Instead of asking these questions here you should visit the site and you'll find the information. That's why I posted the site. Nevertheless, I'll try to answer some of these questions.
The Space Elevator is basically a very long cable that stretches from a space station in geosynchronous orbit to the ground. The point of ground contact must be very close to the equator, of course, and that limits where it can be setup.
Although... there has been talk of using some fancy engineering to make 'diagonal' cables from temperate lattitudes meet several hundred miles up and then connect to the single cable coming from the large station in geosynchronous orbit. Once you got it setup it would work as well as the single cable system. The problem is in setting it up!
There are several reasons this is an easier way into orbit than rockets or other launch vehicles. The first is simply that you don't have to push so hard to go up! Heating thousands of tons of gas to very high temperatures by combustion so they will bLast you upward in the process is very inefficient, not to mention
dangerous. With the space elevator you could have an electric motor more-or-less like those on current elevators in high-rise buildings. Or perhaps a 'pneumatic tube' type system with the air being pumped up to the station serving to propel the elevator as well!
Anyway, not having to gain speed by 'throwing' stuff away from yourself at high speed is both more efficient and safer. If the elevator cars are 'external' to the cable then you also have to deal with air resistance but this is better with the cable than with rockets as well. You also don't have to go for super-sonic speed right away. Obviously it will be a long ride into orbit if the whole trip is at standard elevator speeds
but it's best not to go more than a few hundred miles an hour for the first 50,000 feet or so. After that you can go thousands of miles an hour with no major air resistance problems. Not having to fight the atmosphere or design for the heating from friction makes the elevator cars much cheaper than rocket vehicles. If the elevator will be inside the cable (more difficult but we'll probably do that eventually) then you could evacuate the air and use the 'pneumatic tube' effect as I mentioned before.
The possible accidents and problems are many of course. If the cable breaks somewhere up in orbit and loses 'equilibrium' so that it comes down, it will cause damage across hundreds or thousands of miles of terrain. It's got to be made of incredibly strong materials so it will probably destroy anything it comes down on, crashing at orbital speeds. If the whole cable comes down it would wrap almost all the way around the earth!
The 737 question is not such a problem as you might think. A modern jet airliner is basically a huge aluminum ballon. It's very fragile and the cable is very strong. An airliner would be sliced up if it hit the cable but probably do little damage. More dangerous would be a hit on the ground link where an explosion and fire might damage the anchorage. I think the elevator 'cars' will be far more vulnerable than the cable itself. They cannot be heavily armored without increasing costs quite a bit. They are rather similar to jet airliners in that respect! A small bomb could punch a hole in one when it's part way up and expose everyone inside to the vacuum of space. This could be at least as tricky to guard against as it is for airlines since explosives have become so high-tech and difficult to detect.
The station in orbit is pretty safe actually. You can use it as a launching point for ships headed out from earth and they will get a good boost, but the station itself will not 'come down' any more readily than a station without a cable. Obviously, if something grabs the cable and
pulls it out of orbit you've got troubles. But that would take a lot of force. It's got to be a large station to anchor the cable and make the 'center of gravity' of the whole assembly rest in orbit. Hundreds of thousands, if not millions, of tons. There has even been talk of trying to capture an asteroid and use it as the counter-weight. That's a whole other mega-engineering project. We can worry about that after we've got at least one working cable... In the meantime we'll probably mine the moon for the bulk of the station material.
The issues of who would get to use it, and what it would be used for, are actually more serious than the engineering questions. It looks like we've got a material that can be strong enough to make the cable (Carbon nano-tubes). Everything else is known technology. But once it is built what effect will it have on the world? That's a very different problem than the technology.
[ October 09, 2002, 05:06: Message edited by: Baron Munchausen ]
Re: OT: About Space Elevators
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