Justify Moon Exploration with Lunar Power Stations

[rjoshb]

Hi all, since this is my first post here I'll try not sticking my foot into my mouth. Today, I read that the top Democrat on the Senate committee responsible for NASA's budget said the NASA budget was in for a hard time.<br />He also suggested suppliers, and contractors lobby their congressmen. <br />That said NASA is going to have to come up with some way to sugar coat the budget and make it more palatable to Congress and the public. So.. here is my pitch. The moon is made up of mostly silica and has abundant year round sunshine. Why shouldn't the first goal of the exploration be to set up power stations on the moon. The resourses are there, including the metals that go into the voltaic cells. You could even set up a solar furnace to melt down the components. The system could be remotely operated once it was constructed. The big issue as I see it would be to transport all that energy to the Earth. Perhaps some sort of battery might do the trick, or transmission stations in orbit. A really wild idea would have the energy collected on the moon, relayed to reciever satellites in high orbit, or at L-5, and then transmit the power to a space elevator that runs the energy down to the surface. Something to think about isn't it.

 

[nexium]

Few if any spots on the Moon have year round sunshine. The few that have sunlight 90% of the time (at the poles) have a slowly changing sun angle, so stearable solar panels are needed unless 65% of the solar panels producing no electricity is satisfactory. I agree the moon has abundent silica, but separating high purity silicon from the silica on the moon may not be practical this decade or next. Most of the other materials needed to collect and transmit solar energy also require extensive infrastructure, which may be impractical on the moon for decades. Neil

 

[chriscdc]

The main method proposed would be to use microwaves. Microwaves can be absorbed and turned into electricty using a microwave rectenna which is an efficient method of transmitting energy.<br /><br />We've been having this discussion on the lunar base proposal. The main problem is how to get the silicon from the regolith. IIRC silicon dioxide accounts for around 40% of the crust, but its not in nice easy chunks to pick up. In other words you need a process that can identify and isolate individual grains of reasonable purity. What I suggest is similar to how they identify debris and remove it from nut kernels. You drop the material over an edge so it forms a thin falling 'film'. You then use an optical method to identify the particles you want. To remove them from the stream you could use a particle stream, or UV source to ionise that specific grain and then use an electric or magnetic field to remove them. <br /><br />To purify the remaining quartz, we normally use chemicals but that is going to be expensive to ship them up there, and difficult to recycle them. I therefore suggest we try a 'brute force' approach. Heat up the material and bombard it with photons or electrons that have enough energy to break the Si-O bonds. Heating up the material with a solar concentrator. You can use previously built solar panels, to provide the energy for the higher energy photons/electrons. Then you use an electric or mag field to sort out the ions given off. All this is done in a mass spectrometer, and after talking to somone who uses such a machine and he assured me that they can be much simpler and cheaper if it was already set up for isolating a specific element. You then aim the stream of silicon ions to a heated silicon substrate, and let it grow. <br /><br />All the other elements needed, metals for wiring and dopants, can all be isolated using this process, and dopants can be added to the wafer in the same way that the silicon is.<br /><br />Repairing the majority of radiation dama

 

[spacester]

Terrific first post, rjoshb, welcome to sdc!<br /><br />I’ve posted elsewhere on how to make solar cells from lunar regolith. The processes were pretty well worked out years ago by Geoffrey A. Landis. The Artemis Society is a terrific resource, some of that material is dated, but some is not. <br /><br />Getting the power to Earth is indeed the hardest part of the job. It seems clear to me that we will need extensive infrastructure before lunar-derived power is able to make a dent in Earth’s energy needs. We would need several massive orbital platforms to relay the energy as microwave or laser beams. So when lunar solar power is discussed it is usually discussed in terms of its usefulness in lunar operations, and as a starting point to begin building space power infrastructure that some day might lead to power on Earth.<br /><br />While we can get everything we need to build solar cells from lunar material, there’s no rule that says we can’t bring some of the materials with us. My proposal is to establish the capability to make glass (NOT fused quartz! <img src="/images/icons/wink.gif" /> ) and bring the silicon with us until such time as we can extract silicon more cost-effectively. Glass-making should be easy, and we can probably find a way to make structural elements with it.<br /><br />The reason we need to learn to make glass is that we can make solar cells that are 99% glass and 1% silicon. That to me is the way to get started: bring the silicon and the machines to turn lunar glass into solar cells. At the very least we need to get private companies looking at the technologies, we need several independent studies to be done actually, done from the perspective of a for-profit enterprise.<br /><br />IMO everyone here (Americans) should contact their congressperson and tell them to support Mike Griffin, especially in his efforts to spur development of the enabling technologies, such as glass-making, that we will need to do things o <div class="Discussion_UserSignature"> </div>

 

[pmn1]

IIRC then about 10 years ago the BIS published an article in Spaceflight about the possibility of asuperconducting power ring around the moon - I might still have the cutting and if i do i'll try and type a summary up.<br /><br />Here's the info on the article if you think you can get it on line.<br /><br />http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1988SpFl...30...48L&amp;db_key=AST&amp;data_type=HTML&amp;format=<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[l3p3r]

I expect the energy required to realise such a venture would take decades to be reclaimed by the system itself, but what an achievement it would be!<br /> <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Rather than the elaborate grain separation method described above, I'm thinking smaller, much smaller.<br /><br />What we need are some replicators of centimeter to micrometer scale, that will graze the regolithic plains, testing grains one at a time, keeping the good ones.<br /><br />It sounds slow on a per-bug basis, but imagine populations of billions and billions of these, building thousands of square miles of solar panels lying on the lunar surface, circling the lunar equator, and beaming microwave power back to earth. Each would be programmed to replicate x many generations and then stop and convert their excess mass into solar cells.

 

[josh_simonson]

The earth has millions of square miles of useless desert, I'd expect these areas to be filled with solar panels before the moon ever is. The reason we don't have massive solar farms isn't that we lack a place to put them, rather it's because the installation and operation cost/kW is still too high in relation to other systems.

 

[mlorrey]

You are spot on, Josh, but what costs are we talking about, and with what methods? Current chemical industrial methods here on earth produce an unacceptable amount of pollutive externalities. As there is no lunar "ecosystem" to worry about up there, we don't have that concern on the moon.<br />Earth bound production is also rather industrial, rather than viral. Using exponential growth of self assembling systems will drive the cost per W down to miniscule levels, but such methods are of course dangerous to even propose here on Earth. This isn't a good place to experiment with potential grey goo scenarios.

 

[nexium]

I don't know how close we are to making self replicating machines. The next step is having them forage for most of the raw materials. After that they need to build and instal solar panels from what they can find.<br />Microwave energy from the moon will be available only during the 11 hours out of 23.5 the moon is above the horizon where we need the power. If the power is produced near a spot on the equator, the beam will not be available 14 days out of each 28. Earth utilities will not pay more than five cents (average) per kilowatt hour, for rolling black outs.<br />We have been trying to make useful superconductors at liquid nitrogen or warmer temperatures for decades, apparently with little progess. The problem is worse on the Moon with day time temperatures about 125 degrees c.<br /> A rectenna on Earth needs to be about 100 square kilometers = 37 square miles unless an extremely large transmiting antenna on the moon is built. That is about the optimum size when the beam contains 100 gigawatts, (1000 watts per square meter is considered marginally safe for human exposure to microwaves) which is the peak demand of about 100 medium size cities or the minimum demand of 400? cities. Neil

 

[nexium]

We can build a 100 amp power line with up to ten million volts dc = one gigawatt that circles the moon at the equator. Only half of the moon gets sunlight, but that half walks around the Equator in about 27 days. Solar cells in series would feed the power line at intervals all the way around the Equator and kystrons in series would produce beams that would power moon habitats on mountans, up to 1000 kilometers from the Equator. Habitats in low moon orbit could also receive power beams. When a power beam, briefly, had no more useful purpose it could send wide band data to Earth or other locations as far away as the Oort cloud.<br />Until the concept is scaled up to far more than one gigawatt, it is not practical send energy to Earth because very large antennas are needed at both ends. Neil