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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."
This page seems to have some good links. Just check out the bottom of the page as it indicates if you're new to the idea of space elevators.
Wikipedia have a very good article on space elevators
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?
Christ, why does everything we ever dream of nowadays have to consider terrorism as an influencing factor? What is this obsession with living in fear all the time? Have we been so indoctrinated that we now automatically think in these terms? I say screw the "terrorists" whoever they may be. Perhaps if we spent more time dreaming and less time trying to fight fear with fists we'd be a lot better off anyways...
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."
Well, actually, a little further out than GEO, so that the center of mass is at GEO.
As for wind -- well, you situate it where the wind is minimal. Remember, since it's synched, it's not generating "wind" by slicing through the air. All you'd have to worry about is the wind that is actually blowing past the (stationary) Earth.
The Mongrel Dogs Who Teach
The Spaceward Foundation is creating the Elevator:2010 program:
If we suddenly have 100 miles of superstrong material slamming down at hypersonic speed, it's going to be extremely bad
It'll be more like a 100-mile piece of paper fluttering to the ground. The ribbon will be extremely light. It needs to be, or it can't hold up its own weight. Why don't you go read the Space Elevator FAQ before displaying your ignorance?
Any sufficiently advanced libertarian utopia is indistinguishable from government.
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.
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.
And don't forget it'd be a tremendous icon of Western achievement. You'd better believe everyone in the US, or whatever country eventually builds one, would be proud as hell of it. The media would be going on and on about how it'll usher in a new age for mankind, and so on, and so forth. If terrorists could somehow take it out, wouldn't that have tremendous psychological value? Remember that they chose the World Trade Center and Pentagon to strike at us, two (or three) buildings that symbolized, to them, everything that's wrong with the US. Wouldn't a tower that reaches into the heavens (hello, Tower of Babel?) symbolize that even more?
It's quite reasonable to take terrorism into consideration when designing a structure. As long as you don't let it make the decision for you. Saying "We'll increase the no-fly zone from five miles to twenty five to give us time to shoot down hijacked planes" is good planning. Saying "We just can't eliminate the possibility of terrorism, let's just not build a space elevator" is not.
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?
you're forgetting the big upside of the space elevator: the owners of the space elevator can drop shit on you from space! heavy things like big rocks, kitchen sinks, and 2000 pound gps-guided bombs. and let it be clear, there is no defence against kitchen sinks falling on you from space. we're talking afforable space based weapons platforms. the weapon of choice of the future may be raindrop-shaped ceramic projectiles with spent-uranium cores, raining unstoppably from above and smashing their way through tanks and into underground bunkers, or sinking an aircraft carrier battlegroup.
the military of the country that builds this wonderous weapons platform will let see to the safety of the tether, you can bet on that.
It is not necessary to use a heavy mass at geosynchronous orbet. Instead, make the cable twice as long, and put the center of mass OF THE CABLE at geosynchronous orbit. That way you get extra-orbital launching basically for free.
Did you mount a military-grade, variable-focus MASER on an unlicensed artificial intelligence?
Offtopic:
Remember The Oklahoma Bomb?
Who are "us"?
Who are "them"?
I'm from Argentina: Tango, Asado, Mate, Gaucho, Maradona, YPF
Actually, it wasn't. My first thought was, "cool", but hey...
What really irritates me is that this fear of terrorism is so unreasonable. It's almost akin to the "Won't someone think of the children scenario". The US has been the target of relatively few domestic attacks and of those, one was carried out by a US citizen. Despite this, the fear of terrorism has pervaded the national consciousness so fundamentally that any discussion is now subject to these apocalyptic "what if?" scenarios.
Yes it would be a very bad thing (tm) if someone crashed an airliner into a space elevator, but when that progresses from being a notable, if incredibly unlikely concern, to a point where such fear of the irrational drives society itself, then who cares what the "terrorists" do, they've already won. Of course we should build with the lunatic with a cause in mind, but build we must. This realisation is slowly being eroded. There is a phoenix risen from the ashes of 9/11 filled with hatred and fear, and it is a frightening beast indeed.
Europe has had to live with this for far longer than the US, yet they live in a far freer, far more secure environment than we could ever hope to have. I re-iterate, screw the terrorists. It's the only way we all win.
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.
Don't forget the really big rocket you need to attach to the kitchen sink in order to kill nearly all of its momentum so it doesn't just sit there in orbit with you making you look really foolish.
Nothing.
It's a ribbon. It's literally nearly equal to the weight of an equal width of Saran Wrap.
How much unrolled saran wrap do you have to drop on someone before it hurts them?
How many buildings will be devastated by having something that flimsy dropped on them?
The devastating space elevator fall is bad science fiction. If it breaks, stuff above will stay in orbit, and stuff below the break will fall harmlessly.