Space elevator - breaktroughs predicted

Rxke · 2004-02-28 12:02:45

http://www.cbc.ca/news/background/space … r.html]CBC

Nothing really new here, for the people that know about the concept, still a good read...
Long story short: now launch costs are about 1000-10000$/kg, with the 'cable they would be in the order of 100$/kg, opening up a whole new way of doing things in space..

The big heads up is the NIAC's Phase 2 report that says scientists predict they'll get strong enough nanofilaments *within two (2) years!* [http://www.niac.usra.edu/files/studies/ … dwards.pdf](2.7Mb .pdf file)

Keep your fingers crossed...

flashgordon · 2004-02-28 14:21:18

i'm still waiting for the big zubrin news at spacedaily!

flashgordon · 2004-02-28 14:39:17

the article said the space elevator can be up and running two years after they figure out how to make 650 tons of nanotube cable at the required strength; i recently read somewhere a lot of tons of nanotubes have been made recently; i forget how much and of what quality, but I've also been reading various researchers around the world have 'solved' the nanotube purity problem. I'm sorry, but there are so many articles and i've read so many of them, that i never bothered to keep track of them all!

Rxke · 2004-03-08 00:14:45

Flashgordon...

Been doing some reading again...

Yes, production is getting a boost... 5 years ago nanotubes cost about 100$/gram, now its the same cost per kilogram, that's 1000x cheaper!
So what? Well, the stuff is still not good enough, but at that price it becomes possible to do some extensive testing of new bonding/interfacing techniques...
Predictions for usable material: mid 2004, so any moment now...
Of course, once the "Right Stuff" is on the market, there's still a long way to go. Biggest stumbling-bloc is... funding.
The detailed cost-estimates for a cable are 20 Billion in the worst-case-scenario! 6Billion is seen as more realistic estimate, BTW... That's peanuts, considering a working cable could earn approx 6Bill a year in the first year, more in the following...
But... The long lead-time before operations (10-15) years makes investors weary... They're used to immediate return of their money, not a 10-15 yrs wait...

Rxke · 2004-03-08 00:39:33

Now... Mars.

Considering a 100$/kg (50/poud, roughly) launch-cost, we're having a whole new playground...

I didn't find the reference, but there's some between-the-lines talk in certain papers (Also in the NIAC report) of Zubrin working together with the 'cable-guys' to write a whole new Mars-Direct plan, using the cable... Of course it won't be really 'direct' anymore, but I'd be really interested in what he has to say...

Once there's a cable on earth, deploying one for Mars is kind of straighforward, it's a lot easier than to do it for the moon(!) So the second cable is almost a sure thing to happen on Mars, not on the Moon, Yihaa!

Furthermore... For the asteroid-miners... That's even *simpler.* Turns out there's even no need for nano-whiz-bang stuff, we could do it today, using Kevlar, but current high launch-costs make this impractical... So, again, waiting for the cable on Earth, and we could see a new space-market develop fairly quickly.
Another market that'd be feasible is solar farms in Eart orbit, BP is interested, and doing research...

So, who's going to kickstart this thing, government or private enterprize? Well that's the bad news: private investors are interested in operating the thing (of course) but not funding the actual building. Government needs to vote a big sum, kinda unlikely, US has other priorities (the Moon, bleh) Europe, Russia, Japan, China? Hmmm...
For the moment, Canada seems most interested of all, but won't go as far as footing the bill.

So again waiting for the bean-counters to get their act together... Once the realize they'll be the sole provider of the entire space industry, (10x cheaper than the rest...) it's going to happen, but it looks like such a far-out concept, you need some imagination to 'buy it' of course

Rxke · 2004-03-08 01:13:02

About the cable strength... A letter from 2/2004 (From the Yahoo!list, potsted by Keith)

I asked Dr. Edwards about all this, and this is what he said (I assume everyone would consider him to be "in the know", whether they agree with his predictions or not):

Keith,

I have a reference I can get you for CNTs with measured strength of 150 GPa.
These are microscopic samples. As for ropes... that is not the way to go anyway. The University of Kentucky and others are now making CNT composite fibers of kilometer lengths and strengths as high as a few GPa's.
We will have fibers of this length >10GPa before 2005. We will be shooting for much higher in 2005. This is the state of the art.

Brad

So predictions were a bit optimistically. They need 100GPa for a cable...

Shaun Barrett · 2004-03-08 02:16:32

Thanks, Rxke!
I'm a rabid space elevator fan ... can't wait for it! :bars2:

This new information is most encouraging and it looks like we're definitely on track for the first cable by 2015.
As for investors, I think we need a major publicity campaign to bring the concept into the limelight. Many patient investors put their money into tree farms (timber) and don't expect a big return for many years. Perhaps those investors, if they understood the advantages of space elevator economics, would be happy to buy shares(?).
There are millions of shareholders all over the world. How many would it take and how much would they have to invest to raise the 6 or 10 billion dollars needed?
???

Rxke · 2004-03-08 03:42:14

Some big investors are on the fence, I think. For example BP Solar, wich reviewed the plans and were very impressed, saying the plans were definitely out of the 'just a bunch of guys with a plan' phase, and already well into engineering phase.

BP Solar is interested in building solar-farms, wich is a long-term investment already, so maybe...
Canada is actively supporting the plan, they're even funding the building of research stations, and promise some kind of plan for investors to give them some kind of recoup, forgot the details, but definitely more than cheap words...
Looks like Toyota, too is interested (huh? :laugh: ) together with some Japanese Heavy-industry giants, there'll be a substantial market for the sea-going 'anchor' vessels, drydocks, supply etc...
It is a potentially *huge* market, not only the space-industry itself, but also a lot of support-tasks, so a broad spectrum of the industry is taking notice.
Edwards, the guy behind the NIAC report keeps repeating how positive the reactions are... Both from the industries and from the press...
Guess it is now waiting for the first big investor to take the jump...

(Edit) 'Bout the shares/bonds and all that... They chose not to issue those, yet, because they thought it would make them look 'vapourware' sellers, AND they were not sure it would be legal(!) There are still some legal technicalities to be ironed out with different organisations, though it looks good (as long as none of the "classical" launch big guys starts to work behind the scenes to try and make things difficult, i can imagine Boeing, etc are none too thrilled with the cable...)

Shaun Barrett · 2004-03-09 01:14:57

Excellent!
Sounds like the whole process is further along the development path than I thought. And, when you consider that the cost of putting up the first space elevator is about the same as the amount of money American kids will spend between now and 2015 on chewing gum (! ), I'm very confident this dream will soon become reality.

In the great scheme of things, $6 billion isn't really a lot of money to pay for a 'railway' to Low Earth Orbit.
And when it comes to solar system travel, LEO is half-way to just about anywhere. The biggest impediment to our large-scale exploration and exploitation of the planets and asteroids will have been removed, opening up an almost limitless future for humanity.

I just love it!!! :up:

Rxke · 2004-03-09 12:30:03

It isn't just for LEO... It's supposed to be for *any* Earth orbit, so also GEO, interplanetary etc...

By using (largely untested, admittedly, but at that price experiments will surely be done...) tethers and teeny-weeny upper stages...

You know, IMO the nice thing about this cable is, research promises tremendeous spin-off profits, not only for the space industry... Try to imagine the market for super-strong wire, it's awesome, from bridges to clothing...
That alone will keep researsh going forward, it's not like you're building a new kind of rocket, with a limited market-potential, not at all...

DannyITR · 2004-03-13 00:25:26

I was also not aware of the amount of progress. Until reading this thread, I thought space elevators required a 50km high building or something (I believe there was a thread on this forum about it or perhpas slashdot) which is utterly ridiculous and stupid since 50km is almost in space.

Once they get the materials, they say 2 years, so why the wait until 2015? I'd think it would be more like 2010.

interstellarvoyager · 2004-03-13 15:51:53

My first (& maybe last) post...

The Space Elevator - always excited by this idea since I read the AC Clarke novel siting this huge tower on a (South-shifted to the Equator) Celon (OK, Sri Lanka - which apparently translates as Royal Celon...)

Eyeballing the Space Elevator website a while back I recall that the tower is no longer required - you "just" lower a cable (yea - ribbon) to an equatorial sea platform from a satellite hovering in synchronous 24hr orbit - piece of cake, really. The ballancing force is supplied by "letting out" a countermass into higher orbit.

You can drop into any orbit from a given height up the cable - although any but synchronous will require thrust if the orbit's to be circular. One of the beauties is that by climbing up high near the countermass you can in theory get thrown out to Mars and beyond. (This must what Doc Z is working on... )

I have a feeling that this will all happen, the only snag is we'll lose those spectacular rocket liftoffs forever. (Ahh, that majestic Saturn V) :;):

Rxke · 2004-03-14 04:14:26

I have a feeling that this will all happen, the only snag is we'll lose those spectacular rocket liftoffs forever. (Ahh, that majestic Saturn V) :;):

Heehee, yup, no longer wil our heroic astronauts fearlessly ride a flames-spewing, bones-crushing dragon... They will take the elevator, just like us mere mortals do

GraemeSkinner · 2004-03-15 09:57:13

Heehee, yup, no longer wil our heroic astronauts fearlessly ride a flames-spewing, bones-crushing dragon... They will take the elevator, just like us mere mortals do

The big question however is what sort of music will they have playing in the elevator, its not going to be a short journey after all! Can you imagine a few miles of the usual lift music?

Rxke · 2004-03-15 12:48:19

You can always use that N'Sync guy as a errr... testcase, he's supposed to be used to that kind of (CENSORED)

Or imagine Aerosmith's "Love in an elevator..." :band:

10,000,000 times, gawd make it stop, please!

SBird · 2004-03-15 15:50:25

I hate to be the wet towel here but those 2 year estimates for attaining the required cable strengths are wildly optimistic. In the next 2-10 years, we will see practical carbon nanotube fibers become a reality and start hitting specialized markets. These fibers will have several times the strength of present high tensile strength materials like Kevlar and will revolutionize engineering.

HOWEVER, I'm highly dubious about these 1st gen fibers being good enough for a space elevator. IIRC, the theoretical strength of CNTs is something like 300 GPa and the strength needed for a apace elevator is something like 100 GPa. Presently, we're just starting to push past 1GPa to 10 GPa with existing CNT cables. The major problem is that the actual CNT's are only a few microns long and are held together by glue. Therefore the bulk strength if the cable is largely determined by the glue strength and the strength of the glue-CNT bond which is weak since the graphene structure of CNT's is quite slippery.

There are proposals to chemically modify the CNT's so that they bond to the glue better and this will lead to a significant increase in the cable strength. However, the glue still will remain a weak link. Furthermore, the CNT's themselves will lose a LOT of strength due to the chemicla modifications done to them. Threfore it is unlikely that composite nanotubes are capable of the kind of strength needed.

What will ultimately be the elevator material is a cable made of single-wall, defect-free CNTs that basically run the length of the cable. Unfortunately, we have no idea how this might be done, much less used to makea 36,000+ km cable. It *might* be possible at some point in the future to do this but probably on a time frame much longer than 10 years.

DannyITR · 2004-03-17 23:50:48

We seriously need the space elevator. I think the shuttle sould be decommisioned and the ISS put on hold but not abandoned. I'm not sure if most politicians realize the benefits of such a device. The access to space would be like nothing we've ever seen and so would the economic benefits. The elevator would be a money making machine since all other countries would want in. Homefully with the 5 tonnes/day capacity (hope I got that right) we'd be able to meet demand.

My question is why hasn't this become the central part of NASA's new space policy? With the proper funding we could be building it by 2010 probably. All spaceships build to be launched from the elevator would be cheap and efficient and we could finish ISS, keep hubble, build a moon colony AND send humans to mars for a fraction of what is would cost today. Why aren't we jumping on this?

SBird · 2004-03-18 03:26:22

Well, by that criterion, we also need antigravity generators. It may simply not be possible to construct a space elevator with practical materials. Spending NASA's budget on a space tech that has a low probability of success in the near future is a bad move. NASA is in the business of getting stuff to space - they should concentrate on launch technologies that are known to work.

Carbon nanotube work is already well funded and moving along about as well as can be expected. There will be little gained by pouring money into space elevator research at this point in time. When basic nanotube research matures to the point where making a space elevator cable is practical, then NASA should get into the picture.

I've worked with nanotubes and have been closely following the field and a space elevator in 2010 is nothing but a pipe dream. If things go spectacularly well, perhaps 2020 but much likely much further out.

Shaun Barrett · 2004-03-18 19:47:50

SBird:-

If things go spectacularly well, perhaps 2020 ...

It seems to me that research and development is not always an orderly progression. Although it's a hackneyed and hence devalued term, the word 'breakthrough' is nevertheless sometimes an appropriate description of the fits and starts which occur at the 'cutting edge' of technology (Oops! Accidentally dropped another cliche ... a bit careless .. sorry! )
I visualise a new technique being hit upon, probably by accident and possibly having its genesis in a different field entirely, which will allow the 'continuous' production of unbroken CNTs of any length required - a little like the production of a nylon filament from the interface of two liquids or the extrusion of long seamless aluminium articles.

You see, unlike you, SBird, I'm not burdened by any practical experience of the difficulties involved in CNT production, so I'm able to dismiss potential stumbling blocks and cruise forward unhindered in my idealised world!

As has been pointed out, the potential uses and commercial possibilities of a CNT fibre are many, so the incentive is there. Dozens of research establishments are working on the problem, so there's an undeniable element of competition and no shortage of talent involved.
You may be right that the difficulties will prove insurmountable for decades but I don't believe you. History shows us over and over again that predictions of future technology are more often overly pessimistic than the other way.

SBird · 2004-03-18 20:53:26

Well in that case, where's my freakin' flying car!?
I look at our war on cancer, AIDS, hunger, attempt to build an economical SST, LEO booster and I see a LOT of proposed engineering projects that never panned out. It's easy to get lulled by Moore's law in semiconductors to think the same will apply to other fields. However, Moore's law only works when you havea clearly defined engineering path to follow - in this case progresively shorter lithography wavelengths.

With CNT's, the formation mechanism is sort of understood and it doesn't look good, I'm afraid. The problem is that youre trying to build flawless polymers. The probability of a polymer getting longer without a flaw decreases exponentially with length. Basically, if anything happens to the iron catalyst such as impurities or temperature changes or mechanical disturbances, the tube is killed. The problem is that all of the nanotube synthesis schemes rely upon relatively high temperature synthesis where everything is kinetic in nature. If we could find a way to get enzymes or simple organic precursors to make nanotubes, we'd be in business since then we could do things like error correcting, etc. However, it's just not possible at the 200+C that anyone does the synthesis at.

Now, if someone were able to figure out a way to join nanotubes at the ends, we might just be able to do this. It would require a supply of nanotubes of all the same diameter and chirality. It mightbe possible to do this but the costs would be stupid staggering. I mean just stupid.

The big problem is that the elevator cable is so damn long and has to be so perfect. One or the other is possibly feasible but both at the same time is really difficult. The problem is that most other engineering projects can do just fine with the low quality tubes and so the massive effort to improve the CNTs has little economic incentive other than the elevator. If the elevator requirements were just half as high as they are, I'd say that it's feasible. However, the 100 GPa just requires such perfect material that I'm not terribly hopeful.

I can't rule out some major breakthrough busting the doors open but it would require a minor miracle in present day synthesis or a completely new synthesis method.

Rxke · 2004-03-18 23:45:10

that's a very real concern. Once the industry succeeds in producing cheap 10-20 GPa tubes with a sufficient lenght, research will grind to a halt. For real-world applications that's plenty, why invest money in stronger stuff?

Shaun Barrett · 2004-03-19 00:09:20

Only time will tell.

SBird · 2004-03-19 00:33:39

I'm afraid that I agree. The glue composite nanotubes with crosslinking wil lprobably be able to hit 10-20 GPa of strength without too much trouble. That's still 20-60 times the tensile strength per pound of steel. At the very least, we can make some awesome rotational momentum transfer tethers with the stuff and greatly reduce the weight of launch vehicles.

I once saw an estimate that if we could build an SSTO made of nanotubes and diamond, it could easily carry more than it's own weight in cargo to LEO! In some ways, that's even better than an elevator. Synthetic diamonds are starting to ramp up in production. It's now possible to grow synthetic diamonds 20% harder than natural ones at 0.2 carats/hour. The process could easily be ramped up to start growing truly huge diamonds if one is patient enough. The overall cost is suprisingly low - I wouldn't be suprised if we can get the cost of the synthetic diamond to within an order of magnitude of more traditional composite materials in a few decades.

The other possibility is that someone clever will figure out a way to achieve the space elevator with a weaker material. The lower strength nanotube would then suffice.

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