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Space Elevator Update
TheMadReaper writes "The 2005 edition of the Space Exploration Conference in Albuquerque, NM came to a conclusion earlier this week. A large fraction of the conference was devoted to the Space Elevator. Surprisingly, there hasn't been much news coverage of this conference, perhaps because it doesn't have Space Elevator in its name. The most interesting fact I got from the conference is that money is really starting to exist in the space elevator world mainly thanks to the work of Dr. Bradley Edwards at ISR and at Carbon Designs, Inc. The strong nanotube talk was also more promising than last year."
Operating costs estimated at 100 kg/lb, ready in 15 years at most optimistic.
Kilograms per pound? What is that?
Now I know, anything is possible with technology. Science fiction of the 50's is science reality of today. But let's stop the conversation of "is it possible" with that. The question of if the Space Elevator CAN be made seems irrelevant to me.
When it comes to this whole Space Elevator business, the relevant question in my opinion is "would we WANT to make something like that?" To me, it's a novelty idea and nothing more. If people want to get serious about space travel, we need to invest more into the building of in-orbit construction yards (IMHO). Once we get the infrastructure in space to produce the vehicles, we'll find that occasional trips to the "Drydock" from Earth to supply it with raw materials will be far more practical than some 21,700+ mile long elevator reaching into the sky.
-Vendal Thornheart
As long as youre wearing a spacesuit theres no reason why you couldn't base jump off to escape... ...Or for the fainter of heart - atmospheric bungee jumping!
Man what a rush.
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beware he who would deny you access to information, for in his mind he dreams himself your master
The surviving fragments of an orbital tether would not have the requisite mass to produce the sort of wave disturbances you postulate. Actually, from most accounts, the worst health hazard resulting from a broken orbital tether would be small fragments of nanotube floating about in the atmosphere, eventually drifting to ground level and getting lodged in the lungs (as it turns out, carbon nanotubes are about the same size as asbestos fibers...perfect for getting lodged in the lungs).
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~ |rip/\/\aster /\/\onkey
A space elevator, or beanstalk, has two big problems for construction: 1) materials that are strong enough, and 2) getting it to stay up.
The first we're getting close to being able to handle. The second is just a matter of having a counterweight that balances the 22,500 miles of cable from the equator (more on that later) to the top. Without the counterweight, the ground end drags it down.
That means that we really need to build this sucker from the middle out: extend equal masses out and in (or up and down, if you prefer) from geosynchronous orbit. That's a very expensive proposition. Whether it's cheaper to ship carbon for nanotubes up or go and fetch some carbonaceous asteroids down to our orbit I'll leave as an exercise for the reader.
A poster above was concerned about the terrorist target of something like this. The one consolation in this one is that you can't build it on US or European soil: it needs to be at the equator. At least one SF author (I forget which) posited an elevator whose ground-level terminus was an upside-down Y to two islands straddling the equator some hundreds of miles apart. Not the silliest thing I've ever read, but I'm not sure it makes much sense. Tethering one end down will be tricky enough.
So it won't be Imperialist America that's building it... but that's not to say it won't have protestors. It'll cast a shadow pretty much across the entire planet. It will likely change weather patterns in the region.
It will create the most valuable real estate in the world.
It's going to end up in some place where technology and resources are accessible: Brazil, Equador, Congo, Somalia, The Maldives, Indonesia, Malaysia, or some Pacific Island are all candidates, my money is on a spot just south of Singapore -- there's enough high-tech industrial nations close enough to justify it there. Brazil is my second guess.
And who knows, maybe we'll find Saddam building WMDs up there. (obligatory Funny whoring)
Design for Use, not Construction!
"If you're stuck high and above, you might have the space shuttle come and rescue you."
No.
At altitudes the shuttle can reach, the relative velocity between the shuttle and the elevator would be too great for a transfer.
Also, the shuttle can reach a few hundred kilometers. Not sure specifically what the limit is, but it's under a thousand kilometers. A space elevator has to go all the way up to geosynchronous orbit, which is 35786 km. You're out of reach for most of the journey.
It wouldn't be that hard (relative to the cost of the project anyway) to have an escape pod in elevator cars that have to carry humans. That could carry passangers back to earth, as they'd be in free fall for the most part.
I rarely criticize things I don't care about.
Look the longest Nanotube is about 2 mm. (I've seen them and know the student making them.) Nanotube fibers are made but they are tough to do. The amount of MWNT (the easy stuff!) made in the US is small. There is no way to make a massive amount of the stuff. Certainly not the amount needed for an 'elevator'. Now let's consider the minor factoid that you will have to drop something heavier than you are lifting. (Or at least of similar mass.) I have single word that this space elevator project does not consider - physics
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Two main points are:
Geostationary orbit is a long way up.
We don't know yet if carbon nanotubes have the strength require to be able to handle their own mass over such a distance - or half it if you have an asteroid keeping station at the other end.
Call back when we have the technology to bridge from Singapore to Mexico City in a single span - we'll be a small fraction of the way there.
I see this whole concept as just being another aspect of people getting too influenced by Biblical sound bites - they want to build a tower of Bable for the sake of it, while similar ludrous schemes for launch like building a mass driver circling the equator would be orders of magnitude cheaper. Keep your religeon and your science seperate guys. People would argue this came from SF, from people that have heard of geostationary orbit but don't have a clue, but it gets rooted in our heads from Sunday School and the Bable story.
It seems likely that the estimates of 12 years are a little optimistic for something of this scale, but I would certainly like to be wrong on that count. However, if we spend 5 billion dollars on this and we end up developing the technology to cheaply produce super-strong cables out of carbon nanotubes, I say it is money well spent, even if there is no space elevator.
If it works, a space elevator is THE best way to get things in and out of orbit. Also, I am sure you realize it, but your bridge analogy is specious at best. Building long bridges and tall elevators are not comprable projects.