Space Elevator

Palomar · 2003-09-18 14:19:40

*It's been discussed here before, most notably by Phobos (so missed!), and I tried to dig up an old, relevant thread to affix it to, but the Search feature failed.

I thought this might stir up some renewed discussion.

--Cindy

Shaun Barrett · 2003-09-18 19:53:12

A great link, Cindy! Thank you.
I know this is a subject dear to Phobos's heart. Such a pity he no longer contributes to New Mars.

The space elevator concept appears to be gaining momentum and the hard research into carbon nanotubes seems to be progressing nicely too. I was particularly encouraged by the news from China that it may be possible to fuse nanotubes together without the need for a matrix. From the little I know of this technology, using a matrix dilutes the strength of the finished product. Not having to use one means we should be able to approach or equal the theoretical maximum strength of a carbon nanotube 'ribbon', which means we will have more than enough strength to construct very robust elevator cables.
The biggest problem, apart from the ever-present threat of attacks by ignorant religious zealots, may be the orbital debris we've left cluttering up near-Earth space. Sooner or later, I suppose we can expect an impact on the cable by a chunk of metal travelling at 27,000 km/h!! This is new territory for theoreticians, I should imagine, and samples of the cable will have to be tested in labs to see how they stand up to that sort of collision. If a cable is going to shear through when hit by something, then it may prove impossible from a safety point of view to ever utilise this brilliant new technology. And what a terrible shame that would be!

A more sinister aspect to this story may be the involvement of the U.S. military in the background. If space elevators are going to make space easily and cheaply accessible to all nations and groups, then the American military's plans to dominate the planet by securing monopolistic control of the so-called 'high ground' will be scuttled. There may be moves afoot, as we speak, to simultaneously encourage research and development into space elevators while secretly ensuring that their use is strictly controlled. This would be a tragedy if it were allowed to occur because of the consequences to human expansion into space and because it would give the islamic terrorists a new excuse and a whole new selection of recruits eager to bring the cable down!
I believe moves should be made, early in the piece, to make absolutely sure the space elevator is strictly for the benefit of all. It must not be used for any military purpose and all payloads must be available before launch for multilateral, free-and-open inspection!
This new technology is potentially a highway into space and no single country, group, or individual should have overall rights to it. It has to be "for all mankind", as is written on that plaque on the Moon.

Another potential problem is the possible use of carbon nanotubes as horrible weapons here on Earth. I saw reference to this possibility in a fictional book some years ago and it still gives me the creeps just thinking about it!
You can make a carbon nanotube thread so thin it is virtually invisible to the naked eye but with staggering tensile strength. If you take about 2 metres of this thread, attach a handle at one end and a 500 gram weight at the other, and swing the weight round and round whilst holding the handle, you have a cutting weapon of chilling efficacy. The taut, exquisitely thin, but enormously strong thread would easily sever a human body clean through at the waist (or anywhere else) without losing any appreciable momentum at all! The cut would be so fine you wouldn't know it had happened until you tried to turn around ... !
An absolute nightmare!!

This space elevator technology is just one of a new range of applications of materials science which promise to revolutionise our civilisation over the next 20 years. I think the law makers will be scrambling to catch up with developments during that time in order to protect us all from the potential 'dark side' of these new inventions. And let's face it, somehow there's always a 'dark side', isn't there?
???

Free Spirit · 2003-09-19 01:41:13

Supposedly it could launch payloads for a $100kg. Just imagine the possibilities of amateurs designing and launching their own space probes to go to places like Venus. At those types of prices I might try to send my own doomed robot to the surface of Venus since nobody else seems willing to do it. I imagine you could piggy back your cargo on the back of somebody else's. And Shaun, thanks for that wonderful image of being cut in half with a string of carbon nanotubes. I've read a lot of articles on nanotubes but never have I come across a sick thing like that. :laugh:

Byron · 2003-09-19 04:49:00

The biggest problem, apart from the ever-present threat of attacks by ignorant religious zealots, may be the orbital debris we've left cluttering up near-Earth space. Sooner or later, I suppose we can expect an impact on the cable by a chunk of metal travelling at 27,000 km/h!! This is new territory for theoreticians, I should imagine, and samples of the cable will have to be tested in labs to see how they stand up to that sort of collision. If a cable is going to shear through when hit by something, then it may prove impossible from a safety point of view to ever utilise this brilliant new technology. And what a terrible shame that would be!

I guess what we would have to do is create a laser-based defense system for the elevator cable, so if the path of any object (including missiles launched by terrorists and other bad guys) intersects the cable itself, it would be vaporized by these automatic lasers. Anybody else have any ideas for "cable safety?"

I believe moves should be made, early in the piece, to make absolutely sure the space elevator is strictly for the benefit of all. It must not be used for any military purpose and all payloads must be available before launch for multilateral, free-and-open inspection!
This new technology is potentially a highway into space and no single country, group, or individual should have overall rights to it. It has to be "for all mankind", as is written on that plaque on the Moon.

Yes! Yes! Yes! Not only is this just plain ol' common sense, it's the only way that the doors to outer space will be opened to the human race.

You can make a carbon nanotube thread so thin it is virtually invisible to the naked eye but with staggering tensile strength. If you take about 2 metres of this thread, attach a handle at one end and a 500 gram weight at the other, and swing the weight round and round whilst holding the handle, you have a cutting weapon of chilling efficacy. The taut, exquisitely thin, but enormously strong thread would easily sever a human body clean through at the waist (or anywhere else) without losing any appreciable momentum at all! The cut would be so fine you wouldn't know it had happened until you tried to turn around ... !

You mean the "shadow square wire" in Niven's "Ringworld?" I've seen this effect in a couple of movies I do not care to see again (Yuk!), and yes, you're right, it would make a very formidiable weapon...especially in large crowds.

But overall, I'm thrilled at the prospect of space elevators, and I sincerely hope I live long enough to see one built in my lifetime...a real motivation for me to stick with my beneficial lifestyle changes!

B

Byron · 2003-09-19 04:58:02

I have a question about the use of space elevators...

Is there any sort of physical limitation to how fast the individual elevator cars can travel up and down the cable? Considering that "Zero Station" would be something like 36,000 kilometers above the ground; unless the lifts traveled at tremendous speeds, it would take days to travel this distance, just like KSR described in his "Mars" novels. Considering that elevator cabs generally don't have much room, I don't particularily relish the idea of being strapped to a chair for five days or whatever...I think 10-12 hours would be about as much I could stand, which would require a lift speed of about 3000 kph or so.

B

sethmckiness · 2003-09-21 09:12:29

Well, with a cable dropping launch costs, one would be able to launch a craft to recover space junk for an effiecient cost. Plus one would have the fuel to manuever. Making a cosmis junk yard..

Free Spirit · 2003-09-21 18:35:12

I have a question about the use of space elevators...
Is there any sort of physical limitation to how fast the individual elevator cars can travel up and down the cable? Considering that "Zero Station" would be something like 36,000 kilometers above the ground; unless the lifts traveled at tremendous speeds, it would take days to travel this distance, just like KSR described in his "Mars" novels. Considering that elevator cabs generally don't have much room, I don't particularily relish the idea of being strapped to a chair for five days or whatever...I think 10-12 hours would be about as much I could stand, which would require a lift speed of about 3000 kph or so.
B

The FAQ at ISR says it would take about a week for a climber to reach GEO. Apparently the first SE isn't being designed to carry people, but rather only cargo. That seems like a logical first step to me. You wouldn't, after all, strap people to the first rocket ever designed without it going through extensive testing.

Spider-Man · 2003-09-21 19:37:20

You can make a carbon nanotube thread so thin it is virtually invisible to the naked eye but with staggering tensile strength. If you take about 2 metres of this thread, attach a handle at one end and a 500 gram weight at the other, and swing the weight round and round whilst holding the handle, you have a cutting weapon of chilling efficacy. The taut, exquisitely thin, but enormously strong thread would easily sever a human body clean through at the waist (or anywhere else) without losing any appreciable momentum at all! The cut would be so fine you wouldn't know it had happened until you tried to turn around ... !
An absolute nightmare!!

Yes, this was explored in Cube, which was pretty dissevering.

How about using the ISS as an anchor, for carbon nanotube ribbon cables, at first, as tethers to launch payloads without rocket propulsion to escape from LEO. Why? Because the ISS is there, and we'll need to "walk before we run" with cable deployments in space....

Darnit, we don't need the ISS! heavens, it's such a useless piece of junk.
And no, that would be technologically infeasable, and certainly impractical.

alokmohan · 2003-09-23 06:22:26

Longing to ride space elevator.7 days is too long but exciting.How long it may take to have the real thing.Any idea?

alokmohan · 2003-10-19 04:19:59

Any new development on space elevator?

Shaun Barrett · 2003-10-20 02:03:17

As far as I know, the so-called 'climbers' will probably travel up the cable (or ribbon) at speeds in the hundreds of kilometres per hour. I've never heard of speeds higher than that being considered so I assume there must be some good reason why not - perhaps there is concern about wear and tear on the cable itself (?).
Geosynchronous Earth Orbit (GEO) is about 36000 kms up so, if we assume a speed of 500 kilometres per hour, the ride will take 72 hours, or three days.
But the climbers will eventually be large and well-appointed, with sleeping quarters, dining rooms, entertainment areas and observation deck(s). I imagine them as large luxurious railway cars, but elongated vertically rather than horizontally.
Far from being a boring chore, riding one of these things up to GEO will be one of the most fascinating and exciting things anyone could ever do. Apart from the simply staggering view of Earth receding below us hour by hour, there will be the novelty of experiencing gradually reducing gravity. At the outset, of course, you will be at Earth's surface and subject to the usual 1g pull we're all used to. When you arrive at GEO, you will be in freefall and effectively weightless. At various points along the way, you will experience 0.5g (Sir Arthur Clarke has suggested a hospital platform at this level, where the reduced gravity may be beneficial for convalescence from certain illnesses), 0.38g or Martian gravity (another platform here may be useful for experiments to determine the long-term effects of living on Mars), and 0.16g or the equivalent of lunar gravity.

[For those travelling on to Mars, the climber will have to be rotated as it passes beyond GEO. This is because the predominant force experienced by the passengers will, from there onwards, be centripetal force and they will feel 'gravity' pulling them upward away from Earth! The further along the cable they go, the more pronounced will be the centripetal force. At another platform, the passengers will get off, transfer to an Earth-Mars vehicle and get ready for a stomach-churning release from the cable, which will be reminiscent of the feeling you get when you jump off a diving board! In much the same way as when you twirl an object around on a string, and then let go, the Earth-Mars vehicle will fly off at a tangent (literally) for its coast to Mars.]

So I don't think anyone will really mind this amazing journey into space, especially when you consider how much cheaper it will be and how it will open things up for the ordinary person who wants to experience space travel.
Here in Australia, people get in their cars and drive for three or four days to get to vacation spots. In many ways, this is far more of an imposition than a space elevator ride, and far less of an adventure. And, eventually, statistics may show that a trip into space is actually far less hazardous than a driving vacation ... who knows?!

dicktice · 2003-10-20 07:27:58

Before tackling the Space Elevator: How about using the ISS as an anchor for carbon nanotube ribbon cables at first, as tethers to launch payloads without rocket propulsion to escape from LEO. Why not? The ISS is already up there, enabling us to "walk before we run" while learning the in's and out's of tether deployment in Earth-orbital space....

Shaun Barrett · 2003-10-21 01:00:36

I've never been comfortable with the concept of tethers because I can't see how we will ever be able to coordinate the arrival of the 'skyhook' and the vehicle to be elevated to a higher orbit, in the same place at the same time! This sounds like such an exquisite orbital ballet I don't believe it will ever be practicable.
In any event, the research and development, and gradual build-up of on-orbit experience required to master it, will delay its implementation for many years.
In the meantime, I suspect development of the space elevator will move along faster than expected and will, by virtue of its cost saving and sheer elegance, become the logical method of choice for deep-space launches.
Given the advances in nanotube production methods needed, I wouldn't be surprised if the first elevator 'ribbon' is in place by 2015. Its almost magical allure, a la 'Jack and the Beanstalk', should result in an acceleration of the technology and the deployment of more and stronger ribbons. Conceivably, there could be as many as a dozen heavy-duty elevator cables spaced out around the equator by 2030, giving unparalleled and routine access to space to people all over the world.
Maybe tethers can be made to work but, for my money, space elevators should be given priority.

Spider-Man · 2003-10-21 08:42:57

The ISS is already up there, enabling us to "walk before we run" while learning the in's and out's of tether deployment in Earth-orbital space....

Goodgod, Dick, who he heck paid you so much money to be the Space Station's cheerleader of hopelessness? Stop trying to waste my money, and that of every other taxpayer on that hideous contraption which has taken so very much away from humanity without any significant return.

dicktice · 2003-10-21 09:59:40

Well, since a "space elevator" is a tether, I can't imagine putting one up before starting with what Shaun's "ribbon by 2015" prediction suggests. (A tether by any other name, is still a tether.) And how to do this without first having an orbiting space platform in place, from which to deploy it, leaves me to wonder: With the ISS already lofted, why wait for (?) to take its place. I truly would like to discuss possible scenarios for constructing the first space elevator....

Shaun Barrett · 2003-10-24 00:51:54

Hi Dicktice!
The ISS is in the wrong orbit for a space elevator. It's way too low and it's way too highly inclined to the equator, and it's not necessary as an anchor for the first elevator anyhow.

Have you heard of HighLift Systems? They propose simply to loft a 100,000 km. long reel of carbon-nanotube ribbon into geosynchronous orbit which, as you know, is at an altitude of 36,000 km. From there, they will lower one end (weighted) to a floating platform on the equator in the eastern Pacific, while extending the other end outward (using centripetal force) to an altitude of 100,000km. Simple!
The ISS is entirely superfluous in this scenario.

For a more detailed report, see this site.

dicktice · 2003-10-25 16:26:59

Shaun: Not what I meant. Simply because it is there, use the live-in facilities of the ISS, to research and demonstrate how to deploy tethers, both up and down, manually as well as remotely. From what I've read, the few trials so far, have been botched due to mechanism and/or operating technique failures. Walk before you run / Repeat-repeat-repeat until you get it right--before attempting the all-or-nothing attempt--are my (admittedly anti-klutz) rules of field engineering! Other than that, I'm tucked right in there behind your starboard wing, flight leader!

Shaun Barrett · 2003-10-25 18:38:32

Rrrroger that, wingman!!

O.K. I'm with you now. Practice makes perfect and all that. Sounds good to me ... especially the 'anti-klutz rules of field engineering'!!
:laugh:

Alistair · 2003-11-02 12:05:50

So where would we build the Space Elevator? On land or out at sea?

I'm concerned that it would become a target for terrorism or other warfare.

I'm in favor of somewhere out in the Pacific, where only nation states could possible threaten it.

I'd imagine there would need to be an almost permanent defensive force in the area to protect it.

Utlimately I can forsee several space elevators around the world, 2x Pacific, 1x Atlantic, 1x Indian Ocean.

Land based space elevators would be feasible if people decided to pull there heads out of where the sun don't shine and not decide to kill anyone who doesn't agree with them.

My two cents.

BoBo · 2003-11-02 16:01:25

I don't know if you guys know about this company. There are some pretty interesting details on their site regarding the space elevator:

http://www.liftport.com/

dicktice · 2003-11-04 15:39:59

Nice sales pitch. Hard to believe they were able to register the name "Space Elevator" though, I'd think that by now the term would be in the public domain. I'd like to see how any of you enthusiasts would go about constructing the thing, step by step scenario-wise, to get an appreciation of the scale and timeframe of such a project. (Leaving out the suicidal terrorism aspects, for the present, as being all too daunting.)

Shaun Barrett · 2003-12-21 07:12:01

Things are shaping up nicely!
An industrial heavyweight and household name has stepped up to the plate to encourage the future of space elevators. Who am I talking about? Why, none other than that doyen of the world of elevators .. OTIS, no less!!

Already in the process of creating new and innovative elevator systems for the sky-scrapers of tomorrow, including multi-storey elevator cars, Otis says it can produce low maintenance vehicles for the space elevator in a time frame of just 10 years!
Apparently their personnel see no technical show-stoppers in the way and seem perfectly confident it can be done.

For the full story, have a look at This Site.
This could be the start of something big.

Rxke · 2003-12-21 11:53:37

i was going to reply that i thought they already announced something like that, years ago...

Shaun, that's a relatively old article you dug up... Wonder if their claims still stands, today

Shaun Barrett · 2003-12-21 21:03:33

Oops!!
How embarrassing! :laugh:

I noticed the article in a side panel at spaceref and automatically assumed it was a recent development ... didn't even check the date before posting.
Sorry folks - thought I was on to something new.

Good point, Rxke. I haven't noticed anything from Otis other than that article and I hope they're still ready and willing to put their expertise into the space elevator.
In any event, it made me feel very optimistic for a while!

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