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Calling the Space Elevator
CornfedPig writes "SPACE.com has an article that suggests building an elevator to a 100,000 km-high penthouse could be possible within the next few years at a cost of about $5B US. Widespread availability of low-cost carbon nanotubes appears to be the gating factor. Existence of such an elevator could drop the cost of lifting things (satellites, people, CowboyNeal) into orbit to a couple of hundred dollars a pound. Anyone remember Clarke's The Fountains of Paradise?" Space elevator stories come along every few months; we never seem to be getting any closer to actually doing it. I imagine it will happen at some point in my lifetime, but...
Remember what is required, first. The thing has to come reasonably close to the ground in order to be useful. And the center of mass has to be at geosynchronous orbit height, 100 km up. That's a huge amount of mass spread over a very large area. This incurs several problems:
Even if carbon-nano tubes form the magically strong and light material for the main cable, there are still plenty of issues to be solved, especially regarding stabilization. You have to deal with forces from wind and weather, tidal effects from the moon and other planetary objects, etc.
A man without a God is like a fish without a bicycle.
This is the type of thing that would have to be so heavily guarded that it would be a serious pain in the ass to use. There would most likely have to be some sort of wide radius no fly zone around it, as well as a very invasive search for anyone wanting to ride up. Very soon the reasons for not doing this will no longer be technical, but rather political and organizational.
When I want your opinion I will beat it out of you.
Whenever I look at the Towers of light and the enourmous hight which it rises into the atmosphere.. I wonder if this is what a space elevator will look like. One of the striking things about it is how far the light penetrates into the upper atmosphere. From my rooof, 2.5 miles away, I was able to get a fix on the angle to the top and place the highest point I could see at about 15 miles up!
For those of you who do not live out here, all I can say is that tv and photos simply do not do memorial any justice. It provides a humbling sense of scale when looking up into the infinity to which it rises.
Ok, I admit it, I submitted the slashdot story before last on this topic, and I linked to the same paper that was mentioned in the next story, and this article is a piece on the same guy who wrote the same paper.
Technically, the bottom line is:
No we can't do this right now. The fibers aren't strong enough to do this without bankrupting the global economy. An exponentially tapering fiber can theoretically do this at any time, but it would be wayyyyyy too big and heavy to install. (e.g. a steel cable would be ~hundred meters wide at the thickest point, and >38000km long...)
For the suggested construction technique, the carbon 'rope' needs to be able to give 72.5 Gpa strength, plus safety factor (typically 2). A single fiber gives about 73 Gpa right now. So we've no safety factor at all... but:
Joining the individual fibers together- nobody has done this whilst maintaining enough of the strength. Splicing normally soaks up 15-30% of the strength, and so we're now 15-30% down on the required strength, and nobody has even managed to do splices this good with carbon fiber.
Only a little percentage off then, but this pushes the mass up incredibly when you do the maths.
Still, we're very close. 3 reasonably simple(?) breakthroughs (one to gain strength, one to splice the rope, one to actually scale up production from one 3cm fiber to trillions of 3cm fibers in a reasonable time) and we're saying 'Hi!' to the rest of the solar system.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Correct me if I'm wrong, but doens't using a space elavator to lift things steal from the angular momentum of the earth? I mean, you'd only lose a negligable amount from lifting satellites, and space stations, but CowboyNeal? I don't want to end up on the "permanant dark side of the earth".
If we had a few hundred space elevators on the planet, how long would it take before we could move the entire mass of our planet into space?
Given the length of time your ride on the space elevator and for the consideration of others. PLEASE do not ride the elevator after eating mexican food.
Thanx,
-The managment
"as plurdled gabbleblotchits on a lurgid bee" - Prostetnic Vogon Jeltz. (One man's humorous is another mans flamebait)
That was great!
Good judgement comes from experience, and experience comes from bad judgement.
- W. Wriston, former Citibank CEO
Are there any astro uber geeks that can comment on the stability of this system from the standpoint of
- small changes of mass from the upper end of the elevator (like from space objects hitting and sticking, etc.)
- small oscillation modes (rubber band like) in the connecting fiber
Otherwise, I'd be Real Nervous® about having the base station of the elevator anywhere near MyBackYard."Provided by the management for your protection."
Dr Fish
A factor in space launches IIRC is the wind velocity in the upper atmosphere, which at times can reach hundreds of knots. I also recall that the high wind velocity was a factor in the post-explosion breakup of the Challenger space shuttle.
Although the atmospheric density and pressure is much lower at these altitudes (50-1000km+), the wind force is a factor, and it makes me wonder how a geo-stationary elevator shaft could be designed to withstand the energy of such wind forces.
If it could work, it'd probably kick off a revolution in space industry.
Big Daddy, Johnny, Burp, Aunt Zelda, Scott, Slurp, Big Momma
As other posters have noted, we don't have any
materials strong enough for an elevator all the
way to geosynchronous orbit, so it's a bit too
soon for anyone to claim we could build one in
the next 10 years.
HOWEVER, we do have materials strong enough for
a "hypersonic tether". This'd be a much shorter
tether, only a few thousand km long, and moving
at a good clip around the Earth, with the lower
end just above the atmosphere.
With this in place, you could use cheap sounding
rockets, just barely capable of making it out of
the atmosphere, to rendezvous with the tether as
it swept past. The cargo would be grabbed by the
tether and snatched up into low orbit, while the
sounding rocket fell back to Earth.
There aren't any good online references, but you
can find USENET discussions of the technology on
Google Groups, keywords "hypersonic tether".
>;k
This article totally forgot about the mass in space to anchor this tether. It would have to be at least
the mass of the tether.
Well?
You mean like the exclusion areas that (25 miles, IIRC) that are already established and working around launch areas? (And that were patrolled on launch days before 9/11).
If you read the article, the current proposal is to put the earthside connection somewhere on a platform in the middle of the Pacific Ocean -- this should not be that difficult to handle.
...now that's an oxymoron...
The BIG DIG i think is now over $12B although it was origainally estimated to cost $2.6B
The chief scientist at NASA Langley, Dennis M. Bushnell, gave a talk at my university a few weeks ago. He discussed several dozen *very* out-there ideas (personal auto-piloted helicopters for the masses within ten years, for example), but when asked about the viablility of the space elevator concept he dismissed it outright as a pipe dream.
What i want to know is, would this be a good thing to invest it? They say it will cost $5bn, so they need money from SOMEWHERE, right?
So say if i had a significant amount of money.. like $1million (hell, $500,000 or $100,000) and invested in the construction of this thing (or invested in a company that is constructing it by buying shares), would this be a wise investment, with good return?
Would direct investment by supplying monies for construction and then demanding a % share of profits operating the elevator forever into the future be better then just buying shares in a company that is producing the elevator?
Any thoughts?
I'm always wondering what would be a very good sure bet for investment with VERY good returns, and something like these seems to be an ultimate one. The benefits of a space elevator are simply amazing, and the elevator will be in use for decades if not centuries, until replaced by something better, or a better elevator..
Martin.
You can tell how powerful someone is by the magnitude of the crime they can commit and be able to get away with.
If recoup energy on the caspsule or whatever's desent you might get some interesting fare pricing:
One way trip to orbit: $5000
Return Trip:$3000
PS didn't this appear in the book Fountains of Paradise by Author C Clarke?
And on duty when that cable needs changing, or even just some oil!
All your moderations are belong to me.
"Oh, hello Mr. Tyler. . . going down?"
!#@%*)anks for hanging up the phone, dear.
could be possible within the next few years at a cost of about $5B US.
Since development started in the early 1970s, the U.S. has spent over $180 billion on the space shuttle program. And what do we have to show for it? Certainly not reliable, low-cost access to space!
$5 billion for a space elevator would be the bargain of the millenium.
That that is is that that that that is not is not.
For this idea to work its got to get past both the airline companies and their business partners that are setting up the old "Fly to outer space with 1,000,000 frequent flier miles (plus a hefty sum of money)". This assumes of course that there would be an option for tourism, but considering all the non-astronauts that are signed up for trips to the space station, I'm sure it would happen with this as well. I doubt those guys would appreciate losing business.
In his book 3001, the Earth's equator is studded with a series of tethered space platforms. Clarke's vision of these things includes a lot of interesting detail that I suspect is accurate.
[in abnegation of my nick...]
Dr. Robert L. Forward in his 1995 book Indistinguishable from Magic, provides quite a treatise on the concept of Space Elevators or "Beanstalks" as the particular chapter is called.
Forward has the scientific credentials to justify the idea with excerpts from existing studies to determine the physical and structural specifications of the tether.
Forward also describes a variation on the tether idea that he calls a Rotavator- and that I've seen elsewhere called a skyhook; a rotating cable 8500 KM long in orbit at 4250 KM that dips down into the atmosphere moving at such a rate to allow it to pick up cargo/passenger modules from the earth's surface and swing them up into orbit for release at the apex of the swing either to go into orbit or meet up with an orbiting terminal.
...Probably the most lucid explanation of the physics and material requirements for space elevators that you'll find in print...
[silent once more]