke and solar photovoltaic. For the reflectors, aluminum should be easier to obtain from the lunar materials than silicon for the PV panels. Standard cooling towers obviously won't work on the moon. The only cooling methods available on the moon are conduction and radiation. Both are going to be difficult.

scottb50 · Oct 12, 2005

Of the three solar panels still make the most sense. I would expect it to be a long time before enough power is available to build solar cells on the moon, but the solars cells brought from Earth could be spread out once an operable number are in place it would just be a matter of plugging in new ones as power needs increase. Compared to the amount of mass that would be required for thermal and Nuclear it would be more efficient. <div class="Discussion_UserSignature"> </div>

spacester · Oct 12, 2005

Quartz is not needed. There are other sources of Silicon. There are other feedstocks for glassmaking. The lack of quartz is a complete non-issue. Don't take my word for it. Click the links, read the paper. Geoffrey Landis is not a quack. http://www.asi.org/adb/02/13/02/silicon-production.html http://www.asi.org/adb/02/13/01/glass-production.html <div class="Discussion_UserSignature"> </div>

chriscdc · Oct 12, 2005

Shame you missed the point. I was pointing out the large disparity between the silicon used for ICs and for photovoltaics. The hardest part of the purification getting it from 99.99% to the 99.9999% or so percent purity for ICs. This is why solar panels are several orders of magnitude cheaper than even a blank silicon wafer (for the same volume). Economics 101 for you, cost is largely dependent upon the effort required to produce the product. The process to remove the last few impurities is enormous compared to any other step in silicon processing, apart from shipping, but on the moon it would be easier to move the factory. For someone who seems so sure of himself you use the word if rather often. Being imaginative is what has gotten us to the current state of integrated circuits. There are probably many ways of removing the silicon from the rocks. The reason that you haven't heard of them is that on earth companies normally use the most efficient process. Also on earth they want to produce hundreds of kilos per day, whilst the moon manufacturing could get on with only a kilo or so. As I said on the catalyst point, we are discovering far more about how large groups of atoms and their electrons behave. This knowledge is going into multiple areas such as testing alloys on the computer without having to make large amounts for testing. The largest area though that this research is going into, is the manufacture of catalysts. The fact that we can make tons of fairly uniform nanotubes per day is because of this very research. By 2020 it will be likely that you could catalyse almost any reaction that you want. So Lunar R&D is required, big deal, we will have many sample return missions for scientists to test out methods. Then you build a rover/mobile factory and test out your plan. A solar powered rover could easily produce sqr meters of solar panels every day. At the end of the panels liftime you can use an even simpl

spacester · Oct 12, 2005

My understanding is that solar thermal is assumed as our source of process heat. We have also mentioned using a sterling cycle turbine to generate electricity from a large temperature difference, but have not gone into any detail there. But process heat is where solar really shines. (har har) Specifically, in the case of producing pure silicone from the regolith, we would use a solar furnace to heat the crucible containing the eutectic salt mixture (potassium fluoride, sodium fluoride, calcium fluoride) in which we electrolyze the potassium fluoride at 676 C to obtain our reactants. This step requires the most electrical power by far. The fluorine is passed to the regolith furnace, which needs to operate at 500 C, but needs no electrical power. From this we obtain SiF4, Oxygen and metal fluorides. We then cool the gases to separate the SiF4 from the Oxygen by condensation at 178 K (-95 C) Next the SiF4 is reacted in plasma to form silicone. This is the most speculative step of the process (at the time Landis wrote the referenced paper), simply because existing processes use Silane (SiH4) but we propose to use SiF4. Landis assumes we can produce "silicon of acceptable quality", so it must be noted that we need to verify that process here on Earth before we go much further. Not that failure is expected or that the whole thing is moot if it does – it just becomes more difficult to get the silicone, we need multiple steps instead of this easy one. We would have to replace the F with H at high temperature and pressure, then use our common industrial process to get the silicone out. So we got want we wanted – pure silicone – and oxygen too, though with a lower O2 yield than ilmenite reduction ("standard LUNOX process"). But we need to get our potassium fluoride back to recycle back to the crucible. We get some of the Fluoride back when we separate the silicone, but much of it is tied up in fluoride salts (metals plus fluorine). <div class="Discussion_UserSignature"> </div>

j05h · Oct 12, 2005

What about using RTGs for baseline power and solar for manufacturing? RTGs don't produce as much power as a critical reactor but are less politically controversial. Eh, when the need arises for space nuclear power, it will be available. There are plenty of commercial providers and the Navy is brimming with small-reactor experience. Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

A Lunar Colony

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