5595 Days and Counting 54
Kris_J writes "Seattle PI appear to have been the first to pickup the story that a former member of Highlift ("Space Elevator") Systems has split off to form Liftport. The new company has the impressive aim of a space lift by July 1st, 2018. Competition is supposed to be good, right? If you want to know more they've got a messageboard where you can ask questions."
OK, Bill, here's your chance (Score:3, Funny)
Re:OK, Bill, here's your chance (Score:1, Troll)
I thought it was a "Linux is better than your machine" uptime thingy.
I knew frmo the article that it wasn't talking about my wife's former 98 box!
Re:OK, Bill, here's your chance (Score:3, Insightful)
In 2018, Bill will be 63 years old, by which time he says he will have given away most of his money. Windows NT will exist in the Smithsonian, next to your own favorite operating system, but it is unlikely that either one will be used for projects of this type.
Also, I would hope that by that time, we will pay by the kilogram instead of the pound (hey, I'm an optimist...).
One of the cited uses for the elevator is to build solar power satellites to beam power back down to earth. I wonder if it will be
Re:OK, Bill, here's your chance (Score:2)
I just don't think this stands up to even the slightest reflection. Fifteen years ago (1988) You had a few choices for large scale computing: you could run an and IBM system (MVS or VM), you could run a DEC system (VAX/VMS or RSX-11), you could run an HP based system (MPE), or you could run some form of UNI
Re:OK, Bill, here's your chance (Score:2)
Get real.
You are not running the same operating system you were back in 1988. That is like saying you are driving the same car, because it is a Chevy like the one you have back in 1988.
Back in 1988, I was running 4.3 BSD, System 5 release 2, and Ultrix. I am really glad I am not running those operating systems today. And back then, I was really glad I was not running the UNIX version 6 that I learned C on back in 1976.
It is unlikely that the space elevator will be running Windows NT, and also unl
I think you got the economics wrong. Physics, too (Score:2)
You are making two assumptions in the above statement:
The first assumption is debatable, and the history of batteries shows that the second is extremely suspect. The suitability of a solar-electric energy supply for our whole economy
Re:I think you got the economics wrong. Physics, t (Score:2)
Who needs batteries?
It is currently cost effective to put solar panels on your roof, and generate enough power to run your electric meter backwards feeding the grid. The break-even period is less than 10 years for a system that has a 30 year warrantee.
At the end of the month, you have generated more power into the grid than you took out.
How the grid chooses to store that power is quite flexible. It can simply offset the power that would otherwise be used from hydroelectric dams, allowing those to
You forgot... (Score:1)
You know, that whole thing with collecting energy in space and blasting it to Earth in the form of tight-beam microwaves?
Thankfully, this sort of system does not require one to depend on roofs.
Not so (Score:1)
Re:OK, Bill, here's your chance (Score:2)
(yes, yes I know hog's heads are volume, but hey...too much pie is my problem)
Re:OK, Bill, here's your chance (Score:1)
Manager: Hey Bob, you sure you can handle controlling the space elevator's descent?
Bob: Yeah boss, I can do it. (Bob's computer starts acting funny.) Hey, wait a minute... my computer is going nuts. BOSS, THE ELEVATOR'S GOING BACK UP!
Manager: WHAT!!
Bob: Wait, it's coming back down. I think everything's okay now. I have control back. (Bob starts to control elevator again, then his
Re:OK, Bill, here's your chance (Score:2)
Re:OK, Bill, here's your chance (Score:2)
Think it'll be ready by then? Always the optimist, eh?
Re:OK, Bill, here's your chance (Score:1, Offtopic)
Yeah investing in this plan would definitely be better than wasting almost $5,000,000,000 [gatesfoundation.com] on global health and education initiatives. What an evil bastard!
Re:I'm willing to bet $$$ it will never work (Score:4, Informative)
Of course, the article also points out that the exact material has yet to be made...
Re:I'm willing to bet $$$ it will never work (Score:5, Insightful)
You're missing something here: the difference between science and engineering. Space elevator advocates often point out that most of the remaining problems are not in the realm of science but instead tech and financing. So progress is not dependent on some long haired genius in a basement lab having a brainwave. You can make confident predictions that technology will improve and that the material with the required tensile strength will be constructed soon in the future. And hey, considering that these guys are trying to accomplish the mind-boggling, optimism is the only way.
Re:I'm willing to bet $$$ it will never work (Score:3, Insightful)
I agree except for the "soon" part.
Even predicting the recent past can be tricky. (Score:3, Informative)
Start cheering then. We have the means to manufacture them in quantity now [foresight.org]. (Basically, continious process vapor deposition, with a few tricks to it).
The present problem is the old "how do they stick the teflon to the pan" problem; getting them to play nicely in composites, and finding ways to ma
Re:Even predicting the recent past can be tricky. (Score:2)
When I asked a polymer chemist friend about this, he said that longer fibers would solve the problem. This suggests that we cannot yet manufacture fibers long enough to be useful in composites.
Re:Even predicting the recent past can be tricky. (Score:2)
AFAIK, that has been a popular theory for some time, and will be hard to quash since it is unfalsifiable; if the fibers aren't working, they must still not be long enough. But at present making longer fibers is literaly "only a matter of time;" with a continious deposition process, the longer you let it run, the l
Re:Even predicting the recent past can be tricky. (Score:2)
My understanding is that this is not correct. The nanotube fibers cap themselves after a certain average length (consistent with this being a random process with low but significant probability). Leave it on, and you get more fibers, not longer. Last I heard they were experimenting with different additives, as various metals inhibit capping for
Re:Even predicting the recent past can be tricky. (Score:2)
See the link in my first post of this thread. This came up in the presentation of the paper I attended, and the basic answer was (as it often is): process control. IIRC, large area / low temp / slow deposition biases the yield towards longer tubes.
-- MarkusQ
Re:I'm willing to bet $$$ it will never work (Score:2)
Re:I'm willing to bet $$$ it will never work (Score:2)
Re:I'm willing to bet $$$ it will never work (Score:5, Insightful)
you still have to accelerate to orbital velocity after the lift, unless they plan to build it all the way out to the distance of a geosynchronous orbit.
They are going way past the geosynchronous point; they *have* to because the lift's center-of-mass has to be at the geosynchronous altitude.
Nothing is strong enough to support that kind of weight. With today's best engineering, they haven't even managed to build a building 1/2 of a mile high.
You shouldn't think of it in terms of a weight-bearing structure like a building. The lift ribbon will not need to support the weight of the whole system; on the contrary, centrifugal force will hold it aloft (i.e., the whole thing is effectively in orbit).
So, the material needs tensile strength, not weight-bearing capacity. Think carbon nanotubes, not "diamond beams".
But right now it's ridiculous and any venture capitalist who gives them money would have to be borderline retarded.
Ignorance has a cure: RTFA
Re:I'm willing to bet $$$ it will never work (Score:1)
A hanging steel rod or fibre will break under its own weight already at a length of about 10 km. The article mentions that the carbon nanofibers are 30x stronger than steel, which means that you get 300 km. M
Re:I'm willing to bet $$$ it will never work (Score:2)
That's why the grandparent post mentioned *tensile* strength rather than *load-bearing* capabilities; you need somet
Re:I'm willing to bet $$$ it will never work (Score:2)
Re:I'm willing to bet $$$ it will never work (Score:1)
Incorrect reasoning. Suppose that you have your rock locked in a geostationary orbit. Then you unwind the cable: the cable hangs down from the GS orbit. (the roundtrip time for an orbit decreases with decreasing altitude; since everything is forced into a 24-h roundtrip time, the cable does HANG or otherwise it will fall down). In other words, the cable needs
Re:I'm willing to bet $$$ it will never work (Score:2)
Still, I don't think it's too hard to believe that the cable will be capable of withstanding the tensile forces of its own weight pulling on it. Individually, a nanofiber might break under its own weight, but collectively, as a woven mesh / rope, it will have a much higher tensile strength.
Re:I'm willing to bet $$$ it will never work (Score:1)
I would say that the enforcing effect of a cable instead of a single beam is that
1. a local rupture cannot propagate; just one fiber breaks, but not the whole cable.
2. the system gets some elasticity such that sho
Re:I'm willing to bet $$$ it will never work (Score:1)
Not sure if that particular figure is accurate, but it sounds ballparkish. The reason the numbers don't seem to add up is that the gravitational pull will drop off with altitude. At the geosync point, where most of the mass is, the cable will be weightless (as it is in orbit). At the bottom, the ca
Re:I'm willing to bet $$$ it will never work (Score:1)
Yes, gravity drops off with 1/r^2 where r is the distance to the center of the earth. The first 300 km are not really significant compared to the radius of the earth which is 6400 km.
Anyhow, let's do it exactly. A segment of cable with length dr and a density (per length unit) rho has a mass dm=rho*dr. On this segment, two forces act:
1. Gravitional force
Re:I'm willing to bet $$$ it will never work (Score:1)
According to this page [highliftsystems.com] (which I'm not sure how much to trust due to bias, but has similar figures to what some Googling turns up), carbon nanotubes buildable in the forseeable future have a theoretical tensile strength of 130 GPa (versus current laboratory nanotubes having a measured tensile strength that varies in the range of about 10 GPa to 60 GPa, according to Google) and have a density of 1300 kg/m^3 = 1.3E-3 g/mm^3 (or 1.3E-3 kg/m for a 1 mm^2 bundled nanotube cable, which is pretty close to your plug
Re:I'm willing to bet $$$ it will never work (Score:1)
dFc = dm w^2 r,
F = INTEGRAL(r0..R) (dFg - dFc)
= INTEGRAL(r0..R) rho dr (g0 r0^2 r^-2 - w^2 r)
= rho [g0 r0^2 (1/r0 - 1/R) + w^2(r0^2 - R^2)/2].
With rho=1.3e-3 kg/m (updated value); R=3.5e7 m, r0=6.4e6 m, g0=9.8 N/kg, w = 7.3e-5 rad/s, we get F = 6.3e4 N for the tension on the cable.
2018? (Score:1)
possible, but... (Score:3, Insightful)
Seeing as they are going to the general public, I guess that they don't have stable long term institutional investors for their long term project. That means they are searching for lots of piece-meal investments to keep a capital intensive project going for fifteen years. That sounds pretty hopeless to me.
I'd guess that what they're really after is money, in the name of the project. Perhaps the other partners saw this and that is why they left the original coalition.
Relationship? (Score:2)
It's Official (Score:4, Funny)
Re:It's Official (Score:2)
On that basis, so is Michael.
Your key to space (Score:2)
I wonder what kind of industries will spring from this. People may be able to get on an elevator, climb to several miles in the sky, strap on a parachute and jump off. Others may try to see how high they can climb under their own strength. Of course, the higher you go, the e
This just in... (Score:2, Funny)
moderators with axes to grind (Score:1, Offtopic)
"Troll -- ... This is a prank comment intended to provoke indignant (or just confused) responses. A Troll might m
uh oh (Score:1, Offtopic)
Unless one is wearing ruby slippers, that is considered a rather menacing gesture by many, in particular when accompanied by unintelligible toasts and an extended arm (holding a glass softens the effect, I suppose).
Fantasy (Score:1)
Hopeless romantics (Score:2)
Wow, those crazy optimistic people. Given the existance of a working commercial cargo elevator, those hopeless romantic optimists will go even further and begin dreaming anew of "someday" using it to lift a real live person. Kooky guys indeed.
What's wrong with a tower anyway? (Score:2)
Sure, maybe a steel cable could never work, but at some scale it must be possible to build up a tower or, alternately, to build down a beam of of interconnected steel tubes.
Building down it seems we could use steel beams made of elaborate geometries like we s