
Race on to build world's first space elevator  - ryanwaggoner
http://www.news.com.au/technology/story/0,25642,24662622-5014239,00.html
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mkn
I've always wondered why, if you have a material sufficiently strong to build
a space elevator, you don't just use it to wind composite fuel tanks for
conventional rockets? At 150 times the tensile strength of steel, for example,
you could make a pressure vessel that holds 150 times the pressure that you
can with steel. Taking the densities as similar (sigma/rho is the relevant
parameter) that should make pressure-fed rockets not just viable, but hugely
preferable to turbo-pump-fed systems. It seems like you'd recoup your capital
outlay much more quickly, even if you did (eventually) use more material to
launch an equivalent mass of payloads.

For reference, in Engines of Creation (iirc), Drexler outlines a personal
launch vehicle that weighed ~100 lbs and could lift a single occupant to leo
with one stage. I suspect that the guys that finally do build a space elevator
are really just going to end up with a nice place from which to watch personal
spacecraft launches.

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nazgulnarsil
I'm very happy about the fact that this is inevitable. The first nation to
build it will have an order of magnitude if not more of an advantage when it
comes to space travel costs.

Not being stuck at the bottom of a deep well is going to be a game changer.

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hugh
I'm still not convinced that it's possible to make the kind of super-long,
defect-free nanotube cables that are going to be required. I'll be very happy
if I'm proven wrong, but I certainly wouldn't say it was inevitable.

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electromagnetic
You should watch the new episode of Mythbusters called Motorcycle Flip, as the
side myth in it is testing if someone can actually escape from jail like some
newspapers state the 'facts' like using human hair, bedsheets and toilet
paper. As all three get proved plausible, it shows what can be turned into a
cable.

When someone can make a rope out of single ply perforated (the easy-rip kind)
of toilet paper, I think someone will find a way to make a cable out of
nanotubes.

From what I've read of nanotubes, you might not even need an adhesive to hold
the cable together as they have high levels of van der Waals force. If you
simply splice all the ends together it's possible you'd have the worlds
strongest material held together by the universes everlasting and powerful
adhesive.

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geuis
If you're interested in some commercial companies currently working on this,
check out the LiftPort Group. <http://liftport.com>

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nsrivast
I wonder why Perth? 2000 miles south of Hawaii makes sense since it's near the
equator to maximize centrifugal force and tangential velocity during launch,
but why Perth?

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steveplace
It is more economically feasible to transport materials to Perth.

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tocomment
Is there anywhere to read about the physics of this for a mechanical dummy?

Specifically I'm wondering, wouldn't the counterweight be pulled toward earth
every time we use the elevator? Would we have to continually boost it?

Does the counterweight have to be in a geosync orbit, or the center of mass?
If the latter, what keeps the counter weight in geosync?

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fhars
What are the failure modes of this technology? It appeals mosly to SF fans,
and every SF fan who has read the Ringworld novels will think of cities
crumbled to dust by flailing nanowires...

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wlievens
The upper half would fly off, and the lower part would burn up in the
atmosphere. I think.

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jsmcgd
I don't think it would burn up because its relative motion to the atmosphere
will be zero apart from a relatively small vertical acceleration due to
gravity. It would most likely come straight down on top of its base.

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vlad
Proof of concept at VC pitch meeting: Willy Wonka movie.

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lyime
I have one word. Why?

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Herring
Well there's only one reason for a male to risk death, radiation damage, bone
loss, etc & it's not the rocks.

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vaksel
before they make a space elevator, they need to build a proper space station.
The current one is tiny. I want something the size of an oil tanker.

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snprbob86
but it would be much cheaper to build a cruise liner of a space station if we
had a space elevator

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ram1024
space elevators are at least 50 years away...

we haven't even been back to the moon yet. let's be realistic

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stcredzero
Space elevators are just one way of avoiding the near exponential nastiness of
the rocket equation. We currently have the ability to construct compressive
towers that extend beyond the atmosphere. Build several of these, and park an
electromagnetic accelerator on top, and you have something that gives you the
same economics as the space elevator for a comparable price. The big problem
with this scheme: building it would be politically impossible.

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nazgulnarsil
are you talking about this?
<http://arxiv.org/ftp/physics/papers/0701/0701093.pdf>

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stcredzero
Not just that. There are more recent calculations involving modern carbon
composites somewhere in Google Groups.

