# Japan Starts Space Elevator Experiments



## Vince W (Sep 7, 2018)

Arthur C. Clarke's idea of a space elevator is coming closer to reality.

Japan starts space elevator experiments


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## Vertigo (Sep 7, 2018)

That's actually quite exciting, though I doubt it will appear in my lifetime. I wonder how practical it would be to have some sort of intermediate stations along the way to geosynchronous orbit. If they could it would make it even more economically viable for launching low orbit satellites as well.


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## Venusian Broon (Sep 7, 2018)

It's a great dream, but I believe unfortunately we are still really far from getting something even close to ACC's original 

The main issue is, I believe, (and slapping carbon nanotubes as a catch word into it doesn't solve it) is having a cable strong enough. We are still in the realm of science fiction rather than science at the moment. 

But I am optimistic, as advances in material science in the coming decades will probably make our current knowledge look as if we were just medieval smithies. So perhaps there will be a breakthrough on some sort of cheap and amazingly strong cable 'stuff'!


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## Vertigo (Sep 7, 2018)

Venusian Broon said:


> It's a great dream, but I believe unfortunately we are still really far from getting something even close to ACC's original
> 
> The main issue is, I believe, (and slapping carbon nanotubes as a catch word into it doesn't solve it) is having a cable strong enough. We are still in the realm of science fiction rather than science at the moment.
> 
> But I am optimistic, as advances in material science in the coming decades will probably make our current knowledge look as if we were just medieval smithies. So perhaps there will be a breakthrough on some sort of cheap and amazingly strong cable 'stuff'!


Yeah, that's why I doubt it will be in my already slightly aged lifetime!


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## Venusian Broon (Sep 7, 2018)

Vertigo said:


> Yeah, that's why I doubt it will be in my already slightly aged lifetime!



Good though to do tests with basics bit's n' pieces to test out concepts etc...


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## -K2- (Sep 7, 2018)

Hopefully, by the time they figure this all out (before disregarding it as unviable), advanced propulsion drives will be developed making it obsolete before it is even built.  And I don't mean some Vernian moon gun either.







K2


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## Vince W (Sep 7, 2018)

If the material required will be super strong, why not use them to build very _very_ high rises. Use them almost like a stalk and then build living 'leafs' off them. I may need to think about this.


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## Vertigo (Sep 8, 2018)

Vince W said:


> If the material required will be super strong, why not use them to build very _very_ high rises. Use them almost like a stalk and then build living 'leafs' off them. I may need to think about this.


I think the material for a space elevator needs to be strong under tension not compression. I'm not brilliant at that sort of engineering though so I may be wrong.


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## JoanDrake (Sep 14, 2018)

I had been under the impression that some of the "buckyball" carbon fibers approached the strength needed now. 
And building whole cities along them is an intriguing  idea


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## Robert Zwilling (Sep 15, 2018)

In an elevator built on the Moon, could it travel at fast speeds and you would only feel normal pressure because of the low gravity pull to start with.


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## Vertigo (Sep 15, 2018)

You would feel exactly Moon gravity plus whatever acceleration you are subjected to.


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## Daysman (Dec 4, 2018)

Okay, so I can see this thread died long before I arrived here, but I thought it worth adding that a lunar elevator doesn't need exotic materials.


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## chrispenycate (Dec 7, 2018)

Daysman said:


> Okay, so I can see this thread died long before I arrived here, but I thought it worth adding that a lunar elevator doesn't need exotic materials.


Depending on your definition of 'exotic' for fizzycists it tends to involve at present undiscovered subatomic particles. But it's true that the assumption that 'nothing could carry its own weight over that length' is somewhat like the argument that 'a chemical rocket would never be able to lift anything to orbit - the fuel would weigh too much to accelerate itself' (overcome by multistage rockets, and since by material science, but it looked like a game stopper at the time) - we could actually build one out of steel, and ajust the taper so the structurally more rugged bit in the lower gravity higher section was only carrying the weight of the thinner bit. It would be a ridiculous size (partly because there I've ignored atmospheric effects and the mass of the ascending capsule, but that's engineering) but the real bummer is the counterweight, either in geostationary or just slightly outside, several hundred thousand tonnes we'd either have to capture from asteroidal mass or lift up from Earth, and the fact that each rising load would minutely slow the rotation (conservation of momentum) so every load going into orbit  would have to carry some fuel (or at least reaction mass) to keep the system stable. You wouldn't want that crashing down to Earth - it'd make the dinosaur killer look like a firecracker. It would also make a marvellous target for terrorists - most of my 'beanstalk' stories have the base of the tower in Equador, near Quito - get as much height as you can through mountain, and the thinner the atmosphere the less wind drag. Arthur C. moved Sri Lanka onto the equator (very important, that - I wonder which bit of the equator the Japanese are planning to buy) and added some mountain height - Whichever country is chosen on the equator (and there aren't that many options) is going to make enormous amounts of money, but will need to be politically very stable…
'Course, if you're sending in from orbit (down from orbit after the first kilometre or two) washing machines manufactured from asteroid steel, and the same massis coming to Earth as is being lifted away, this will balance, so interplanetary trade can't run on too many surpluses…


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## Venusian Broon (Dec 7, 2018)

chrispenycate said:


> Depending on your definition of 'exotic' for fizzycists it tends to involve at present undiscovered subatomic particles. But it's true that the assumption that 'nothing could carry its own weight over that length' is somewhat like the argument that 'a chemical rocket would never be able to lift anything to orbit - the fuel would weigh too much to accelerate itself' (overcome by multistage rockets, and since by material science, but it looked like a game stopper at the time) - we could actually build one out of steel, and ajust the taper so the structurally more rugged bit in the lower gravity higher section was only carrying the weight of the thinner bit. It would be a ridiculous size (partly because there I've ignored atmospheric effects and the mass of the ascending capsule, but that's engineering) but the real bummer is the counterweight, either in geostationary or just slightly outside, several hundred thousand tonnes we'd either have to capture from asteroidal mass or lift up from Earth, and the fact that each rising load would minutely slow the rotation (conservation of momentum) so every load going into orbit  would have to carry some fuel (or at least reaction mass) to keep the system stable. You wouldn't want that crashing down to Earth - it'd make the dinosaur killer look like a firecracker. It would also make a marvellous target for terrorists - most of my 'beanstalk' stories have the base of the tower in Equador, near Quito - get as much height as you can through mountain, and the thinner the atmosphere the less wind drag. Arthur C. moved Sri Lanka onto the equator (very important, that - I wonder which bit of the equator the Japanese are planning to buy) and added some mountain height - Whichever country is chosen on the equator (and there aren't that many options) is going to make enormous amounts of money, but will need to be politically very stable…
> 'Course, if you're sending in from orbit (down from orbit after the first kilometre or two) washing machines manufactured from asteroid steel, and the same massis coming to Earth as is being lifted away, this will balance, so interplanetary trade can't run on too many surpluses…





Spoiler: Kim Stanley Robinson Mars series



From memory Kim Stanely Robinson's Red (or possibly Green) Mars had a terrorist attack on the Martian elevator that caused it to fall back to ground, beanstalk style.


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## chrispenycate (Dec 7, 2018)

Has to be green or blue - they couldn't have built the thing in Red. Mt Olympus sticking right out of the atmosphere is an advantage, as is the lower gravity, but Phobos coming round every so often through the cable is a bit of a problem (though A. C. C. did indeed solve it, it's reliant on humans getting things right - I'd have preferred it automatic). Yes, the cable/tower wrapping four times round the equator and bouncing buckyballs everywhere, and I don't want to calculate how many gigawatt/years of energy being fed into the geology - a nice image.


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## Daysman (Dec 7, 2018)

Mmm...

The potential for disaster suggests building _experimental_ tethers above the moon may be our only reasonable way forwards... _and a goldmine for SF!_

@chrispenycate, might I hurl a wiki article your way?

Lunar space elevator - Wikipedia

It mentions using _high-strength para-aramid fibres_ and addresses the need for taper, or the lack there of...

Do you think it has any weight?


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## Scookey (Dec 30, 2018)

An idea I heard mooted a few years ago was to build a tower to the outer atmosphere using inflatables and launch rockets from a platform there. The idea being the fuel needed to get to outer space from that height was much less than from ground level. Don't recall how they intended to get to the platform though. Maybe by balloon?


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## Parson (Dec 31, 2018)

Scookey said:


> An idea I heard mooted a few years ago was to build a tower to the outer atmosphere using inflatables and launch rockets from a platform there. The idea being the fuel needed to get to outer space from that height was much less than from ground level. Don't recall how they intended to get to the platform though. Maybe by balloon?



Actually that sounds like a much more likely near term project than the jazzy space elevator and the very fear inducing tether it would require.


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