3D printing on the moon

Very interesting indeed.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Sniper4395 Wrote:
-------------------------------------------------------
> The benefits arent exactly minor. H3 reactors
> would use fusion, not fission. That means no
> nuclear waiste will be produced by the power
> plants and instead Helium gas will be a byproduct.
> This alone makes H3 worthy of replacing current
> nuclear tech.

Yes, fusion is what I was talking about. Helium-3 is not a requirement for building fusion reactors. It has been portrayed as such by space development enthusiasts, but it's just one fuel among many and the much more commonly available deuterium and tritium fuse easier, at a lower temperature. As long as we don't even have working D-T fusion, He3 is completely useless.

> According to this it will cost roughly 115$
> billion to get up there and another 7$ billion a
> year to maintain an operation on the moon.
> Considering the price of H3 and the amount that
> could be safely mined and shipped to Earth the
> whole project could pay for it's self 10 fold.

The moon rocks are estimated to contain He3 in very small fractions of parts per million. The operation to mine a ton of He3 would have to process tens to hundreds of millions of tons of moon rock. It would be an enormous undertaking. It's very much on-topic, though, because shipping even the manufacturing equipment for building such an operation directly from Earth with inefficient chemical rockets would probably be infeasible. Shipping manufacturing equipment that can replicate itself from locally available materials (i.e. RepRaps) would most likely be the only way to make something of this magnitude possible.

The one thing I am always scared of with mining the moon (something I am 100% against but mining asteroids and comets I have no problems with) is that the surface of the moon will change. While you might not care I rather like the face of the moon and would hate to see it in my face each night looking like some of the mining operations on this planet. It isn't asteically pleasing at all.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

How about this one (as just an example) :

Additive Manufacturing of Copper Components with Selective Laser Melting

Quote

Selective Laser Melting

The additive manufacturing process, Selective Laser Melting SLM enables the fabrication of complex components, which
can, for example, have intricate internal structures. SLM uses laser radiation to process metals in powder form into
components whose mechanical properties do not differ from those made conventionally.

Results

Standard laser plants commonly have a maximum output power of 200 W, which enables the processing of working
alloys from aluminium, cobalt-chrome, titanium and a variety of steels. Due to the lower absorption of the laser radiation
and the larger heat conductivity of copper and copper alloys - in comparison to, e. g., steel - greater laser power is required
to process these substances than for the ones listed above.
At the Fraunhofer Institute for Laser Technology, a laser system with a maximum laser power of 1,000 W has been integrated into an existing SLM plant by adapting the optics, mechanics and control system. For the first time, this plant, using this additive method, is now able to produce components made of various copper alloys having a density of 99.9 %.

Applications

Through this new manufacturing method, the great heat conductivity of copper can be combined with any complex
internal structure, such as cooling channels. This enables the production of tool inserts that can be efficiently cooled. In this
way, so-called hot spots can be cooled more quickly. Thereby, the cycle time is reduced and any arising warpage minimised.
Other applications in which heat should be effectively removed can be found, for example, in the cooling of high performance semiconductor devices.

Maybe it's inevitable to use lasers for precise metal-3D-printing, although lasers generally have a high power consumption, which maybe a great disadvantage. Lasers can be used for heating as well as cooling, but they may be unpractical for home use.

Edited 3 time(s). Last edit at 12/10/2012 08:50PM by CrazyIdea.

Not only a high power consumption but they have to be super cooled which some of the coolants the stronger ones use I don't know if they are legal for home users to even have.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Quote
Dark Alchemist
The one thing I am always scared of with mining the moon (something I am 100% against but mining asteroids and comets I have no problems with) is that the surface of the moon will change. While you might not care I rather like the face of the moon and would hate to see it in my face each night looking like some of the mining operations on this planet. It isn't asteically pleasing at all.

In that respect it would be better to mine Mars instead of the Moon. We don't see the back side of the Moon on Earth though, so mining there wouldn't hurt the face of the Moon we see.

Edited 1 time(s). Last edit at 12/10/2012 08:49PM by CrazyIdea.

CrazyIdea Wrote:
-------------------------------------------------------
> The one thing I am always scared of with mining
> the moon (something I am 100% against but mining
> asteroids and comets I have no problems with) is
> that the surface of the moon will change. While
> you might not care I rather like the face of the
> moon and would hate to see it in my face each
> night looking like some of the mining operations
> on this planet. It isn't asteically pleasing at
> all.
>
> In that respect it would be better to mine Mars
> instead of the Moon. We don't see the back side of
> the Moon on Earth though, so mining there wouldn't
> hurt the face of the Moon we see.


My thoughts exactly even as I wrote the above BUT we know once there they would not stop. We don't own the moon so we would have very little influence on what another company, under a flag of a different non caring country, would do. Trust that they would pulverize the moon completely and ravage it just like they do on Earth only the moon is something like 1/6th (from memory) the size of Earth so everything done would look even worse and take less time to destroy it.

Here is some food for thought but what would happen to the gravitational force if we keep removing mass from it? The first effected would be the sea life that uses that force for many things. Screw with the sea and all life ceases to be if you screw it too much.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

... I'm using IR-diodelasers with some Watts (5 and 9Watts max, sometimes up to 25 Watts) of power to melt metal dust - this can easily be handled by a passive cooler and a wall-plug type power-source - so no fission-plant needed ... a 50Watts solar cell should be enough per laser

Have a fiber-laser with 50 Watts, that can cut through thin metal sheets with 30 percent 'wall-plug efficiency', so around 200Watts of power source and maybe 150Watts to cool away for this sort of lasers.

For mass-reduction by excessive printing-on-the-moon - calculate the weights of a 'typical' annual production of goods relevant for this sort of manufacturing that will be worth shipping to earth ... and then calculate, what is the average addition of mass to the moon per meteorite impacts over a year ... or direct one of the medium sized asteroids to the moon to add some gigatons more ...

... or start 'printing-on-the-asteroids', what will bring the benefit of lesser needed energy transporting the printet goods to any target in the solar system when using ion-driven mini-rockets

You're all thinking too much 'earth-based' - even when dealing with the moon

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Well, I was thinking about here on earth but on the moon, etc... the coldness of the dark side, or in space, would be enough to keep the heat down from the burning lasers (like Argon lasers).

Quote

The temperature on the surface of the moon generally ranges from 265F (130C) in sunlight to -170F (-110C) in darkness, because there is no air to hold in the heat like here on earth. Note that the high temperature is even above the boiling temperature of water, which is why it is impossible for water to exist anywhere on the moon that is touched by sunlight.

No real need when you are sitting there with temps slightly warmer than 'dry ice', to even less in space on a planetoid or comet.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Dark Alchemist Wrote:
-------------------------------------------------------
> CrazyIdea Wrote:
> --------------------------------------------------
> -----
> > The one thing I am always scared of with mining
> > the moon (something I am 100% against but
> mining
> > asteroids and comets I have no problems with)
> is
> > that the surface of the moon will change. While
> > you might not care I rather like the face of
> the
> > moon and would hate to see it in my face each
> > night looking like some of the mining
> operations
> > on this planet. It isn't asteically pleasing at
> > all.
> >
> > In that respect it would be better to mine Mars
> > instead of the Moon. We don't see the back side
> of
> > the Moon on Earth though, so mining there
> wouldn't
> > hurt the face of the Moon we see.
>
>
> My thoughts exactly even as I wrote the above BUT
> we know once there they would not stop. We don't
> own the moon so we would have very little
> influence on what another company, under a flag of
> a different non caring country, would do. Trust
> that they would pulverize the moon completely and
> ravage it just like they do on Earth only the moon
> is something like 1/6th (from memory) the size of
> Earth so everything done would look even worse and
> take less time to destroy it.
>
> Here is some food for thought but what would
> happen to the gravitational force if we keep
> removing mass from it? The first effected would
> be the sea life that uses that force for many
> things. Screw with the sea and all life ceases to
> be if you screw it too much.

You do realize that the Earth and the Moon are gaining mass all the time through 'space dust' falling into their gravity well, right? I don't have a number for the Moon's weight gain, but the Earth's is estimated to be about 40,000 tonnes per year. Assuming the Moon can only pull in 1/6 of the dust that the Earth can, that would mean that it gains 6.5-7K tonnes per year.

Fun fact: the Earth is actually loosing weight! It gains about 40K tonnes in weight per year from dust, but outgasses around 96K tonnes in hydrogen and helium from its atmosphere per year, resulting in a net loss of about 50K tonnes per year... None of which will have a noticeable effect on Earth's gravitational pull or tidal forces for the next several million years.

Considering how expensive it would be to transport a tonne of anything from the Moon to Earth, I wouldn't worry too much about changing the gravitational pull of the Moon by exporting material.


The same goes for massive changes to the Moon's features. Do yourself a favor and look at this composite photo of the Earth from a satelite in orbit. This was from pictures taken in December 2004. Can you see any Cities? Strip Mines? Roads? Any obvious signs of human habitation? I sure can't. It's a different story in the nightime because city lights produce more than enough lumens to be easily seen from space. However, in the day time you simply can't see any sign of human habitation from space without aids like telescopes.

Knowing this, what makes you think that the Moon will be any different? Assuming a sizeable population will even be able to live on the Moon permanently, all we would likely see are lights coming from the portion of the moon that is currently in shadow, which would look pretty awesome IMO.

Major strip mining on the surface of the moon, remember we aren't going to be the only game going up there, would indeed change the look of our satellite since what we are seeing are mountain ranges and asteroid/comet impacts but if you had say 20 countries/companies up there, or more, you can bet the impact would be seen by us. With a telescope I wouldn't be too surprised if you couldn't see them actually working if the telescope was high enough power. Fact is if you remove the mass something is going to give, like it does here on Earth, and it may not give inward but outward but the end result is the same.

Don't be so eager to go up there and start strip mining as the moon should be left damn well alone but, of course, it will not be due to greed.

Nice to know about the mass growing due to space dust but my point was that the little that it does grow would easily be offset with 20 nations up there pulling crap out and from it.

As far as actually seeing humans I know we will not unless we use the high power telescopes I mentioned but we would see their lights and that would suck ass as I don't want to see that JUST like I hate seeing the latest photo published from NASA (was reported on Yahoo last week) of all of the noise pollution from the US alone. I don't want to see it but eventually someone will as I don't think humans will be up there in any massive way for a very long time (longer than I have left for sure) but do remember we are talking about mechanized and robotized mining with little need for a human up there outside a few times a year but the mining damage will be done.

Just like on Earth they pump the Earth dry, mine it to oblivion without ever filling back in the holes they have left and they wonder why Earthquakes are getting more severe. Well, duh, the oil deposits in the planet act like large shock absorbers and without them you are now seeing a HUGE Earthquake in one part of the world and another massive one on the opposite side whereas before it was a HUGE one and a minor to way less severe than what is happening today. Luckily for us all there was not any dinosaurs up there that have now turned to oil or we would all be fooked in no time flat.

Edited 1 time(s). Last edit at 12/11/2012 03:00PM by Dark Alchemist.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Dark Alchemist Wrote:
-------------------------------------------------------
> Well, I was thinking about here on earth but on
> the moon, etc... the coldness of the dark side, or
> in space, would be enough to keep the heat down
> from the burning lasers (like Argon lasers).

The vacuum of space is an excellent insulator. Getting rid of heat while in space is non-trivial. Also, the dark side of the moon isn't any darker or colder than the near side of the moon.

---

Help improve the RepRap wiki! Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki!

Dark side of the moon is near Frozen Co2 temps so really cold and the warm side is warmer than boiling water. So the near side (light side) of the moon is hot, damn hot, while the dark side is damn cold. The in between would be fun as the temperature difference at the spot would be massive where you are freezing and your hand reaches out and burns away in the light just hitting your hand that made it into the light (like a vampire in the sun type deal).

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Overview

The moon is a stepping stone for us. We must take care of how we step. But stepping forward and out of the cradle is perhaps better than stepping all over each other?

The transfer of energy production and industrial manufacturing off-world is a worthy goal.

It offers a realistic long term hope for that ignorant, confused and immature child we call humanity.

The hope it offers is time, time for humanity to learn and mature.

So-called "sustainable" alternatives, while important, ultimately lead to an exhaustion of resources, a desperate chaos as we instinctually fight over the remaining scraps of our once rich world.

We have, just now, a moment in our history where our resources and our knowledge provide a small window of opportunity to step beyond this cradle.

That window that is already closing, yet I remain optimistic.

MikeJ

Overview

Dark Alchemist Wrote:
-------------------------------------------------------
> Dark side of the moon is near Frozen Co2 temps so
> really cold and the warm side is warmer than
> boiling water. So the near side (light side) of
> the moon is hot, damn hot, while the dark side is
> damn cold. The in between would be fun as the
> temperature difference at the spot would be
> massive where you are freezing and your hand
> reaches out and burns away in the light just
> hitting your hand that made it into the light
> (like a vampire in the sun type deal).


While the Earth's atmosphere does attenuate some of the energy we recieve from sunlight and its magnetic field deflects most of the harmful radiation, the amount of energy from sunlight you would see on the Moon's surface isn't all that much greater than what you get on the Earth's surface. The reason why you get such high temperatures on a lit surface in space is because a vacuum is a nearly perfect insulator as NewPerfection stated. The heat has no where to go and accumulates over time. The same in reverse goes for shaded surfaces. In a vacuum the only way to transfer heat away from you is to use heat radiation, which is not very effecient when compared to heat convection or heat conduction. It really is non-trivial to get rid of heat in space.

That said, the moon isn't 100% vacuum. There is a lot of solid material there too. Burrow down 10 meters or so below the surface and you have all this nice cold rock to transfer your heat to.

... or use this new found types of thermal gradient driven QC-lasers, that converts heat in laserlight and cools down the heat reservoir ... so more heat gives more laser-energy for working with

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

VDX, I am waiting for the new found technology that turns heat into light. It is done for transistors and the person who found this is the person who found the transistor so he says within 30 years we will have Integrated Circuits going into the petahertz range, or more, because all heat will be translated into light and the light can be used for transferring information as well. This startled me and made me so excited when I heard him speak about it. Not only because our computers will now get so much faster (we have hit a brick wall with silicon and can't take it any farther and why we aren't at 10 terahertz by now in our personal computers) but also for stuff like this. Take that and use that technology for something like this and wow.

As far as heat in space we already do it in our space suits via air conditioning and transferring anything in a vacuum is trivial but, as you said, the moon is not a 100% vacuum. The one thing scientists have worked on is deep space where it is so cold they think it is around 0k or at least so cold nothing will work for long as they would freeze up. They think possibly a nuclear reactor, or something akin to it, for the energy and heat it creates to semi counter the vast, and deep, cold. Remember in deep space super conducting could be a reality due to how cold it is and if at, or very near, 0K, as they suspect, it would be a matter of fact.

Edited 1 time(s). Last edit at 12/11/2012 05:52PM by Dark Alchemist.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Dark Alchemist Wrote:
-------------------------------------------------------
> VDX, I am waiting for the new found technology
> that turns heat into light. It is done for
> transistors and the person who found this is the
> person who found the transistor so he says within
> 30 years we will have Integrated Circuits going
> into the petahertz range, or more, because all
> heat will be translated into light and the light
> can be used for transferring information as well.
> This startled me and made me so excited when I
> heard him speak about it. Not only because our
> computers will now get so much faster (we have hit
> a brick wall with silicon and can't take it any
> farther and why we aren't at 10 terahertz by now
> in our personal computers) but also for stuff like
> this. Take that and use that technology for
> something like this and wow.
>
> As far as heat in space we already do it in our
> space suits via air conditioning and transferring
> anything in a vacuum is trivial but, as you said,
> the moon is not a 100% vacuum. The one thing
> scientists have worked on is deep space where it
> is so cold they think it is around 0k or at least
> so cold nothing will work for long as they would
> freeze up. They think possibly a nuclear reactor,
> or something akin to it, for the energy and heat
> it creates to semi counter the vast, and deep,
> cold. Remember in deep space super conducting
> could be a reality due to how cold it is and if
> at, or very near, 0K, as they suspect, it would be
> a matter of fact.

You seem to have completely missed the fact that it does not matter how 'cold' a vacuum is in space, you are still going to have big problems dealing with your heat. Heat can only transfer from one mass to another. A vacuum, by definition, has no mass. So, it is very difficult to get rid of your heat. If you are in deep space where you have an extremely low amount of energy in your volume of space you will still have trouble getting rid of your heat. All it means is that there will be little outside introduction of heat to your system (ship/spacesuit/body/whatever). You still have the problem of getting rid of it.

All space suits ever made don't actually try to get rid of the heat you generate. They just move the heat away from your body to another area of the suit for the length of time you are wearing the suit. Cooling superconducting materials is going to be an even bigger problem in space than on earth because there is no large mass to act as a heat sink for the heat that your superconductor is generating. A nuclear reactor is an utter nightmare to manage in space. Before everyone jumps on me by saying that there are nuclear powered satellites and probes today, keep in mind that the majority of the weight budget for such probes is taken up by the cooling systems, and even then it is only a realtively small amount of power/heat being generated, comparable to a 12V battery.

^^ Exactly. Massive radiators are required when generating any significant heat on a spacecraft. There's a reason that vacuum flasks insulate so well.

---

Help improve the RepRap wiki! Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki!

Interesting new JPL rock grappling tech: [www.youtube.com]
Anyone going to 3D print something like this?

PeteD Wrote:
> You seem to have completely missed the fact that
> it does not matter how 'cold' a vacuum is in
> space, you are still going to have big problems
> dealing with your heat. Heat can only transfer
> from one mass to another. A vacuum, by
> definition, has no mass. So, it is very difficult
> to get rid of your heat. If you are in deep space
> where you have an extremely low amount of energy
> in your volume of space you will still have
> trouble getting rid of your heat. All it means is
> that there will be little outside introduction of
> heat to your system
> (ship/spacesuit/body/whatever). You still have
> the problem of getting rid of it.
>
> All space suits ever made don't actually try to
> get rid of the heat you generate. They just move
> the heat away from your body to another area of
> the suit for the length of time you are wearing
> the suit. Cooling superconducting materials is
> going to be an even bigger problem in space than
> on earth because there is no large mass to act as
> a heat sink for the heat that your superconductor
> is generating. A nuclear reactor is an utter
> nightmare to manage in space. Before everyone
> jumps on me by saying that there are nuclear
> powered satellites and probes today, keep in mind
> that the majority of the weight budget for such
> probes is taken up by the cooling systems, and
> even then it is only a realtively small amount of
> power/heat being generated, comparable to a 12V
> battery.
Valid points indeed. This is why I love the new transistors I mentioned because we might be able to do that for other things as well. How cool would it be to have light instead of heat from things? For now, though, how would we handle it and the vastness of the dark void cold? In deep space we have to have something to raise the temps from 0K because at 0K everything ceases to move.

Edited 1 time(s). Last edit at 12/11/2012 09:13PM by Dark Alchemist.

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_______
I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

B9Creations Wrote:
-------------------------------------------------------
> Interesting new JPL rock grappling tech:
> [www.youtube.com]
> Anyone going to 3D print something like this?

... I've developed a methode and some prototypes, that can make this same 'gripping' or fastening of rough surfaces - but not with many single 'fingers', but with some small flat leaflets covered with hundreds to thousands of skewed needles, fibers or lamellas.

I've even filed IP's for an utility model for testing with IP-issues, but gave it free some years ago - attached scans of the head and drawings

When at home again, I can post some images of the prototypes and their usage ...

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

... found some of the images in an old user-gallery showing a really simple 'gripper' for rough surfaces and two of the moving prototypes.

Have another 'surface-gripper' with radial aligned leaflets, but no images online, so if someone is interested, I can post them later ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Why use fusion, when you can pave solar cells?
[www.highfrontier.org]

There's quite a bit of interesting manufacturing processes you can do in ubitquitous high vacuum.

You can even make structures from a concrete-like molten sulfur-regolith mixture using contour crafting:
[utwired.engr.utexas.edu]

Dark Alchemist Wrote:
-------------------------------------------------------
> Valid points indeed. This is why I love the new
> transistors I mentioned because we might be able
> to do that for other things as well. How cool
> would it be to have light instead of heat from
> things? For now, though, how would we handle it
> and the vastness of the dark void cold? In deep
> space we have to have something to raise the temps
> from 0K because at 0K everything ceases to move.


2nd Law of Thermodynamics states that in general the total entropy of any system will not decrease other than by increasing the entropy of some other system. Hence, in a system isolated from its environment (like in the vacuum of space), the entropy of that system will only increase. In dealing with energy that is moving or changing form, entropy = heat.

This means that any transistor, no matter how fast it switches or type of energy it uses, will generate heat. If someone is claiming to the otherwise, then your BS beeper should be going off in your head, and you should not be buying whatever item that individual is attempting to sell you.

Because of the 2nd Law of thermodynamics, you are also guaranteed that any ship in space that is active (light shining, electricity moving through circuitry, servos moving, thrusters firing, live people aboard, etc.) will be generating heat. While engineers at NASA and other space agencies may need to worry about it getting too cold for components on satellites/probes/ships to operate, none of them have ever worried about hitting 0K.

... here is the article about converting heat into laserlight (sorry, only in German): [www.photonik.de]

With this concept it should be possible to convert excessive heat into laserlight and so 'cheat' the local entropy by transferring the energy to another remote system (into empty space ... or using it for propelling the rocket ... or ...)

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

PeteD Wrote:
-------------------------------------------------------
> Dark Alchemist Wrote:
> --------------------------------------------------
> -----
> > Valid points indeed. This is why I love the
> new
> > transistors I mentioned because we might be
> able
> > to do that for other things as well. How cool
> > would it be to have light instead of heat from
> > things? For now, though, how would we handle
> it
> > and the vastness of the dark void cold? In
> deep
> > space we have to have something to raise the
> temps
> > from 0K because at 0K everything ceases to
> move.
>
>
> 2nd Law of Thermodynamics states that in general
> the total entropy of any system will not decrease
> other than by increasing the entropy of some other
> system. Hence, in a system isolated from its
> environment (like in the vacuum of space), the
> entropy of that system will only increase. In
> dealing with energy that is moving or changing
> form, entropy = heat.
>
> This means that any transistor, no matter how fast
> it switches or type of energy it uses, will
> generate heat. If someone is claiming to the
> otherwise, then your BS beeper should be going off
> in your head, and you should not be buying
> whatever item that individual is attempting to
> sell you.
>
> Because of the 2nd Law of thermodynamics, you are
> also guaranteed that any ship in space that is
> active (light shining, electricity moving through
> circuitry, servos moving, thrusters firing, live
> people aboard, etc.) will be generating heat.
> While engineers at NASA and other space agencies
> may need to worry about it getting too cold for
> components on satellites/probes/ships to operate,
> none of them have ever worried about hitting 0K.
In deep space scientists have stated that temps could theoretically hit 0 Kelvin so they a part in 0K is not going to work very well since 0 K movement ceases.

This is who I meant -> [www.npr.org] Listen to the interview fully.
This was the first interview I heard but was not the only one with this gentleman where he talked about this new thing. The other interview he went more in detail. Milton Fang and the transistor laser is what I am talking about and the mention and discussion of this part comes in at around 7:15-7:30 mark. So, I think I will listen to them over the so-called "law" of Thermodynamics. Remember laws are made to be broken.

---

_______
I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

VDX Wrote:
-------------------------------------------------------
> ... here is the article about converting heat into
> laserlight (sorry, only in German):
> [www.photonik.de]
> s-waerme.html
>
> With this concept it should be possible to convert
> excessive heat into laserlight and so 'cheat' the
> local entropy by transferring the energy to
> another remote system (into empty space ... or
> using it for propelling the rocket ... or ...)

Thanks for the link! I don't speak German, so I had to make due with what I could parse out of Google Translate. From what I can figure out, the system requires a low temperature zone and a high temperature zone, with the QCL at the interface between the two. Electrons excited by the hot zone travel through the QCL to the cool zone, imparting some of their energy to the QCL, which emits photons. So, it isn't the actual heat that is driving the QCL to emit photons, it is the difference in temperature between the hot and cold zone. Whats more, we have heat energy traveling from the hot zone to the cold zone. Correct?

If that is so, you cannot use vacuum as a 'cold zone', since it is insulatory in nature. That means you will need to have separate hot and cold zones on board the ship and a separate cooling system to pump the heat from the cold zone to the hot zone. No cooling system is 100% effecient... in fact they are very ineffecient, and will add a lot of additional heat to your system. Wether using QCLs to cool a ship in space will work will depend on the effeciency of your QCL, the volume of QCLs you can stuff into your interface between the hot and cold zones, and the effeciency of your cooling system. (edit: I forgot the most important part... it will also depend on the amout of heat all of your other ship's systems will be generating as well)

I don't have enough information to know if it is even possible or not. It certainly looks like a complex engineering problem, though.

Edited 1 time(s). Last edit at 12/12/2012 07:14PM by PeteD.

... as long, as you have to support a habitat and running electronics and machines and you're in 'local' space near the sun, you will generate or receive heat.

The 'cold-zone' would be defined by shadowed radiators - even if the vacuum is perfect for isolating contact heat, it won't prevent radiation of IR-photons into space, so the averaging temperature level will be something defined by the emmitance of the radiator surface, the EM-background of 3.5K and the interaction with local vacuum/solar wind, what's depending of the distance to the sun and should be low enough even in the earth's '20degC'-distance to give some usefull temperature gradient

IR-Radiation is a good methode to cool something down! - recently the scientists found water ice in the shadowed craters on Merkurs pole regions, where the surface is cold enough to collect and hold the ice stable since millions (billions?) of years!

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I'm a visitor, and I know very little about 3D printing except that it seems cool and utterly revolutionary, once the tech matures.

Now I've read here a whole lot of reasons why Lunar Mining of Helium 3 is not economically worthwhile, and a few counterarguments that it might be.
I've read a bit about city sized printers cranking out a Lunar Base.

But I'm surprised that no one has really gotten into the nitty gritty of a small-ish printer that can fabricate the components necessary for it to fabricate itself, then do so. It seems you'd need to be able to mine and fabricate using: Iron, Titanium, Silicon, Oxygen, and a few other minerals that we know are present in sizeable percentages on the Lunar Surface. Providing you could print a Mining Bot, a Refining Bot, Some sort of locomotive system, and replicate the Printer itself, you could potentially have an essentially endless supply of all the above, on the moon.

What would be the point? Where would the economic benefit be?
Well, you could print a railgun and sent the raw materials to the Lagrange point, (where you might have another 3D printer waiting) and from there into HEO. If you can print the solar cells and the Circuitboards (and, admittedly, the chips - which sounds REALLY tricky) you could prefab HEO/Geostationary Satellites and set them into orbit without burning any fuel at all. In fact, once the intial investment goes in, you should be able to do the above ad infinitum, almost for free save the cost of designing the sattelite. Much better than putting a payload on a heavy lift rocket - print it at the site, almost nil cost, and certainly no earth resource expenditure.
And once you have an exponential army of Lunar Mining Fabricators, you can start to do really large scale things, which might be worthwhile for Earth. Such as Space based Solar Power. Or my personal favourite, Extreme Weather Event Modulation - how much would a country save - how many lives could you save by turning the next hurricane away from the coast? Or Breaking a Heat Wave? Or breaking a drought? Or shading the Icecaps? Or cooling the Earth to arrest/reverse (?Anthropogenic?) Global warming? No way of sensibly doing any of the above without Space Based resources. And the moon is the only object in our vicinity with the mass to make enough stuff to do things at that scale.

And what would be the initial cost? Well, probably the price of the Apollo Program, plus whatever it takes to make a 3D printer capable of printing an Integrated circuit and a Solar Cell. Well within the capacity of, say, China.

Yes I understand that there are some reservations about this kind of thing. You wouldn't want weather control/manipulation in the hands of a dangerous adversary, obviously. Probably best left in the hands of the security council with a broad mandate to stop really bad weather, otherwise to leave it alone. And you don't want to wreck the Lunar Surface for aesthetic reasons. (Although you could easily choose to dig deep rather than across, thus alleviating some of the concern) But remember that this is to save our own meagre planet. And moving tech into the deep of space means more room for biosphere on earth.

Go on then, naysayers open fire!