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Notes From 3rd Annual Space Elevator Conference
colonist writes "The Space Elevator: 3rd Annual International Conference was held recently. Blaise Gassend, a PhD student at MIT, took notes. The main obstacle is still the material: transferring the strength of the nanotube to the ribbon. Other topics include: the nanotube tether Centennial Challenge; Elevator 2010, a challenge for a 250 kg climber to climb a 16 km tether; objections and refinements to Bradley Edwards' design; non-equatorial space elevators; replacing the term 'space elevator' with 'space bridge'; testing the space elevator material on cable cars; science; defense and economics."
I sure hope their wont be a floor for the earths center, cause thats where you'll be goin if you fall off.
As someone completely new to the subject, I would appreciate any good introductions to space elevators. Does anyone have any good sources?
Yeah humans tried this once before and look what happened.
This will change everything. Transporting to space will be (relitive to rockets) DIRT CHEAP. Props to them for their vision and their crazy idea that just might work.
i always thought this was a cool idea, anyone remember that really weird book about this? that rocked. if you still dont get the point its that there will be a space station at the top and the elevator can shuttle up space ship parts and people. and i hope they have at LEAST polyphonic elevator music by then as all the current stuff sounds like monophonic ringtones on an old kyocera cellphone.
How on earth are they going to cope with the wind forces, the jetstream, gravity, the earths spin, earpopping, in transit entertainment, lightning, costs, kids, aliens, terrorism and the fact that their's nothing in space to go up to yet.
P.S.
EMACS already does this.
May the Maths Be with you!
They'd die on the way up!
I had an imaginary sig once, he said I was a loser and ran off.
Yea, try reading Terry Pratchet's the science of Discworld. He dedicates almost an enitre chapter to space elevators. The whole idea behind it that it takes a massive amount of energy to go to the moon, so its really expensive. The idea behind the space elevator is to send material down from the moon, at the same time hoisting something up from earth. Thus once its built, it will maintain itself, i.e no more billions to get to the moon.
But does it run Linux?
A sonice the comic issue i once had. A moon was tethered to the earth using a huge metal chain. Sonic run up it etc, save the world etc. It was a good issue.
I had an imaginary sig once, he said I was a loser and ran off.
ISS is at about 400Km.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
Anyone saying stuff about the thing falling down upon us should really read up on how a space elevator physically works...
or don't.
I can just see this thing, composed of composite carban nanotubes a million miles long, stretching into the atmosphere.
How are they going to design it so that a bomb can't destroy the precious tether?
Its not space we haven't conquered but our violence.
ls
The point is that it's an extremely energy efficient way of hoisting stuff into space (in theory).
Better to have a comparably near zero cost elevator than spending gadzillions launching a moonbase into space piece by piece using rockets.
The space elevator is a great idea but no human has the mental strength to listen to elevator musak for the length of time the trip will require and still retain their sanity.
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
I think that it should be taken into consideration that almost every major project of construction was deemed impossible. Very good examples of these are the famous Golden Gate Bridge and the EuroTunnel. Everyone said it was impossible, yet they were completed. As technologoy in this area continues to develop, I think that this may be able to become a real and practical idea sometime down the road. It may not be possible now, but in ten years, who knows?
That's because it's so expensive to get stuff up there. A space elevator would solve that (albeit at great initial expense no doubt ;)
Boffoonery - downloadable Comedy Benefit for Bletchley Park
Before we can take on a project of this nature we really need too solve a large number of more pressing problems. As I suspect you Americans may be beginning to realize, a big thing like a space elevator is likely to be vulnerable, and to be quite honest: the answer to all security problems isn't bigger guns, more surveillance and less personal freedom.
Think about it - as long as there are people out there that are willing to fly a passenger plane into a tall building, we shouldn't create an even bigger target. It was bad when the twin towers fell, both in terms of human life and longer term consequences, like pollution etc. If we suddenly have 100 miles of superstrong material slamming down at hypersonic speed, it's going to be extremely bad - somebody ought to calculate how many Teratons of TNT that corresponds to.
if a large mass was required to tether the ribbon to, would it not make sense to attempt to use all the junk in orbit of the planet instead of trying to send something up there?
I had an imaginary sig once, he said I was a loser and ran off.
I believe the point is to make access to space economically practical. Burning massive amount of fuel is pricey and pretty bad for the environment. If we really want to be doing stuff in space we either use space elevators or wait for someone to invent anti-matter drives or something.
---
We spoke for about a half an hour. I don't recall a thing we said. - Colorblind James Experience
And then you get modded up by others who doesn't keep up?! :-)
Please RTFA/RTFM etc.
Karma: Excellent (My Karma? I wish...:-( )
It just doesn't feel like bona fide space travel to me.
The owls are not what they seem
Blaise Gassend's page mentions Andrew Price's list of alternative names:
space bridge
space way
space rail
'Space bridge' got the most approval from the audience.
Forgive my ignorance, MEMS and Nanotech has fascinated me for a while, but I don't know enough of the math behind them to tell if this is true. My grandfather, rest his soul, once told me of something called the Sailor's Rope Rule, which effectively says that the weight a rope can support is diminished by its length. Thus, a 500 lb. rope might support 500 lbs when there's less than a foot or so in length between the pully and the weight, but might only support 250 lbs when there is a good 100 ft. or so... The actual support degradation of course depends upon the width of the rope and the material the rope is made of.
So what I'm wondering is, does the same apply to the weight supported by nanotubes and other molecular chains. I figure it has to be less of a degradation due to the ionic bonds involved, but it would seem to me that, unless some Quantum rule is involved dealing with extremely small-scale weight supporting chains, that they might never overcome this problem due to the sheer thinness of the tubes, chains, etc. It might be extremely strong material, but if it's width is only a few atoms wide, wouldn't this material be, at least in single lengths, more or less useless by the time it got to a respectable length? This is, of course, excluding bundles, which make the most sense, I'm really just curious if the same rule applies to nanotubes as applies to rope.
-The Libra
"Please be patient--The future will begin momentarily."
Not in the fairytail....
But there is archeological evidence for a lot of towers in what is now Iraq and Iran.
Among them some very big ones in babylon.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
Sorry. It was funny.
Karma: Excellent (My Karma? I wish...:-( )
Took 200 years for Napoleon's EVIL plan to be realised ;)
16km is a little too high for a helicopter (they top out at about 7-8km), but it's well within the reasonably altitude range for a large helium baloon.
Some people believe in the strangest things.
Here's simple for you: Low earth orbit requires a tangential speed of around Mach 25. Centrifugal force pulls up on the cable, the earth and gravity pull down. Nothing accounts for that 18000 miles per hour of tangential speed. If you take something up 200 miles on one of these and let it go it will drop like a brick, not to mention the cable colliding with any orbiting satellites that aren't geosynchronous or carefully postitoned to avoid it. The super-strong material required for the cable is the easy part. Remember, kids:
1. Convince venture capitalists you have a good idea.
2. Take money to work on the idea.
3. Reveal that the idea is impossible/really hard.
4. Go wallow in the money you "spent" working on it (Profit!).
Yah, if the counter weight(?) comes off, flies safely in to space, but the ribbon would still be pulled down to earth!
Besides, if the counter weight hits Mars we are in deep sh*t with the little green men.
Baloon? http://vpizza.org/~jmeehan/balloon/
If amateur home made ballon gets 79 809 (feet / kilometer) = 24.3257832 km then multimillion funded carbon nanotube project could make or buy a ballon that could work as counter weight. The problems from winds maybe dealt with small jets attached to it. And problem with fuel... Hmm use another balloon for refuelling. And make balloon REALLY big, as the weight of balloon and the surface area for wind grows R while lift grows R so you could get better fuel ratio for bigger balloons.
Emacs is good operating system, but it has one flaw: Its text editor could be better.
soo ... what's this 3 body problem then? ... ... well is cheap and the tech. is ...
i mean like
body one = earth
body two = space bridge
body 3 = moon
body 4 = sun
also note that this tether supports extrem forces
in one direction only.
i dunno, but having a superconducting coil in a
pod cooled by liquid oxygen and hydrogen, with the
waste cooling gases uses for further acceleration,
plus putting this pod on a nice linear
accelerating motor and this all near a pretty cool
hydrodam
available already, no 200 GPa material research
needed
i mean serious, linear motors and a pod with
enough hydrogena and oxygen, that combusted give
sume nice thrust plus rain add some super
conducting coils onboard pod, come on people
think!
/me slaps the mods /me cowers in fear
Imagine, once this thing has been installed, being the one with a too heavy spacecraft, pulling the entire thing from the sky.
That would suck...
According to new Nasa research http://www.nasa.gov/news/highlights/index.html they can fully fund a new US$2 billion research project by selling the franchise to the revolving restaurant at the top and logo placement along the length of the ribbon itself. Already, they have received competitive bids from Chez Panisse, McDonalds, and Bert Farnsdale's New York hotdog stand. This is the start of the holy mothership of bidding wars.
consider coffee a lubricant that helps one penetrate the coding zone
Oh, come on people! that's got to be funny!?
-gazillion STUPID!
at least you used AC, for not getting it totally you should be karmawhacked to hell.
your own writing has even a contradiction, you say the cable moves at the end at quite a nice speed yet you say it doesn't.
The Spaceward Foundation is creating the Elevator:2010 program:
Assume we have that 16km long fiber and solved the problem, that the fiber won't curl up around earth.
We lift up some cargo to the remote point, let it rotate until it faces the desired destination -- and then cut off the fiber and let the cargo flow accelerated by earth rotation. Might be interesting for probes where travel time is not a real issue.
And if we do it with lot/heavy enough stuff, then we even get longer days as a side effect :)
</sci-fi mode>
there IS being work done with shorter tethers, however the proposed SE will be some 100,000 km long with a small counterweight at the end.
They have to be to hold the darned thing in place. I doubt something as feeble as a passenger plane crashing into it will do much damage other than making it vibrate for a bit. I don't envy the people on the plane, though.
Stick Men
Heading Notes from the Third Annual Space Elevator Conference
AND
Below Keynote speaker, John Mankins line says
Projector died. Talk went on without it.
haha
Striving to be common...
Lets try a thought experiment. Imagine you are spinning on a barstool (a.k.a. the earth) and your legs are sticking out (a.k.a. the space elevator). If you extend you legs or the space elevator further from the axis, your rotational speed decreases. With the barstool example, you slow slow down along with your legs. A space elevator cannot change the speed of the earth's rotation, so it would wrap around the equator when you tried to launch anything of significant mass.
http://www.thebps.com/backgrounds/Elevator_1024x76 8.jpg
And that is the trick:
You have a big counterweight in geosynchronous orbit. The mass you launch is significantly smaller.
Once it gets up there it is also in a geosynchronous orbit and you simply let go of it and it will stay in orbit.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
Oh yeah? Just wait 'til the acceleration stops. (duh-dunt--tssshhhh!) Thank you folks, I'm here all night - try the roast duck!
"He who throws mud, loses ground." - proverb
I recall Arthur Clarke pitching the initial concept for a Space Elevator some time back, and revisited the idea in 3001 : The Final Odyssey - in which he depicted planet Earth having a fully functional ( four actually ) space elevator system; which facilitated a subset of human civilisation living in low earth orbits in reduced gravity - thus invoking presumed benefits of doing so.
Anywho. He spoke a couple years ago, subsequent to 3001's release on how at the time of writing, such a feat was nigh on impossible at this stage - as the materials to construct the 'elevator' were yet to be developed. Until now. The carbon molecule Buckminsterfullerene ( C60 ), also known as 'Fullerene', is supposedly strong enough to actually make such a concept a reality - which is in part the reason the space elevator was hurled back into the limelight of late.
I think its a fascinating idea - which until we develop propulsion systems beyond the primative scope of the 1,000+ year old firecracker concept, certainly seems a more elegant way for the species to venture into Space more regulary. Or, at the very least, be the catalyst for what could perhaps become the initial stepping stones to establishing a permanent presence in space which will hopefully later lead to space initiated launches.
What happened to the intermediate designs that don't provide all the benefit but also don't require two decimal orders of magnitude performance improvements? I didn't see anything in the
Brin's electromagnetically boosted tether design (Tank Farm Dynamo, 1983) would reduce the amount of delta-vee needed for orbit, at least allowing for cheaper shuttles. It's not much of a benefit, but we could build it today.
A rotating tether that dipped into the atmosphere would allow much greater safety margins and have a much less dangerous failure mode. You could practically rendezvous with one from an X-prize vehicle, and you wouldn't need to build a climber... just grab the tether, hold on for one rotation, and let go.
The big problem of course is that extra delta-vee isn't free, and the tether would lose altitude every time it's used (this is a problem for all tether designs, really). So, the throughput rate would be limited by the time needed to re-boost the tether between launches: using a high-efficiency low-thrust drive would be cheapest but require the longest "recharge" time.
Longer term, it would get a boost from de-orbiting mass from space: if you return a ship of the same mass to Earth at the same time as you boost one to orbit the net delta-vee is zero. If you have more ships going up than coming down, bring a nickel-iron asteroid into orbit and just feed a chunk of metal that weighs the same as the ship in from a higher orbit, it'd get de-orbited and released at 100km. Make it in an airfoil shape (a crude glider) and you can recover it... just deliver it to an asteroid-iron junkyard out in the middle of New Mexico or something.
THAT would make Rutan's barnstormer spacecraft a stage in developing a new industry, instead of a stunt.
It still moves the center of mass away from the earth, making the cable move slower. The earth will continue to pull on its end at the same speed, causing the wrap-around effect. The massive counterweight makes this happen more slowly, but it still happens. Something has to account for the tangential speed of the mass that you're launching, and until now it has been a horizontally-aimed thrust vector.
We can't change its name to be a 'space bridge'. If we did, we couldn't have the same hilarious jokes in every Slashdot article about elevator music.
Won't somebody please think of the hilarious Slashdot jokes?
The America / "The West" actually gets off its backside and builds it before China decides to.
Ripping an new rectum in the fabric of spacetime.
Why do we want to build a space bridge instead of a space elevator? Do we really want instantanious transport to Cybertron to get involved in a multi million year old war?
Following up to myself: here's a link to a page about a variety of tether-based designs and experiments: Advanced Propulsion Concepts.
The text of Tank Farm Dynamo is online.
And what if the tether breaks and drops on Earth: a wire so small you can almost not see it, but stronger than any other material. It will acts as a knife and cut through almost everything. A sweeping tether could make a whole area unhabitual. Very dangerous stuff.
Its always an AC who sets up these fucking whores for karma, so its no suprise who is posting these lame ass karma baiting gay questions. Fuckers.
Something I never heared anybody about: Where does the kinetic energy come from that the cargo gains when ascending into orbit? Somehow the cargo needs to gain a huge amount of kinetic energy, because the top of the elevator moves several km/s faster then the bottom. If nothing compensates for this energy, the counter weight would gradually slow down and deorbit, so there must be some kind of propulsion in the counterweight, pushing it prograde whenever cargo ascends and pushing retrograde when cargo descends. Anybody got more info on this?
Think about it - as long as there are people out there that are willing to fly a passenger plane into a tall building, we shouldn't create an even bigger target.
"Mechanical Engineers build weapons, Civil Engineers build targets"
Seriously, There will always be someone ready to answer the challenge. Brave men and women have always rise up to the challenge, some have given theirs lives.It WILL be done. If not in this lifetime, then maybe a couple of hundred years.
Why? Just like the mountains. Simply because "it's there"
I live in Soviet Canuckistan you insensitive clod!
It doesn't have to hit the ground, does it?
:P)
Still, yeah, hadn't thought of that. That's probably a better idea. (Imagine if you got a team being really ambitious when it comes to speed, ramming into the ISS when they hit the top of their cable.
Before this gets too far, somebody should call NORAD and ask them how many of the 2500+ satellites and other odd bits of junk traveling at 17551mph (LEO) cross the Equator (ascending and descending nodes) and might present a collision hazard. I could be wrong, but shouldn't the answer should be "Almost all of them."
This reminds me of the asteroid/comet problem, the probability of a significant impact might be low, but it only takes one.
The only problem is that earth will slow down if you launch enough mass (provided you don't bring any back down)..... Big deal.
The wrap around myth has been debunked ages ago, do a little google search on it...
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
erm...you do know that what you call an elevator we Brits call a lift? You do? Good, just checking.
Boring Old Fart (40, married, 3 kids...er no...make that 49, married, 3 grown up kids...it's been a long time)
While Arthur C. Clarke certainly popularized the idea of a space elevator in his science fiction novel "The Fountains of Paradise", the original concept is credited to the Russian engineer Yuri Artsutanov, who published it in 1960. See, for example, here
Ubi dubium ibi libertas: Where there is doubt, there is freedom.
There are thousands of other targets which would be far, far easier to hit than a physically tiny (in cross-section) ribbon hundreds of miles off the coast of South America (or Australia, another possibile site that's been considered) - not to mention the ease with which such a target could be defended by declaring exclusion zones around it and patrolling such with warships.
If you're going to launch a missile at it, could you identify where such a substantial missile is going to be constructed and launched; they are not trivial engineering projects. In any case, the missile would have to be targetted very accurately to give it a significant change of damaging the ribbon (particularly if you use your brain and anchor the ribbon at multiple points such that the loss of any one anchor point won't result in the loss of the tether). If these supposed terrorists have nuclear weapons, we have bigger problems.
And a conventional military attack on the ribbon would be dealt with the same way as an attack on any other possession of a soveriegn nation - you go make war on the people who've done it. And while the US has demonstrated that it's not very good at dealing with insurgency, it remains rather handy at destroying conventional militaries.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
Go try a merry-go-round some time. The further your center of mass is from the axis, the more rotational momentum the system has. Seeing as the elevator is moving mass away from the Earth's center, the whole system should slow down. The elevator has a pivot point at the earth's surface which will bend because the earth is much more massive than the rest of the elevator. Google was less than helpful with "space elevator wrap".
A merry go round is a very bad example for orbital mechanics....
By moving the center of gravity of the elevator around the geosynchronous orbit you can slingshot yourself pretty much to any orbit you want using the pivot point on earth as a lever.
You would need some energy to move the mass around though... (For instance using solar panels on the counterweight to move a small piece of it to a higher or lower orbit along the cable) This energy makes up for the energy you loose by letting the stuff that goes up go.
Its not a problem at all and would be negligable in comparison to the corrections you would have to do anyway to keep the thing in the right spot.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
My web domain.
In the effort to increase public comprehension of this concept, I offer up "space yo-yo".
The sailor's rule only applies when the rope is hanging down, it has to support its own' weight, yadda, yadda, yadda...
But, you see, this rope will be hanging "up" so to speak, and therefore conveniently bypassing any such rule. If my calculations are correct, since this rope is going in the negative direction, its strength will increase, rather than diminish, by orders of magnitude!
If you don't know what AltaVista is (was), get off my lawn.
I once had an asses debris problem but being on earth, gravity helped keep it discrete. I guess in space the lack of gravity makes it more of a problem. No one wants to share a space elevator with a "happy crapper."
It take more faith to believe in evolution than it takes to believe in God
This is the kind of stuff that Indiana Jones spectacles are made from . Actually, its kind of entertaining watching the currently known truths about Jewish and Sumerican history being woven into a Stargate episode...
A balloon as a counterweight? Am I missing something here? Correct me if I'm wrong but a balloon only has buoyancy when it's in a fluid. After a certain height the atmosphere is too thin to produce any more upward force, no matter how large your balloon. OTOH, maybe you are joking.
Quite an experience to live in fear, isn't it? That's what it is to be a slave.
Harsh? Yeah.
--- Ban humanity.
Hey-- I think we should leave the name as "Space Elevator". As we've all learned from a certain television show, the "Space Bridge" is only good for travelling to Cybertron and running into big, evil, purple robots named Shockwave.
Perhaps if it got severed at the counterweight's point it couldn't keep up with the rotation of the earth and would simply wrap around the equator two and a half times over the next couple days or weeks?
Oh, it'd be perfectly visible. Yes, the fiber is small, but it will take several billions or trillions of them together to lift anything of any substantial weight. Don't kid yourself, the cable would be several feet in diameter.
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
Consider the ultimate composite nanotube material -- stiffness 10^12 Pascal, yield strength 10^10 Pascal. So at-yield, it stretches 10%. The stored elastic energy density then is 5x10^9 J/m^3. This is roughly the same stored energy as an equal volume of TNT (4.1x10^9 J/ton)! Yikes! You can think of the deployed nanotube bridge as a gigantic PrimaCord detonating system.
No matter how you crunch the numbers, an Earth-based nanotube space bridge has to operate very near to outright chemical instability. Yikes!
Bob Forward had the right idea -- emigrate to a planet with less gravity (like Mars, or the Moon). This makes the whole space bridge idea much more feasible.
Sounds like a juicy target for terrorists.
Engineering problems may go away, but terrorism as a form of warfare may not.
There is another problem that is not being discused. The radiation in the Van Allen belt will affect the carbon nanotubes to the extent that the material would not be usable.
I don't know enough physics and nanotechnology to be sure about this, but I heard about this recently from a high level NASA official. He has brought it up several times and no one has an answer.
A space elevator cannot change the speed of the earth's rotation
And why can't it?
That's right. All your base.
Current proposals for implementation of the Hans Moravec's original design rely on a hypersonic air-breather of advanced aerodynamic design like the Boeing DF-9 (that exists only on paper).
Can /. readers think of 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 bureaucrats 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 -- 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.
Seastead this.
That's why you take it higher than 200 miles, drop it into an eliptical orbit, then correct the orbit with a couple cheap engine burns (very very cheap relative to an all out launch).
It's simple really. As the elevator starts to lean (the beginning of the so-called wrap around), the cable it no longer perpendicular with the ground. If it's not perpendicular to the ground, there will be a tangental force on the ground slowing the earth (immeasurable ammount) and likewise the opposite force on the counterweight speeding up its orbit, correcting the lean.
In reality, you don't get a wrap around, you get a giant pendulum, which is easily corrected. A launch when the pendulum is still or swinging opposite earth's rotation will increase the magnitude of the pendulum swing. A launch that happens when the pendulum is swinging the same direction as earth's rotation will steal energy away from the swing and lower the magnitude of the pendulum swing.
So Fat Bastard should be getting the call any day now?
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
Why does the Tacoma Narrows Bridge come to mind when considering this "space bridge"? If just one complex force we do not yet understand takes place on this "space bridge" could the results be disasterous? The ribbon would have to be about 22,240 miles long and if that structure got torn to shreads and fell to earth, what would the effects be? Has anyone addressed this question? Would it create clouds of nano tube dust particles we could all inhale? Could parts of this structure fall on populated areas (I believe pretty much half the globe lies within the falling radius of such long structure)?
Hey I'm excited about this stuff, but an engineering project needs to be considered from more than just the successful angle.
What are the potential risks?
Authority questions you. Return the favor.
Elevator? Bah! Think of the workout you'd get taking the stairs.
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
If I recall correctly, in the introduction or possibly the afterward of The Fountains of Paradise (at least in this edition), Clarke does indeed mention he was not the original idea man behind the space elevator, and goes on to give praise to Yuri Artsutanov.
The Wikipedia entry for "space elevator" mentions, though, that idea was first proposed by another Russian, Konstantin Tsiolkovsky, in 1895(!).
And finally, for those of you who might be interested, this month's Discover magazine has an all-to-brief article on the space elevator. However, being Discover, it is a bit of a fluff piece, but decent nonetheless.
"Yeah, well, Dracula called and he's coming over tonight for you and I said okay."
Elevator 2010, a challenge for a 250 kg climber to climb a 16 km tether
The first time I read that I pictured a 250 kg PERSON in climbing gear. Followed quickly by "Why don't they just use a 250kg mach... Oh"
Conferences like these always give me a lift.
I wish I had modpoints. Rotovators are indeed much more practical than space elevators. They do not require exotic new materials such as carbon nanotubes. They can be built with cheap materials like spectra or zylon fiber. They are also much shorter (100km instead of 36000km) and more flexible.
This system could double the payload capacity of launchers to geosynchronous transfer orbit or pick up small payloads from suborbital trajectories.
This could be built today. Rotovators are also a very good addition to suborbital space transports such as SpaceShipOne.
Private property is the central institution of a free society (David Friedman)
"Elevator 2010, a challenge for a 250 kg climber to climb a 16 km tether"
How about something possibly a bit more realistic, like a 250kg climber climbing a 50 meter tether.
The problem that I have with the space elevator fanatics is that they are setting goals well in advance of the science and engineering which usually leads to disillusionment and could scare away investors in what is a promising area of development. Carbon nanotubules hold great promise, but it is still just promise until they can be manufactured in suffient lengths and with sufficient ease to be practical for any use let alone a space elevator.
If carbon nanotubules are going to be useful, we will see them used as building materials for much smallers things first. Perhaps as robotic tendons, or longer bridge spans, weaved into lighter armor for vehicles... I could think of many important applications which could use shorter easier to make lengths of nanotubules and would provide the neccessary experience to determine if a space elevator might be practical.
Sometimes small steps are big.
Yes! The sub-orbital anvil launcher from X-Industries will be a reality!
The rule probably refers to the fact that the rope has to support its own weight in addition to the mass you're hanging. The longer the rope, the more of its own weight has to be supported.
An equally valid concern to the weight of the longer piece of rope is that any given rope will have some distribution of strengths on a given length, with deviations.
Thus, a 100 ft length of rope will more likely contain a weaker section (as well as stronger sections, but those won't matter since the break will occur at the weakest section) than will a 1 ft length of rope.
A similar argument applies to the distribution of people controlling nuclear weapons!
The larger the number, the more likely that one of them will be sufficiently crazy to actually push the button and make the whole structure collapse.
BTW, you don't want to be anywhere near a tense rope, steel cable, or chain. When it fails, the remaining pieces can whip around at speeds that will cause mortal damage.
"Provided by the management for your protection."
That's a safety feature... if it breaks all the nanotubes turn to soot in a pretty firework show instead of wrapping the planet up like a Christmas present! Pity about the people on board, though.
This is the third or fourth post with someone bitching b/c someone else asked a question or raised a point. Get a life dude. -ron
I can not believe this is getting so much serious interest by people. And some of the dollar figures being discussed for researching this topic make me want to puke.
Carbon likes extra electrons, and the beanstalk would reach up through and beyond the Van Allen belts. We already know that thunderstorms interact with the ionosphere via `sprites' and other curiously named electrical discharges.
What happens when you run a conductive cable through the ionosphere and up into the van Allen belts?
That's no small potatoes, for ultraprecision wonks.
Put another way, if you launched a billion tons a year you would have about half of the effect on Earth's rotation as the Moon's measured tidal drag over the last 30 years.
Not to knock you off your "Christian mythology" highhorse but since the Tower of Babel story is in Genesis, it's from the Torah and technically rooted in "Jewish Mythology".
Unfortunately, while it's fashionable to throw around terms like "Christian mythology", calling a Jewish story made up will probably just get you labeled as an anti-Semite. Too bad anti-Christian statements aren't treated with the same revulsion as saying Hindus, Jews, Muslims and Buddhists are all living in a fairy tale.
Blaze a trail to the New World
The strongest real carbon-nanotube rope is 1 GPa. Edwards elevator design needs 100 GPa ropes. In Edwards book, "Space Elevators", page 26 he predicted that we would have 100 GPa ropes by 2005 or earlier. We just are not close to this and not moving fast. Last year the record was also 1 GPa.
Now Edwards is predicting another 2 years. He will be wrong again. We had "graphite whiskers" 48 years ago that had 20 GPa and we can not make strong ropes of these yet. These are easier to bind to than nanotubes. So 2 years is just much too optimistic for 100 GPa.
Rockets are so tremendously inefficient because they need to lift all their fuel with themselves. Something like 20% of the space shuttle's fuel is needed just to lift the other 80% of the fuel above the 500-foot altitude of the launching tower. Then you have to spend a good chunk of the remaining fuel just to raise the rest of the fuel up another 500 feet, and so on. It's geometrically inefficient.
With an elevator, as you describe, energy has to be applied both to raise the load's altitude and to get it up to orbital speed. This isn't a trivial problem, but it's solvable with far less overall energy expenditure than rocket fuel. In principle, electric motors can do the lifting work. It's far easier to lift electricity slong a wire to orbital altitudes than to lift rocket reaction mass.
Here's the most relevant quote. .
I remember reading about the Shuttle experiment with the tether, the idea, if I recall, was to see if usable energy could be generated in this manner. Everybody was surprised at how quickly a charge built up and burned out the cable. This doesn't sound good for space elevators!
Any takers on this item?
-FL
However, if you take the train, you go from downtown london to downtown paris. If you're on one of the French high-speed trains, the trip is only about an hour longer than it is by air. Factor in the fact that you can clear customs on the train rather than on the ground after you land, as well as the hour+ drives/cab rides to and from heathrow and charles de gaulle airports, and the train is actually faster for buisiness commuters by at least an hour. Now, there's not many people whose time is worth 149 - 64 = 80 GBP/hour, but they do exist.
There's other reasons, mostly regarding how train travel is generally more pleasant than air travel, and then theres the fact that you can bring your car across to calais from britain, but I found the revelation that the train can be faster door-to-door to be particularly insightful.
">>If we suddenly have 100 miles of superstrong material slamming down at hypersonic speed, it's going to be extremely bad"
That's funny. The proposed space elevator (which uses a paperthin ribbon cable, by the way) has only a tiny fraction of the mass of a single WTC tower.
Something like only 24 tons of material is needed for the initial anchor cable. That's something you can loft aboard in just a few rockets. What's that, one truckload of wound-up starter material that's over 60,000 kilometers long? That's it. Then after that, it's only a few truckloads more of ribbon material, and you're done. The WTC took over 1000 truckloads, the space elevator is far less material.
Space elevator ribbon - It's low density material. Superstrong yes but flexible. Drop a Mylar anti-static plastic bag (for a PC motherboard). That's 1 square feet of elevator ribbon fluttering to the ground pretty harmlessly. The space elevator ribbon will be of much tougher material. However, the space elevator ribbon is actually lighter than that mylar bag!
When a space elevator collapses (which will inevitably happen to at least one space elevator, once they start sprouting up, Murphy's Law is going to always be with us), it'll just mostly flutter down. The stuff in the vaccuum will burn up quickly as they accelerate without friction and hit the atmosphere. Now, the concern is mainly with the lower (atmospheric) portion. Some damage may occur to the platform, and a boat might be capsized if the kickback of the gigantic-rubbery-like "snap" of the most earthmost (lower 10km or so) of cable, hits nearby water with enough force to capsize a small ship. Even so, that may not even happen, because even 100 feet of atmosphere will slow down an ultralight paper-thin material very quickly from supersonic speeds to subsonic speeds. So because of this, ships and platforms are probably going to be very rarely damaged from a falling elevator ribbon! It's not going to be Apocalypse. A falling Lifter will be far more deadly - but far less dangerous than a falling space station or nuclear powered satellite. People are just going to keep reattempting the space elevator, especially if there are successful attempts. The Write Brothers versions of the first few space elevators will definitely have the equivalent of a few biplane crashlandings, a few Apollo 1's and 13's are definitely going to happen, but your scenario is a joke.
Did you read the whole page. At the bottom he says...
We would be far better off to invest the money into more advanced propulsion systems, like those aboard the non-existent (?) TR3 black triangle. Its time this drive technology was released to the masses that paid for it in the first place ! Such propulsion systems won't just get us 62,000 miles from earth, but instead to other planets.
If the government had a propulsion system like that they would use it for space launches.
Anyway the study I read said it would de-ionize an area a few centimeters around the cable, because air is not that conductive, and the Ionosphere regenerates itself.
How about spiders and/or & spider web instead of an elevator?
Break a part of the thread, spider has some kind of safety mechagnism. Thread has some kind of safety mechagnism.
Everything is real cheap on it, but as a whole, it works well together.
-Dean Michael Gores
the lifter may potentially survive as well, i would imagine it would be possibly to find some way to attach a parachute or some other safety device to the lifter and have it detach from the ribbon. even the ribbon above the lifter would probably act somewhat like a parachute for it, slowing its decent.
being in the lifter when the ribbon fails would probably be a survivable event in most cases.
Harsh? Yeah.
Effective? No.
Mind telling me how that stops a terrorist intending to ignite an all-out war between the western world and the Islamic world?
And how are you going to convince anyone that you're serious? Coz just sayin' so ain't gonna cut it. Talk's cheap.
--
If the road to hell is paved with good intentions, where does the road paved with evil intentions lead to?
Sorry, but thermodynamically rockets are among the most efficient machines around. They are very good at converting chemical energy to thrust.
;-) to put the pad on and save all that fuel...)
The thing is, they have to take their reaction mass with them.
With an elevator, the elevator cables (and counterweight) are the reaction mass. Don't forget to calculate the energy and fuel required to build/deploy the elevator in the first place. Sure, because it stays there (instead of dissipating like rocket exhaust) it will, with enough use, eventually be far more effective than a rocket.
(Oh, and about that shuttle fuel thing -- that first 20% isn't just to lift the rest of it to 500 feet, it's also to accelerate it to whatever speed it's going at that point (100 mph or so upwards). Otherwise they could just build a 500 foot hill (biggest in Florida
-- Alastair
Would there be enough energy available to power the climber, for even part of the way?
How would you work this out? Is it (watts to power climber) vs (amount of power that can be dissipated through the cable). Would this be viable?
Thanks
Interesting point.
People usually talk about space elevators as purely static structures. Dynamic ones could be built with current technology, since they don't need any super-strong unobtanium to work. Dynamic elevators scare people, though, because it's easy to see where the energy is stored and what the failure modes might be. But apparently the static designs aren't immune to this sort of problem either. I'd never really considered the static designs in this light. Thanks.
I took mechanical drawing during high school summer school, the drafting teacher got to control the radio, his preference was for the "easy listening" station, it was the early 70's, and lets just say whenever I hear "Just like me, they want to be, close to you. Woohoouhhoo, close to you!" all I can think of is 4H and HB leads. It is strictly Pavlovian.
"Say, can you hit #4,427,615 for me? Thanks!"
JET Program: see Japan, meet intere
And just having a look at the modding that's going on, at least one believer in the God that condemns babies to Hell because they died too quickly has mod points. I'm looking forward to metamodding tomorrow. Oh well, suffering is supposed to be good for the soul, or something like that.
BRACE YOURSELF EVERYONE, WE ARE ALL GOING TO DIE!!! THIS IS ONE EVIL PLOT BY THE TERRORISTS. IF NOT, BETTER MAKE THAT A VERY SECURE SITE.
:)
The earth will go out of it's orbit or worst...wait that's the worst.
You FAT ppl all can take that elevator up to heaven, but I'll take the stairs.
It's just me being on my stressful day.
English is not my native language and there is ALWAYS a counter weight at end of teather in space in full scale. Uhh balloon creating the upperward force for keeping the teather up. I wasn't joking, only my expression wans't best possible.
Emacs is good operating system, but it has one flaw: Its text editor could be better.
Skyhooks are attached to aircraft, not the equator.
Details here.
It's never too late to have a happy childhood.
> Not stupid, but boring. It just doesn't feel like bona fide space travel to me.
That's the idea. A lot of us *want* space travel to become boring.
It's "exciting" that in 43 years since Gagarin, fewer than 500 human beings have been to LEO or above.
It's "exciting" that we're so thrilled to see Spaceship One do what X-15s were doing 45 years ago (albeit more elegantly, with private money).
It's "exciting" that a Shuttle launch costs $350M-$500M instead of the $10M-$20M hoped for in the 1970s.
Enough excitement, OK?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Why not call it a "spacelator"? And make the tubing hollow, get it strung up first, then pump it full of something that will quick harden. If fact, you could erect a giant scaffold that way while we're at it. Of course the stuff would start hardening long before it reached 100 miles so maybe it would have to be distributed along the inside of the tubes and the active ingredient squirted in later as a fast moving gas. As long as you guys keep hitting my website and learning about my engine made of gold you can do what you want with scaffolds. I'm afraid of heights so I'll never use the spacelator anyhow. I sure hope we can get away of using freight-sized elevators for lifting a single human tho. No, I'm wrong again. Given the overall height it would be best to move the scaffolding up in sections, squirt the agent, section again, squirt the agent again. I sure hope somebody has a design for a robot builder that doesn't care about heights or need to breathe oxygen. And doesn't mind squirting agents.
If you build one, you can call it whatever the hell you want to. Until then, it's all wanking. (that means masturbation.)
Why yes, I AM a rocket scientist!
Well lets make SIMPLIFIED calculations... Assume a cubic with 100meter edge. That has volume of million m^3 the air density at target altitude is 1/5kg-0.1 per m^3 [It wasn't clearest graph where I looked the value] Then that sized of ballon can handle 100-200Tons now. Then there is need to stabilize the location of said balloon, in order to test teather. And for that it needs some sort of engine to stay still and the jet engine is not correct choise [ARGH I should of slept more.] But still I think the engine and balloon and fuel will weight a LOT less than the 150Tons assumed lift at the height. Perhaps leaving couple of tons for the weight of teather and 250kg for weight of the climber. Besides balloon made of nanotubes would weight a LOT less than that and the engine and propellers don't weight too much either, nor does the fuel to keep it steady. The height where air is too thin for ANY kind of balloon is over 20 and probably over 30km . And with some nanomaterials there maybe possibility to build even HIGHER climbing balloons.
Emacs is good operating system, but it has one flaw: Its text editor could be better.