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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."
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..
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
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.
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
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?
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".
I don't think that's the right way to think of it. Call it stepping stones. There's no point in abandoning short term projects for a long term one. There's no point in completely abandoning known working tech for something that's totally theoretical.
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 Soyuz+Mir and Soyuz+ISS has been doing far better, being older tech yet.
So far, despite the significant amount of research, I don't think the nanotubes have been made in kilometers, never mind 33000 kilometers or whatever it is necessary, and there are a lot of logistical issues.
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.
Which is SO possible with 20 year old technology, considering we are today still struggling to build maglev TRAIN tracks without them failing, not to speak of a 2000km long track into space . I always love how so many stuff is claimed to be "perfectly possible"...
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
...is that rockets/space shuttles garner much better publicity. Until they blow up, at least.
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
Well we still need relatively cheap heavy launch vehicles to build the space elevator in the first place, so I don't see working on an apollo type project as being an incompatable goal.
Can you be Even More Awesome?!
something of this magnitude would be a favorite target of terrorist or anyone looking to make a point
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.
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
No, but I'll bet a 2x4 at 90 miles per hour will.
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.
Make a bunch of them. They're less attractive as targets if there are dozens or hundreds of them.
The US may have trouble building maglev trains, but the rest of the world hasn't.
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.
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.
65GPa is only the "expected required strength" if you want to have a 12fold or higher taper factor. If you want that, you can't claim that it'll cost as much as a shuttle replacement (already a bogus claim, though, with even Edwards numbers estimating 40B$). You're looking at costs measured in the hundreds of billions or trillions at that weak of a strength, for a small elevator. Hardly an economic decision. Not to mention, ribbons that are 65 GPa still aren't close to existing. What we have are 5-10 GPa ribbons (even *those* aren't in mass production), and there are some bloody serious difficulties in getting past that, if it's even possible.
the foolish assumption that 10 years of research and $100 billion
People have been trying to make unobtainium since the beginning of time. Since we've started messing with nanotubes, our expectations of their physical strength has gone *down*, not up. Yes, in *theory*, they could be as high as 120 GPa. In practice, the strongest we've found is just over 60 GPa (like I stated previously). Deal with it. Deal with the fact that when you form them into bundles, they get weaker. Deal with the fact that mass scale production doesn't even gain that level of perfection.
The tech just isn't there. There's no shortage of research, yet, there's little budging on these fundamental limitations. I've explained the chemistry of it - what's your magical solution to get around it? Can you make the sp2 bonds stronger? Can you increase the strength of pi and VdW bonds? In short, can you alter the laws of physics? What's your answer?
"Edison" didn't try and break physical laws. Edison worked on engineering problems, and at most, unknown areas of physics. Edison didn't try and change physical constants.
I hate it when people just assume "there must be an answer, and someone smarter than me will know it". No, there must not. For millenia, alchemists tried to turn lead into gold and make themselves a fortune. They spent huge amounts of resources on it, with some of their brightest minds taking part on the work. Guess what? No lead to gold. Even with our ability to manipulate atoms, the best "lead to gold" that we could accomplish via nuclear collisions would make the price of gold look like pocket change.
Also, I can kill you with my brain.
Building a space elevator "away from civilisation" makes no sense - the thing is 36000km long (and more!), it could potentially wrap around the Earth two or three times on its way down (Kim Stanley Robinson addressed this in the Red/Blue/Green Mars trilogy). Though we might have some mercy from the thing burning up on reentry.
Without all those alchemists trying to make gold, you wouldn't have your precicious chemistry now.
People learn a lot by trying and failing. I'd rather see the money spent on materials science than re-doing something we already know how to do. There is a reasonable chance we will find a way, there is a reasonable chance that serendipity will strike and get something even *more* valuable out of the research, or we might fail but learn a whole lot of valuable information in the process.
Personally, I don't think we should be spending *any* money on going to the moon or building space elevators until we get our spending under control. Bush is spending money like a drunken sailor's wife. He needs to stop spending, raise taxes and cut the budget and get the hell out of Iraq.
So, how many planes broke up in the early years of man-made-flight? I don't know the numbers but I am positive its more than 2 in 15 some odd years.
Its just part of the development. by the time space travel becomes a daily, or even hourly, thing the safety will be to 'acceptable' levels I am sure.
Terrorists aren't going to be crashing planes into buildings anymore. The only reason they got away with it the first time was b/c the passengers didn't know their plans, and the ones who did, on the flight that crashed in Pennsylvania, fought back. From now on, for any hijacking attempt, the passengers and crew will assume the intent is to crash the plane and fight back. Everyone knows the rules have changed and that cooperation and passivity = death.
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.
Flying is easy, just throw yourself at the ground and miss. -Douglas Adams
Your post is a funny : )
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?
No, no sig. Really.
ThePromenader
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.
first to make the cable, you have too start in space naturaly, and as you make it, to get the cable to land at the cable connection on the ground, its center of gravity has to be in geo-syncronous orbit, which means the middle of the cable! so you have to make the cable twice as long as you need.
I think the idea is to have a large body serve as an anchor in space. Either getting a small-ish asteroid or lifting tons of sand into orbit, which would have to be done the old fasioned way.
secondly the cable is supposed to be made out of carbon fiber nano-tubes. these fibers are insanely conductive and flamable, think of it as a lightning rod, 44,960 miles tall!
I'm sure a coating or lightweight sheath can be developed. Pretty much any cable in use today is not simply a strand of white steel. They are often treated and coated to deal with harsh environments (marine, artic, etc).
third the cable has to be connect at the earth's equator, a band of lattitude not known for it's geo-political stability
How about a ship? A ship also affords some stress relief as it is not fixed and can move about.
Remember, You are unique...just like everyone else.
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.
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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