Space Elevator: High Hopes, Lofty Goals

Yahoo! News ^ | 9/17/03 | Leonard David

[Heyworth]

You and I may someday have the chance to visit space by train for the price of a trip to Europe today. What a great time to be alive!

You know, I'll bet that someone has written that very same sentence at least once every decade for the last 100 years.

My personal disaster scenario is that the whole thing will turn the earth into a giant lopsided bolo going whoop-whoop-whoop into the sun.

[JohnBovenmyer]

Chimborazo volcano

Is it active, dormant or really dead? Don't put all your eggs in a live basket.

[Bloody Sam Roberts]

Ping!

[Brett66]

Why can't the thing be "anchored" from a ship?

The elevator they're proposing will be, that's what makes it an even more attractive proposition than the usual mountain based ones. It will put it out in the middle of the ocean far away from a potential terrorist/airplane strike and it will be able to manuever the cable to avoid orbital debris. It looks like they've got all of the major conceptual problems worked out. I'm beginning to believe this thing is going to be built within the next thirty years or so.

Space elevator is anchored at ocean-based platform. Concept is getting a serious technical look by engineers and advanced planners.

[Bloody Sam Roberts]

What happens when this thing breaks and falls back down to earth?

Why would you think it would fall to Earth?

Isn't it just as like that the inertia built up from centrifugal force would cause it to go flying away from Earth?

I suppose it all depends on where the sucker breaks.

Either way, whomever is in it's path will undoubtedly have little time for more than a simple, "Oh $h!t".

[Reeses]

The Chimborazo volcano is extinct though there are active volcanoes in the area.

[Brett66]

Ping.

[Flightdeck]

If geosynchronous orbit is ~22,000 miles up, what's going on with the other 40,000 miles of ribbon that is supposed to be needed for the elevator?

[RightWhale]

the other 40,000 miles

The balance is deployed above geosynch altitude. For balance.

[Flightdeck]

When you say they can maneuver the elevator, you're implying that the anchor isn't firmly attached to the earth's crust. The force pulling up on the anchor would have to be massive enough to lift any "maneuverable" ship out of the water, although I don't know about the oil platforms

[Brett66]

The force pulling up on it will be roughly balanced with the weight of the cable, with allowances for payload on the cable. It won't be near enough to lift a ship of several thousand tons.

[Centurion2000]

bump

[edwin hubble]

Great work on this thread, RightWhale.

Re: the latitude of the anchor point. I got into a discussion with Boris back in July on this subject.
He insisted that only an equatorial anchor will work.
(I heard later that Clarke had 'moved' the anchor point Sri Lanka to the equator in his novel 'Fountains of Paradise'.

But here are some results of calculations by Blaise Gassend of MIT with graphs and analysis of several space elevator designs with non-equatorial anchor points.

http://www.mit.edu:8001/people/gassend/elevator/off-center-elevator.html

And, here is that space elevator thread from July 28th:
http://www.freerepublic.com/focus/f-news/952771/posts?page=107#107

[RightWhale]

The force pulling up on the anchor

That is correct. The entire structure would be in tension, so the heavier the structure and elevators [assuming multiple elevators so they can lift enough cargo to make it worthwhile] the greater the tug on the anchor. You'd eventually want something the weight of the Cheops pyramid at the ground end.

[RightWhale]

Tnx for checking in. The MIT link might be dead.

[edwin hubble]

Sorry, the site for the link in #58 (Space Elevator calculations and graphs) seems to have been pulled by the author at MIT.

But the link to the July FR thread on Space Elevators is good.

[Boiler Plate]

23000 miles up is geosynchronous orbit or in other words zero gravity rotating with a period of 24 hours. In order to get tension on the cable you have to further out and still rotate at a 24 hour period.

[norraad]

I still see a little pin in big tire.

Action metaphors on earth

or erf in ebonics

[Centurion2000]

We won't be able to build a space elevator cost-effectively until the cable can be manufactured in space.

We have to get a counterweight and raw materials (asteroid) towed back from the Asteroid Belt.

Then they can manufacture the cable at the source and drop it.

[Consort]

How big of a figure 8 will the platform trace in orbit and on the ground?