Scientist Sees Space Elevator in 15 Years 503
bofh31337 writes "Scientist Bradley C. Edwards, head of the space elevator project at the Institute for Scientific Research, thinks an elevator that climbs 62,000 miles into space could be operating in 15 years. He pegs the cost at $10 billion, a pittance compared with other space endeavors. 'It's not new physics--nothing new has to be discovered, nothing new has to be invented from scratch,' he says. 'If there are delays in budget or delays in whatever, it could stretch, but 15 years is a realistic estimate for when we could have one up.' NASA already has given more than $500,000 to study the idea, and Congress has earmarked $2.5 million more."
Re:Kick Ass (Score:5, Informative)
There would need to be. At any reasonable speed, you're looking at a 24 to 48 hour trip.
No new news (Score:5, Informative)
The current issue of Discover magizine has a much longer and more informative writeup.
Re:wow (Score:3, Informative)
I mean, the thing is, chemical rockets will only take you so far. So it's money well spent, for what the potential benefits would be.
2 years to work out nanotube materials??? (Score:1, Informative)
There wont be any space elevator anytime soon.
Phil Condit
Boeing
Re:How Far? (Score:5, Informative)
Re:How Far? (Score:4, Informative)
Re:Correct me if I'm wrong... (Score:3, Informative)
Or not... (Score:4, Informative)
Uhhm, even in his book, Edwards admits that the carbon nanotubes needed to make this work just aren't there yet; while we can manufacture nanotubes now, we can't make them as strong (by a factor of around 100) or nearly as long (by a factor of 10,000 or more) as needed. While it may well be that, as soon as someone really puts some effort/research bucks into making stronger/longer nanotubes, they will happen, but it seems like 15 years might still be optimistic.
OTOH, this would be way cool, and maybe in my lifetime to boot...
3001 The Final Odyssey (Score:2, Informative)
Re:How Far? (Score:3, Informative)
Re:Arthur C. Clark (Score:3, Informative)
Technology is advancing at an incedible speed. (Score:2, Informative)
http://www.nature.com/nsu/040308/040308-10.html
http://www.technologyreview.com/articles/rnb_041
Re:3001 The Final Odyssey (Score:2, Informative)
He wrote about it long before then in a book called The Fountains of Paradise.
Re:Where's the tower? (Score:3, Informative)
Re:A space elevator will not happen in 15 years... (Score:4, Informative)
Better RTFA, and maybe do a little research. We are actually within a factor of two of having materials strong enough; anything after that becomes essentially an engineering problem.
Re:wow (Score:5, Informative)
Then there's the "fiber" problem. Nanotube fibers are at best held together by Van der Waals force. Edwards proposes some sort of unexplained "nanotube epoxy" that is somehow supposed to be able to withstand these incredible tensile strengths which the tubes themselves, even in theory, can barely withstand. I don't buy it one bit. The best fibers made so far, held together by the same forces, achieve the sort of tensile strength you get from Kevlar. Longer tubes will help, but you'd need a *huge* improvement.
The epoxy concept is bunk. There is a concept which might work, however: pressure induced interlinking of carbon nanotubes [arxiv.org]. Basically, you swap out some of the stronger sp2 bonds for the weaker sp3 bonds, but it interlinks the tubes.
I have other problems with Edwards' design, too, but he has done an awful lot of well-reasoned calculations. I contributed a lot to the article on Wikipedia, so if you want to read more about space elevators, that's the place [wikipedia.org].
Erm, uh, no. (Score:2, Informative)
Slashdot.org [slashdot.org]
Re:I'd volunteer to be an elevator attendant (Score:5, Informative)
Re:Not for passengers (Score:3, Informative)
Re:How Far? (Score:3, Informative)
Re:A little more humility is in order (Score:2, Informative)
Of course, studies showed people freaked out if there weren't any bolts in the wings. I think they glued fake ones on for a while....
Re:Radiation (Score:5, Informative)
Re:Not for passengers (Score:5, Informative)
I think the idea for this is using the elevators to lift the mass up to an appropriate altitude and letting it go. Part of the mass is a booster rocket to get the mass into the appropriate orbit. It'd take a whole hell of a lot less rocket fuel to do this than to launch it directly from Earth's surface. Taking the mass to an altitude above geosynch and letting it go would give it a huge boost for getting out of Earth's gravity well. As far as efficiency, they are planning on driving these things with lasers powered by solar cells. I forget the exact details, but they imply that the propulsion systems are one of the easier components to develop for the project.
IIRC, the main rebuttal for this is that the cable will be much wider than the minimum required for the target maximum liftable mass, and that there will be "repair lifters" that go up on occasion to patch holes in the ribbon cable. For the larger, trackable space junk masses, the cable will be tied down to a mobile oil rig platform to allow for evasive maneuvers.
Above geosynch orbit altitude, masses "moving" (quoted because it depends on your reference frame) at the speed at which the weighted end would be moving tend to want to leave orbit. Put simply, things trying to maintain synchronous orbit (staying over one spot) below geosynch altitude want to fall (not moving fast enough), things at geosynch altitude stay where they are (speed is just right), and things above goesynch altitude want to leave orbit (moving too fast). For example, the moon's orbital speed is 1.03km/s (about 2200 mph, or about Mach 3), performing one revolution every ~28 days. The speed of something maintaining a geosynch orbit at 60k miles would be insanely fast, revolving once a day (at that altitude, it would be moving at ~7.5km/s). That would put a lot of stress (not sure how to calculate that) on the ribbon, which is part of the reason it needs to be so strong. The centripetal force would keep the cable taut. The weighted end would be quite massive, enough that the relatively small mass of the lifter and its cargo wouldn't cause enough of a change in mass to the elevator system as a whole.
Also, if the cable were to be in danger of getting dragged down, they'd probably just let it go, and the weighted end would rip the ribbon out into orbit and away. I don't think they are too worried about it getting dragged down, based on the designs I've read about.
The article in the recent Discover goes into more depth than the article attached to this thread... it even goes so far as to claim that many of the scientists that attend these conferences end up signing on to help the Space Elevator along towards being realized.
Re:Arthur C. Clark (Score:3, Informative)
He wrote "The Fountains of Paradise", another book about a space elevator, in 1978.
As I recall the "shaft" of the elevator was made with a special new material that has the strength of steel at the molecular level. I.e. a strand of it one molecule thick could not be broken and was also super dangerous as it could cut through almost anything.
Interesting concept, but I guess we don't really need that stuff after all...
$500,000? At NASA? (Score:4, Informative)
That's not all that much money at NASA, it's the equivalent of 2 Full Time Equivalents (FTEs), plus a little bit of equipment to work with.
Re:A space elevator will not happen in 15 years... (Score:3, Informative)
We're nowhere even remotely close to > 100GPa; we're so far off, it's painful.
The best we can currently do on any sort of measurable scale is synthesize diamond via CVD at a rate of millimeters per hour. CNTs, should they somehow prove to have better strength than the experiments thusfar have shown (at best 60GPa), would have to scale up without losing that strength (quite difficult, if not impossible)
Re:A little more humility is in order (Score:5, Informative)
When, exactly, did the production of steel on a scale that one could build a bridge out of the stuff begin? Iron, too, for that matter? Certainly not thousands of years ago.
Furthermore, it was mostly the math that needed improvement, not the materials.
Re:Not for passengers (Score:3, Informative)
Which is exactly the plan. A counterweight at the far end can be adjusted to position the center of mass exactly in geosynchronous orbit.
Re:Where's the tower? (Score:3, Informative)
Um, no it isn't. In a vacuum (where terminal velocity doesn't really make sense anyway) they would go the same speed, but in an atmosphere (which our planet has if you hadn't noticed) terminal velocity very much differs. Or are you suggesting that if you drop a cannonball and newspaper from an airplane they will reach the same speeds. Terminal velocity is the speed at which the atmospheric drag balances the weight of the object.
Re:The Panama Space Canal (Score:5, Informative)
Actually the plan isn't to build it in any country. The proposal is to use a floating platform converted from an oil drilling rig. There's a lot more suitable ocean than land, and an ocean platform could be best situated for good weather, and even moved a bit to dodge larger bits of debris. A platform out in the middle of the open ocean would also be less accessible to terrorists.
Re:The Panama Space Canal (Score:2, Informative)
At 8 north it's not to far off the equator so another plus. Add to that the lack of any populous areas near it and I'd say we have a winner.
Re:what if the thing collapses? (Score:2, Informative)
slashdot.org [slashdot.org]
Re:15 years? (Score:3, Informative)
Power. It takes an incredibly large amount of power to climb 38000 km to geosynchronous orbit.
It's ~500 KW per tonne of elevator to go at 200km/h near to the ground, but weight gradually reduces as you get nearer to geosynchronous orbit, and away from the earth and the power scales down proportionately.
The problem is, you can't carry enough fuel to get to the top (unless you use nuclear, but that's heavy).
Brad Edwards plan involves using ground based lasers to power photovoltaic panels.
Re:Correction (Score:2, Informative)
We need some New Physics to Discover from Scratch a New Material that can be used to bond the nanotubes together in sufficient density because NO SUCH THING exists right now.
And, about your 386 analogy