Slashdot Mirror
Carefully Timed Jerks Could Power Space Elevator
Hugh Pickens writes "BBC has an interesting article on the long-standing issue of how to power the 'climber' that would ascend a space elevator into space. Previous ideas have included delivering microwave or laser power to the climber beamed from the Earth's surface, but now European Space Agency ground station engineer Age-Raymond Riise has demonstrated a device that could provide a "lift into space" for cheaper space missions along a 100,000-km long tether anchored to the Earth. Riise demonstrated sending power mechanically by providing carefully timed jerks of the cable at its base with a broomstick to represent the cable held in tension, an electric sander to provide a rhythmic vibration to the bottom of the stick, and three brushes representing the climber with their bristles pointing downwards allowing the climber assembly to slide upward along the broomstick as it moved slightly downward, but grip it as it moved slightly upward. 'It would be possible to make a suspension system that completely decouples the cabin where the passengers are,' says Riise. 'For them it would be a linear movement with very little disturbance.' Riise says that he has been approached by commercial elevator companies, who are researching new ideas for elevators in superscrapers where the simplicity of the approach makes it attractive when compared to other ideas for powering lifts, such as compressed air."
Something tells me the average slashdotter might be able to offer assistance in this "scientific research"
...can be used to power the space kleenex dispenser.
Too...many...jokes... [head explodes]
EVER is a long time.
The Space Elevator is something an advanced civilization with a few hours to kill might whip up.
How we know is more important than what we know.
Yeah? Well the jerk store called and they're running out of you!
Y'know, this just might work, seeing that there is such a plentiful supply of jerks on the planet.
What's the difference? You're their all-time best seller.
per dolorem ad astra
Slashdot: Setup lines for bad jokes. Stuff that splatters.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
With criticism like this, I would say this idea is destined to succeed.
"Why is everyone so obsessed with this terrible idea? Even if we got it to work, there's no way we'd be able to afford the maintenance and energy costs. It just isn't viable."
This guy just copied and pasted his post. I found this same post about plane flight, the space shuttle, the hubble, the mars rover, and the lightbulb.
ok, i lied, but you get the point :)
There's nothing Intelligent about Intelligent Design.
Suppose that the elevator's cables are in a ring formation, does that mean we'll have a circle jerk?
Consider how much energy it would take to move this massively long cable. There is no way in hell that is going to be efficient. You're going to be wasting a massive amount of energy as you move the entire cable the whole time the thing is climbing.
To the naive this approach seems workable because it looks simple. The fact is that it takes a certain amount of energy to do things and this is probably a very poor method that will become quite obvious at the scale we are talking about. In this house we obey the laws of thermodynamics and all that...
Then you have to consider the wear and tear on the mechanical parts, especially that really expensive long cable into space. This just seems like a bad idea all around.
The ratio of people to cake is too big
although i like the beauty of it's simplicity, wasn't vibration in the tether already a problem?
it's like a 300 mile long guitar string with a slide going up and down.
one of these days we'll have a /. story about the music of the space elevator.
Yeah? Well, I had sex with your wife!
This is not flamebait - its a classic seinfeld episode: Synopsis full episode.
The jerk store called. They want the third derivative of the position function back.
Oh, yeah, it's not easy to pad these out to 120 characters.
His wife's in a coma...
That would take a while to get up. Then again, with enough jerking I'm sure anything is possibly.
So if I'm reading the title correctly, Lawyers with rolexes could get us into space?
Are those crickets?
Jerking at the base is ok, but jerking at the top works much better.
(mumbles to self) Well the life support machine called... Wait! Thats it! You just screwed yourself Riley!
Jerks.
After all, he is a jerk with an impeccable sense of timing.
an advanced civilization with a few hours to kill
There isn't any evidence that such things exist, of course... :-) "Advanced civilizations," that is.
Mom: "Hello"
Me: "Mom, uh mom, I know it is late but.."
Mom: "Oh hi honey..."
Me: "Hey Mom, do you remember those sincere times when you tearfully told me to quit playing with myself and stop using so much water back in the day and how no good would come of it?"
Mom: "Honey.. It was in your best interest..."
Pause for dramatic effect, a little static on the line, the sound of dad snoring and breathing heavy..
Me: "Mom, NASA just called. They need an expert. I am going to space Momma!..."
Mom: "Oh Darling! I never knew you would succeed like this.. Your father will be so proud! What...what time is it? 2 o'clock?">BR> *rustling covers* *wierd pause* Space? I thought you were happy bagging groceries...
Me: "Well they needed an expert. That's what us experts do. I just got a call on the emergency line. I am gonna have step up training, and need to get started. Tell Dad I love him Mah. Tell dad I love him. If I don't make it.. you can have the cats..."
Mom:" What will you be doing again?"
Is this thing on? Check. Check.
It's one thing to vibrate a broomstick in that manner, and quite another to do so with a 36,000 km space elevator. No matter what material you're using, you're looking at a very large mass; wikipedia estimates "a minimal, very low payload space elevator 'seed ribbon' could have a mass of at least 18,000 kg." -- or just shy of 20 tons. For hauling passengers and goods, you'll need much more. Now, we're talking about accelerating and decelerating this mass of at least 20 tons multiple times per second.
Think about that. We're talking bringing something the weight of a big-rig, accelerating it to a decent speed, and then bringing it back to a stop in a fraction of a second. That requires incredible force. Now, think about the time it takes to accelerate a big rig to highway speeds, and then bring it to a full stop. Now, remember, that's the *minimum* mass we're dealing with. A full-scale elevator is likely to be quite a bit heavier. For another point of reference, the 250 ton commuter train I ride to work every day, if it applies full breaking force in an emergency situation, takes roughly 2,500 feet to come to a complete stop.
And not only do you have to do that, you have to not shake the thing apart in the process. And on top of that, you have to do that without exerting too much force on your passengers; humans can't handle much more than a few Gs.
The other glaring hole is the brush bristles. It's one thing for a coarse brush to support a few ounces of wood, and quite another for it to support a multi-ton cargo container while undergoing rapid acceleration multiple times per second.
Has anyone done the math necessary to show that this idea can actually scale? Because at first blush, it sounds ridiculous.
please, google "begs the question".
Right away, sir. To whom shall I send the results?
Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
I was talking about us.. in a few thousand years.. hopefully after all the dickwads who think making the earth a utopia is achievable have buggered off.
How we know is more important than what we know.
...from take offs to jerk offs? Evolution!
> Actually, this is something the average person can see at home.
If anyone here had been a kid back in the last century, we could all have shared the memory of kite riders (no, I don't really know what they are called in english). While flying a kite, put a piece of paper on the string, and in a strong wind it will ratchet itself up. You could improve them, of course, one of the favorite mods being a release rod which would release the payload upon reaching the kite. You couldn't lift a lot of weight this way, but strategic stinkbomb bombardment was possible. Yes... Kids these days are sure missing out on a lot of things...
Actually, the elevator works fine from a suspension point of view. You just need a balancing mass past geosync altitude (which could be just more cable with a balancing mass and moving vibration dampers). There are questions about how to deal with tangential Coriolis forces from cars going up the elevator. Maybe you might be able to partially balance it with giving the elevator cars a really big charge and a really good capacitance skin so that electrical force from travelling through the Earth's magnetic field balance out the Coriolis force on average?
Laissez lire, et laissez danser; ces deux amusements ne feront jamais de mal au monde. - Voltaire
C-C-C-C-Combo breaker!
... on the count of THREE! ...
It's worse than that actually. The distance to Geosynch is 36000 km. Moving at a 100 km/h (about 55mph) you'd still be underway for 360 hours. There's no way any climbing-mechanism that depends on mechanical transfer from the ribbon will be able to climb even close to fast enough to make the thing practical.
The demonstration shows a climbrate of around 0.1m/s at which speed it'd reach geosynchornous orbit after about 15 years of climbing. Dumbest idea ever.
That's "First Posters", is it not?
"Speaking the Truth in times of universal deceit is a revolutionary act." -- George Orwell