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Imagine a ribbon-like nanotube stretching from the Earth into outer space, and up and down which an elevator transports people and materials into space. The nanotube remains taut because of gravity and the spinning of the Earth--picture a ball being twirled around on the end of a rope.
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My concern would be, how are they going to deal with large objects that get in the way of the tube? The implications for story line are great though. Corinna
Posts: 17 | Registered: Jul 2002
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What are you talking about? How can anything get "in the way" of the tube? 'Tis the other way around, the lower portions of the tube would get in the way of low orbit objects.
Posts: 8322 | Registered: Aug 1999
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This was suggested by Arthur C. Clarke in The Fountains of Paradise.
If the carbon nanotubes can be made to function as described, and somehow manufactured to 62,000 miles vertical, I expect that this sort of thing would certainly be built.
But consider the implications. This thing extends to a very high geostationary orbit. It has to. That means things in low Earth orbit can never pass directly beneath it. Most of those things, like the Hubble Space Telescope and International Space Station, cannot change course to avoid the collision. At the same time, everything that orbits the Earth must cross the equator at some point.
Is it even possible to find a spot on the equator over which no LEO object will ever pass? Probably not.
So you would have to create "orbital corridors." All orbiting object would have to be placed in these corridors to avoid hitting the nanotube ribbons. Talk about a tough restriction!
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'Tis really not as big a problem as you seem to think. LEO objects can easily be retargeted if you have the ability to orbit small boosters to them, which is one of the capabilities that the Elevator will provide. In fact, with the ability to put up large amounts of material resources, the elevator will effectively put LEO and even High orbit items into the "user servicable" catagory, which means that you won't have to use disposable satillites for near orbit jobs, when they are in danger of deorbiting, you just send out a service team to correct the orbit (all near Earth orbits suffer from drag because of the upper atmosphere, which causes objects in those orbits to eventually infall).
Anyway, the elevator is really quite an old idea. It was first suggested in 1895 by a Russian scientist named Konstantin Tsiolkovsky (an important figure in space exploration).
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This concept came up in New Scientist magazine a while back. A number of objections were later raised in the letter pages. Posts: 286 | Registered: Jun 2002
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Yes, well until recent developments in materials science, areospace, geopolitics, energy generation and transmission, and any number of other areas, a space elevator was impossible for an inordinate number of reasons.
Amazingly, the space elevator would make high Earth orbit much easier to reach than low Earth orbit. Consider:
Objects in Low Earth Orbit travel at about 18,000 miles per hour, circling Earth every 90 minutes. Objects in geostationary orbit circle the Earth every 24 hours. At LEO altitude that's about 1,125 miles per hour. That's only 6% of the speed you need to stay in orbit! If you ride the space elevator to LEO altitude and step out you will drop like a rock!
The good news is that you won't be going fast enough to burn up. You could survive that fall with just a parachute.
If you really want to ride the space elevator to LEO, you need to take a rocket with you. When you step out, the rocket needs to give you the other 94% of the speed you need to put you in LEO.
quote: If you ride the space elevator to LEO altitude and step out you will drop like a rock!
The good news is that you won't be going fast enough to burn up. You could survive that fall with just a parachute.
I've given this a little thought...
I WOULD PAY A LOT OF MONEY TO DO THAT. So would lots of people.
It would certainly make a hell of a good SF story. THe author could invent lots of technology, such as "Jump suits," and etc. People would keep pushing the limits until somebody DID burn up. Then they'd improve the technology and get ablative suits, etc....
It wouldn't win a Hugo, but damn, it would be a fun story...
[This message has been edited by chad_parish (edited September 09, 2002).]
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You can just ride the elevator a bit further up than your target orbit, then jump off. You will drop nicely into an elliptical orbit that can be adjusted quite easily with a few correction burns. You don't need to get anything like 94% or even 50% of your orbital velocity from a rocket (in fact, you would want to go high enough that you would require a braking force at the perigee of the elliptical orbit, most of which could be provided by skipping off the atmosphere). True, this would be more complex than simply riding up to the GeoSnych station, but it would actually take less energy (for Low Earth Orbits, anyway). And to reach anywhere other than the Elevator stations, you would need to cut free and make corrective burns anyway.
The only orbits that wouldn't be substantially easier with an elevator would be east to west orbits. Since we don't even try to put things in east to west orbits anyway, I don't see that as a problem.
quote:. . . So it came to pass that a variety of foaming, inflatable, deployable systems were proposed - among them the famous General Electric MOOSE and the Space General FIRST. These gave the suited pilot the chance to step out into the void from a crippled craft, pull the ripcord, and manually cannonball or glide to the earth’s surface.
Strange but true, these are real proposals for the space program. Now that's what I call The Right Stuff!
quote:. . . Here is the ultimate adventure awaiting some millionaire thrill seeker. The FAA may not approve, but how about strapping your fanny to some surplus Russian SLBM or developing country space launcher. A quick boost to orbit, a few photo opportunities, then the challenging retrofire and that long free fall or paraglide back to the earth....
[This message has been edited by Doc Brown (edited September 11, 2002).]
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