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View Full Version : Space Elevators - For Real!



ToSeek
2002-Mar-27, 02:00 PM
The Space Elevator Comes Closer To Reality (http://www.space.com/businesstechnology/technology/space_elevator_020327-1.html)

Azpod
2002-Mar-27, 05:36 PM
On 2002-03-27 09:00, ToSeek wrote:
The Space Elevator Comes Closer To Reality (http://www.space.com/businesstechnology/technology/space_elevator_020327-1.html)



I still love the concept but one nagging question remains: what do we do about the fact that everything in low Earth orbit, from paint flakes to the ISS, whiz by the cable at incredible speeds? One hit from any of those would easily shear the cable, no matter what is made of. I don't see us mothballing the shuttle and deorbiting all of the large number of objects in low Earth orbit anytime soon.

Hat Monster
2002-Mar-29, 06:31 PM
Hasn't BA got an article saying this is impossible?

There'd be massive tides in the cable, and each point in the cable will want to orbit at it's own speed.

Phobos
2002-Mar-31, 06:29 PM
On 2002-03-29 13:31, Hat Monster wrote:
Hasn't BA got an article saying this is impossible?

There'd be massive tides in the cable, and each point in the cable will want to orbit at it's own speed.



I doubt it - if that were so the same could apply to all objects. If a cable of 1 metre length can withstand these forces, then a cable of any longer length should be OK. I am personally surprised that cables based on nanotudes are expected to be able to withstand their own gravitational weight - that to me is astonishing.

Jeff

David Hall
2002-Apr-01, 03:10 AM
I personally feel we can trust the physicists calculations about whether a space elevator is possible. If they say that these new materials are strong enough to handle the load, then they probably are.

However, I think they are vastly underestimating the difficulties of actually putting one of these babies up. In addition to the dangers of orbiting debris and generating electrical current (I suppose this could be used as a power source?), I think just simply stringing it up would be terribly difficult. I remember the disasters of the shuttle tether experiments, and those were just a few hundred meters long, so a thread measuring in thousands of kilometers would be magnitudes greater in difficulty.

I think the biggest problem would be in laying the first thread. Especially I see a problem in getting it through the atmosphere. Stringing down from above wouldn't be too hard until you reach the upper levels of the atmosphere, but then I think it would become impossible to control the end from there to the bottom. I suppose you could try to "catch" the end and guide it down, but in that case you are tugging on a 22,000km+ long thread, which can't be easy to maneuver, especially considering winds and weather.

Or, you could try to string it from the bottom up, but how? You'd need to launch a rocket with a quickly unravelling thread snaking up from behind it. And it has to be strong enough and long enough to reach geosynchrous orbit, unless you could control it well enough in low-earth orbit to splice 2 ends together. Sounds like an engineering nightmare to me,

Of course, if you can get that initial strand into place, then the rest of the construction would be relatively easy.

But remember, I'm no engineer, so take this all with a grain of salt. Maybe they've got these things figured out too. I just think that reality is bound to surprise them when/if they actually try it.