Space Elevators.....How Soon?

Bill White · 2004-05-04 14:37:33

Hmmm... scrap that, operational costs are not in the paper, only technical cost estimates: 6.5 Bil plusminus .5 bil... Now where did i read about it then? (Scratches head)

http://www.spaceelevator.com/docs/521Ed … dwards.pdf

Page 23.

Page 43 says construction will cost $15 billion and operating costs will be $100 per pound.

= = =

Since we don't know how much carbon nanotubes of the right size and shape will cost, this is just a guess, right?

And yes, elevator #1 helps build elevator #2 really easily.

= = =

A permanent colony on Mars BEFORE the elevator gets built seems like a darn good way to generate demand that will justify the decision to build the elevator.

Bootstrapping.

Rxke · 2004-05-04 15:07:30

Dang... i only re-read page 23...
and errr... it say 10 Bil (that's Billion, not a typo of your name, heh...), not 15, it's 15 years building time...

Anyhow... Their graph with projected advances of strenghth of nanowire is out of date, way too optimistic, i'm afraid

i forsee stalling of progress in that respect, unless some org gets behind it to actually achieve 'space-rated' cable... Big business will be content with a lot less, for day-to-day stuff like bridges, so they won't bother pouring money in further research once they have low-cost, usable nanowire that's better than steel... (am i repeating myself? yes oh yes oh yes...)

PurduesUSAFguy · 2004-05-04 23:04:49

If I remember correctly the nanotube ribbon that was being talking about by High-Lift systems only required actual nano-tubes of around 10 centimeters in length that would be budled together to create a tape, that cuts down on a big chuck of your industrial development problems.

Rxke · 2004-05-04 23:37:47

No... They already *have* 10 cm long strands (amazing isn't it...) I believe they need meter (3foot-ish) long tubes, *and* a better way to connect them (they're very slippery, so no good adhesive with 'normal' 'glue'

deagleninja · 2004-05-05 08:36:08

Bill- Judging from public support of NEO tracking and funding, I don't think the public takes asteroids as too big a threat. This would work to our advantage concerning parking an asteroid in near earth orbit. And no I'm not talking about a civilization destoyer but rather a typical earth crosser of 100-500m in diameter. Even asteroids of this small size have millions of tons of mass and could 'fuel' our SE with electricity and mass for decades at a high rate.

I believe what we are seeing now is a practicle plan for deploying a SE. It is going to take a combination of micro and macro to get the job done. No need for complicated nanomachine walking up and down the elevator, just an on-site factory producing 10cm or longer strands and a conveyor belt stlye atomic sized 'connector' to bond our CNT together. God, it almost sounds too easy, ok tell me why it is.

And highlift has been talking about doing it for 5 billion not 20. So assuming it goes over budget, these things always do, by twice as much we are still talking about 10 billion. Money can be made doing this.

Also Bill, profit need not be generated initially. Your figuring is quite sound, I'm not arguing that. But companies often generate more funding even when their current project is just breaking even.

I think the future is very bright if reuseable launch vechicles and a space elevator are competing for the market. One will drive the other to be more efficent.

GCNRevenger · 2004-05-05 09:17:59

There isn't any need to build the cable in space... the material would be sufficently light to make the initial ribbon the ground and simply drop it from GEO. Capturing and maneuvering an asteroid is a much bigger headache than you think, if it weighs millions of tons or even hundreds of thousands of tons, it'll be too heavy to move without an Orion, NSWR, or GCNR engine etc.

Unfortunatly, carbon nanotubes are something of a pain to work with. Even if you can make them uniform and relativly flawless over inch-lengths cheaply (read: less than hundreds of millions a ton), there are still some problems!

-CNTs tend to aggregate and clump together into bundles like stacks of plumbing pipe, and don't un-conglomerate easily, just like it isn't easy to separate individual sheets of carbon atoms in graphite without ruining them.

-CNTs are slippery. Try wrapping them in a polymeric binder, and they'll slip right out, just like rebar being yanked out of concrete, only much easier. Chemical modification of the CNTs by adding groups of atoms to the side (like the ridges on rebar) is a new thing thats only somewhat effective, and not on huge ones inches long.

-CNTs cannot yet be made atom-by-atom, we're still a long way from 3D atomic manipulation of that accuracy. Plus, an atomic conveyer can't move a multi-inch-long CNT.

Bill White · 2004-05-05 09:37:47

A slight tangential question.

I read somewhere that inhalation of CNT can be very dangerous and CNT might prove to be the asbestos of the 21st century.

Any truth to this worry? Even a worry might slow thing down for quite a while.

Bill White · 2004-05-05 09:42:01

deagleninja writes:

Also Bill, profit need not be generated initially. Your figuring is quite sound, I'm not arguing that. But companies often generate more funding even when their current project is just breaking even.

I do agree with this, but we are talking financing in the manner of the dot.com or dot.bomb bubble.

Lets just be clear where this money will be coming from. By selling snake oil. And to do that you need snake oil salesmen, and women.

(Named Ben, right clark?)

Some investors will get rich. Many, many more will get bilked and at the end of the day abundant Earth to LEO will exist.

But its all based on selling snake oil and getting people to invest with irrational exurberance.

deagleninja · 2004-05-05 10:53:31

Bill or GCN, how much weight are we talking about if we lift the entire cable from earth-to-orbit? I know the material is light but we are talking hundreds and hundreds of miles of the stuff.

Euler · 2004-05-05 11:21:04

I have seen 650 tons quoted as the mass of the cable.

RobS · 2004-05-05 12:26:10

I agree with GCNRevenger about the asteroid. If we need tens of billions to send humans back to the moon, I think we'd need tens of billions to move asteroids to the Earth, especially if we want to do it in less than a century. An ion engine just wouldn't have the thrust to do it in a reasonable amount of time. If you want to send people along to make sure nothing breaks, the cost will exceed the construction of the elevator. Finally, I don't see the governments allowing anyone to move asteroids to earth orbit. It's too risky. Even a fifty meter asteroid could generate a big tsunami if it impacted the Pacific (and that's almost half the earth's surface). I suspect before any asteroids are moved, there will be treaties limiting their size, and perhaps the first efforts will be to put one or two in orbit around Venus where a mistake can't hurt anyone and a success could provide a nice base for remote exploration of that world.

I doubt a space elevator will work well with people. If a car can move up the elevator at 100 miles per hour, it will take 210 hours--almost 9 days--to reach geosynchronous orbit. People will spend most of that time frying in the Van Allen radiation belts. That means any passenger car has to have lots of space, beds, a restaurant, and a lot of radiation shielding. Maybe cars could move up 200 miles, stop a few hours so the passengers could enjoy the view, then go back down. But the passengers would not be in weightlessness because they wouldn't be orbiting.

A space elevator won't get things into low earth orbit very easily, only high earth orbit. To get to low earth orbit from geosynchronous orbit requires a deorbit burn of 1.6 km/sec, then a 2.5 km/sec burn (or aerobraking) to circularize the orbit. A station about half way to geosynchronous orbit might solve that problem, though. A vehicle deployed from that point would naturally fall toward the earth, and a small burn could deflect the vehicle around the earth enough to allow aerobraking to circularize the orbit. I think.

-- RobS

deagleninja · 2004-05-05 12:48:33

Aw come on guys, quit raining on my parade

I wouldn't suggest a space elevator to geosynch orbit either, at least fo passengers. At 100 miles an hour, our cable car can reach altitudes comparable to the ISS in 2 hours, which is much more reasonable.

Speaking of a 50m asteroid, it's not as hard an engineering feat as most think. When I mention this most people assume we are going to park a massive rocket booster on the surface of an asteroid and push it into an orbit with brute force. I'm talking about capturing a NEA with a similar orbit to Earth's. it might have to loop around the Sun and Venus several times before it's ready to begin entering Earth orbit. Over years, tiny orbital changes add up to big differences.

Granted, the public might not like the idea, but it could be sold. I mean, we are talking about giving Earth a second moon, which is quite romantic I feel. But, being realistic, this probably is a project for the second elevator when nanotech is further advanced.
:bars2:

GCNRevenger · 2004-05-05 15:50:38

I'm still thinking that you vastly underestimate just how heavy an asteroid is... I mean come on, read your own posts. Millions of tons? We have enough trouble imparting 6-7m/s on a ~100 ton Mars ship, but this is completly different. Nothing we have today could make nudge against somthing that big except Orion.

And there still isn't any need for it... a 50m long asteroid is of little practical use. Thats smaller than most football fields, and this idea of dropping mined mass off it for power? Why? Just put a power plant at the base, its much more practical and less problematic.

CNTs themselves aren't all that toxic, i'm thinking you are thinking of Fullerene carbon, which might be. A little different.

Mark Friedenbach · 2004-05-05 17:54:17

I wouldn't suggest a space elevator to geosynch orbit either, at least fo passengers. At 100 miles an hour, our cable car can reach altitudes comparable to the ISS in 2 hours, which is much more reasonable.

There's not choice involved, space elevators go to geosynch and geosynch only. The center of mass has to be in geosynch orbit or the cable will just fall down to earth.

deagleninja · 2004-05-08 08:18:45

Yes, but we need not ride the cable all the way to the top.

deagleninja · 2004-05-08 08:20:48

GCNRevenger, so an ion drive working over say 10 years would have no effect on something a million tons?

ANTIcarrot. · 2004-05-08 09:10:20

A solar powered mass driver can move a 1,000,000MT asteroid into earth orbit in a couple of years; with a 50% loss of mass on the asteroid. According the the NASA studies of course.
http://www.newmars.com/forums/viewtopic … ...5;t=145

Made a slight error in the above link. STS can put ~160tons into LEO, counting the shuttle, payload, and ET - which counts as 'fuel' for the mass driver. Assuming 140 of this is usable payload we need 72 HHLV to put NASA's 10,000ton rock-tug into orbit. (3000ton tug + 7000 ton reactionmass) Assuming they cost as much as the shuttle to launch (not unreasonable IIRC) cost would equal $43B. Assuming a cost of $20M/ton, the tug part of that mass would cost ~$60B. Double this for government stupidity and you have a final tally of $200B to place a half million ton asteroid in orbit.

This is the 80s eco way. There are nuclear options, but they are not required for shoving asteroids around, and at least someone semi-qualified has done the math on this one.

Alternatively, launching the cable from earth the boring way (via protons perhaps?) would cost ~ $3.4B - plus manufacturing & misc costs.

And at 1G, 36,000km can be covered in little under 45 minutes, though half of that would require passengers to sit down for the 2G upwards portion.

ANTIcarrot.

Mark Friedenbach · 2004-05-08 13:59:47

Yes, but we need not ride the cable all the way to the top.

You could stop at LEO, but it'd be pretty useless -- you'd fall right back down to earth. You'd still need a horizontal delta-v of 7.35 km/s, which is huge. You might as well continue up to the top.

drudgeman · 2004-05-14 15:32:15

ISR (http://www.isr.us]www.isr.us) seems to have the lead on space elevator research. I understand that the “father” of modern SE research Dr. B Edwards, has a huge research staff, government funds and real scientists working on it.

The other company I found Liftport (http://www.liftport.com]www.liftport.com) seems to be some kind of scam site for investor cash. Come On!! Lego lifters? Liftport Carbon? Finance and media? ALL run from the same office suite. And they have 3 employees? NONE with any degree, that we can see, in anything let alone the science needed to build it. Mike Lane?? Never heard of him but a Nexus-Lexus search shows that he almost lost “Liftport HQ” to the bank more than once, was almost sued by the city for fraud (settled out of court by purchasing the building out right to stop a law suit) and on some news sites he is “Dr. Michael Lane” but there is no degree that we can find- ANYWHERE.

And his relationship to Dr. Edwards?? I called and asked Dr. Edwards. Liftport and Highlift NEVER received any “NASA Grants," Dr. Edwards did, personally and through a company called Eureka Scientific.
I think the SE is a great idea but fear unscrupulous companies could kill it.http://www.isr.us]My Webpage

TrevorM · 2004-05-16 19:41:12

GCNRevenger, what's all this talk about an asteroid? The space elevator doesn't use an asteroid as a counter-weight.

Bill, I think you are underestimating the uses of a space elevator. For example it can be used to develop the Moon, and I mean really develop the Moon. You just start hauling equipment to the top of the ribbon and let go at the right time to get flung towards the Moon (Or Mars for that matter).

If you put a hotel at the top of the space elevator it would get "gravity". As you ascend the ribbon gravity will get less and less until you get to GEO (35,786 km) when it reaches about zero and the centripetal force balances out with the pull from Earth (which is why GEO satellites don't fall back to Earth or go flying off into space). Now since the space elevator goes beyond GEO the centripetal force will start to overpower the gravity pull from the Earth increasing the higher you go up the ribbon. I can't remember at which height you would get gravity of 1g, it may be twice GEO but I'm not sure.

Oh, and personally I would like to enter the Earth atmosphere at a nice leisurely speed of 200km/h and not blasting in at 24,000km/h

-TrevorM

Bill White · 2004-05-16 19:53:46

Bill, I think you are underestimating the uses of a space elevator. For example it can be used to develop the Moon, and I mean really develop the Moon. You just start hauling equipment to the top of the ribbon and let go at the right time to get flung towards the Moon (Or Mars for that matter).

There are plenty of good payloads for a space elevator if it is economical. But please review the basic math.

Take the total cost to deploy at multiply by 10%;
Take that number and divide by 365;
You need to generate that much revenue per day just to cover the interest.

How many climbers are needed to do that? How do all these climbers arrive at the elevator base? The cost of the bare-bones elevator is just the beginning of your infrastructure.

Do we count the cost of shipping from Los Angeles to the elevator platform off the coast of Ecuador?

= = =

In any event, an elevator only makes sense =IF= there exists substantial demand. More chickens and eggs. Build low cost Earth to LEO and hope people use it or go out there are create demand and let the private sector fill that demand?

TrevorM · 2004-05-16 20:24:03

Take the total cost to deploy at multiply by 10%

Multiply it by 10%? Wow... maybe you meant add 10%, or multiply by 10? I'm guessing the latter.

Bill White · 2004-05-16 20:30:38

Take the total cost to deploy at multiply by 10%
Multiply it by 10%? Wow... maybe you meant add 10%, or multiply by 10? I'm guessing the latter.

Whatever. . .

10% was a decent interest rate compared to venture capital rates.

If the space elevator costs $10 billion, you need to earn $1 billion per year to offset capital costs. What is the likely life expectancy of an elevator before a ribbon needs to be retired?

Then you could do a proper amortization of capital costs.

= = =

Key point - unless you use the thing a heck of a lot, cost per pound will be much higher than is usually thought. You gotta run the thing like its O'Hare Airport, keep them cars moving up.

And feed and house the people who are going up the day after tomorrow.

TrevorM · 2004-05-16 21:00:41

Why not have the US goverment pay for it? It's pretty cheap by their standards.

If companies want to create their own space elevator they could use the public one to launch the initial ribbon (reducing the costs)

The value of the space elevator isn't just money made by lifting stuff up. It's how much is saved by using the space elevator rather then rockets.

GCNRevenger · 2004-05-16 21:12:31

If you had read previous posts, you would have learned that I didn't want to move any asteroids, and know full well that an elevator doesn't need any.

The trouble with sending people up and down is the huge dose of radiation you'd get traveling for days through the Van Allen belts (Apollo only spent an hour each way) requiring heavy-duty shielding, and that the whole elevator is fairly limited in how often it can move stuff up and down. A trip to the end of the cable at double the height of GEO would take more than a week.

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Re: Space Elevators.....How Soon?

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Re: Space Elevators.....How Soon?

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Re: Space Elevators.....How Soon?

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