http://en.wikipedia.org/wiki/Launch_loop
http://en.wikipedia.org/wiki/Space_fountain

What about these guys?  I know you've mentioned them before.

I prefer these to the space elevator, largely because I've READ KSR's
description of what happens when one fails...

Mike H.

On Mon, Jul 28, 2008 at 6:52 AM, Apptech <apptech@paradise.net.nz> wrote:
>> What happened to the ladder to heaven we were going to
>> build?
>
> 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 (!)
>    http://www.opacengineers.com/index.php?menu=projectsheet,Gibraltar
>
> 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.
>
>
>        Russell
>
> Here's one on 'some world somewhere'.
> Nice picture.
>
>        http://www.blog.speculist.com/archives/06_SpaceElevator.jpeg
>
> A fw people [tm] are interested:
>
>        http://www.spaceelevator.com/
>
>        http://www.spaceelevatorblog.com/
>
>        http://www.liftport.com/
>
>        http://en.wikipedia.org/wiki/Space_elevator
>
>        http://www.space.com/businesstechnology/technology/space_elevator_020327-1.html
>
> NASA ! :-)
>
>        http://science.nasa.gov/headlines/y2000/ast07sep_1.htm
>
>        http://www.spaceward.org/elevator2010
>
>
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