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Look, it doesn't matter where you get the power if you can't move substantial masses with the ion pump. You would need an ion pump at least A Million Times the capacity of the best ion engines to even break even with small cheap rockets.
This is not a reasonable goal
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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I think one could be built for 10 million dollars, and more than double the payload of the shuttle over a one week period of operation using two megawatts of continious power.
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And I would call this a silly estimation... it would take about five times as much (ionzation energy of 20.74 million moles H2 at 585kJ/mol with 15% tankage vs shuttle) to just ionize the stuff, much less move it, confine it, or liquify it.
ALSO where do you intend to get an ion pump thats Twenty Three Million Times as efficent as the best ion engine?
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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ERRORIST, you need to drop the whole ion engine idea - it's not going to work. Ion engines already operate at nearly 100% efficiency so you're never going to get the efficiency you need. Furthermore, there's no way to get the ion engine output to go into the nanotubes. The nanotubes won't be able to carry th hydrogen through their center and you'll just burn the nanotubes up with the ionized hydrogen anyway.
Your original idea was more practical. Assuming a pipe one inch in diameter made of carbon nanotubes or some equally exotic material. Start pumping hydrogen into this tube. As you pump hydrogen, the upper level will eventually rise as you increase the pressure below and keep dumping H2 into the bottom. Eventually, the pressure at the bottom will be great enough to liquify the hydrogen. We can then start basically push a column of liquid H2 up towards geosynchronous orbit.
I might be missing something here but given the density of liquid H2, you'll need a pump at the bottom capable of generating about 355,000 pounds per square inch to drive your liquid H2 to the top of the tube. This is about 25,000 atmospheres of pressure. I'm not too familiar with the state of pumping technology but it might be theoretically possible to make a pumping system that could do this. The main problem is that high pressure H2 will diffuse through the metals that make up the pump and embrittle them over time. Also, the pressure corresponds to about 1GPa of pressure. However, you will need a fairly thick-walled nanotube pipe to withstand that stress. Assuming that you've got 100GPa tensile strength, you need walls about 0.1 inches thick for a 10-fold safety margin. So yes, it's theoretically posible but will require a number of technologies that have not been invented yet and may not even be possible to make.
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It doesn't have to be as efficent we are talking volume. It only has to pump that much more volume. The energy is almost free once the power stations are built.
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Wow, I thought it was not possible to pump it up as a liquid. Perhaps, the pump can be made of the same material as the tube??? I agree with you. It is possible.
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SBird,
Wow, I thought it was not possible to pump it up as a liquid. Perhaps, the pump can be made of the same material as the tube??? I agree with you. It is possible.BTW that is a very thin wall thickness for a pipe. It would help keeping the mass down.
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It can be done look 57,000 atmospheres. Also, a 800,000 psi hydraulic press.Double the pressure needed.
[http://www.chipr.sunysb.edu/eserc/RPESC … roup1.html]http://www.chipr.sunysb.edu/eserc/RPESC … roup1.html
[http://www.nature.com/nsu/991111/991111-11.html]http://www.nature.com/nsu/991111/991111-11.html
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Yes, 50k atmospheres can be done but that's really pushing the limits of what you can do with steel and other metals. Basically, you'll probably have to make your pump out of solid diamond to get it to be able to withstand the stresses.
It is possible to pump the H2 up to orbit. I think that GCNRevenger was assuming the use of real technology. Solid diamond pumps are not real technology - you can draw them on paper but building them is another thing altogether. Furthermore, the carbon nanotube pipe is also pure fantasy at this point. MAYBE in 20 years we will have the technology to make such a tube but my guess is that the technology will come around sometime between 50 years from now and never.
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The technolgy is here now here is a neat link:
Check out the graph just before page ten.
[http://www.niac.usra.edu/files/studies/ … dwards.pdf]http://www.niac.usra.edu/files/studies/ … dwards.pdf
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I really have my doubts still that its potentially possible to pump liquid LH all the way to orbit, you are talking about getting a column of the stuff straight up 400 kilometers, and nanotube fibers as strong as they are being pulled from the ends, they have a weakness... that they aren't too good at being bent, so I fear that the tube wall will simply burst if you make the tube like you would a space elevator.
And then there is the insulation to worry about, where the tube in the sunlight above Earth's atmosphere will probably get pretty warm, and could cause boil off difficulties.
And you still need a space station on the other end to recieve the stuff, and then haul it by tank to GEO, which you might as well haul up by tank straight from the ground in the first place.
Plus hydrogen at the kind of pressures you are talking about may start eating holes in the tube wall just from the sheer equilibrium stress.
And the magic pump has to be able to move ton quantities daily without leaking... if you leak raw hydrogen into the air at that pressure... boom.
All in all, a daunting technical feat which I doubt can be done for any reasonable cost.
And if you are going to build a space elevator anyway to support the tube, why bother? Just send it up in tanks. You would need to pump a metric ton a day just to break even with the DC-X rocket or 2-3 tons to compete with a light-weight space elevator.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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The pump can be place in a vacuum chamber no air inside for boom. The bonding of carbon is that of dimaond. It is so strong no leakage would occur in the pipe. If you can pump 8 pounds per minute then you would have 11,520 lbs in 24 hrs.This is about the rate of your kitchen sink.
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Actually no, the tube bonding is NOT like that of diamond. Diamond is tetrahedral alkyl sp3 bonded, CNT is planar aromatic sp2 bonded... and if anywhere along the tube breaks while you are still within a reasonable height of the tube, you will run into another weakness of CNT materials... flamability. Plus, diamond is also quite brittle, you can easily smash it with a hammer... CNT composits will be a little better, but at the high (50%) loadings and thin diameters, I have my doubts.
CNT material is good for being pulled from the ends, not for being bent from the sides.
You must be able to inject on the order of 1,500-2,000lbs per day even at this extreme pressure... I think you may be rushing head long tward the limitations of pump technology.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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The graph you mention is largely junk. The 1GPa milestone is a cool one, it must have happened fairly recently so I missed it. However, they are basing all those numbers off of one data point which is just moronic. Furthermore, if you look at the lines, the lower one is the one that assumes that you use regular nanotubes and as you can see - it goes nowhere near the 100GPa requirement. (also you really need 200GPa strength to ensure a good safety margin) The upper line basically is a wild-guees extrapolation of doing chemical modifications to the nanotubes so that they will stick to the glue better. HOWEVER, doing so puts defects in the nanotubes so that that they lose most of their strength. That work will never make a rope of sufficient strength to build a safe space elevator.
It's still cool work. The resulting ropes will have all sorts of uses from better suspension bridges and stronger buildings to better bullet-proof vests. However, it's just not good enough for space elevator work.
Another problem with the space elvator that I didn't even touch on yet is space debris. if one piece of space debris hits your hose, your whole system is broken. And yes, space debris will but carbon nanotubes. They may be tough but a bolt going 22,000 mph will go through those nanotubes like tissue paper. You can't put shielding on the tube since it's barely strong enough to hold itself up. Enough shielding to stop impacts would make the tube hundreds of times too heavy. This is a problem that the regular space elevator faces as well. However, for the space elevator, you have the advanntages of being able to use multiple ropes for redundancy and safety. If one gets cut, you'll still have several others that are holding you up.
Basically, what you've designed is a variant of a space elevator. The standard elevator has a nanotube cable that cargo cars run up and deliver cargo to geosynchronous orbit. You basically have a hollow elevator that you are pumping liquid H2 through. Therefore it is just as cheap to put the liquid H2 into a storage tank and have it crawl up a regular elevator. The standard elevator is much safer and damage resistant and requires less new technology than your pipeline idea.
I hate to be the voice of doom but your idea simply doen't work. Even IF it ever becomes possible to make your pipeline, the same technology lets you make a regular space elevator and that is just as cheap and efficient as your pipeline. Plus, it's safer and less trouble-prone.
It was a cool idea but most cool ideas just don't pan out when you start crunching the numbers. I've had plenty of cool ideas and 95% of them just fall apart when I look at them more closely. That's the unfortunate truth. What you have to do in that case is quit beating the dead horse and start brainstorming new ideas. Eventually, one of them will work.
But that won't happen if you stay on the sinking ship and try and breath life into a dead idea.
GCNRevenger: getting a 36,000 km column of liquid H2 is only feasible because liquid H2 only weighs about 7 kg per cubic meter. If you tried to push water up the same column, the nanotube hose would burst long before you even got to LEO.
The H2 should remain liquid even at above ambient temperatues at those pressures. I'd expect that it would gassify at the top but the overall H2 flux would equal the pumping rate at the bottom. The design would be cheaper in the long run becasue the energetics are equivalent to a space elevator but as mentioned above, you might as well carry the H2 up in tanks.
As for bend strength, the nanotubes are small enough that a 1 inch hose diameter might as well be flat as far as they're concerned. You'd get horrible H2 leakage through the walls of the tube, though. Also, the pressure involved might be enough to start getting spontaneous desaturation of the carbon bonds - basically the nanotubes would start spontaneously oxidizing the H2 and disintegrating. And yes, assimuing the magic pump could even be built, I wouldn't want to be within 10 miles of it while it's running. Forget flammability, a pinhole leak would have so much pressure that it would cut a building in half.
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I am sure such pumps exist today. Here is a neat article. There are even more powerfull ones out there.
[http://www.nature.com/nsu/991111/991111-11.html]http://www.nature.com/nsu/991111/991111-11.html
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I do happen to be typing this from the chemistry lab next to a pile of my graduate work, I know what desaturation is though my physics be a little rusty, but I imagine that the general audience doesn't ("eating holes in..."). I concur with you that the tube will likly develop leaks, especially with the tube under bombardment by cosmic radiation and UV light may help to speed this effect.
Good point about the hydrogen simply leaking between tubes, I doubt the glue could hold back that kind of force barring some crazy number of tube/tube covalent bonding. Don't forget Errorist that hydrogen is one of the smallest molecules there are.
If you could make carbon nanotubes of arbitrary diameter you could skip the glue alltogether, this is pretty far-fetched though and could only be done by massive atomic manipulation nanotech, which I have a feeling our childrens-children-children may not see, if ever.
Oh and i'd like to reiterate a little orbital dilemma, that the column of hydrogen would have to be transferred to tanks somewhere along the line, since the elevator itself isn't moving at the same free orbital velocity at less than GEO height, so you can't drive the rocket up to fuel station.
...i'm trying to imagine the firestorm when the pump leaks and that column of liquid hydrogen starts coming back down to feed the flames...
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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I would imagine there would be less in the tube than what the shuttle can hold at any given moment. Hey what if you aluminized the inside of the tube to prevent leakage?
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Reguardless how much you want to move per day, you still have to load the tube up to liquification pressures, so you can push that into orbit. There is a minimum operating pressure, and thats really d*** high.
No, aluminizing the tube will only slow penitration I imagine, at least if you make the aluminum layer thin/light enough not to weigh down the tube, which is questionable in the first place.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Can you ionize liquid helium then put the same charge on the tube?
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Forget the ion engine method, I have conclusively shown that it will not get you anywhere.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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ERRORIST, the pumps you keep referring to are operating at pressures that are 7 times lower than what's needed. Steel simply falls apart at the pressures your need. The only sort of mechanism that can withstand these pressures are diamond pressure anvils and they don't pump anything. Plus, decades of experience with diamond anvils shows that high pressure hydrogen tends to make diamond crack. The pump simply isn't practical. I'm a graduate student in materials science - trust me on this.
Aluminizing the tube won't help either. Hydrogen goes through metal like a sponge. If you have hydrogen supercooled to a liquid, it's not so bad but there's no way you will be able to keep your hydrogen that cool in your pipe. What you are working with is high pressure, high temperature liquid hydrogen which will soak through everything.
Ionizing hydrogen or helium WILL BURN UP THE TUBE. QUIT TALKING ABOUT IT! It doen't matter what the tube is made of either.
The pipeline idea is a neat one. But it requires technology that decades away and might not even be possible. Even if that technology is invented, hauling tanks of Hydrogen up a space elevator is inherently cheaper and safer.
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You can cool the liquid after it has become liquified.Perhaps, a coating of some sort can prevent the pump from cracking?.
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How about carborundum??
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You aren't thinking on the microscale... hydrogen molecules are extremely small. Other atoms are pretty big, like carbon that the tube or a all-diamond pump is made of or aluminum you seek to line it with... If you have loads of small particles like that under high pressues, it will probably permiate the material with its tiny holes between atoms and cause it to leak and ultimatly fail... Aromatic carbon (CNT kind) is less bad in this respect, but it will still fail from hydrogen attacking the carbon.
Boom.
You can cool it allright, but you can't KEEP it cold in the tube, and why would you want to?
Like Corundrm(sp?), Aluminum Oxide? Nope, that won't stop it either.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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How about beryllium?
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