Space Elevator Update 557
TheMadReaper writes "The 2005 edition of the Space Exploration Conference in Albuquerque, NM came to a conclusion earlier this week. A large fraction of the conference was devoted to the Space Elevator. Surprisingly, there hasn't been much news coverage of this conference, perhaps because it doesn't have Space Elevator in its name. The most interesting fact I got from the conference is that money is really starting to exist in the space elevator world mainly thanks to the work of Dr. Bradley Edwards at ISR and at Carbon Designs, Inc. The strong nanotube talk was also more promising than last year."
Money (Score:2, Funny)
I guess if enough money is pumped into this it will finally get off the ground sooner rather than later.
No, wait. We don't want it to get off the ground do we?
Would be cool to see this in our lifetimes.
Re:Money (Score:3, Interesting)
Unfortunately this is the same attitude that gave us "Star Wars" defence and other stuff that doesn't work. It should be easy to make one of these things - just build a Dyson sphere and work downwards.
Two main points are:
Geostationary orbit is a long way up.
We don't know yet if carbon nanotubes have the strength require to be able to handle their own mass over such a distance - or half it if you have
Re:Money (Score:5, Funny)
Re:Money (Score:5, Insightful)
You might find it surprising, then, to hear that I'm very excited about the possibility of a space elevator, despite being a lifelong atheist.
It's true that the space elevator relies on technology that doesn't exist yet. But that technology is rapidly advancing, and there have been extensive studies [www.isr.us] of the material properties of carbon nanotubes in the context of use in a space elevator. Of course, you'll have to wade through pages of Biblical references to get to the actual science, but that's something you'll just have to get used to if you want to read about space elevator technology.
In addition, a mass driver is simply NOT a substitute for a space elevator. Even if a practical electromagnetic mass driver could be built, each launch would require a large amount of energy that would never be recovered. The space elevator uses less energy to send each ton of matter to GEO than any other proposed system, but that's not the really cool part. You see, each ton of matter that is returned from GEO effectively recovers the energy required to send that matter up in the first place via regenerative braking.
This is also where I should mention that, energy concerns aside, the space elevator removes one of the largest risks from space flight - reentry. Mass drivers help you get into orbit, but they don't help you return from orbit at all. In a space elevator, though, you just press the "down" button. Simple as that.
Now, if you'll excuse me, I have to go do my religion homework. Oops, I meant to say science homework. I have such a hard time keeping those two subjects separate... but you can't really blame us clueless space elevator kooks for that, right?
Re:Money (Score:3, Funny)
It sounds really simple, but what if someone pushes ALL the buttons on the way down? If you're stopping every ten feet, it'll take forever.
Re:Money (Score:3, Informative)
I didn't mean to imply that I'd found some magical way around the 2nd law. What I meant was that all existing launch systems recover 0% of the energy expended to send objects into space, whereas the space elevator has the potential to recover at least some of the energy spent to send mass into space. All physical devices will have inef
Re:Money (Score:3, Insightful)
Well, the emotional impact of going God on a cutting-edge science project aside, it's a particularly apt metaphor. I'm agnostic, but I see the value of the Bible as parables, other possible values remaining undiscussed. As is the case with all of the major
Re:Money (Score:3, Informative)
The Space Elevator is in fact such a case: think about the absolute nightmare a cable cut would be. I mean, all that has to happen is a plane goes the wrong way, or a meteor happens through the wrong area, or bad weather, or lightning, or god knows what. That cable is going to be seriously heavy - half a ton per mile, maybe more, even designed to be as light as possible - and it's flexible so it won't get brittle, and it's, well, long. So it starts falling to earth, right?
So, you've got a highway coming d
Re:Money (Score:4, Interesting)
If it works, a space elevator is THE best way to get things in and out of orbit. Also, I am sure you realize it, but your bridge analogy is specious at best. Building long bridges and tall elevators are not comprable projects.
This implies that a clever milestone... (Score:3, Interesting)
Re:Money (Score:2)
More practical update... (Score:5, Funny)
Re:More practical update... (Score:5, Funny)
Our previous best accomplishment in this domain, pioneered by the great elevator engineer Willy Wonka with his ground breaking, or rather sky-light breaking, Glass Elevator, is short by several orders of magnitude. (You can also see early Space Elevator technology there, but we've not been able to replicate his claimed performance without a tether; see the report in the sequel to the Chocolate Factory book.)
I am confident once we overcome that problem that everything else should be easy.
(If you're wondering where that number came from, that's geosync orbit at 22,241 miles, times two as I'm using the elevator variant that continues on out for counterweight and flinging ability, and estimating 10 feet per "floor", so 22241 * 2 * 528 = 23,486,496.)
Melts in your space, not on your planet (Score:5, Funny)
Ground-breaking is right! Mr. Wonka's ingenious solution to base the elevator on a weave of microchocolate fibres is to be applauded. However, once the sun shone on this, the chocolate string melted and the elevator hit like a meteor.
Next time, Mr. Wonka, consider using Oompa-Loompa hair fibers. Or maybe you can beam astronauts into space with that TV ray. Who cares if they come back from their mission 1 inch high?
Re:Melts in your space, not on your planet (Score:3, Funny)
However, this is even more questionable scientifically than the already outrageous claims made in Charlie and the Chocolate Factory. If memory serves, while in space, Charlie and Mr. Wonka encounter an Alien Race bent on Mankind's destruction (The "Vermicious Knids", I think?), of which no independent corrobo
Still laughing - so 50+ years still (Score:4, Informative)
The Space Tethers [spacetethers.com] will be built far sooner and are really much better. These can toss you into space fast so you don't fry in the radiation belts, recycle the energy from payloads going down into payloads going up, and be built with materials we have today.
Getting stuck? (Score:5, Insightful)
Re:Getting stuck? (Score:5, Insightful)
new extreme sport.. (Score:5, Interesting)
Man what a rush.
Re:new extreme sport.. (Score:4, Informative)
If you're at geosynchronous orbit, you'll stay there, and you won't need the heat shield.
If you're above geosynchronous orbit, you'll get flung out into space with a delta vee somewhere between 0 and 3 km/second. Again, you won't need the heat shield.
Re:new extreme sport.. (Score:5, Informative)
For instance, a 80kg person who is 100km up the space elevator has accumulated ~80MJ of potential energy; this is a nontrivial amount of energy that will be dissipated as heat over a very short period-- the vast majority of it in a couple minutes.
I don't know the appropriate constants offhand (surface area of a person, etc) to calculate temperature under these thermal loads, but i can throw out a few numbers:
80MJ = 19 megacalories-- enough to raise the temperature of 190 kilograms of water by 100 degrees celsius.
80MJ = enough to run 450 standard home 1500W space heaters for the 2 minutes of heating.
So clearly, thermal considerations do matter for jumping from 100km.
Re:new extreme sport.. (Score:3, Interesting)
At 30000 meters, the density and pressure of the atmosphere are both about 1% of the pressure at sea level; this increases to 10% by 20000 meters. So basically, a person has a lot of altitude to accelerate (70,000 meters in virtually no atmosphe
Re:Getting stuck? (Score:2)
Re:Getting stuck? (Score:5, Interesting)
No.
At altitudes the shuttle can reach, the relative velocity between the shuttle and the elevator would be too great for a transfer.
Also, the shuttle can reach a few hundred kilometers. Not sure specifically what the limit is, but it's under a thousand kilometers. A space elevator has to go all the way up to geosynchronous orbit, which is 35786 km. You're out of reach for most of the journey.
It wouldn't be that hard (relative to the cost of the project anyway) to have an escape pod in elevator cars that have to carry humans. That could carry passangers back to earth, as they'd be in free fall for the most part.
Re:Getting stuck? (Score:4, Insightful)
You will not ride the elevator to space. Rides to space will be done by whatever the next Scaled Composites or some version of a future x-prize.
I may be inventing this number, but I seem to recall about two weeks for a trip to the top.
This is about low cost freight.
You can ride a horse across Canada faster than you can build a railroad, however, if you want to move large quantities of stuff, you're better off with the railroad. The Space Shuttle, and indeed most rocketry based solutions for freight is like trying to haul stuff across the country on your horse.
Rocketry, (and/or spaceplanes) still make sense for getting people up there, as long as there are things up there for people to do when they get there. The elevator will be too slow for people, but the benefits of economically transporting freight to space will make actual space construction and exploration possible.
Re:Getting stuck? (Score:5, Funny)
Nobody said space travel was gonna be easy.... suck it up and jump, ya pansy!
Re:Getting stuck? (Score:3, Interesting)
Re:Getting stuck? (Score:3, Funny)
Re:Getting stuck? (Score:3, Informative)
The premise about getting "stuck" on a space elevator is misguided, however - although so are the people saying you can't get rescued by a shuttle.
Re:Getting stuck? (Score:3, Informative)
More information (Score:5, Informative)
Space elevator: really a good idea? (Score:5, Funny)
Imagine going upwards for hundred sof miles while having to listen to Julio Iglesias' songs, performed by some guy on a synthesizer. NOOOOOO!
Re:Space elevator: really a good idea? (Score:2, Funny)
Talk about a nonstarter! (Score:3, Insightful)
Re:Talk about a nonstarter! (Score:2, Informative)
As for the NIMBY factor, seven tenths of the Earth's surface is covered by water...
Re:Talk about a nonstarter! (Score:5, Informative)
Re:Talk about a nonstarter! (Score:5, Interesting)
Re:Talk about a nonstarter! (Score:5, Funny)
But it would make a great seventies-style movie, sort of like "Towering Inferno". Frankly, I'm surprised that nobody has made a bad movie about a collapsing space elevator, now that we have all these computers. A space elevator would likely take several hours to fall, which is perfect for a movie.
Scene I. The Ribbon-Cutting Ceremony.
THE PRESIDENT: [Holding large pair of scissors] It is with great fanfare that I dedicate this space elevator to the United States of America, and its coalition of willing allied nations all over the world, without whom this great day might not have been possible.[Prepares to cut]
SCIENTIST: No, Mr. President! Cut the green horizontal ribbon! Not the black vertical one!
Re:NOOOO!!!! (Score:4, Funny)
Re:Talk about a nonstarter! (Score:3, Insightful)
Re:Talk about a nonstarter! (Score:3, Informative)
Re:Talk about a nonstarter! (Score:5, Informative)
>from its orbital anchor. Thousands of miles of pure splat!
That's why you don't build it as a cable. You build it as a ribbon, with lots of surface area. If the ribbon snaps, portions high up in the atmosphere will burn up upon reentry. The portions of the cable that don't burn will flutter to the ground - think tickertape parades.
What happens when lightning strikes the nanotube? (Score:2, Insightful)
Re:What happens when lightning strikes the nanotub (Score:2, Informative)
Re:What happens when lightning strikes the nanotub (Score:4, Informative)
Edwards already had discussed several issues: one, the potential site, has almost no thunderstorms. Also, depending on the type of CNTs that you use, many are very resistive, and would not be the easiest route to the ground, but the most difficult. A risk factor, however, would be water streaming down the tether making a more conductive path.
Is the space elevator a bit premature? (Score:5, Insightful)
The fact that we have not yet achieved one millionth of the task (and in fact fall several orders of magnitude for that) suggests to me that, much as I would love to see a space elevator in place, the job today belongs to materials scientists who are looking at shorter-term goals.
An eye to the future is great, but experimenting on climbers is like practicing the high jump: if you're jumping twice as high today as last year, I wouldn't start drawing any exponential curves. The ribbon is the really, really hard part, and we're currently so far away from it that research energy is better spent elsewhere for a while. 2010 is way, way too close.
Maybe with enough motivation we could get that 40,000 mm bridge by 2010, but somehow I doubt you're going to raise $10 million to build a bridge. The X-prize shot somebody into space for that kind of money.
I'm prepared to be wrong. I'm a software developer, and I've learned that as a consultant I can say, "Your project is doomed" with 95% accuracy before I've even heard your name. Being a nay-sayer is easy. But the real trick is being able to spot the 5% that will actually be profitable, and there are a lot of projects more immediately deserving of this kind of money.
Re:Is the space elevator a bit premature? (Score:5, Insightful)
Furthermore, I don't think the government or non-profit "angel" investors (i.e. Paul Allen) need to throw tons of money into research of nanomaterials simply because it's not a high-risk venture.
Even if an R&D operation fails to develop nanomaterials with the tensile strength necessary to build a space elevator- but they still manage to create something with 10% of the target strength- they shouldn't have any trouble turning a profit because there are so many other uses for such a technology. For once I can say with honesty: Good 'ol capitalism should solve this problem for us.
Re:Is the space elevator a bit premature? (Score:4, Funny)
They really should try for a 40 meter bridge first, then go for 400 decimeter, before attempting the 40,000 millimeter.
Dan East
Re:Is the space elevator a bit premature? (Score:4, Funny)
I agree with the point of the post, but where are you finding a creek that needs a 40 metre long bridge to cross it? I don't think a flowing body of water approaching 40 metres across can properly be called a creek.
How about a 4000mm bridge across a creek?
Re:Is the space elevator a bit premature? (Score:4, Informative)
Is it made out of carbon nanotubles or anything with the strength it would take for a Space Elevator?
No, so it's not in the same class structurally.
kg/lb (Score:5, Interesting)
Kilograms per pound? What is that?
Re:kg/lb (Score:4, Funny)
Re:kg/lb (Score:2)
Re:kg/lb (Score:5, Funny)
Re:kg/lb (Score:5, Funny)
Re:kg/lb (Score:3, Funny)
I can't say I've ever seen one, but I seem to recall that Sesame Street was always brought to me by one.
Call me a nay-sayer... (Score:4, Interesting)
When it comes to this whole Space Elevator business, the relevant question in my opinion is "would we WANT to make something like that?" To me, it's a novelty idea and nothing more. If people want to get serious about space travel, we need to invest more into the building of in-orbit construction yards (IMHO). Once we get the infrastructure in space to produce the vehicles, we'll find that occasional trips to the "Drydock" from Earth to supply it with raw materials will be far more practical than some 21,700+ mile long elevator reaching into the sky.
Basic economics says you're wrong... (Score:5, Informative)
Aside from which, manufacturing spacecraft is perhaps one of the most industrially complex things we do. Trying to replicate that in a place more remote, and with far more environmental challenges than, say, Antarctica, would have gargantuan capital costs dwarfing the elevator. In fact, the only way you could probably get the infrastructure up there would be an elevator or something equivalently cheap.
Re:Call me a nay-sayer... (Score:3, Insightful)
Back in the 60s, the U.S. decided it had to go to the moon. If we'd done it right, we'd have done it in stages, building up an infrastructure of reusable vehicles and permanent orbital stations. But that would have taken too long. So instead somebody designed a huge rocket that cost $100 million a pop -- and could only be used once! Which is why nobody's been back to the moon for 30 years.
Re:Call me a nay-sayer... (Score:4, Informative)
When it comes to this whole Space Elevator business, the relevant question in my opinion is "would we WANT to make something like that?" To me, it's a novelty idea and nothing more. If people want to get serious about space travel, we need to invest more into the building of in-orbit construction yards (IMHO).
The biggest obstacle to space travel is the cost of escaping the earth's gravity well. Space elevators offer a possible solution to this problem, assuming you can develop the materials to build a stable and reliable cable or ribbon. Building a huge construction platform in orbit is utterly worthless if it still costs thousands of dollars a pound to haul raw materials up to that platform, as it does today with chemical rockets. You'll have gained absolutely nothing. Space travel will still every bit as prohibitively expensive as it is right now.
In contrast, the cost of hauling materials up a space elevator involves the amortized cost of the elevator itself, plus whatever electrical energy it takes to run the mechanism that pulls the platform into orbit. Over time, the cost could drop to a few dollars per pound, making it cheaper to haul material into orbit than it is to fly it across the continental United States. That would truly open up space travel to the masses, and enable us to construct gigantic structures in orbit, plus haul up the fuel or reaction mass to move those structures anywhere in the solar system. That would include places like the asteroid belt and the Oort cloud, where there are resources we could harvest that would enable either additional construction in space, or that could be hauled back to earth and down to the surface via the space elevator for terrestrial use.
Once we get the infrastructure in space to produce the vehicles, we'll find that occasional trips to the "Drydock" from Earth to supply it with raw materials will be far more practical than some 21,700+ mile long elevator reaching into the sky.
Building an infrastructure buys you nothing if you can't supply it with raw materials. If we continue to rely upon chemical rockets for access to space, it will never become inexpensive enough to support the kind of construction and development you're advocating. It would cost trillions to build and supply a space drydock capable of building even modest craft. We've already spent close to $150 billion just constructing the International Space Scrapyard, and it doesn't even build anything - it just sits there. Supplying the tiny crew with food, air, water and fuel costs hundreds of millions a year. If you think a space elevator is impractical, that's nothing compared with trying to build anything substantial in space using chemical rockets to haul up the materials and components from the surface of the earth.
Re:Call me a nay-sayer... (Score:5, Interesting)
You pick up orbital speed, slowly, as you move up the elevator. Think about it this way. There is a geostationary point the elevator passes through, at very high altitude. Altitudes lower than this, the rigid rotation of the space elevator is below orbital speed. Altitudes above it, it is above orbital speed. This effect means the gravity changes as you ride it, and, in fact, you can use the top end of it to lauch space craft.
I've got a space elevator in my new novel (under revision). Arthur C. Clarke features on in Fountains of Paradise. Kim Stanley Robinson and Charles Sheffield also have them in novels. If you want more than novels, there are some technical nonfiction books out there, eg., The Space Elevator by Edwards and Westling.
Re:Call me a nay-sayer... (Score:3, Interesting)
Consider a bicycle wheel. The whole wheel is spinning, and every time the axle in the middle makes a full rotation, the outside edge of the tire also makes a full rotation. So a point on the outside of the tire has to move significantly faster, since it has to go a much fur
Re:Call me a nay-sayer... (Score:3, Informative)
The momentum comes from the Earth, which is slowed down by an imperceptible amount when the cable is climbed. This transfer is through the cable, which is held in tension by its rotation with the Earth ("centrifugal" force). In climbing, the cable is bowed slightly, which causes the cable to tug on the Earth.
Re:Call me a nay-sayer... (Score:3, Interesting)
If you try to use the elevator that way, each load you send up will change its orbit, and also tend to make it spin. That's why once the elevator is attached to the Earth, you want to move its center of mass just outside of geosynch orbit to add some extra tension to the cable. This makes the elevator dynamically stable, and transfers the impulses from using it to the Earth.
Re:Call me a nay-sayer... (Score:3)
indeed, I don't know much about this topic, it's the first exposure I've ever had to the subject. I had a misinformed concept of what this elevator would look like/be composed of, but a few response posts have given me a more clear understanding of what constitutes a "Space Elevator"... but cut me some slack, not everyone who wanders into Slashdot is well versed in every subject that comes along.
I was posting my initial gut response to a subject upon first hearing about
Space elevator simulator? (Score:4, Informative)
http://spaceelevator.sourceforge.net, anyone?
Re:Space elevator simulator? (Score:3, Interesting)
GPL'd source code [mit.edu]
Are you being served? (Score:2, Funny)
stationery and leather goods,
wigs and haberdashery
kitchenware and food...going up
First floor telephones,
gents ready-made suits,
shirts, socks, ties, hats,
underwear and shoes...going up
Second floor carpets,
travel goods and bedding,
material, soft furnishings,
restaurant and teas. Going down!
This is NOT for passengers (Score:2, Informative)
Re:This is NOT for passengers (Score:4, Informative)
Have they considered terrorism? (Score:5, Insightful)
And don't forget it'd be a tremendous icon of Western achievement. You'd better believe everyone in the US, or whatever country eventually builds one, would be proud as hell of it. The media would be going on and on about how it'll usher in a new age for mankind, and so on, and so forth. If terrorists could somehow take it out, wouldn't that have tremendous psychological value? Remember that they chose the World Trade Center and Pentagon to strike at us, two (or three) buildings that symbolized, to them, everything that's wrong with the US. Wouldn't a tower that reaches into the heavens (hello, Tower of Babel?) symbolize that even more?
It's quite reasonable to take terrorism into consideration when designing a structure. While I may be obsessing over the whole "living in fear" deal, its definitely something that needs to be considered.
Re:Have they considered terrorism? (Score:3, Informative)
However, I have the feeling the world will be a v
Not only terrorism, but.... (Score:2)
Such as system needs to have in place some sort of failsafe or redunancy so that such disasters, be they intended, or the result of Teamsters' laziness, do not destroy it all. A (non-Beowulf) cluster of several nano-lines? A sort of web of
Re:Have they considered terrorism? (Score:3, Informative)
Re:Have they considered terrorism? (Score:3, Insightful)
Same will happen with the space elevator. It'll be part of the design. Plus, I'll bet this will likely take place over the barren south pacific or something, and no planes will be allowed in a 100-mile radius of the actual elevator, giving F-14s plenty of time to
Re:Have they considered terrorism? (Score:3, Insightful)
The bottom line for me is, however, if you ever decide not to build something because it could be a terrorist target, that means they have won. [Really, instead of the trite crap that gets associated with that phrase.] But that's a whole other topic.
Highly defensible... (Score:3, Insightful)
Re:Have they considered terrorism? (Score:5, Insightful)
The Sailor's Rope Rule (Score:2, Interesting)
Re:The Sailor's Rope Rule (Score:3, Insightful)
as the rope get's longer it is more and more likely that a section of it is weak enough to break under the current load.
Re:The Sailor's Rope Rule (Score:3, Insightful)
Feasibility of the Space Elevator. (Score:2, Interesting)
Anywho. He spoke a couple years ago, subsequent to 3001's release on how at the time of writing, such a feat was nigh on impo
What provides the orbital speed of the cargo? (Score:2, Interesting)
Re:What provides the orbital speed of the cargo? (Score:3, Informative)
The energy comes from the rotation of the Earth. In a display of the Coriolis effect, as the cargo ascends it exerts an anti-spinward force on the cable, and vice versa. The result is that the cable is (minisculely) off vertical in an antispinward direction and is being dragged along by the Earth. The Earth slows down ever so slightly (but don't worry -- iirc you have to loft Australia to make a relevant impact). The gravitational potential energy of an orbiting object is
Chances of collision (Score:3, Insightful)
This reminds me of the asteroid/comet problem, the probability of a significant impact might be low, but it only takes one.
Re:Chances of collision (Score:3, Interesting)
The solution is two-fold. You build the ribbon wider in this region, which reduces the chances of a catastrophic hit. Second, you go ahead and track ALL such objects and give the ribbon a small wiggle to avo
Warning label you won't see (Score:5, Funny)
In emergency, USE STAIRS.
Even more apt, and more useless (Score:4, Funny)
This is a space elevator we are talking about. Might as well have the sign say "In case of emergency, use stars."
Building a ladder to heaven (Score:5, Interesting)
The first we're getting close to being able to handle. The second is just a matter of having a counterweight that balances the 22,500 miles of cable from the equator (more on that later) to the top. Without the counterweight, the ground end drags it down.
That means that we really need to build this sucker from the middle out: extend equal masses out and in (or up and down, if you prefer) from geosynchronous orbit. That's a very expensive proposition. Whether it's cheaper to ship carbon for nanotubes up or go and fetch some carbonaceous asteroids down to our orbit I'll leave as an exercise for the reader.
A poster above was concerned about the terrorist target of something like this. The one consolation in this one is that you can't build it on US or European soil: it needs to be at the equator. At least one SF author (I forget which) posited an elevator whose ground-level terminus was an upside-down Y to two islands straddling the equator some hundreds of miles apart. Not the silliest thing I've ever read, but I'm not sure it makes much sense. Tethering one end down will be tricky enough.
So it won't be Imperialist America that's building it... but that's not to say it won't have protestors. It'll cast a shadow pretty much across the entire planet. It will likely change weather patterns in the region.
It will create the most valuable real estate in the world.
It's going to end up in some place where technology and resources are accessible: Brazil, Equador, Congo, Somalia, The Maldives, Indonesia, Malaysia, or some Pacific Island are all candidates, my money is on a spot just south of Singapore -- there's enough high-tech industrial nations close enough to justify it there. Brazil is my second guess.
And who knows, maybe we'll find Saddam building WMDs up there. (obligatory Funny whoring)
Re:Building a ladder to heaven (Score:3, Insightful)
Given that you don't understand current designs, I'd really rather you shut the fuck up about things you have no clue about. It's ba
just plain stupid (Score:3, Interesting)
Re:just plain stupid (Score:4, Informative)
A couple of millimeters was the record in 2003. As of September 2004, the longest was 4 centimeters [duke.edu]. What will the record be for 2005? 2006? 2010? 2020?
Wikipedia also states the following:
http://en.wikipedia.org/wiki/Carbon_nanotube#Curr
In 2004 Alan Windle's group of scientists at the Cambridge-MIT Institute developed a way to make carbon nanotube fiber continuously at the speed of several centimetres per second just as nanotubes are produced. One thread of carbon nanotubes was more than 100 metres long. The resulting fibers are electrically conductive and as strong as ordinary textile threads.
Granted, these continuously-spun variants don't have the required strength yet, but I think it's still a little early to call all of this outright stupid.
Oribital Wobble? (Score:3, Interesting)
Re:Oribital Wobble? (Score:3, Insightful)
Alternately, you can observe that the mining industry has a much greater impact on the Earth's center of mass.
Ok I'll bite... (Score:4, Insightful)
Catastrophe. Yes Bad Things can happen. The amount of damage done is less than might be expected.
IS less? So this has been tested, has it?
I'll tell you what I'd expect. I'd expect if something went wrong and a "load" plummeted to earth from 5km up it would be pretty difficult to predict what sort of damage it would do... There's one of many possible catastrophes we'd like to hear whay you'd expect the damage to be
Terrorism. The thing is less a target than might be expected.
Again, IS less? This fact comes from where? A poll of known terrorists, or off the top of your head?
Yes, I know... people were executed for suggesting that the world wasn't flat, etc etc... but please - if you want a rational discussion on this thing pushing "facts" like these at us is hardly likely to sway any opinion.
Re:Like space elevators? You'll love... (Score:2)
Re:In a post 9/11 world... (Score:2, Informative)
Read the "Mars" series by Kim Stanley Robinson. There is a part where a space tether gets severed and wreaks havoc on the surface of Mars.
Re:Let it go. (Score:5, Informative)
It is a single point of failure. If any one of the millions of potential problems with a space cable turns out to be a show-stopper, the whole investment is lost.
It's possible to "prove" the space shuttle can't fly based on the number of parts and the failure rate in those parts. Yet it flies. It isn't like we've spent a fraction of the GNP on it. This argument comes down to "I don't think it will work because it seems complicated." It's actually much simpler than riding a bomb into space which is what astronauts currently do.
The benefits are small. The energy needed to shift a payload from the bottom to the top remains the same with or without the structure. The amount of money and energy spent on building the structure needs to be recovered in improved efficiency, and that seems unlikely.
This is just wrong. The benefits are huge! This would reduce cost to orbit by orders of magnitude. When you put material into space, you're not paying for the energy. It actually doesn't take all that much energy to put something into space. The calculation is easy. It's about 60 million Joules per kg (1/2 mv^2 with v=escape velocity). You can take a day to lift (which is 86400 seconds). That gives you about 700 J/s (which is the same as 700 Watts). It's the same energy you need to run 7 100 Watt light bulbs for 24 hours.
All of the investment is up front. There is no incremental benefit to this - the elevator does not become useful until it's complete. Any return on investment (including to governments in the form of kudos or re-election benefit) is delayed until long after completion of the project.
This objection is correct, but trivial. Edwards and Westling, the only ones who have done a realistic design study, put the cost at around $10 billion. That's less than the NASA budget for 1 year. That's much less than building a successor to the shuttle. That's factors of several less than the defunct superconducting supercolidor, and similarly less than the space station. Heck, Bill Gates could in theory build it for fun. Given the international nature of the problem, issues about security, the need for some additional bits of engineering/research, it is a government project. But not an outrageously expensive one.
Re:Practical use? (Score:3, Informative)
The material being discussed would be more like a ribbon, maybe a centimeter wide, a few molecules thick, rather than a one-dimensional wire.
Re:A post free of FUD, a dab of on-topic (Score:3, Interesting)
I saw your presentation at Norwescon this year, and I was interested and impressed. My only really negative comment is that it seemed a little too much like a presentation by a .com trying desperately to convince people that you really had a viable business model.
I was really hoping for a sober engineering discussion that talked frankly about the problems and possible solutions. I thought your climbing robot was the most interesting part of the discussion. But when the 'vision' guy took over that to ex