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What research do you base this statement on?

The NASA feasibility study from the mid-90's.

This is completely ridiculous. If that's true, why don't we already use wireless power?

Because doing a whole house like that would take a lot of power, cause a lot of RF interference, and probably react badly with pacemakers. In any case, we're not looking at powering a bunch of light bulbs over an area, but rather beaming power to a specific target. A later study (PDF link) discusses using a laser for this purpose. Microwaves are also possible.

All of that sort of stuff has already been covered. The only real problem is the (possibly insurmountable) issue of cable strength.

Take a piece of metal and move it through an electric field, such as one generated by the earth, and you will build up charge.

Space elevators are geostationary. Of course, they'll have oscillations (induced by troposphere winds, climbers, the moon, etc), but when it comes to oscillation, building up a charge would be a *good* thing. It'd act as damping. It's not like something with such a tremendous length with razor-sharp edges would have any sort of trouble getting rid of the charge through coronal discharge to the ionosphere.

All of this sort of stuff has been considered before in Dr. Edwards' paper. Sadly, the one key, critical issue is skimmed over: strong enough SWNTs. This is the only real limiting factor on a space elevator, and it may well make a space elevator (at least for Earth) physically impossible.

I have been following this for some time... Here are a few links for ya.
http://www.isr.us/Downloads/niac_pdf/contents.html Study
LiftPort Group. Company wants to beat NASA.
Reference Site



Place a curse on the RIAA/MPAA

Yes, lightning is a definite hazard for a space elevator.

The solution: locate the space elevator in a lightning-free area.

Well, specifically, no storms powerful enough to damage a space elevator or its base station... details here

I hope you won't mind living in a houseboat... :^)

Um, you can go to infinity and not escape the Earth's gravity well.

The critical factor is how fast you're going in relation to how hard gravity is pulling on you. When you're in geosynchronous orbit you're moving fast enough to stay forever at the same height. If you're HIGHER than geosynch, but still moving at the same speed (1 rotation / 24 hours) you're going to drift AWAY from Earth if you let go. If your cable is long enough you can go a LONG way away. A 62,000 mile cable is more than enough to go to Jupiter (http://www.isr.us/Downloads/niac_pdf/chapter7.htm l). If you just want to go to the moon you're going to want to cast off from the cable at a significantly lower altitude, otherwise you're going to make a BIG crater.

Kind of fluffy but a little interesting graphic.

I have been following the progress of research concerning space-elevator for some time now. The LiftPort Group of companies working towards a space-elevator are making a great deal of progress. See here and here for more LiftPort specific information. Slashdot reported on the faa approval of their high altitude tests several days ago -- refer to that thread for some interesting discussion. Check here and here here for several reports concerning the viability of the elevator -- be sure to check the NIAC pdf. Also, Blaise Gassend has a great collection of information. Finally, though carbon nanotubes are still in their infancy (its been a little over 12 years since they were discovered) - their theoretical tensile strengths are perfect for use in the construction of a space elevator tether. This recent development spells a rosy future, and many innovations yet to come.

I have been following the progress of research concerning space-elevator for some time now. The LiftPort Group of companies working towards a space-elevator are making a great deal of progress. See here and here for more LiftPort specific information. Slashdot reported on the faa approval of their high altitude tests several days ago -- refer to that thread for some interesting discussion. Check here and here here for several reports concerning the viability of the elevator -- be sure to check the NIAC pdf. Also, Blaise Gassend has a great collection of information. Finally, though carbon nanotubes are still in their infancy (its been a little over 12 years since they were discovered) - their theoretical tensile strengths are perfect for use in the construction of a space elevator tether. This recent development spells a rosy future, and many innovations yet to come.

Please also see the NIAC paper, it has lots of answers (and uses official, correct terms, unlike my ad hoc abbreviations).

http://www.isr.us/Downloads/niac_pdf/contents.html

You should also be aware most designs now call for a ribbon, as opposed to a cable.

That's addressed here:
http://www.isr.us/Downloads/niac_pdf/contents.html

Phase I NIAC Paper

See the sections on meteors and impact of breakage.

Please see:

http://www.isr.us/Downloads/niac_pdf/contents.html

Phase I NIAC Paper

http://www.liftport.com/faq.php

Frequently Asked Questions regarding the SE endeavour, from LiftPort Group

There's a very cool article on this. It goes into great detail about the actual implementation and other challenges such as safety. I think this is an actual research paper written by NASA as part of their advanced R&D program looking into realistic plans for building a space elevator. The guy who wrote it is a major reasearcher in the field.

The LiftPort Group of companies working towards a space-elevator are making a great deal of progress. Slashdot reported on the faa approval of their high altitude tests, for example. See here and here for more LiftPort specific information. Check here and here here for several reports concerning the viability of the elevator -- be sure to check the NIAC pdf. Blaise Gassend has a great collection of information. Finally, though carbon nanotubes are still in their infancy (its been a little around ten years since they were discovered) - their theoretical tensile strengths are perfect for application in a space elevator construction. This recent development spells a rosy future, and many innovations yet to come.

The LiftPort Group of companies working towards a space-elevator are making a great deal of progress. Slashdot reported on the faa approval of their high altitude tests, for example. See here and here for more LiftPort specific information. Check here and here here for several reports concerning the viability of the elevator -- be sure to check the NIAC pdf. Blaise Gassend has a great collection of information. Finally, though carbon nanotubes are still in their infancy (its been a little around ten years since they were discovered) - their theoretical tensile strengths are perfect for application in a space elevator construction. This recent development spells a rosy future, and many innovations yet to come.

Here's a cite. Edwards is hardly an idiot, and has researched very extensively on the subject. I'll sum up the two methods:

Laser: without adaptive optics, the concept is all but dead in the water. Adaptive gives the needed focus over the critical range. The best currently available high power laser has an efficiency of 3%. The best cells to go with that laser are 59% efficiency, 82% filled at that frequency.

Microwave: 2.4, 35, and 94 GHz were considered in multiple separate studies, with different kinds of antennae. With a 3 meter antenna on the considered space elevator climber (on the ground you could support much larger to get better efficiency, but not nearly enough improvement), the overall system efficiency with the best choice (94GHz) is a mere 0.05% (10 times worse than I remembered).

better figures from Russia

The 7k$/kg *is* from Russia (China is the same price, and so is a Delta-IV heavy. Ariane V is 10k$, and shuttle prices vary, but are usually 13-18k$/kg. Falcon IV, if it actually comes into existance and lives up to its promises (I have my doubts, but here's to hoping!) will be 2-3k$/kg.). You can sometimes get better deals - for example, the planetary society got a good deal on (very faulty) Volnas; however, this is not general-case, but simply excess hardware disposal.

if only for fuel

Fuel is cheap. Dirt cheap. If you can get fuel to be a measurable portion of your launch costs, you're doing things *right*.

And 150 acres gets only about 180MW

For the price of *one* kilogram of your space infrastructure simply to be *launched*.

don't think it's worth using up land

Apparently the sellers of the land do. You could probably get even better of a price than 40-50$ an acre in places.

as it erodes, say in sandstorms

Or as a space system erodes in, say, radiation, micrometeorites, debris, and atomic oxygen bombardment, with a ridiculous repair/maintenance cost.

Well, those issues are actually addressed in Dr. Bradley Edward's proposal. His calculations are actually quite well done, extending to everything from power to heat dissipation. There are only a couple major bits of handwaving that he does:

1) (biggest issue) he assumes the requisite >100 GPa fiber
2) his harmonics calculations seem oversimplified
3) (lesser) his assumed laser efficiency numbers seem high, but the transmission and receiving technologies are advancing pretty quickly, so it's not that unrealistic of an expectation.

The climber powering is to be done with direct power beaming; he considered both microwave and laser, and found laser to be notably more efficient (although both are quite lossy). The laser would be optimized for penetration of our atmosphere (of course) and beamed with adaptive optics, while the photovoltaics would be optimized for the frequency of the laser.

You don't need a counterweight heavier than each payload because the elevator extends far beyond GEO, so any counterweight at the end (or additional cable) maps to much more tension on the cable. You do induce harmonics, however, when you climb, which I'd like to see a lot more in-depth work on. The dampening in space comes from the tension of the string and its linear density.

CNT ropes are highly elastic, so that's not a problem. There are solutions to climbing it that have been discussed on the forums if for some reason enough traction couldn't be gotten - for example, toothed climbers with a gap-containing or meshed cable.. There are many, many more problems that he has to deal with, of course - micrometeorites, atomic oxygen in the upper atmosphere, solar and cosmic radiation, space debris, lightning, wind, heat, motor stresses, deployment, etc, and the calculations for those are done, as well as charge buildup calculations.

A lunar elevator is possible, but preposterous in length. A Mars elevator is much simpler than an Earth elevator, but you have to get your materials to Mars or make them locally (and since they can't be made in the first place with current tech...). Plus, to toss payloads between Earth and Mars, you have to do plane and general trajectory corrections.

Did you actually look at that map before your posted? Your map doesn't show any information about lightning frequency over the oceans.

This page contains the information you were looking for.

http://www.isr.us/video/SE-INTRO_Final-1stream-384 .wmv

Covers the basics of the elevator, what it looks like, how it works, etc...

The question of how this thing is powered never popped into my head before, but the video shows that they will use a lazer shot from the base station. Crazy stuff.

> burning up or fluttering to the ground like heavy cloth.

Actually more like a loooong sheet of carbon paper - designs call for a ribbon "3 feet wide and barely thicker than Saran wrap" weighing only 7.5 grams per meter (!) at the earth end. For those who don't remember carbon paper: it's a lot lighter than laser printer paper.

Grandfather: this FUD comes up every time the space elevator is discussed here; please try to educate yourself about the proposal first. And take those "but it will discharge the atmosphere" cretins with you, thanks.

• Institute for Scientific Research, Inc. - Space Elevator
• LiftWatch.org
• LiftPort- The Space Elevator Company- LiftPort Group

No, they're not. The strongest SWNTs ever measured were just over 60GPa, instead of the >100 GPa (and desired >120 GPa) for a space elevator.

They're both too short and too weak currently.

You might find it surprising, then, to hear that I'm very excited about the possibility of a space elevator, despite being a lifelong atheist.

It's true that the space elevator relies on technology that doesn't exist yet. But that technology is rapidly advancing, and there have been extensive studies of the material properties of carbon nanotubes in the context of use in a space elevator. Of course, you'll have to wade through pages of Biblical references to get to the actual science, but that's something you'll just have to get used to if you want to read about space elevator technology.

In addition, a mass driver is simply NOT a substitute for a space elevator. Even if a practical electromagnetic mass driver could be built, each launch would require a large amount of energy that would never be recovered. The space elevator uses less energy to send each ton of matter to GEO than any other proposed system, but that's not the really cool part. You see, each ton of matter that is returned from GEO effectively recovers the energy required to send that matter up in the first place via regenerative braking.

This is also where I should mention that, energy concerns aside, the space elevator removes one of the largest risks from space flight - reentry. Mass drivers help you get into orbit, but they don't help you return from orbit at all. In a space elevator, though, you just press the "down" button. Simple as that.

Now, if you'll excuse me, I have to go do my religion homework. Oops, I meant to say science homework. I have such a hard time keeping those two subjects separate... but you can't really blame us clueless space elevator kooks for that, right?

The problem is, it's not very efficient, at all. It makes power beaming by laser look efficient by comparison. Dr. Bradley Edwards considered it when doing space elevator design, and came up with a best-case number of around 0.05% for total system efficiency.

then try this link for those of you who don't know what a "space elevator" is (and insist on hanging around here). It is a faq on a study done on the concept. More info is also on the site.

Here's my understanding with the space elevator. The most serious proponent these days is a guy named Bradley Edwards who came out of one of the national labs. His idea involves beaming power up to the climber from the ground:

The power for the construction and cargo climbers (100kW to 2.4 MW) is beamed up using a free-electron laser (840 nm) and 13 m diameter segmented dish with adaptive optics, identical to the one being constructed by Compower Inc. and received by GaAs photocells (80% overall efficiency at this wavelength) on the climber's underside. This power, converted to electricity, would be used by conventional, niobium-magnet DC electric motors and a set of rollers to pull the climbers up the ribbon at speeds up to 200 km/hr.

Sure, our society is dependent of fossil fuels, but we won't be running out anytime soon. We'll probably reach our peak production within a few years (where all the easy to get oil is gone), which will threaten world economies - but (hopefully) it's not the end of civilization.

Nuclear energy, and possibly fusion someday are viable options.

Your right about microwaves though, they would agitate the water vapor in the atmosphere, and while this couldn't substantialy effect global warming (compared to the millions of tons of CO2 produced every year) it would effect the local weather. More importantly though, the atmospheric heating would waste a lot of energy. Furthermore, I'm willing to bet that the distances involved would spread the beam out over a large area - requiring a large and expensive collection dish.

Transmiting the power using actual cables is outright infeasible. Not only is the distance far enough to create significant losses, but to transfer power on the scale to replace fossil fuels would require a huge bundle of cable - which will weigh many, many tons. (insert Kim Stanley Robenson doomsday wrap-around scenario here)

A much more practicle solution is the use of a Free Electron Laser (FEL) Beam to transmit power, which is exactly what the agency who conducted the Phase I research suggests.

Everything you need to know from the offical site here.

Sure, our society is dependent of fossil fuels, but we won't be running out anytime soon. We'll probably reach our peak production within a few years (where all the easy to get oil is gone), which will threaten world economies - but (hopefully) it's not the end of civilization.

Nuclear energy, and possibly fusion someday are viable options.

Your right about microwaves though, they would agitate the water vapor in the atmosphere, and while this couldn't substantialy effect global warming (compared to the millions of tons of CO2 produced every year) it would effect the local weather. More importantly though, the atmospheric heating would waste a lot of energy. Furthermore, I'm willing to bet that the distances involved would spread the beam out over a large area - requiring a large and expensive collection dish.

Transmiting the power using actual cables is outright infeasible. Not only is the distance far enough to create significant losses, but to transfer power on the scale to replace fossil fuels would require a huge bundle of cable - which will weigh many, many tons. (insert Kim Stanley Robenson doomsday wrap-around scenario here)

A much more practicle solution is the use of a Free Electron Laser (FEL) Beam to transmit power, which is exactly what the agency who conducted the Phase I research suggests.

Everything you need to know from the offical site here.

Did you read the whole page. At the bottom he says...

We would be far better off to invest the money into more advanced propulsion systems, like those aboard the non-existent (?) TR3 black triangle. Its time this drive technology was released to the masses that paid for it in the first place ! Such propulsion systems won't just get us 62,000 miles from earth, but instead to other planets.

If the government had a propulsion system like that they would use it for space launches.

Anyway the study I read said it would de-ionize an area a few centimeters around the cable, because air is not that conductive, and the Ionosphere regenerates itself.

Check out the "Challenges" page of the NIAC paper here.

It covers things like lightning, meteors, wind and other factors.

If we suddenly have 100 miles of superstrong material slamming down at hypersonic speed, it's going to be extremely bad

It'll be more like a 100-mile piece of paper fluttering to the ground. The ribbon will be extremely light. It needs to be, or it can't hold up its own weight. Why don't you go read the Space Elevator FAQ before displaying your ignorance?

Half way up, at 32,000 miles, there is no appreciable drag. Also, I question your mass-density assumptions.

Once that portion enters the earths atmosphere, however, it will begin decelerating and disintegrating and will have plenty of time to do so before it can hit objects on the ground.

Upon what are you basing your assumptions of its width and overall mass per unit of width-length?

Well, according to the documentation the nanotubes have a density lower then kevlar, and the lower portion is 2CM wide by 5 microns thick. Now, if they goop the nanotubes up with epoxy, that could affect the density by a little bit (they don't plan to use much). With just the nanotubes, we are looking at a weight of 130grams per kilometer of cable (0.02M * 0.000005M * 1000M *1300 Kg/M^3 = 0.130Kg). For comparison, I just measured a piece of reynolds heavy duty aluminum foil at around 0.5 mils (12.7 microns). So, one food service roll (18"x500foot) could be cut into 22 ribbons and welded end to end to make 3.3Km of cable (at 2-3 times the thickness) and more than twice the density (2700 Kg/M^3). So, your aluminum replica will be about 5 times as heavy and (very roughly) 1000 times weaker than 3.3Km of nanotube cable. The tensile string of the nanotubes is 130GPa (19 million psi). The entire 91000KM length of cable will weigh roughly 18000 Kg, or about as much as 20 automobiles. If 1 km of the ribbon hits you at the speed of sound the force of impact (44.2 kg m/s) would be the equivalent of a 98 pound weakling bumping into you at a slow walk (2.2mph). But you might get one hell of a paper cut.

Their worst case estimate for how long a segment of cable could fall to earth without disintegrating is about 4000km or 3000kg (about the weight of two SUVs). That density is different that what I discussed above because we are talking about a higher strength cable. It looks like the figures I was looking at were for the cable before it has been beefed up by the maintenence droids. Now, I don't want a hummer landing on my head but it doesn't sound any worse than a stray rocket.

One point that space elevator advocates always seem to conveniently forget is that carbon nanotube composites will benefit competing technologies, as well.

For example, they would make it much easier to achieve the tankage mass ratios required for a single stage to orbit reusable launch vehicle. Such vehicles are believed to be marginally possible today but CNT composites could easily make them competitive with elevators.

Jordin Kare of LLNL has a nice presentation comparing the costs of space elevators to other potential technologies. The bottom line is that the elevator is not necessarily cheaper and has much larger up-front costs before the first payload goes up.

Using space elevators as a justification for investments in CNT composite technology is propaganda.

Their FAQ says it would be a week long trip. Guess it would be traveling at about 369 mph.

Yep 62000, it's all explained in their FAQ

Have you read about what this system is like first?

I live very close to Fairmont, and have passed the Institute many times during its construction. Nothing ever really happens in WV, so its refreshing that a good idea for space exploration is coming out of this so-called "hick, backwards" state. Anyway, back to the point. I am applying for a job there after my masters is completed here at WVU, or where ever I end up. Not sure if there's a need for Math degrees, but hey, I can try, right?

Here is a link to photos of the construction.
ISR

Does this mean that we can build the Space Elevator out of mayonnaise?

From here:

Phobos's orbit is slowly decaying, spiraling in towards Mars, so that Martian tidal forces may overcome the satellite's own gravity and break Phobos up into a ring like Saturn's, perhaps within 50 million years. Deimos may, like our Moon, be slowly spiraling outward.

I'd say your news of Phobos' imminent demise is greatly exaggerated. Before that happens we'll have used it as a counterweight for a Martian space elevator anyway.

some credible third-party analysis

This is one aspect of the current NIAC Phase II study. The third conference on space elevators is coming up and should provide a venue for such discussions. This is quickly morphing from a one-man show (Brad Edwards) into a respectable research area.

Here's a link to the presentation by Jordin Kare you're thinking about: http://www.isr.us/spaceelevatorconference/pdf/Kare /Workshop2_kare.pdf. One point he makes is that, to a large degree, propellent costs are irrelevant to the economics of lifting payloads to earth orbits. Space elevators satisfy a desire for technological elegance we all share, but they don't really seem so interesting when you examine their economics.

And if you're a new fan of nanotubes, here's a potentially revolutionary application: a space elevator. Too bad about the crappy material properties of this nanotube thread. I really thought at first this might be our big break towards really affordable space travel.

The first step is to capture an asteroid

Not needed. Read the NIAC Phase I report - a space elevator could be deployed with the equivalent of 7 shuttle launches. Total cost has been estimated as low as 15B US$ - compare that to the ISS and other boondoggle programs.

The only technology required that we don't yet have is mass-production of carbon nanotube cables, and that looks like it will happen within the next couple of years.

I agree that throwing money at the problem of building a carbon nanotube cord to come close to the required strength would not be a good idea. But there are many other problems to solve. There are few risks in the construction and deployment phases. Political factors, site candidates, and power generators and delivery systems need to be invented (to name a few). These projects could be farmed out colleges and university as competitive grant awards or to companies as competitively bided contracts. In doing so, the current cost of the program would be the cost of those NASA funded grants and contracts. It could be price limited to 20 Million a year and still make an impact.

I agree that throwing money at the problem of building a carbon nanotube cord to come close to the required strength would not be a good idea. But there are many other problems to solve. There are few risks in the construction and deployment phases. Political factors, site candidates, and power generators and delivery systems need to be invented (to name a few). These projects could be farmed out colleges and university as competitive grant awards or to companies as competitively bided contracts. In doing so, the current cost of the program would be the cost of those NASA funded grants and contracts. It could be price limited to 20 Million a year and still make an impact.

I agree that throwing money at the problem of building a carbon nanotube cord to come close to the required strength would not be a good idea. But there are many other problems to solve. There are few risks in the construction and deployment phases. Political factors, site candidates, and power generators and delivery systems need to be invented (to name a few). These projects could be farmed out colleges and university as competitive grant awards or to companies as competitively bided contracts. In doing so, the current cost of the program would be the cost of those NASA funded grants and contracts. It could be price limited to 20 Million a year and still make an impact.

I agree that throwing money at the problem of building a carbon nanotube cord to come close to the required strength would not be a good idea. But there are many other problems to solve. There are few risks in the construction and deployment phases. Political factors, site candidates, and power generators and delivery systems need to be invented (to name a few). These projects could be farmed out colleges and university as competitive grant awards or to companies as competitively bided contracts. In doing so, the current cost of the program would be the cost of those NASA funded grants and contracts. It could be price limited to 20 Million a year and still make an impact.

I agree that throwing money at the problem of building a carbon nanotube cord to come close to the required strength would not be a good idea. But there are many other problems to solve. There are few risks in the construction and deployment phases. Political factors, site candidates, and power generators and delivery systems need to be invented (to name a few). These projects could be farmed out colleges and university as competitive grant awards or to companies as competitively bided contracts. In doing so, the current cost of the program would be the cost of those NASA funded grants and contracts. It could be price limited to 20 Million a year and still make an impact.

I know this is off-topic, forgive me. But it seems like a good time to bring this up.

If we are to spend hundreds of millions, maybe billions, of dollars in a multi-decade endeavor in name of science and profit, why not build a space elevator. The project isn't ready to begin yet, since we currently can't produce carbon nanotubes in sufficient quantity or quality, but with the research might of NASA and the heightened awareness of the goal we could create get a head start at the next space race. After which, the cost for all other space initiatives would be greatly reduced. The long term economic benefits of building the first space elevator could possibly outweigh the initial research and construction costs.

At the upcoming conference on the topic of space elevators, scientists will discuss the logistical, engineering, and political issues.