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Thoughts on the Space Elevator 622
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."
Musak (Score:5, Funny)
Re:Musak (Score:5, Funny)
Re:Musak (Score:5, Funny)
I would think the biggest issue would be safety. Two shuttle breakups in 15 some odd years is bad enough, but what will be required when we really have the promised trip to space every week.
Re:Musak (Score:4, Insightful)
But ah beg to diffah. To be honest I can't think of anything safer than an elevator for 'point-to-point' space travel. If we can make a hair-thin cable strong enough to lift a car, imagine what weight a thousand of those strung together - say in five separate cables (not unlike today's elevators) - can assure. The cable's heaviest load, though, would be itself, and that towards its centre where Earth's gravity and the cable's own extra-gravitational circumferential pull meet up. Not to mention the additional stress caused by the cable's movements around its earth-fixed tether. But I'm sure that it's more than managable. <br/><br/>
Another plus would be the long-term costs - Once built a space elevator would cost its maintenance and the energy to get it up there - yes there are other costs but I'm sure you all get the picture. In fact, who says we have to get up there <i>quickly</i>? For humans to get up to that orbital satellite-maintenance station, sure, but what about the satellites themselves? These could use "slower" energy - and why not solar power - to take their sweet time getting up there. Things would speed up towards the top anyways. We already have freight elevators, don't we?
Re:Musak (Score:3, Informative)
-Jesse
Re:Musak (Score:3, Funny)
Re:Musak (Score:3, Funny)
Pixiedust (Score:4, Insightful)
Re:Pixiedust (Score:4, Informative)
It already exists. Just not for what you are thinking about using it for. IBM owns the patent on Pixie Dust. Although I can't see that they care about it anymore now that they sold thier hard drive division.
Re:Pixiedust (Score:5, Insightful)
The current plan doesn't get us to the moon until 2018 anyways, and without a cheap way to keep things flowing between here and the moon, the chance of a sustained human presence is nil. So we could spend $100B building basically the same propulsion-based solutions we've always been building, or we could spend a much smaller sum on fundamental materials research.
I don't see it as a gamble, because without a drastically cheaper way to get into space, we'll just retrace the journeys of the Apollo missions. Then the whole nation will kick back, pop open a beer, mutter "Yep, still got it," and wait to do it all over again in 2050.
Count me in with the pixie dusters.
Re:Pixiedust (Score:5, Insightful)
This may be true in the everyday world of cut-throat competition, but if we call this "optimal" and everybody does it, everybody waits two years, and nobody puts forth the effort to realize the gain in productivity. Leeching off of technology that hasn't been invented yet reaps the benefits of work paid for by whomever goes first. I call it a technologically-oriented game of chicken.
Looking more closely at NASA's past projects, you will find that NASA takes precisely that role - the government puts up huge sums of money on an unproven technology, and the world reaps the benefits years (or decades) later. From the taxpayer's perspective, the only important criterion is whether the indirect reward will pay back the taxpayer for the up-front costs.
Re:Pixiedust (Score:5, Interesting)
Re:Pixiedust (Score:3, Interesting)
A Lunar Space Elevator (Score:4, Informative)
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:
(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 [google.com] for more info.
Re:frick n frack (Score:5, Interesting)
think sept. 11
Bullshit, 9/11 happened because it was a one off, it's unlikely to happen again because who is going to believe highjackers who tell you that you'll be all right if you cooperate and don't resist. That's not likely to happen again. Also you can set up a no-fly zone for 100 miles or so around the elevator and enforce it with a couple of Patriot missile batteries for distance work and Vulcan cannons for close in work. We have bunches and bunches of people in all four services thinking about ways of improving "if it flies, it dies" technology and they'd love a chance to try out their stuff.
Re:Ahah. Ahahahahaa (Score:3, Informative)
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 decide
Re:frick n frack (Score:3, Informative)
Only the cables below the break will fall down. The rest of the elevator will fall up.
Re:frick n frack (Score:5, Informative)
See http://www.elevator2010.org/site/primer.html [elevator2010.org] and http://www.liftport.com/faq2.php#science2 [liftport.com] for starters, Google for more.
What really makes sense is an infrastructure that makes getting people and payloads in particular to and from space cheap and reliable, even ordinary. The only chance for that right now is a space elevator.
You have a 3% chance of death flying on a space shuttle. That's an incredibly poor record, and incredibly expensive.
Re:Pixiedust (Score:5, Interesting)
NASA is taking the correct approach. They are building something that they *know* works first. They can then work out the pixie dust^H^H space elevator next.
Re:Pixiedust (Score:4, Insightful)
Why? Whats the hurry? Would it really be the end of the world if we didn't get back to the Moon by 2020? Is this a critical mission whose failure would jeopardize national security?
No, its a 100 billion dollar PR stunt. The best argument you can make for it is that in the process we are developing new technologies and discovering new ideas, but in that case wouldn't it make more sense to go with the new untested but potentially revolutionary technology than what is effectively the same thing we used 36 years ago? Doesn't going with what you know works completely defeat the point?
It may be more cost effective technically.. (Score:4, Insightful)
Re:It may be more cost effective technically.. (Score:5, Informative)
A space elevator must extend to geosynchronous orbit, 36000 km up.
Re:It may be more cost effective technically.. (Score:5, Interesting)
Re:It may be more cost effective technically.. (Score:3, Informative)
Re:It may be more cost effective technically.. (Score:3, Informative)
It would be like Jungle Hunt, but without the alligators.
Re:It may be more cost effective technically.. (Score:3, Informative)
A variant on a space elevator, it's basically something in orbit that dips down and gets a package from orbit.
Re:It may be more cost effective technically.. (Score:3, Informative)
I don't know why I have to post this information on each space elevator thread (you'd think people would have gotten it down by now), but here we go again. The strongest measured SWNTs thusfar are just over 60GPa; most were lower. Most space elevator designs call for >100GPa; probably the cheapest and most thought out plan, by Dr. Bradley Edwards (of Liftport fame), calls for >120 GPa.
It gets worse
"Unobtainium" (Score:3, Interesting)
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. H
Re:"Unobtainium" (Score:3, Insightful)
Re:"Unobtainium" (Score:5, Insightful)
Basically what we have is a difference of attitude. I see "we have the engineering figured out for using 65 GPa ribbons for a space elevator, and we can produce material now that could almost theoretically have that strength, and in theory we could produce materials almost twice as strong" and I think, this is something that needs research. I am not claiming that 10 years and $100 billion will build a space elevator - I'm claiming that it could put us in a position to know how to build a space elevator, so getting the real funding becomes politically feasible.
You see the same statements, and throw up your hands saying we can't do it. Your arguments that we can't do it are pretty damn weak...
So your position is that we could almost do it with the materials we have now, on a 15 year old technology, if we had the right compositing process, but that it's ludicrous to think that we could actually do it with 10 more years of research focused on improving strength of individual tubes and processes for producing ribbons?
Comparing this to alchemists' dreams of lead to gold is beyond laughable. Assuming that you know more than the researchers dedicating themselves to this research is ridiculous. Assuming science and engineering will go backward rather than forward is demonstrably false. Asserting a strawman argument about bond strength is a red herring. And repeated commands to "deal" (by which you mean adopt your pessimist philosophy) are obnoxious.
Re:"Unobtainium" (Score:3, Interesting)
Yes, because you've refused to discuss any potential way at all to make them stronger, and instead have just insisted that "it can be done" without evidence. I was bringing the discussion back to the real world.
"we have the engineering figured out for using 65 GPa ribbons for a space elevator
No, we *do not*. We have the engineering figured out for *rare min
New mission (Score:3, Informative)
> an ego-boosting "been there, done that" trip to the Moon
We're not. [msn.com]
"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 cou
Re:It may be more cost effective technically.. (Score:4, Informative)
If you read our literature (blog, press release, articles - heck you can write and ask) you'd discover we're not testing ribbons at all.
What we are doing is testing lifter technology. Sending a bot up and down in a reliable fashion is one of those easy-until-you-really-think-about-it deals. A whole lotta picky engineering needs to be ironed out to make those work in a reliable fashion.
Re:It may be more cost effective technically.. (Score:4, Informative)
It gets worse. That's the strength for individual tubes. Bundles are around 20GPa currently. They're limited by VdW and pi bonding. It gets worse still, however, because the best bulk fabric isn't as good as individual bundles, and are only (5-10) GPa. And even that's not ready for mass manufacture. Notice how many orders of magnitude this is off from what is needed.
Can it be improved? Yes, but not that much. Individual tubes can be made more consistant, and potentially have higher tensile strength (although probably not the earlier theoretical predictions) by tube type selection and refined production methods, but there clearly are major limits on this, and even those things will likely take decades of research before we can approach what their limits are.
Bundles can be improved by longer tubes, but again, they're not going to be stronger than the tubes themselves - only weaker. Getting long tubes (which will strengthen how tightly the tubes end up adhering to each other overall) in a mass-producable method is not going well. The way tubes today are assembled, be it CVD, electric arc, etc, is that the tube is extruded from a gathering sphere of condensing carbon, and it seems to be limited in its capability to grow. Short tubes can be merged, but that makes getting good tensile strength even harder. Instead of the problematic method of using long tubes to maintain bundle strength, you can do pressure-induced intertube bonding (trade sp2 bonds for sp3), but that'll weaken your tube tensile strengths.
In short, both problems, incredibly difficult or even potentially intractable by themselves, help defeat each other. Even with the best of luck and most dilligent research programs, with current tube-strength measurements there's not much hope for a realistic strength fiber any time in the forseable future, if it is even physically possible at all.
Elevate me up Scotty! (Score:2, Interesting)
Launch Loop (Score:5, Informative)
Re:Launch Loop (Score:2)
Re:Launch Loop (Score:3, Informative)
Re:Launch Loop (Score:5, Informative)
This is still a fantastic idea for getting things up, though.
It's just getting back down that runs into the same old problems (and comming down from space gently is one of the best (most overlooked) features of a space elevator).
Its nicer to repel than base-jump.
Re:Launch Loop (Score:4, Informative)
Re:Launch Loop (Score:3, Interesting)
difference between the two: (Score:4, Insightful)
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.
Re:Launch Loop (Score:3, Insightful)
Re:Launch Loop (Score:4, Insightful)
Sadly, the US isn't building much of anything anymore. We're a nation of managers and businessmen, not engineers.
Because most of the US lacks the basic knowledge set to even understand how a space elevator will work, or the trained imagination to envision what to do with it, the subject is incomprehensible to our citizenry.
We don't even build REGULAR trains anymore. We've deemed them dinosaurs used by the poor or the shipping industry looking to capitalize on a dying infrastructure, and left the rails to rot in a free-market grave. Maglev? Americans want a faster Mustang. They care nothing for trains, and never heard of maglevs in other countries. We think MONORAILS are stupid, even tho they are far superior for public transit than the 19th century horrors in Boston, New York, or Chicago.
I don't see America ever considering building a beanstalk.
Here's what I'm hearing and reading about the NASA back-to-the-moon program, as a for-instance: We went there before, over thirty years ago. Why go again?
This is not a field of dreams for building a fantastic SF future. Look to Japan, to China, even to Europe, maybe, for the human future in space. Far-sighted Americans will flock to those projects. But they will not be built in the US. We're lost in a dream in which the 1950's never ended, oil is cheap, we're the biggest dog on the block, and cars are the main means of self expression.
Re:Launch Loop (Score:4, Informative)
Re:Launch Loop (Score:4, Interesting)
private ventures (Score:3, Informative)
Hmmm.... (Score:2, Interesting)
Re:Hmmm.... (Score:2, Interesting)
After reading "Red Mars" I don't think it will matter where you build it. If it comes down it will leave a path of destruction all the way around the Earth's circumference.
Besides, the termination point needs to be easily accessible or you negate much of the advantage of having the elevator.
Re:Hmmm.... (Score:5, Informative)
negliable if built correctly. The local winds wouldn't have enough kinetic force to move the cable much.
Re:Hmmm.... (Score:3, Insightful)
Hurricanes aren't solely destructive because of the wind. A lot of that destructive power comes from the things the wind is carrying. At a minimum you have water, which makes the wind a bit dense. But in reality, you have all sorts of debris. Roof shingles, plants, etc.
Carbon nano-tubes have great strenths, but most things under linear stretching don't require a lot of lateral impact to cause them to break.
Re:Hmmm.... (Score:3, Informative)
You would be building this very close to, if not on, the equator. Hurricanes do not form there, and I can't even think of one that has ever crossed the equator.
Re:Hmmm.... (Score:4, Insightful)
I'm just glad we never built a Sears Tower or an Empire State building or a Golden Gate Bridge. Those kinds of things would get knocked down constantly if they existed. Damn terrorists. Can't hardly go outside anymore.
What about rescues? (Score:3, Interesting)
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.
Re:What about rescues? (Score:2)
Re:What about rescues? (Score:5, Informative)
Re:What about rescues? (Score:2)
It's not that kind of ladder. It's a lot more like a rope.
Re:What about rescues? (Score:3, Interesting)
nyet-o-tubes (Score:2)
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.)
Re:nyet-o-tubes (Score:2)
But instead time and money is spent on revamping the Apollo capsule (nevertheless, a good revamp to be fair).
Re:nyet-o-tubes (Score:3, Insightful)
It's probably a lot cheaper to "revamp the Apollo capsule" than it is to insist on such a great leap in tech, that tech being more of a curiosity at the moment than anything else. Taking things too radically different is what got us the Space Shuttle, when
Doom and gloom (Score:5, Funny)
Fear of the Dark (Score:3)
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?
Re:Doom and gloom (Score:3, Funny)
Re:Doom and gloom (Score:3, Insightful)
Re:Doom and gloom (Score:4, Insightful)
Tiny, successfully concealed bombs are more of a concern now than suicide hijackings, but those won't pose much of a threat to space elevators as long as official flight paths require staying away from them.
Longest Carbon Nanotube? (Score:2)
Article in IEEE Spectrum (Score:5, Informative)
Re:Article in IEEE Spectrum (Score:3, Informative)
What's especially amusing is that I (I'm actually the editor of the IEEE Spectrum space elevator article) submitted the original article by Edwards twice to Slashsot, once on the day of its publication, and then again when researchers announced a breakthrough in producing carbon nanotube ribbons in Science. Clearly my error was in not realising that slashdot readers would much prefer 2nd-hand references to articles 6 weeks after the fact.
Actually, I
Burn up (Score:2, Informative)
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.
Re:Burn up (Score:2)
Re:Burn up (Score:2)
For example, the shuttle travels around the earth onces every 90 minutes, making it's speed about 12,000 miles per hour relative to a fixed point on earth.
the counter weight is traveling at 0 mph compared to a stationary point on earth.
it won't have enough speed behind it to generate much friction.
Re:Burn up (Score:2, Informative)
So no-one is able to speak aloud about it?
Ooooooh, you mean moot [reference.com]!
</pedant>
3? (Score:2, Insightful)
Space elevator musac? (Score:2, Funny)
It's going to be one hell of a long ride and I'd hate to overdose on strings.
Re:Space elevator musac? (Score:5, Funny)
Yes and No (Score:5, Interesting)
Re:Yes and No (Score:4, Insightful)
Re:Yes and No (Score:3, Informative)
New rockets are engineering work: we have all the materials we need to use, we know all the physics that describes their behavior, and so as you said there's a clear (albeit expensive) path to figuring out how to put it all together.
A space elevator would still require science work, because the central pro
Engineer's perspective (Score:3, Funny)
another engineer's perspective (Score:2)
Re:another engineer's perspective (Score:3, Funny)
Therefore, a system with two cars and pulleys will always be almost in balance. The actual force in the rope will change depending on where exactly the cars are, due to centripetal forces.
The 'almost' is due to taking up more stuff than you are bringing down, or the other way round if you are mining a solid naquata asteroid, or due to a load of gold plated latinum as payment fro
Re:Engineer's perspective (Score:2)
Money (Score:3, Insightful)
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
I dont get it... (Score:4, Insightful)
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...
Re:I dont get it... (Score:5, Funny)
I say we put $12bn or so into nanotube powered teleporters. who's with me!?
Re:I dont get it... (Score:4, Insightful)
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?
seriously, what's the average velocity of a horse and carriage vs. the average speed of an orbiting body?
now juxtapose that over that timeline...
and what about energy? we had fire to heat us for millenia. then within decades of the light-bulb we have nuclear reactors.
please formulate a similar chart to the aforementioned.
your the kind of physicist who looks through microscopes not telescopes, aren't you?
Re:I dont get it... (Score:4, Interesting)
The things which are coming will blow your mind, but a space elevator with nanotubes isn't happening any time soon, despite what any historians may tell you. Contrary to what the "article" suggests, NASA IS working on this technology. They have spent a huge amount of money trying to get someone to grow a rope of continuous nanotubes just 1 meter long. Some of the best people in the world at nanotube growth are working on this (and have been working on this), and it will take a few years yet before they actually do it. Consider that two nanotubes tied (welded, bound, woven...) together are nowhere near as strong as one continuous nanotube. Consider also that nanotubes grow at around 10^-5 meters/s. Geosynchronous orbit is about 3.6*10^7 meters away. Here, really is the fundamental problem if we're going to try to grow a space elevator. If you go through the math, it would take about 10^5 years with today's technology, which makes the prediction of centuries very optimistic. I think it will take less than centuries (as in, I think we will find new growth or welding techniques), but there may be better ways of getting into space.
Logically speaking... (Score:2, Interesting)
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 cons
So, lift a car first. (Score:5, Insightful)
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".
A matter of time (Score:5, Informative)
Re:A matter of time (Score:3, Insightful)
I live in a place where a former leader was taken in by a cure for cancer, a fake hydrogen car that generated it's own fuel from water, a commercial space launching site that was going to be set up by a two person company and various other scams. Is LiftPort promising a return in the next decade when not even the basic material exists and is thus a snakeoil scam - or is it a serious research group taking the very long view and letting all pot
The elevator study is flawed, NASA is cowardly (Score:2)
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
Did you know.... (Score:2)
This should hold true for space elevators as well.
That's one small step for man... (Score:5, Funny)
KE = 0.5 * m * v^2 (Score:5, Insightful)
from the lab to working product... (Score:5, Insightful)
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 [jpaerospace.com].
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.
can be... could be... (Score:3, Informative)
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-
Space elevator funding is short sighted. (Score:3, Funny)
Re:Why the Space Elevator looks cheap (Score:2)
not as big of a problem as most people think.
OTOH,most people have no idea what it takes to do something, and are completly oblivious to the waste produced by the private sector.
If you look at the public records for most agencies, you will find surprisingly little waste.