

Should we give up on the dream of space elevators? - dnetesn
http://www.bbc.com/future/story/20150211-space-elevators-a-lift-too-far

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NeutronBoy
> _The Obayashi Corporation, one of Japan’s five big construction companies,
> last year published plans for a more robust space elevator carrying robotic
> cars powered by maglev motors similar to those used on high speed rail
> lines. These would carry humans making the required tether strength greater.
> Their design would cost $100bn, with transport costs down to $50-100 a
> kilogram._

That seems... incredibly cheap for a space elevator. Are they saying their
design would cost $100bn total, or is that for the car only?

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Marcus10110
I would have guessed closer to the world's GDP, maybe a few orders of
magnitude more.

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gremlinsinc
What about instead of space elevator some sort of re-usable space launcher -
i.e. a HUGE tunnel like contraption that basically propells a vehicle up and
out of atmosphere without rockets but something else... - - think like a large
hydrolic delivery system that goes x amount of miles from upper atmosphere and
vehicle launches at whatever the velocity is to break out of atmosphere ? (I'm
no rocket scientist obviously)

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noir_lord
No.

[http://en.wikipedia.org/wiki/Betteridge%27s_law_of_headlines](http://en.wikipedia.org/wiki/Betteridge%27s_law_of_headlines)

Why give up on something because we can't do it _right now_.

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jack9
Yes. Because it's fundamentally flawed. You will not beat physics because you
wish it. It will always take the same (relative) amount of power to escape
earth velocity. Shunting some of the friction to entropy on substances (wear
and tear) in sizes/lengths/stresses that are affected by atmosphere and space
junk, leads to a more complicated and less reliable mechanism for transport.
You STILL have to fight gravity and air resistance with an elevator. It's
bought you NOTHING of value to build.

~~~
noir_lord
> It will always take the same (relative) amount of power to escape earth
> velocity.

Not really, most of the energy in a rocket launch is used to push the rocket
fuel higher so it can be burnt to push the remaining rocket fuel higher.

If we could build a space elevator then the energy used to get a mass into
space would be considerably lower since electric motors are much more
efficient at lifting loads than rocket engines (and that assumes a mechanical
method of lifting not some kind of mag lift system).

