Uses of Bulk Nano Materials (was beanstalks)

snipped-for-privacy@spsystems.net (Henry Spencer) :
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applies
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One problem I have with the person claiming that we will not have bulk NanoTube materials is that they seem to think all research is for thier use in beanstalks only. Ofcourse if this was true the amount of money and people devoted to the problems would be few indeed.
However the uses of such super materials is so wide that tens if not hundred millions of dollars a year are being spent because of the range of uses. Just about anytime that today is done with fiberglass or carbon firber structures could be done light and/or lighter with Nano materials. And a number of projects that today seem to be at the limits or even beyond the ability of present day technology become possible (IE a bridge link japan's islands).
There is plain too much money to be made by the successful producter of bulk Nano materials to believe that if it can be done that the method needed will be discovered.
Earl Colby Pottinger

snipped-for-privacy@gw.retro.com (George William Herbert) wrote:
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George, the patience of you and Henry even in the face of childish name-calling from people with clearly less sense in their heads than either of you carry in your left pinky toe is an inspiration. No matter how much the poster obviously deserves nothing but their own derision heaped back upon them, you answer calmly, rationally, and steadfastly to the point. Of course the net effect of this is to make the name-thrower look even more ridiculous than direct ridicule would do, yet at the same time, you demonstrate perfect netiquette and perhaps teach the more sensible onlookers a thing or two. I try to emulate your patience, but often fail, especially in the face of idiots like this one (oops, see, there I go again).
Pardon my gushing, but the presence of you, Henry, and a few others in this newsgroup raises its overall quality tremendously, and I wanted you to know that it's appreciated.
,------------------------------------------------------------------. | Joseph J. Strout Check out the Mac Web Directory: | | snipped-for-privacy@strout.net http://www.macwebdir.com | `------------------------------------------------------------------'

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what else can be expected from a macintrash user.

Vincent Cate wrote:
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Tensile strength of alumina whiskers is 42.7 GPa.
PS. This thread stinks! Even if cheap, long buckytubes are available, beanstalks/skyhooks will not be made for security reasons -- they are too easy to destroy. This is one reason why slings make much more sense than skyhooks. My favorite transportation system is made of a rocket which accelerates cargo to 2 km/s, a hoop electrotube (orbital eddy current contraption described in my space book), which accelerates the cargo to 4 km/s, and a bolo, which accelerates the cargo to 8 km/s.

Andrew Nowicki wrote:
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BTW, that is one of the major arguments put forward to stop construction of the Chunnel.

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Why are beanstalks pushed so hard when cheaper alternatives, like say rockets or even giant em guns are doable with todays technology? They certainly don't seem cheaper; Building a structure in space longer than the earth compared to doing the EM launch gun on earth over several hundred miles... The only appeal I can see is, 'look ma, all statics'

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Because the power needed compared to that for a rocket is much, much lower, as is the energy.
Rockets are currently higher than $1000/Kg.
There seems to be no theoretical reason why they can hit $1000/Kg (NASA seems to disagree, and hold it as one of their sacraments.
$100/Kg is more or less the fuel cost for optimistic assumptions. For a tether, it can go to $.1 for optimistic assumptions.

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And beanstalk launch costs are currently infinite (can't get there from here using that technology). A proper comparison is apples to apples; for example, if you propose to spend several billion on beanstalk development, you should compare to spending the same amount on rocket development, and if you propose a lean, efficient organization which doesn't have Boeing's overhead rates, you shouldn't compare the results to Boeing-made rockets.
There are lots of people who think they can get to $1000/kg -- the current guess for first-generation beanstalk payload costs, probably somewhat optimistic -- for less than a billion dollars of development money. That's an order of magnitude less than current estimates for the first beanstalk. You could fund five of them for less than a beanstalk, and at least one would probably succeed. (How credible are their estimates? Well, as Jordin Kare put it a year or two ago in a slightly different context: "they aren't Lockheed Martin, but neither are you".)
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There is no theoretical reason why rockets cannot get stuff into orbit for $5-10/kg. The only fundamental limit is that you need $3-4 worth of LOX plus a cheap hydrocarbon (kerosene, propane, whatever) to get a kilogram of dry mass into orbit, and some of the dry mass will be hardware rather than payload, and there will be some overhead for wear and tear on the hardware.
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Not unless you use unnecessarily expensive fuels. Even today's designs for SSTO RLVs -- SSTOs are fuel hogs, and current designs are only 15-20% payload at orbit injection -- shouldn't cost more than $20-30/kg if they burn LOX/hydrocarbon. Liquid hydrogen costs more but I don't think it would push them to $100/kg. To go that high you'd need to resort to hypergolics.
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Amortized over huge traffic volumes, yes, beanstalks unquestionably beat rockets. (And the crossover point occurs somewhat earlier if you figure in a cost for rocket emissions, like stratospheric water vapor during ascent and nitrogen oxides during reentry, both of which are bad for the ozone layer if flight rates get really high.)

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    I was looking at Ultimate Rockets (Rockets so advanced that the main cost is fuel) last year. As far as I could tell, LOX is cheap ($0.10/kg) and H is expensive ($3.60/kg). In a lot of the systems the H2 was -the- cost-defining expendible material used.
    For some reason I never got around to pricing standard fuels like kerosene.          In any case, I don't think you will use up $3-4 worth of LOX per kg of dry mass. Maybe of payload...

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Even that number is rather too high; it would be more like $0.02/kg if you were using it in sufficient bulk to justify your own LOX plant. The raw material, after all, is air...
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Yes, liquid hydrogen is fairly costly, not least because it's made from petroleum... (And the manufacturing process releases quite a bit of CO2 into the air, too.)
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Yes, that makes a big difference.
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Even with hydrocarbons, the fuel pretty much dominates the cost. LOX in bulk is almost free by comparison.

Henry Spencer wrote:
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No, it's made from natural gas, mostly.
    Paul

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Natural gas is just very light petroleum, light enough to be a gas at normal temperature and pressure.
Marc

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    Noodling around, it looks like a guesstimate of $0.20/litre isn't too far off and with a density about 0.7x water, that makes it very roughly $0.30 per kg.
    ISP of about 300, so m/r to orbit is about 14, so for C12H26 + 12.5 O2, the C12H26/O2 ratio is about 17/20 but since this is strictly BOTEC, we'll call it 1:1. Each kg of dry mass in orbit had 7 kg of C12H26 @ $0.30 and 7 kg of LOX @ $0.02 for a total of about $2.24/kg of dry mass. Say the equilibrium price for Ultimate Rockets is x5 the price of the fuel (planes are x3, I think) and that each kg of payload is but 1/10th of the dry mass and so each kg of payload is priced at $122/kg. Not bad: my massive ass could be put in orbit for about $8,500.00 or slightly more if I wanted to breathe while I was up there.
    Earth-Mars, call it 15 km/s delta vee, add in 10 kg/day of supplies to be pessimistic, for six months, for a m/r of 150, and a payload of 1870 kg, or about $300K if I have not multiplied incorrectly. The price goes up a bit if I demand frills like a re-entry vehicle, of course. And I have not budgeted for supplies to be used -on- Mars, possibly a problem. Like Franklin, I will have to rise to the occasion.

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No, I think you've forgotten that O2 is 32, not 16. C12H26 + 12.5O2 is a mass mixture ratio (oxidizer/fuel) of 2.35, which is around optimal for LOX/kerosene (depends somewhat on engine details).
If you've got a variable-expansion-ratio engine, you may want to go rather leaner -- most of the ascent is in vacuum, and for the high expansion ratio that you want to use there, mixture ratios around 2.9 are better. Higher mixture ratios are also denser, which reduces structural mass, so you may want to bias the mixture in that direction even at the expense of a bit of engine performance. The Ultimate Rocket might end up around 3.0.
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As above, it's about 10kg of LOX plus 4kg of kerosene, $1.46/kgdry. At a ratio of 3.0, it's $1.22/kgdry.
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Airline numbers depend on exactly *when* your data comes from; x3 is commonly quoted but may be a little optimistic. However, rockets ought to be better, not worse! Most of the costs aren't proportional to fuel -- magically tripling the fuel capacity of an airliner would not triple its operating costs -- and rockets are far more fuel-intensive than airliners. Max Hunter thought 1.2x ought to be feasible, long term, for reusable chemical rockets.
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That you can undoubtedly double, at least. If memory serves, payload was about 1/6 for the DC-Y design, *with* the dry-mass overheads of LH2 and *without* nanotube-material structures. I'd say the Ultimate Rocket is going to be at least half payload.
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With my somewhat-more-Ultimate numbers :-), it's $2.93/kg.

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    Whoops.
    Uh, I was just making sure everyone was reading carefully (That's gotta work some time).
    clip bad assumptions.
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    Cool. So sending me to the antipodes would cost less than a hundred bucks (Much less, because delta vee is much less than to orbit)? I see a beautiful future for tourism.

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I'd think the main cost is energy. That's why it's profitable to recycle alumimun, even though it's one of the commonest elements on our planet: Refining new aluminum takes lots of energy.
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The raw material is (or could be) water. Just add energy.

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But, liquefying LOX does not. All you need is the energy to cool it down to the boiling point, then to liquefy it. This is relatively small. Very large condensation plants can probably approach this.
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Energy is not free. The cheapest way currently AIUI is to make it from natural gas.

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That depends on what you mean by "cheapest".

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Economically cheapest to purchase.
IMO, we should go to nuclear for electricity generation, and hydrogen would be produced that way. But some believe that nuclear is evil.

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And many believe that it is not economically cheapest to purchase.