Print 131 comment(s) - last by UncleSnake.. on Sep 30 at 5:23 AM

A Japanese artist's rendition of the anchor platform that would rest at the bottom of the elevator.  (Source: The Times Online)
Will Japan be the winner of the space elevator race?

From wallet cell-phones to robotic maids, Japan has seemingly been one step ahead of the U.S. in hot technology for the last couple decades.  The hottest products in the U.S., like the iPhone, are passé in Japan.

Perhaps, it is not surprising that Japan is looking beat the U.S. to become the first to construct a space elevator.  While the U.S. still struggles, trying to devise a better rocket-launched space plane, Japan is considering becoming the first to bypass traditional launches, in the process saving time, money, and energy.  While Japan's top tech gurus have certainly had their share of flops in both research and commercial offerings, they're looking to make the space elevator one of the many success stories.

The idea of a space elevator, popular fodder for science fiction writers, was brought to the masses by one of the fathers of science fiction, Arthur C. Clarke in a 1979 book, The Fountains of Paradise.  Since, scientists have begun to understand that the idea has great merit as, unlike most science fiction devices, it does not rely on exotic or undiscovered physics, but delivers very real gains.  Space elevators could take away much of the danger of shuttle launches, and could carry cargo using less than a hundredth of the energy used by a space shuttle.  A space elevator would open civilian space travel, and would allow vast amounts of cargo to be transported in space, paving the way for large space stations or moon bases.

Shuichi Ono, chairman of the Japan Space Elevator Association describes, "Just like travelling abroad, anyone will be able to ride the elevator into space."

Mr. Ono is working with Japan's top researchers to actualize the tech.  The challenge is daunting.  The greatest obstacle is that the elevator will require cables made of composite materials stronger and lighter than any material yet woven.  These cables will be 22,000 mile-long (36,000km) and will be anchored to the ground and to geosynchronous satellites in orbit.  Another key challenge will be developing elevator carriages to ride on these cables.  These carriages must be capable of climbing the cables and be shielded to keep the passengers safe.  According to Mr. Ono, the elevator organization has the support of some of Japan's biggest companies, who are helping to design the carriages.

Japan's experts claim they will soon have a space elevator.  And they claim they will be able to do it on a bafflingly low budget -- a trillion yen ($9.5B USD).  However, the claim is slightly more believable when you consider Japan's leadership in precision engineering and material science.

Japan's big textile companies are focusing on developing mass-producing carbon nanotube sheets and ribbons, which will be a likely candidate for the elevator cables due to their ideal strength, flexibility, and light weight.  Nanotube cables could survive the heat, electrical discharges, and physical collisions that might occur in the atmosphere and at the lower reaches of space.

Yoshio Aoki, a professor of precision machinery engineering at Nihon University and a director of the Japan Space Elevator Association says that the carbon nanotube cable would have to be four times stronger than the strongest nanotubes currently available, which are 180 times stronger than steel.  However, he's confident this strength will soon be achieved as strength has been increased 100 times in the last 5 years.

As to the carriages, Aoki says that he and his colleagues already have plans.  He states, "We are thinking of using the technology employed in our bullet trains.  Carbon nanotubes are good conductors of electricity, so we are thinking of having a second cable to provide power all along the route."

Japan's top researchers are hosting an international conference in November, which they hope to draw up a timetable for the project at.

In the U.S., various private firms have been working on the tech as has NASA, though it has had relatively little progress and is underfunded.  There's a running space elevator competition, but thus far no company has met the basic criteria to be declared a victor.

Comments     Threshold

This article is over a month old, voting and posting comments is disabled

Arthur C. Clarke
By nosfe on 9/23/2008 9:27:58 AM , Rating: 5
i don't want a space elevator, i want to be able to laugh

RE: Arthur C. Clarke
By Hieyeck on 9/23/2008 9:45:59 AM , Rating: 4
+woosh on whoever rated this down

RE: Arthur C. Clarke
By mattclary on 9/23/2008 10:00:59 AM , Rating: 2
Can you explain? I don't know the reference.

RE: Arthur C. Clarke
By nafhan on 9/23/2008 10:04:29 AM , Rating: 5
Clarke said something to the effect of "The space elevator will be built 50 years after everyone stops laughing"

RE: Arthur C. Clarke
By Mitch101 on 9/23/2008 10:17:41 AM , Rating: 5
I don't think they should build it because no one should be forced to listen to "The Girl from Ipanema" that long.

RE: Arthur C. Clarke
By jmtabak on 9/23/2008 10:47:29 AM , Rating: 2
How does a geosynchronous satellite stay in orbit when there are tons of weight pulling it down? I mean this thing is supposed to be able to lift space ships?

RE: Arthur C. Clarke
By FITCamaro on 9/23/08, Rating: -1
RE: Arthur C. Clarke
By rtrski on 9/23/2008 11:49:17 AM , Rating: 5
I hope you were joking?

The cables ARE "dangling from space". That's why they need incredible tensile strength. The concept works because the center-of-mass of the entire elevator system is at geostationary orbit. How to achieve that is a matter of different options (a countermass in higher orbit to counteract the weight of the cable is the usual proposal I've seen)

RE: Arthur C. Clarke
By masher2 on 9/23/2008 11:04:35 AM , Rating: 5
For most proposals, the tower is constructed substantially beyond geosynchronous orbit. Since the tower constrains the counterweight to move at geosychronous speeds, there is a substantial centripedal acceleration generated, which counteracts the force of gravity on the cable.

RE: Arthur C. Clarke
By Sanity on 9/23/2008 11:10:11 AM , Rating: 2
There would actually be a counterweight that was in orbit out past the geosynchronous point. This counterweight would be actively pulling up on the cable, balancing out the system. As to the weight of the cargo as it's in transit, I don't know how that would be dealt with.

RE: Arthur C. Clarke
By boogle on 9/23/2008 11:52:09 AM , Rating: 2
Its more likely to be a case of what's holding it down?

Remember the Earth is spinning, which means the satellite will actually be pulling away from the Earth. Assuming the satellite has sufficient mass, I would imagine you could pull up some pretty heavy weights.

If they use some sort of magnetic lift (rather than pulling on the cable itself with wheels), I'm guessing the weight that could be lifted into orbit would be pretty extortionate. Of course the power requirements would be equally extortionate - but nothing on the scale of a rocket launch.

RE: Arthur C. Clarke
By masher2 on 9/23/2008 12:00:21 PM , Rating: 2
There's actually a similar proposal which involves making the cable hollow, like a giant straw. Put it in the ocean, and centripedal force pulls water up and out the tube, generating massive amounts of power.

RE: Arthur C. Clarke
By Sanity on 9/23/2008 12:18:34 PM , Rating: 3
Whaaa???? You ever heard of a vacuum? Water can only be pulled so far even out of a well before the weight of the water pulls down and creates a vacuum at the top. Then you need a pump at the bottom to push it up.

RE: Arthur C. Clarke
By jimbojimbo on 9/23/2008 1:25:14 PM , Rating: 2
Also, have these people heard of something called gravity?? Centripedal force is what counters the gravity and thus keeps a satellite in orbit.

RE: Arthur C. Clarke
By masher2 on 9/23/2008 1:42:30 PM , Rating: 2
Maximum suction head is indeed only about 10 meters-- but you don't "suck" water along the entire tube. You generate positive pressure at the bottom. Once the water passes the geosychronous point, you can regain the energy you spent pumping, plus all the potential energy the water contains from the earth's rotational velocity.

RE: Arthur C. Clarke
By Sanity on 9/23/2008 2:19:05 PM , Rating: 1
AANNDD, you get a set of nifty new rings!!! Who needs Saturn!

On a serious note, if you could pump water 26,000 miles against gravity, to regain all of the energy you'd probably have to make the tube a lot longer than necessary for just a lifting elevator. Not to mention needing either an insulated or heated tube. If your pump breaks, I guarantee your tube explodes.

No intention to argue here. I do think it's a pretty ridiculous idea. No offense.

RE: Arthur C. Clarke
By masher2 on 9/23/2008 2:22:31 PM , Rating: 2
It's not my idea, so no offense taken. I first read of it in a technical journal a couple decades ago.

RE: Arthur C. Clarke
By bobsmith1492 on 9/23/2008 2:26:58 PM , Rating: 3
Plus we'd be slowing down the rotation of the earth... in my opinion that would be a much greater threat to the longevity of the planet than global warming or whatever the latest fad is.

Hmm, would it be taking away from the earth's angular momentum to lift things up the elevator? Granted it would be a drop in the bucket but I'm just curious to know.

RE: Arthur C. Clarke
By winterspan on 9/24/08, Rating: -1
RE: Arthur C. Clarke
By masher2 on 9/24/2008 10:27:45 AM , Rating: 3
> "You do understand that there is a complete scientific consensus..."

Quoting Wikipedia on global warming is like quoting your Aunt Mabel on cancer research. With the number of AGW alarmists who also happen to be Wikipedia administrators, the chance of correctness, balance, or neutrality is nonexistent.

While there is nearly a complete consensus that the Earth has warmed somewhat in the past 150 years, the notion that it will continue and lead to devastating consequences is not one shared by most scientists, even among IPCC expert reviewers themselves.

RE: Arthur C. Clarke
By Visual on 9/25/2008 7:30:09 AM , Rating: 2
Preservation of momentum, yes.
But a conventional launch affects the rotation of the earth just the same as a launch using the space elevator, so this is no argument against the space elevator concept itself, rather against space travel in general.

Concerns about linear momentum changes are probably the most easily calmed down. Over time we will likely be launching stuff in many different directions, not one certain direction exclusively, so on average the momentum changes will be canceling each other out.

Angular momentum changes can not be negated by launching things evenly in all directions - any launch will be slowing earth down. But we will not be exclusively launching stuff away... I guess most of that stuff will eventually be coming back - and with it, the momentum of the earth will be returned to its original value. Though there is also the other possibility - we may start importing more materials from space(mining other planets or asteroids etc) than we actually launch, and increase the rotation of the earth.

It will not be just momentum that is changing though - the mass of the earth will change too, in a similar proportion. And here is where it should dawn upon even the most extreme "environmentalists" opposing space travel because of such concerns - even "a drop in the bucket" is a considerable overstatement of the extent of any effect we can possibly have. The mass of earth is 5.9742*10^24, it is so much bigger than what we could launch over even thousands of years that it is completely ridiculous to be concerned about it.

RE: Arthur C. Clarke
By foolsgambit11 on 9/23/2008 1:17:32 PM , Rating: 5
Yes! And we could funnel sea water out into space, thereby preventing sea level rise from global warming! Two birds! One stone! Huzzah!

RE: Arthur C. Clarke
By dflynchimp on 9/23/2008 4:39:23 PM , Rating: 3
we get the same effect using Combine technology ;)

RE: Arthur C. Clarke
By PhoenixKnight on 9/24/2008 2:04:35 AM , Rating: 2
Unfortunately, Combine technology isn't really an option until they can get the LHC back up and running and cause a resonance cascade.

RE: Arthur C. Clarke
By Belard on 9/23/2008 10:26:21 PM , Rating: 2
And can you imagine if OOPS - It won't stop! And we accidently ejected all of our ocean water out into space?

That would suck..

Oh well.. A lot of us hated Free Willy anyways, he can go.

Thing is, the elevator would also generate money with tourist... Charge $10,000 per head to spend a day in space?

RE: Arthur C. Clarke
By MozeeToby on 9/23/2008 1:52:38 PM , Rating: 2
What you're thinking of is called a space fountain but you've got a lot of the details confused.

A station at ground level would shoot water at enormous velocity up the center of the the straw. The water would be moving so fast that it would reach beyond the atmosphere and the kinetic energy of the water is used to hold up the straw the same way a firehose will move around when water is flowing through it (though much more controlled). This way the straw doesn't actually have a large amount of tension or compression at any one point because the movement of the water is holding it up everywhere equally.

Incedently, you don't need to use a liquid. The same thing could be done with chunks of steel the size of boulders or even a single metal bar that could bend back down to your ground station. This would allow you to use magnets to launch, something that isn't possible with water.

RE: Arthur C. Clarke
By masher2 on 9/23/2008 2:01:35 PM , Rating: 2
> "What you're thinking of is called a space fountain but you've got a lot of the details confused."

No, a space fountain is an entirely different type of structure, in which mass is projected upwards to compensate for the structure's lack of tensile strength. The projection system doesn't generate power; it consumes it.

The proposal I mention is a more typical beanstalk, coupled with a form of hydroelectric generating capacity.

RE: Arthur C. Clarke
By gearhead on 9/24/2008 10:38:07 AM , Rating: 2
Instead of water, use liquid hot magma. The specific gravity and viscosity is higher so you could keep the liquid from traveling at enormous velocity. Sure, you'd have some gnarly temps to contend with, but just think: instead of a space fountain, you could have a SPACE VOLCANO. This, in turn, could be used to create a "terra somewhat infirma" in orbit where we could build space strip malls, space mega-theatres and space theme parks.

Wait! -- I've got Disney on line two -- gotta run...

RE: Arthur C. Clarke
By Smilin on 9/23/2008 3:33:46 PM , Rating: 2
If that were possible you wouldn't need a tube. The Earths water would just fly upwards on its own and out into space. This clearly doesn't happen. Perhaps I'm not understanding you.

Regarding the "what holds it up" question . Yes, you stick a counterweight up in geosynchronous orbit. The problem is it would eventually get pulled down. An elevator climbing the cable cannot "push" on the cable (exerting it's opposite force on the earth), it must "pull" on the cable and therefor drag the counterweight downward. This won't pull it out of the sky at first..just speed up the orbit and break the anchor free.

This is the magical part that we are decades away from figuring out... To keep the thing in orbit you have to send mass back down the elevator. Where do you get the mass? Well most of it comes in the form of whatever went up there to begin with right? Unfortunately there is energy loss involved so at some point you're going to have to go into space and retrieve material to send back down. Mining an asteroid is one see where this is going though..we are DECADES away. People have stopped laughing but there are still 50 years to go :P

One other thought.. the space elevator doesn't have to be geosynchronous and it might be better if it weren't. Geosynchronous is waaaay up there. Part way to the moon in fact. I've heard this project described as similar in scope to building a golden gate bridge all the way around the equator.

A better idea would be a "space wheel". Tether a space elevator to a mass that is below geosynchronous. It would move in orbit of course but what you do is then put elevators hanging from the mass that spin in the opposite direction. The net result would be like a spoked wheel (without just the spokes, not the outer rim) rolling around the earth. Instead of anchoring the spokes to the ground like the space elevator you just dangle them into the upper atmosphere.

At the point where the "spokes" make contact the relative velocity would be very low. Low enough to latch a high altitude aircraft to. When the spoke rotates away it pulls the aircraft up into space with it. The time to perform the dock would be several minutes. If anything goes wrong and the dock misses you've got a long time to sort out a glide or parachute return.

The "what holds it up" problem still applies though. Eventually you have to send some mass down or the whole thing loses energy from pulling things up. It then falls out of orbit.

RE: Arthur C. Clarke
By masher2 on 9/23/2008 3:43:26 PM , Rating: 2
> "Yes, you stick a counterweight up in geosynchronous orbit. "

No, no, no. Such a system wouldn't work at all. The counterweight has to be well *beyond* geostationary (not geosynch) orbit. What's at the geostationary point is the center of mass for the entire system.

Yes, a climber rising 'pulls down' on the entire system. But the counterweight doesn't descend to a lower orbit because it's not *in* a free falling orbit. It's constrained to rotate at geostationary speeds though in a higher orbital plane. That centripedal force is countered by the tension in the cable.

There's no need to "send mass down" the cable and, yes the system needs to pass through geostationary orbit to work.

RE: Arthur C. Clarke
By inighthawki on 9/23/2008 11:57:34 AM , Rating: 2
Remember, when the satellite is orbiting in space, it has a velocity counteracting the centripetal acceleration pulling it back to the ground.

RE: Arthur C. Clarke
By masher2 on 9/24/2008 12:26:54 AM , Rating: 2
That's in reverse. The velocity generates a centripetal force which counterbalances gravity pulling it to the ground.

RE: Arthur C. Clarke
By nosfe on 9/23/2008 10:04:34 AM , Rating: 3
“The space elevator will be built about 50 years after everyone stops laughing.”

-Arthur C. Clarke

its one of the quotes that appear at the bottom of this site

RE: Arthur C. Clarke
By TheOcho on 9/23/2008 10:55:15 AM , Rating: 2
+1 awesomeness

RE: Arthur C. Clarke
By luseferous on 9/23/2008 1:20:16 PM , Rating: 2
Anyone interested in this stuff the (scifi) book "the web between the worlds" published 1980 is worth a read. While not the best story in the world the descriptions of the elevator and the problems that need to be overcome in its construction are very good as I remember. Carbon fiber knitting, self replicating machines and superconductivity get a reasonable going over. The giant squid is less plausible however ;)

It was written by Charles Sheffield who I believe has a proper science job in related fields.

RE: Arthur C. Clarke
By luseferous on 9/23/2008 1:32:15 PM , Rating: 2
[edit] Charles Sheffield died in '02 so should read: had a proper science job...

RE: Arthur C. Clarke
By rcc on 9/23/2008 5:49:11 PM , Rating: 2
That whole, flying the cable down to it's anchor thing was spooky as hell. And I'm relatively fearless.

Be cool to watch tho.

Still Skeptical
By MrPickins on 9/23/2008 9:39:14 AM , Rating: 2
I still don't see this being built anytime soon, mostly because I'm still doubtful about our ability to develop and produce a suitable tether in the near future.

RE: Still Skeptical
By Misty Dingos on 9/23/2008 9:57:39 AM , Rating: 2
Like all paradigm breaking concepts, it is not real to people until they see it done. I am certain that if you had been around during 1895 and someone said that people would fly over the Rockies in machines in 30 years you would have laughed in their face. This is not meant to be insulting. There are many people that simply can not accept the space elevator concept. It isn't a failure of intellect it is a failing of imagination.

While the SE has serious technological issues to resolve, they are simply that technological issues. It can be done. It is only the state of today’s technology that prevents it. Technology that can be improved or invented to allow the SE to work.

RE: Still Skeptical
By MrPickins on 9/23/2008 10:20:36 AM , Rating: 2
I never said it couldn't be done, only that the technological hurdles are greater than we will overcome in the near future.

Seems it's mostly dependent on the pace of nanotube development.

RE: Still Skeptical
By 3DoubleD on 9/23/2008 10:32:50 AM , Rating: 5
I have competed in the Space Elevator 2010 Games ( for two years and I can tell you now that the dream of a real space elevator is much further off that $9.5 Billion. A quick list of things that must be overcome:

1) Cable strength - despite what this article says, we are no where close. The best cable candidate at last year's competition was from MIT and was 100% carbon nanotube (the first of its kind) and it performed horribly (although the real marvel was that they were able to make it, a huge first step). As for the 36000 km cable (which is incorrect by the way, the cable will need to be much longer even WITH a large counter weight) see papers such as this one about why initial cable strength estimates were naive.

2) Powering the climber - How do you lift a 20 ton climber? Contrary to this article, suspending a second cable that is not used for structural support would place a massive load on the structural cable. Additionally, what kind of resistive losses do you think you get on a 36,000km cable? Combustion engines or nuclear power plants both fail as the atmosphere thins and heat exchangers can only cool via radiation. What is left? Microwave transmitted power? Good for reasonable distances, but certainly not 36,000km, a collimated beam is needed. Since Masers aren't currently capable of high powers, visible light lasers with PV cell arrays are the best hope at powering such a climber. Even this method suffers when the atmosphere thins as PV cell efficiency falls with temperature.

3) Targeting the climber - Now that we have identified which power source is required, there is the problem of targeting the climber with a high powered laser. One might suggest ultra accurate GPS devices, good to a few centimeters, but you must also think about how you plan on physically directing the beam. Just at 1 km the resolution required is vanishingly small requiring piezoelectric devices. What about 1000km? What about 10000km?

I'm just scratching the surface, there are several of other problems to be dealt with. Are they show stoppers? Probably not. Will they take time to figure out? Definitely. Will it be done for $9.5 Billion? Hell no.

RE: Still Skeptical
By masher2 on 9/23/2008 11:02:25 AM , Rating: 4
> "nuclear power plants [fail] as the atmosphere thins "

Eh? Did you mean to type that? It's not correct...and you wouldn't need to site a nuclear reactor on the cable anyway; it can be put on the ground and power transmitted up. A RTG ("nuclear battery") is a second option, and would be compact enough to mount on the climber itself.

> "Additionally, what kind of resistive losses do you think you get on a 36,000km cable?"

For an HVDC-powered cable, about 290%. Meaning you'd need 3 times as much power as pure lifting cost would suggest -- but that still remains a couple orders of magnitude less than what rocket-based approaches uses.

Of course, if the climber uses its own power source, those losses go away.

> " there is the problem of targeting the climber with a high powered laser"

Why would you need to direct a laser to the climber? You've got a fixed structure. That can contain all the cabling required.

> "which is incorrect by the way, the cable will need to be much longer even WITH a large counter weight"

Not necessarily. Assume enough compressive strength, and one could build one that stretches only to geosynchronous orbit, Most proposals do indeed go far beyond that. But the point you're missing is they do so because its simpler than building a shorter cable. The highest stresses occur at the geosynchronous point, so if you can build one that long, it's not difficult to build one much longer.

RE: Still Skeptical
By 3DoubleD on 9/23/2008 11:31:33 AM , Rating: 4
The problem with a nuclear reactor on the climber is heat. As you well know, conventional nuclear reactors must exchange heat with the atmosphere to operate. When there is no atmosphere to exchange the heat with only radiative heat transfer will be available. However, I completely agree that using a nuclear reactor on the ground and transmitting it up is a great idea.

I'm not sure where you get this 290% figure. A quick google search reveals traditional HVDC lines have 3% loss per 1000km. The real problem is that a carbon nanotube line isn't a traditional HVDC line. Single carbon nanotubes have demonstrated ballistic electron transport abilities, however, a carbon nanotube cable isn't one 36,000km nanotube, it's almost infinitely more. I did a quick search for the transmission qualities of carbon nanotube materials, but didn't turn up much (but it was a very quick search).

Please don't tell me 36,000km cable is a fixed structure. Even skyscrapers move on the order of several meters in the wind. This cable will have natural resonances and will be enduring a very dynamic environment.

You are correct about not needed to reach 36,000km, but I can't think of a good reason why you would want it shorter unless you like making things more difficult (and less useful).

RE: Still Skeptical
By masher2 on 9/23/2008 11:42:52 AM , Rating: 2
> "I'm not sure where you get this 290% figure. A quick google search reveals traditional HVDC lines have 3% loss per 1000km"

From that figure: 1.03^(36000/1000) = 290%.

> " conventional nuclear reactors must exchange heat with the atmosphere to operate"

They need to exchange heat with something . Why not the cable itself? Carbon nanotubes are typically excellent coonductors of heat, and you don't need to dissipate megawatts of power. The suface area of the cable should be an excellent radiator...and as heat flows down the cable to the atmosphere, convective loss can take place as well.

But I agree that transmitting up power would likely be more cost-effective.

> "Please don't tell me 36,000km cable is a fixed structure"

It's fixed in relationship to the climbers themselves, just as a bridge or skyscraper (both of which sway themselves) are fixed to the cars or people within them. There shouldn't be any problem mounting cables on the ribbon.

> "but I can't think of a good reason why you would want it shorter unless you like making things more difficult "

That was my point. You seemed to be suggesting that the cable would need to be longer, and that would complicate the task. I was merely pointing out its actually simpler to use a longer structure.

RE: Still Skeptical
By tyanlion on 9/23/2008 12:29:15 PM , Rating: 2
professional and serious comments about tech issues are the reason for me coming to the site. good job i enjoyed understanding what were the limitations to this exercise. hopefully whatever theory they put into practice it will work out. I really do want to know that if it will be my life time that space will become a reality for all mankind

RE: Still Skeptical
By tyanlion on 9/23/2008 12:34:26 PM , Rating: 2
btw is anyone able to tell me how long it would take to get to the top with the best available technology?

RE: Still Skeptical
By dubldwn on 9/23/2008 1:11:45 PM , Rating: 2
22,000 mi / 200 mph (?) = 110 hrs = 4.6 days.
meh, if you take the Japanese one I'm sure they'll have cool things to look at.

RE: Still Skeptical
By sebor on 9/23/2008 6:11:48 PM , Rating: 2
OK I would be more than happy with 200 mi. So, few hour trip would be enough to drink a cup of coffee in space.

Also, it would probably be much cheaper than a cup of coffee on 22000 mi.

RE: Still Skeptical
By 3DoubleD on 9/23/2008 2:11:46 PM , Rating: 2
It is highly unlikely that the strongest material ever made by humans will also be the greatest conductor ever made by humans. This means you will need to hang a power cable separate of the structural ribbon (note, the carbon nanotube cable will actually be a ribbon for numerous reasons, consult literature for more details, this website gives brief details ). If you attempt to use a power cable, this design will ultimately fail as it would need to be nearly as strong as the structural ribbon to not break (the load difference would actually be the weight of the climber).

For example, carbon nanotubes have a resistivity on the order of 10^-4 ohm*cm. Aluminum has a resistivity of 2.82×10-6 ohm*cm. So while carbon nanotubes are conductors, they aren't nearly as good as traditional transmission line conductors. You would need to transmit thousands of percent more power than you need.

If you use anything other than a super high strength material, aluminum for example, it will fail under its own weight. If you affix it to the ribbon (I'm not sure how you would do that without introducing stress concentration points that would certainly lead to failure) you have to increase the strength of your ribbon material such that it can hold both its own weight and the weight of the aluminum cable (which would probably weigh more than the ribbon itself)

Carbon nanotubes are certainly excellent conductors of heat, however, how do you propose heat sinking a climber moving a 100km/h (15 day trip to geosynchronous orbit) to an almost paper thin ribbon in a way that will not damage the surface? Neglecting aerodynamic drag and rolling resistances, how much power does the climber need to ascend?

P=mass*gravity*height/time=20000kg*9.81m/s*27.7m/ s= 5.4 MW

If we assume an outrageous 50% efficiency, that is 5.4 MW of heat to dissipate into the ribbon without a good thermal contact!

I also never said transmitting power up the cable would be more cost-effective. We also had a miscommunication regarding the fixed structure comment. I was referring to targeting the climber with laser for power transfer. You still don't understand that you won't be mounting any cable though. There will be no where to mount. The cable will be a thin ribbon up to a few meters wide in places (width varies with elevation to maintain constant stress, the most efficient design). It won't look anything like a building.

We also got mixed up with the length of the tether. It has to be at least the height of geosynchronous orbit, but to reduce the size of the counter weight it should be a bit (several thousand km) longer. I have never meant to say anything else. I was only correct the article, not pointing out it made the task more difficult. So I think we are in agreement here.

Here are a couple more brief answers, however, I'd recommend finding some good journal articles. While perhaps not the most unbiased author, look up Dr. Brad Edwards, he was responsible for reviving the idea of the space elevator after carbon nanotubes were discovered.

RE: Still Skeptical
By masher2 on 9/23/2008 3:12:39 PM , Rating: 2
> For example, carbon nanotubes have a resistivity on the order of 10^-4 ohm*cm"

No. CNTs exhibit very strange electrical properties, and can be either semiconductor or conductors much better than copper, based on changes to chirality or doping properties. See this paper:

> "If you attempt to use a power cable, this design will ultimately fail as it would need to be nearly as strong as the structural ribbon to not break "

You mate it to the structural ribbon. It then need not support its own weight, but rather simply the torsional and bending stresses from oscillations.

> "that is 5.4 MW of heat to dissipate into the ribbon "

I was assuming a much lighter climber. If we have cheap, high-strength CNTs, one should be able to build such a climber with a mass of just a hundred kilos or a couple metric tons of cargo.

The real issue is reactor weight though, I agree...which is why transmitted power is probably a better option.

> "You still don't understand that you won't be mounting any cable though. There will be no where to mount"

If you don't have a mating (be it mechanical, electrical, or magnetic) between the climber and the cable, then you don't have a space elevator. As I'm sure you know, the concept requires lifting against the cable to even work.

RE: Still Skeptical
By 3DoubleD on 9/23/2008 4:19:59 PM , Rating: 2
I referenced that value, it may have been for the semiconducting nanotubes, but last I heard they were still having trouble growing only metallic wires anyways. You can purify a batch of semiconducting carbon nanotubes but the reverse isn't true.

The best resistivity I have found was ~5x10^-6 for a single wire. The ribbon will not be a single wire though, it will be a 10^40 (or something astronomical) wires. The conduction values will get much worse before they get better for a real material. One interesting thing I did learn during this search was that resistivity drops with increasing temperature up to a limit.

You mate it to the structural ribbon. It then need not support its own weight, but rather simply the torsional and bending stresses from oscillations.

I've already responded to this, but perhaps I should be more clear. The ribbon will appear like a woven piece of fabric meters in width but millimeters in thickness. The climber will ascend using rollers, tensioning the ribbon locally to stay attached. There are numerous examples of this on the Internet. Check out pictures of these competition climbers:

Plus, if you attach more weight to the cable you have to increase the ribbon's strength to weight ratio even more! We are already hard pressed to make a ribbon that can hold itself up! I hope it's clear now why we can't mount things on the ribbon unless it supports it's own weight.

If you make the climber lighter, you may get some of the heat issues. This is where the transmitted power via lasers and PV cells comes in. Under concentrated monochromatic light, PV cells can reach near 50% efficiencies, so with a 20 ton climber we would have an identical heat dissipation problem as discussed before. Decrease the cargo capacity of the climber such that the heat can be properly dissipated then you have a feasible design. Running many smaller elevators would probably work better than one large elevator.

If they manage to make a super strong carbon nanotube cable that can conduct at the level of copper (or an order of magnitude close to it) then that could make this easier, but there is no guarantee that will happen. Even then, there are already problems with a neutral cable traversing the various layers of the atmosphere and not getting struck by lightening (which would definitely damage the cable, how much, who knows). I couldn't imagine a 100 kV cable attracting much electrical attention from the atmosphere.

Who knows what technologies will unfold in the future, but I'm very sure that $9.5 billion won't solve anything in the short term.

RE: Still Skeptical
By masher2 on 9/23/2008 4:40:52 PM , Rating: 2
> "if you attach more weight to the cable you have to increase the ribbon's strength to weight ratio even more!"

Any practical elevator cable is going to be far more massive than a climber. The parasitic weight on the cable is therefore going to be a small fraction of the total system mass, unless one assumes a large number of simultaneous climbers.

As for heat dissipation, remember that, once one exits the atmosphere, drag is no longer a problem. There's therefore no reason a massive (in area, not weight) radatior couldn't be unfurled.

RE: Still Skeptical
By 3DoubleD on 9/23/2008 5:17:40 PM , Rating: 2
Any practical elevator cable is going to be far more massive than a climber. The parasitic weight on the cable is therefore going to be a small fraction of the total system mass, unless one assumes a large number of simultaneous climbers.

That is not what I am referring to. The weight of the climber is negligible. If you hang a power cable, that is not negligible as it would weight as much (or more) than the ribbon itself. The only structural component that can exist between the ground and orbit is the super strong cable, 36,000km of power cable would be too heavy. That is my point.

The radiator is a great idea though.

RE: Still Skeptical
By Ajax9000 on 9/24/2008 12:33:03 AM , Rating: 2
Masher made a good point re an unfolding ratiator, but change the thinking and you can simplify the problem -- have an unfolding microwave rectenna.

Using the counterweight at GEO as the source for a set of maser/phased-array-microwave power beams, power is beamed to the climber down parallel to the cable. Tracking shouldn't be particuarly important when "shooting down the wire". In fact a slightly diffuse beam helps -- a highly collimated optical beam needs to be accurately tracked for each climber, a slightly diffuse beam could be used by all the climbers as no one climber should shadow all the others.

For the first ~100 km of the trip the rectenna can't be used, so have a power cable from the ground up.

In summary, wired power up to ~100 km, beamed power down for the remaining 35,900 km.

There is no need for a power cable 36,000 km long.

RE: Still Skeptical
By Kugar on 9/23/2008 6:38:41 PM , Rating: 2
"I'm not sure where you get this 290% figure. A quick google search reveals traditional HVDC lines have 3% loss per 1000km"

From that figure: 1.03^(36000/1000) = 290%.

I think your math is wrong as losses can not exceed 100% (unless you are comparing against something other than the power generated)
Focus on the 97% power transmission rate instead of the 3% loss rate (per 1000 km)
So the power that gets succesfully transmitted is
0.97^(36000/1000) = 33%
And the power lost from resistance is
1 - 0.97^(36000/1000) = 67%

Yet somehow you arrived at the correct conclusion
i.e. that a ground based power plant would need to generate 3x the power required by the climber.
Actually that is only true when the climber reaches full altitude. As it climbs through lower altitudes, the electrical path distance and hence the resistive loss would be less.

RE: Still Skeptical
By masher2 on 9/23/2008 7:46:08 PM , Rating: 2
> "Yet somehow you arrived at the correct conclusion"

Because I wasn't calculating the loss factor, but rather the amount of power required over the base value.

RE: Still Skeptical
By drank12quartsstrohsbeer on 9/23/2008 5:02:53 PM , Rating: 2
How about a super mega gigantic solar array as the counterweight? It could generate its own power then.

RE: Still Skeptical
By ArcliteHawaii on 9/24/2008 8:41:43 PM , Rating: 2
Couldn't you combine electrical with chemical rockets to move the space elevator? You could use electric engines for the first few thousand miles. Then far from the gravity of the earth and friction of the atmosphere, you could fire up chemical rocket or ion engines to power it the rest of the way.

RE: Still Skeptical
By Zoomer on 9/27/2008 9:06:40 PM , Rating: 2

RE: Still Skeptical
By BruceLeet on 9/23/2008 6:16:10 PM , Rating: 1
Wait a minute, why do we have to use cables? Now THATS laughable.

Why not use magnets? MagLev?

RE: Still Skeptical
By FITCamaro on 9/23/2008 11:08:43 AM , Rating: 5
Chuck Norris will stand underneath the climber after its loaded and stare at it until it moves into space on its own trying to get away from the glare.

RE: Still Skeptical
By mrteddyears on 9/23/2008 11:15:46 AM , Rating: 2
3DoubleD can travel in time how cool !!!

RE: Still Skeptical
By chris2618 on 9/23/2008 12:37:00 PM , Rating: 2
i would say one of the big problem is life support. Until you get to a few thousand feet you can use the air outside but after that you will have to have carbon dioxide filters and oxygen. not only that you need the life support systems for the satellite.

I don't think they is an efficiency problem with pv due to lower temps because they work on a variation of the photoelectric effect which i don't think is temperature dependent.

RE: Still Skeptical
By 3DoubleD on 9/23/2008 2:22:58 PM , Rating: 2
Life support is a huge issue as well. Breathable air will have to be carried along as well as food and water. Another important factor is radiation. Cosmic ray exposure is rather significant at certain altitudes. Astronauts traveling by rocket travel through these regions very quickly resulting in reasonable doses. This would not be the case for people on a space elevator. I would imagine the space elevator would be best used for a cargo hauling device as it can very efficiently haul cargo up without any life support systems while people an take rockets. A rocket would be much faster as well.

Solar cells don't operate via the photoelectric effect. In a PV cell, electrons are removed from an atom across a bandgap by absorbing a photon. This electron goes into the conduction band of the semiconductor and may be captured in a circuit. However, the electron may not escape the semiconductor and could recombine. The recombination rate increases with temperature. Overall semiconductors are very temperature sensitive (just think of your cpu and whether you would pull your heat sink off while running it).

RE: Still Skeptical
By ianweck on 9/23/2008 4:14:49 PM , Rating: 2
i would say one of the big problem is life support. Until you get to a few thousand feet you can use the air outside but after that you will have to have carbon dioxide filters and oxygen. not only that you need the life support systems for the satellite.

This type of thread is why I like coming to DT. Very little BS arguing/name calling etc.

Regarding the life suport question, my opinion is that we probably should design the elevator for freight only until we start on rev.2. Unless some breakthrough is made that will make hauling around life support a moot point. Is that practical (as far as space elevators go)?

RE: Still Skeptical
By masher2 on 9/23/2008 4:23:42 PM , Rating: 2
One of the nice things about the space elevator concept is that different crawler types can be cheaply and quickly customized to fit individual needs. There's no reason we can't start with slow-moving, unshielded cargo containers, then add in units specialized for heavy lifting, personnel carriers, or even eventually much more massive units containing luxury accommodations.

There's a constraint on total mass on the system, of course, and a smaller constraint on how fast mass can be raised (lifting causes a small degree of deflection) but switching in and out customized climbers should be quite easy.

RE: Still Skeptical
By Chocobollz on 9/30/2008 12:32:54 AM , Rating: 2
They solve the problems, IF they're smarter than you my friend ;-)

Terrorist's Dream...
By Ctsephion on 9/23/2008 10:03:31 AM , Rating: 1
This is going to be no doubt the biggest target in the world for when an organization wants to make a name for themselves (assuming it's ever built). Want to show the world how serious you are in your crusade/jihad/campaign/mission? Just take down the tallest and most expensive structure(?) in history...

RE: Terrorist's Dream...
By GaryJohnson on 9/23/2008 10:11:58 AM , Rating: 5
You're right: we should never do anything amazing, revolutionary, or wonderful because someone will probably try to destroy it.

RE: Terrorist's Dream...
By Ctsephion on 9/23/08, Rating: -1
RE: Terrorist's Dream...
By MrJim on 9/23/2008 1:51:17 PM , Rating: 2
Instead, TO BE SAFE, we will start to live in caves and abolish rule of law. To be safe. Yes. Like them terrorists everywhere!

RE: Terrorist's Dream...
By JediJeb on 9/23/2008 10:42:30 AM , Rating: 3
If someone cuts the cable it would be a setback but probably not destroy everything. The upper platform would be a GEO satelite and if the cable was severed would remain in orbit. The cable would probably need to be detached at the top to reduce atmospheric drag but if the upper platform has its own power supply it could remain active until another cable could be sent up or down to reconnect to the surface. Loss of a carriage in mid transit would be the worst danger from an attack, but the addition of parachutes could probably protect it.

Of course this is only the things that are popping into my head as I think of possible outcomes, but I think it is what we need to do to make this a reality. Dream up the idea and test it with computer modeling, set the specs and go with it. Stop sitting around or sending rubber duckies out to discover what has already been answered. If people spent as much time figuring out how to do this as they do figuring out who will be the next American Idol it would already be finished.

RE: Terrorist's Dream...
By Hafgrim on 9/23/2008 1:29:55 PM , Rating: 2
As this space Elevator seems to be based out in the ocean it would most likely have a HUGE & strictly enforced no fly/boating zone around it. This would make it completely safe and easy to protect from just about anything & everything except the super power Nations which would want to take part in using it & helping to protect it... IT would be un attackable and totally safe. I say let japan have it, USA dosnt have to be the leader of EVERYTHING and we will be glad to rent time on it. '=)

RE: Terrorist's Dream...
By masher2 on 9/23/2008 2:07:03 PM , Rating: 5
> "I say let japan have it, USA dosnt have to be the leader of EVERYTHING "

If the US attempted to build such a structure, the first twenty five years would be squandered in environmental impact assessments and legal challenges from environmental groups.

Our days of heading large projects seem to be over. In less time than the US has spent just talking about the Freedom Tower replacement for the WTC, the much taller and larger Burj Dubai has gotten built entirely.

RE: Terrorist's Dream...
By Master Kenobi on 9/23/2008 2:26:12 PM , Rating: 1
Sad but true. Until we learn to squash the environmental groups we will never be able to do anything large scale ever again.

RE: Terrorist's Dream...
By Spuke on 9/23/2008 3:21:09 PM , Rating: 1
Our days of heading large projects seem to be over.
Once we're gone, they'll just move on to the next target. One by one until we're ALL living in caves under their control (of course), bartering for broccoli.

RE: Terrorist's Dream...
By hellokeith on 9/23/2008 4:23:10 PM , Rating: 3
Our days of heading large projects seem to be over.


You & I have disagreed often on NASA rocket & ISS topics. But I think Hafgrim makes a good point, that the US does not need to be the leader (especially monetary-wise) on every massive scientific undertaking. The LHC is a fine example of a large project which happily can take place outside of the need for US funding. And the space elevator can be another. NASA is dedicated to flight, which is a very different discipline than building skyscrapers. We gladly ferried the Japanese Kibo module up to the ISS (along with a Japanese astronaut). In 30 (?) years when the Miyagi Space Elevator opens, the Japanese can repay the favor and haul up some US orbital solar collectors.

RE: Terrorist's Dream...
By masher2 on 9/23/2008 4:44:37 PM , Rating: 3
To clarify, while I certainly bemoan the US's decreasing desire to improve humanity through large civil engineering projects, I will be ecstatic if Japan (or any other nation) actually builds a space elevator.

RE: Terrorist's Dream...
By androticus on 9/24/2008 9:29:51 PM , Rating: 2
All it would probably take would be a small plane loaded with explosives to fly up to the cable and detonate. Even a drone powered by remote control would work. I find it difficult to imagine how a huge area of the sea could be effectively patrolled to keep out boats. Maybe the terrorist vulnerability could be addressed, but I bet it will be half the technological battle.

As for the previous poster saying a cut cable would be no big deal, uh... DUDE do you even understand how this thing works? The counterweight would NOT be in geosynchronous orbit (maybe a module could be there) -- it has to be further. And if the cable breaks, goodbye counterweight, and goodbye cable. In fact, if they put a station (they'd have to, else why build the damn thing!) at geosync, then the system would necessarily have to have an emergency cable detach mechanism that would simultaneously detach both the earthward and spaceward cables, to keep the whole thing balanced (the station would be ok, remaining in orbit.) Back on the ground, say hello to several tons of cable coming crashing down!

It is a neat idea, but seems too fragile to be practical.

RE: Terrorist's Dream...
By Zoomer on 9/27/2008 9:15:08 PM , Rating: 2
It can certainly be engineered to take a certain amount of damage and not fail. One thought would be the immediate detachment of all travelling loads when it is damaged. They can float down or stay up there for a little bit. Way better than the cable crashing down, imo.

It wouldn't be too hard tracking an open area. I bet the US military already has the capability, or have ready to build plans for such systems. High powered radar, SAM sites, etc. No fly zone of 500 miles, and anything gets closer than 50 miles == blown away.

Seems doable.

Big problems, but big rewards
By randomly on 9/23/2008 10:18:49 AM , Rating: 4
I'm curious how they will solve the problem of avoiding space junk, since the tether is stationary and everything orbiting the earth below geosynchronous crosses the equator twice an orbit. Impact speeds will be 27,000 km/h. I know it's been proposed to have a floating earth anchor that could be maneuvered around in the ocean to avoid larger trackable space debris, but what of the smaller stuff?

Another big problem is the corrosion from atomic oxygen in the upper atmosphere.

This is very cool news though, because if a workable system can be realized it's going to change everything with respect to usage of space. Space based solar power, exploration/tourism, zero-G manufacturing, etc...

RE: Big problems, but big rewards
By mles1551 on 9/23/2008 10:43:53 AM , Rating: 2
I'm curious how they will solve the problem of avoiding space junk

That will be solved by their next project, building of the Mega Maid. lol

RE: Big problems, but big rewards
By Jimbo1234 on 9/23/2008 1:58:44 PM , Rating: 3
Switch from suck to blow!

RE: Big problems, but big rewards
By masher2 on 9/23/2008 12:21:45 PM , Rating: 2
A laser-based system to "sweep" out debris has been proposed, similar to the one proposed for the space station. You don't need a laser powerful enough to destroy the debris...just to give it a nudge out of the way.

RE: Big problems, but big rewards
By randomly on 9/23/2008 2:36:21 PM , Rating: 2
I don't see how a laser system will work unless it can track and target debris. My concern was for debris that's too small to currently track.

RE: Big problems, but big rewards
By achintya on 9/23/2008 3:25:13 PM , Rating: 2
too small to currently track.

The key word here is currently. What with the space elevator taking a a bare minimum of 5-10 years to make, the technology to do this will also be developed.

RE: Big problems, but big rewards
By randomly on 9/23/2008 5:54:50 PM , Rating: 2
There is a limit to how small the debris that will be detectable and trackable in the next 20 years. Will that limit be small enough that the tether can weather those impacts that do occur from debris below that trackability limit?

It's a fascinating technology, but it remains to be seen if the technical problems can be solved in the near term.

RE: Big problems, but big rewards
By 4play on 9/23/2008 9:49:38 PM , Rating: 2
the same way normal satellites do?

i've seen this before...
By chalupa on 9/23/2008 10:05:03 AM , Rating: 2
..."This is a Nobunaga Hiroichi reporting
rive from hayben. The great a-nation
of Japan reached a-hayben today about
eight o'crock Pacific Standard Time-eh.
Therefore hayben is now a-decrared
an official part of Japan, because we
got a-here first. And now for the weather
in heaben, let's go to Natsako Semu."

RE: i've seen this before...
By fezzik1620 on 9/23/08, Rating: -1
RE: i've seen this before...
By TheDoc9 on 9/23/2008 11:31:50 AM , Rating: 2
I think it's a reference to south park

RE: i've seen this before...
By napalmjack on 9/23/2008 11:32:28 AM , Rating: 2
Have you ever heard of South Park??
How about satire??

RE: i've seen this before...
By abscoder on 9/23/2008 11:55:46 AM , Rating: 2
Did you mom forget to put a sense of humor in your lunch box today? Watch this episode...

RE: i've seen this before...
By mmntech on 9/23/2008 2:19:36 PM , Rating: 2
Some people just don't watch TV. Weird people with sick minds.
Trey Parker's wife if Japanese.

"Todeh weather in hebon, partry croudy."

RE: i've seen this before...
By abscoder on 9/23/2008 3:07:01 PM , Rating: 2
Trey Parker's wife is Japanese

She makes me hot like Nagasaki.

RE: i've seen this before...
By cokbun on 9/23/2008 11:45:01 AM , Rating: 2
Where were you? When they build that ladder to heaven? Ladder to heaven, Ladder to heaven, Ladder to heaven, Ladder to heave~n, nine eleven... I love that episode. :D

An interesting idea
By 325hhee on 9/23/2008 10:22:33 AM , Rating: 2
This is going to be some project, so many things to over come and I hope to be alive to see it. First obstacle, building something higher than the earth's atmosphere, then pressurizing it, and lastly an environmental system to control air, temperature, and possibly gravity?

I hope this will see reality, all the planing and mathematics involved is going to be mind boggling. I'm just wondering, who's going to hold claim to the restaurant on the top? hehe

RE: An interesting idea
By LivingDedBoy on 9/23/2008 11:00:46 AM , Rating: 3

RE: An interesting idea
By JediJeb on 9/23/2008 6:24:27 PM , Rating: 3
Better if it is Taco Bell, then the methane produced can be used for power for the station.

RE: An interesting idea
By LivingDedBoy on 9/24/2008 11:16:15 AM , Rating: 2
But McDonalds has more money than Taco Bell. Plus they could just use the used firer oil for power.

Japan leading in everything?
By bobsmith1492 on 9/23/2008 1:10:40 PM , Rating: 1
I take issue with Jason's comments about Japan leading the US in so many things. Sure, they have lots of gadgets that are more advanced but they use technology developed here. The key is Americans simply don't want as many fancy gadgets (on average) and the population density is too sparse to economically upgrade the infrastructure regularly enough to support said fancy gadgets.

I'd like to see some data backing up the claim of "Japan's leadership in precision engineering and material science" also...

RE: Japan leading in everything?
By jimbojimbo on 9/23/2008 1:46:44 PM , Rating: 3
What does population density have to do with a stereo or cell phone or TV? And population density is always an extremely poor argument if you're referring to bandwidth speeds. Manhattan has a MUCH higher population density and still has crap for bandwidth service. You do realize that there are still rural unpopulated areas in Japan right or when someone says "Japan" all you can think of is Tokyo?

By bobsmith1492 on 9/23/2008 2:35:23 PM , Rating: 2
I AM talking bandwidth - stereos and TVs are old-school.

"In 2005, 44.9 percent of the entire national population was concentrated within a 50-kilometer radius from the centers of the three largest cities of Tokyo, Osaka and Nagoya, respectively (together comprising 6.1 percent of Japan's total land area)"

RE: Japan leading in everything?
By NarcoticHobo on 9/23/2008 8:41:53 PM , Rating: 1
What does population density have to do with stereo, cell phone, or TV? Well here you go:

1) Stereo, basically nothing, but I would hardly call Japan way ahead of us in that tech. Klipsch and Bose are generally considered two of the better speaker manufacturers and they are both US based companies.

2) Cellphones and TV are basically the bandwidth argument. Because of the population density of the US companies are have to spend enormous amounts to upgrade the entire system, sure they could upgrade parts of the system in dense areas, but that means they are basically running two separate systems. Japan smaller size and greater density allow it to perform complete system upgrades in a much shorter time and lower cost than we could ever hope for. Mainly because the systems they have to upgrade are far far less massive.

Once we get the infrastructure updated (IE lay down all those necessary fiber optic cables) then the technology becomes dependent on the relays and routers, which we are by no means slacking on technology wise.

RE: Japan leading in everything?
By MrTeal on 9/24/2008 11:37:49 AM , Rating: 2
Bose? One of the better speaker manufacturers?

Maybe if you watch a lot of infomercials.

By micha90210 on 9/23/2008 2:51:54 PM , Rating: 2
That's maybe about 50,000,000 tons of cable! How are they going to push it all up and connect it with the satelite/s?

By micha90210 on 9/23/2008 2:56:03 PM , Rating: 2
Right, got it, the cable is gonna be solid and they're gonna push it up from earth like a fountain.

By masher2 on 9/23/2008 3:32:29 PM , Rating: 2
In most proposals, the cable wouldn't have enough compressive strength for that. One method would be to run down a hair-thin seed cable from geostationary orbit, then use it to pull up successively larger cables.

By zozzlhandler on 9/23/2008 3:29:50 PM , Rating: 2
Actually, you start at the geosynchronous point and extrude cable outward and inward. This way the structure is in dynamic balance the whole time. When the bottom reaches the earth, you tether it. Of course, then the problem becomes getting all the cable material into orbit...

Anyone interested should also check out ideas such as rotating cable segments (skyhooks) etc.

Going up?
By napalmjack on 9/23/2008 9:48:14 AM , Rating: 2
"5th Floor, Lingerie, Cosmetics, and Lunar Surface."

RE: Going up?
By marvdmartian on 9/23/2008 10:36:57 AM , Rating: 3
The question is, will it be like the Tokyo subway, where the white gloved crowd control cops shove everyone on the train cars?? That'd be one crowded elevator, for sure!!

By edpsx on 9/23/2008 11:00:38 AM , Rating: 4
So if you fart in this elevator, you'd have to smell it for how long exactly?

Talk about losing friends.

By evilharp on 9/23/2008 10:21:16 AM , Rating: 2
If they do build one, a glass floor is a must!

rail gun type launcher
By kattanna on 9/23/2008 12:18:04 PM , Rating: 2
wouldnt it be much more practical, and doable, to build a 20-30 mile long mag lev track that would accelerate payloads to speed to launch into space?

By spagnitz on 9/23/2008 1:22:11 PM , Rating: 2
Best idea may be to build it on a small island right in the middle of atlantic or pacific, surrounded by layers of security.

By crleap on 9/23/2008 3:09:31 PM , Rating: 2
Heaven forbid, that instead of each country using billions or trillions of currency units each, we actually work together and pool innovation to complete one in half the time. We are even pretty good allies with Japan and we still can't work together. Such a sad species is homo sapiens.

RE: unity
By masher2 on 9/23/08, Rating: 0
By Oregonian2 on 9/23/2008 3:46:36 PM , Rating: 2
I dunno. This "race" reminds me of the race to fusion powered spacecraft in the movie "IQ". At this point (I think) we might as well say some of our theoretical string physicists are in the race toward inter-dimentional travel. Let them race for a while, see if they get tired and quit.

I love Japan
By Xs1t0ry on 9/23/2008 6:37:31 PM , Rating: 2
I really hope this works... I want to live to see moon colonization.

By wetwareinterface on 9/23/2008 8:43:26 PM , Rating: 2
why wouldn't you have a hollow tube for the center that flattens out to ribbon material branching to 4 sides for the main "cable"? you get the advantage of being able to run secondary cables up the middle hollow tube. these can act as power to platform point transmitters, as well as secondary anchors. wind shear on 1 of the "ribbon pieces" dimensional sides would mean no loss of climing ability if you make the climber fit onto 2 dimensional sides of the ribbon.

would be an "O" at the center with a cross branching out equally to four sides looking down.

the climber could attach at all 4 ribbons and circumnavigate the whole structure. if you have wind or torsional stress on one side or another the shape of the climber could hold the ribbon positions steady during climb and in severe failure or a rip, the cliber could continue by loosening one set of pinch rollers on the affected piece and still climb.

or another concept is a near circumnavigating climber with a hollow tube at center of the ribbon that is open on one side in a c shape with additional cable in the center. now you have a climber with the ability to attach to a positive and negative voltage source in the cables and also attaches to 3 ribbons for redundancy and additional climbing torque on the pinch rollers like the first 4 way ribbon only you are able to supply voltage through the cable also.

and as far as the spreadable radiator to shed heat make it a balloon at first to lighten the load during atmospheric assent using lighter than air gasses, at space it acts as a radiator for heat.

By CurtOien on 9/23/2008 11:59:46 PM , Rating: 2
I think it would be neat if we could have massive solar collectors in space and send the electricity down the ribbons to earth for terrestrial usage. Why are so many people here apparently afraid of "environmentalists" or of considering our environment when making decisions.

By androticus on 9/24/2008 12:17:19 AM , Rating: 2
(see Subject)

By raaja on 9/29/2008 11:36:02 AM , Rating: 2
I am not sure if we can travel up/down in a reasonable amount of time to make it to the 20000+ miles. There will be some speed limit to protect the cable (*friction, wear/tear, etc). If its going to take 1 month one way, is it really worth it. Another thing to consider: the maintenance needs of this cable.

By UncleSnake on 9/30/2008 5:23:43 AM , Rating: 2
On upon a time, people thought this world is flat and impossible to build the ship from metal.

We cannot talk about future with today mindset and technology.

I think this idea look funny for you because it come from Japanese not from American.

I hope they can do it. And leave you guy feel envy. :-)

Pi in the sky...
By mmcdonalataocdotgov on 9/23/2008 3:09:29 PM , Rating: 1
Anyone? Anyone? Huh!

Well it is. Just make sure those elevator cars are escape pods as well.

By Ammohunt on 9/23/08, Rating: 0
great idea!
By omnicronx on 9/23/08, Rating: -1
RE: great idea!
By Chimpee on 9/23/2008 1:29:43 PM , Rating: 2
Who said their going build this in a fault line, most likely they will build this at a floating structure near the equator.

RE: great idea!
By jimbojimbo on 9/23/2008 1:37:09 PM , Rating: 2
They can't build it in Japan. I'm guessing you didn't read the book and you've no idea about geosynchronous orbit. It has to be basically where the equator is.

RE: great idea!
By jimbojimbo on 9/23/2008 1:48:32 PM , Rating: 2
Dear god, the fact that someone noted your comment worth reading makes me weep for the future.

RE: great idea!
By jimbojimbo on 9/23/2008 1:50:47 PM , Rating: 2
Dear god. The fact that someone actually voted your comment as worth reading makes me weep for the future. I'm just glad you and that person won't have, nor can, any part in the elevator.

"If you can find a PS3 anywhere in North America that's been on shelves for more than five minutes, I'll give you 1,200 bucks for it." -- SCEA President Jack Tretton
Related Articles

Copyright 2016 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki