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Thoughts on the Space Elevator
Keith Curtis writes to tell us that Glenn Reynolds, of Instapundit fame, has posted his thoughts on why NASA should be building a space elevator instead or their current plans. Keith has also posted his throughts from an engineer's perspective (although admittadly still not a rocket scientist). "The challenges are many, but it has been a viable option since carbon nanotubes, structures so strong that one the width of a human hair could lift a car, were invented. A space elevator could be between 10 and 2000 times cheaper than conventional technology and will force NASA to change just about everything they do. Hopefully one day that bureaucracy will wake up and realize it."
Yeah but who wants to listen to that god awful music?
...sure, if he hadn't been reading Robinson novels the night before...
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If magic pixie dust were invented it would be such a waste to spend all this money on conventional boosters. Come on NASA! Drop what's known to work and concentrate on the pixie dust formula.
But, I don't remember ever hearing that we actually have the technology to produce enough carbon nanotube material to actually build a prototype device of some sort let alone a cable spanning to LEO. I realize it's 14 years away.. but there's no guarentee we will actually have the capacity by that time. As far as I'm concerned we're better off building what can actually be finished come 2020 let alone tested and on our way to the moon.. again..
I wonder how long it will take for one of these elevators to reach their destination. If the elevators are going to take a long time they need to be big enough to hold some food and other supplies. I'm sure they will be big enough to send up large equipment though...
Sigh. Ya know, we could build a structure to space with todays (hell, 20+ year old) technology if we wanted. The Launch Loop concept was published 20 years ago and is viable today. It costs less than a space elevator is predicted to cost and, unlike the space elevator, can be built from the ground up instead of from orbit down. So yeah, please stop saying stuff like: once we have strong carbon nanotube fibres we'll have a space elevator two weeks later. It doesn't work like that. The majority of studies that remain to be done to make the Launch Loop a reality are much the same as the many studies that still need to be done to make the space elevator a reality. Someone has got to finance those studies and unless you can get PhD students to do it on government funding that means you've got to pour money into a hole that might never fill up.
How we know is more important than what we know.
this is where private ventures come in. let them take the risks and develope the tech. i'm dubious about space evelvators, but hell it's at least possible in theory if you can find materials that will last
If you mod me down, I will become more powerful than you can imagine....
A space elevator will be made of carbon fiber nanotubes correct?? What would be the effect on a hurricane hitting the elevator? Can the string be realed in from one end?? Would it be more prudent to build this in a place far away from a coastline??
Gorkman
Why isn't this stuff being used as an emergency rescue material, to make ladders that can be telescoped up to the 30th floor of skyscrapers? Surely there could be less ambitious projects for this material before committing to something that has to deal with the extreme stresses and temperatures in space and the upper atmosphere?
Make a model of a space ladder/elevator, by designing something that can save lives here at home, and it will take off like a rocket in the public's eye, pardon the pun.
Saskboy's blog is good. 9 out of 10 dentists agree.
By the same logic, my computer should be running off of a fuel cell right now, cars should be driving them selves, and world hunger should be solved. I mean really pleople, we have the technology, right?
Never eat more than you can lift -- Miss Piggy
We're nowhere near ready to start manufacturing tubes suitable for use in an elevator cable. (Maybe you've noticed their lack of use elsewhere.)
Sheesh, evil *and* a jerk. -- Jade
I like the idea of the space elevator . . . but won't it be a prime target for terrorist attacks? I mean, if I was a terrorist, it'd be the first place I'd direct my hijacked pla . . . moment, there's a knock at my door.
Oh yeah, let's spend our money on a space elevator. The world's longest carbon nanotubes are what, half a centimeter in length right now? That means only 62,000 miles - .5 cm to go!
The August issue of IEEE Spectrum also had a story about the space elevator. This article is available online here. Not knowing much about the space elevator, I found this article very informative.
People keep saying if it fell it would burn up, but it would seem to me that something strong enough to support all the weight needed would be strong enough to withstand any heat generated by falling.
Considering that it wouldn't betravelling that fast, I don't see how it could generate a lot of heat. Compared to say a shuttle reentry.
Wouldn't we also need to build it from space down?
All this is mute until we can make nano tubes as easily and reliable as we make rope.
The Kruger Dunning explains most post on
I can understand the occasional typo slipping through, but three? Come on; dupe or don't proofread, but don't do both.
English is easier said than done.
...will partner with NASA to make great strides in space elevator music.
--I'm so big, my sig has its own sig.
-- See?
The guy actually spelled "nuclear" "nucular". Yikes. I hope that was a subtle joke.
It's going to be one hell of a long ride and I'd hate to overdose on strings.
Abstinence is a government conspiracy. www.SafeSexZone.co
In his dreams, he's Ariel Sharon's man-wife.
If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
If you can invest a few billion and get much cheap access, then doing anything else is obviously irrational.
OTOH, I seriouly doubt the ability of the US goverment to do anything cheaply. That is the real problem.
Rocket powered spaceflight should be much cheaper than it is today as well, and that sorry fact is what makes the SE look so attactive.
First of all, the ribbon idea won't work, it will get curled up since it will stretch unevenly and wind and dirt will do the rest. The only practical shape for a rope is a round one. Secondly, building a climber with motors and lasers and crap is totally ridiculous, unbalanced and inefficient. Put a friggen pully at the counterweight, with solar panels and an electric motor and another damn pully at the bottom with another motor, then run two cars up and down. Then the system is balanced. Yes, the two cars will probably bang against each other when passing - so slow down when halfway and shape them to handle it so they won't get stuck even if the ropes are twisted. KISS.
Oh well, what the hell...
Ever since I read the last chapter of The Science of the Discworld I've been interested in Space Elevators and have watched /. for stories about them. I think the main reason people seem wary of really going for the idea (apart from the large technological research that would be required to make it work) is a feeling of "This is a little too sci-fi for real life", which is understandable considering Arthur C Clark wrote about space elevators in his novels decades ago.
But this is a real concept that could make space exploration and travel a very accessible, and perhaps most importantly cheaper. Instead of spending gazzillions of dollars on blasting ships off our planet laden with expensive fuel we can launch them from a "platform" above the atmosphere where the energy required to escape the Earth's orbit is a fraction of that required to do it from the planet's surface, where we must first escape the strong gravity within the atmosphere.
Apologies if I've rambled, I just think this is where NASA should be going.
"it has been a viable option since carbon nanotubes, structures so strong that one the width of a human hair could lift a car"
Yeah, but how much does a carbon nanotube cost in comparison to a car mechanic with lift down at your local jiffy lube?
Thought so. Thanks for playing. Time to go back to the server room.
I know we have to plan for the future and all, but since Mars travel probably won't be viable or even valuable for another 60 to 80 years (by which time I'll probably be dead) I would much rather have a nice reduction in taxes.
... but I really think the people should be allowed to choose which optional programs get their money - if it really needs to be taken from them in the first place.
How about this - reduce our taxes a bit, and for the non-critical portion of our taxes let us choose what program they go toward funding. Some people might choose a government funded AIDS cure - some might choose Mars exploration
However, what needs to happen first, is for us to our technology to the point where we have a high-yield, low-failure rate method of producing carbon nanotubes. It's not there yet, and I don't think it will be here for a number of years. This is not to say that there aren't good minds working on it, because there are - the University of Utah, where I study, has a team of some of the best physicists and engineers devoted to the study and fabrication of carbon nanostructures. Also there is the consideration of money. Research projects can be expensive, especially for something as groundbreaking as efficient fabrication of carbon nanotubes. It is entirely plausible that the money being funneled to carbon nanostructure research projects adds up to as much, if not more, than NASA is spending on conventional spaceflight. All this said, I think he's closer to right than wrong - space elevators would be a *massively* better way to get stuff out of the gravity well than throwing like ten metric arseloads of rocket fuel at the problem.
Time is an illusion, lunchtime doubly so. --Ford Prefect
Maybe i am a bit out of touch (although i doubt it, being physicist and seeing people who actively work in the nanoparticle research and astrophysics department everyday), but i think this is all such a bullshit.
Space elevator this, space elevator that. Its just a pie-in-the-sky dream, and will be for the next century(ies). We dont have bucktubes "thick as a hair but strong enough to lift a car".
We dont even have them a meter long and strong enough to lift an apple.
And even than, it took millenia to get from iron->steel->a few km steel wire for bridges/ect.
Singularity this or that, you shouldnt expect something like the support of the golden gate bridge via nanotube based cables the next decade(s)
(not even mentioning the hurdles of a structure 30.000km+ long and sturdy enough to support the lifting vehicle and atmospheric conditions).
Also, the best we ever did concerning long wires and space was a test a few years ago, where they even failed to unwind a 300km, unstained wire in free space.
Not to mention that to get the whole framework running you need an efficent way of getting material and people up there to begin with... without a shuttle mk2 or 3 or 4 or 5 there is not even a point to start the whole shit.
But it seems nowaydays you only need to throw some buzzwords like "nanotubes" into the crowed and they would believe you even if you promised them portable teleporters...
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
That's even better, because this is an engineering project, not rocketry.
The first thing that I thought of when I first heard about this is what a great terrorist target it would make. You could shoot at it for many miles around, which might not affect it much if it's as strong as it sounds like the material is, but one would be able to see when it was in use. It's unrealistic to think that people around the world would constantly be taking impudent potshots at anything with any accuracy, but still, it remains a very visible target, and one that would be very difficult to replace.
On a different note, I see that this would be a social and cultural catalyst. What if we build this elevator in the US, and China wants to use it? It would seem wasteful to demand that China build their own space elevator to do exactly the same. Either we would allow other nations to use the elevator as well, thereby showing at least superficial unity, or we say that we have the world's only space elevator, and if China wants one, they must build their own, which would almost certainly dampen relations.
I won't speculate on what will happen, but I think either eventual harmony or inevitable conflict would be accelerated by something of this magnitude.
..all they money from lost hours of Slashdoters reading the constant barrage of space elevator "news" went towards building the damn thing. Hell, if we included lost time/$$$ due to dupes we could throw in a Mars colony while we're at it.
This is a Big Risk If Disaster Happens project, both during construction and after completion. I know *I* don't want to be nearby if something major goes wrong. Do you?
Let's build some prototypes in space first, then on the moon or other reasonably massive body.
When we've built enough that we are sure the kinks are mostly worked out, THEN build them from earth to the sky.
I'm optimistic that an earth-based elevator can be done safely within 10 years of proving one on a heavy-mass celestial body.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
No, it hasn't.
The space elevator will become viable when someone creates a strand of carbon nanotube and lifts a car with it.
If you want to make me believe that a carbon nanotube space elevator is a viable proposition, demostrate that you can build a carbon nanotube suspension bridge first.
Doesn't have to be a replacement for the Brooklyn Bridge or the Golden Gate. A footpath over a creek at your local engineering college will do.
Until then, you're as likely to go into orbit on a space elevator's as you are on a matter/antimatter drive: as in "not at all".
We know the ribbon material (carbon nanotubes), we know the climber technology (trivial), we know how to dig a deep hole and pour concrete into it as a fundament. And that's about all there is to the Space Elevator.
Of course, a lot of smart people (plus politicians/lawyers) will have to consider where to build it and how to protect it from various dangers, i.e. sabotage, accident, weather, etc., how to achieve step 3 (profit!), and how to use it as the biggest sling there ever was. But the actual, biggest challenge will be to build it at all, which includes manufacturing the ribbon fibre in sufficient length and strength, and as far as I understand it, this is mainly an tinkering/engineering problem. The technolog is there, now it "only" has to be improved to a degree that we can start talking business.
The grass is always greener on the other side of the light cone.
The LiftPort Group of companies working towards a space-elevator are making a great deal of progress. Slashdot reported on the faa approval of their high altitude tests, for example. See here and here for more LiftPort specific information. Check here and here here for several reports concerning the viability of the elevator -- be sure to check the NIAC pdf. Blaise Gassend has a great collection of information. Finally, though carbon nanotubes are still in their infancy (its been a little around ten years since they were discovered) - their theoretical tensile strengths are perfect for application in a space elevator construction. This recent development spells a rosy future, and many innovations yet to come.
The proposal to take 12 years to replicate what we achieved ofer 35 years ago in only 9 years is ridiculous and excessively priced. The problem is that the engineering talent isn't at NASA anymore, they cant look beyond doing the same design that has been done over and over since von Braun, and the whole setup is just a welfare program for bloated aerospace conglomorates.
On the otherhand, the study that purported to show that a space elevator could be built for a few billion dollars is sheer fanasy. Single-walled Carbon nanotubes still cost hundreds of dollars a gram, and the price has not been falling all hat quickly in spite of the many uses we already have found. 600 million grams of them to make a first elevator will not be cheap enough to allow the projected budget to be met. Further, no one has made a macroscopic amount of any material that would meet the strength requirements of an elevator, let alone the density, weldability, splicability, or wear, oxygen, and electrical resistence requrements. The lasers for power are speculative and will certainly be unbelivably inefficient and costly. Even if microwave poer transmission can be arranged with suitably low antenna sizes on the climber, the cost for the floating base station off the coast of Ecuador alone would run more than the entir projected budget. It's just not an engineering option at this point. By all means give it a couple billion a year in research dollars to small, nimble firms like the one that produced the study. It's the best long-term strategy for space that's on the drawing board. But dont insult everyone's intelligence by saying the whole thing can be done in 15 years for $20 billion. Thirty years and $500 billion is a better guess - but still quick and cheap at the price.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
Counterweights won't work. As a car approaches the upper station, its weight diminishes to zero.
Therein lies part of the problem of resistance. Think of the old dogs working at NASA who are very good at what they do but possess specialized skills and knowledge that may not lend themselves as well to building a space elevator as they do to sending objects into orbit using current modes of transportation. Continuing education and cross-training is one thing; restructing job duties and/or phasing out unnecessary positions (such as those presently required for current trasport) at a governmental agency level is simply a can of worms waiting to be opened.
A worthwhile endeavor indeed, but the approach will have to be sent through 72 review committees and beaten to death where people eventually forget why they're meeting in the first place (aka death by committee) long before a space elevator ever develops beyond the gleam in a few visionaries' eyes.
This sig is six words long.
Did you know that elevators smell different to midgets?
This should hold true for space elevators as well.
...one giant leap for the first wise ass to press all the buttons (Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere...) and piss off the other astronauts.
--I'm so big, my sig has its own sig.
-- See?
How could any president reward his corporate donors with a low cost space program? Take a look at recent military or highway bills, there is more pork than substance. The only way to build space elevators is make them more expensive than rockets.
Strangely (sideline) I typed into google "when did man first land on the moon?" the first 9 results related to articles relating to theorys about it being a hoax, and the last was about a film in 1964. -- google needs to give better results than that!
...
Anyhow... my point was the Space Race which started ~1957 by 1969 the first mission to the moon began. From basically having little or no technology to do so resulted in Armstrong planting his footsteps on our lunar friend and quoting those famous words. It took 12 years for us to achieve such a wondrous goal. So how come its going to take us 15 years (goal being 2020) to do it again? (considering we are so much more technologically advanced than we were back then)
Nick
Electronic Music Made Using Linux http://soundcloud.com/polyp
I would prefer a space escalator. Just don't let the kids play on it.
Don't trust a bull's horn, a doberman's tooth, a runaway horse or me.
You want moot third usage (adjective) second definition (academic).
<teacher style="english">A spelling checker is no substitute for a dictionary!</teacher>
-Peter
Launch Loop presentation and Space Elevator presentation .
For large projects to be realized, they either have to be of decisive strategic/military value during war (Manhattan project), or they have to completely capture the hearts of the citizens that are supposed to pay for it all (Apollo Project, "before this decade is out..."). Clearly, for the Space Elevator, the latter is the case. I, for one, have not heard of Launch Loop before, and the dry PDFs and text files that are Google's #1 on the term didn't really invite me to care about it. The Space Elevator, on the other hand, has been part of the popular culture for decades, and has recently surged astronomically (no pun intended) in terms of mainstream recognition.
Just as it would have been more affordable and scientifically more valuable to gradually conquer space and ultimately the moon (i.e. with manned space stations and a launch from space etc.), it was the extreme appeal of the "moon shot", the giant leap that won the favor over the more economical approach.
The grass is always greener on the other side of the light cone.
Structural engineering issues aside, the big problem with space elevators is the junk in low earth orbit. If a 200 kg object hits the structure at a relative velocity of 15,000 MPH, it will release energy equivalent to one ton of TNT.
Wikipedia says nanotubes erode because of atomic oxygen in Earth's upper atmosphere. So much for that idea.
As a Slashdotter said once: build me a 40,000 millimeter bridge across a gulch on a campus, and then we can start to talk about a 40,000 kilometer bridge straight up.
So we're still four orders of magnitude from the point where we can usefully consider the remaining six orders.
...is that rockets/space shuttles garner much better publicity. Until they blow up, at least.
Enough with the space elevator already. How many dupes does this make? There was one just last week. Can they go a month without posting a stupid space elevator story. Anyway, it's not going to happen. We are more likely to see a resurgence in Zeppelin travel before we get a fucking space elevator.
Why not build a space escalator instead? With a sign that says "This way for all true believers and chosen ones!" Except when they get to the top they'll have suffocated because there is no fucking air. The bodies will be easy to dispose of because they'll burn up when they fall off. And a little sensor will trigger a small bell at the base with a sign below it that says: "Every time a bell rings an angel gets its wings!"
"You'll get nothing, and you'll like it!"
I've said it before and I'll say it again. There will never be an operational "space elevator" on earth. Before the miriad scientific, technical, logistical, political, and financial problems are solved, mankind will invent better, easier, less-costly ways to get into space.
- scsg
NASA's Exploration Systems Mission Directorate is already funding space elevator research - John Mankins who was formerly a big cheese at ESMD is a space elevator advocate. One of NASA's Centennial Challenges is to directly foster space elevator work. A Space Elevator is at the moment an idea. Building a space elevator with current technology and expertise may be even less practical than sending humans to Mars with current technology and expertise - much further work is needed but for space elevators the unanswered questions are arguably more fundamental. People love to criticize NASA and point out how company X, Y or Z already has capability A without considering that there are fundamental reasons e.g. to do with energy, systems scaling etc which mean that going to Mars is vastly more difficult than say a suborbital hop. Companies working on prototype space systems and tackling problems in innovative ways should be encouraged by they do not yet provide a certain path towards desired goals like putting people back on the Moon.
Prolog rules
> Elevate me up Scotty!
Best tautology on the board.
What about the in-built (iTunes) Muzak? Elton John - Rocket Man will be banned (should be anyway).
If the break was very near the groud where it's not moving it most would fly outward.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
I posted this on the Sunday /. space elevator article, I'm going to repost here.
Thoughts on Space Elevators [mit.edu] by Blaise Gassend has a lot of good info & links on space elevators
I'd really like to see a few of the numbers that go into that $6 billion computation. Given that the current contenders for the space elevator are too short by nearly a dozen orders of magnitude, and that's before you start to work out how you get it there, making sure it's safe, and the research issues we haven't even forseen yet.
IEEE Spectrum is a reputable journal, but it still sounds to me like the $6 billion is a fundamental number, i.e. pulled out of his ass.
Sure, I'd call for spending a measley $10 billion in a heartbeat, if I thought it would work. But I'm gonna need a lot more reason to believe it can happen than a microscopic black dot and a number I read on the Internet.
"No Buck Rogers, no bucks" is an old phrase used by Congress to describe why so much of the money in our space program goes toward manned space. The American space program was created to show off just how much Americans could achieve that other nations couldn't. Astronauts became not just heroes, but figureheads for NASA and the USA. A lot of people who lived through the space race got trapped in the mindset that those individual astronauts were what really mattered, and not the greater technological achievements.
Too many of our nation's legislators are those sort of people. They're afraid that voters won't be interested in robots exploring space or space elevators so those legislators only approve funding for more orbital flights, satellite flybys of nearby planets, and the occasional rover to explore Mars.
I think this will all start to change in another decade or two, when the majority of America's legislators grew up after the moon landings, and aren't as concerned with Astronauts as they are with science, technology, and exploration.
You know you want to. Before you post that brilliant point about why it can't be done, go read the faq and see how the respond to the million other people who made the exact same point. Maybe you'll buy it, maybe not, but I'm tired of reading "but what about hurricanes?" every time we have a space elevator discussion.
Or here's a more frightening angle: could a space elevator project be used as a rhetorical basis for a new imperialism?
The guy is a fucking moron. End of story.
Personally, I'd have thought it simpler to have a central spiral staircase in the building, acting as a sort of spinal cord. You then create a positive pressure in the staircase, such that smoke in the building will always blow AWAY from it, never towards it. (This prevents the chimney effect that causes so many disasters in tall buildings with continuous staircases.)
By locking everything onto that staircase as ribs, you should get a stronger structure than using the current pile-of-boxes approach.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
If you simply want to get cheap payload into orbit this decade using materials that are NOT theoretical, find a way to get funding to the blimp-to-orbit people at JP Aerospace.
Lots of things wrong with the Space Elevator concept... it breaking could kill a lot of people... but the dealkiller is that you can't build a structure with theoretical materials, and it shouldn't take a "rocket scientist" to figure this out.
Tech Public Policy stuff
Before calling thought out plans ridiculous you should consider you did'nt invent KISS.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Can be... could be... That's the problem. The tech isn't there. The carbon nanotubes that are long enough, aren't strong enough. The carbon nanotubes that are strong enough aren't nearly long enough.
The tech isn't there. How can they start building something that doesn't have the prerequisite materials? The current plan NASA is proposing they can start building **soon**.
The R&D you need to produce space elevators is currently being performed worldwide by a variety of companies and is well-funded. Diverting $100B isn't going to up the timescale **that** much. Not to mention while it looks good on paper, we haven't even tried a prototype yet.
-everphilski-
From TFA:
the best appears to be magneto-plasma-dynamic (MPD) drives which shoot out ions at 40,000 m/s
Ion drives are only useful in that they can be sustained for long periods of time. They're too weak for use in anything other than interplanetary space flight; they produce a thrust of about 0.01N.
all the way around the Earth's circumference.
Can someone please explain this to me. The cable has the same rotational velocity as the Earth. Why would it not fall straight down?
"I'm not impatient. I just hate waiting." - My Dad
The Shuttle gets the benefit of the ceramic heat-proof tiles, which would be unusable on an elevator cord, as the tiles are way too fragile to survive having a huge elevator clamped onto them. They'd crush. The tiles are also highly toxic, which makes getting out of the elevator somewhat awkward.
The potential difference between the ends of the cord is the biggest technical problem - you're going to get a potential difference great enough to simply destroy most substances at a fraction of the length required. You're going to have to solve that problem before you're going to get very far.
Building from space and dropping the cord would be disasterous - air resistance from a vertical plunge would destroy it. You're better off attaching the cord to a propellent-free vehicle and firing it up, as you'd have fewer heating problems. Air currents might be a problem (such as pushing against the cord, resuling in the vehicle plunging uncontrollably towards the ground).
Do I think it's better than NASA's solution? Oh, by a long way. I don't think it'll work, but it would advance technology considerably even if it fails to achieve its primary goal. NASA's solution won't advance a damn thing, even if it succeeds.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Rather than building a space elevator, why not explore linear motor technology to launch payloads ballistically? This has all the benefits of a space elevator - no need to take fuel with you, build it once and re-use as many times as you like, with none of the drawbacks, such as requiring 32,00km of exotic cable we don't know how to make positioned to fall on everyone's heads 3 times over.
A pizza of radius z and thickness a has a volume of pi z z a
All objects larger than (if memory serves) 10-15 cm in diameter are being tracked and catalogued by earth-based radar facilities as of today. So, if such a behemoth really were to pop into existence and to fall on a trajectory that crosses the hpothetical Elevator, counter-measures could be initiated. That's not to mitigate the challenge of Space Junk, but it's a risk that can be planned for and designed against, and it's nowhere as serious as your calculation implies.
The grass is always greener on the other side of the light cone.
Secondly, if you want to be rational about space elevators you have to face the fact that nanotube fibers don't yet exist but fibers like Dyneema or Spectra do. So what? Here's what:
With existing fibers you can build Hans Moravec's Rotovator(tm) which picks up hypersonic (near mach 12) payloads from an altitude of 100km and slings them to orbit.
Current proposals for implementation of the Moravec's design rely on a hypersonic air-breather of advanced aerodynamic design like the Boeing DF-9 (that exists only on paper).
Is there anything likely come along in the near future that could take paylods to 100km and mach 12?
Probably the same thing that is driving the technosocialist pundits to make all this noise about space elevators now:
A key to the Rotovator(tm) is getting hub mass in place to keep it out of the atmosphere while it picks up mass from 100km@mach12 -- but that mass can be any old space junk (what is the dry weight of the International Space Station?) -- at least at the hub where it counts the most for high strength materials like carbon nanotubes. However, you can do a Rotovator(tm) with off-the-shelf commercially available fibers and still have a factor of 2.
Nice thing about Rotovators(tm) is that they can be built with much lower capitaliztion over a much shorter period of time using existing commercial materials. All you need is a bunch of mass orbiting near earth, some quite-doable tethers, and sufficient manuverability and speed in the atmospheric leg to hook up with the tether as it reaches the nadir.
Modest prize awards toward early milestones of a space elevator could end up enabling the Rotovator(tm) as well.
Seastead this.
Overnight it would become the primary world terrorist target.
Oh, and yes, China would probably want one too, and they would get one sooner or later. Given that China already has enough ICBM's to make a mess of America's biggest cities (perhaps a dozen, which is more than enough), them having a space elevator represents no additional military threat. So we may as well sell it to them. One thing that people haven't quite grasped, however, is what the availability of nanotubes is going to do to mechanical devices *other* than the elevator. A whole generation of military equipment is going to be rendered obsolete instantly...
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
When the light begins to change
I sometimes feel a little strange
A little anxious when it's dark
I have a constant fear that someone's always near
I have a phobia that someone's allways there
Sometimes when you're scared to take a look
At the corner of the room
You've sensed that something's watching you
Have you ever been alone at night
Thought you heard footsteps behind
And turned around and no one's there?
Because you're sure there's someone there
Watching horror films the night before
Debating witches and folklore
The unkown troubles on your mind
Maybe your mind is playing tricks
I have a constant fear that someones always near
Fear of the dark, fear of the dark
I have a phobia that someone's allways there
When I'm walking a dark road
I am a man who walkes alone
Sometimes I think Merkins would be happier if they listened to their own Rock'n'Roll and thought about it...
The asteroid counterweight solution has the obvious advantage that the ribbon length is pretty much halved, because its center of gravity will be almost at its end (the asteroid); also, the asteroid obviously doesn't have to be launched into space in the first place.
On the other hand (and I'm not speaking as a scientist here), I can't easily imagine the difficulties involved in a) finding the right asteroid of the right size and consistency in a suitable orbit and b) changing its orbit and navigating it prefectly into the desired new geo-stationary orbit.
In my humble opinion, if you already know how to build a 36.000 km ribbon in outer space and attach a captured asteroid to its dangling end, then you might just as well go all the way and make it double as long, problem solved.
The grass is always greener on the other side of the light cone.
Somebody's been reading Red Mars recently; just because "science fiction" has science in the title, doesn't mean that any of the ideas explained are at all feasible.
No!
If we could assume zero mass we could just dangle a long piece of kitchen twine from geosynchronous orbit down to the ground.
The mass of the 'space cable' is incredibly important in calculations, just about everything except for a nanotube cable would BREAK under its own weight.. even the strongest steel cables can't cope.
Never mind trying to actually *lift* anything.
They have to be on the equator - because they end up in geosynchronous orbit .. which has to be on the equator.
Last time I looked, none of the USA is on the equator.
Damn, they'll have to start talking to countries on the equator (hmm - Panama all over again?)
No, the heck with talking to them, just invade.
"Cats like plain crisps"
The article claims that a space elevator could be built for $10 Billion.
Are they crazy? The REPLACEMENT cost for a space shuttle is ~$2 Billion, that doesn't count the construction of infrastructure to support it or the R&D that went into designing it.
No structures of any appreciable size have ever been built from carbon nano-tubes. Assuming that they work, that means that the entire space-elevator would need to be developed starting with the materials themselves. Not to mention all of the infrastructure and construction processes would need to be built/desiged to support the construction effort in the first place.
Only a complete idiot could even dream that this approach would cost 10 times what the new moon-shot program is estimated to cost, much less 1/10. This website lacks even the faintest hint of substance and believability.
The elevator has to climb the rope/ribbon. Even at 100km/hr that's 200hrs to geostationary orbit. Too slow to make passing through the Van Allen radiation belts survivable by humans.
Dodging freak weather is an issue which requires a mobile base station to manoevre the base of the cable. Similar mechanism is required to dodge space junk and meteorites.
Oscillations in the cable must be damped.
Cost per kg lifted is cheap ONLY if the initial capital cost is ignored.
This is just a few of the many gotchas. But this romantic pipe dream has grabbed the imagination of many who are prepared to (i) understate the problems and (ii) understate the cost. See http://en.wikipedia.org/wiki/Space_elevator
Paul Beardsell
How would a space elevator fall?
If we are talking about hte transport car becoming detached in atmosphere it would fall like anything else. Outside atmosphere it would depend on where o the trip and whether the perigee of its orbit were in atmosphere.
If we are talking about the structure itself that is where things get weird, and some one who know more about orbital mechanics can correct me.
Assuming it were severed low to the ground the center of gravity would move up. Causing the hanging portion to move relative to the atmosphere. Air friction would bleed off some of the energy and the structure would gradually descend as it moved. The center of gravity would eventually reach geosynch orbit again and the bottom would stop moving relative to the earth. Not sure what happens to an object with a center of gravity in geostationary orbit and a portion hanging in the atmosphere.
Higher up is more dangerous I suspect because the portion still attached to the Earth falls. And, then we have to deal with whatever it falls on. Not sure enough relative motion would exist between the air and the falling portion to result in burning. So, watch out below. In this case if the upper portion does not extend into atmosphere it would start moving relative to the ground. Ideally, the crew at the top station could move the counter weight to restore geosynch orbit, and eventually restore the connection to ground.
how would they deal with the section within the top most atmosphere? nevermind if something can withstand it, can it do it for more than a day let alone supposed years?
There are other approaches requiring less dramatic technological advances.
A simple approach is to start with a satellite at low earth orbit, then extend a cable up and down from there.
There are other approaches requiring less dramatic technological advances.
A simple approach is to start with a satellite at low earth orbit, then extend a cable up and down from there.
Ok. Now spin - get the speed right and you get a cable moving at a sensible speed at the bottom that could be grabbed by a passing space plane. You'd need to balance the masses at the two ends of the cable - but effectively you can transfer two objects into and out of high earth orbit.
The good part about this is that the cable is nowhere near the surface of the earth, and thus cannot suffer from wind, earth-based terrorist attack, etc.
As technologhy improves, the cable could be extended, gradually approaching the ground. Of course, when it reached the ground, it would be at zero speed - and there's your elevator.
"Cats like plain crisps"
I had a strange idea.. Please hear me out..
.. ok..
.. Why?
Instead of trying to lasso a friggin' asteroid. {excuse me.. still laughing}
Why couldn't we just build a "Bubble" of sorts out of diamond?
Here's the basic idea. We build a sphere/dome/donought shaped diamond structure - roughly 1 kilometer in diameter. Ok?
The "Bubble" would use the simple principle of bouency whereby the earth's atmosphere become the "counter mass" that pushes the bubble into the sky. Imagine a bubble in your cola with the cola being the atmosphere
The reason for a diamond super structure is because the "Bubble" needs to decompress the atmosphere inside of it. It become a giant vacuum inside. That's where the lifting power comes from.. DUH! So diamond would be needed to withstand the atmospheric pressure, upper atmospheric radiation and most importantly the cargo weight that will piggy back the bubble to it's upper atmospheric height!
We make the diamond is curved sheets using CVD (carbon vapor deposit). This is being done TODAY, the only need would be to expand the "ovens" that are currently pressing out tiny 4 carrot rocks.
The "Bubble" has got to be LARGE.. Friggin' HUGE!
So that it can carry thousands of tons (or more!) of cargo with perhaps a rocket that detaches at 100 miles up and takes the cargo to orbit or the moon.
Once hundreds of thousands of tons can be reliably taken to orbit and back.. We are a space faring people TRUELY! I also imagine getting back down to earth in the same manner with a smaller bubble..
Before my imagination runs away from me, is such a thing even possible??? Admittedly I have never taken physics so I have had problems calculating the weight to atmospheric displacement.
If such a thing *IS* possible.. The moon could be populated by HUNDREDS of thousands of people and not the hundreds we have only spoken about regarding the Space Elevator..
PHYSICISTS I NEED YOU!!
PS:Cheers
Smile.
There was recently a Daily Planet episode on TV that talked about this "skyhook" thing, where you would rocket up to a suborbital path, and this big rotating cable with a hook on the end of it would grab your ship and fling it up into a higher orbit. The hook satellite maintained station using the earth's magnetic field and solar panels, or something. (I think there was a Spider Robinson story with a similar premise, but I can't remember the name of it).
I think this is the kind of thing that will precede a full blown elevator. It is a lot more feasable with current means, more of a Spaceship One, "Let's see if we can't do some down and dirty engineering to get something useful working" mindset than a NASA, "We will put a 7-eleven on the moon by 2015" mindset.
A republic cannot succeed till it contains a certain body of men imbued with the principles of justice and honour.
Where the Fsck do you build such a device? What do you anchor it down to?
Bedrock? where? Can't be any place, where there are strong storms, prone to earthquakes, Volcanoes, etc.
there is only a small handful of available sites around the globe for the Anchor point. Second the amount of mass that will be tugging on the techonic plate is going to cause problems, possibly leading to earth quakes in that region. Between the mass of the station, and the force of that thing trying to shoot into space(trust me on this you don't want it balanced the other way), this thing sounds like it will kill us all. Forget looking for meteor's we will build one our self and crash it into the planet.
The base required for this thing to hook on to is not only going to be huge, but needs to be inbeded in a few hundred feet of solid rock.
i thought once I was found, but it was only a dream.
Motorola has shown the possibilities of nano-emissive displays
There was a slashdot article that mentioned the ability to use "Y" shaped CNTs as transistors.
and of course this article's reminder of the tremendous (tensile?) strength these micro-structures offer. Don't limit yourself to "space elevators". All sorts of new engineering/architectural possibilities arise.
Humanity is at a flashpoint. What will it be?
Its just a pie-in-the-sky dream, and will be for the next century(ies). We dont have bucktubes "thick as a hair but strong enough to lift a car". We dont even have them a meter long and strong enough to lift an apple.
Exactly. Wake me up when we have a carbon nanotube bundle as thick as my arm, and as long as my car. Then tell me how much it will cost to manufacture.
Then build a bridge or two out of it, to prove that it's as strong as the theoreticians think.
For comparison, the world's longest suspension bridge is Akashi Kaikyo Bridge in Japan. It has a main span of 1,991 meters, or under 2 km. It cost an estimated 500 billion Japanese yen (U.S. $3.6 billion) to build the bridge. It took ten years to build.
That's for a problem with well understood materials science, done under normal Earth gravity, with normal, terrestrial manufacturing and construction processes.
With the space elevator, people can't even agree on how big it has to be (either 100km, or 36,000 km, or somewhere in between), how strong it has to be, or where it will be built.
In any case, right now it's 50 times longer, and billions of dollars more expensive than the billion dollar bridge: and that's just the material's cost. We can't build a space elevator yet. Why?
If we don't have agreement on a design yet, and we don't have a materials supplier, and we don't have a budget, and we don't have a prototype, and we don't have a plan... how the heck is anyone supposed to build it?
Any decent engineer would throw those plans back on his client's desk, and tell them to come back when they had worked out exactly it was they wanted him to build.
A space elevator isn't going to be built until we have cheap, reliable, and available materials build it out of, until we have machines capable of building it, until we have trained construction technicians capable of operating those machines, and until we, in general, know and agree on what we're building, what we're building it out of, how we're going to build it, what it's going to cost, who pays for it, and who bears the liability for failure.
That day may come. But there's one heck of a lot of materials science that needs to be done first. Build a large carbon nanotube cable. Then build a cheap one. Then prove that you can build a few hundred thousand cables in a cost effective, time efficient process. Then prove that the cables remain strong and reliable under all adverse conditions. Then find a way to mass produce them cheaply and safely, without health hazards to the workers who build them. I doubt that will take less than ten years, probably more like thirty, before we've got the fundamental materials science for carbon nanotubes down.
Once we've done all that, we'll finally have enough data to decide if we can really build a "space elevator", and how much it will cost, and whether the costs will be worth it.
Wake me up in thirty years.
--
AC
Until we see some plan to place a substantial counterweight into an appropriate orbit, a space elevator is just a (carbon nano-)pipe dream.
We could either boost several hundred tons of material into place (a very expensive propostition), or capture a NEO asteroid of suitable size via robotic ion drive tugs and move it into place (a very time-consuming proposition).
But since all the attention is on constructing the cable, or selecting the most appropriate attachment site, it seems that this is all just a phantasm of techno-geekery speculation.
A serious plan to construct a space elevator would be considering how to anchor each of the ends of the cable, as well as the cable and lifter. Without all these components, it simply ain't gonna happen.
And another thing -- how will we keep the cable from intersecting the orbits of all the satellites currently in place, not to mention the orbiting ISS? The ISS can navigate around the path of the cable, but most of the satellites cannot, and sooner or later will come to intimate terms with the cable, at whatever delta-V the respective bodies possess.
The Pacific Ocean is mighty quiet in places, that is why it is called that. There is also an area in the Atlantic Ocean, called the Doldrums, where there is almost no air or water movement. Sailing ships used to get trapped there and had to row out. Also, you don't need to anchor the bottom end, just keep the tension in the cable steady.
Oh well, what the hell...
I apologize for the poor formatting - it always escapes my mind that /. doesn't automagically break for you, but you need to use the br tag, and of course I'm too smart for the preview button. :)
Time is an illusion, lunchtime doubly so. --Ford Prefect
It will have a 13th floor?
If you could reason with religious people, there would be no religious people
but were we able to create a nanotube as long as 1 inch yet? Seems to me we can do really small ones but we can't seem to get past a very small size.
I think we need billions of dollars of investment in upgrading our antimatter production facilities. The space elevator only gets you into orbit, antimatter can get you to nearby stars.
you're a physicist?
One might ask the same about you. . .
how could you use an analogy like "it took millenia to get from iron->steel->a few dm steel wire for bridges" when it took millenia to get from horse and carriage to the car...but then only a half-century to get into space?
How could you use an analogy based on two examples of terrestrial, wheel-based transportation techniques followed by a sudden jump to a completely different line of technology based on different propulsion along with a whole host of other unrelated technological hurdles (all of which have been things folks were working on long before the invention of the automobile, I might add) and seriously think it means anything at all?
please formulate a similar chart to the aforementioned.
What chart? All you've formulated is a large pile of non-cohesive anecdote that doesn't really argue anything.
your the kind of physicist who looks through microscopes not telescopes, aren't you?
Actually, I'd rather have a scientist who looks through microscopes talking about spinning carbon nanotubes into something like the cable of a space elevator, what with all those details with spinning microscopic molecules, crystalline structure, point weaknesses, etc. You can look at all the stars you want, but that isn't going to produce thousands of miles of spun carbon nanotubes or other future material.
Admittedly, this post will probably be disregarded by most /. readers and "editors". However, I think that I've made my point :)
As with packet-switched networks, it will simply never work.
Oh, wait...
Get thee glass eyes, and, like a scurvy politician, seem to see things thou dost not.--King Lear
We killed the X-33 which was suppose to replace the Shuttle, which replaced a working rocket system. Now, we have NOTHING. Best to get a working system in place, and then focus on the nice stuff.
Who modded you down? There are so many idiots here these days.
I prefer the "u" in honour as it seems to be missing these days.
Liftport addresses this quite nicely in their FAQ:
http://liftport.com/faq2.php#science2
# What if the ribbon breaks?
* How easy would it be to break?
Very difficult. The planned position of the elevator avoids hurricanes, lightning and other extreme weather. The ribbon is engineered to be twice as strong as it needs to be to support itself and any planned cargo attached to it.
* What if it falls?
The majority, the long end out in space, gains enough speed that it burns up in the atmosphere, with the lower portion falling into the sea. It will not fall on top of anyone.
* For the portion that doesn't burn up in a fall - what effect will it have on the environment?
Honestly, it will make a little bit of a mess. But New York City tickertape parades have made bigger messes. Comparatively it will put much less dust, dirt, debris and chemicals into the environment than wildfires of the American west, any one of the large expendable rockets, or a month of natural meteors hitting Earth. The ribbon is light (7.5 kg/km) so, any pieces that fall to earth will slow down, in the air, to about the same terminal velocity as that of an open newspaper page falling. It will not have enough momentum to cause mechanical damage when it comes down. We have considered other health risks such as inhalation of very small fragments and believe this will not be a problem but we are conducting studies to make sure this isn't a problem. Since we are aware of the possible problems now we can design the elevator to avoid these issues.
* How large a wave/disturbance would it generate?
The wave/disturbance would be nonexistent. As above, there just isn't enough mass, even in later, larger, ribbons, to generate such energy dispersion. There might be a small amount of light as a line in the sky as the ribbon burns up but after that it will be a few pieces of black film fluttering to Earth. Because of the size, distribution and winds, it is conceivable that only a few people would even see the event in any way and just as few would find actual pieces of the ribbon.
* How much warning would there be from the time of a break to the time it would take for the lower portion to come down?
Depending on exactly what happened it could be a few hours to weeks.
* What would happen to the surviving portion?
The ribbon that fell to Earth could be recovered for study but because of the amount and distribution it would be difficult to find many pieces. The pieces that do land would eventually degrade but not for a very long time. Keep in mind that this is mostly a stable form of carbon; it doesn't do anything. The debris would resemble long hair and would probably be broken up in interactions with animals, plants, wind, fish and waves. In fiber form it would be much too large to inhale and would probably work its way through a digestive system unaffected. The only debris we have any concern about is if it were reduced to nanotube size. This we don't understand yet so we will study this to see if there is a problem and then probably also design the ribbon to remain in larger pieces if it re-enters.
* What would happen to anything climbing the ribbon at the time it broke?
The short answer is that some payloads will fall (below the break and below 24,000 km altitude), some will enter low orbit (below the break and between 24,000 km and GEO) and some will be tossed to high Earth orbit (above GEO) depending on where the payloads are and where
they are looking at building a space elevator in a more northern/southern position which has nice cool water on a island. Keep in mind that it is not a coastline that is the issue, but that nice warm water that brings in major hurricanes. I find it funny that so much has been built in the gulf. That is one of the worse places to build our space systems.
I prefer the "u" in honour as it seems to be missing these days.
Pull on the string, it comes down.
How does it stay up there? If we keep climbing the string doesn't it keep pulling the anchor towards the earth, and thus out of orbit? Maybe I missed the bit where it talks about how to affordably keep the anchor up in the sky when we keep on pulling the string...
The rotating tether recycles energy from things going down. It also transfers energy in short times, like 20 minutes, instead of days. So you can do many payloads per day instead of days per payload. They don't need any amazing power transfer beams like the elevator. Really could be done today.
Check out spacetethers.com.
From TFA: It would cost about $6 billion in today's dollars just to complete the structure itself, according to my study
From the parent: I've heard a similar figure before, and it's amazingly cheap if you think about it.
From me: It's only cheap because it's the amount is at best misguided, or at worst an outright lie.
The worlds longest bridge was just completed in Japan: it cost 3 billion US dollars to build, and took ten years to construct.
The bridge was only 2km long. The smallest distance anyone says we need to reach space is a full 100 km; some people say we need 36,000 km instead.
If we could build a space elevator out of steel (we can't!), and if price scaled linearly with length (it doesn't!), and if we weren't building straight up (we are!), it would still cost around 50 * 3 billion or $150 billion dollars to build.
If the construction time scaled linearly (it won't; we've never built a space elevator before) it would take 50* 10 = 500 years to complete.
That's the time and cost to build a bridge as long as the shortest elevator, without any special R&D costs. That's well more than the $6 billion the article claims, or the $100 billion he says NASA is "wasting" elsewhere.
The article also claims that carbon nanotubes have been manufactured which a lift a car; this just isn't true. He's lying to make things sound good; carbon nanotubes may have that strength in theory, but no carbon nanotube has ever lifted a car.
Carbon nanotubes are currently an interesting research project, not a building material! I can't get carbon nanotubes at my hardware store; they currently only exist in labs, are too tiny to see, let alone build with, and cost more per unit volume than gold! The longest carbon nanotube manufactured to date was only 4 cm! Attempts to stitch carbon nanotubes together have currently ended up with fibres weaker than kevlar; far too weak for a space elevator.
We can't build a space elevator until we first get building materials that are big enough to actually see, let alone construct a 100 km chain out of. We'll also need a minimum of $150 billion dollars, probably much, much more. I'd say multiply the costs by 10 for using a brand new material (nanotubes, assuming can get them working at all ), by 10 for the human costs of untrained manpower, by 10 again for the uncertainty factor of a project that's never been done, and by 100 for working against gravity.
That's 150 trillion dollars; and I think that's a reasonably conservative estimate, all told. If we need the 36,000km version that some experts claim we need, instead of the 100 km that some people say we can get away with, the project just won't happen. Even 150 trillion is a lot; really. We could do a lot of other things with that money...
--
AC
Meanwhile, in the real world, here's the way it works. (Just to remind the typical Slashdot reader who rarely visits the place.)
1. NASA is part of the US government. It is part of a political organization and has to respond to political pressure. This is why mission control is in Texas. This is why there are NASA projects in every state in the union. The NASA budget is PORK. One of the main reasons that NASA gets any funding is to put PORK into the districts of members of congress who vote for it's budget. Bettering human-kind or the technical position of the USA is almost irrelevent to the existance of NASA.
2. The space elevator is a pure research project at the current time. It is not an engineering task like the Apollo project. At the time of Apollo there were already people in earth orbit. Going to the moon was doing more of the same, only bigger. At the current moment in time there is NO deployable technology to build a space elevator. In rocket terms, it is equivilant to the pre-Goddard era. Yes, carbon nano-tubes exist in the lab, but the longest nano-tube material in existance is a few meters long. No nano-tube structural components exist outside a lab environment. This is why a space elevator is research. To do a space elevator in a specific period of time would be more like the Manhatten project, and that is not going to happen (see point 1 above.)
3. Going into space is hard. NASA has about as good a track record as any group IN THE WORLD. If NASAs failures seem to be greater it is because they tend to do more projects and have more visibility. You get more press for loosing a mannned unit then for losing a probe, and only Russia and the US are currently in the manned space business. For example, no one is talking about ESA/England loosing the Beagle probes to Mars, but when you talk about the space elevator the subject of shuttle losses is always in peoples minds.
4. If you want to get people back to the moon or anywhere out of low earth orbit, the only viable choice at the current time is rockets. If you look at the history of the US and USSR/Russian programs, capsules seem to be a better bet then space planes. Capsule technolgy seems to be more cost effective and more reliable. It also makes sense to leverage off existing technology. Using variations of current rockets, like the Solid Rocket Boosters (SRB) and the shuttle main engine reduces both cost and risk and it shortens lead time. It might be better to build single a stage to orbit platform with new engines in the long run, but this would take more time and money to get results. (See point number 1.)
So it all makes sense if you put it in the right frame of reference. It may not be the smartest plan, but it can work. There are some really signicant problems, but they have nothing to do with space elevators or any other kind of pixie dust. The basic issue is funding. Manned space exploration will distroy the scientific component of NASA. I have heard, for example, that JPL is going to loose a huge number of people. I believe it. Given the Bush administration world view, space only exists for military expolitation and manned missions that are long on propaganda and short on science. Let's face it, there would be no push to go back to the moon if the Chinese did not have a serious commitment to go there. NASA funding is about PORK and politics.
And to add the final piece of perspecive, the Bush family is really big on unfunded programs that sound really important but to nowhere. The first Bush had a manned Mars mandate, if I remember correctly. The current one has this 'No Child Left Behind' program, which didn't work in Texas and seems to be having even less success at the national level. As long has the press is good, who cares? Guess what will happen to this manned space plan...
What happens if the Space Elevator gets outdated or it has to be removed for some other reasons?
That whole orbital elevator thing didn't work out very well in Megaman X8 or ZOE: Dolores, i.
As Arthur C. Clarke and Asimov and so many other have explained, the space elevator, AKA the Beanstalk, works like this:
A 24,000 mile elevator cable, a space port at geoosynchronous orbit, and another, what, multi-thousand mile cable that extends even higher with a massive counterweight at the other end, ie a captured asteroid. A BIG counterweight, moving at at different orbital speed than the station to stabilize the cable?
Did I miss something in the last few years? Did someone come up with a new wrinkle in orbital mechanics that does away with the need for a counterweight in a higher orbit to keep the cable tight?
Hopefully one day that bureaucracy will wake up and realize it.
If this would have been a comment on here about NASA, it's almost a certainity it would have been modded -1 within minutes. I know I, and several others have tried to talk about the ills of NASA being such a bureaucracy, but our comments get ignored.
So could we at least have a laser light show or something at the base of this thing to make it as fun to watch as a space shuttle launch?
Second, we're ignoring that expendable rockets have a lot of potential left in them. No one is using these rockets properly! By that, I mean no one is launching in volume. You simply can't get effective economies of scale with vehicles that launch at most a couple dozen times a year (or in the case of the Shuttle no more than 7 or 8 times a year).
We need launch frequencies on the order of several a day not several a year. Incidentally, this sentiment is echoed by Mr. Reynolds.
Finally, my take on NASA's current program is that they should have at the start ruled out some of the most aggregious bad practices like "cost plus" contracts (where the contractor is guaranteed a profit no matter how high their costs swell). If a company can't stomach the risk, they shouldn't be in the business. This indeed appears to be more of the same from NASA that lead to the frivilous exercises of the past three decades.
cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.
why not shoot for something a little smaller scale than a full blown elevator: Momentum-Exchange Tethers? This would make gettings things into higher orbit or out of orbit much easier, allowing the use of smaller rockets. It could also be used to very easily get things on and off the moon.
Then, a moon based elevator would be the next step...
-- Senior Software Engineer, Attorney appearance services, locallawyerapp.com.
We could name the base camp after Thomas Edison...
Bavarian Purity Law of Rice Krispie Squares: Rice Krispies, Marshmallows, Butter, Vanilla.
the problem is, tactically, a frickin space elevator is really hard to defend.
think sept. 11
and no this isn't a troll actually visualize part of a frickin space elevator falling into the ocean, or worse on a nearby town.
it makes sense to create vessels that are terrain or air/space navigable because bridges can absolutely cripple you if they're taken out.
Carbon nanotubes self collapse after about 60 some miles, as opposed to Iron's 2. When I say this I mean that the very best structure we could come up with would collapse if we built more than 60 miles of carbon nanotubes vertically.
Another problem is that our current refinement process for carbon nanotubes is anything from controlled. The space elevator idea will become feasable only when we can allign all the nanotubes in one direction and make them much longer (say 2-5 inches) than they currently are (fractions of an inch)
The Wikipedia article says otherwise... it says that 65 GPa - 120 GPa are the expected required strengths. And it says that 63 GPa nanotubes have been created, and 120 GPa are theoretically possible.
It certainly sounds to me as if it's well within the realm of possibility, and that's with no fundamentally new discoveries. The foolish assumption would be that 10 years of research and $100 billion would turn up nothing fundamentally new.
The US could do with some possession by the spirit of Thomas Edison. He saw things we needed, that were obtainable with years of work from the current technology, and he busted his ass to make them happen. It could be done again. Not everything has to be laid out with every piece pre-discovered before we set out to build something. Where would we be if he had said, "Well, hair doesn't work, and copper wire doesn't work. I guess you can't build a light bulb."?
Suppose you want to build a space elevator. A way to do this, is to launch a spool of "starter" cable into geosynchronous orbit, and wind the cable down until it reaches earth. So then, how to launch it? How about: with their new heavy lift rocket?
http://www.google.com/search?q=ibm "pixie dust"
"IBM today announced that it is using just a few atoms of "pixie dust" to push back the data storage industry's most formidable barrier"
From The Enquirer
[Fuck Beta]
o0t!
Why a space elevator? Why not start making buildings and sky scrapers with this technology first? We shouldn't be throwing the cart five miles ahead of the donkey.
created yet ?
2mm 3 mm I really dont know but thought that they where very small and making long ones rather difficult and costly?
I have always wonderered how a space elevator would affect global weather patterns. Would it not in essence ground the ionosphere?
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1. We are not within many orders of magnitude of being able to build a space elevator. Its a great concept, and maybe someday. But not now. We don't even have a concrete direction of research to procede towards it now. One might as well suggest that NASA start a project to, oh... build a time machine. Maybe they are even possible; I won't argue the point. But I sure know that we don't know what to do to even start working towards one.
2. One of NASA's most severe problems in recent years is starting projects that have no real chance of being sucessful. This has resulted in endless series of project cancellations. NASP (National Aerospace plane) was probably the worst, but there has been a long series of them. I find it a great relief to see a major new project that looks like it can actually work. Its been too long. And it is sorely needed if NASA is to ever produce anything new other than paper.
The author of this piece makes the people who started the previously cancelled programs look like down-to-earth practical types.
3. And finally. If the cost was anywhere close to 6 billion, there would be no need for NASA to be involved. Private industry could and would afford it. But since nobody has even a clue how to build such a thing, any cost estimate at all is nothing but fantasy. Heck, for the same 6 billion dollars you could solve world hunger and ensure world peace. I just made that estimate up, and I claim it has as much basis as any space elevator cost estimate. Heck, my estimate probably has more basis. At least I know how many people are involved. (If you want to quibble that 1$ per person is a bit low, that's just a small detail.)
Being an SE enthusiast and having presented at two of the SE conferences, perhaps I can provide some useful background.
The single greatest challenge to building an SE remains that of producing suitable material for its main structural element - the cable.
A practical Space Elevator requires a material of ultimate strength of at least 50 GPa. Individual nanotubes have been made with several times this strength, but no bulk material has approached it yet. Pure single walled carbon nanotube fibres of length 4mm or greater should produce a spun yarn with strength in excess of 100 GPa and such nanotubes have been produced in 40mm lengths, but not in useful quantities. Steel reaches 5 GPa, but has 4 or 5 times the density of CNTs and so only has a fortieth of the specific strength needed. Aramid fibres such as spectra, dyneema and kevlar come closer, but are only useful for lunar or martian SEs, not earth ones.
Almost all other issues, such as terrorism / securing the base station / wind / lightning / discharging the ionosphere / lunar and solar tidal effects / atomic oxygen erosion / radiation damage / collisions with the ISS / swarf infall / cyclic heating and cooling / broken ribbon fragments landing on people or damaging the environment etc. either turn out to be insignificant or are fairly easily solved with a little thought and effort.
The two problems that are harder to solve are: micrometeoroid impact and what has been called 'fratricide' -- where fragments from one SE failing hit other SEs. The likely solution to the micrometeoroid (mm) problem is to make the size and shape of the SE ribbon such that mms do not degrade its strength significantly during the lifetime of the SE. Fratricide is very hard to deal with and will require that ribbons be designed to be VERY unlikely to fail and that they incorporate ways to affect the paths of fragments.
Beyond these problems there remain numerous areas of investigation such as the fundamental 'mode' or shape of SE to use -- a single straight cable, or a loop, or a straight cable with pieces that are cut from the upper end. Will a material be available that will allow loops or constant-thickness cables (requires 96GPa strength) or must we use a tapered cable? How to design and, crucially, power and cool the climbers -- or will they be 'clingers' on a moving ribbon? But all of these things are engineering design choices, not impediments.
NASA has been active in funding and encouraging SE research, including several studies by NIAC (by Brad Edwards and Jerome Pearson in particular) and in promoting the Centennial Prizes for tether technologies.
Given the uncertainty in producing a suitable material, and despite my enthusiasm for SEs I believe that NASA should not yet commit any large budget to the SE, but continue its excellent efforts in promoting the idea through smaller means. It could, however, usefully commit additional funds to CNT research since any progress in high specific strength materials would benefit it even if this research does not result in material strengths useful for an SE.
I am not well studied in this space elevator thingamajig
So what happens to the elevator when a huge storm comes into contact with it?
I expect there are places that mitigate this, but everyplace has weather. Is this not an issue?
Or is this something we can rebuild quickly and cheaply if wiped out by a freak storm?
I do think it would be great to be able to take a ride in one. could put the space needle out of business.
Current record to beat - 102,800ft set by Capt Joe Kittinger in a US Air Force experiment in 1960
One of these days I'm moving to Theory - everything works there
Imagine how space travel would change thanks to a space elevator! Instead of building super expensive spaceships, that need to escape earths gravity... build a space elevator to a large space station designed to build ships in space! saves money on all that fuel, or the fuel can be used to take our ships farther!
I think the US wants to revisit the moon soon to make sure the Chinese don't take all the good base spots.
I agree.
I think that we should spend that $100 billion on building more cities below sea level.
Does it have to be a 'carbon' nanotube?
Is there something specific about that element that i'm missing?
A space elevator on earth would be a terrible idea. If it failed or were damaged in some way the destruction and loss of life would far outweigh any benefits of cheap access to space. A better place for that idea would be on the moon as a way of moving people, building materials, helium3, etc. to space inexpensively. The gravity stresses, and risks would be significantly lower. A spinning electrodynamic tether (space hook) in low earth orbit might be a cheap way for suborbital craft to reach space. "Might be" is hard to build a national space policy on.
One Random Meteor is all it takes to bring down (and up) a huge trail of destruction on the earth when the space elevator crumbles. For that reason (there are a lot of meteors in space and it doesn't need a big one to trash something as fragile as this) space elevators are a terrible idea.
If a plain did hit the structure, and it was an arrangement of cables, I
imagine the plane would be shredded like paper. I don't think aluminum would
be any real match for the carbon-nanotube cables. Of course, I'm just speculating here.
(besides, I am hoping that they would build this thing to withstand extremely high winds found inside t-storm supercells, hurricanes, tornados, or
whatever else Mother Nature decides to throw at this thing.)
Im curious as to how long a piece of rope would have to be so that the resistance of antigravity to gravity would hold it in place if it was to reach from outer space and touch earth. I mean if you had a piece of rope and it was touching the earth and you extended it a great distance it would have to reach a point where it would no longer tumble to Earth.
The lead would deal with gamma and x-ray (your two biggest problems in space), the graphite would stop neutrons (which I don't believe would be that common, unless as secondary radiation when the elevator gets bombarded) and the iron would stop charged particles - especially beta.
You've also got to consider that dosage would be proportional to time. I doubt anyone is thinking of a space elevator that's the same speed as the service elevator in a University. (Rumor has it that the reason professors look so old is that they decided not to walk up the stairs one day...)
If your speeds are comparable to any conventional launch/re-entry, you barely need any shielding at all. IIRC, most video clips I've seen on launches do NOT show astronauts wearing helmets, but just lead-lined balaclavas. The system I'd implement would be orders of magnitude more resistant, which means you could travel orders of magnitude slower and still not suffer significantly from radiation. (Ten times the shielding would mean you'd need to only go at mach 2.6 to get a comparable radiation dose to shuttle crews. Tough, but if the elevator is possible at all, this would seem to be a very doable restriction.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
A recent article in IEEE Spectrum (about a few weeks ago) had a good article outlining how a space elevator could be implemented, by one of its main supporters.
Create Gaint Balloons, as bigg as needed, lift the shuttle platform using the balloons; When the platform reaches near the edge of atmosphere, Let the shuttle go in space. Wont this be cheaper ? reuse the balloon gases using solar powered compressors. Or to the extreme use hydrogen balloons and use the same hydrogen to propel further up the atmosphere.
I once read an interesting article on computing. It pointed out that computing has advanced hugely faster than almost any other field---the typical comparison is how battery energy density has only gone up a small amount in the last few decades---and extrapolating from the increases seen in computing power to any other field is hopelessly naive.
I'm thinking you didn't read that article. You might want to. It strongly suggests that "magic pixie dust" is not going to be as forthcoming in more physically-limited fields. In particular, there is no guarantee carbon nanotubes---or anything, for that matter---will ever provide the required strength-to-mass ratio, much less rapidly enough to provide a viable replacement for NASA's current space capabilities.
Yeah, a space elevator would be spiffy, but would it be quite as spiffy if it took 50 years of research, leaving the US "space" program grounded for 40 years? NASA and the government want a replacement for the Shuttles they're pretty sure they can rely on coming online largely on-time, leading to a minimal space-capability gap. Space elevators do not provide that functionality; for all their coolness, they don't fulfill the program requirements.
Sure, I think we should look into 'em, but "kewl" doesn't trump "does what we need".
Wasn't it in Red Mars (Kim Stanley Robinson?) where the counterweight on an elevator was destroyed, and the falling cable wrapped itself around the planet causing mass destruction as it went? Glad I don't live near the equator...
And another thing - how do they envisage putting up the cable? Tying one end to the back of a Saturn V and lighting the blue touch paper? Winding it down from the counterweight?
Isn't this more like a prisoner's dilemma, since it's a free-rider problem? 'Chicken' is a coordination game, where the difficulty is to make sure that both sides pick the right weakly dominant strategy (i.e. both swerving to the right).
Oh I've been studying too much neoclassical economics. Someone shoot me.
Since the Moon rotates only once every 29 days or so, the cable would need to be so long that it would hit the Earth, in theory.
Also, in any location other than directly toward Earth or directly opposed to Earth (on the far side of the Moon), Earth's gravity would distort the elevator.
There is a way to place a space elevator on the near side of the Moon, by using the Earth's gravity to counterweight the "top" of the cable, rather than using centrifugal force.
This type of elevator has several advantages:
- It is much shorter than it would otherwise need to be, meaning it uses much less material in its construction, and the material does not need to be as strong as for a longer, non-Earth's-gravity-counterweighted cable.
- The cable goes through L1, one of the Earth-Moon Lagrange points, which is a node on the Interplanetary Superhighway.
- Material mined on the Moon can be lifted "up" the elevator, through the Earth-Moon Lagrange point, then lifted "down" the cable toward the Earth, and deposited directly into Earth orbit.
This last advantage is particularly, uh, advantageous, because such orbits are highly elliptical, and could even intersect the Earth or its atmosphere, which would allow material (e.g., the He3 that you mentioned) to be shipped from the Moon to the Earth without using any rockets at all!The only parts of the Moon that are in constant sunlight are perhaps a very few locations at the poles, which are useless vis a vis a Lunar Space Elevator (although this article proposes a non-vertical Lunar Space Elevator terminating at the Lunar South Pole that could be used to lift water (believed to be located there) into Earth orbit).(Note, however, that it's still longer than the Earth's Space Elevator.)
In fact, such an elevator's cable could be made out of Kevlar!
Search Google for more info.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
A Lunar Space Elevator cable would not have to be so long that it would intersect the Earth.
According to this article, it would have to be only twice as long as an Earth Space Elevator cable, which is not long enough to intersect the Earth.
This surprises me; I had thought that, despite the Moon's lower gravity, the ~29-day rotational period of the Moon would have required an extremely long cable, long enough to intersect the Earth.
Sorry for the error.
(That'll teach me to post without doing sufficient research first. [No, it won't.] Shut up.)
BTW, the Wikipedia article has a lot of additional info about a Lunar Space Elevator.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
The problem with promoters of this kind of fantasy technology is that they don't understand how engineering really works. For example, the Apollo 11 landing happened more than 40 years after Goddard flew his first liquid fueled rocket. In between there were many intervening rocket designs, each taking the technology a small step forward. And of course, there were many catastrophic failures along the way as engineers learned to deal with unanticipated problems. Even the most advanced technology is the end result of a long chain of trial and error learning.
So how would this work for the space elevator? No one has ever built anything like it before; it is many orders of magnitude larger than anything humanity has ever built. It can't be built on any scale other than full scale, and would have to work perfectly the first time.
Just because something is theoretically possible on paper doesn't mean that it is practical to build in the near term. After all, the THEORY of rocket propelled space flight has been known for over 300 years, since Newton.
they are looking at building a space elevator in a more northern/southern position which has nice cool water on a island.
Um, actually they aren't. The plan is to have the base on a ship at sea, near the equator, a couple hundred miles from the nearest land.
http://www.liftport.com/about.php
Boundless Expansion, Self-Transformation, Dynamic Optimism, Intelligent Technology, Spontaneous Order- BEST DO IT SO!
While the space elevator idea is cool and all, I see no reason to believe that it could actually be made. Sure nanotubes are great, but has anyone actually made what they are talking about. Sure nanotubes are long, tiny, and incredably strong, but has anyone made even a meter long ribon that could take the strain of being a space elevator.
Look at fusion, sure we know how it works but we still can't make it generate more energy than it consumes. So a space elevator is not a foregone conclusion.
I suspect that there are way more reasons besides material science that this thing is not a great idea.
I don't think it's part of their Millenium prizes.
Damn, I already moderated this topic. Now I'll have to log in with my sock puppet to comment.
Oh yeah! Iraq! Remember that? That was gonna be a cheap, novel way to achieve fantastic results if we ignored all those doubters!
My point is not to simply smear Instapundit, as he does that for himself everyday, but to point out there is a rather large groups of people in the chattering classes out there who beleave EVERYTHING can be solved by an all out push of all resources..
A war on Cancer/Poverty/Terror/Drugs or some other project to build a huge flipping pyramid of ego.
This is like when Minsky told a grad student to solve the problem of computer vision on summer break....
a terrorist target.
carbon Nanotubes are supposed to have several times the tensile strength of diamond but it is only on a microscale. We can't be arguing to work on the space elevator if the required technology isn't invented yet. The nanotubes must be aligned properly to give it the required macro-scale strength. And there is always the question on how easy it would be as a terrorist target... There's my 2 cents
I seriously doubt the skills of any engineer who spells "nucular reactors". TWICE. And I'm not a english-speaking citizen...
[]'s Carlos Cardoso - Becoming a brazilian ProBlogger, typo by typo
Aww come on man, who farted?
...because Plutonians are teh suck
- The laser light might be in a tight bunch as it leaves the laser, but going up it will get pulled around a lot by thermal diffraction. Even if the wandering can be held down to 0.1%, that's many miles of wandering up at 5000 miles up. How are you going to collect the energy from a beam that's randomly wobbling across many miles?
- We're talking on the order of TEN MEGAWATTS of energy delivered. That's only about 2kw per square foot average, which the ribbon *might* be able to stand, but what happens when the random wobbling ends up heating a small area of the ribbon? Remember, this ribbon is ultra-thin, so it doesnt take much heat to raise its temperature way up there, and IIRC carbon burns.
- There's never been anything that long ever made in one continuous piece. Not even 1% that long.
- Is there a way to bond together shorter pieces? Glue? Pop Rivets? Super duct-tape?
- Even if it could be built, the odds of something that long being *perfect enough* are vanishingly small.
- Assume you have some "rollers" pressing against the thin fabric. The motors are delivering about 10 megawatts to the rollers. Assume the rollers have perfect grip on the cloth. Then assume that a greasy seagull goes splay against the fabric. Lifter encounters the greasy patch, a little roller slipping occurs. Assume just 1% of the ten megawatts gets converted to frictional heat. What's the temperature the fabric gets heated to? What's the temperature and the temperature gradients going to do to the fabric? Nothing good.
- What effect does a a lightning hit do on the fabric? Nothing good. And carbon IIRC burns in air. Yipes.
Those are just a few major quibbles off the top of my head. It's a nice idea, but most likely has waay too many complete show-stoppers.I agree, if this can be done with Kevlar, someone should be trying it. Even if they just hang a mass on it as proof of concept.
In response to: "A space elevator could be between 10 and 2000 times cheaper than conventional technology and will force NASA to change just about everything they do. Hopefully one day that bureaucracy will wake up and realize it." Granted that the elevator would be that much cheaper, in itself, the sentence contains an enormous contradiction. It ignores the cost of changing just about everything that NASA does. Change is expensive. Not that it shouldn't be considered, but boosters always pretend it is free.
It is a good thing JFK is not alive to read all the nay sayers here. It took less than ten years from JFK's annoucement and landing a man on the moon. At the time he made his annoucement to put a man on the moon, it was all theoretical. Yes they had rockets, but having rockets and carrying a man to the moon are two different things. They used determination and research to put them there and that is what is needed now.
We have had a lot of advancements in technology and materials since the 60's, this should not be as difficult as the first time around. I am concerned with NASA's proposal and some of the outdated tech they plan on using. If we can clone a sheep, I'm sure we can build a space elevator. If the gentleman's estimates are off by a factor of five(5 x $10 billion=$50 billion), that is still half. The research itself will payoff in new materials and processes. The future is now if you have the vision to see it.
I eat Karma for breakfast, lunch, and dinner. That's why I don't have any.
I see a lot of comments from naysayers that are based on outdated technology and SE specs. A lot has happened in the last year or two, guys. White papers dealing with everything from cable design (a ribbon seems to be the answer) to weather to electrical charge have been published.
.htm
/space_elevator_020327-2.html
There are still technical problems, some of which we probably don't even know about yet. But there is a design for a cable of 40 - 60% CN that should be strong enough. CN mass production facilities are being built. NASA is taking the concept seriously enough that their guys are writing white papers.
It ain't pixie dust anymore.
http://science.nasa.gov/headlines/y2000/ast07sep_1
"The desired strength for the space elevator is about 62 GPa. Carbon nanotubes... appear to have a theoretical strength far above the desired range for space elevator structures."
http://www.space.com/businesstechnology/technology
"The hurdle to date, Edwards said, has been the commercial fabrication of carbon nanotubes. Both U.S. and Japanese firms, among others, are ramping up production of carbon nanotubes, with tons of this now exotic matter soon to be available. "That quantity of material is going to be around well before five years time. It's not going to take long," he said."
http://www.liftport.com/faq.php
Frequently Asked Questions regarding the SE endeavour, from LiftPort Group
(a LOT of very good info here, here's a couple regarding points I've seen here)
What are some frequent Space Elevator misconceptions?
"Nothing is strong enough to make a Space Elevator."
Carbon nanotubes (CNT), discovered in 1991, are almost certainly strong enough. Theory says that they are 3-5 times as strong as we need them to be, and laboratory measurements of their strength, though very difficult to do and not yet definitive, have shown more than half the strength we need.
The longest nanotubes thus far are measured in centimeters, not kilometers, and certainly not 100,000 km.
We don't need and are not counting on individual carbon nanotube molecules running the entire length of the space elevator or any significant fraction thereof. The individual fibers in a string or rope are only a few millimeters long, yet the rope has a large fraction of the theoretical strength of the fibers. This is even more the case with MOLECULES, several orders of magnitude smaller than a fiber. A diamond is said to be the "hardest substance in the world" because of the strength of the carbon bonds that make it up, but a diamond is not a single molecule. Likewise an SE could be made with CNTs just a few centimeters or millimeters long. (In fact, a CNT several centimeters long is a wonder; they're single molecules!)
"The elevator would be susceptible to a terrorist attack. "
First of all, it's important to point out that there will be more than one Space Elevator. We plan to build a second one immediately (using the first to make it much cheaper) and expect that the second will immediately be used to build a third, fourth, etc. An attack on any one ribbon is unlikely because of the anchor stations' isolation and the relatively small number of casualties that would result. Terrorists are unlikely to be able to break the elevator anywhere higher than 15 km or so; it can then be simply flown back down to the anchor by moving some of the counterweight mass a bit further out and will be back in operation in a couple of days.
The first anchor will be located in the equatorial Pacific 650 kilometers from any air or shipping lanes. The ribbon would also have restricted airspace around it. The ribbon and anchor would be protected like any other valuable piece
Sorry for the repost, some of the stuff got cut off before due to my Slashdot noobness. Feel free to mod my other post out of existence.
.htm
/space_elevator_020327-2.html
I still see a lot of comments from naysayers that are based on outdated technology and SE specs. A lot has happened in the last year or two, guys. White papers dealing with everything from cable design (a ribbon seems to be the answer) to weather to electrical charge have been published.
There are still technical problems, some of which we probably don't even know about yet. But there is a design for a cable of 40 - 60% CN that should be strong enough. CN mass production facilities are being built. NASA is taking the concept seriously enough that their guys are writing white papers.
It ain't pixie dust anymore.
Detailed info and links below. http://science.nasa.gov/headlines/y2000/ast07sep_1
"The desired strength for the space elevator is about 62 GPa. Carbon nanotubes... appear to have a theoretical strength far above the desired range for space elevator structures."
http://www.space.com/businesstechnology/technology
"The hurdle to date, Edwards said, has been the commercial fabrication of carbon nanotubes. Both U.S. and Japanese firms, among others, are ramping up production of carbon nanotubes, with tons of this now exotic matter soon to be available. "That quantity of material is going to be around well before five years time. It's not going to take long," he said."
http://www.liftport.com/faq.php
Frequently Asked Questions regarding the SE endeavour, from LiftPort Group
(a LOT of very good info here, here's a couple regarding points I've seen here)
What are some frequent Space Elevator misconceptions?
"Nothing is strong enough to make a Space Elevator."
Carbon nanotubes (CNT), discovered in 1991, are almost certainly strong enough. Theory says that they are 3-5 times as strong as we need them to be, and laboratory measurements of their strength, though very difficult to do and not yet definitive, have shown more than half the strength we need.
The longest nanotubes thus far are measured in centimeters, not kilometers, and certainly not 100,000 km.
We don't need and are not counting on individual carbon nanotube molecules running the entire length of the space elevator or any significant fraction thereof. The individual fibers in a string or rope are only a few millimeters long, yet the rope has a large fraction of the theoretical strength of the fibers. This is even more the case with MOLECULES, several orders of magnitude smaller than a fiber. A diamond is said to be the "hardest substance in the world" because of the strength of the carbon bonds that make it up, but a diamond is not a single molecule. Likewise an SE could be made with CNTs just a few centimeters or millimeters long. (In fact, a CNT several centimeters long is a wonder; they're single molecules!)
"The elevator would be susceptible to a terrorist attack. "
First of all, it's important to point out that there will be more than one Space Elevator. We plan to build a second one immediately (using the first to make it much cheaper) and expect that the second will immediately be used to build a third, fourth, etc. An attack on any one ribbon is unlikely because of the anchor stations' isolation and the relatively small number of casualties that would result. Terrorists are unlikely to be able to break the elevator anywhere higher than 15 km or so; it can then be simply flown back down to the anchor by moving some of the counterweight mass a bit further out and will be back in operation in a couple of days.
The first anchor will be located in the equatoria
You had me with you until "enforce it with a couple of Patriot missile batteries..." Now that's funny.
Please see:
l
http://www.isr.us/Downloads/niac_pdf/contents.htm
Phase I NIAC Paper
http://www.liftport.com/faq.php
Frequently Asked Questions regarding the SE endeavour, from LiftPort Group
Then all their base will belong to us.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Trains are a much more complex issue than your quick "soundbite" True a lot of tracks are disappearing. Back in the last 1800s the US built far more train tracks than needed, to places that could never justify having train tracks. Now that the car is universal, those tracks are being torn up.
However the tracks built where it makes sense to have train tracks are not only doing fine, they are expanding. The rail roads are building more tracks in places because they are needed. It just isn't 1990's "anything with a web site gets funding" anymore. (Except for the railroads anything with tracks gets funding was the 1880s)
Per ton mile shipped, the railroads in the US, ship the most freight of any country as a percent of total freight. However since freight is boring you don't see this.
Other countries send people by train. However people are time sensitive, so they upgrade tracks. The US just flies people around, doesn't cost much more, and for the distances it is faster than a fast train. Other countries give people the priority on their tracks, but that screws up freight traffic (which doesn't need the speed, but has to pay for it because the rails are high speed), so those countries send less freight by train.
Of course the facts don't allow for doom and gloom, so nobody notices them.
Tethers are cheaper, don't have to be at the equator, and can be used elsewhere in the system for orbital transfers. It's probably also harder to crash a plane into them, since they don't reach the ground (you rendezvous with the end via aircraft). They don't even need carbon nanotubes. You can make them out of nylon (IIRC, see papers at link).
I haven't been keeping up with the research but aren't there also modes where you have a shorter detached cable that's rotating? Think of an "I" with a hefty mass in the center. It rotates and, gosh, the velocity at the tip is close to zero as it brushes the surface. Think of a car's tires.
In this case you could climb the cable to the middle and be dropped in orbit, or hang on for half a rotation and be thrown completely out of the gravity well.
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
hmm, my post was flamebait wasn't it?..I was in a pissy mood I guess. I'm sorry.
IANAP - But I play one on the internet.
So, How could you use an analogy based on two examples of terrestrial, wheel-based transportation techniques followed by a sudden jump to a completely different line of technology based on different propulsion along with a whole host of other unrelated technological hurdles (all of which have been things folks were working on long before the invention of the automobile, I might add) and seriously think it means anything at all?
I don't think it was a meaningless example. True, it wasn't as linear an analogy as our Physicist parent's, but my point was to illustrate how human progress is no longer linear (if it ever even was). I think there is validity in my analogy - these are all ways of getting someone or something somewhere with increasing capability: forms of conveyance.
What chart? All you've formulated is a large pile of non-cohesive anecdote that doesn't really argue anything.
There are countless indicators of humanity's unprecedented recent progress. I should have made up some simple, snappy function to graph using the indicators I highlighted, but honestly that would be easily countered (as often are statistics). I thought I would step-back, and just try to look at the current state of technology as a whole as compared to the past. The light bulb is the fire and the nuclear energy is the firewood. I think they are comparable, at least superficially.
The microscope thing was dumb. I admit. I was just getting worked up, and this is the emotional outburst. I love microscopy, I put the electron microscope and the hubble on the same level matter of fact. And I love all physicists and scientists, even the pessimistic ones (it's just so fun when they are finally wrong about something!)
you see, my frustration stems from naysayers. It's so easy to nay, yes? I mean, most ideas and experiments fail in some way. Look how long we've worked on flight. How many people have said, "that will never work" and were right? Many, most in fact. But we flew. It just took the internal combustion engine to make it a reality. In fact, it took only decades after that engine before Kitty Hawk.
Nowadays I think of the computer as the new engine, and I really don't see why we it's so inconcievable that we could have the elevator within a half-century. Sure, betting against it seems safe, but do you bet to be safe? or do you bet for the maximum payoff?
What's wrong with dreaming?
No, you're just ignorant. I'll admit that the Patriot is way, way oversold as an anti-missile missile, but if you're in an airplane and someone shoots one at you then you're dead. Patriot was designed to take out Soviet fast movers in the NATO theatre of operations and all of its tests showed that it was very good at that. Taking out missiles is something that it was never designed to do, the Army decided to make modifications to it to try to get some SDI cash in the late '80s. The fact that they had some success is indicative of how well they engineered the Patriot as an anti-aircraft missile.
cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.
Why? They're anti-aircraft missiles. The fact that they didn't work too hot for something they weren't even friggin designed for (anti-ballistic missile) doesn't really pertain. If they can shoot down British fighters they can probably handle a hijacked commercial plane.
The more and more I research the space elevator the more and more I think to myself pet rock, molar's skycar, etc... I just can't buy into it any more as a praticle means of transporting anything outside out atmosphere. This technology is still in its infancy and the writter wants to take it from mere meters to the moon for less than 6B. I might as well make the claim that I can finish my wormhole research for 1B and that the government would be better to spend the money on that. NASA is using proven technologies to get to the moon and not attacking the project like some half assed "High Times" look at the situation. The strength of these fibers isn't quite there yet, less that 70% of the required strength. If anyone could say honestly that 6-10B later they would somehow majically get the additional 30+% isn't being honest the truth is they don't know how much it will cost. We know how much is costs to build rockets and the like we have been doing that for quite sometime. Even if you don't beleive we ever made it to the moon the first time, can you deny we have had astronauts in space? The trip from geosyncronous orbit to the moon is a lot easier than making the leap from 10 meters to 384 kilometers.
The design in TFA is a 1m-wide, paper-thin ribbon. A structure like that would be easily buffetted by a hurricane's 200mph gusts, causing it to rapidly twist and turn.
The problem is that nanotubes undergo buckling under torsional stress, which is exactly what that kind of twisting and snapping back and forth in strong, gusty winds would do. Worse, hurricanes can spawn tornados (waterspouts), which would place very high torsional stresses on the elevator.
Contrary to what you say, hurricanes and the intense torsional stresses they could apply to a thin, stretched ribbon might be a very serious problem for a space elevator.
(This is why plans for an elevator stick it in the eastern half of an ocean, since hurricanes and typhoons move east-to-west as they build. Regardless, this could be a potential problem, even for the weaker storms such areas get.)
Uh, One serious problem with the space elevator.. The ISS is not a Geo-Stationary Satellite. So NASA would have to design and build an entirely new Space Station adapted to the elevator. Unless we wanted it wrapping around the planet like an ugly game of tetherball. Personally, I think its a horrible idea, not that what is currently in place is better, but the NASA guys really need to get some better ideas. And hey .. 100$ billion, isnt that what Bush spent on the last war anyway? Sure its a lot to you and me, but not to the entire US of A. I wonder how many times your ears would pop on the way down? Hah!
see above comment.
Tech Public Policy stuff
What a useful device to fling snowballs and polar bears into orbit.
There is no America. There is no democracy. There is only IBM and AT&T and DuPont, Dow, General Electric, and Exxon
Space elevators as envisioned, are mostly cables that go from the earth, to an object orbiting earth to anchor them. The tensile strength required is enormous, and the design is "all or nothing". You have to get most of the object in space and lower it down. The cumulative weight would also be enormous.
What what about an elevator to an elevated launching platform? I've always thought that a heavy-lift blimp or plane could reduce much of the cost and size of engines. But if we had an eifel Tower structure that was perhaps 2 or 3 miles high, and the elevator lifted a space plane or rocket to be launched from that altitude... wouldn't we remove about 60% of the required lift energy? Perhaps we better engineering minds could calculate the cost/benefit ratio to achieve the optimal height.
What is the tallest, stable tower we could build? Assume just the weight of the lifting cable and a rocket (blastoff flame is directed at air and not the structure)? We can use mass damper technology to avoid acoustic and wind resonance that might tear down such a delicate and high tower. I would think 3 to 4 miles would be feasible. I just imagine that after the first mile or two, you get diminishing returns for how high the launch tower is. Saving 50% of the energy for launch would make a huge difference on the types of engines that could achieve orbit.
What do you think?
>>"ad space available -- low rates!!!"
Over the life of the Shuttle program (beginning in the 1970s) we have spent over $200 billion on it. And what do we have to show for it? Certainly not reliable, inexpensive access to space.
That that is is that that that that is not is not.
The first powered heavier-than-air flight was in 1903 but 11 years later, in 1914, surprisingly large numbers of planes began developing strange "bullet holes" and crashing to the ground.
~CGameProgrammer( );
> an ego-boosting "been there, done that" trip to the Moon
We're not.
"There are significant differences between the Apollo of yesteryear and the NASA plan of today, Spudis said.
In the first place, the systems making up the vehicles are being designed for maximum leverage: long-life, cryogenic-based propulsion, with potential reuse in space, Spudis explained.
Secondly, the mission is different.
"In Apollo, the mission was to prove we could land on the moon and return safely to Earth. In this case, the mission is to determine the best site to collect and use the resources of the moon and to emplace the necessary infrastructure to do so," Spudis said....
In point of fact, Spudis continued, "Apollo, for all its beauty, was essentially a technical dead-end ... one-use systems, storable propellants, a paradigm of launching everything from Earth."
Spudis told Space.com that this system, as blueprinted by NASA, is designed from the beginning to adapt to a different paradigm: the use of off-planet resources -- lunar-manufactured propellants -- to create a permanent transportation infrastructure in cislunar space, the territory between Earth and the orbit of the moon."
Maybe they should make verticle high altitude nano carbon rails on top of the higest mountain. First make a small hand bucket version maybe send fuel and supply to orbit weighing less than 50plbs but schudule 2000+ trips over the year.
Yeah, one of the googled articles mentioned that.
As the other person who responded to you wrote, such a device would have to be boosted each time it picked up a load from the surface, if it wanted to maintain altitude (which, of course, it would).
This could be done with fuel coming from part of the load it picked up, or from fuel loads picked up periodically.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
I would think that one would want the CG to be slightly on the Earth side of L1 in order to maintain some cable tension at the Moon base.
Otherwise, the cable would bob around and occasionally go slack at the end, which might not be too good if a car were being loaded onto the cable at the time, etc.
In addition, if the CG is on the Earth side, the cable would tend to be pulled toward the Earth, which would counteract the pull toward the Moon caused by full (heavier) cars traveling up the cable and empty (lighter) cars (if any) traveling down it.
Of course, the CG can't be too far away from L1, or the tension at the base of the cable might be so much that it would break.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
I would think that one would want the CG to be slightly on the Earth side of L1 in order to maintain some cable tension at the Moon base.
Otherwise, the cable would bob around and occasionally go slack at the end, which might not be too good if a car were being loaded onto the cable at the time, etc.
Depends what you mean by "slightly". A few km, maybe? Yes. But a few km out of 53,000 is piddling. A few thousand km? No way.
If the CG is significantly past L1, the cable will bob around more than it would at L1. The cable will be taut no matter what, as things aren't perfect (the elevator will likely be off-equator, and there are tidal considerations anyhow) but you still want it basically at L1.
There're simple rules in Larry Niven's "The Integral Trees" (worth reading) about orbital motion: "in takes you east, out takes you west" and "faster moves you inward, slower moves you outward". If you move the CG out from the Moon (closer to the Earth) it moves faster. It has to. The centripetal force increases - just look at the math.
As long as the body stays along the Earth-Moon line, F_c = F_e - F_m = Gm(M_e/r^2 - M_m/(d_m-r)^2. You're past the point where F_e = F_m, because the net force is pointing towards the Earth, otherwise it wouldn't be orbiting the Earth. Past that point, decreasing r (moving towards Earth) means increasing F_c (well, its absolute value). So it starts moving towards the earth and eastward. There's an opposing force at the base (tension), but it can't propagate infinitely fast, so the cable will start orbiting around L1. The amount that it orbits is going to be related to how far off of L1 it is.
The reason you might want it a little on the Earth side (a few km or so) is because the tension at the base can't restore the center of mass when it moves towards the Moon. When it moves towards the moon (out moves you west moves you slower) it'd be like trying to keep a kite up in dying wind without moving by tugging on it.
You'd also want it a little there because when you load the elevator the center of gravity moves towards the Moon, and so you want it to be able to take that load. But you're not talking about having the CG of the elevator significantly off of L1.
> Why? Whats the hurry? Would it really be the end of the world
> if we didn't get back to the Moon by 2020?
It would not be the end of the world. But since the "estimated" time of having a working space elevator is about 2020, it's a sensible target time for sending humans to the moon. This way you have both systems for sending humans and for sending cargo working at about the same time.
Ooooh handbags at fifty paces.
And you are exactly the wrong person to defend the elevator if you think anti-aircraft missiles will protect it adequately.
You are guilty of limited thinking, a fault in far too many involved in the defence industry.
I'm not ignorant. How dare you?
I was meta-modding and this is what i saw.
Stairway to heaven