Coolest Thing I Have Heard About In Awhile

Mike Finley

Anybody heard of the space elevator? First proposed in 1895 by a Russian scientist and later popularized by Arthur C. Clarke in his sci-fi book The Fountains of Paradise, basically it is a 62,000 mile cable held tight by the force of the planet's rotation. The same theory as taking a long string with a ball on the end and spinning it over your head, the string stays staight and tight. Basically all you need is something to climb the string into space. Considering that the space shuttle's weight is only 5% cargo and 90% fuel you can see how a space elevator could reduce the cost of getting something into space by 98%. With the average satelite costing $500K launch you can imagine the possibilities.

There have been two stumbles to actually making it work, 1 being no substance has been strong and light weight enough to work as the string. That was until about 10 years ago when the Japanese invented carbon nanotubes, which are 100 times stronger than steel and weigh 1/5th as much. Tests have show a carbon nanotube sting the width of a thread to be able to hold a car off the ground. Currently a gram of carbon nanotube costs $500 to manufacture. But if you consider the history of Kevlar and much of an unbelievable and magical product it was and how expensive it was and how cheap it is now...

The second stumble has been a vehicle to climb the string like an elevator climbs it's cable. Last year NASA created "the elevator games" with a 200K prize for the first team to make a machine to climb a 200 ft tether powered by the light from a 10,000 watt light bulb. The winner got 40 feet. This year NASA doubled the prize and so far there are 45 teams entered. Nasa says this year it won't be a question of how far someone gets up the tether, but who gets up the fastest.

ProWallGuy

Very cool stuff.
Wasn't it you who posted aways back about the 'vortex', or 'tornado' machine, that would eat up any debris and output dust? Someone posted a video of the thing, and it looked pretty darn nifty.

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Bone Saw

neat stuff, space facinates me like a little kid, imagine the cable snapping and slingshoting the "elevator terminal" into oblivion if the centrifugal force of the earths rotation could keep the "string" tight how do we not get getting flung off this place??? very interesting, got any links mike?

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Mike Finley

Isn't that how we got Doctor Who?

Floorwizard

I thought I saw that on a show. And they said it was probably a fake.

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reveivl

The way I understand the concept is that you put a satellite into geosynchronous orbit and then start unreeling TWO lines, one in towards earth and the other out, away from earth. This not only stabilises the procedure but also gives you a launching platform at the far end, which is really whipping around.

The force on the string should actually be relatively small, the satellite is in a stable orbit so the string only (only!) has to be strong enough to hold itself and whatever load you put on it. It's not holding the satellite still.

If the string were to break at the top end then it would wrap itself around the earth several times!

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firemike

I remember talking about this in science class in high school (late 70's) Some of the problems we discussed back the were wind load, there's a lot of surface area on a cable going 25+ miles through the atmosphere. Since roughly 7 miles of it go through the troposphere where our weather occurs, then there is 20+ miles of it going through the stratosphere. (Look how much lateral strain there is on a hundred or so feet of kite string a on a windy day.) Then you have the solar wind to contend with, plus micro-meteors, lightning, airplanes, space junk, etc.

Then there was the traction aspect of it. The cable has to be big enough for a mechanism to be able to grab it enough to hoist the elevator without slipping, especially when the cable is wet/icey.

If I remember, I think we decided that we needed to invent an anti-gravity unit instead...

Gordo

Remember those jet propelled back packs from the 70's. Those things always fascinated me.........Six Million Dollar Man!

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Looks like some pros were here.