Slashdot Mirror
Japanese Begin Working On Space Elevator
thebryce writes "From cyborg housemaids and waterpowered cars to dog translators and rocket boots, Japanese boffins have racked up plenty of near-misses in the quest to turn science fiction into reality. Now the finest scientific minds of Japan are devoting themselves to cracking the greatest sci-fi vision of all: the space elevator. Man has so far conquered space by painfully and inefficiently blasting himself out of the atmosphere but the 21st century should bring a more leisurely ride to the final frontier. Japan is increasingly confident that its sprawling academic and industrial base can solve those issues, and has even put the astonishingly low price tag of a trillion yen (£5 billion) on building the elevator. Japan is renowned as a global leader in the precision engineering and high-quality material production without which the idea could never be possible."
Just imagine fourteen hours of Japanese elevator music. I couldn't stand that much symphonic David Hasselhoff. And when you get to space and arrive at the Japanese Sky Deck, you can eat very expensive steak, while being entertained by a Max Headroom stylized recreation of David Hasselhoff, and groped by Hentai-motivated space-whores.
The dangers of knowledge trigger emotional distress in human beings.
$9 Billion Here, $9 Billion there -- pretty soon we'll start talking about real money.
They're going to use Mothra for the lift engine of the elevators.
The simple truth is that interstellar distances will not fit into the human imagination
- Douglas Adams
The concept of a space elevator, of course, requires a very very tall structure, or a pully of sorts from space. That would need to be a really damn strong system, to pull somebody up that high...
Yes, you instantly recognized the challenges of the project. Please, come, be a manager on the project!
Red Leader Standing By!
"The first space elevator will be built about fify years after everyone stops laughing."
-Arthur C. Clarke
The meek may inherit the earth, but the strong shall take the stars.
Nor did you RTFWikipedia. It's a held up by a weight at geosynchronous orbit. The only problem is that geosynchronous orbit is so far out there (the red dotted line is the International Space Station, the black dotted line is GEO), so it requires a WHOLE LOT of exotic material.
Absent any stunning advances in material sciences,
The TFA states that carbon nanotubes would require a 4x increase in strength compared to present-day materials, and that the past 5 years of research have already brought about a 100-fold improvement ... sounds to me like many stunning advances have already happened and we're well on track to fully-stunned status.
This is just a Popular Science article, i.e. "hey wouldn't it be neat if but it ain't happening so we're really just jerking your chain."
"Japan is hosting an international conference in November to draw up a timetable for the machine."
If libertarians are so opposed to effective government, why don't they all move to Somalia?
That's probably not how it would be done. You'd have a ribbon hanging down from geostationary to the equator, and your vehicle would actively climb up it, rather than being hauled up. The ribbon still needs to be incredibly strong and light, but it's not the component that's actually doing the work.
Exercise for the reader: work out how you're going to power the climber.
Real Daleks don't climb stairs - they level the building.
And as a sub-subnote, this is approximately the cost of developing a complete conventional man-rated rocket launch system. I'm skeptical of the quoted price tag, but it would be extremely cheap if it could be achieved.
If you mod me Overrated, you are admitting that you have no penis.
You have an anchor at the top of the ribbon. It needs to be very massive compared to the payload - so we need a large space station, or a small captured asteroid. You have it in an orbit that's slightly above geostationary, so that it tends to drift into a higher orbit and is kept in place by tension in the ribbon. That way, the top is pulling upwards naturally, and the payload doesn't drag the whole structure down.
Real Daleks don't climb stairs - they level the building.
maintaining geosynchronous orbit while tethered to the ground is not a good idea. there are so many factors that could turn a space elevator into a complete disaster. a cat-4 or 5 hurricane could potentially put so much drag onto the cable that the whole thing tumbles to earth. an earthquake could yank it out of orbit. tidal pulls from the moon could rip it from the ground. lightning damage. i'd love to see this become a reality, but i just dont think that will happen.
FOXTROT UNIFORM CHARLIE KILO
A practical space elevator could use vehicles powered by electric motors, which would get about 70-80% efficiency. On the way down, the motors could be used as generators, getting back probably around 30-50% of the original energy supplied. The total energy consumption might only be a percent or so of that needed for a rocket. The design of the cable with electrical conductors on either side reaching all the way up to geostationary orbit is, of course, left as an exercise to the reader.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
Technically, a weight in geosynchronous orbit would remain at the same altitude indefinitely with no other forces in effect. A space elevator will require a weight placed in an orbit which will supply tension — otherwise it'd be pulled out of orbit. It would probably be close to geosynchronous, but not quite.
(Actually, I'm not sure we even have a name for such an orbit. It would have to remain stationary above a point on the earth, but it would also have to hold up the cable and the car – in other words, without the tether it'd fly off into an entirely different orbit. Also, whenever the car accelerates it will put an additional tug on the cable – equal and opposite forces, you know. It'll be a tidy little equilibrium problem, and I'm glad I don't have to solve it!)
Alexander Peter Kristopeit bought his basement from his mommy for one dollar.
Well, no. Modern materials are within a factor of 3 or so of what's required for a space elevator, and known materials with sufficient theoretical strength exist, it just needs to be figured out how to build them. It would not be surprising to have those materials move from theory to reality within a decade or so.
AI, human-indistinguishable androids, and world peace, on the other hand, are not things that people have any idea how to achieve. And FTL drives are prohibited by currently accepted physical theory. To compare a space elevator to any of those is either deliberately being stupid, or a result of profound ignorance about either space elevators or all the other things you mentioned.
A space elevator is certainly not going to be as easy as a Popular Science article makes it sound. But on the other hand it's not anywhere near as difficult as the pipe dreams you named.
If you mod me Overrated, you are admitting that you have no penis.
...No space elevator is going anywhere without the necessary nanotube manufacturing breakthrough, and that includes the Japanese.
Exercise for the reader: work out how you're going to power the climber.
CowboyNeal as a counterweight?
Technically, a weight in geosynchronous orbit would remain at the same altitude indefinitely with no other forces in effect. A space elevator will require a weight placed in an orbit which will supply tension â" otherwise it'd be pulled out of orbit. It would probably be close to geosynchronous, but not quite.
Couldn' this be achieved by moving a counter-weight downwards from space while the elevator moves up?
The total force on the weight in orbit would remain constant wouldn't it?
They just saw that the EU completed the LHC world wonder so they are building a Space Elevator wonder to prevent a cultural victory.
I'm always afraid of getting stuck halfway up on a space elevator (one bustle in your hedgerow and the whole thing gets jammed up). I'll just take a Stairway to Heaven, there's a lady I've heard good things about that is buying one.
I thought a millionfold increase in length was also required?
Does not matter how strong they are if you cannot make them long enough.
would that work to finance the japanes space elevator:
1- take a subprime loan from a US bank
2- file for banckruptcy
3- let US treasury buy the debt back and cancel it
4- Profit !
I mean with that they could spend as much as 700 billions !
If I find a golden ticket in my package of ramen noodles, do I get to ride the space elevator?
I got an email earlier today guaranteeing a gain of 1-3 inches in length. It's a start.
You're thinking of making a big tower (like a really large skyscraper). That wouldn't work. You have to approach the problem differently.
A simplified explanation of a space elevator is to take a really long, really strong cable (nanotubes), hang a weight on the end (more cable, an asteroid, lots of metal, etc), and anchor it on the equator. The weight goes out beyond geostationary orbit, and the tension of your cable pulls in on the counterweight to keep it from flying away. The tension keeps your cable taut. You can then run "cars" or "trains" up and down the cable on motorized wheels, most likely with electric power (solar, beamed microwave, or conducted through the cable). Your car can travel nice and slow, and be more efficient than a rocket.
If this doesn't make sense, imagine tying a weight to the end of a string, holding on to the other end, and spinning in circles. The weight will be held out at the end of the string and appear stationary relative to (since you're spinning too). Now put a caterpillar on that string that walks to the counterweight and back to you.
In short, the advantage is that you can use electrical power (which you don't have to carry with you) converted to direct mechanical energy to climb into orbit, instead of expelling fuel (less efficient) that you do have to carry with you. Your vehicle ("car") structure is simpler, more robust, and cheaper than a rocket. The elevator itself would be quite expensive, and requires some advances in materials science, but isn't physically impossible.
The meek may inherit the earth, but the strong shall take the stars.
The elevators traveling speed will be measured in GFIp/t ("Girl from Ipanema" plays per transport).
Do not trust this signature.
actually it's the center of mass that is relevant. The device would be considered in GSO because the center of mass would be there, or minimally lower (a few feet).
There would be roughly evenly distributed mass from earth to GSO, Maybe slightly increasing as it goes up to GSO, and then a large weight beyond GSO.
The idea is to not have it pull up on the ground, or press down (much). Last thing they need is to have a huge chunk of the terminal flung into space.
Self proclaimed typo king, and inventor of the bear destroying coffee table (patent not pending).
In other words, their "space elevator" will probably more closely resember a sleeker rocket/airplane design, and less like an actual elevator...
Given the speed you'll want to haul cargos up to have them there in a reasonable time you'll want some areodynamics.
Even assuming you speed up once you reach upper atmosphere/vacuum, a 22k mile journey at an average speed of 100mph will take 220 hours, or just over 9 days.
I'd see a fuel cell system for in atmosphere lifting, shifting to battery/solar once you're over the atmosphere. Maybe even jettison the fuel cell to be recovered and reused.
Though there is a chance you could use the cable - electrical potential is generated if you string a conductive line through a chunk of the atmosphere, and CF is conductive. You still have the problem of how to utilize that differential at any given point of the cable though. You might end up using a double ribbon system and shipping electricity that way to the cars.
I don't read AC A human right
Can we please not use the word "Boffin" to describe scientists. Its a words used by the British tabloids, usually out of ignorance, and in a derogatory sense.
And as a sub-subnote, this is approximately the cost of developing a complete conventional man-rated rocket launch system. I'm skeptical of the quoted price tag, but it would be extremely cheap if it could be achieved.
That's not the actual price-tag, it's NIF economics. You propose the project with a $9.5B price tag and spend your money providing whatever results you can. You then apologize for failing to complete, but assure the backers that you're nearly done, but need an additional $5B. When that's spent, you've hit a snag so complex that not even the top minds in the world could have seen it coming, but you can finish the project for only $8B more. After all, who wants to abandon a project that you've already spent several years and nearly $15B on when you're so close. Repeat until retirement.
It's amazing how well this seems to work in practice.
He's getting rather old, but he's a good mouse.
Sir Arthur C. Clarke, when asked about when the space elevator would be constructed, he said something like:
Probably about 50 years after everybody quits laughing.
link.
Don't shut the idea, the idea is pretty good, yet the implementation is going to be tricky, with a space elevator, sending a kg. into space will be way more cheap than what is cost nonadays.
DON'T PANIC.
A space elevator essentially just needs certain advances in materials science. It's a big engineering project, but nothing more than that.
AI, on the other hand, is something that nobody in the world has any clue how to achieve. They're simply not comparable. We may very well see AI before a space elevator, but it will be because computer technology advances vastly more quickly than space technology.
And just for the record, I did not claim that FTL is impossible, merely that it's impossible according to accepted physical theory. And that statement is absolutely true.
If you mod me Overrated, you are admitting that you have no penis.
The cross-Britain maglev (16 billion pounds, http://en.wikipedia.org/wiki/Transport_in_Glasgow#Future_Plans) is estimated at approximately twice the price of mankind's rope into space.
So for the price of what Wall street caused US government to pay, you could get a space elevator for each country in the world (almost - the smallest ones will have to share ofcourse)
.ACMD setaloiv siht gnidaeR
I have the solution though. To get around the problem with the long cable and pulley, we can use rocket propulsion on the bottom of the elevator cart.
Also since the shaft it will travel may encouter some problems with radial velocity and all that engineery stuff I know barely enough to be dangerous about, we should cut that out and just create a cart that doesn't need that.
Yeah, a rocket propelled shaftless space elevator. Where's my damn X-prize or whatever money for being so smart....
-- A computer without COBOL and Fortran is like a piece of chocolate cake without ketchup and mustard
You mean the thing that orbits Earth?
So we'll eventually have cable wrapped around our planet like a rubber band ball?
And the moon will collide with Earth?
Good thing you're anonymous. If I had a 'nanotube' I sure wouldn't want to admit it on slashdot. :)
This is exactly how all the people considering this intend to do it. The problem is that the strength of cable required to support its own weight for that distance is huge. It has been determined that a ribbon shaped like a giant flat golf tee (can't think of a better description) will be best.
In short, your plan is the same as the best plan that mankind has so far, but we still don't have a suitable material to make the cable from.
Justin.
(Incidentally, geostat tends to be much higher than 100 clicks (qv 'Low Earth Orbit').)
You're only jealous cos the little penguins are talking to me.
The best counterweight is... another elevator car. If you have multiple tethers and superconducting cable (or another means of transmission), you can use a large fraction of the potential energy of the descending car to power the ascending car.
If you bring net mass down from orbit, you can actually make an energy profit (just on the elevator, I'm not saying that it would offset the costs of hauling propellant, etc, for asteroid miners and such).
If you bring net mass down from orbit, you can actually make an energy profit (just on the elevator, I'm not saying that it would offset the costs of hauling propellant, etc, for asteroid miners and such).
Yeah of course you can't win overall, but nevertheless wouldn't it be totally awesome to bring back a load of minerals from an asteroid and get a "free" lift of your next load of fuel and supplies?
The enemies of Democracy are
Actually, it would take a guy in the spacecraft a minimum of 4.3 years to arrive at Alpha Centauri. In Earth's reference frame it might take thousands of years. I'm saying that you're using the times in the wrong frames of reference.
How disappointing would that be? You get yourself all packed up and ready to go to Alpha Centauri. You're excited, the kids are excited, you're going to be the first humans to ever step foot outside the solar system. It's groundbreaking stuff, you are lauded as heroes as you step into your state-of-the art ship that travels at 60% of the speed of light.
After almost ten difficult years in a cramped interstellar ship, you and the other colonists can finally see your destination. You will forever own a place in the chronicles of human history. And then, you discover than the place was already colonized by humans centuries ago ... the ones who waited until FTL travel was invented back on Earth. They made the trip in a couple weeks. They've been waiting for you ever since.
If libertarians are so opposed to effective government, why don't they all move to Somalia?
No, it's your references which are wrong: if you could get to C your trip (from your view) would be instantaneous, from Earth it would take 4.3years.
As I understand it the popular plan is to not actually attach the bottom end - you have it float around at fairly low altitude over the middle of the Pacific and reach it by conventional aeroplane - at least for the first one, perhaps when the technology's tested we can think about having one with train lines running there. Anyway, with such a "floating" elevator there's no need for absolute precision - if it moves a few tens of meters who cares. Just stick some thrusters on it so that it can be actively stabilized.
I am trolling
You're mostly right. A weight in geosync with a tether hanging down would fall, due to the weight of the tether. What you actually have is a system where the center of mass of the entire system is in geosynchronous orbit. There are two ways you can do this, one is to have a big chunk of mass just the other side of the orbit you want, the other is to have another tether extending outward from the geosynchronous midpoint. There are some advantages to that idea. If you want to go somewhere further than earth orbit, you can go out to the end of the outer tether and start off with a fairly healthy velocity, although constrained to being in the plane of the equator. (although, given that the plane of the equator varies considerably with respect to the plane of the ecliptic over the course of the year, you actually have a fair amount of, well, latitude for lack of a better term, with your initial vector if you have the ability to move around your launch date some.) Second, it makes it fairly easy to run masses up and down the external tether to counteract the mass/acceleration of the elevator on the inner tether. Third, if you for some reason want an environment with near-earth-normal gravity, but want it to be 70k km (that's an ugly nomenclature. and 70 Mm looks too much like 70 mm. How about 7E7 m?) away from the earth, there's a perfect place for it, just hang your lab off the end of the outer tether.
The disadvantage, of course, is that you have to make two long, expensive tethers, as opposed to making one tether and a big block of steel (or whatever) as a counterweight.
Pound! Bang! Bin! Bash! is this a shell script or a Batman comic?
The best way to build a space elevator would be to begin at GSO and build outwards from there, keeping equal mass towards and away from Earth. You can then maintain a stable CoG by having masses at the top and bottom of the elevator structure that can be added or removed as needed. Note that in this design, the elevator is NOT tethered to the ground and is in fact in orbit with a portion coming near the ground. Some form of thrust, likely ionized gas propulsion, would be needed at the top to counteract drag and other wind acting on the lower section of the elevator.
Ignorance is Bliss -- And the Opposite is True -- Genius is Madness
"Japanese Begin Working On Space Elevator"
Did that headline make anyone else feel like we're in one big game of "Civilization"?
He left out the base assumption there, that everyone leaves out.
Once you pay for the space elevator, the incremental cost for sending a KG of cargo into space is cheap.
This is the same statement, less clearly made, as the comment somewhere above here that talks about costs of a space shuttle flight. It says, looking at total program costs, the space shuttle costs $1.3 billion per flight as of 2006, but looking at incremental costs, it is only $60 million per flight.
The unobtanium is, of course, part of the initial cost, and which most people on here seem to think is underestimated in the Japanese announcement.
This is my sig. There are many like it but this one is... Oops. Frank, I've got your sig again! Where's mine?
NASA with the the Italian Space Program tried long (up to 5 km) space tethers several times. Either cable fries and breaks from huge electrostatic charge breakup or the satellite fries. Anyone whose flown a kite with a metal wire knows the problem is even worse in the atmosphere.
The problem is that even the *simplest* form is way beyond what we can produce in the present day, and you're wanting to do a form that's far harder.
In a space elevator, the tether has to be long. Very, very, very long. So much that even if you could build a cable with the density of graphite and a tensile strength of 100GPa, it'd still have to taper severalfold as it reaches toward the earth. With the taper requirement, pulleys are simply right out (can't have the pulley's cable change shape as it goes, now can you?), as is *anything* that can increase the weight of the fiber. You need elevator "climbers", powered by beamed power transmission.
The problem remains the cable. 100GPa with the density of graphite is just so far beyond anything that we can achieve today it's really just a sci-fi concept that people like to dream about. The last I checked, the strongest *individual single-walled carbon nanotubes* that people had directly measured the strength of broke at just over 60GPa. This is for single tubes, let alone bundles of tubes, let alone a bulk fiber, let alone an entire tapered cable. Tubes theoretically can be stronger, but I haven't seen any measurements confirming such extreme theoretical strengths. The strongest SWNT bulk fiber I've read about was planar sheets that were about 10GPa.
Yes, you can build a space elevator with a tensile strength of less than 100GPa. But your taper factor for the elevator rises *very fast* with decreasing tensile strength or increasing density, which means that its mass increases *very fast*, which rapidly puts it outside the realm of possibility. Honestly, something more like 120GPa would be much easier to build, but that's even further from what we can achieve today. I'm not even sure it's physically possible to achieve. SWNTs are pure graphene SP2 structures; how can you get stronger than that? The only thing I can think of that could help us best today's best strengths are complete perfection, every atom of the fiber all the way up, and I'm not sure that would do it.
You don't exist. Go away.
it would take a guy in the spacecraft a minimum of 4.3 years to arrive at Alpha Centauri
The ggp's point is that it would not. If you accelerated quickly enough, time would contract enough so that, in the spaceship's reference frame, the trip would take well under 4.3 light years. In fact, it could take an hour ( if the acceleration didn't kill you ).
What you mean is that, in Earth's reference frame, the trip would have to take at least 4.3 years.
You know, if we just increased the spin of Earth, we wouldn't need as long of a cable to get to GEO.
A unique way to learn a language: http://languageloom.com
At a distance of (iirc) about 2/3rds of the way to geosynchronous orbit, an object dropped off the elevator will be in an elliptical orbit that just barely misses the atmosphere. Anything lower than that will re-enter. With rockets, of course, you could drop things lower and/or achieve round orbits.
Launching from beyond geosynchronous orbit ultimately robs the earth of its rotational energy (something that happens all the time anyways because of tides), so that's not really a big deal for the elevator as long as it can handle the additional tension. It would be a great way to launch things towards the rest of the solar system without wasting fuel.
No... First: any mass at ANY [circular] orbit will remain at the same altitude indefinitely. (You don't see the GPS satellites leaving orbit do you?) A mass in geosynchronous orbit has the additional property that it also stays fixed relative to the earth.
Second, the orbit doesn't need to supply [significant] tension. For every newton of mass you lower towards the earth you simply place an equal newton of mass equally farther out into space. As long as the center of mass remains at the geosynchronous orbit all forces cancel out and the object still stays fixed relative to the earth. The item could reach all the way down and tickle the surface of the earth and yet wouldn't be pulled out of orbit in either direction.
Third, you don't need to solve "the tidy little equilibrium problem." Simply attach the tether to the earth (Ecuador is an excellent spot for this) and place the center of mass slightly beyond geo orbit. This will place a permanent tension on the tether. You can climb with any weight that is less than the amount of tension. You may accelerate with a force that keeps the combination less than or equal to the tension. You can do this without any regard to maintaining any equilibrium. And even if you did it is easily achieved. Simply attach the tether to a winch. Want less tension? Reel the whole thing in. More? Reel it out. The servo control for this would take something like a day to setup.
You need to retake Newtonian Mechanics my friend. The mechanics of this system are easy, well known and have been around since the beginning of the twentieth century. The material sciences is the main thing holding this from being a reality. Carbon nanotubes are the first, and so far only, material which promises the performance we need. (currently 10% of required strength and insufficiently long)
I will never live for sake of another man, nor ask another man to live for mine.
Wikipedia has an indirect link to a 2002 paper where a microscopic nanotube was found to have a tensile strength of 0.15 TPa, which is easily strong enough. Even if that was wrong, I see no reason to expect the theoretical calculations to be so far off as to make a perfect structure lack enough strength. Whether they would last long enough to be useful in a space environment, with all the high energy radiation there, is something I wonder about. Can they be repaired in place as fast as they decay, or how much of a cable's life would be spent hauling up its replacement?
It does seem much too early for the Japanese (or LiftPort) to be getting serious about building a space elevator. I suspect that is more for the buzz, and the genuine hope is that the research dollars they generate will pay off in more mundane uses of super strength materials.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)