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The Space Elevator

timothy posted more than 11 years ago | from the long-cable-long-review dept.

Space 735

James Yonan writes "For years, the space elevator concept has been a staple of science fiction fare, popularized by Arthur C. Clark in The Fountains of Paradise, a convenient and plausibly feasible technology for building a vertical railroad of sorts, tens of thousands of kilometers tall, linking earth with geosynchronous orbit. Unsatisfied with the unquestioning consignment of the space elevator concept to science fiction status, authors Bradley C. Edwards and Eric A. Westling set out to understand why it could or couldn't be done. The result is a compelling new book, backed up by voluminous research, which concludes that space elevators are near-term-feasible. Edwards and Westling have not only convinced roomfuls of skeptics of the basic concept, but have also won serious funding from NASA for continuing their work. This book, The Space Elevator, is one of the fruits of their ongoing research." This is a long review (continued below), but the subject demands it.

As a child in the late 60s and early 70s, some of my earliest memories are TV images of the moon shots, the sense of excitement and adventure, and confident assertions by adults that this was only the beginning, that progress was indeed unstoppable, and that it was a near certainty that by the time I was old enough to ask a girl out on a date, the question "would you like a ride in my spaceship" would be greeted not with derision, but with awe. Of course the sad reality is that none of this has come to pass. Space has remained dangerous, expensive, and inaccessible to all except the rare test pilot, scientist, or those for whom capitalism has been unusually kind. Luckily, there are some promising new ideas in space transportation that could represent the breakthrough we have been waiting for in the years since walking on the moon became passé.

In their new book The Space Elevator, Bradley C. Edwards and Eric A. Westling present a compelling argument, backed up with a great deal of quantitative analysis on both scientific and economic grounds, that a space elevator is near-term-feasible. The authors argue that carbon nanotube fibers are both strong and light enough that a 100,000 km elevator, constructed of a 2m wide carbon nanotube "ribbon," could be constructed in 10 years for a cost of US $6 billion, and be capable of lifting a 13-ton payload to geosynchronous orbit once every few days. If feasible, it would present a stunning breakthrough in space accessibility, and likely usher in a new age of space development and exploration.

Edwards writes in the forward:

One day, a few years ago, I read a statement that the space elevator couldn't be done, and I set out to find out why. From there, things got very interesting and resulted in a research proposal being submitted to NASA. The proposal was funded and resulted in, first a six-month study and then a two year study. The core of this manuscript started out as the technical report from the six month investigation I conducted for NASA under the NASA Institute for Advanced Concepts (NIAC) program.

Edwards and Westling begin the book with some history. Until recently, it was thought that alternatives to chemical rockets as a means to reaching LEO (low Earth orbit) were, at least for the foreseeable future, the stuff of science fiction. The idea of a space elevator, foreseen as early as 1903 by the brilliant Russian science speculator Konstantin Tsiolkovsky, foresaw a tower to geosynchronous orbit and beyond.

He was the first to identify the concept that the part of the tower beyond geosynchronous orbit would have an outward "force" due to Earth's rotation that would support the portion of the tower below geosynchronous altitude.

Essentially a space elevator is a geosynchronous satellite with an unusually high aspect ratio. So high, in fact, that even though the satellite is in orbit over a fixed point on the Earth's surface, the lower portion of the satellite actually touches the surface of the Earth. The key, of course, to making this concept workable is to find a material that has the tensile strength to withstand the extreme forces that such a tower or cable would be subjected to. Though a space elevator would need to reach 35,785 km to geosynchronous orbit, since gravity drops off as the square of our distance from Earth, we can collapse the 35,785 km down to its equivalent height as if it were all in 1g, giving 4940 km. This magic number represents the self-support height that a space elevator cable would need to exceed. The self-support height is the maximum length of material, formed into a cable, that can support its own weight in a 1g gravity field before breaking, and can be calculated by dividing tensile strength by density.

It turns out that a steel cable has a self-support length of 54 km, graphite whiskers (fibers) 1050 km, and carbon nanotubes 10,204 km. This last figure is an important result that shows that carbon nanotubes are significantly stronger than would be needed to build a space elevator. The difference between the 4940 km minimum self-support length and the carbon nanotube self-support length of 10,204 km all translates into significant payloads that could be lifted into space using this technology.

So if the space elevator is feasible right now for only US$6 billion (less than half of NASA's annual budget), why aren't we building one ASAP and preparing to retire the shuttles? The answer is that carbon nanotube technology is so new (invented in 1991) that we haven't yet created the infrastructure for mass production. In fact, the authors admit that we haven't even created a nanotube in the lab that demonstrates the requisite strength. While carbon nanotubes have a theoretical tensile strength of 300 GPa (billion newtons per square meter), strengths of only 11.2 to 64.3 GPa have been experimentally measured thus far. Edwards and Westling have heavily based their thesis on nanotubes reaching a tensile strength of 130 GPa in mass-produced volume, so they are to some extent reaching for the future here. Clearly they are counting on a kind of Moore's law to kick in, where the efficiency to cost curve of nanotube production improves exponentially as breakthroughs are made, then asymptotically slows as the theoretical upper bound is approached.

Now assuming that we can economically mass produce carbon nanotube ribbon at a strength of 130 GPa, what's next? Here Edwards and Westling present a well-researched plan for turning the raw material of the carbon nanotube into a functioning space elevator within 10 years. An initial kind of bootstrap cable would be lifted into LEO on board several trips of the space shuttle. This cable would be constructed of carbon nanotubes arranged in parallel with a reinforcing cross-connect adhesive, so that if a nanotube was severed, the remaining tubes would take up the load. The cross sectional dimensions of the cable would be highly asymmetrical, 1 micron in thickness, 13.5 to 35.5 centimeters in width, hence the cable is referred to as a "ribbon". After some assembly in LEO, the initial ribbon and deployment mechanism would be integrated into a spacecraft and sent to geosynchronous orbit, where it would deploy by basically unwinding the spool of ribbon towards Earth, while the spacecraft-spool assembly itself is boosted higher to maintain the total system in geosynchronous orbit. Once a few km of ribbon is unspooled, gravity gradient forces will kick in, ensuring a stable vertical orientation as deployment proceeds. Eventually the end of the ribbon would reach Earth where it would be anchored to a mobile sea-platform, located near the equator, which would have the capability to move the lower end of the cable to dodge known space-junk and electrical storms.

This prototype space elevator will be relatively weak and vulnerable to damage from meteoroids and uncharted space junk, so it will be essential to quickly strengthen the ribbon by widening it. Edwards and Westling's plan calls for "climbers" (electric-powered vehicles that climb the ribbon using a mechanical traction drive) to immediately ascend the ribbon, splicing additional carbon nanotube material onto the existing ribbon, then permanently parking at the far end of the ribbon to add to the elevator's counterweight mass. After 230 iterations of this process, the ribbon will be complete, 2m wide and capable of lifting 20 tons of climber + payload.

Getting a 100,000 km space elevator into position and insuring its survival is a daunting engineering challenge, and much of the book is dedicated to answering what-if scenarios and attempting to prove to the skeptical mind that such an ambitious undertaking is feasible. To this end, each space elevator subsystem is analyzed at length and competing solutions are evaluated for cost and efficiency.

For example three different methods for supplying electrical power to the climbers are evaluated:

  • run power up the cable,
  • beam power via microwave, and
  • beam power via laser.

Answer: use a laser.

An optimal shape (i.e. taper profile) for the ribbon is proposed, so that the part of the ribbon in the atmosphere is narrow to minimize wind-loading forces and the section between 500km and 1700km is widened and slightly curved to maximize survivability from meteoroid or space junk impacts. The destructive effects of wind, lightning, atomic oxygen, debris impacts, radiation damage, and ribbon oscillations are considered and solutions are presented. The conclusion: none of these adverse effects are show-stoppers.

Some basic FAQs are presented and answered, such as where does the energy come from to accelerate a climbing payload on the ribbon to orbital velocity. Answer: from the rotational inertia of the planet. If we shipped a whole continent into space, our days would get a bit longer.

After a comprehensive technical and engineering analysis of the space elevator concept, the authors move on to the economics of the concept and present a sort of skeletal business plan for "Space Elevator, Inc." They present many interesting uses for the space elevator including energy applications that could significantly improve the environment and reduce the combustion of fossil fuels. If the space elevator succeeded in reducing launch costs below $100/kg, large orbiting photovoltaic arrays might be built in space that would collect power and beam it to Earth via microwaves. These ideas are far from new (such an apparatus was patented in the early 1970s), but the reduced launch costs of the space elevator make them far more feasible.

The authors take a detour in explaining some promising results on the nuclear fusion front. Progress on the reduced-radiation IEF concept (Inertial Electrostatic Fusion) for fusion reactors would be accelerated by 3HE mining on the moon, which the space elevator would make feasible.

The rationale for building the ribbon up to 100,000 km is examined. The major advantage of such a tall ribbon is that the centripetal acceleration of the ribbon tip is substantial enough that payloads could be flung to Venus, Mars, or the asteroid belt with little additional energy expenditure. This, the authors argue, would bring down the cost of robotic planetary probes to the point where individual universities could afford their own space programs.

And finally, a working space elevator can be used to manufacture new space elevators at a much lower cost than the initial implementation. The authors suggest that the first significant commercial application of the space elevator might simply be in making additional space elevators and selling them to commercial clients. In this manner, elevators with payload capacities up to 200 tons could be deployed using wider ribbons, making possible a large-scale human presence at geosynchronous orbit and bringing the kind of commercial activities that would go along with that, such as tourism.

The book ends with a flight of fancy of sorts into a future where space elevators have become commonplace. Space elevators around Mars create an efficient Earth-Mars transportation network. Elevators on the moons of Jupiter throw spacecraft down into Jupiter's turbulent upper atmosphere to scoop up 3HE and ship it back to Earth in decade-long space convoys where it will power the latest and greatest IEF fusion power-plants.

While The Space Elevator goes a long way towards convincing skeptics of the feasibility of the general idea, the big question marks that remain in my mind are:

  • Will carbon nanotubes really reach the 130 GPa level in cost-effective mass production that will be required for elevator construction?
  • Much of the elevator deployment plans depend on the flawless execution of robotic mechanisms controlled remotely from Earth, including the trip from LEO to geostationary orbit, the deployment down to Earth, and the subsequent strengthening of the ribbon by robotic climbers that splice additional nanotube material onto the existing ribbon. As we learned with the Hubble Space Telescope, it is essential to have astronaut access for unexpected but critical repair missions. But much of the space elevator deployment will take place above LEO, out of access of human shuttle missions. What do we do if there is a glitch during deployment that requires an astronaut repair? We will need to seriously address such contingencies, lest we get saddled with a stuck elevator that could become the mother of all space junk.
  • Have there been any successful tether missions to date in space? While the answer appears to be yes, I would have liked to learn more about them.

Doubts aside, this is a compelling work that will likely become both a manifesto and bible for the space elevator movement, presenting a convincing argument that the space elevator is our best chance yet to bring Moore's law economies to space. It is an engaging read and I highly recommend it.

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Bone-O-Rama (-1)

cyborg_monkey (150790) | more than 11 years ago | (#5449053)

Strikes again. Damn, I am the best FP'er EVAR!

read Pratchett (4, Funny)

boogy nightmare (207669) | more than 11 years ago | (#5449056)

Read Terry Pratchett's Science of Discworld books for more information on this......

Read Kim Stanley Robinson (2, Informative)

Robotz (451860) | more than 11 years ago | (#5449154)

There are a series of SF books by Kim Stanley Robinson, titled Red Mars, Green Mars and Blue Mars.

Space elevators are part of the story, and the sabotage of a space elevator on Mars results in catastrophe. I recall that the sabotage involved the cable being detached from the space station end. The space station flew off into space, and the cable fell back to ground, wrapping itself around the planet's equator.

Muzak (5, Funny)

govtcheez (524087) | more than 11 years ago | (#5449060)

Good Lord - the amount of Muzak one would have to listen to on the trip to the moon should be enough to stop a project like this in its tracks!

Re:Muzak (1)

dubbayu_d_40 (622643) | more than 11 years ago | (#5449137)

No, Space Muzak...

heartsofspace dot com

Re: Muzak (1)

Black Parrot (19622) | more than 11 years ago | (#5449150)

> Good Lord - the amount of Muzak one would have to listen to on the trip to the moon should be enough to stop a project like this in its tracks!

Red Dwarf occasionally makes a good joke about this, though it's usually about watching an advertising movie rather than listening to the "elevator" music.

NASA: "Need Another Seven Astronauts" (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5449063)

Shortly after the Challenger disaster on January 28, 1986, a sick joke started circulating. NASA was reported to mean, "Need Another Seven Astronauts."

Unfortunately, as news reports come in about disregard for safety for Shuttle Columbia, it appears that such joke has a major element of truth. NASA bureaucrats (and probably politicians up to and including at the White House, as well) disregarded Morton Thiokol engineers in 1986, and we're now hearing that engineers warned NASA officials and the President prior to Columbia's launch that the Shuttle system itself was prone to such a disaster as witnessed yesterday. We know that Columbia was hit with "something" ("foam" or more likely, ice) during its launch on January 16th, and apparently, officials didn't take it seriously enough (Cain slew Abel; did Leroy Cain slay Columbia?). The excuse that "Columbia's crew was doomed from the start because they couldn't make repairs" is both silly and illustrates the current "can't do" attitude of today's NASA, which is far different than the NASA which both put humans on the Moon AND safely returned a crew to Earth after Apollo 13 had a "major malfunction" way up there.

For NASA's bureaucrats (and some politicians), it appears that risking astronauts' lives, NOT for the "unknown variables," but for glamour, expediency, and selfishness, is "acceptable." Perhaps this is to be expected in today's America where style and appearance are far more valued than substance and tangibility.

The joke way back in 1986, "N.A.S.A. = Need Another Seven Astronauts," has tragically turned out to be 2003's reality.

Great review... (3, Funny)

Ratface (21117) | more than 11 years ago | (#5449064)

... now I don't need to buy the book!

Honestly, that was more of a synopsis than a review dont'cha think??

Re:Great review... (1)

Mr2cents (323101) | more than 11 years ago | (#5449219)

Well, they don't tell you how it ends, do they?

Why take a space elevator (1, Funny)

ReidMaynard (161608) | more than 11 years ago | (#5449066)

when my flying car will get me there faster?

Plot. (5, Funny)

grub (11606) | more than 11 years ago | (#5449073)

The whole space elevator thing is a conspiracy being run by The Illuminati. They plan to run wires up within the elevator shaft providing an unparalleled antenna for their mind control rays. At the top they are going to have a lounge and war room from which they can watch their world and plan our lives.

Call me paranoid all you want, but it's about time the trut... oh just a sec, there's someone at my door...

Re:Plot. (0)

Anonymous Coward | more than 11 years ago | (#5449295)

I no longer reply to chickenshit ACs and suggest you do the same.

Why not?

Pie-in-the-sky nonsense (2, Funny)

Anonymous Coward | more than 11 years ago | (#5449077)

Now assuming that we can economically mass produce carbon nanotube ribbon at a strength of 130 GPa, what's next?
Assuming that, it remains only to corral the unicorn, saddle up our flying pig and blast off! In-flight entertainment: Duke Nukem Forever.

dangerous?? (3, Insightful)

in_ur_face (177250) | more than 11 years ago | (#5449078)

ok, so what if this damn thing falls??

I dont know about you guys, but the whole concept seems flawed from the start. How about maintenance? What if the payload falls? I dont want to live anywhere near this thing....

Re:dangerous?? (5, Funny)

Anonymous Coward | more than 11 years ago | (#5449106)

If it falls, blame it on an oil-rich nation and invade. Duh.

Re:dangerous?? (5, Insightful)

mrtroy (640746) | more than 11 years ago | (#5449113)

they plan on anchoring it off the coast of australia (or apparently thats a good spot for it) (i dont know why)

and also apparently due to the forces acting on it if it did "fall" or break it would go flying off into space instead of collapsing on earth

keep in mind how fast the earth is spinning! if you spin a basketball with a straw attached to it and the straw gets unstuck from the basketball...where will the straw go? It sure wont collapse onto the ball.

Re:dangerous?? (1)

mark-t (151149) | more than 11 years ago | (#5449128)

If you don't want to live near it, either you better hope it never gets built or you'll have to find another planet to live on, because for something of that size, the whole friggen planet is "near" it.

Re:dangerous?? (4, Informative)

krugdm (322700) | more than 11 years ago | (#5449133)

I seem to recall that the base of these things would be on large platforms anchored in the middle of the ocean, so if they did collapse, they would just fall harmlessly over water.

Re:dangerous?? (1)

GeckoX (259575) | more than 11 years ago | (#5449281)

Yeah, but we can't even keep drilling platforms stable enough to survive violent storms...fat chance in hell I say.

Also, the first one would deffinately be over water...but say the first few work just fine for the first little while, and we get lax and 20 years from now every major urban centre has one...and shit happens...

Don't want to be there.

Re:dangerous?? (4, Insightful)

RedCard (302122) | more than 11 years ago | (#5449151)

That's what they said about the eiffel tower, the CN tower, the first skyscrapers...

Re:dangerous?? (0)

Anonymous Coward | more than 11 years ago | (#5449181)

Yeah, no-one's ever been killed in a falling skyscraper, have they.

Re:dangerous?? (1)

Azghoul (25786) | more than 11 years ago | (#5449174)

Considering the proposed placement of such an elevator (out attached to a floating platform in the Pacific), I doubt you'll have to live near it, at least until the undersea tubes and biodomes are complete.

Re:dangerous?? (5, Informative)

Anonymous Coward | more than 11 years ago | (#5449202)

read the initial feasability report. it (mostly) disintegrates as it falls to earth ia c_pdf/chapter10.html#impact

Re:dangerous?? (3, Informative)

Vengeance (46019) | more than 11 years ago | (#5449238)

Go check out the FAQ at High Lift Systems [] and see for yourself. It's not THAT much of a concern, because it's really a satellite, and wouldn't break orbit. The tricky bit is whatever is below the break, particularly payloads. The intended ribbon itself is incredibly light-weight, only 7.5 kg/km, and thus won't cause ridiculous amounts of damage.

Not Dangerous (Mostly) (4, Insightful)

Inexile2002 (540368) | more than 11 years ago | (#5449266)

Unless you're pretty much standing underneath it.

This is one of those mass to surface area things. Although it would be freaking huge, if something happened which caused part of it to come down (which isn't what would happen, most would just sit there in space or drift away) it wouldn't be like a building collapse in one place.

It would come down in pieces and most of the higher up junk would disintegrate. The stuff that was low enough not to disintegrate on re-entry would constitute a fraction of the mass and would come down in pieces scattered over a wide area of ocean. People at the base might have a really bad day but if you were not actually at the base facility you'd be in just as much danger as people were when Mir came down - ie not much.

It's easy to get alarmed at the thought of the biggest structure of all time falling to the earth but in terms of actual danger to human beings the average sky scraper or speeding train presents a much bigger risk.

As for falling payload, unless the payload was designed to survive re-entry and maybe fitted with a targetting system (which sadly is entirely possible) no one would be in any real danger. I mean, there is ALWAYS the possibility that something will fall from space and land on you, but if you're going to spend your time worrying about that you real problem is paranoia. You're hundreds of thousands of times more likely to die by slipping in the tub.

Re:dangerous?? (1)

Niles_Stonne (105949) | more than 11 years ago | (#5449296)

Take a look at This Study [] That issue is covered.

Take a look at section 10.9.1, page 64 of the PDF, which covers the "Severed Cable" issue in particular.

why not construct this (5, Insightful)

mrtroy (640746) | more than 11 years ago | (#5449083)

Why does Bush not say that his goal for America is to construct this during this decade? (similar to JFK, etc)
This time in our history will be looked back at for terrorism, war, and world diplomatic struggles. Why not unite and construct something of this magnitude to unite us all? I am sure the terrorist strikes will stop themselves if the US gains a reputation for a R&D and science nation instead of a warring and military nation. If the U.S. put a 6 month hold on current military spending on new aircraft/ships/etc they could afford this construction 10 times over.

Re:why not construct this (2, Interesting)

Anonymous Coward | more than 11 years ago | (#5449100)

Sounds like someone's already been takin' the space elevator...pretty early in the morning, no less!

Anyway, everyone knows that the real reason that NASA got so much money was to beat the Commies. It WAS military spending.

Re:why not construct this (2, Insightful)

in_ur_face (177250) | more than 11 years ago | (#5449101)

"I am sure the terrorist strikes will stop themselves if the US gains a reputation for a R&D and science nation instead of a warring and military nation."

i'd be worried of the terrorits flying planes into the space elevator :(

Re:why not construct this (0)

Anonymous Coward | more than 11 years ago | (#5449120)


Because its a reckless and unfeasible idea.

Seriously. It looks good on paper. But it's not going to happen, not any time soon. It requires the invention of materials that dont really exist (carbon nanotubes and whatnot).

BTW, the US already has the reputation as an "R&D and science nation". They put the man on the moon, remember? They invented the airplane and the automobile. They harnessed electricity, developed the computer and then the internet.

Re:why not construct this (1)

mrtroy (640746) | more than 11 years ago | (#5449245)

I am not saying that America does not spend on research and development.

I am simply saying you spend far more on military equipment.

Hence, you gain the reputation as a military nation.

Re:why not construct this (2, Informative)

FreeLinux (555387) | more than 11 years ago | (#5449152)

Why does Bush not say that his goal for America is to construct this during this decade?

Well, to put it simply, he's not a complete and utter moron! Please, don't compare this space elevator lunacy with JFK. JFK proposed a difficult but doable task that was definitely within the nations technical capability. The space elevator is only feesible in the minds of those who have read TOO MUCH Heinlein.

Re:why not construct this (4, Insightful)

wind (94988) | more than 11 years ago | (#5449208)

I can't quite tell if you're serious with this comment... I don't think anger with the US will evaporate just because we stop trying to tell everyone what to do...


Why does Bush not say that his goal for America is to construct this during this decade? (similar to JFK, etc)

Because, despite his claims that he is a"unificator" and not a "divider-upper", Bush does not appear to have any real interest in "unificating" with other countries except to further US power. I know some (US) people will undoubtedly say that this is far better than working with other countries to weaken US power, but nonetheless, I can't imagine why someone who appears to have nearly no interest in domestic issues - let alone scientific research - would make this a funding priority.

Unless someone could convince him that this could revive that whole SDI "Star Wars" thing...

Re:why not construct this (0, Flamebait)

mrtroy (640746) | more than 11 years ago | (#5449268)

You elected him...
Was there a lot of terrorist activity against the US during the space race?

And the world would be much happier if the US stopped trying to run every other country...
:) I know I would be. Luckily you have not bothered us too much.

Re:why not construct this (0, Offtopic)

(trb001) (224998) | more than 11 years ago | (#5449250)

I am sure the terrorist strikes will stop themselves if the US gains a reputation for a R&D

One of the principle reasons that the Islamic terrorist groups despise the US is because we've walked away from the 'Religious Path' that they follow...I'm a Christian and therefore not really in touch with the Koran or any other Islamic doctrine, but I'm imagining that an elevator 'reaching into the heavens' could be seen as a threat to their beliefs.

No matter what the US does, some well funded group will not like this idea and try to destroy it. That is, unfortunately, human nature.


Re:why not construct this (2, Insightful)

mrtroy (640746) | more than 11 years ago | (#5449297)

I have not known Islamic terrorist groups to attack Canada

The majority of Canadians are Christian.

So, despite that being a "reason", i see it as more of an excuse...

Wow... a Review! (3, Insightful)

sielwolf (246764) | more than 11 years ago | (#5449088)

This is probably more of a book review than what /. has been subjected to in a long time. It didn't feel like reading a 500 word essay that ended with "it was very very very very good."

Of course there was less "review" and more "synopsis" than I would like. But then expecting the author to provide interesting critique might be a bit much. Overall much better than other reviews we've had.

Re:Wow... a Review! (5, Insightful)

Jerf (17166) | more than 11 years ago | (#5449210)

Of course there was less "review" and more "synopsis" than I would like.

Different types of writing require different types of review. The type of "review" you seem to be asking for is really only appropriate for fiction. For a book of fact, the questions to answer are:

1. What was the main point of the book? (Yes, that's a "synopsis". That's part of reviewing non-fiction.)

2. How well did the authors justify that point?

This review answers both those questions. Because the answer to number 2 is "quite well", that is relatively short, as it should be. It is much easier, and much more interesting, to list shortcomings then to list correct things. Are you really asking for them to write "All footnotes were written to modern standards. The title page was well-laid out and included correct Library of Congress information. Footnotes were correctly presented in 10pt font. The table of contents was complete and correct. The page numbers were correct."? These are things you assume until you have reason to believe otherwise.

The answer to number 1 is importent in deciding whether you want to read the book or not, which is the final purpose of the review. In lieu of a lot of #2 to discuss, it should typically make up the bulk of the review for non-fiction.

For a fiction review, it makes much more sense to talk about the intangibles, like style, characterization, and "relevance to the reader" or "the times". For a non-fiction book, it makes much less sense to spend much time on it unless it is either superb or atrocious.

This review was fully appropriate to the book, and should be commended as such. Cynical observations that all reviews on Slashdot have looked like that, and this time it just happens to fit that subject matter, are left to the reader; I'll extend the author the benefit of the doubt. ;-)

Re:Wow... a Review! (1, Funny)

Anonymous Coward | more than 11 years ago | (#5449220)

Dear sielwolf,

Your review of the review was insightful. It was helpful to read your 394 word essay that ended by telling us that the review as very very very very good. I look forward to your future review reviews.

- Captain Chaos

The obvious question (1, Redundant)

Kiwi (5214) | more than 11 years ago | (#5449089)

The obvious question is this: How do we prevent a major diastar should the space elevator ever break? This is my one misgiving with a Space elevator: Should it ever break, you will have a ultra-strong cable thousands of kilometers long hitting the Earth. Think Deep Impact.

- Sam

Re:The obvious question (3, Interesting)

CommieLib (468883) | more than 11 years ago | (#5449177)

Yeah, but what's the mass? Not giga-tons certainly, And as the Earth rotates, it seems to me that it will just kind of gently lay itself down. I suppose it depends on where the cable breaks...nothing like a Deep Impact

Keep in mind that (it seems to me) the portion of the cable above the break will float up rather than falling down; the tether is as anchored to the Earth as it is suspended in space. Furthermore, it seems that this station will necessarily be situated in the middle of deep blue nowhere (because of air traffic control considerations), so whether we're talking about Ecuador or the Outback, the cable crashing slowly down is probably only a financial disaster.

I think the main problem would be security. This cable would be a monument to humanity, and hence a prime target for terrorists.

Re:The obvious question (1)

mrtroy (640746) | more than 11 years ago | (#5449226)

its a micron thick.
are YOU afraid of a micron?

Re:The obvious question (1)

kinnell (607819) | more than 11 years ago | (#5449228)

The obvious question is this: How do we prevent a major diastar should the space elevator ever break? This is my one misgiving with a Space elevator: Should it ever break, you will have a ultra-strong cable thousands of kilometers long hitting the Earth. Think Deep Impact.

The cable is under tension, so if it snaps, it will slowly drift off into space (hopefully with no one aboard). The only real problem with this kind of scenario would be the insurance claim.

Re:The obvious question (4, Insightful)

jms (11418) | more than 11 years ago | (#5449236)

Ok, I'll take a stab at it.

If it were to break, it would split into two parts, each of which would either fall straight down or drift off into space. Remember, this thing is standing still relative to the earth's surface.

If it were over the ocean as planned, the results would be a very unusual new reef.

Depending on how long it took to descend, it would be dragged around by the weather, but it wouldn't go whipping around the earth at thousands of miles per hour, wrecking everything in its path.

Re:The obvious question (1)

The G (7787) | more than 11 years ago | (#5449257)

The obvious solution would be to embed small explosives in the cable with devices to trigger them on any loss of tension. Then if the cable were cut at the top, *poof*, all you'd have to worry about is falling charcoal. The Red Mars space elevator cataclysm was a matter of poor planning, not an intrinsic flaw. (Of course, cutting the cable near the bottom isn't a threat to earth anyway, since the whole mess would just fly off into space)

Moreover, after you've built the space elevator once, building a few dozen backups would be trivial and cheap, since you could run the new "starter" cables up the existing cable.

A well-designed space elevator system could be entirely terrorism-proof.

Fix the current technology first (5, Funny)

fobbman (131816) | more than 11 years ago | (#5449094)

Please, someone work on a good ventilation system for current elevators. Riding in an elevator with a woman with really strong perfume is bad, but when she gets off of the elevator and leaves you in there alone, and then two floors later someone else gets on and thinks that it is YOUR geeky butt smelling like that, it can be traumatic.

Not this this has ever happened to be before...

it strikes me... (1)

op51n (544058) | more than 11 years ago | (#5449096)

That the idea for putting power up to the station with a laser is one possibility, but how about getting the runner up, or even launching craft in this method. We've all seen the Convex disc which is fired into the air with a laser, but the problem is it going off course slightly and thus not being properlled anymore. But if it was held to the cable, it would be in place al the way up. This could get something up in a fraction of the time/cost it would take with conventional methods, and could also be used to propell things from the end of the cable at great enough speeds to reach other places. Imagine firing a satellite off into the depths of space without the rockets, from the ground.

Climbers - problem (2, Interesting)

briancnorton (586947) | more than 11 years ago | (#5449097)

I have admittedly not read the book, but how exactly do the climbers get the material to splice onto the ribbon? Dragging up 100,000 km of CNT material seems really heavy, even if it is just a micron thick. Even if the ribbon can handle it, I have a hard time seeing a crawler that could carry that much.

Previous Space Elevator Coverage (5, Informative)

Niles_Stonne (105949) | more than 11 years ago | (#5449099)

I think that the Space Elevator is a really good idea, and there have been some very interesting(and detailed) studies of the feasibility.

Previous Articles:
Space Elevators: Low Cost Ticket to GEO? []

More on Space Elevators []

Going Up? []

Calling the Space Elevator []

Space Elevator May Become Reality [] - The Linked Study(PDF) [] Was fascinating.

Space Elevator Could Cost Less Than You Thought []

Stepping Closer To The Space Elevator []

I want to walk into an elevator some day and see two buttons - "G" and "O". (Ground and Orbit)

Do they cover what happens (2, Interesting)

Matey-O (518004) | more than 11 years ago | (#5449104)

When a suicide bomber sets himself* off at 45,000 feet?

* = and it invairably seems to be a 'him', I think women are just genetically smarter that way.

Re:Do they cover what happens (0)

Anonymous Coward | more than 11 years ago | (#5449172)

>> I think women are just genetically smarter that way

No, there are plenty of women ready to become martyrs. Thing is, islamic law says they are inferior and purile, and dont deserve the honor of being able to kill themselves for their religion.

Re:Do they cover what happens (1)

jiggity (168453) | more than 11 years ago | (#5449199)

* = and it invairably seems to be a 'him', I think women are just genetically smarter that way.

This woman must have bad genes:

Woman suicide bomber strikes []

Female Suicide Bomber (OT) (1)

PaxTech (103481) | more than 11 years ago | (#5449294) invairably seems to be a 'him', I think women are just genetically smarter that way.

A Woman's Touch: A Female Suicide Bomber Challenges Our Preconception of the Macho Killer [] .

Actually, to stay on topic, it would probably be women who'd be against what amounts to building a giant penis for Earth to shoot our assorted junk off the earth and into space.. Can't we make a vagina shaped space elevator instead? ;)

Amazing!!!!! (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5449108)

I am positively amazed!

I'm amazed that, I am still surprised that this crap gets posted on the front page of Slashdot.

You'd think I would have learned by now....

NASA *is* funding this already (5, Informative)

DavidpFitz (136265) | more than 11 years ago | (#5449109)

If the space elevator is feasible right now for only US$6 billion (less than half of NASA's annual budget), why aren't we building one ASAP and preparing to retire the shuttles?

NASA already is funding this kind of research. They have already invested $600,000 into Seattle-based company High Lift Systems [] , according to a BBC article. []

Sounds to me the right thing to do -- invest in other companies to do the ground work, and see if it really is viable. If not they go bust -- Oh well. If it goes well, then great!

This would be a bigger target ... (1, Redundant)

SwedishChef (69313) | more than 11 years ago | (#5449112)

than the World Trade Center. Imagine planeloads of terrorists and religious extremists trying to make their point by colliding with the "elevator". Heck, for that matter imagine some unwitting student pilot in a Cessna.

Re:This would be a bigger target ... (0)

Anonymous Coward | more than 11 years ago | (#5449283)

Perhaps a no-fly zone?

Re:This would be a bigger target ... (0)

Anonymous Coward | more than 11 years ago | (#5449290)

Silly boy. It would slice the plane neatly in half. Elevator 1, Terrorists 0. :-)

moron jumping around (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5449116)

hey robbIE, we were just getting started on that last storIE. what's going on here?

it looks like the PostBlock(tm) device, is failing miserabully.

more storIEs?

Interesting (1)

RedWolves2 (84305) | more than 11 years ago | (#5449117)

I know this subject has been cover before on slashdot. I think the idea is awesome. Of course I can't figure out how this all works I assume that the tip of the elevator would have to be massive and be travelling pretty fast. It would eventually sink back down to Earth just like the ISS does (it needs a boost back up every now and then).

Maybe this sounds like a great book to understand all that. I might just go pick one up here [] .

Viscous Drag? (1)

Chembryl (596546) | more than 11 years ago | (#5449119)

No matter how strong the cable is, movement in the atmosphere (ie wind) will cause an extreme amount of drag on any such space elevator. Without a continuously replenished propulsion system at the top of the elevator, the tether will not stay taught and the satellite will fall to earth.

How exactly do you supply the amount of fuel required to something like this at the rate required? Do we even have propulsion systems able to generate a fraction of the amount of thrust needed?

Another good reason to reach for this (5, Interesting)

Jerf (17166) | more than 11 years ago | (#5449123)

The good reason to reach for this which can't be emphasized enough in the current environment is that for a relatively modest investment, the impact on the economy would be enormous (and good). Compared to other proposals to jumpstart the economy, this one has incredible bang for the buck.

Obviously this isn't a short-term, instantaneous fix, but this is exactly the sort of project that something like the United States should undertake to help maintain its lead in the economy, if it is interested in maintaining it. The economic advantage of having the only working space elevator (even if it was only until we could build another for someone else, assuming optimistically we wouldn't build ourselves a few backups first) in the world would be absolutely incredible.

Considering the price, it's complete foolishness not to pursue this, even if common sense says the opposite. And the best news of all is that carbon nanotube research is interesting enough on other, more commonly-sensible grounds, that it's going to continue anyhow.

Another thing that should be emphasized is "Suppose China gets there first." Personally, I'd love to see a space race over this issue. It would be one hell of a lot more productive over the long term then the moon race was!

Shouldn't we be working... (1)

Black Parrot (19622) | more than 11 years ago | (#5449126)

...on getting our flying cars first?

The name's Clarke, Arthur C. Clarke. (-1, Troll)

Anonymous Coward | more than 11 years ago | (#5449135)

Like in Clarke Kent.

Undefendable (1)

dfn5 (524972) | more than 11 years ago | (#5449139)

Even if the space elevator could be built, how would one defend it against terrorism. It would be kind of a big target at 22,241 miles high.

One possible practical application? (2, Interesting)

mark-t (151149) | more than 11 years ago | (#5449147)

Although it would require many, many tons of payload delivered into space each day...

Getting rid of our garbage -- do you know how much cleaner cities could be if we could just send garbage to the sun???

Re:One possible practical application? (0)

Anonymous Coward | more than 11 years ago | (#5449166)

>do you know how much cleaner cities could be if we could just send garbage to the sun?

Dude, they tried it in Futurama, and the garbage meteor just fell back to earth centuries later, after missing the sun's orbit the first time around.

Re:One possible practical application? (0)

Anonymous Coward | more than 11 years ago | (#5449204)

So you bounce it away with another giant ball of garbage.

Think about this. (1)

FreeLinux (555387) | more than 11 years ago | (#5449265)

The earth is a closed system. Our garbage, though it may be destroying the *present* environment, is an important part of that closed system. Removing significant amounts of almost anything, even garbage, from the earth will have a far greater and worse effect on mother nature than anything else we have done so far.

Right now, we may be killing our environment with our garbage. But, after we are gone the earth will continue. If we remove significant amounts of anything from the earth, it will likely die and be like the moon.

Great review. (2, Funny)

Hack'n'Slash (3463) | more than 11 years ago | (#5449153)

So good, in fact, that I don't need to read the book. Thanks James! :)

Re:Great review. (1)

Hack'n'Slash (3463) | more than 11 years ago | (#5449169)

Dang, I missed d=5449064 so now I'm going to get a -1 redundant. Oh well, I guess I'm not as funny and original as I thought I was.

Weight of the elevator? (1)

binaryDigit (557647) | more than 11 years ago | (#5449156)

Newby question here (IANAPhysicist), but wouldn't the elevator be a heavy load on the satellite supporting it? Wouldn't it exert a force downward towards the earth, thereby forcing it to continuously pull up to counter that force?

Re:Weight of the elevator? (2, Insightful)

CommieLib (468883) | more than 11 years ago | (#5449224)

I think you have to place a counterweight past (at? IANAPhysicist either) the geosynchronous point.

Re:Weight of the elevator? (0)

Anonymous Coward | more than 11 years ago | (#5449241)

the force that counters that is the centripetal force like in the roler coaster where you are spun toward the edge.

SENEGAL - home of the flying toilet (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5449157)

SENEGAL - Martha Njoki jumped when she heard a thud on the corrugated iron roof of her shack.

Seconds later, she was confronted with a familiar sight.

"I heard a bang on the roof, and when I went outside to look, I saw it was a plastic bag full of human waste," she said, gesturing towards her dwelling in the slums of Nairobi.

"You might just be relaxing in your house, then you hear a noise on your roof and someone has thrown a bag of sewage up there," said Njoki, 27, wrinkling her nose with disgust.

There are only five toilets for the more than 2,000 people living in the slum known as "Ghetto" - a fetid labyrinth of claustrophobic dirt lanes and streams of stinking effluent.

For most people here, the "flying toilets" are the only way of answering nature's call: you simply use a plastic bag, then fling it as far out of sight as possible.

Walk into "Ghetto", or any one of scores of slum settlements housing two million people in the Kenyan capital, and the scale of the task for one African city alone seems staggering.

At almost every turn, a sickly sweet stench of urine wafts from between the huts. Barefoot children play by trenches frothing with scum. The edges are strewn with telltale bags.

"First thing in the morning, the flying toilets are rampant," said Njoki, as a gaggle of other women in a courtyard nodded in agreement. "Sometimes you are walking down the path and you see human waste, people have just thrown it there."

Carbon Nanotubes, eh? (3, Funny)

jonbrewer (11894) | more than 11 years ago | (#5449159)

Let's hope this space elevator's fibers are a little more sturdy than the mast of Team NZ's yacht.

"AUCKLAND, New Zealand The meltdown of Team New Zealand, the America's Cup defender, continued on Friday when, on the third leg of Race 4 against the Swiss boat Alinghi, the Kiwis' mast exploded into a heap of carbon fiber shards."

'Because We Can' good enough reason? (5, Insightful)

GeckoX (259575) | more than 11 years ago | (#5449160)

I totally believe that Space Elevators are feasible in the near term. However, my concern is with whether we should. Is there a compelling enough reason that outweighs the risks involved to actually go and build one of these?

What risks you may ask?
Well, sure, shuttles are quite expensive to launch and are not flawless by any means. But what was lost recently? 7 lives, a bit of research and a relatively moderate chunk of change.

Ever thought about the effect of a disaster with one of these elevators? Use your imagination. Now remember that you have to use your imagination to even allow the concept of these being built so you can't just write off the possible effects of a catastrophe just because it's unlikely or far fetched...the whole idea is so if the idea becomes reality, well, likely so do many of the possible disasters that could come along with it.

Ever heard of the plan to build a dam across the mouth of James Bay, separating it from Hudson's bay? It was fully engineered and can be done...thank GOD nobody with more cash than sense has decided to back this idea.
Neato factor just doesn't cut it for me, I need real reasons that outweight the risks.

Alpha Centauri Strikes Again (1)

szquirrel (140575) | more than 11 years ago | (#5449164)

The Space Elevator

* Cost: 500
* Prerequisite: Super tensile solids
* Benefits: Doubles energy reserves production at this base and doubles mineral production rate at all your bases when producing orbital improvements; your units equipped with drop pods may now make orbital insertions anywhere on Planet; this project also waives any aerospace complex restrictions on orbital improvements.

We estimate that during the next mission century most of Planet's industries will be moved off-planet to Nessus Prime and other orbital facilities. Many of our industries will benefit greatly from the low gravity environments available in space, particularly those involving genetically engineered microbes.

CEO Nwabudike Morgan
"The Centauri Monopoly"

dear timothy (0)

Letter (634816) | more than 11 years ago | (#5449165)

dear timothy,

judging by the quality of comments so far for this story, i think that slashdot posters should be required to read the book in question before commenting on its book review. a little yes/no check box would do the trick:

Have you read the book being reviewed? yes/no

it would be like those web sites that check your age to make sure you are over 13 so that they can collect your information. this honor system is proven to work; there are no records of anyone under 13 selling their privacy on the internet since that law was implemented.


Strength? (1)

krugdm (322700) | more than 11 years ago | (#5449175)

Considering that a small paint fleck travelling at 20,000 kph can imbed itself [] through several layers of lexan, what's to to stop stray bolts from constantly clipping this thing in two?

Spread the Cost (was: Moore's Law) (5, Insightful)

GangstaLean (102189) | more than 11 years ago | (#5449179)

If the real and only cost barrier is carbon nanotubes, it seems like the best way to get this all to happen is to reduce the cost.

Okay, okay, you're saying, that's obvious. However we could look at another scenario to see how such things are possible:

Say we're sitting in 1983 or so, and we're saying, boy, it would be nice if all universities could have supercomputers and massive 10GB storage arrays to do computational exercises. Looking back 20 years, we know that's basically possible. The desktops of today were the supercomputers of yesterday.

So, let's figure out how to spread the cost. How can we incorporate carbon nanotubes into equipment that everyone needs/wants to use? Does it mean integrating it into automotive equipment? Consumer electronics? Clothing? What?

What would be the killer business/consumer application for carbon nanotubes?

If we assume that cost is a function of production size and research money, the best way to up both is to provide a market that's not pie-in-the-sky (forgive the pun). We can have cheap nanotubes in 10 years, but it seems that the best way to do that is to make nanotubes common everywhere, not by utilitizing the NASA budget (which is going to be under heavy scrutiny after the latest disaster).

Wear and tear? (1)

Junior J. Junior III (192702) | more than 11 years ago | (#5449183)

Even if something like this can be built and erected, how long would it last before it needed overhaul or replacement? Parts wear out, even carbon nanotubes.

Maybe there's a nanotech solution so that tiny repair robots can constantly be working on maintenance. How close are we to nanobots that can handle such a task?

space fuck (-1, Troll)

Anonymous Coward | more than 11 years ago | (#5449191)

it would be great to run this thing fast and then fuck your girlfriend while riding up! oh, wait, you assholes don't have girlfriends! sorry to intrude such an alien concept, guys. move along, nothing to see here.

What I want to know is: (3, Interesting)

TomatoMan (93630) | more than 11 years ago | (#5449192)

How can I be a part of this? How can I be involved in making it happen? I probably have no skills that would be relevant (unless they need a database backend designed and some Perl kung-fu for some reason), but I'll do anything. I'll sweep up at night. I'll make coffee and donut runs for the engineers. Anything. Just let me be involved somehow. I'll quit my job right now and move to Australia or wherever and live on bread and water and raw dreams.

/. Trek (-1, Troll)

Anonymous Coward | more than 11 years ago | (#5449194)

Beam me up Cowboy Neal

just because you can do something (0)

bigpat (158134) | more than 11 years ago | (#5449196)

Just because you can do something... doesn't mean you should. This would be a horrible waste of money.

This is precisely why the government should not be involved in pioneering space travel...the tendency to think big is not good in this case.

If the originators think this is such a great idea, then let them raise the money and do it themselves. I'll be the first in line to congratulate them, but keep my money away from this scheme.

Why (4, Interesting)

Hellraisr (305322) | more than 11 years ago | (#5449198)

Why does this remind me of Fred Flintstone using his feet to propel his car forward?

I guess any space technology improvement is a good one, but does it really need to be so brute-force-ish? Whatever happened to the NASA of old that created the shuttle?

They say that the next generation of space craft is still many years off, but I bet money could dramatically reduce the time frame (money always fixes problems like this - yay capitalism!)

I think it is good to at least gaze into the future of possibilities and while this certainly would make for cheap satellite launches, etc.. I am skeptical at how safe it would be to send humans up or back on it..

Say it comes to a grinding halt 1/2 way up. What on earth do you send to rescue the people off it this time?

Make my next stock purchase (1)

burgburgburg (574866) | more than 11 years ago | (#5449209)


A wholly owned subsidiary of United Technologies Corp (UTX).

Rather optimistic date projection (1)

MonkeyBoyo (630427) | more than 11 years ago | (#5449221)

The authors argue that carbon nanotube fibers are both strong and light enough that a 100,000 km elevator, constructed of a 2m wide carbon nanotube "ribbon," could be constructed in 10 years for a cost of US $6 billion

Given that nobody is currently manufacturing things out of carbon nanotube fibers, I find this 10 year projection the equivalent of vaporware. I think a very long period of R&D will be needed before a 2m ribbon can be constructed.

Spider Silk (1)

skroz (7870) | more than 11 years ago | (#5449222)

Interesting analysis of the materials. I wonder what the self support length of other materials might be. Like spider's silk, which is claimed to have tensile strength far greater than that of steel.

Traction (1)

cybermace5 (446439) | more than 11 years ago | (#5449231)

I always wondered what the "climbers" would hold on to. Carbon nanotubes are probably a bit slippery, like graphite. Are they going to punch chain holes in it? Also, how do the climbers adjust for the changing width and thickness along the ribbon?

Obviously the answer is not a space elevator, but a space escalator. Make it an endless belt that can be rotated. Provides a two-way transportation path, as well. The mass would have to be much larger though (continous profile along the entire length).

Earth - another ringed planet (2, Insightful)

pcraven (191172) | more than 11 years ago | (#5449246)

I worry if we make the cost so small, we'll have an artificial ring of space debris around our planet and we'll never be able to get out of here.

More links to NASA's space elevator project (2, Informative)

rpiquepa (644694) | more than 11 years ago | (#5449251)

Besides previous Slashdot stories about NASA's space elevator project, I also wrote several columns about this concept in the last months. If you're interested, take a look at "NASA Plans Elevators to Space [] ," "Pushing the space elevator closer to reality [] " or "Space tourism 'viable at $15,000 a seat'? [] ."

Ski lift not elevator (0)

SirLanse (625210) | more than 11 years ago | (#5449252)

Elevator that powers itself up the cable? NO WAY. It needs to be a loop that is powered from the ground, like a ski lift. The payload just gets into position and grabs the cable. It then lets go at the top. The only problem is the cable is twice as long and will wrap around the earth a couple times when it breaks and starts infernos all about the equator. If it werent for bad Karma I'd have not Karma at all.

Can we all say... (1)

torre (620087) | more than 11 years ago | (#5449261)

Going up?

sorry (0)

Anonymous Coward | more than 11 years ago | (#5449271)

Sorry for the unrelated comment, but I think this has to be posted. It concerns an example of the extremely ignorant attitudes towards war with Iraq: []

The sky is, uh, falling? (0)

Anonymous Coward | more than 11 years ago | (#5449275)

What chance is there that the cable acts as a wick and drains earths atmosphere out to space? How about bringing pollutants in from space? Are these derned scientists about to get us all killed again?

This project stinks (1)

CaffeineAddict2001 (518485) | more than 11 years ago | (#5449280)

This has far too many practical applications.

If you want to build a monument to humanity, I suggest we carve a peace symbol on the moon.... using nuclear weapons.

Nanotube bending radius (2, Interesting)

chiph (523845) | more than 11 years ago | (#5449285)

The book/article mentions that the ribbon will initially wound on a mechanism in LEO, and then unwound during deployment to a floating platform on the equator. Just wondering what the minimum bend radius is for nanotubes. If you wind it too tightly, you'd fracture a lot of the tubes, significantly reducing the ribbon's strength (you'd be relying on the cross-tube adhesive more than before).

Chip H.
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