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Riding The Space Elevator
savas was one of the folks who sent in the story concerning the possiblities of a space elevator in 50 years time. They make good sense, especially if we are committed to doing something more than the current small commitment to space.
The thing would fly perfectly well without an anchor; it's just a matter of putting it in a stable orbit with one end of the cable near the surface. It could be kept out of the lower atmosphere, and if needed a small difference from geosynchronous orbit would allow it to circle the equator slowly. One could also put aerodynamic forces to good use in adjusting the thing down or up.
Anchoring it to the earth would only be necessary if more downward force is needed, but it seems to me that down-force is to be avoided. Keeping the thing up with minimal additional tension in the cable would be better.
One should also look at what happens if the cable breaks. The greater the tension, the greater the energy released, and the larger the perturbation on the circular orbit. If the thing can be kept up without a lot of external force (i.e. yanking on the string), it's probably more stable.
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Hairy Potter, woefully clueless American, wrote:
Looking at the equatorial slice, you have Central and the northern part of South America. That's close to the US, but the only country in that area that sounds somewhat reasaonable is Venezuela. I think they're stable, and at least somewhat technically clueful.
Hairy, you may want to read the newspapers once in a freaking while.
First of all, you're completely wrong about South America, which has come a long way in the last twenty years. Not only have most countries turned from military dictatorships or nationalistic juntas toward multiparty democracies, most are fully industrialized and modern. Brazil even has its own nascent space industry with a launch site at Alcantara, and an aeronautical industrial center calling itself Space Valley.
Brazil has skyscrapers, subways, and even computers. (What, did you think they lived in mud huts?!)
Venezuela, on the other hand, has recently turned into as close to a rogue state as you can get and not actually be one. The President has endured the censure of the United Nations, the Organziation of American States, and others, and has deliberately met with pariah leaders like Moammar Khadafy and Saddam Hussein. Venezuela is heavily Western-invested due to its oil industry, but many companies are reconsidering its long-term political stability.
A shame there aren't more, as close to the US is a major plus, since American will probablly pay for most of it.
Why would you assume that Americans will pay for most of it? Why would you assume that taxpayers will pay for most of it? More likely it will be built by an international consortium supported by investors and ultimately funded by the companies that buy its services. (Look at the Chunnel, or any modern major toll bridge, for examples.) Of course, that's assuming that stick-in-the-mud American industry is interested, which they may not be. (Our economy goes through phases during which it will throw money any and all innovation, no matter how inane, and during which the very word innovation is considered poison. Look at high-tech from 1999 to 2000 for an example.)
Going East, we get to Africa. Enough said there, I wouldn't invest a significant amount in Africa until it gets more stable.
Africa's a pretty big place, kiddo. Some parts are stable, others are not. That said, the industrialization there in 2000 isn't that convenient for a space industry. That could change, though.
Further East is India and Sri Lanka. India would certainly be a possibility, they have high tech, they speak English.
What kind of incompetent school did you go to, that you believe speaking English is a pre-requisite for mastering high technology? India is not only a land of breathtaking scenery mixed with breathtaking poverty, it is also a land that has made a leap to the cutting edge of high technology. The computer industry is supplied by a steady stream of incredibly smart and motivated people from India, many of which I've been proud to work with.
While Singapore has a harsh dictatorship, it is stable and high tech. Indonesia and the Phillipines have too many trouble.
Singapore's Asian-style strongman semi-democracy isn't what I would call open and free, but I wouldn't call it a dictatorship either.
Basically, I think you have a view of the world that is informed mainly by 30-second sound bites on CNN Headline News. Get out of the house once in a while. Talk to people who look different from you. Read a book or a newspaper. The rest of the world is a little more interesting and capable than you think -- and not all decisions about the future are made in the United States.
Good grief.
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It has to be very near the equator, which really limits the places. You want to have a stable, reasonably high tech place that you can get to easily. I mean, you don't want to spend trillions of dollars to build it, and have it be destroyed in an uprising.
Looking at the equatorial slice, you have Central and the northern part of South America. That's close to the US, but the only country in that area that sounds somewhat reasaonable is Venezuela. I think they're stable, and at least somewhat technically clueful. A shame there aren't more, as close to the US is a major plus, since American will probablly pay for most of it.
Going East, we get to Africa. Enough said there, I wouldn't invest a significant amount in Africa until it gets more stable.
Further East is India and Sri Lanka. India would certainly be a possibility, they have high tech, they speak English.
Still further East is Singapore, Indonesia and the Phillipines. Shades of the Cryptonimicon. While Singapore has a harsh dictatorship, it is stable and high tech. Indonesia and the Phillipines have too many trouble.
Counting the votes, it looks like Singapore is it, which is a shame since they're so far from the US. Oh well, maybe the Asian tiger will rise again.
Strong data typing is for those with weak minds.
Strong data typing is for those with weak minds.
Why does "riding the space elevator" sound like something Kirk would say to Spock (or "Bones") after visiting The Planet Of Scantily Clad Green Women?
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I was a participant in the Space Elevator workshop that led to this news item. I would like to make several comments on space elevator design:
1) A ground to synchronous orbit (35,000 km high) elevator is often discussed, but such a design is neither necessary nor economic.
A segmented elevator cable in earth orbit plus
orbit mechanics allows you to get around with only 1/7 of the height in actual cable segments. You coast between cable segments.
A tower from the ground several tens of km tall
saves you most of the losses that a rocket like
the shuttle sees from trajectory inefficiency and atmospheric drag. You simply launch from the top of the tower.
2) A real space elevator design will have multiple redundant cables because natural meteoroids and manmade orbital debris will occasionally run into the cable sections. The cables will be cross-connected so that the loads will be routed around any break (kind of like packet routing for the internet). You will have robot 'spiders' that will carry replacment spools of cables and be able to replace broken sections. This maintenance is like painting bridges continuously to keep them from rusting.
3) Existing high strength carbon fiber (1 million psi strength) is sufficient for economically rational space elevators. Carbon nanotubes are
strong enough for a 35,000 km space elevator,
but they would also make possible ultra-light rockets that would eliminate the cost justification for such a large elevator.
Daniel
Not long after construction begins, all the workers will begin speaking different languages and the project will be abandoned. It's happened before...
"At the moment, Sri Lanka lies between 6 and 10 degrees north" Do they intend to move it or just wait till precession moves the equator closer?
Doesn't pass through India or the Phillipines.
Are the close enough? I don't know enough physics, but the article makes it sound like if you get too far away problems arise - both with the orbit and with atmospheric events like cyclones, etc. Both India and the Phillipines are known to have cyclones and typhoons.
You also miss some important countries. Most importantly, Brazil (equatorial rain forest, anyone?)
Brazil is known as "the perpetual country of the future". Today, the future looks closer than ever for Brazil. Brazil's democracy is solidifying to the point where today one of Brazil's foreign policy goals is furthering the cause of democracy in other S. American countries (Peru is a current target). While the financial system is still modernizing (witness the 1999 currency devaluation), Brazil is on it's way to becoming a low-inflation, high-growth economy.
While Brazil is still decidedly "low-tech", it is modernizing quickly, in part to due it's large population, in part due to it's realative wealth compared to other third world nations.
Also: as others point out, by the time it becomes feasible to build the elevator, Indonesia and parts of Africa may become much more stable, which may make them more attractive choices (especially Indonesia - after a few years of solid democracy, all the things I said about Brazil may be valid for Indonesia). Moreover Singapore has a downside... is there enough space to build an elevator there?
2: Its not Impossible With the stopping voltage, and some power taps into the upper atmospheres plasma, you could effectively control the location of the cable. Additionally, you coulduse this to help control tension and compression in the cable. Flexibility isnt too big a problem, most things are pretty flexible when theyre 144000km long. Think of it this way, take a foot long peice of structural steel and try to bend it, doesnt work too well. Take that same peice of steel and make it 110 stories tall, and see how much it bends in a high wind or an earthquake.
3: Would you like to back this claim up with some actual facts?
4:If this is true, then why didnt the soviets shoot down our spy satellites? Why dont the iraquis? why dont we shoot down the russians?clearly we have the capability.National territory only goes up so far, something like 160 km, since there will be a tower 50km of that way, there isnt too much room for movement, and even then, why would you want to do it?