Going up: Japan builder eyes space elevator

Feb 22, 2012
Moon

A Japanese construction firm claimed Wednesday it could execute an out-of-this-world plan to put tourists in space within 40 years by building an elevator that stretches a quarter of the way to the moon.

Obayashi Corp claims it could use carbon nanotube technology, which is more than 20 times stronger than steel, to build a lift shaft 96,000 kilometres (roughly 60,000 miles) above the Earth.

The company said it would carry up to 30 passengers at a time and travel at a speed of 200 kilometres per hour for a week, stopping off at a station at 36,000 kilometres.

Tourists would stay there, but researchers and specialists would be able to travel all the way to the end, said Satomi Katsuyama, the project's leader.

"Humans have long adored high towers," she said. "Rather than building it from the earth, we will construct it from the space."

However, while Obayashi says the plan could work, there are presently no estimates for the cost of the structure, nor any idea where to build it, or who would pay for it.

Obayashi is just days away from completing work on Japan's tallest structure, the Tokyo Sky Tree, which will stand 634 metres (2,080 feet).

The tower will serve as a digital broadcasting antenna as well as a sightseeing attraction that allows uninterrupted views of the Japanese capital and beyond.

"We were inspired by construction of Sky Tree," which will open for business in May, she said. "Our experts on construction, climate, , design, they say it's possible."

When Obayashi is not drawing up plans to conquer space it works on a number of projects from building corporate headquarters, bridges and power plants to renovating ancient temples.

Among its portfolio are the Dubai Metro in , Universal Studios Osaka, Japan, and Stadium Australia, which was used for the Sydney Olympics.

Explore further: Testing immune cells on the International Space Station

add to favorites email to friend print save as pdf

Related Stories

Canada plans its first spaceport

Aug 19, 2006

Canada is reportedly planning to build its first spaceport, which will launch supplies to the International Space Station and even send tourists into space.

Virgin Galactic readies maiden suborbital flight

Dec 06, 2009

British billionaire Sir Richard Branson will unveil a craft on Monday that could soon carry tourists on an out-of-this-world trip into space -- for a mere 200,000 dollars. (Update: Virgin Galactic unveils commercial spaceship) ...

Japan's Mitsui in quake-zone solar plan: report

Jul 06, 2011

Japanese trading house Mitsui plans to build large-scale solar power plants with the capacity to supply 30,000 households in the tsunami-hit northeast, a newspaper reported Wednesday.

Recommended for you

Testing immune cells on the International Space Station

2 hours ago

The human body is fine-tuned to Earth's gravity. A team headed by Professor Oliver Ullrich from the University of Zurich's Institute of Anatomy is now conducting an experiment on the International Space Station ...

Easter morning delivery for space station

7 hours ago

Space station astronauts got a special Easter treat: a cargo ship full of supplies. The shipment arrived Sunday morning via the SpaceX company's Dragon cargo capsule.

NASA's space station Robonaut finally getting legs

Apr 19, 2014

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Sun emits a mid-level solar flare

Apr 18, 2014

The sun emitted a mid-level solar flare, peaking at 9:03 a.m. EDT on April 18, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful ...

User comments : 57

Adjust slider to filter visible comments by rank

Display comments: newest first

StarGazer2011
2.4 / 5 (18) Feb 22, 2012
space elevator is cool, but our civilisation doesnt have the capacity to spend 40 years building anything anymore. Its amazing the LHC got built. still, love the concept.
dogbert
2.3 / 5 (14) Feb 22, 2012
A space elevator is a good goal, but we currently lack the technology to build such a structure.

I am sure that Obayashi Corp considers this claim good P.R.
Bob_Kob
3.4 / 5 (10) Feb 22, 2012
Its funny how going 200 km/h is still an incredibly slow way of getting into space.
Egleton
1.6 / 5 (14) Feb 22, 2012
The 35 year doubling time of the population mandates that we move into new territory. Unacceptably high mortality will be the consequence of temerity.
Dr Gerard K O'Neill and co have shown us the business model.
Our automation technology will precede us.
There will be casualties.
This is not a choice that we are free to make.
Failure will lead to cannibalism.
antialias_physorg
4 / 5 (9) Feb 22, 2012
Its funny how going 200 km/h is still an incredibly slow way of getting into space.

Depends on how you define 'space'. To get to low Earth orbit (LEO) - e.g. the height of the International Space Station - would require a bit less than 2 hours. This still boggles the mind when you try to wrap your head around the fact that you'r going UP all the time.

36000km is geostationary orbit (GEO) (and I'd think that not many pople would like to be stuck on an elevator for a week)

The 35 year doubling time of the population mandates that we move into new territory.

Moving off world is not a solution to overpopulation (far too expensive as well as nowhere to go). But the 'population explosion' already shows first signs of leveling off. Remains to be seen whether we reach equilibrium before or after the numbers become unsustainable.
Resonance
4.5 / 5 (8) Feb 22, 2012
1. Build Space Elevator
2. Build Space Station which will be a harbor (for constructing large spaceships)/ solar power station.
3. Moon Base for development of *enormous* 'cheap' telescopes(which can be made on the moon) and neutrino/gravitational observatories
4. Explore the solar system with manned flights.
5. Leave the solar system.

The space elevator is very important. Rockets are too dangerous and expensive, and the turnaround time for a launch is ages. Maybe steps 1 and 2 are acheivable in 50 years.
antialias_physorg
3.8 / 5 (12) Feb 22, 2012
. Build Space Elevator
2. Build Space Station which will be a harbor (for constructing large spaceships)/ solar power station.
3. Moon Base for development of *enormous* 'cheap' telescopes(which can be made on the moon) and neutrino/gravitational observatories
4. Explore the solar system with manned flights.
5. Leave the solar system.

0. Have TONS of money and resources to spare.
hyongx
4.3 / 5 (6) Feb 22, 2012
Our automation technology will precede us.
There will be casualties.
This is not a choice that we are free to make.
Failure will lead to cannibalism.


Hahaha. This is HILARIOUS.
Lurker2358
2.5 / 5 (8) Feb 22, 2012
The 35 year doubling time of the population mandates that we move into new territory. Unacceptably high mortality will be the consequence of temerity.
Dr Gerard K O'Neill and co have shown us the business model.
Our automation technology will precede us.
There will be casualties.
This is not a choice that we are free to make.
Failure will lead to cannibalism.


The doubling rate is almost exactly 53 years, at present decade population growth rate, not 35 years.

Did you transpose the digits?
eigenbasis
4.8 / 5 (5) Feb 22, 2012
Things they must consider, degradation due to:

1. Ions in the upper atmosphere
2. Strength variations due to pressure/temperature/current gradients
3. Lightning and charge buildup/currents
4. Cosmic rays
5. Harmful aerosols in the atmosphere
6. Dust/Volcanic ash/particulate buildup over time

Also don't forget Coriolis force to conserve angular momentum and relativistic corrections
TheGhostofOtto1923
2.2 / 5 (10) Feb 22, 2012
space elevator is cool, but our civilisation doesnt have the capacity to spend 40 years building anything anymore. Its amazing the LHC got built. still, love the concept.
You forget the interstate highway system, the biggest thing ever built.
A space elevator is a good goal, but we currently lack the technology to build such a structure.
-says dog.

"Obayashi Corp claims it could use carbon nanotube technology, which is more than 20 times stronger than steel, to build a lift shaft 96,000 kilometres (roughly 60,000 miles) above the Earth."

-says a large corporation full of scientists and engineers who have actually studied the concept and have gone on record saying it is possible. Whose opinion might be worth more?
antialias_physorg
2 / 5 (2) Feb 22, 2012
At least dust/particle buildups is probably not going to be a problem (since elevators will be riding this thing up or down...so either that will clean it off or occasionally including a cleaning run shouldn't be too hard)

First thunderstorm will bring this thing down, though.
TheGhostofOtto1923
1.7 / 5 (12) Feb 22, 2012
First thunderstorm will bring this thing down, though.
-says AA

"Obayashi Corp claims it could use carbon nanotube technology, which is more than 20 times stronger than steel, to build a lift shaft 96,000 kilometres (roughly 60,000 miles) above the Earth."

-says a large corporation full of scientists and engineers who have actually studied the concept and have gone on record saying it is possible. Whose opinion might be worth more?
TrinityComplex
5 / 5 (4) Feb 22, 2012
This is really jumping the gun. As desperately as I want to see a space elevator/skyhook/Tethsat or whatever you want to call it there's no point in expecting anything to be started until they do a proof of concept with a thin tether attached to a small satellite. I haven't even heard of any agency gearing up to do such a test, just a bunch of over-ambitious 'plans' to build a hotel/casino in geostationary orbit.

When they do get it built I would be very interested in how much power it could produce. Anybody remember the test in the 90s where the shuttle released a tether into the atmosphere and it collected massive amounts of electricity before an arc cut it off? I'm curious if a tethered satellite could harvest energy that way. Before you say 'it's stationary, whereas the shuttle tether was moving', the atmosphere would be moving around it, causing a similar effect.
TheGhostofOtto1923
1.6 / 5 (12) Feb 22, 2012
The 35 year doubling time of the population mandates that we move into new territory. Unacceptably high mortality will be the consequence of temerity.
-The myth that humanity will actually LEAVE earth in any great proportion. Like any lifeform it is capable of quickly growing to fill any new niche it inhabits. Overpopulation will continue to be a problem on earth until the conditions which create it are addressed. Namely, religion.
Telekinetic
3 / 5 (10) Feb 22, 2012
Wouldn't it benefit a corporation to give the impression of being at the forefront of technology when 14 billion dollars worth of Fukushima clean-up contracts are up for bid?
antialias_physorg
3 / 5 (4) Feb 22, 2012
Well, they have to make it pretty thin or its own weight will bring it down. And I'm pretty sure a lightning strike does char stuff at the point of contact pretty badly (30000 degrees celsius seems an awful loot) which might impair stability somewhat. I've worked with a group that did lasercutting of carbon fibre, and that used temperatures and energies far below what a bolt of lightning can come up with (which is up to 5 billion joules).

If they can handle this - great. Or, if they have found a place on Earth that doesn't suffer from thunderstorms (and I honestly don't know if such a place exists. Deserts would probably be a good place). But I can't find an indication that they have adressed this

Remember what happened with the space tether experiment in 1996? That was a fairly solid tether and it melted through by induced 3500Volt from the Earth's magnetic field.

I certainly would like to see them try. It would be awesome if it worked.
TrinityComplex
5 / 5 (1) Feb 22, 2012
@antialias
I know that they had some ideas for how to prevent what happened to the thether, such as exposing a material with a higher conductivity at regular intervals along the tether and having the spike in current run to a safe ground (or some unit that could absorb or dissipate such current), which is potentially the means of energy production I mentioned.
antialias_physorg
1 / 5 (1) Feb 22, 2012
Was that tested? Might work. After all: you probably only have to harden the lower 150km or so - the extra weight issue might not be as bad as I thought.
And the tower doesn't move relative to the Earth's magnetic field so there is little danger from that angle (except for when the field gets deformed by solar storms - but I have no clue how much current that would induce.)
Sonhouse
2.3 / 5 (3) Feb 22, 2012
The 35 year doubling time of the population mandates that we move into new territory. Unacceptably high mortality will be the consequence of temerity.
-The myth that humanity will actually LEAVE earth in any great proportion. Like any lifeform it is capable of quickly growing to fill any new niche it inhabits. Overpopulation will continue to be a problem on earth until the conditions which create it are addressed. Namely, religion.


Amen to that:) I keep watching for an anti religion virus but in vain.

Before they make grand pronouncements about space elevators, which for sure would be wonderful, they need to prove they can make thousands of miles of this super strong cable, which btw, could be 100 times stronger than steel, but now we make the stuff in one or two centimeter lengths so they better do their homework first. Lets see them make even ten meters of the stuff before strutting your feathers.

2000 foot building in a 9 Richter scale zone??
TheGhostofOtto1923
1 / 5 (5) Feb 22, 2012
Much work done already on concept and design:

"Edwards' work was expanded to cover the deployment scenario, climber design, power delivery system, orbital debris avoidance, anchor system, surviving atomic oxygen, avoiding lightning and hurricanes by locating the anchor in the western equatorial Pacific, construction costs, construction schedule, and environmental hazards."
http://en.wikiped...elevator
nkalanaga
2.3 / 5 (3) Feb 22, 2012
Coriolis forces won't be a problem. The elevator has to be on the equator, to keep the tower vertical, so all stresses will be radial.

Earth's uneven gravitational field will be an issue. Geostationary satellites tend to migrate to certain points along the equator, and the tower will try to do the same. It will almost have to be anchored under one of those points, most of which are over the oceans.
TopherTO
4 / 5 (4) Feb 22, 2012
During the week long trip you could squeeze in a few renditions of Stairway to Heaven.
MRBlizzard
1 / 5 (2) Feb 22, 2012
I've looked at the calculations. The amount of material that has to be lifted up for a single strand is measured in cubic kilometers. We won't do that with rockets.

The thickest point on the Space Elevator is at Geosynchronous height. The bottom strand and the top most centrpidal force mass must be held together at geosynchronous height.
animah
not rated yet Feb 23, 2012
AFAIK the only industrial product in existence that fits the article's "carbon nanotube technology" quip is carbon nanotube reinforced polymer (CNRP), a descendent of carbon fibre cloth.

It is starting to show up in state of the art military tech like the X-35 so we should start seeing civilian applications in the next few years.

That said while carbon fibre has gone from $150 to $10 a pound in ten years, that's still not cheap. And CNRP is not just orders of magnitude more expensive to make, large manufacturing machinery for it has not even been developed yet.

All in all I think it'll take a couple of decades at least before making a tether that long becomes possible, but it's definitely not science fiction.
Peter_McArthur
5 / 5 (1) Feb 23, 2012
Actually, you could in theory build a space elevator out of steel, however the required taper ratio of the cable would be prohibitively expensive. I've looked at the proposed design extensively and my opinion is that single-stage-to-tether would be simpler to build and more economical. Especially if SpaceX could provide the first stage...
roboferret
not rated yet Feb 23, 2012
I think passing a conductive strand through the ionosphere is going to present it's own challenges. Then there's the lethal dose radiation passing through the Van Allen belts to contend with. These are engineering challenges, and will be overcome with the right incentive. We just need a business case, get prospecting those asteroids!
GlucNifer
5 / 5 (3) Feb 23, 2012
Just use carbon fiber Legos ..done
(plus child labor is cheap)
Shelgeyr
1.6 / 5 (7) Feb 24, 2012
@antialias_physorg is on the right track with worries about lightning and conductivity. However, I think the main problem hasn't yet been addressed.

And before I belabor the issue, let me point out that I'd absolutely love for there to be a space elevator. I'm not against the concept at all.

But it is never going to happen.

Sure, they can probably build cables light and strong enough, but that's not the issue, and frankly neither are thunderstorms (although that's a lot closer to the mark). Anything will conduct electricity if the voltage is high enough, and a space elevator would have to cross multiple energized plasma "double layers".

Think of it as laying a conductor across the poles of a planet-sized capacitor... BZAP! Megalighting! Or, far more likely, just a fizz-pop cable severing long before touchdown.

Sad, really... I'd love a space elevator!
baudrunner
1 / 5 (5) Feb 25, 2012
It was always a stupid idea and it still is. A project like that will cost trillions of dollars. And you know what? They will probably begin by building a cheaper steel tower with an elevator to take you to the carbon nanotube elevator. You see, that's just how stupid this stupid idea really is.
Skepticus
2.4 / 5 (8) Feb 25, 2012
New flash:
"A shipment of Koran was accidentally burned by induced power surges in one of the cable car..."

You know what will happen next...
Jotaf
5 / 5 (1) Feb 25, 2012
As much as I would love this, Shelgeyr is right -- you're essentially short-circuiting the layers of the Earth's atmosphere, which have different charges. I don't think it would last much.

Building a large tower to extract energy from this charge difference, however...
braindead
not rated yet Feb 25, 2012


"Or, if they have found a place on Earth that doesn't suffer from thunderstorms ...."

Could the space elevator rise at an angle from the planet surface? if not it has to rise from the Equator if it is to cross through geostationary orbit. That puts it in a belt of intense lightning activity for the first few kilometres above the ground. Perhaps in reality it would have be tethered at several point on the ground joining at a node somewhere above ( an excellent tourist platform this would be)
This would be more stable and could build in redundancy in case of a cable failure though the falling cable would be an enormous danger. Perhaps cable anchors could be in the ocean bed? Security against terrorist attacks would be difficult to effect. Radiation exposure on the ride up could be an issue.
antialias_physorg
4 / 5 (3) Feb 25, 2012
if not it has to rise from the Equator

How about putting it at the poles?
mosahlah
1 / 5 (3) Feb 26, 2012
I guess we've already solved the issue of cleaning up all the space junk threatening to fling this contraption into the cosmic abyss. Otherwise, we have a way to harden this thing to resist a couple of tons of magnesium traveling 15,000 miles per hour? Feel free to sharpshoot my layman's numbers, and then pony up with the real costs of solving those issues.
Sinister1811
1.4 / 5 (11) Feb 26, 2012
Having worked in a few hotels, I can't even begin to imagine the difficulty of maintaining a long-term space elevator.
mosahlah
2.4 / 5 (5) Feb 26, 2012
if not it has to rise from the Equator

How about putting it at the poles?


Holy shite, that's actually a really good idea. I'm not sure about the math, but if you spin this thing faster than the earth, it solves the problem of building it in space, and makes the overall length a hell of a lot shorter. All you gotta do is start with a big enough centrifugal device, airfoils, circular train track, whatever. Just spin it till it lifts off and reel it out. Use electrical locomotive energy and scale it up until the wind resistance is overcome by mass. Correct me if im wrong, but i suspect the mechanical velocity near the pole shouldnt be insurmountable. No billion dollar launch vehicles necessary. Make it short and fast enough and you might get it under a lot of the junk and low earth orbital traffic. Damn, this thing looks doable.
Jeddy_Mctedder
1.3 / 5 (6) Feb 26, 2012
how do science fantasy articles like this get on physorg?
i guess i shouldn't be surprised since there are cold fusion articles still on physorg
wtf?
mosahlah
2.6 / 5 (5) Feb 26, 2012
how do science fantasy articles like this get on physorg?
i guess i shouldn't be surprised since there are cold fusion articles still on physorg
wtf?


Fantasy? Impossibility has a death grip on your scrotum? Anyone challenge me, I think I have a mechanical solution within possibility. Just don't challenge my math skills. I'll let you guys with degrees handle the real work.
RealScience
not rated yet Feb 26, 2012
Putting it at the poles on a track is an interesting idea.

The cable would be nearly horizontal and hence would remain in the lower (thick) atmosphere for a long time. A quick estimate is 180 km until the atmosphere is half as thick and 250 km to where the air is 1/4 as thick.
But then it wouldn't be moving that fast - at 10x earth revs that is only ~450 km/h at 1/2 density and 630 km (a bit slower than a commercial jet) where the air is 1/4 as thick (about as thick as a commercial jet flies through). So you could have rotary power on the ground and an airplane every few tens of km to keep the cable from sagging to the ground.

Fly a payload up with a plane and sky-hook it to the cable. Payloads would be going almost horizontal at first, with gravity's vector along the cable just more than balanced balanced by centrifugal force, so the airplanes flying a bit faster would sling the payload up the cable.

Unfortunately there are a few problems.

-continued-
RealScience
not rated yet Feb 26, 2012
Pulling a cable tight enough top keep it from sagging takes much more force than the weight of the cable, so the cable would have to be much stronger to keep from sagging in the middle under its own weight. In the 10 Revs/day example above the planes could only support the cable to a ~3 degree slant, so the cable would have to be able to support ~20x its own weight. And at 10 RPD the cable would only be ~3x shorter than an equatorial cable.

So while it truly is an interesting idea, it looks to me like it wouldn't actually work as well mechanically as an equatorial cable would.
And while it would avoid the most cluttered orbits and also lightning strikes, the north pole is water and flying a dozen jets around the south pole creates logistical problems.

(But the idea merits a 5 anyway.)
packrat
1 / 5 (3) Feb 26, 2012
slight off subject but if you could keep the built up static charge at bay somehow and not fry your equipment, it should make a REALLY GOOD long wire type amateur radio antenna!
mosahlah
1 / 5 (3) Feb 26, 2012
Challenge accepted. Use aerodynamic surfaces along the first section of "cable" to lift the cable towards the earths axis, that way it lifts the average of the longitudal plane above the thickest portion of the atmosphere. Gravity will cause it to sag all along it's length, back towards the equator, but the first 1/4 or so should take off at somewhere around a 30-45 degree angle. It takes a lot more energy to operate than the cable from the equator going out past geosynchronous orbit, but it should be a lot less total mass, easier to deploy, and a lot more realistic. Build the thing in 3 stages, a fast spinning "helicopter mast" stage that gets the thing off the ground, an initial space stage that creates the centrifugal power to deploy the main structure, and a load bearing stage with enough ballast to lift a vehicle, and ports to launch orbiters, or.... retrieve orbiters? Again, this whole thing might make it under low earth orbit if my powers of intuition serve me properly
mosahlah
1 / 5 (3) Feb 26, 2012
Another point. You guys think there's electrical energy up there that can be harvested and/or power this thing? Also, you should be able to land this thing without totally destroying it if the aero surfaces extend the length.

And south pole. Totally. Very little weather there. Solid ground. No air traffic.
mosahlah
1 / 5 (3) Feb 26, 2012
Btw, I'm just a green beret in Afghanistan. Not a scientist or anything like that. If someone out there builds this thing, can you give a job in charge of security, or a door greeter or something? I'm coming up on retirement and the war's winding down. Looking for options.
antialias_physorg
not rated yet Feb 27, 2012
How about putting it at the poles?


Holy shite, that's actually a really good idea.

I think I have to shoot down my own idea here. The space-side anchor needs to be in orbit around the earth - it can't hover above the poles (with no angular speed it would simply drop).
So I'd have to rescind that and say the equatorial position is probably the only stable one.

The only other stable places for an anchor would be Lagrange points of the Earth-Moon system. but these are too far away (and also in relative motion to the Earth's surface)
antialias_physorg
not rated yet Feb 27, 2012
You guys think there's electrical energy up there that can be harvested and/or power this thing?

This has been tried with a tether on two space shuttle missions (STS-456 and STS-75)
http://de.wikiped...e_Tether

You can use the electricity but at the expense of dragging you into a lower orbit (something you'd probably not want for a space elevator). But a space elevator (the cable part) does not require power. The cabin does. And it can be self powered.

There's the USST Space Elevator Games which post a challenge for such contraptions every year (or at least have until 2009).
http://www.spacee...d-tests/
Though the current aim is 5m/s (18km/h) - far from the envisioned 200km/h
mosahlah
1 / 5 (3) Feb 27, 2012
No, it doesn't need to "orbital". It merely needs centrifugal force. The tether performs the function of gravity but instead of drawing the mass towards the earth, the tether pulls in the direction of the axis. Add an aerodynamic lifting surface to the structure and you can elevate the average plane (I say average, because gravity will cause the tips to droop back towards the earth, giving the structure an arch) a few km..Also, my concept is a spinning structure, like a helicopter blade, and requires energy be added to stay aloft, unlike the stationary equatorial elevator, but all you need is a spinning mast to launch it, circular rail based tractor to power it, and you might be able to "land" it when you are finished. It wouldnt be weightless at any point on its structure, the vehicle would truly be "launched" from its port somewhere near the ballast.
mosahlah
1 / 5 (3) Feb 27, 2012
I can't believe nobody else sees this. The aerodynamics carry much of the weight of the lower section, centrifugal force carries much of the weight of the mid-section, and the upper portion is only supporting ballast and maybe 10 kilometers of material. Like I said, I'm no physics major, but i believe total length is not very important. Maybe a 100km will do. How difficult can that be? You can probably build it tomorrow out of kevlar and graphite.
antialias_physorg
not rated yet Feb 27, 2012
Doesn't work. Aerodynamics (like helicopters) only go to 10 km or so. The amount of weight you could alleviate with such 'active lifting' would be negligible.
We're dealing with 36000km of cable, here.
mosahlah
1 / 5 (3) Feb 27, 2012
Doesnt work?? The wings on a 747 are what, a 100ft long?, and they lifts 100 tons each. The "wing" portion only has to lift itself and change the angle of the lower portion to get the mid portion out of the thick layer of atmosphere. Why 36,000km??? Again, I dont think the overall length is very important. The rate of spin and enough mass at the apex to overcome the drag in the atmospheric portion is the only thing that matters. You can achieve an orbit, albeit shortlived, with 100km of altitude, so why not start there and add enough velocity and ballast to overcome gravity?
RealScience
not rated yet Feb 28, 2012
@antialias - going straigh up from the pole wouldn't work, but going almost flat out from a tower at the pole would get rotation, and as mosahlah point out, the rotation could be much faster than once per day.

@mosahlah - I overlooked a factor in my calculation of the force on the cable - it is only the weight of the to that point that has to be multiplied, not the whole cable. So the 10 Rev/day cable example would have tension roughly equal to 25 times the 270 km, not 25 time the whole cable.
25x270 is almost exactly the 6400 geopotential kilometers of cable needed in the equatorial case. In the equatorial case the cable tapers to very thin at the surface, while in the polar case it doesn't. But in the polar case the cable is shorter (~1/3 the length at 10 RPD). With steel the equatorial case would win. With perfect carbon nanotube cable the polar case wins even at 10 RPD.

So great idea!
RealScience
not rated yet Feb 28, 2012
@Antialias - no, by going faster than 1 RPD, mosahlah doesn't need 36,000 km of cable. At 10 Rev/day he'd only need about 11,000 k of cable.

@mosahlah - the tension would pull the cable essentially flat at the start, and gravity would pull it down even further. Aerodynamic lift would to overcome gravity would be reasonable, but to overcome tension would be many times higher.

Going higher than 10 RPD would shorten the cable, but the velocity in the atmosphere would get high enough to cause problems - one would need a supersonic craft before 20 RPD. Basically have it so at the height that a big jet can fly to the cable is moving at the speed that a big jet flies. That would be something like 12 RPD, which still needs 10,000 km of cable.
RealScience
not rated yet Feb 28, 2012
But lets say that we can have a supersonic cable - carbon nanotubes are fairly heat resistant. The Concorde flew at Mach 2, and only needed to be at 60,000 feet to avoid overheating that speed.
The south pole is already at 9,000 feet, and the polar low typically keeps the air pressure at 13,000 feet, so one would only need a 47,000 foot tower to run comfortably at Mach 2.

The air pressure won't drop in half until 180 km out, that allows Mach 2.5 for the same temperature. Mach 2.5 is 850 m/sec, so that's 850 / and Mach 3 at half pressure is the at 180 km and 180 km is 1.1 million meters around so that's ~1300 seconds or ~22 minutes to go around.
LEO requires 7800 m/sec so that's 9x the speed and requires 9x180 km = 1620 km of cable.
Escape velocity (really interesting) requires about 2300 km of cable.

I don't think that it is easy, but I don't think that it is impossible, either.
And Mach 2 only requires around 60 km of cable!
Shelgeyr
1.2 / 5 (6) Mar 06, 2012
@antialias_physorg said:
I think I have to shoot down my own idea here. The space-side anchor needs to be in orbit around the earth - it can't hover above the poles


Glad you realized that! I need to split hairs (apologies in advance) and point out that it isn't the space-side anchor that will be in actual orbit. Rather it will be roughly the center of gravity of the entire structure, or a "mid-way" point where you'd feel zero-G in the elevator, which means that the space-side anchor will be well beyond the orbital point, and anyone on the anchor would feel a strong ersatz "G force" pulling away from the planet.

That's kind of the point, by the way, at least in terms of using it as a launch facility - from the anchor all you need to do to be flung into space is to simply let go... no rocket firing necessary (except for course corrections post-launch).
RealScience
not rated yet Mar 06, 2012
@Shelgeyr - yes, actually the construction phase could just reel out more cable until it all balances (this takes less mass than a traditional counterweight since the mass averages farther out). Then just let your craft slide out the cable until your velocity is just right, and then let go. If I remember the calculation, the 'tail' is several times longer than the earth-to-geostationary distance, but one can gain several tens of km/sec for 'free' (borrowing from the earth), which is enough to coast to mars.
Shelgeyr
1 / 5 (6) Mar 14, 2012
I had an idea regarding the space elevator that I think A) might work, and B) would still likely be a very bad idea. It is this:

Since I believe the downside to having a space elevator cable cross different layers of atmospheric charge (or different plasma "double layers") would be (at least) the cable's vaporization..., would it be possible to divert any discharge through a series of what would effectively be bristling lightning rods feeding into a plasma-containing tube running along the outside of the elevator cable?

This wouldn't be "insulation", per se, but rather a highly conductive path to discharge the local environment through which the cable passes?

The reason I think this would be a BAD IDEA, if it worked, is along the lines of "but don't we NEED those areas of separated atmospheric charge?" In other words, wouldn't the solution end up being worse for the planet than not having a space elevator?

Again, I'd love to be wrong. Please knock holes in this if you can.

More news stories

Easter morning delivery for space station

Space station astronauts got a special Easter treat: a cargo ship full of supplies. The shipment arrived Sunday morning via the SpaceX company's Dragon cargo capsule.

Growing app industry has developers racing to keep up

Smartphone application developers say they are challenged by the glut of apps as well as the need to update their software to keep up with evolving phone technology, making creative pricing strategies essential to finding ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.