Posted on 02/21/2005 4:38:48 AM PST by nuke rocketeer
Wasn't this same concept proposed in the book "Red Mars" by Kim Stanley Robinson back in '93?
By definition, a geostationary orbit is at 21,000 miles over the equator, moving at 6550 mph.
So, I take back what I said before -- if you took the elevator to exactly this height and stepped out the door you'd stay in orbit.
But any lower, you'd fall to Earth. Any higher, you'd fly away.
As I understand it, things climbing the elevator would basically be borrowing momentum from the earth's angular momentum, provided through the tension in the "cable". The physics of this idea are well understood, it just the implementation details that are a bit fuzzy yet.
Yes they would. But you can see how this would put a sideways force on the cable, bending it into a large "C" (and pulling the end of the cable down from 62,000 miles to a lower altitude).
Granted, the more the tension, the less sideways movement.
Charlie and the Great Glass Elevator
Watch out for the Vermicius Knids!!
"So, I take back what I said before -- if you took the elevator to exactly this height and stepped out the door you'd stay in orbit.
But any lower, you'd fall to Earth. Any higher, you'd fly away."
Actually, at lower heights, depending on just how low and just how fast you were at that point, you might just fall into a lower, faster (in angular terms) earth orbit. At a higher point you'd fly off into a higher, slower (in angular terms) orbit.
Oh, I don't doubt that the cable would not be perfectly straight, but I think the forces from lifting a load would be fairly small compared to the overall mass of the thing, and compared to the loads from wind friction and such. I'm sure these guys have considered these factors.
If the cable used for the elevator were conductive, would it not produce a current of electricity simply because it is passing through the earth's magnetic field? I would think a HUGE current flow would be generated.
Cargo doesn't care how long it takes. Besides, even if we're talking about people, I think astronauts are used to sitting around for extended periods of time.
Look, if we can perceive of technology capable of 200-300 mile high elevator, then why not look to develop technology similar to that from Star Trek--the transporter, or the shuttles--which could get a person from the ground to space in mere minutes? After all, if we're going to fantasize about future modes of transportation, then let's really use our imagination.
Apples and oranges. The space elevator is an engineering challenge. The science is already pretty well established. Your other ideas are scientific challenges, which make them far greater hurdles. You have to fully understand the science first, before you can start engineering something.
Here's one for you guys. All the talk above in the thread is about what lateral speed the object taken up on the elevator achieves.
What about Earth itself? This is the equivalent of a spinning ice skater whose arms are held close to the body and then then extended outward. It slows the spin.
:)
"Ground floor perfumery, stationery and leather goods, wigs and haberdashery, kitchenware and food, going up!"
I don't remember. I do know that Niven and Pournelle have proposed it in several of their books.
One wonders what the "jet stream" will have to say about all this..
This sounds like multi-level marketing to me..
Calling all Amway distributors.!. the ultimate scam has finally arrived..
NOTE....
Leftist "scientists" <<-- are Moe, Larry and Curly with governmental support..
It's actually worse than that, because there would presumably be a constant stream of stuff being put into orbit, gaining momentum from the Earth's angular momentum. Over a long enough period this might actually add up enough to affect the earth's rotational speed, although the Earth has an awful lot of angular momentum, given its enormous mass.
Nanotubes are called that because of diameter not length. That said, current production is only a few microns long. However, we are working on joining them end-to-end to make cables. They have enough tensile strength to make the elevator feasible. As for power and the angular momentum questions, remember that we can generate ENORMOUS quantities of power by lowering asteroidal mass, e.g., mined platinum, DOWN the cable assembly (its not a single cable, but a group of joined cables). Imagine a turbine with a "head" of 22000 miles and you get the picture.
Don't reinvent the wheel--this has all been solved long ago. See Genesis 28:10-16.
The first objection I can see is how any such device would interfer with airline travel, not to mention creating a really big target for would-be terrorists.
When I wrote about the shuttles, I was not talking about a vehicle that launches like a rocket. Why not design a VTOL vehicle that can acheive multiple-mach speeds, and take off and land on its own power, plus a serious cargo load. How is that any more outlandish than a 200-mile high elevator?
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