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Space Elevator Prototype Climbs MIT Building
Jackie O writes "According to an employee blog on the Liftport Group website, their prototype robot for the Space Elevator has just successfully climbed a 260-foot building (in a driving snowstorm, no less) at MIT. Now all they have to get it to do is climb over 60 thousand miles into space, carrying things. Good luck there." Update: 11/17 05:17 GMT by T : Liftport has posted some photos from the ascent, too. Thanks!
I bet Spiderman is just a tad bit jealous...
Are we going to start measuring stuff in MIT building heights now?
The link appears not to take us anywhere useful!
This sounds nice. Also why just a space lift. could it also be used to scale other objects that we may not want to risk human life on?
Now all they have to get it to do is climb over 60 thousand miles into space, carrying things. ...and build the space elevator. Isn't that the real show stopper here...?
I heard the real purpose of the test was to place a police car on the roof.
WTF?
Well, I guess a space elevator could be that tall -- if the earth were spinning at 17,000 miles per hour. Hurricanes would be a bit more exciting though.
60k Miles at 290 feet per what seemed like 10 minutes? Too bad I was never good with math
"Now all they have to get it to do is climb over 60 thousand miles into space, carrying things. Good luck there."
Never underestimate a stubborn genius. Besides, its the journey that holds the juice... imagine what they'd accomplish even getting half way there.
Finaly! I never really believed that man walked on the moon, all a big consipiracy! but now i can sleep safe at night knowin that with this news we have at last won the space race! unluck reds!
http://liftport.com/progress/index.php?blog=9&cat= 28
They'll need a tall building...
Analogies don't equal equalities, they are merely somewhat analogous.
Lifter Success!
Woohoo! I have to say that the creator of our robotic lifter, David Shoemaker, rocks! The latest incarnation of the lifter faced what was probably its most difficult challenge to date: climb MIT's 290-foot-tall Green building in the middle of driving snow. And the robot succeeded marvelously, despite some problems!
The morning started off cool, but with temperatures dropping. Blaise Gassend and I brought everything for the rooftop anchor station up to the roof and got it assembled. There was a bit of ice rain that started falling (and melting once it landed), but it wasn't too bad. Once the anchor station was assembled, we headed back inside to finish prepping the ribbon and to work on insulating the lifter's battery. When we went back outside, the weather had changed - it was now a very serious snow storm! I decided that we could go ahead with the lifter test, since the wind wasn't too bad, and I thought that snow was at least better than rain.
We had planned on attaching a safety line to the robot to catch it in case the ribbon broke (which we weren't expecting, but we wanted to be extra cautious). Unfortunately, the safety line was a last minuted addition that did not get tested in advance, and of course it was the thing that broke. Partway up the ribbon, the string that was hooked to the safety rope got tangled in the axle of the lifter, and the rope itself was separated from the string. So our safety line turned out to be more of a detriment than a help! And due to the wind, the ribbon got twisted around perhaps 10 whole revolutions, which also slowed the lifter's ascent. But the lifter kept going, and even though it was slower than normal, it made it all the way up to the roof level, reversed course and headed back down (halfway up, the twist in the ribbon unwound itself).
I want to thank Blaise Gassend for his great help in setting things up and preparing part of the ribbon. Look for pictures and perhaps video to be online within the next few days, and perhaps a more detailed description of the event.!
If robots are now scaling our buildings, we should all be able to sleep a little sounder these days, eh? Boy howdy if there was a robot scaling my house every night I know that no young hooligans would mess with my place.
http://www.purevolume.com/nescienceredemption
Sam
if those MIT kids can measure a bridge in Smoots (Smoot was a student), they can measure make the Green building a larger unit..... try and stop em....
How tall is that... in Smoots?
WikiPedia entry on the Smoot, if you have no clue what I am talking about.
Two Roommates and a Boyfriend, updates Monday, Wednesday, and Friday
Wayne: "from this height.....you could really hock a lugie on someone."
Obama is a twitter sock puppet
As cool as this idea is, there are some problems (especially for the lower altitudes). Some of the problems are more serious than others:
Wind shear: winds at various altitudes can differ widely. Both the cable and anything climbing it will be affected.
Resonance: a cable will tend to vibrate; it will be necessary to dampen the vibration. Usually this is done with strategically placed weights. With an object climbing the cable, however, the resonance will be constantly changing.
No Adspace: There will be no place to put banner ads, so the thing will never be profitable.
Environmentally Harmful: birds could run into it and die. Doesn't anyone consider birds?
sigs, as if you care.
Steve jobs invented the MIT building, and the space elevator.
Too much space junk in low orbit, a collision would be inevitable with a stationary Space Elevator shearing it off and sending it crashing back to Earth.
In all practicality, Space Elevators will never be feasible.
... or about 350 thousand feet.
/me hands Slashdot a lesson on Permalinks
Karma: It's all a bunch of tree-huggin' hippy crap!
I can't help but think about all the political hurdles that'll delay the space elevator more than any technical setbacks. And then I get to thinking about how slow and unromantic a space elevator ascent would be compared to the exciting phallic-rocket launch. Still, the space elevator is about the only way to eventually get launch costs below a dollar per pound; chemical rockets are too energy-wasteful to ever reach that point.
--
Power to the Peaceful
then try this link for those of you who don't know what a "space elevator" is (and insist on hanging around here). It is a faq on a study done on the concept. More info is also on the site.
For Pete's sake... I'm going to get real mad if the guys on the 19th floor keep misusing our R&D technology just to fetch their morning "coffee and donuts"...
The friendliest digital photography forums on the net!
I find it amusing that they're based in Bremerton, WA, which is about the least high-tech place I can imagine.
It's a good idea in theory, but there's the small problem of someone has to go to the top of the building/object to anchor the ribbon in the first place. So once they work around that, it should be fine.
And the fact that a rope and pully would do the same job faster just occured to me.
I don't know if it is even a good idea in theory. Velocity differences and rotations between the two anchoring points would need to be considered. Even if one was going to try to use a geostationary satellite as one end-point, the mass of the object (rope or ribbon,) connecting the satellite to the earth would be significant, and would drag the satellite crashing back down to the earth. If the satellite was on station further out than the geostationary orbit, and the combined center of mass and the rope/ribbon were at the altitude for a geostationary orbit, the stresses involved would be tremendous, especially when the location of the space elevator would vary, causing the center of mass to vary.
Of course, I'm sure those guys at MIT have already done the calculus to figure those things out, and know how much stress would be present.
Just think - a new #1 target for terrorists.
MIT building heights, Miles It's all the same to most of the planet. How about KM? or Metres?
You have to go well beyond geosynchronous orbit, which is like 23 thousand miles high. I would have guessed twice that for the counterweight, but maybe even further as they say.
60000 miles = 316,800,000 feet.
316,800,000 feet / 29 feet per minute = 20.77 years
Could one see the top? Or would it "fade" into the sky?
I suggest you read Slashdot
I fail to see how climbing a 290 foot ribbon, on battery power, is even relevant to building a space elevator. It's realy just someone's fun little robotics engineering project. The amount of energy needed to climb all the way to space is so huge that either a highly energy dense storage medium not yet available, wireless power transmission, or transmitting power on the ribbons themselves if that turns out to be possible, are the only viable options to power a space elevator. Other than that, the lifter is a simple engineering project that could be built today.
what sig?
Can't believe parent is getting modded funny. I mean it might be funny if thats how it was posted, but it clearly says 260 feet. I mean COME ON
--- "End Of Line" - MCP
In fact, you'd be hard pressed to find anything more phallic. HA WE GOT THE BIGGEST IN THE SOLAR SYSTEM!! BEAT THAT MARS!!
Or does it mean that it was fairly windy, snowing abit and it totalling a couple of centimeters on the ground and people who had watched to many catastroph-movies lately bandied about in Libraries burning books and being faintly surprised about how little warmth it produced?
"" How about taking the safety labels off everything, and let the stupidity-problem solve itself? """
I can see my house from here!(tm)
No, I don't think Ringworld had space elevators, or even escalators.
Maybe my psychosis is centered around the monomolecular cables used to attach the shade plates (or whatever he called them) together.
sigs, as if you care.
Oh wait yes I am
They're making this sound like it's a step towards achieving their goal, but really what they did today wasn't a stretch of the imagination like the final goal is.
If I claimed that I can jump to the Moon, you'd look at me like I was crazy, because the laws of physics would be completely in opposition to my claim (for example bones would shatter long before you could exert the force to jump even 50 feet). Now if I showed you that I could jump 3 feet, would that really convince you that I'm making progress towards my claim of jumping to the Moon?
To get back to this space elevator idea, climbing 260 feet is no big deal at all using cables that we have today. It's simple work. However, making a cable that is 30,000+ miles and able to support its own weight plus the weight of the payload is impossible with these cables. They'd need a material that doesn't yet exist.
The real hurdle in this project is not making the robot climb the short conventional cables that are readily available, the real hurdle is getting a hold of cables of unbelievable strength made of a substance that doesn't yet exist.
The parent raises a serious criticism.
I agree with it.
I'm not saying a space elevator isn't feasible, but this stunt doesn't demonstrate anything either way.
Hell, people have scaled buildings taller than that, and that doesn't mean they can just climb their way to outer space.
I say to the team that did this, keep trying, and good work with your dreams. But I also say that this doesn't really demonstrate anything in terms of an actual space elevator.
He won't roll too well after that one use...
They just need to put another 1218460.5384615384615384615384615 260 foot buildings on top.
they SEEM to have made a prototype, but have they considered how they're going to get the muzak to be audible once they get into space?
I don't think so.
--Coming up with something clever... please wait...
Why the cables have to be constructed from carbon nanotubes? I know they are strong, but what is the strength exactly needed for? Thanks...
Story link
What?
Just in Case:
Google Cache
60000 miles = 316,800,000 feet.
316,800,000 feet / 29 feet per minute = 20.77 years
And the first automobile didn't break the sound barrier either - though we now have an experimental model that has, and consumer-grade vehicles routinely cruise FAR faster than those early manufacturers considered.
Ditto trains. Ditto planes. Ditto ships.
Also: As you get farther up you can go faster for a given horsepower. Once you cross synchronous orbit (or when you go back down) you GAIN energy from going farther, and the limit (if you don't want to keep it as velocity) is how fast you can store or dump it.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Wow, I wasn't expecting my blog post to get /.'d. I was dead tired from the day of the test, and just wanted to get some info online for anyone who was curious. Sorry for not getting more details or photos up sooner.
BTW, the height of the building our robot climbed is 290 feet, not 260. Not a huge difference, but I wanted to correct the error in the original /. post.
After seeing more than a half-dozen comments on my blog post right after being slashdotted tonight, I got real motivated to get the pictures up ASAP. You can now see pictures of the day at http://www.liftport.com/gallery/MITdemo_2004Nov
A fart in an elevator.
I'm glad I didn't go with 'Able to leap tall buildings...'
Or even 'Wait around for hours, and 2 elevators arrive at once... going the wrong way'
need.... more.... coffee....
This sig is intentionally blank
Wake me when people are tying their shoes with nanotube laces.
I've seen strengths of 65-120 GPa listed for the minimum required strength for a space elevator cable. Spider silk is around 1.3 Gpa, so it's not even close to being as strong as what's needed.
Spider silk is about as strong as Nylon, both of which are many times as strong as steel for the same weight.
"(in a driving snowstorm, no less)", Hmmm, has global warming dumbed down the odd snowflake into a blizzard already.
:D
Somebody who describes a few flakes as a driving snowstorm is hardly going to get me excited about a motor that goes up ropes.
Why not just put a pully at the top and have a bucket at each end. Given the amount of space junk we could just drop it ionto the other bucket and let it pull up the load into space =). Or perhaps wait until the other bucket fills with rain. =).
Seriously, how many lifts you know and trust in this World and they want to string us on the other end. Go back to 1000 atom bombs exploding in sequence underneath a Titanic sized spaceship, I'm sure that idea was more sturdier
I don't know if a butterfly flapping it wings can cause a tornado halfway around the world, but what does a 65,000' structure protruding from our planet's surface out into space do the the universe?
While this was perhaps a decent accomplishment, you shouldn't try to milk it with respect to the weather. While it did snow, it was only barely heavy enough for there to actually be snow the next day, and it was barely below freezing. In fact, the snow was alternating between snow and sleetish rainy cold annoying preccipitation.
:-)
So mad props, but if we were at the same MIT, the weather didn't really figure into the accomplishment
Of course, had there been heavy winds, and there weren't, then you could talk...
Now all they have to get it to do is climb over 60 thousand miles into space
Funny, I thought space was a lot closer than that.
--- Asking inconvenient questions for over 30 years...
Or, slightly more verbosely, we can't build a space elevator because we can't construct a strong enough "ribbon". Carbon nanotubes are theoretically strong enough, but nobody has yet reported a macroscopic piece of material made from them that has the required tensile strength. While there is a lot of nanotube research going on, there's no guarantee that the right materials will be available soon. There's no guarantee that such materials will ever be available.
Don't get me wrong, I sincerely hope that the space elevator can be built. But until I can hold, in my hand, the requisite bit of unobtanium with enough tensile strength, I'll stifle my excitement.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
Mod Down.
The link isn't related to this at all - its to something rather disturbing instead!
Don't get me wrong, a space-elevator would be cool. But what's exciting about this work?
They made a robot climb a 290-foot strap. Big deal. They didn't have to worry about whether the strap would even support it's own weight (when you're talking about 60 miles, that's a tough engineering challenge), they didn't have to worry about the top end coming out of oribtal sync with the first end, they didn't have to worry about lightning strikes, and the list goes on.
Now I'm not just trying to be a jerk here, I just really can't see anything terribly exciting in what they've done.
steve
Oh, you're not stuck, you're just unable to let go of the onion rings.
If the length was longer or shorter, your upper attachment point would move around at a different speed than your lower point (on the surface of Earth, presumably).
Unless you want a mobile lower-attachment (on a big boat, or something), this would probably be a problem. Even if you did have a mobile base station, I have to wonder if it would be possible to keep up -constantly-.
So SpaceShip One is obsolite now?
Why have the last two headlines' from-the-X-dept taglines both featured Hopkins/Lecter? Neither of them are particularly obvious links to the story. Is timothy contemplating cannibalism?
Is it just me, or you guys can hear this too? Jimmy Page, Elevator to Heaven...
2. Prevent damage to the earth end attachment point? Winds, earthquakes, electrical storms, not to mention that it sounds like a terrorist's wet dream to me.
3. Get sane people to ride this contraption, which is effectively the largest slingshot ever if something goes wrong? I mean, hanging your life from a 60k mile long ribbon? What's the backup plan if that thing breaks?
"And now, Frank N. Furter, your time has come. Say 'goodbye' to all of this, and 'hello'... to oblivion!"
Even if all the technical difficulties get solved. I can't see this being built unless it can make money.
My Weblog
Clearly either the person writing this has never been in a driving snowstorm or the winters in Boston are more mild than I thought...you can still see a) the grass b) the cable c) the rail in front of the camera! ;)
It's only driving when the wind is making you lean over 30 degrees and you have to follow the footprints in the snow in front of you to find your way (says the Rochesterian).
Copyright © 1996 by Joshua W. Burton( burton AT het DOT brown DOT edu). All Rights Reserved.
I did a lot of calculations about this a few years back; here are some results that might interest you. Here's the apparent strength of gravity as you go up the elevator, allowing for both the earth's rotation and the 1/r field:
Apparent gravity table 0km 9.8m/s
350km 9.0m/s
700km 8.0m/s
1200km 7.0m/s
1750km 6.0m/s
2500km 5.0m/s
3400km 4.0m/s
7500km 2.0m/s
10500km 1.0m/s
18500km 0.5m/s
Weightlessness comes at the Clarke point, of course, 35950 km up. Above that, there is a centrifugal effect, and the earth appears to be 'above' you---but you would have to be nearly 200,000 km up before the apparent gravity reaches -1.0 m/s. In practice, no one would build it out that far; you just want to go far enough to keep the center of gravity at the Clarke point, plus a bit more to put the lower end of the elevator in tension. A big mass just slightly above synchronous orbit is probably the way to go.
Midway Station, the lowest point where you go into an elliptical orbit instead of hitting the ground if you jump off, is 23450 km up, and has a tiny apparent gravity of 0.29 m/s. The total energy cost from ground to the Clarke point is just over 13 kW-hr per kg lifted, which means $100 a ticket at today's energy prices, minus savings for energy generated by the 'down' cars, plus (rather large) financing charges on the capital investment.
Next come strength-of-materials considerations. We need a material with the highest possible (breaking strength)/(density), which is a tough sell, because Kevlar, good piano wire, and nearly everything else has essentially the same optimum value for this parameter. They all have breaking strengths of a 'few' billion Pa, and a density of a 'few' thousand kg/m, where 'few' is the same number in both cases. The strongest high-tensile materials are the heaviest, by and large. Exotic materials like spun sapphire or diamond do better on the micron scale, and buckytubes get close to the theoretical limit (the strength of the chemical bonds themselves). In principle, such materials should be anywhere from 40 to 120 times stronger than the optimal value above, which I shall call '1x piano wire'. But Griffith theory teaches us that the length of the 'critical' crack (one that releases enough energy to drive its own spontaneous propagation) goes down as 1/(stress). So even if exotic materials can be machined in gigaton lots, we may find that they are unusable at the huge stresses we need. The first woodpecker that comes along may bring the whole thing down if the critical crack is a few microns long.
But let's assume we can cope with this issue, if necessary with nanobot inspectors checking for micro-cracks, or simply a sheath of unstressed material around the structural members. The tension is essentially zero at the bottom: if we wanted we could leave the cable hanging loose a foot from the ground. (We want some tension there, of course, when we build an actual elevator, or the dynamic oscillations will kill us.) At the Clarke point, where the stress is largest, the stress depends on the weight of the tower below, which depends on the strength of the material. It's like rocketry, ironically enough: the 'fuel' for the upper stages is 'payload' cost for the lower ones. In this case, of course, it's upside-down: we have to keep the lower part of the tower as light as we dare, so that the upper part doesn't have to be exponentially heavy. And a high-tensile steel tower, like a rocket powered by Wisconsin butter (happy now, Senator Proxmire?), just doesn't have enough juice.
Assuming each wire has to take a thousand tonnes of tension at the bottom (add wires as needed, depending on what you want to send up the tower...), we get a minimum thickness profile like this:
Minimum thickness table Strength/Density 5000km 10000km Midway Clarke Orbit
6 x piano wire r = 16cm
In the text summary, I was picturing something like this in robotic form, and with this sort of weather. But sadly, I find that the robot was manufactured by an American, rather than a Japanese team, and the weather was an American definition of a blizzard, rather than a Canadian one. :(
Power will be beamed to the lifters by a medium intensity near-infrared laser. It would not be a good idea to stand infront of such a laser, but it won't hurt you to run your hand through it or even to walk (or fly) quickly through it. The lifters will carry an array of photovoltaic cells keyed to the wavelength of the laser, making a surprisingly efficient power transfer. The adaptive optics (for aiming and mitigating atmospheric distortion) and lasers themselves are in the demonstration stages (for other projects).
mspeten@liftport.com
I guess this trumps my "space escalator" idea.
The google cache posted in the parent is bogus. It's a goatse link and actually managed to hang firefox. It wasn't able to render the full image before hanging, but anyhow, this looks like a trend. Fuck off, we don't need people like that here. We'll always have them, but fuck off anyway.
All the tech was in the robot, not the ribbon - and frankly it does not sound so easy to me to design a robot meant to carry weight up a twisting ribbon.
Sure there are a lot of challenges for a space elevator. But don't throw cold water on first inital steps, even if it's the lifter tech and not the ribbon itself.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Bruce
Bruce Perens.
Thank you your massive overdoes of attention. As of right now the server seems to have melted into a puddle of slag in the data center. Our provider is, I'm sure, overjoyed at the attention. Nothing like being /.d to make a night more enjoyable.
Not that I'm complaining, exactly. But damn, could you guys have been a little more gentle?
Display some adaptability.
So, it has a energy-storage and a climbing-mechanism, none of which can climb to space, even with improvements. Instead both components will need to be made fundamentally different.
Most serious designs I've seen use energy from an external source, because if you are carrying your own energy on the climber, then you use most of your power to lift the energy-storage. (sorta like rockets are mostly lifting rocket-fuel) Ideas include powerful lasers shining on the thing from below, being converted to electricity by efficient photocells. (cells tuned to a single frequency like laser can be more efficient than full-spectrum cells) The laser will get weaker as the climber gains heigth, but so will gravity and thus the required energy.
For the actual climbing a non-contact method would be preferable, perhaps something involving magnetism. (essentially a vertical maglev) The trick is to manage that without making the ribbon itself much heavier. (and thus more expensive)
The result will be music that whales everywhere can enjoy!
Why exactly do we need a giant elevator into space again? I mean, once you get up there, there isn't a whole lot to see except the view.
Don't take life so seriously. No one makes it out alive.
Elevator from the Earth to the Sun? Where would you anchor the elevator? Both the earth and moon rotate...
Geosychronous orbit occurs wear the speed necessary to maintain that orbit (determined by acceleration towards earth due to gravity) matches the rate at which the planet turns.
Apply more force than gravity (using, say, a carbon nano-tube cable attached to earth) and you can make the cable longer, as the extra force from the cable tension will allow you to accelerate more than gravity alone, and thus allow your object to orbit fast enough at the higher orbits to keep geosynchronous without flying off into space.
paintball
The reds already beat us to it, because IN SOVIET RUSSIA... ...buildings climb space elevators.
paintball
I don't think we need to worry about terrorists until Dubya is here to save mankind. Don't we all know that the world is a safer place to live now because of him and his gang of goons a la Counter Strike?
-- rxMx --
Love all, Trust few, Follow one.
As mentioned in http://www.space.com/businesstechnology/technology /space_elevator_020327-1.html (on page 2) is the probable energy source solar-cells with lasers directed from earth giving it power.
Buy all your crazy japanese videogames from
unromantic???? think again!!! at mach speed 1.0 you could take 24 hours to reach 30.000 miles altitude to inspect the space anchor. imagine all that time locked with that female russian engineer.... What can wy doo now, my amerrrican comerrrrrade?
I hope the any sky elevators will be more robust than liftports servers :P
I'm just wondering why there is only ever one anchour point? Wouldn't 3-4 make more sense? Once out of the atmoshere they could be joined.. Or even one primary cable with several backups, incase on is severed or damaged and needs repair. It would make re-attaching it a lot eaiser, i'd think?
Just drop (er throw) them down with a parachute. :)
09F91102 no, 455FE104 nope, F190A1E8 uh-uh, 7A5F8A09 that's not it, C87294CE no. Ah! 452F6E403CDF10714E41DFAA257D313F.
None of the links work. In fact, the domain they point to isn't even found. This story must have been a big hoax, was it?
and people think they have the stamina to erect a 60 mile space elevator?
Let's see, we can get to space by punching a hole in the atmosphere at multiples of the speed of sound, but we can't figure out how to do it slowly? That does not pass the smell test. Less energy is wasted by a slower moving object than a fast one. That, and not needing to throw away tons of structures every time you hoist a few pounds, are the whole reason to do this.
A real concern is protecting people against solar flares. At 80,000 feet, you can get up to 10 R / hr. That's not a nice field to hang around in without good shielding.
Every little piece of the puzzle will be solved one little dream and project at a time. You don't learn anything without thinking about the problem and doing things about it.
Friends don't help friends install M$ junk.
100 years from now at the old robots home...
You robots today have it so easy!
Why, back in the day... I had to climb a 260 foot building! Straight Up! In a driving snowstorm!
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
You don't have to climb anything, you just clip the payload onto the rope, cut the anchors, and away she goes. Then once its up there you reel in your line, fly back into orbit, and drop anchor back down to the Earth for another go. Apparently nobody goes fishing around here. Sheesh.
Clickety Click
There is a previous MSNBC story with a picture of the lifter here.
/.'ed but can still be viewed via the google cache here, here, here, and a FAQ here,
The Liftport site was
Today's vices may be tomorrow's virtues.
Yeah, let's see, they built a space elevator, except it doesn't go into space, so really it's just...an elevator? Attached to a building? Is this really news? I've seen elevators attached to buildings before. Not exactly newsworthy.
:)~
Oh, and they built a robot that was able to, um, climb the elevator? Aren't elevators something you ride, not climb? And why would you need a robot to ride an elevator? Wouldn't an ordinary rock do the trick? Is this actually a prototype for a space ladder? If these guys expect me to climb all the way to geo-sync orbit, they can just think again!
Oh well, I'm sure they did something interesting, but I haven't got time to RTFA right now, and the slashdot summary is pretty much information-free, so I guess I'll just have to wait to find out more.
Attention class!
To remove energy from a vibrating structure such that it reduces the amplitude of vibration and distributes energy over the response spectrum is known as damping. NOT dampening. Hence the structure would be damped not dampened.
As a wise man once told me damping is what happens in vibrations, dampening is what a dog does to a fire hydrant.
class dismissed
You look at this like it means nothing... as if these guys are crazy.
I'm sure, 100 some odd years ago, people looked at the Wright brothers like you people are looking upon space elevator enthusiasts.
The Wright brothers first flight lasted, what, less than 30 seconds and less than 500 feet? They were worlds away from it being physically possible for a plane to cross a town, state, country, nevermind an ocean.
But guess what, in 1919, it happened.
I'm also sure that in the early 50's, people thought Science-fiction was an impossibility, no way would people ever put themselves into space. Oh wait... that happened too.
Surely, we could never bring ourselves to the moon, nevermind other planets.
Wait a tic...
hungry~~~ for mirror~~~ neeeeed pictures....*drool*
m y k a r m a i s m o r e p o s i t i v e t h a n y o u r s.
Once the car has finished the ascent out to the waypoint station, it begins a return on that expended energy. Using regenerative breaking on the descent, driven simply by gravity, will economically and safely slow the car (virtual friction as opposed to literal component wear) and store up massive amounts of energy - for local use or transmission, your pick.
Any spoon would be too big.
We could deal with reentry the same way we do now. Alternatively, with an abundance of fuel, you could perhaps descend very differently. First maneuver to a low orbit. Then cancel out your momentum, and drop like rocket guy.
I don't know the numbers involved, so maybe this isn't practical even with a space elevator feeding you everything you need, but it sure would be nice not to have to worry about burning up in the Earth's atmosphere.
Fuck the system? Nah, you might catch something.
- They make a carbon nanotube that's at least a mile long.
- And that can can take 3x the stress required.
- And can withstand a direct hit by a 747.
- And can withstand a typical lightning-bolt.
- And can take a direct hit by a pea-sized piece of orbiting space-junk.
- And you find an insurance company that will write a policy on it. (Both liability and collision).
Until then I'll ust yawn at these semi-weekly pop-ups of this subject.We don't need to defend all of it the same way - damn few te4rrorist organizations have spaceflight capability, so 40,000 ft is a practical upper limit.
Secondly, as others have pointed out, breaking the tether near the ground, while bad for the elevator, has minimal effect on the planet - the section below the break will fall, but that's rather thin. The secion above the break ligts away, due to the counterweight being above geosynch orbit.
Will draw the worlds biggest lightening bolts and create the largest current flow on the planet for a few milliseconds, just prior to melting the nanotubules.
In 1980 (79?) I did a Co-op block at Comsat, the US part of Intelsat, responsible for the first telecommunications satelites. Because these were first described by Arthur Clarke in a science fiction story, he was given the 'first' share of stock in the company and began a long and friendly relationship with the people there. Fast forward to my tenure, where I was working with the 'resident genius' in my department (I don't know what his actual title was, but essentially he had no formal assignments other than to come up with amazing things) using some god-awful quasi-language based on fortran (it was supposed to be really good at matrix calculations and I was writing a program to calculate solar cell array degradation over the life of a satelite. It was my first introduction to dealing with something billed as 'amazing' that almost, but not quite, did what you needed it to do. But I digress from this digression...). I would frequently see him pouring over calculations and eventually asked him what he was doing. "Calculating the tensile strength needed to make a space cable." Then followed a lengthy discussion of what we now call a space elevator. I asked if Comsat was planning to build one. It turns out Arthur Clarke had asked him to do the calculations for a book he was currently writing. I assume his genesis of the idea led to it being called the Clarke point.
I never actually read the book, as, although I always find Clarke's ideas interesting, his writing just grates on my nerves.
FWIW
At time of writing, the site is unreachable so it's time to remember the people at http://mirrordot.org/ who do what /. should have done long ago.
The images are here.
Men are born ignorant, not stupid; they are made stupid by education. Bertrand Russel
The problem is that all the strength needs to be at the top; the bottom end needs to be light because it's effectively being dangled from the top.
I liked how they have a countdown meter that is counting down until 2018, when I assume they believe their first lift will occur. Very funny how precise they are.
Given that all the images in their gallery are of Lego crawlers, I think they have a lot of work to do...
I doubt that Technic Lego's are going to get us into space. Could be wrong tho....
Do it for da shorties
"They key problem these days is in reliably synthesizing significant lengths of nanotube consistently and reliably."
Not to mention doing it reliably.
=)
Making tennis rackets lighter? I agree that's a complete waste of time, as it's for kids and old people. The pros and those who aspire to greatness regularly play with 12+oz rackets, not the 9oz feather ones.
:)
Like I said, a totally anal point. You were warned by the subject
"If you could only see what I've seen with your eyes..." - Roy Batty
...is, one assumes, climbing the Empire State Building. With that, of course, they'd have to life one of those giant inflatable gorillas....
mark "so who plays Fay Wray?"
The cable at ground level needs to be as light as possible to minimize stress at the Clarke point. At the Clarke point, stress is highest, but weight is negligible. Could the problem be solved with a cable that changes its composition? At ground level, the cable would be built from a very light weight material - just strong enough to keep it tethered. At the Clarke point, the cable would be extremely strong - but heavy. Would an optimized tapered cable of this sort do the job without nanotubes?
Cool Pictures. Any close up shots of your robot?
I'd be interested in reading more about your project, is there additional writeups available online or elsewhere?
In the photos it appeared that only the top of the cable was fixed in place. The bottom seemed to be free. Was that the case?
A 2,000 pound satellite travelling at 16,000mph has enough energy to blast an aircraft carrier out of the water. There are hundreds of such satellites in low orbit around the Earth. Eventually one would collide with a space elevator smashing it to pieces.
For this reason alone space elevators will never be feasible!
> So screw colonizing Mars,
;-)
> we need to occupy it now or the terrorists will win.
If we can get the terrorists to go to Mars and try to scare us there, then we'll have them out of our way, so we can build our space elevator in peace.
...the engineering subgroups have invented so much specialized jargon that they can no longer touch bases, forcing the project to be abandoned.
Is it just me, or does this look like they just Jerry-rigged this thing at the last minute? I'm imagining a space elevator held together by 2x4s and water pipes. Hey, I'm all for it if it works!
The cable would "vibrate" because of the wind, but the second concern should be of the electrical energy collected by the cable as the wind passes by it. Some Space shuttle experiments using a cable with a metal sphere tethered on it produced more energy than was expected to. Couldn't this electric byproduct be attached to a power grid and sold to help finance the elevator's payroll?
All the above not-with-standing, a cool thing to see :)
I know this is going off topic, but when folks try to mirror stuff, know the reasons behind it. /. doesn't mirror images and websites mainly for legal reasons, not technical. While some sites would more than likely enjoy having a 3rd party do the mirrors (and this story about the elevator is perhaps one of them), it gets really iffy in a legal sense when you are linking to copyrighted content and you provide a mirror of that content. If another group wants to take that legal risk, /. and OSTG certainly won't be complaining too much. User comments can certainly "spread the word" if you provide such a mirror.
/. has been slashdotted. Most notably during 9/11, and on November 2nd of this year (with all of the election stuff spilling over from the politics subsection). Other similar events overwhelmed not just /. but most internet news websites in general. That is a time you would perhpas NOT want to be a mirror, but that is only a guess.
There are times, BTW, that
"Again with the birds! Birds will fly into just about anything over 5 feet tall - it's called "natural selection"."
And it is PRECISELY this evolutionary pressure that dictates how tall a man may grow.
If one looks back through history one can see from the fossil record that in the past humans were shorter (http://en.wikipedia.org/wiki/Human_height). Also, in the ancient past there was less pollution. These relatively lower levels of pollution in the past are associated with higher bird populations.
Obviously, what is going on here is that as we pollute our environment we are killing off the birds that are the evolutionary check on our hight.
Further, one can see mechanisms to deal with avian-induced pygmy-ism in larger animals on earth. The elephand evolved a larg, strong trunk in order to snatch birds out of the air and protect itself from attack. And who can ever forget the sight of a giraffe, with it's razor reflexes, whipping its head around and eating birds right out of the air? Indeed, giraffes are voracious carnivores, that have evolved great height specifically to present themselves as an obstical to the bird flightpath. These noble beasts are now threatened with extinction as our pollution destroys their food source.
In the future, if we don't reign in our pollution we may destroy our environment. And don't think I'm talking about just basketball hoops. Ceilings and doorways would have to be raised to account for the greater height of our giant species. Lack of birds keeping us short would lead to massive overhauls necessary in many different aspects of our lives, from the lenght of ambulances, to the length of our societies pants (and the speed at which we exhaust our denim reserves in Alaska and the Middle East). So: Give a hoot! Don't pollute.
Adam
Ooooooohhh... impressive! A chassis with tape rollers that climbs up a tape!!! AMAZING
Don't you get that uneasy feeling when you use the word assume?
Konstantin Tsiolkovsky is acknowledged as the creator of the space elevator concept, in 1895. He even had the concept of a station at geosynchronous orbit on the cable, so Sir Clark can't get credit for coming up with either of those concepts. Sir Clark did come up with the idea of putting a radio satellite in geosynchronous orbit though and it is for this idea that the orbit is called the Clark orbit.
http://en.wikipedia.org/wiki/Space_elevator#Histor y
And as you tread the halls of sanity, You feel so glad to be, Unable to go beyond. I have a message, From another time..
The world record length for carbon nanotubes is only about 4 cm. PHDs with big PHD salaries and big lab budgets are spending lots and lots of money trying to make them bigger.
The scientists still don't know whether the nanotubes will remain strong once they get bigger, or whether individual tubes can be "woven" together without losing most of the strength of the tiny little cables.
This research is hard work. Mass producing the carbon nanotubes will also be hard work. Dropping the price per tube by several orders of magnitude will probably be required, even to get down to
a hobbyist level where making a nanotube costs only $1.
Suppose a genie swoops down this morning, and magically enables us to create, assembly, and mass produce nanotubes at a cost of only $1/nanotube, and that these tubes will magially lose no strength in the process.
We'll also say we can make also make our nanotubes 5 cm long, just to make the math easier.
Cost to stitch together a big 2m x 100 km ribbon of the stuff:
5cm * 20 = 1m x 1000 = 1km * 100 = 100 km.
2*10^6 nanotubes long, by
100 nm (say) nanotube = 10^9m/100 * 1000 * 100
= 10 ^ 12 nm wide
by say, 1cm thick (you have to attach things to it, so it needs some thickness on a macro scale).
10^9m/100 = 10^7
We would need: 2*10^6 * 10 ^7 * 10 ^12 nanotubes.
At $1/nanotube (thousands of times cheaper than we can manufacture them today), our materials cost for our elevator is $2*10^23. A few billion (10^9) dollars for the space program seems cheaper now, doesn't it?
--
AC
So the problem of getting into space has been reduced to: Wait until the have a building that reaches orbit, and bingo, this technology gives the US an instant space elevator!
Well, we can start by shaving your back, Svetlana...
the whole Smoots thing is just MIT's way of distracting your attention from the fact that the bridge immediately adjacent to their school is properly called the "Harvard Bridge"
(Peter has kidnapped the Pope, and is driving him across the country.)
Pope: Are you sure this is Boston?
Peter: Sure. Look, there's Harvard. (Points to a pig farm.)
Pope: That's a pig farm.
Peter: Oh, *someone* went to Yale.
This is the interesting picture here. You really don't think those black craters are from previous prototypes, do ya?
STILL WRONG.
Star Wars wasn't good.
Excuse me, but doesn't the space elevator actually 'steal' momentum from the Earth's rotation when bringing mass into the space, which accounts for the huge "energy savings" when using the space elevator vs. a regular rocket? Think about a spinning ballett-dancer who stretches her arms out, and then her rotational speed decreases. Are there some math heads here who can calculate how much mass we can move out how far, before the rotation of the Earth has dropped to a questionable level?
One of the pics. A wonderful reminder of just how ugly MIT is.
Minor point: you implied that gravity was in effect up to 35950 km and that centrifugal effect applied above that. In fact, both forces work on the whole length of the elevator, but gravity decreases and centrifigal force increases as you go up. At 35,950 km they are equal, and above that centrifigal force is larger. Bob Munck (Brown '67)