:: Space Elevators
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> What happened to the ladder to heaven we were going to
Tower of Babel, did you say? :-)
Presumably you mean the "beanstalk" / space elevator / ...
It is almost practical now for limiting values of practical.
ie the "taper" rate depends on the strength of the material
used. The best material available now COULD (probably) be
used to build one, but the taper rate is ugly. If the
material scientist boyos keep chugging along at current
rates it will keep on getting more practical and start to
approach downright compelling in a few decades. (When they
start *seriously* talking about building a single span
suspension bridge across the Straits of Gibralta it's bean
stalk time. Materials requirements are roughly equal.
This version cheats - only 5000 metre spans (!)
Beanstalks have other issues apart from pure implementation
practicality. You have to build them from the top down or
top down with fly in or similar. Having a lot better/cheaper
access to space (chicken and egg) and will power to do it
and need to do it would help muchly. If you can source some
materials from 'out there' it saves hauling it from 'down
here' which can help. The idea of making this sort of thing
from material gained from 'out there' is liable to rather
add to the delays.
If you break one of these, depending where you break it. it
will want to wrap itself all the way round the world a
number of times. That could be an extremely bad thing to be
anywhere near, quite apart from what the shareholders and
insurers are liable to say. If you do build one then placing
a nuke or other suitable device on board becomes the #1
dream of every 911_upstager_wannabee going. Trying to fly
anthing, however innocuous, anywhere near it would guarantee
flight 007 / USS Vinciennes type results instantly. Deciding
who is "allowed" to build something that so dominates so
many aspects of earth and who allows them to will be
interesting questions. If there are N of these (N >1) then
you really really really don't want even 1 of them to fall
down! Mayhaps (and I just made this up) by making them
resonant and slightly off equator you MAY be able to make
them mutually non interfering in the case of a disaster.
(Resonant beanstalks have been proposed for eg Mars to allow
them to dodge the moons which are below the beanstalks
necessary minimum height.)(Or is that only one of the
moons - too lazy / forget - look it up yourself). A static
beanstalk must have its feet on the equator but perhaps a
dynamically oscillating oen can be offset slightly. Perhaps.
Kim Stanley Robinson is his stunningly marvellous
Red/Green/Blue Mars fiction trilogy did a fair job of
discussing the making and breaking of beanstalks.
Many refs below.
Here's one on 'some world somewhere'.
A fw people [tm] are interested:
NASA ! :-)
See also: www.piclist.com/techref/index.htm?key=space+elevators
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