POLL: Nuclear-Powered Moon Bases?

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Should Moon Bases Be Nuclear-Powered?

  • Duh! It's the cheapest, most effective way to go.

    Votes: 65 83.3%
  • One word: solar (plus two more words: no clouds!).

    Votes: 11 14.1%
  • This is nuts! We must not export such dangerous and dirty technology to another world.

    Votes: 2 2.6%

  • Total voters
    78
Status
Not open for further replies.
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TC_sc

Guest
neutrino78x":hmmavs7s said:
Another thing that has not been mentioned as far as nuclear on the Moon: during the lunar day, exhausting the heat would be difficult. The surface of the Moon can be 200 degrees centigrade.

--Brian
I'm sure the developers of the reactor had thought of this problem, and I had also thought about it. My solution would be to put a shield over the cooling panels to bring the temperature back down. Even during the day the shade temps are extremely cold.
 
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Boris_Badenov

Guest
TC_sc":1ywqufcz said:
neutrino78x":1ywqufcz said:
Another thing that has not been mentioned as far as nuclear on the Moon: during the lunar day, exhausting the heat would be difficult. The surface of the Moon can be 200 degrees centigrade.

--Brian
I'm sure the developers of the reactor had thought of this problem, and I had also thought about it. My solution would be to put a shield over the cooling panels to bring the temperature back down. Even during the day the shade temps are extremely cold.
Another route would be to just bury it.
Mentioned above was how a Solar Power net could provide as much power as one of these little nuke units, well then get 2, they are quite small. With the nuke units you don't need any storage systems with their accompanying failure modes.
Solar is an excellent source of green power on Earth. You don't need to go green in space. If you're afraid of radiation space is not for you because it is everywhere outside of our atmosphere & magnetosphere.
It's time to start turning Earth into a park. We could start moving all our industry to the Moon & L1 & all our mining to the Asteroid Belt & beyond today if we had the power to supply them. Nuclear Power & Nuclear Rockets are the only way we will be able to accomplish these goals.
 
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docm

Guest
MIT Technology Review link....



A Lunar Nuclear Reactor

Tests prove the feasibility of using nuclear reactors to provide electricity on the moon and Mars.


Researchers at NASA and the Department of Energy recently tested key technologies for developing a nuclear fission reactor that could power a human outpost on the moon or Mars. The tests prove that the agencies could build a "safe, reliable, and efficient" system by 2020, the year NASA plans to return humans to the moon.

A fission reactor works by splitting atoms and releasing energy in the form of heat, which is converted into electricity. The idea for using nuclear power in space dates back to the late 1950s, when they were considered for providing propulsion through Project Orion. In the 1960s a series of compact, experimental space nuclear reactors were developed by NASA under the Systems Nuclear Auxiliary Power program. But public safety concerns and an international treaty banning nuclear power in space stopped development.
>
 
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neutrino78x

Guest
Boris_Badenov":2taxw4dk said:
Another route would be to just bury it.
Well, that suggests a level of infrastructure up there that we don't have right now, right? You have to be able to dig a large hole with enough room to radiate the heat, etc. Seems like more trouble than it is worth for an initial base.

Mentioned above was how a Solar Power net could provide as much power as one of these little nuke units, well then get 2, they are quite small.
The problem is that the small ones are small in power as well. So you get two, now you have only 200 kW, that's only what, 10% more than what ISS has? Logic would suggest that solar can still do that.

It seems that the initial lunar base should be built in one of the places that gets sunlight 70% of the time, so you don't need a large energy storage system (I understand this to be NASA's plan at this time). 50 years from now or later, when you have the capability to build a large, 1 MW + nuclear reactor entirely in space, or at least the fuel rods, if the energy storage has not improved by that point, then yes, I suppose you can go crazy with the nuclear power. I am just not convinced that the power requirements on the Moon are ever going to justify a large nuke, and a nuke that is small in size is also small in power.

With the nuke units you don't need any storage systems with their accompanying failure modes.
Yes, but instead of energy storage failure modes, you get reactor failure modes.

You don't need to go green in space.
You do need to be safe at the launch site, and safe in space. I don't want anything radioactive on a rocket that could explode on the launch pad. If you're launching it via a non-explosive method, such as laser launch, maglev launch, etc., that's fine, but putting a large nuke on a rocket is not going to happen, imho. Nukes are not inherently dangerous if done properly, but I think part of doing it properly is not launching a big one on a rocket from earth.

We could start moving all our industry to the Moon & L1 & all our mining to the Asteroid Belt & beyond today if we had the power to supply them. Nuclear Power & Nuclear Rockets are the only way we will be able to accomplish these goals.
I don't see the Moon as a place for industry/mining, I see it as being like Antarctica. I do see the asteroids and Mars as a place for that, and on the asteroids, yes you would probably need nukes. You may need it on Mars also, although a lot can be done with solar thermal and geothermal. But I still don't think it is a good idea to launch them from earth.

--Brian
 
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TC_sc

Guest
neutrino78x":pm0tk2cz said:
You do need to be safe at the launch site, and safe in space. I don't want anything radioactive on a rocket that could explode on the launch pad. If you're launching it via a non-explosive method, such as laser launch, maglev launch, etc., that's fine, but putting a large nuke on a rocket is not going to happen, imho. Nukes are not inherently dangerous if done properly, but I think part of doing it properly is not launching a big one on a rocket from earth.
I m no expert in this area, but from all I have read, the nuclear fuel at launch will not be that radioactive. They will use enriched uranium for the fuel. Enriched uranium is basically concentrated uranium. Uranium is a natural element that you mine from the earth. My understanding is, you don't get the extreme radiation until you start the fission process. The waste material is highly radioactive, which really doesn't matter once it's buried on the moon.

We build black boxes for airliners that blow up and fall thousands of feet, yet almost always they can retrieve the data from the devices. Launching a few pounds of enriched uranium is the least of my worries. If we don't end this fear of launching fissionable materials, we will never be able to explore the solar system. In that case we might as well even skip trips to the moon and give up space exploration all together. Forever we will be bound to LEO.

We must have nuclear to explore the solar system and beyond. Some say that Earth has only 2000 years left. It's time to kick up the effort to send the human race out to find other worlds.
 
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Boris_Badenov

Guest
Well, that suggests a level of infrastructure up there that we don't have right now, right? You have to be able to dig a large hole with enough room to radiate the heat, etc. Seems like more trouble than it is worth for an initial base.

It’s absolutely amazing what you can do with a shovel, even in just a few minutes. :D

The problem is that the small ones are small in power as well. So you get two, now you have only 200 kW, that's only what, 10% more than what ISS has? Logic would suggest that solar can still do that.

Exactly how much power did the ISS have available on day 1?

Yes, but instead of energy storage failure modes, you get reactor failure modes.

The reactors we’re talking about are simple, small & sealed. The Solar outfits on the ISS that you seem to be referencing have already had problems in orbit without the accompanying lunar dust.

I don't want anything radioactive on a rocket that could explode on the launch pad.

Do you drive a car?

that's fine, but putting a large nuke on a rocket is not going to happen, imho. Nukes are not inherently dangerous if done properly, but I think part of doing it properly is not launching a big one on a rocket from earth.

The problem is that the small ones are small.


??? Make up your mind ;)

I don't see the Moon as a place for industry/mining, I see it as being like Antarctica.

I don’t. We’ll just have to agree to disagree. :mrgreen:
 
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PiotrSatan

Guest
Nuclear energy is most efficient source of energy on Earth. I heard that there are presumed reserves of uranium that would supply us around billion of years with current needs. The needs decrease as technology goes up. My point is being that nuclear energy is great invention and good energy supply. Base on Moon may need *much* of uranium to start running. In my opinion there should be a hybrid. Solar power as first-grade source of power (because solar energy is not able to be held for a long time as uranium) and if base runs out of solar power, use nuclear power as back-up. This way we can save our uranium resources on Earth for other needs instead of mindlessly depleting them faster. Nuclear waste could be cleaned up to make it no longer radioactive and could be used as material for things like: toys or cups...

(not sure about that part now)
Also gases emited from the power plant would make Moon get bigger atmosphere, with CO2 in it. It could be used for terraforming purposes in not-so-distant future.

I am open to critic now. :p
 
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neutrino78x

Guest
Boris_Badenov":1dtokaut said:
neutrino78x":1dtokaut said:
The problem is that the small ones are small in power as well. So you get two, now you have only 200 kW, that's only what, 10% more than what ISS has? Logic would suggest that solar can still do that.
Exactly how much power did the ISS have available on day 1?
I'm not sure, but that's my point. A base on the Moon would be built up over time.

Boris":1dtokaut said:
The reactors we’re talking about are simple, small & sealed. The Solar outfits on the ISS that you seem to be referencing have already had problems in orbit without the accompanying lunar dust.
Right, the reactors we are talking about are small: small enough that solar does the job they would do. A "portable" reactor that does significantly more than what solar does -- say, over 1 MW -- would not be "simple, small and sealed".

To my knowledge, given present technology, you have two choices: reactor is too small to justify, or reactor is powerful, yet too massive and dangerous to launch on a rocket.

If you want to use that 40 kW or 100 kW reactor, you have to dig a large hole so that it has enough space around it to radiate heat during the lunar day, and you have to locate it sufficiently far away from the base so that the lunar regolith shields it. This is probably going to be over 2 m deep, and below that however much space is needed to put the radiator and be able to safely radiate the heat, as you can't radiate it to space during the day, and at least 3 or 4 m away from the base. As we said on submarines, "time, distance, shielding". You're not going to have a backhoe or anything like that on a first Moon base.

Having said that, am I an anti-nuclear nut who is against ever having a nuclear reactor on the Moon? No. Once we have the tools etc located on the Moon to put something like that there, and if at that point the energy storage methods have not evolved to the point that a nuke of significant power is unneeded, by all means, use it.

However, it is also true that I do not think it is needed or practicable on the initial base. For an initial lunar base, you want an area that gets sunlight most of the time, because solar power is the lightest and most practical method of generating power in Earth orbit. It is a proven method of powering things there. If we start building a lunar base up there next week, it is going to be solar powered. We're not going to be digging large holes or small holes or anything like that for the initial base. It is going to be a series of small modules, probably the size of the Altair lander or smaller, and it will either be built in an area that is not subject to the 14 days of night (polar region etc.), or it will have some method of energy storage which lasts that long.

The Wikipedia entry on NASA's proposal for a lunar base claims that NASA has already stated that the initial base will be solar powered. Which, IMHO, makes the most sense. Nuclear power on the Moon, if ever needed, is for the future.

Same for Mars: though I see Mars as eventually having independent nations there, and heavy industry, and it may or may not eventually need nuclear power, the first mission is going to be solar powered.

--Brian (I don't know how to drive a car, but I am qualified helm/planes watch on the USS Florida SSBN-728. (it has since become SS*G*N-728))
 
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TC_sc

Guest
Nasa should pay us to be its think tank:)

Okay I am convinced it's solar and nuclear. Clearly, at first the outpost will be solar. I don't see a need for nuclear until there is a permanent manned facility. The reactor can be started and shut down at will. It can be the supply for the 14 day nights, or just as a back up. You just never know when a mean ole solar storm is going to wipe out a large percentage of those photo voltaics. ;)


Also, doesn't it take a lot more fuel to do a polar landing on the moon? I know in the Apollo days they couldn't do a polar landing. My guess is that it takes more energy requirements to do a polar orbit of the moon. Does someone have more info on this?
 
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emudude

Guest
Building a cheap structure on the moon is actually remarkably cheap if you use bore holes and high explosives. The only man-made device that you need to bring is an airlock module which would sit on top of your moon cave like a cork in a wine bottle. Nuclear technology is easily the best way to go - and to whoever said that you need to store "nuclear waste" somewhere, considering that the entire surface of the moon that is exposed to the sun is being constantly irradiated, I don't think we have too much to worry about there ;) - besides, scientists will tell you that there's no such thing as nuclear waste. With fusion-fission hybridized reactors, all of this material can be recycled and reused. The key is to get as many countries benefiting from this as possible so that we can use things like nuclear generators without posing security threats.
 
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neutrino78x

Guest
TC_sc":37uwz3w1 said:
Okay I am convinced it's solar and nuclear. Clearly, at first the outpost will be solar. I don't see a need for nuclear until there is a permanent manned facility. The reactor can be started and shut down at will. It can be the supply for the 14 day nights, or just as a back up.
I definitely agree in terms of the initial outpost. Like I said, putting a nuke up there would be something you do when it is needed, you wouldn't want to do it as one of the first things that goes to the new base. I envision a pod, like the Antares lander, with its own solar power, being landed in one of those areas where there is sunlight more often.

I seem to be in the minority in this thread in wanting the Moon to be treated as an international park, like Antarctica. I have that opinion because it is the body which orbits the Earth. I also think that other places in the solar system, primarily Mars, have natural resources which are more conducive to colonization.

--Brian
 
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ZenGalacticore

Guest
I'm all for nuclear power on the living Earth. So of course I'm all for it on our lifeless, barren Moon. Besides, I have faith that we will one day achieve controlled nuclear fusion. At that point, we'll have unlimited energy and be able to remove whatever radioactive waste sites that we had established on the Moon to "other" locales in the solar system.
 
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Shpaget

Guest
It seams to me that you all see only two options nuclear trashcan thingy or solar panels.
And when you hear solar panels you only think of photovoltaics. Those are the ones that produce electric power.

But why wouldn't you take that sterling engine from the nuclear trashcan (that one is probably state of the art) and point a few mirrors at it. You would get your heat, just like from nuclear source, only without all the nuclear stuff and shielding that probably makes the majority of 1200 kgs of original design. Since there is no wind on the Moon those mirrors can be very delicate and lightweight, and they can be easily replaced. You can even manufacture spare ones from the lunar material.
You can make entire sterling engine out of lunar rocks, but I don't thing you can make solar panels.

We all know that photovoltaics have poor efficiency, so you would probably need significantly smaller area of mirrors than solar panels to produce the same amout of power.

BTW, I have nothing against nuclear.
 
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TC_sc

Guest
Shpaget":1f7mutl7 said:
It seams to me that you all see only two options nuclear trashcan thingy or solar panels.
And when you hear solar panels you only think of photovoltaics. Those are the ones that produce electric power.

But why wouldn't you take that sterling engine from the nuclear trashcan (that one is probably state of the art) and point a few mirrors at it. You would get your heat, just like from nuclear source, only without all the nuclear stuff and shielding that probably makes the majority of 1200 kgs of original design. Since there is no wind on the Moon those mirrors can be very delicate and lightweight, and they can be easily replaced. You can even manufacture spare ones from the lunar material.
You can make entire sterling engine out of lunar rocks, but I don't thing you can make solar panels.

We all know that photovoltaics have poor efficiency, so you would probably need significantly smaller area of mirrors than solar panels to produce the same amout of power.

BTW, I have nothing against nuclear.
To run a sterling engine you need only a temperature differential. You can get that with radiator panels and a shade. I would think that if using solar and a sterling is more efficient, why isn't the ISS using it? Lots of sun to be had in LEO. I would think its going to take a lot of mirrors or radiators to equal the BTU you get from the trashcan nuke.
 
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Shpaget

Guest
What's BTU?
Considering that Sun gives approx 1400 w per square meter, lets say you can use only 500 due to various losses. You would only need a 10x10 m array of mirrors to match nuclear thingy. Even if you had to double the area, it would only take a square 14x14 m.
You would need the same amount of radiators as you do for the nuke.

Why they don't use sterling on ISS?
I wouldn't know. Maybe because they don't want all that heat anywhere near delicate equipment and station insulation. Maybe because sterling engine would require lubrications of moving parts but they can't lubricate it in vacuum so it would need to be indoors occupying too much space and heating up entire station. Who knows.
 
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Boris_Badenov

Guest
A Sterling Engine does not create heat, it uses tempurature differential to operate. Additionally, if Sterling Engines are so efficient, why don't we have them on every building?
 
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TC_sc

Guest
Shpaget":3fa2b4jv said:
What's BTU?
Considering that Sun gives approx 1400 w per square meter, lets say you can use only 500 due to various losses. You would only need a 10x10 m array of mirrors to match nuclear thingy. Even if you had to double the area, it would only take a square 14x14 m.
You would need the same amount of radiators as you do for the nuke.

Why they don't use sterling on ISS?
I wouldn't know. Maybe because they don't want all that heat anywhere near delicate equipment and station insulation. Maybe because sterling engine would require lubrications of moving parts but they can't lubricate it in vacuum so it would need to be indoors occupying too much space and heating up entire station. Who knows.
BTU = British Thermal Units. It's the heat required to raise 1 pound of water 1 degree.

You are really talking apples and oranges. If like you say, you might need 500 of your 10 X 10 meter panels, thats 50,000 square meters of panels. When using the sterling, no matter how much heat you use, you have to have just as much cold. I know I can get pounded for using the word 'cold', but few understand there is no such thing :p An array of focused mirrors would run the sterling quite well, but again, you are going to need a lot of them. You are going to need a tracking device so they can follow the sun. No matter what solar you use, you will need to have those tracking motors. Solar is a proven technology, but no matter how you deliver it, it's bulky.

They do use lubricants in the harsh environments of space. There is little difference between space and the moon's surface as far as lubricants go. Not much difference in any respect, other than the slight difference in gravity.

One thing to remember in, whether in LEO or on the moon, you have only radiant heat. It's a totally different world than where you have an atmosphere.
 
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Shpaget

Guest
I'm afraid you misunderstood me.
When I said
Considering that Sun gives approx 1400 w per square meter, lets say you can use only 500 due to various losses.
I estimated that you can use 500w/m^2 due to losses. Not that you would need 500 mirrors.
Entire array would occupy only 10x10 meters to provide 40 kW.
Since the nuclear powered sterling is seriously considered by NASA, I would assume that they figured out hot to get their "cold" or should I say lack of heat. :p

An array of focused mirrors would run the sterling quite well, but again, you are going to need a lot of them.
Like I said, only 10x10 meters of them.
I don't see tracking device as a problem. You don't need to worry about winds so everything can be simplified and reduced gravity should also help.

I know that there are lubricants that work in space, but are there lubricants that work in space and are immune to extreme heat, one could expect in such an engine, at the same time? That's what I'm talking about. Lubricants usually lose their lubricating properties when exposed to high temperature.
I didn't say that environement around ISS is significantly different than on the Moon, I just mean that I believe that it is far simpler to presurize a "room" in which to keep that sterling engine if the lubrication requires atmospheric pressure. You also don't get heat buildup you could get in a space station next to your living quarters, since it can be separated, unlike in ISS.

One thing to remember in, whether in LEO or on the moon, you have only radiant heat. It's a totally different world than where you have an atmosphere.
Are you saying that there is no infrared radiation on the surface of the moon that could be harnesed?
Significant difference is only in the cooling departement, as far as I know, and NASA obviously figured it out. You wouldn't need any more of radiators/cooling elements than that nuclear reactor requires.

A Sterling Engine does not create heat, it uses tempurature differential to operate. Additionally, if Sterling Engines are so efficient, why don't we have them on every building?
I know it doesn't create heat, but ,like you said, it does need it to opreate. And bigger the temperature difference, more it produces.
Sterling engines are not all that efficient (30-40%).
And some people do have them in their back yards.
 
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neutrino78x

Guest
TC_sc":3jf2yyog said:
To run a sterling engine you need only a temperature differential. You can get that with radiator panels and a shade.
Well, you also have to remember how hot the moon is during the daytime. So your shade has to be sufficient to make it cold enough under the shade that the radiator is effective. That, or you could always use the nuke only at night. That's probably the best way, also you have to place it far enough from the base that you don't have gamma radiation reaching you. Otherwise you have to bury it, and you won't have the machines to do so at the initial base.

I would think that if using solar and a sterling is more efficient, why isn't the ISS using it? Lots of sun to be had in LEO. I would think its going to take a lot of mirrors or radiators to equal the BTU you get from the trashcan nuke.
Well, solar thermal is VERY efficient, much more efficient than PV for large scale. Large scale solar power on Earth has to be solar thermal because it is more efficient. Since the trashcan nuke only makes 40 kW, it wouldn't take a large mirror. Somebody with the appropriate degree can do the math for us, I think somebody said 10 m^2, that's probably the same size as the radiator you would need for the nuke.

The reason the ISS doesn't use it is that PV has fewer moving parts, is lighter, and doesn't have to be aimed with precision, etc.

Again, with the solar you have the issue of energy storage. I would suggest either a container you can put regolith in, or a container with a salt solution brought from Earth. Then you focus the light on it during the day, and hopefully it radiates the heat for 14 days after the Sun goes down. The more energy storage you want, the more heat storage medium you need.

This is why NASA plans to have the first manned lunar base at one of the areas that is not subject to a 14 day night, so you can simply use solar panels for power and eliminate this whole issue.

--Brian
 
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neutrino78x

Guest
TC_sc":1tdlfypx said:
BTU = British Thermal Units. It's the heat required to raise 1 pound of water 1 degree.
It is also not a metric unit. The scientific equivalent to BTU is joules (specifically, 1 BTU = 1.06 kJ).

No matter what solar you use, you will need to have those tracking motors.
That's wrong, dude. Modern PV works just fine without tracking motors. Try a solar powered calculator, move it around as much as you want, as long as the sun is illuminating it, it works just fine. QED.

Solar thermal probably needs it, depending on how it is designed.

Solar is a proven technology, but no matter how you deliver it, it's bulky.
Certainly not...solid state PV is MUCH less mass than a nuke. The advantage of the nuke is that it can generate power during the 14 day night, not its mass. Its mass is a downside.

One thing to remember in, whether in LEO or on the moon, you have only radiant heat. It's a totally different world than where you have an atmosphere.
Yes, solar is much easier/more efficient in orbit and on the Moon than on Earth, because the atmosphere is not attenuating it.

--Brian
 
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neutrino78x

Guest
Boris_Badenov":22pql0o0 said:
A Sterling Engine does not create heat, it uses temperature differential to operate. Additionally, if Sterling Engines are so efficient, why don't we have them on every building?
Because most buildings are hooked up to the grid, dude. Plus, PV is flat and solid state, so you can put it on your roof. It would be hard to use solar thermal on your roof, unless you had a flat one, I guess.

You can use solar thermal in your backyard, as long as the backyard is illuminated by the sun the entire day. It would look like a 2 m "big ugly dish" satellite dish, except it would have a mirror (the dish would be a mirror), and a stirling engine at the focus of the mirror. You wouldn't want to look at the dish too often, lol! Observe:

Raw Solar (Portable Solar Thermal Company]

You can also cook food that way. If you have a parabolic mirror that can be flattened and put in your backpack, you could cook food in the wilderness without a fire, as long as you had a clear view of the sky. The sun gets really hot if you focus it, as anyone knows who used to burn leaves with magnifying glasses. ;-)

Solar Cooking International
Solar Cooking Info

odd that in a space group, a lot of people are ignorant of the power of the Sun...haven't you guys ever watched The Man with the Golden Gun? lol...

speaking of which, that would be another way to store power from solar, the way they do it in that movie, with superconducting inductors. Except, since that movie came out, we now have liquid NITROGEN superconductors. ;-) Unfortunately, it is normally not a dense way to store energy. But they do use it to condition grid power in some places.

--Brian
 
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TC_sc

Guest
neutrino78x":3kzmfkfs said:
That's wrong, dude. Modern PV works just fine without tracking motors. Try a solar powered calculator, move it around as much as you want, as long as the sun is illuminating it, it works just fine. QED.

Solar thermal probably needs it, depending on how it is designed.
ISS uses motors to keep the PV panels pointed toward the sun.

I used t know the loss of efficiency at certain angles to the sun. Yes there is lots of IR on the moon for the PVs :)

None of the debates are if solar will work. The debate is which is more efficient to launch and use.


I'm losing track of threads I am posting to :) So I am tossing this in here. I have heated standard industrial grease to a more than 1000 F. There is always graphite lubricants for extreme temps.

Oh yes I am still hoping someone can tell me the increase in fuel, if any, for lunar polar missions.

On the moon any shade during the daylight hours is well below 0 C. Finding cold for the sterling engine is as simple as a beach umbrella :lol:


Good debate guys :)
 
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neutrino78x

Guest
TC_sc":3orr90ld said:
Oh yes I am still hoping someone can tell me the increase in fuel, if any, for lunar polar missions.
No idea, can't be that much because you just have to get into the right orbit then just float down there, but it is worth it because the water is there, and the sunlight is there. It is called ISRU = In Situ Resource Utilization. Why make the mission harder than required. Since solar is abundant at the poles, you can always send battery powered rovers to excursions in areas far away from the PV panels.

btw, for those who are still ignorant of the awesome power of the sun,

3624 BTU/hr, approximately 2 m dish, with a tree over it, cloud cover, and manual tracking.

There would be no tree or clouds on the Moon. No attenuation of the electromagnetic waves from the sun. 28 gallon (105 litre) tank was raised in temperature approximately 15 degrees F in 1 hour.

I think Mr. "you would need lots of mirrors" has been proven wrong. but I'm not done yet:

This one can melt STEEL. over 4,000 degrees F or 2,200 C.

Each one of these dishes is apparently 25 kW.

The way you store power with solar thermal, at least on Earth, is by circulating a salty fluid from one tank, into the dish to be heated, then into another tank, and once hot it retains the heat for some period of time.

Anyway, as I said, there are cases where nuclear power is required, but I don't think the surface of the Moon is an example, at least not for a basic scientific research base. Maybe if you had a large city there. You start requiring nuclear power when you get to the gas giant moons, or if you're making a ship that can go there in a reasonable period of time (a few weeks or less).

--Brian
 
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neutrino78x

Guest
TC_sc":3t2zm130 said:
ISS uses motors to keep the PV panels pointed toward the sun.
Actually I think they tilt the panels mainly for aerodynamic reasons. (they are in slight atmosphere to be protected from radiation). But as long as the panel is illuminated, it doesn't mind the angle.

I used t know the loss of efficiency at certain angles to the sun.
It is negligible with modern technology. That was 20 years ago. Like I said, get a solar powered calculator and try it. You will notice the calculator continues to work. Where I work, I have a solar powered calculator that I use mainly inside of a trailer, NO direct sunlight. Works just fine. And no it doesn't have a battery.

Yes there is lots of IR on the moon for the PVs :)
You actually need a special PV that is sensitive to IR if you want that, most of them use visible, they might be more sensitive to different frequencies depending on what technology you're using...But yes, in daylight on the Moon, there is a lot of IR. It is very hot on the surface of the Moon in daytime.

But you mention IR, that is a good point, because they are working on IR photovoltaics which will be more efficient than stirling engine, mainly for use in a RTG, but it would be useful in this context also (solar thermal).

None of the debates are if solar will work. The debate is which is more efficient to launch and use.
Of course, because solar has 30+ years of working. It is assumed solar will work. The burden of proof is on the side of people who think a nuclear reactor is needed. The burden of those of us who want to use solar is to show a method of storing the energy that is good enough. But the first lunar base would be in sunlight 70+ percent of the time so solar would be fine...

On the moon any shade during the daylight hours is well below 0 C. Finding cold for the sterling engine is as simple as a beach umbrella :lol:
It is shade for the radiator (waste heat from the chain reaction) I'm worried about. You can't radiate into 200 C.

--Brian
 
S

Shpaget

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The angle of PV in nowhere near negligible. Please observe, this artwork:

Yellow lines (which are equaly spaced in all three examples) represent rays of sunlight. Black lines, which are once again equally long, are PV.
In the first case, where PV is perpendicular to the rays (90°), we can see that all sunlight is captured.
In the second, the angle is 35°. Almost half of the light goes by.
In third the angle is 20°. Only one third of light is used.

You can even calculate it exactly using sine function (sin).
sin 90° = 1
That means one whole, or 100%.
sin 35° = 0.57
Meaning 57% of total surface of PV is used.
sin 20° = 0.34
Only 34% is effectively used.

You can easily see that angle does matter. The reason why your pocket calculator works no matter how you turn it is because of two reasons. One being diffuse reflection of light in Earth atmosphere which leads to illumination of objects from all sides, even if they are in shadow.
The second and more important reason is the fact that your calculator does not need all the power PV produces in direct sunlight because that PV was designed to supply more than enough power even in poor light.

Solar panels on ISS are constantly adjusted to be most effective, although there is a "night mode" that turns them parallel to the speed vector to decrease drag when there is no need for all the power they produce.
 
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