Posted on 03/27/2002 9:32:03 AM PST by RightWhale
That's putting it mildly. One could say (just as accurately) the same thing about the asteroid that wiped out the dinosaurs.
However every part of this structure below the geostationary point IS NOT in orbit and will be falling toward earth. Unless some tremendous thrust is constantly applied by the endpoint to lift the whole thing up, it will fall back to earth.
Secondly, the act of transporting cargo up to the geostationary point is not free either. The cargo capsule will have to attain orbital velocity by the time it reaches the endpoint. Either the structure will impart energy to the capsule or the capsule will generate the velocity itself.
Someone please explain in terms of orbital physics how this thing can work. I just don't believe it.
When ever there is a thunderstorm near the anchor point (can you say lightening rod?) the station in orbit would make some excellent light. But would it be a glow or more like a flash cube? Could they keep some sort of large capacitor on board and charge it from the lightening? Then use this capacitor to flash shuttles to the Moon or Mars?
What a coincidence. IIRC, the fictional chief engineer who built the space elevator in Clarke's book also built the Gibraltar Bridge, which leads me to believe that the claim in this story that a space elevator is easily within our reach for a paltry $10 billion, with all due respect, is a load of manure.
How can you get a length of cable that long? How is that going to be easier than using cold fusion to fly your anti-gravity UFO up there anyway?
Skyhooks aren't "getting something for nothing", the energy lost by boosting payloads "up and out" is balanced by the energy gained by braking payloads coming "in and down".
Yes the endpoint would be in geostationary orbit, and perhaps one can visiualize hanging a very long string off it or somesuch. But you can't do that for free.
No, the "endpoint" is not in "geostationary orbit", the end point is BEYOND geostationary orbit. Read the article again -- the Space Elevator would be 62,000 miles tall -- geostationary orbit is only 21,700 miles up.
However every part of this structure below the geostationary point IS NOT in orbit and will be falling toward earth.
Unless some tremendous thrust is constantly applied by the endpoint to lift the whole thing up, it will fall back to earth.
[snip]
Someone please explain in terms of orbital physics how this thing can work. I just don't believe it.
The article itself explained it:
For a space elevator to function, a cable with one end attached to the Earth's surface stretches upwards, reaching beyond geosynchronous orbit, at 21,700 miles (35,000-kilometer altitude). After that, simple physics takes charge.The portion above geosynchronous orbit (which would normally want to go flinging out into space) pulls in an equal and opposite direction from the portion below geosynchronous orbit (which would normally want to go falling down to the surface).The competing forces of gravity at the lower end and outward centripetal acceleration at the farther end keep the cable under tension.
In short, tidal effects keep it balanced.
Secondly, the act of transporting cargo up to the geostationary point is not free either. The cargo capsule will have to attain orbital velocity by the time it reaches the endpoint. Either the structure will impart energy to the capsule or the capsule will generate the velocity itself.
No one said it would be "free". Energy would have to be put into the system via electric motors and such to do the lifting. But the energy cost to raise a payload to orbit that way would be *FAR* less than the incredibly wasteful and expensive method of blasting them into space on pillars of fire, as we're currently doing. The last figures I've seen amount to literally pennies per pound of payload (not counting the cost of construction of the "elevator" itself, of course).
Yes, there will be the weight of the entire cable below the geosynch point to be borne (with the higher portions subjected to less gravity, approaching zero.) This can be counterbalanced by extending the cable well beyond the geosynch point, which will generate centrifugal force due to the earth's rotation.
I can explain to engineers why their floating rig does not have the weight of the steel casing anymore after it has been cemented in (yea, this has been explained to several) but so can a Rough Neck.
I and others had to explain why it was not a good idea to pump fluid into a live gas well and then pump it out past the BOP. Shake a Coke Bottle and then open it and you will know why.
This is why I like the lightening rod theory with the attached night light.
I must have missed the post in which I said it would.
It would cause many billions of dollars in property damage and loss of life. Not to mention the fact that you'd no longer be allowed to have any satellites in earth orbit if you built such a thing.
It's technologically neat, and can probably be built from an engineering standpoint, but I have serious doubts about its practicality.
To be determined by experiment and computer simulation.
Only two things are certain. Whatever can go wrong will go wrong. And go wrong in the worst of all possible ways.
I say this somewhat tongue in cheek, since the WTC surived long enough that everyone who could evacuate did evacuate. Minus the 300 of course.
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