Going Up?

jmiyaku writes "The National Post is reporting that NASA has given a Seattle company a $570,000 grant to continue its investigation into constructing a space elevator. Coupled with some production-grade technology from a Japanese car company (carbon nanotube composites), this elevator could be a reality within 15 years..." The Highlift website has some more information.

Comments

Environmental impact

[lonely]

One thing that worries me about orbital towers is the impact on the weather and the local environment. Something that big must affect local rain patters in some way...

Also what about the risk of it falling down? An orbital tower will wrap about the earth more than once if it falls. The description in Red Mars was particularly though provoking.

Re:Environmental impact

[breyguhn]

According to the article, it's a metre wide and paper-thin. Hardly a major contributing factor to global meltdown...

Re:Environmental impact

[barawn]

The Elevator in Red Mars fell down because it had an asteroid at the far end providing counterbalance. Separate the asteroid from the cable, and it's no longer a space elevator, but a really stupidly placed cable. Flop. Splat.

The elevator they're proposing is not counterbalanced - this requires it to be even longer than if it wasn't counterbalanced, but it doesn't require a conveniently placed asteroid. :)

Remember: you're asking what if it falls, right? It is falling. It just happens to be falling at exactly the same rate that the Earth is turning. It's in orbit. In order to make it fall, you'd need to break it.

Re:Environmental impact

[Christopher Thomas]

The elevator they're proposing is not counterbalanced - this requires it to be even longer than if it wasn't counterbalanced, but it doesn't require a conveniently placed asteroid. :)

Um, it's still counterbalanced - by the outer half of the cable. Cut the cable in the middle, and the bottom half goes "splat" just as effectively as if the counterweight was just a big rock.

Re:Environmental impact

[trance9]

Yeah but imagine if the cable breaks in the middle,
then 50,000 km of cable is going to hit the earth,
and the remainder is going to fly off into space.

Re:Environmental impact

[headwick]

Did you even read the website? This is a ribbon-like cable made of carbon nanotubes, not an enormous tower. The FAQ will answer your questions.

Re:Environmental impact

[rigelstar]

From the fax:

What if it falls?
The majority, the long end out in space, gains enough speed that it burns up in the atmosphere, with the lower portion falling into the sea. It will not fall on top of anyone.

For the portion that doesn't burn up in a fall- what effect will it have on the environment?
Honestly, it will make a little bit of a mess. But New York City tickertape parades have made bigger messes. Comparatively it will put much less dust, dirt, debris and chemicals into the environment than wildfires of the American west, any one of the large expendable rockets, or a month of natural meteors hitting Earth. The ribbon is light (7.5 kg/km) so, any pieces that fall to earth will slow down, in the air, to about the same terminal velocity as that of an open newspaper page falling. It will not have enough momentum to cause mechanical damage when it comes down. We have considered other health risks such as inhalation of very small fragments and believe this will not be a problem but we are conducting studies to make sure this isn't a problem. Since we are aware of the possible problems now we can design the elevator to avoid these problems.

How large a wave/disturbance would it generate?
The wave/disturbance would be nonexistent. As above, there just isn't enough mass, even in later, larger, ribbons, to generate such energy dispersion. There might be a small amount of light as a line in the sky as the ribbon burns up but after that it will be a few pieces of black film fluttering to Earth. Because of the size, distribution and winds, it is conceivable that only a few people would even see the event in any way and just as few would find actual pieces of the ribbon.

How much warning would there be from the time of a break and the time it would take for the lower portion to splash down?
Depending on exactly what happened it could be a few hours to weeks.

What would happen to the surviving portion?
The ribbon that fell to Earth could be recovered for study but because of the amount and distribution it would be difficult to find many pieces. The pieces that do land would eventually degrade but not for a very long time. Keep in mind that this is mostly a stable form of carbon; it doesn't do anything. The debris would resemble long hair and would probably be broken up in interactions with animals, plants, wind, fish and waves. In fiber form it would be much too large to inhale and would probably works it way through a digestive system unaffected. The only debris we have any concern about is if it were reduced to nanotube size. This we don't understand yet so we will study this to see if there is a problem and then probably also design the ribbon to remain in larger pieces if it re-enters.

Re:Environmental impact

[purpledinoz]

One thing that worries me in particular, is how Bruce Willis plans to escape from this elevator in the next Die Hard movie.

Re:Environmental impact

[Sj0]

I think there's some contradiction in there -- does it burn up in the atmosphere, or does it flutter to the ground like an opened newspaper?

Re:Environmental impact

[barawn]

Space elevators by definition are counterbalanced: what I was saying was that there wasn't a convenient break point, as in an asteroid-balanced one. It wouldn't be an issue - you'd need to break the cable, and that's a fundamental problem.

If you can break the cable, then yes, all hell breaks loose.

Re:Environmental impact

[Anonymous Coward]

read a little closer:

What if it falls?
The majority, the long end out in space, gains enough speed that it burns up in the atmosphere,

with the lower portion falling into the sea.

the upper part (above the atmosphere) will burn, the lower part will flutter.

Re:Environmental impact

[joshua404]

Also what about the risk of it falling down? An orbital tower will wrap about the earth more than once if it falls. The description in Red Mars was particularly though provoking.

The first thought that flashes through my head whenever I read about orbital towers and the like is "Babylon." I am all in favor of progress and technology, but the parallels you sometimes find between our modern ambitions and our Biblical ambitions are.. stirring.

Re:Environmental impact

[Anonymous Coward]

I wana pluck it like a big bango!

Re:Environmental impact

[dbrutus]

Actually, if you break the cable then it flutters down like a newspaper dropped from the... damn, start over. ...like a newspaper dropped from the Sears Tower. In the site's FAQ list they address the problem and the biggest unknown seems to be whether it's going to disintigrate into powder and cause some people to have a breathing problem. It's ~23.5 lbs per mile of cable so it isn't going to cause a tidal wave or anything. It's light, it's chemically very stable, it's unlikely to cause problems and has a projected space lifetime of about a thousand years.

Re:Environmental impact

[macdaddy357]

I don't think NASA's elevator stops on all floors.

Re:Environmental impact

[dbrutus]

The sin of the builders of the tower of Babel wasn't that they were trying to go high (our space launches have empirically demonstrated that isn't a problem) but that they were trying to reach Heaven. This elevator doesn't have a 'heavan' button so I doubt God will be offended.

Whatever source you're using for your religious enlightenment, broaden it.

Re:Environmental impact

[Lumpy]

HUH? An orbital tower will wrap about the earth more than once if it falls.
Oh sheesh....

All you need to do is get it out there far enough to make it economical.. the earth is approx 24,450 miles around.. if your counterweight has to be 35,785 miles from the earth's surface it will wrap around a little bit more than once... but I highly doubt it. it will more than likely snap and then disentegrate as the gravitional forces can now act differently on it.

your anchor in space will not magically start plummeting to earth when it's string get's broken.

Re:Environmental impact

[dbrutus]

In that case, I want two of them so they can be deuling banjos.

Re:Environmental impact

[Anonymous Coward]

Somewhat of a concern is what impact the environment will have on this elevator thingy.

Quote: "The climber is powered using a laser that beams at photo cells on the climber's underside."

Quote: "The proposed anchor zone is in the Pacific Ocean near the equator, where high winds and fierce storms are not common."

Things could get fun when one of these uncommon fierce storms hits.

"Ladies and gentlemen, this is your controller speaking. We are experiencing slight turbulence on account of the uncommonly fierce storm that just moved into position over the launch pad. While the cable is strong enough to withstand the winds, laser power is down to 12% and we will commence rapid descent to sea level shortly. It would be appropriate for you to scream now."

Weather is a tricky thing that does not bend to the wills of men and surprises will happen, especially if longer trips are to take a week - our ability to accurately forecast weather over that length of time is very sketchy at times. Global climate change, which is accelerating and will continue to do so given our current levels of activity, could (will?) also have unpredictable effects. It is not implausible that what is now a calm area of the Pacific could become a breeding zone for huge hurricanes over the lifetime of this project.

Re:Environmental impact

[mike77]

There's another risk other than weather and fallin. Well, maybe related to falling. It was recently discovered in a lab that carbon nano-tubes explode when photographed. turns out some guys who had been working on them, invited a reporter to the lab, and he snapped a picture and they exploded. CNT's apparently have no good way to dissipate heat, and the heat that built up from the flash was enough to cause combustion. So, whatever ya do, don't photograph the thing! ;)

Re:Environmental impact

[spike hay]

Also what about the risk of it falling down? An orbital tower will wrap about the earth more than once if it falls. The description in Red Mars was particularly though provoking.

Actually, it's not a tower. It's a tether. The best way to build a space elevator is to have a 15 mile high tower. Above that, you have a carbon nanotube robe that extends to GEO orbit. At GEO, there is some kind of counterweight like an asteroid. Or just a tether extending out another 24,000 miles, which can be used for interplanetary travel.

Interestingly, the thickness of the rope is greatest at it's end near GEO. The thickness on earth would be very thin.

The best material would be nanotubes in a fiberglass matrix.

BTW, if it came crashing to earth, it wouldn't cause much destruction. It would not wrap around the earth at all. It would fall straight down just like anything else. After all, it's speed is synchronized with earth's rotation. Most of the wreckage would land within a few miles of the base. And since the base would probably be in a remote equitorial island like one in the Maldives, it would not kill very many people.

Re:Environmental impact

[Anonymous Coward]

FOR EVERYONE'S CONVIENIENCE

The FAQ:

For the portion that doesn't burn up in a fall- what effect will it have on the environment?
Honestly, it will make a little bit of a mess. But New York City tickertape parades have made bigger messes. Comparatively it will put much less dust, dirt, debris and chemicals into the environment than wildfires of the American west, any one of the large expendable rockets, or a month of natural meteors hitting Earth. The ribbon is light (7.5 kg/km) so, any pieces that fall to earth will slow down, in the air, to about the same terminal velocity as that of an open newspaper page falling. It will not have enough momentum to cause mechanical damage when it comes down. We have considered other health risks such as inhalation of very small fragments and believe this will not be a problem but we are conducting studies to make sure this isn't a problem. Since we are aware of the possible problems now we can design the elevator to avoid these problems.

Re:Environmental impact

[maxwell demon]

What about the opposite scenario: Assuming it breaks near earth, it should be drawn into space by the centrifugal force. But since it necessarily crosses the geostationary orbit, which is used very much, isn't there a danger that it could do great harm to the sattelites there?

Also, given all the space scrap, how well can the elevator be protected against it?

Re:Environmental impact

[Anonymous Coward]

I'm also wondering about the effect (Uhm, I forget what it's called, but you know when you spin on a chair and hold your hand out and the chair slows down), Won't this have some affect?

Re:Environmental impact

[Flave]

Come on, you great big putz!

How much of an IQ does it take to figure out that there are plenty of people out there who have not read Red Mars and that maybe a spolier warning might have been warranted before posting the above?

I've just started reading the god-damned book and you've already ruined what must surely be a major plot point.

Crap.

Re:Environmental impact

[HawkinsD]

I think they said that they were going to coat it with something shiny.

Re:Environmental impact

[Izanagi]

But, look at the positive side! It would only take out Australia.

Re:Environmental impact

[coryboehne]

I'm sure they will think through these thing very carefully and make it as safe as possible to all concerned, however there are unknown factors... In the case of a world war this would be a very likely tatical target, as a matter of a fact terrorists right now would likely consider it a viable target. However there is a good chance that any attack on the cable would be done in the lower atmosphere, probably no more than 5 miles or so up, this leaves a minimal amount of cable to fall (since it is paper thin, and weighs very little this should'nt be a problem really) The bigger concern that I have is what effect COULD this have on Earth's orbit over the long run? The fact is we really don't know, there is tension on the cable so obviously the earth which is naturally balanced will be possibly thrown out of balance (even if it is ever-so-slight) The effects of this concern me far more than the possibility of the cable striking earth and causing damage. Another question to be answered is, how do they plan to keep it out of the way of air traffic, the moon, etc. A paper thin cable would be very hard to spot from the side, however being a meter wide it should be easy to spot from an angle or straight on. There are so many questions to be answered I would be very suprised if they had it done in fifteen years, but I hope they have a great success. Now that I'm done with concerns I'd like to move on to what good this could do, imagine being able to launch your own personal satellite! (yes I know there is WAY too much red tape for this to be a reality, but I can dream ok?) virtually any company could launch purpose built satellites for whatever purpose, how about a vacation to the moon or mars? This would actually make that somewhat feasable! I'm sure that these boys will be jumping hurdle after hurdle to get where they need to be, but I don't doubt that they will get there, it's just a question of when and at what cost.

Re:Environmental impact

[UranusHertz]

Read the info guys. Carbon nanotube ribbon weighs less than 8kg per kilometer. Not much environmental impact from that.

There are several whitepapers on the website that have a lot of information that will clear up a lot of the outdated information that people are getting from Sci-Fi novels.

Guess who can't wait for this!!!

[toupsie]

If you build it, they will come...

Re:Guess who can't wait for this!!!

[Anonymous Coward]

[Cue Love in an Elevator]

Re:Guess who can't wait for this!!!

[unicron]

I want to ride the space rails like a hobo..

"Remember, we're going the speed of light, so when you jump, try to roll."

Re:Guess who can't wait for this!!!

[AngryPuppy]

Yeah, and you can bet some damn kid will push all the buttons on the way up, too.

Easy target?

[grumwork]

Doesn't something like a Space Elevator become an incredibly large and tempting target for anyone looking to kill/injure/destroy American/Western World society? There cannot possibly be away to "guard" the entire length of the elevator on Earth, and if it were to break and come crashing down...

Re:Easy target?

[brejc8]

The thing is that its geostationary. For it to crash down it would need to first of all be thrown out of orbit by something really really big.
If you cut its connection with earth it will just hover there.

Re:Easy target?

[digitalsushi]

i think it would only just "stay there" if you snipped it twice, at the same moment, at equidistant spots from the center.

Re:Easy target?

[digitalsushi]

heh, you didnt even say that :-P how embarrasing for me

Re:Easy target?

[RobinH]

There cannot possibly be away to "guard" the entire length of the elevator on Earth, and if it were to break and come crashing down...

I would think that it could be controlled militarily. The obvious way would be for any nations that use it to either provide some kind of military forces (several countries have aircraft carriers, for instance, many others have submarines), or they could pay a 'security fee' to help support the operations of the other nations. I definitely think it's feasible.

You are right, though, the catastrophe if it snapped would be enormous. Perhaps you could make the bottom detachable in an emergency, so if you saw an attempt to break it in the middle, you could break the connection at the base and let it float off into space.

Just my $0.02

Re:Easy target?

[s20451]

If you were really smart, you would design it to be much longer than 35,000 km, where the orbital velocity is much less than geostationary, and apply a counterweight to shift the center of mass. That way, cutting the elevator would cause the entire assembly to be hurled into a higher orbit.

Re:Easy target?

[csimicah]

Based on what the article said, the "crash" would be somewhat like a sheet of newspaper falling to the ground. Not too worrisome unless a large piece landed on your windshield while you were driving, perhaps blinding you.

Re:Easy target?

[Anonymous Coward]

I kind of see the thinking of putting it out in the middle of the sea, but why not section off 10 square miles of some place in the middle of America. It should be very protected.

But on the other hand, I don't see many terrorists going after the Kennedy space center.

Re:Easy target?

[Wirr]

You are right, though, the catastrophe if it snapped would be enormous.

Why don't you all just read the FAQ ? Let me quote:

For the portion that doesn't burn up in a fall- what effect will it have on the environment?
Honestly, it will make a little bit of a mess. But New York City tickertape parades have made bigger messes. Comparatively it will put much less dust, dirt, debris and chemicals into the environment than wildfires of the American west, any one of the large expendable rockets, or a month of natural meteors hitting Earth. The ribbon is light (7.5 kg/km) so, any pieces that fall to earth will slow down, in the air, to about the same terminal velocity as that of an open newspaper page falling. It will not have enough momentum to cause mechanical damage when it comes down. We have considered other health risks such as inhalation of very small fragments and believe this will not be a problem but we are conducting studies to make sure this isn't a problem. Since we are aware of the possible problems now we can design the elevator to avoid these problems.

Re:Easy target?

[imperator_mundi]

The proposed anchor zone is in the Pacific Ocean near the equator,

somewhere far from America or Europa, but it has also this 100000km ribbon so it would wrap twice around the earth before hitting the ground.

More exactly: ribbon 100000km, earth circonference 42000km so after two orbits around the world there would be some 16000km left ... so the danger area is a circonference with 16000km radius and center at the anchorage point: if you're farther than that no problem if you're closer you should be at worst be hitted by the ribbon ... it shouldn't be so devastating ; )

Re:Easy target?

[satterth]

If you were really smart, you would design it to be much longer than 35,000 km, where the orbital velocity is much less than geostationary, and apply a counterweight to shift the center of mass. That way, cutting the elevator would cause the entire assembly to be hurled into a higher orbit.

Yeah, and it would pull the earth out of its natural orbit while its attached. Brilliant

Re:Easy target?

[DahGhostfacedFiddlah]

Perhaps you could make the bottom detachable in an emergency, so if you saw an attempt to break it in the middle, you could break the connection at the base and let it float off into space.

It's geosynchronous - it would just hover.

Re:Easy target?

[Oculus Habent]

And how do you propse to keep an elevator working if the top of it isn't above the bottom of it?

If you slow down the top, you'll create tremendous tension on the shaft, causing it to A) snap and cause horrible local destruction, not to mention the swath of chaos a broken dragging cable will cause; or B) slowly curve the elevator until it starts to fall to Earth.

If the system is geostationary (and I'd like to see one that isn't :) then a break in the cable will cause horrible local destruction as the bottom of the cable falls to earth. After some point (don't know enough about the physics of the situation to say where), it should stay where it is. If a break happens, there should be a destruct capability that would break away the cable below this point. If should break into sufficiently small pieces so it doesn't cause mass devastation.

The best place to put this cable would undoutedly be in the middle of the Pacific, on a huge floating installation, guarded by a fair portion of the Pacific Fleet. I imagine the UN would have control over it. That way any local damage caused by the failure of the cable would be greatly reduced (Oh no! We broke the ocean!) and the entire world could use it. Also, it would be hard to pretend to "accidentally" go near it without the military knowing.

--
Kaunakakai - We've got a POP there!

Re:Easy target?

[MADCOWbeserk]

Should be reasonably safe from attack. Given the expected remote location, a small Naval base could easily secure the airspace and seaspace for many miles around. A no-fly zone would be enforced to prevent accidental air collisions. Anyway there is very little flight traffic in those regions.

A bomb might be a greater threat, but cargo security will be tight. Any device will probably have to be shipped or flown a least a thousand miles just to get there so it is unlikely anything would make it. My guess is that passenger(consumer ) travel isn't going to happen for a long time. Probly not until a third or fourth elevator is built.

Still the idea was much cooler in Arthur C. Clark's 2061. He uses the diamond core that exploded from Jupiter when it became a star in 2010, as the building material.

Re:Easy target?

[dbrutus]

1. They're already planning on putting it in the middle of the Pacific in a zone of low/no Hurricanes and electrical storms

2. Why, oh why would you give this to the UN? It's a russian idea, popularized by an american author, and being funded by the US govt (NASA). through a grant to a US company. Most likely it will be built by 1 or more space companies (let's face it 10 billion isn't that hard to raise) and will place it under whatever jurisdiction they themselves find convenient which is likely to be the US.

The UN can't find it's backside with both hands. What's convenient about placing this under their jurisdiction? The Pacific is big. There's no reason that others couldn't pull together another $10B to build a competing one and considering the fact that would drop orbital costs to $100/Kg it's quite likely to be much less.

Re:Easy target?

[patiwat]

> Doesn't something like a Space Elevator become an incredibly large and tempting target for anyone looking to kill/injure/destroy American/Western World society?

Simple remedy to that: just build it in the Eastern World.

Re:Easy target?

[Anonymous Coward]

Actually, it would almost certainly fly off into space. There will be a minimum tension that runs throughout the ribbon because the ribbon doesn't have any strength in compression. So, I would expect that the ribbon is tugging at the base with a force just greater than the maximum load it is expected to carry (say 1 or 2 tons or more).

If it were just hovering, then when you pull on it, it would simply fall. My concern is what would happen if the load is carried a few hundred feet into the air and then the ribbon snaps at the middle (were the tension is the greatest). The load would then plumit to earth, destroying the base and potentially killing anyone manning the ribbon.

Re:Easy target?

[aaronsb]

According to their documents, the cable weighs 7.5 kilograms per kilometer. Somehow I don't think that would cause a lot of damage if someone were to drag it across the ground.

Re:Easy target?

[uchian]

The biggest problem would be for the poor sods stuck in space unable to get back down if the elevator snapped...

I assume that they will put some sort of emergency space ship at the top to pilot people back to safety?

Re:Easy target?

[antirename]

Ok, so large storms are uncommon. What about high winds in the upper atmosphere? Plus, harmonics from ANY wind are going to be a bitch to engineer around as the harmonics are going to change as the load moves (kind of like tuning a guitar string).

Re:Easy target?

[blablablastuff]

weather, for one, you can't really point to any place in america that doesn't have a pretty high risk of a heavy storm/wind at some point of every year. just watch the weather channel display how the jet stream moves sometime and you'd change your mind quickly. also the fact that to be geostationary it needs to be at the equator. The US Navy and Air force would be quite able to protect it. Well, them. anyone who wouldn't use the first one as a crane to put up the second one has to be at least mildly retarded. Why build 1 when you buy 2 for twice the price? And the second/third etc would actually be cheaper, since you launch them practically for free.

Going up?

[bokketies]

I sure hope it can get you down as well.

Re:Going up?

[Anonymous Coward]

I sure hope it can get you down as well.

as in "get down to boogie"?

Re:Going up?

[tx_mgm]

oooh! maybe we could use nasa's new crew return vehicle
how cool would that be?

Re:Going up?

[Indras]

Getting down is easy! Well, as long as you don't mind a potentially fatal case of rope-burn.

Optimistic

[Fenresulven]

this elevator could be a reality within 15 years...

Does anyone else think this is really really optimistic?

Re:Optimistic

[nick-less]

>>this elevator could be a reality within 15 years...

Does anyone else think this is really really optimistic?


I guess this is why he said "could" and not "will" ;-)

Re:Optimistic

[Anonymous Coward]

I think its absurdly optimistic. Unless he's just talking about the design for the elevator. That may take 15 years.

Re:Optimistic

[scott1853]

I remember reading an article back in 5th grade (1985) about how NASA was going to have affordable trips on the space shuttle by 1995.

Re:Optimistic

[Thud457]

Yeah, but that was NASA. There was no way a gubbemint bueracracy was going to fulfill a goal like that.

In the whole of recorded history, there is not a single instance of a bueracracy shrinking or becoming more efficient.

Now if Lockheed had been in charge, there was at least the possibility of that happening.

Re:Optimistic

[vicious_sloth]

How are you lifting it? shuttle? I thought they were just going to shoot it up there with some rockets. Its not that expensive

Re:Optimistic

[Anonymous Coward]

oops, should have read the faq. 7.5 kilos per kilometer. jesus. that's pretty damn light. when do they say they'll be able to make this?

on the other hand, they say it'll be 100,000,000m long, and let's say that'll push the lifting costs to the max $40,000 per kilo to get it higher in orbit (on average).

gives a cost to lift the cable of $30,000,000,000.

that's 3 x my original guess!

jasp

Re:Optimistic

[Anonymous Coward]

the highlift website quotes $10 - $40,000 per kilo depending on system and orbit. I was guessing cheapest, have revised my estimate to most expensive since it's so damn long.

Although you're probably right. Anything apart from the shuttle is probably $10k per kilo, shuttle $40k.

Re:Optimistic

[Oculus Habent]

Maybe it's a modular design. You know, build the first 200 stories worth and hang it from a big steel girder framework, and then build the next part and snap it together later...

--
Good thing Prometheus wasn't in Texas!

Re:Optimistic

[dbrutus]

Actually posted weight from the FAQ which you obviously haven't read is 7.5kg per kilometer so taking it as 320 kilometers (twice your assumptions that gives us a lift bill of 24 million which is a reasonable expense for lift and very easily held within a 10 billion dollar budget.

There are decimals in the wrong place alright...

Re:Optimistic

[reverseengineer]

Yeah, and that (1985) was also before Challenger exploded. Of course, 1995 would not have been a realistic date for affordable Space Shuttle travel anyway- costs would have been out of control to build that sort of infrastructure, unless NASA considered "affordability" to be in the Dennis Tito sense, and charged passengers 8 figures for a flight.

Re:Optimistic

[ApoxyButt]

Don't forget that initially they want to use rockets to launch a very thin ribbon into orbit. From one of their concept illustrations, it looks like the spacecraft would be equipped with a large spool. From the project summary on their website:

Initially, a small, carbon-nanotube-composite ribbon (10 to 20 cm wide and microns thick) capable of supporting 990 kg payloads would be deployed from geosynchronous orbit using four rockets and a magnetoplasmadynamic upper stage. Climbers (230) are sent up the initial ribbon (one every 3 to 4 days) adding small ribbons alongside the first to increase its strength. After 2.3 years a ribbon capable of supporting 20,000 kg climbers would be complete.

So, they get a tiny elevator in place, and use it to lift gradually larger loads of ribbon up into space. 2.3 years later, they've got the thing running at full capacity.

If you notice anything else in the project that doesn't quite make sense, rest assured that a wizard will take care of it.

Re:Optimistic

[dbrutus]

So what happens to the smaller ribbon? I don't think it gets combined with the other one, does it?

Re:Optimistic

[Dyolf Knip]

It'd probably be designed solely to lift up thicker pieces of ribbon and of little use otherwise. The first one would need to be very thin indeed to be able to fit a couple hundred kilometers of it onto a shuttle.

fifteen years?

[s20451]

According to this BBC article covering the same story, a fifty year timeline is more likely.

Re:fifteen years?

[endoboy]

Fifteen years is "funding speak" for:

"We don't have a clue on how long it will really take, but fifteen years sounds like a time frame that is close enough to get funding, without being so close that we actually have to deliver anything that works....."

Re:fifteen years?

[WolfWithoutAClause]

I've seen the project plan. It doesn't seem unreasonable.

The 50 year estimate was from NASA. The NASA guy is more or less paid to say that it will take much longer than it could, because if the project is successful it could lead to the massive scaling back of NASA's budget. By NASA spreading FUD on the project, he can put off the day that this happens.

Whilst it could reduce NASAs budget, my take on it is that NASAs budget might go UP if this was successful; but this risk sits uneasily with NASA, NASA is not noted for bold plans to reduce costs.

Re:fifteen years?

[Storm Damage]

The fifty year NASA plan, composed August, 2000, by D.V. Smitherman (which, by the way is available for download at the Highlift site) begins with several assumptions that this plan bypasses. Among them are that the cable will be tethered to the top of a very tall tower (Smitherman at one point suggests a tower 3000 km tall!), and the elevator cars will ride up the cable along maglev rails, which will provide power for ascending cars, and collect power from descending cars, along with solar power plants along the cable.

This plan seems to have abandoned the tower idea, simplified the transport mechanism by using mechanical means, and turned to a new power source. Of course, this plan doesn't provide the capacity that the fifty-year Smitherman plan does, but it does set up a very good first step and infrastructure to accelerate the construction of a second-generation elevator capable of meeting or exceeding the specs of the previous concept. As much is pretty much stated on the Summary page at Highlift.

Good idea for nuclear waste?

[pgpckt]

Well, Yucca Mountain leaves a whole lot to be desired. I suppose the best thing to do would be to shoot the radioactive waste into the sun. You could lanuch self-guiding ships full of the stuff straight into the sun...the sun sure wouldn't care. But how do you get the stuff in space safely?

Perhaps this space elevator? I think it should be safe(r). Use the elevator to take the radioactive waste top the space station, then build a craft to launch the waste into the sun. No more radioactive waste problem! And it would probably be cheaper than the current proposed solution, plus it would be really great for the space program and scientific development. Is this a good idea?

Re:Good idea for nuclear waste?

[zebadee]

Also a good idea for getting rid of those annoying polititions/celebs etc.

I think the sun was used for this in a Simpsons episode somewhere?!

Re:Good idea for nuclear waste?

[barawn]

It's not feasible to send waste into the sun - take a look through a few astronomy texts and you'll see why.

Basically the problem is that any object we lift from the Earth has energy, and angular momentum. If you want to hit the sun, and not just put it in a very eccentric orbit, you need to remove a lot of energy from the object, and the space elevator wouldn't help - it pulls you out of Earth's gravity well, not out of Earth's orbit. You'd require massive amounts of fuel to get it there.

Re:Good idea for nuclear waste?

[f00Dave]

The energy required to actually launch something 'into the Sun' from Earth is enormous. The Earth's orbital velocity is around 30 km/s, or 108000 km/h (~64800 mph). That's a LOT of delta-V to get rid of! I'll leave the details to the science geeks, but even with a gravitational slingshot (say off Venus), you're not gonna kill all that speed without entering atmosphere. The alternative would be to haul shit up to the graviational midpoint then let it slide along the shaft, accellerating and getting whipped off at 1G at the end of it, aiming it to smack into Jupiter or something, instead. ;-)

That whole 'spiraling into the sun' thing bugs me.

http://nssdc.gsfc.nasa.gov/planetary/factsheet/e ar thfact.html

Re:Good idea for nuclear waste?

[Fenris2001]

Not true - once you get past the midpoint of a long cable like this, you accelerate toward the end. All you do is let go at the right time.

Re:Good idea for nuclear waste?

[RickHunter]

Err... Doesn't a Hohmann-type transfer orbit (which, if I understand correctly, is the least expensive type of transfer orbit we've yet found) from Earth to Jupiter result in a very close (in relative terms) passage to the sun anyway? Wouldn't you just need a (relatively) small change in your orbit to plough into it instead of getting slung back out again?

Re:Good idea for nuclear waste?

[chocolatei]

When you say "That's a LOT of delta-V to get rid of!" - do you mean "That's a LOT of V to get rid of!"? Either way you don't need to get rid of it, you can hit the Sun at any V you like. With nuclear waste, that is. More to the point, just chuck it in space somewhere who cares where? It's hardly any more danger than cosmic rays.

Re:Good idea for nuclear waste?

[laertes]

Why don't you take some of your own advice?

Consider: we have to make the elevator extend past geosyncronous orbit (otherwise, what would be holding it up?) and connect it to a counterweight at the end. The smaller the counterweight, the farther it must extend. Now, if you are positioned at the counterweight, you are moving at supra-orbital velocity (your angular velocity is the same as it the angular velocity of something in geosynchronous orbit, but you are farther out. Also, tangential orbital velocity goes down as you go out.)

Therefore, if you let go of the space elevator at the counterweight, you will continue on tangentially to the orbit of the counterweight, but you will be in a very eccentric Earth orbit. The space elevator's utility would be much reduced it the tangential speed at the counterweight was not escape velocity for the Earth, so we could (reasonably) assume that it would be greater.

Now, if you release from the counterweight at just the right time, you will be heading in the opposite direction that the Earth is moving in, relative to the Sun. This means that you will be put in an eccentric orbit around the Sun, with your new perihelion much closer to the Sun than the Earth's.

If the elevator is long enough, then no further action need be taken, otherwise, a retrograde (I think that's the word) burn immediatly after release from the elevator can bring the orbit into one that intersects the Sun. There are more or less energy efficient ways to do the burn, but the point is that you already have a good kick from the elevator.

So, no you are not at all incorrect about the amount of energy requred--it takes a lot of energy to impact the Sun--but the elevator helps tremendously.

Re:Good idea for nuclear waste?

[barawn]

You're looking at it from the wrong point of view: from Earth's point of view. Look at it from the Sun's point of view. Even if you head backwards (against the Earth's rotation), you've still got a LOT of angular momentum to kill: orders of magnitude larger than any velocity you'll accumulate leaving the cable.

Figure it out: what's the circumference of the Earth's orbit? Divide it by one year in seconds, and poof, you've got your orbiting speed: 30 km/sec. They're talking about 120 - 160 km/h (hour!) or 0.04 km/sec. Then you've still got to eliminate 30 km/s. At that point you might as well have launched from Earth's surface: the additional benefit of the elevator is meaningless.

Re:Good idea for nuclear waste?

[Valacar]

If someday the elevator could provide significantly more reliable and safe passage into space than current rockets do, I would agree with you. I think the reason the idea of shooting this waste off of Earth has been dismissed in favor of storage in Yucca Mountain is that there is a much greater probability of the rocket carrying radioactive cargo crashing than there is of an earthquake or volcano breaking Yucca Mountain apart in the next ten thousand years. Also, the shuttle can carry 20 tons and this elevator could supposedly carry 5 tons. I don't know how many tons of radioactive waste we need to get rid of but I'm pretty sure it would require many risky space launches with the possibility of a crash contaminating a far greater area than an accident at Yucca Mountain would.

Re:Good idea for nuclear waste?

[f00Dave]

Yes, sorry, I meant a lot of V to get rid of (or delta V to be added) in order to create an orbit that will intersect with the Sun's atmosphere. But sure, who cares if there's radwaste kicking around in space, somewhere reasonably far away from where we expect to end up going? It would be a hell of a lot cheaper to just drop it on Venus or Mars, saving that we might want to live there someday (Mars, anyway, Venus is probably not worth it).

The only thing that makes smashing radwaste into a planet better than just setting it adrift is that, unless it's got solar escape velocity, it's just going to hang around our solar system forever. That's just delaying the problem. Further, if you dump stuff somewhere, and some future civilization decides it's actually USEFUL, then it's sort of hard to get it back from the Sun, eh? =)

The Moon is a much more logical dumping ground for radwaste, IMHO.

Re:Good idea for nuclear waste?

[aengblom]

It's not feasible to send waste into the sun - take a look through a few astronomy texts and you'll see why...You'd require massive amounts of fuel to get it there.

Oh, no. There are some waste products that should only be desposed of in this way--whatever the cost. For example: Richard Simmons

Re:Good idea for nuclear waste?

[barawn]

The counterweight's not being planned, for difficulty: they're doing it with a pure strand.

The difference in tangential orbital vel. is minimal here: you're talking about the difference between the Earth's position wrt Sun, and the top of the Elevator's position wrt Sun. They're identical, as far as anyone cares: it's six orders of magnitude difference.

But, anyway: figure it out. OK. Cable's 100,000 km long, right? That'll give you 7.3 km/sec let go at the highest point. You're right: that is a good fraction of the 30 km/sec needed to impact the Sun, but it's not all of it. And that remaining amount is just plain friggin' huge. You can figure out the amount that needs to be removed to hit the Sun (rather than direct impact) but it's still not going to be efficient.

There's another problem here, though: the elevator is located at the equator, and it is not rotating in the same plane as the Earth is wrt the Sun. It's rotating 23.5 degrees wrt the ecliptic. So you'll build up 7 km/sec, but of course, a large fraction of that is out of the ecliptic, which doesn't help you at all: in fact, 40%! So really, the elevator only helps you out with ~ 4 km/sec against the 30 km/sec you're traveling. Plus now you're moving out of the ecliptic, so that additional 3 km/sec actually adds to the amount you need to get rid of, if only slightly.

Bottom line: 26 km/sec vs. 30 km/sec: it still sucks.

Re:Good idea for nuclear waste?

[Pig Hogger]

It's not feasible to send waste into the sun - take a look through a few astronomy texts and you'll see why.
Basically the problem is that any object we lift from the Earth has energy, and angular momentum. If you want to hit the sun, and not just put it in a very eccentric orbit, you need to remove a lot of energy from the object, and the space elevator wouldn't help - it pulls you out of Earth's gravity well, not out of Earth's orbit. You'd require massive amounts of fuel to get it there.

You only need to slow it down enough for the orbit to decay. A very good way of doing so for practically free is to attach a solar sail to the garbage packet. The solar wind will then simply slow it down so that it's orbit decays sufficiently to eventually hit the Sun.

Re:Good idea for nuclear waste?

[opposume]

They sure did! God rest Tom Arnold, Rosie O'Donnel, and Polly Shore just to name a few of the hapless celebs who were seated on THAT ill-fated flight. LOL

Re:Good idea for nuclear waste?

[f00Dave]

The point is that we don't WANT to spend fuel on this problem and Hohmann orbits require a burn. Like I said, there's not enough velocity at 'release' to have the orbit intersect the Sun. Now, plowing the radwaste into the Moon is a much better idea, overall, and should be easily accomplished from The Ribbon (I haven't done the math to be sure, hence the 'should', but since the Moon already has the Earth's orbital velocity, there's obviously a LOT less delta-V required....).

Besides, as I said in another reply, we might WANT that radwaste in the future, sometime. =)

Re:Good idea for nuclear waste?

[zbuffered]

In that case, we need a carbon-nanotube earth to sun elevator.

Re:Good idea for nuclear waste?

[RickHunter]

Besides, as I said in another reply, we might WANT that radwaste in the future, sometime. =)

Point. And dropping it onto the moon lets us leave it, retrieve it, or move it around without worrying about damage to any sort of functioning ecosystem. The only potential problem I can see is asteroid impacts... And even then, that's not a problem if you bury it deeply enough.

Re:Good idea for nuclear waste?

[barawn]

Correction: you don't mean solar wind. You mean light pressure. Solar wind is made of charged particles, which wouldn't work that well for the solar sail issue. Light pressure is better. But anyway...

Light goes out radially: how would you slow it down using this? It's constantly pushing it outwards.

I've always been confused about this: how exactly would you move radially inward against something that's moving radially outward? This isn't like sailing where you have something else to push against. I can't see anyway to get a net velocity inward.

Re:Good idea for nuclear waste?

[Oculus Habent]

The subducting seafloor idea sounds much better to me. Drop in into a hole in the ocean floor, and it is pushed into the mantle. No loss of mass for the earth, no huge expenditure of energy, and the waste is taken care of.

Re:Good idea for nuclear waste?

[f00Dave]

Sounds good, save that if the 'waste gets hit by a rock from space, I doubt it'll do any more damage to the container than the initial impact did. Odds on a huge rock hitting a small container that's already going to be under the middle of a crater, somewhere are vanishingly small. And even if it did, it'll just smear the active ingredients around, or turn it into ejecta. Either way, it's *waste*, so we don't care what happens to it, right? =]

Re:Good idea for nuclear waste?

[barawn]

Woo. That'd be one HELL of an oscillation to avoid Venus and Mercury. Damn them for being in the ecliptic!

Re:Good idea for nuclear waste?

[Dark Lord Seth]

However, dumping it on the moon would be hampering further development of any lunar colonization. Suppose they find water in a crater on the moon, but someone dropped a few hundred tonnes of radioactive garbage on top of it... Not exactly the thing we want.

The moon though, would be an ideal launch site to get rid of this waste... Just build one large mass-driver, load the waste on it and shoot it wherever you don't care like the Sun, outer space or France...

Re:Good idea for nuclear waste?

[Capt. DrunkenBum]

Space 1999 anyone?

And only 3 years late.

Re:Good idea for nuclear waste?

[tx_mgm]

"the SUN?!?! But, thats the hottest place on Earth!"
-homer

Re:Good idea for nuclear waste?

[Anonymous Coward]

then launch it into deep space, there is no one out there for it to bother.

Re:Good idea for nuclear waste?

[Elgon]

Shooting nuclear waste into the sun (or even just into orbit) is a complete waste of time as this takes more energy to do than you ever get out of the material in the first place. OTOH, the nuclear indstry is so highly subsidided that it would be able to afford to do this if such a space elevator were to be build - can anyone say "Perverse Incentives?"

Elgon

Re:Good idea for nuclear waste?

[Anonymous Coward]

why don't we just ship it to LA California? The people there are already freaks, who would really notice :)

Re:Good idea for nuclear waste?

[Henry V .009]

There isn't a whole heck of a lot wrong with Yucca Mountain.

And if no-glow nuts are worried about semi-trucks now, imagine what they'll think about space ships hauling the waste right above their heads.

Re:Good idea for nuclear waste?

[Brandeissansoo]

Safe?!@ What about the superbeing that will come out of the sun after the missile get there? (If you didn't see superman IV...)

Re:Good idea for nuclear waste?

[Anonymous Coward]

You need to keep the mass of stuff on earth constant, you can't just throw litter down, that's naughty, you should put it in the bin bin. :-)

Re:Good idea for nuclear waste?

[asparagus]

Interstellar tacking?

Actually, since the mass/velocities that can be moved by solar "sails" aren't that much, I believe they generally drag along a chem/ion motor of some type for both small/precise manuvering and as an emergency feature.

Sort of like having a motor in a canoe, just in case you drop the paddles overboard/don't want to row like mad to make it to the shore.

-asparagus

Re:Good idea for nuclear waste?

[Milk and Cookies]

Yes, it is very likely that the waste put into Yucca Mountain will be safe for as long as the containers don't corrode. That is supposed to happen after about 10,000 years, IIRC. Does anyone else see a problem with this? If we're still around in 10,000 years, our decendants are going to hate us for filling a mountain full of nuclear waste. Sure, by then we may not be around anymore, we might be able to safely clean up the waste, it might end up as big of a disaster as the Y2K bug was, but still 10,000 years seems a little short for nuclear waste. Other, longer lasting methods, have been regected--one country is encasing thier nuclear waste in granite, making it safe for something like half a million years.

Re:Good idea for nuclear waste?

[dpilot]

I have this inherent belief that unchecked, we can pollute ANYTHING, and that includes the Sun. Even if it were feasible to send nuclear waste to the Sun, and there has been plenty of more-than-adequate refutation, I would worry about sending uncontrolled quantities of heavy metals.

It's only small amounts, compared to planetary or solar mass, but what if it acts as a catalyst, not being used up, but continuing to cause mayhem? (I read Asimov's "The Currents of Space" as a kid.) I wouldn't anticipate anything like a Nova, but what about increasing the number or severity of flares, and the effects on communications?

Re:Good idea for nuclear waste?

[asparagus]

Dah.

I just realized you meant inward. I belive the current research is to throw said object toward the Sun using gravity slingshots + some sort of rocket, then to use solar sails to slow things down and push you back out to your destination once you pass it up.

Solar sails are kinda more cool than useful, though. If we ever need to move tons of unmanned crap from earth to mars, they'll be useful, but for most missions an ion drive is better.

-asparagus

Re:Good idea for nuclear waste?

[Psion]

Damn them indeed. Break 'em down and use them to build the thing!

Re:Good idea for nuclear waste?

[dragons_flight]

Assumming a stiff space elevator that rotates at the same speed as the Earth (ie. once per 24 hours), then to kill the 30 km/s velocity of the Earth with respect to the sun, you'd have a space elevator that is 30km/s /(1/24hr) = 2.5e6 km. For comparison, the distance to the moon is only 3.8e5 km.

Since the length and mass distribution of a space elevator is highly constrained by the need to have it orbit once per 24 hours, I highly doubt that that anyone is contemplating building one more than a factor of 2 past the 3.5e4 km that defines geosynchronous orbit, and certainly not 7 times past the orbit of the moon.

Certainly getting it away from the earth is a big plus, but it isn't going to help much in getting it to go towards the sun.

Re:Good idea for nuclear waste?

[cybercuzco]

Were you aware that the sun is a Giant ball of radiation? Were you further aware that that electromagnetic RADAITON is bathing the earth every single day? Dangerous solar RADIATION is known to cause CANCER in human beings. Why would we want to add to that radiation by slinging nuclear waste into the sun? The sun is also an unstable environment, if that nuclear waste went critical it could explode with the force of thousands of hiroshimas, possible damaging the sun and causing more harmful RADIATION to be spread to earth.

In case you couldnt tell, i was being sarcastic ;-)

Re:Good idea for nuclear waste?

[RickHunter]

The moon's gravity's too low for long-term lunar colonization to feasible. And remember, most of the moon is provably barren rock. Not only that, but the stuff's going to be creating its own crater when it lands, so you're not exactly leaving the existing terrain in pristine condition here.

Re:Good idea for nuclear waste?

[diablovision]

Perhaps this space elevator? I think it should be safe(r).

The problem isn't the safety of the space shuttle, heavy lift rockets, or any of that. It's the prohibitive cost of launching so much sheer tonnage of material into space. The US alone has hundreds of thousands (possibly millions) of tons of radioactive waste from decommissioned weapons, reactor waste, industrial waste, and medical waste. Launching all of it into orbit (alone) would take thousands upon thousands of launches. At a few tens of millions a piece, it's not exactly cost effective to even bother.

The safety would be an issue, of course, if they were planning to actually do it, but the sheer cost rules it out before safety is even a consideration.

Re:Good idea for nuclear waste?

[Guppy06]

"You could lanuch self-guiding ships full of the stuff straight into the sun...the sun sure wouldn't care."

Especially since, odds are, you'd miss the sun entirely. Moving something to the center of a gravity well is much more difficult than those who know nothing about orbital mechanics believe. You're more likely to have that waste whizing right by the sun, getting yanked back around by the sun's gravity and smacking right back into the earth.

Re:Good idea for nuclear waste?

[f00Dave]

I'm willing to bet that a 'dump site' could be chosen quite far away from the site of any currently-proposed or reasonably-conceivable colony. Further, the Moon is a damned huge chunk of rock. Assume that a dump site covers, oh, a million or so square miles (yeah, a squished square, on the equator, about a thousand miles on an edge. The actual target site is a square mile in the middle of it. That still leaves about 36 million square miles of surface area. For comparison purposes, the entire surface area of *North America* is about 9.3 million square miles.

Basically, if there's water under some crater in the dump site, there's going to be water somewhere ELSE, too. Keep in mind: the moon has no ecosystem to destabilize, no indigenous life, no open bodies of water to pollute and won't be an 'eyesore', even if we DID smash thousands of tons of radwaste into a square mile or ten ... now, if you started to write "Chairface" on it with a Big Frickin' Laser, that's another story. =)

(Quick) References:
http://www.spacegrant.hawaii.edu/clas s_acts/MoonFa cts.html
http://www.globalgeografia.com/north_ame rica/north _america.htm
http://caboodle.tripod.com/tick/chai r.htm

Re:Good idea for nuclear waste?

[Anonymous Coward]

You are right, that is a huge delta-V. However, if a solar sail were used, then the materials could be eventually transfered to the sun. In fact, this is really the ONLY way that this could be accomplished cost-effectively. It could accomplish this with virtually zero rocket propellant and would be rather cheap to construct (we're not in a hurry, after all :).

Re:Good idea for nuclear waste?

[Reality Master 101]

Dude, the sun (at 2 x 10^30th kilograms) is about 300,000 times the mass of the EARTH, which is 6.0 x 10^24 kilograms. We're talking about disposing about 7 x 10^7 kilograms of nuclear waste. That's only a ratio of 2.86 x 10^22 kilograms.

The sun ain't gonna notice it.

Re:Good idea for nuclear waste?

[ivrcti]

Quick, call the Vogons!

Re:Good idea for nuclear waste?

[dillon_rinker]

Adding delta V? Increasing the rate of acceleration? Don't you think you just meant "a lot of delta V"?

Pick, pick, pick =)

\

Re:Good idea for nuclear waste?

[Anonymous Coward]

I have this inherent belief that unchecked, we can pollute ANYTHING, and that includes the Sun

Judging from the quality of knowledge in this comment, we can also polute Slashdot message boards...

Re:Good idea for nuclear waste?

[Reality Master 101]

Oops, I should have said 7x10^7 KGs at Yucca Mountain.

Re:Good idea for nuclear waste?

[shess]

It's easy enough - you use the solar sail to cancel your orbital velocity by tacking, then you fall into the sun.

The best part is that you don't even need that effective of a sail, once you're out of earth orbit. You need just enough to cancel your sun-orbital velocity a little. You'll fall inward to a new orbit - which is closer to the sun, and thus your sail becomes more efficient. While it might be hard to sail into the sun in a week or month, it should be pretty easy to accomplish in a year or decade.

Re:Good idea for nuclear waste?

[Anonymous Coward]

I have this inherent belief that unchecked, we can pollute ANYTHING, and that includes the Sun

I have this inherent belief that you're a moron.

Re:Good idea for nuclear waste?

[Necron69]

You guys are missing the obvious fact that space is swimming with radiation. Harmful radiation is a norm in the universe, just not on Earth. Just dump the radioactive waste on the moon or someplace where there isn't a biosphere to harm. Why bother trying to drop it into the sun?

- Necron69

Re:Good idea for nuclear waste?

[elmegil]

Who's to say the waste itself can't be used to generate some kind of energy to provide some kind of thrust?

Re:Good idea for nuclear waste?

[f00Dave]

The whole point is to get rid of the radwaste ... it's *garbage*, so we'll want to spend as little time and money on it as we can. Ergo, strap a disposable 'crawler' on the container (cheap in mass quantities), send it up the ribbon and then just let the whole mess sail off unguided and unpowered to the Moon, where it digs itself a shiny new crater. This solution is cheap, recoverable if we need it later, and no longer a problem for Earth, right? Right.

Think practical, not fanciful, when dealing with politicians, money and engineers. =]

Re:Good idea for nuclear waste?

[dpilot]

At first blush, I would definitely agree with you. The mass difference is just *too* great.

But mankind has a *terrible* track record at thinking it can get away with stuff. So far it seems that every time we try to cut a corner it comes back to bite us, eventually.

Other than the energy cost, tossing waste into the Sun just seems too simple and too final to really be simple and final. The other good argument other than energy cost is that someday this stuff might be a valuable resource. We should just be finding a good method of safe, indefinite storage with eventual accessability. The Moon is a good idea, as long as Martin Landau and Barbara Bain don't blow it up and kick the Moon out of orbit. (second obligatory Space 1999 reference on this subthread)

Re:Good idea for nuclear waste?

[embeesh]

He added it, just in the other direction!

Re:Good idea for nuclear waste?

[Jeppe Salvesen]

Couldn't you use a slower propulsion system? After all, you would no longer need to fight the drag of the atmosphere, and not as much gravity, either. Since you don't have to go vertically, you can just gather speed orbiting, and then fire some secondary system that kicks your course into space. Am I smoking pot?

Re:Good idea for nuclear waste?

[ajs]

Correction: it would require a huge amount of energy. Given that you're trying to fly into the largest producer of energy in the local area, it's just a matter of producing an engine that a) can use that energy efficiently enough to get into the right trajectory and b) making it cheap enough that it doesn't cost billions per shipment.

The other nice thing about the elevator is that it removes a lot of the danger of throwing waste materials into space. The big concern when you're throwing tons of plutoniom, for example, into space is that the launch vehicle might fail and fall to earth. With this scheme, you can afford to send many more, much smaller payloads up. If you drop 2 pounds of plutonium into the ocean, it's a bad thing, but it's a managable risk. It's also much less likely to happen, as the largest chunk of risk is when you put the elevator up, not when you use it!

Re:Good idea for nuclear waste?

[barawn]

Velocity is velocity is energy. If you're going 26 km/s, then you're going 26 km/s, and you're going to need to burn a hell of a lot to get rid of all of the energy. If you use a slower propulsion system, then you need to use it a much longer time, and you need much more propellant.

(OK, someone suggested solar sails, and it must be possible, but I still don't understand it. Still, there you're talking years/decades, and a LOT of extra mass tacked on)

It just isn't feasible, and it sure as hell isn't free.

Re:Good idea for nuclear waste?

[ApoxyButt]

Perhaps you could use a mass driver system to chuck portions of the waste back at Earth to provide the extra push necessary to get on course to the sun. You could even target certain areas of Earth, like France. Really, I don't see a down side.

Re:Good idea for nuclear waste?

[Kashif Shaikh]

That whole 'spiraling into the sun' thing bugs me.

That's when you know people used to watch Superman too much.

Re:Good idea for nuclear waste?

[surfcow]

>...shoot the radioactive waste into the sun...

The romans dumped lots of crude oil into the sea. They were certain it had no practical use for anything. Today we use it for many things from plastics to medicines to fuel.

And we also have a irritating substance to deal with. I hope we have the imagination to see it's potential future uses.

=brian

Re:Good idea for nuclear waste?

[Anonymous Coward]

Don't think of it as a sail--instead think of it as a parachute.

Re:Good idea for nuclear waste?

[csimicah]

Tacking may be difficult because photons are not viscous like air. You can expose more of less of the sail to the "wind" but the direction of the force is always going to be directly away from the sun.

Re:Good idea for nuclear waste?

[spike hay]

"You could lanuch self-guiding ships full of the stuff straight into the sun...the sun sure wouldn't care."

This space tether looks pretty failsafe. According to the companie's FAQ, it will be able to support twice the weight of the tether and it's cargo. You could simply just fling the waste off the end into interplanetary space. (To a higher orbit, obviosly)

Of course, it still would be expensive. This will launch shit at 1/100 of the cost of the shuttle. That is still $100 bucks a pound. Anyway, we can store nuclear waste safely here on earth. And we might want that spent fuel later on, anyway.

Re:Good idea for nuclear waste?

[barawn]

Actually, as I pointed out somewhere else, your calculation is off by about 40%, since you're shooting the object 23.5 degrees out of the ecliptic. Plus that also is a problem since even if you cancel off all of the 30 km/s, you'll have the residual 12 km/s out of the plane of the ecliptic, which will just produce a very elliptic orbit. Propellant, propellant, propellant. You'd probably want to cancel off all but 6 km/s ecliptic + 4 km/s out of ecliptic (~ 7 km/s tangential). 7 km/s is still a lot to get rid of. It isn't free - no way.

Re:Good idea for nuclear waste?

[barawn]

Nah - actually I thought about this for a while, and I realized where my mistake was. It's not tacking, but it will work.

You can change the direction of the force by changing the direction that the light reflects. That is, tilting the mirror. If you do that, then the net force is at an angle, and you can cancel orbital velocity. It will increase your radial velocity a little, so it'll ellipticize your orbit. You then fold the sail, and let the decreased tangential velocity bring you closer to the sun, and then do it again at the opposite end of the orbit as when you did it before. This circularizes your orbit slightly, and pulls the other end closer - step and repeat. It's slow, and more importantly, it needs to be monitored and controlled, which means it's expensive. But it would work.

It's not tacking, though - not even similar.

Re:Good idea for nuclear waste?

[delcielo]

Presumably the nuclear waste isn't completely spent. Could you use the remaining energy in the waste for propulsion, somehow?

Re:Good idea for nuclear waste?

[Reality Master 101]

But mankind has a *terrible* track record at thinking it can get away with stuff. So far it seems that every time we try to cut a corner it comes back to bite us, eventually.

Actually, mankind has a GREAT track record of "getting away with stuff". There are very few instances where we've done some sort of damage that was irreversable. Obviously hunting certain species to extinction would be an example of something irreversable, but there's not that many cases of that.

The biggest fallacy of the environmental movement is that the earth's environment is fragile. Nothing could be further from the truth. If the conditions on earth were fragile, it would have been impossible for life to have survived as long as it has because the Earth has gone through natural cataclysms that make man's effects look like child's play.

That's one of the reasons that I think global warming caused by man-made processes will turn out to be a huge scientific hoax. The equilibrium processes of the Earth are much more powerful than they are given credit for. This is not to say that global warming isn't happening, only saying that mankind has little to do with it.

Re:Good idea for nuclear waste?

[Anonymous Coward]

2 pounds of plutonium contains enough plutonium atoms to give every single human being on this planet cancer.

Re:Good idea for nuclear waste?

[Tablizer]

(* Who's to say the waste itself can't be used to generate some kind of energy to provide some kind of thrust? *)

If the radioactivity is allowed to "leak" out in one direction, wouldn't that provide an ion-like engine thrust?

True, it would take a while, but as long as it continues to get further and further from Earth over time, who cares.

I figure it would orbit Earth, but at an ever-increasing distance. Eventually it would break free of the Earth's pull and orbit the solar system on its own. Then it slowly decays its own solar orbit until it lands on the Sun.

Let's just hope the Sunnanites don't send us a bill.

Re:Good idea for nuclear waste?

[dunedan]

would you prefer *elipsing* into the sun?

Re:Good idea for nuclear waste?

[barawn]

It's not energy - it's angular momentum.

You need some way of generating thrust to counteract that momentum so you can fall easily. If you want something that doesn't require propellant, you're talking about a solar sail, and that requires a lot of course corrections to sail into the Sun. It also would probably take quite a bit of time, and require a fair amount of extra material. That is, money.

Re:Good idea for nuclear waste?

[Vuarnet]

The subducting seafloor idea sounds much better to me. Drop in into a hole in the ocean floor, and it is pushed into the mantle. No loss of mass for the earth, no huge expenditure of energy, and the waste is taken care of.

Yes! Finally, a voice of reason among all these futuristic ideas about flinging nuclear waste out into space.

You, sir, deserve a karma raise. Keep it up!

Re:Good idea for nuclear waste?

[malen]

It's definitely possible to lower one's orbit with a solar sail: angle the sail opposite its orbital velocity, and there will be a thrust component outward radially, and another component against the orbital velocity. The retrograde component will overwhelm the radial component, and the orbital velocity will decrease, resulting in a lower orbit.

Re:Good idea for nuclear waste?

[terrymr]

But if we could use it for propulsion it wouldn't be waste any more would it ?

Re:Good idea for nuclear waste?

[An Onerous Coward]

You know, as dangerous as nuclear fuel might be, it's not exactly time-critical. Just strap a solar sail onto the thing and use that to dissipate the energy. Maybe it'll take a few hundred orbits, but there's no rush. Alternately, you could use some solar panels to drive some cheap ion propulsion. Again, perfect if you're in no hurry.

Re:Good idea for nuclear waste?

[dragons_flight]

You're wrong.

The end of the elevator will follow a circle which is inclined with respect to the ecliptic. Let us say that the z direction is perpendicular to the ecliptic plane, then the end of the space elevator has z = R*cos(w*t)*sin(phi), where R is the radius of it's orbit, w is an angular frequency, t is time and phi is the angle of inclination relative to the ecliptic plane. Therefore v_z, the velocity in the z direction, = -R*w*sin(w*t)sin(phi). Clearly there are times when v_z is 0, and the question then becomes are there any times when v_z = 0 and the rest of v is pointed opposite to the motion of the Earth.

I claim that both these conditions are satisfied at 12 noon on the summer and winter solstices. I could prove it, but that would take a lot more space, and I'm hoping you'll understand without my taking the effort.

Besides, it's all moot, since we aren't going to be throwing waste at the sun from some rope ten times the distance from here to the moon.

Re:Good idea for nuclear waste?

[dpilot]

In the long run, *everything* we've ever done is reversible. In the short term, (next century) we're going to be making it darned uncomfortable for ourselves and co-inhabitants. In the medium run, we're destroying a lot of genetic diversity, which is nature's toolbox. The bigger problem with our "getting away with stuff" isn't the unsightly or smelly pollution, it's what it does to natural habitats. Kind of like the dead lakes in the Adirondaks. Or how about those little furry proto-mammals at the end of the Cretaceous.

As for fragile, I agree that the Earth's environment can take anything we can dish out. However, I disagree that we can keep dishing things out and remain comfortable. The environment flexes, perhaps not more than our species does, but clearly more than our societies.

I agree that Earth's natural forces can overwhelm anything we do, but I disagree in that I believe we can nudge the natural order around. Witness the recent research into contrails around Sept 11 causing a noticable effect on the weather, though ramifications are not yet understood. (Maybe nothing at all, maybe not.)

Re:Good idea for nuclear waste?

[dpilot]

Think a little harder, flame a little less. Most of the ridicule toward this basically states, "The Sun is soooooooo big, we're soooooooo small, we can't possibly have any effect." I simply argue against that process, because I believe we've disproven it here on Earth. As mentioned elsewhere, check out the recent studies of contrail influence on weather around Sept 11.

As for the Sun, it's got more heavy nuclei down in the core than we can ever think of throwing at it. But there are two things to think about. First, it's down in the core, not up in the photosphere or chromosphere. Second, anything that hits the Sun does so in a small space, not spread throughout the total volume. Local concentrations would be higher. Probably no problem, but could it catalyze a flare? Maybe.

I don't predict doom or flares. I dislike a mindset that says, "We don't have to ever be careful about disposing of junk this way."

Re:Good idea for nuclear waste?

[dragons_flight]

Actually it's very easy to get something to crash into the sun. Just place it up there and leave it alone.

Photons carry momentum, relativistically there is non-zero angle (~v/c) between the apparent direction of motion of the photon and the line between the sun and the object. Absorbing photons consequently imparts momentum which has a component opposite to the direction of motion of the object about the sun, hence removes angular momentum.

Provided the surface area of the object is not really large compared to it's mass, ie, it's not solar sail, this effect dominates over light pressure and causes the orbit to decay. For small (~ 10 m) meteors at 1 AU in circular orbit the characteristic time before it collapses into the sun is about a million years.

The same principle would apply to canisters of waste placed in solar orbit, which is fine provided you don't mind waiting a million years for it to get to the sun.

If you are interested the characteristic time goes proportional to density*object size*(distance to sun)^2, and is roughly 10^16 years for something the size of the Earth (ie. it's not horribly relevant).

Re:Good idea for nuclear waste?

[barawn]

Do you remember the name for this effect? I always forget it - there's it and the competing effect for objects that are very small (light pressure). It's in Carroll & Ostlie, but my copy's in my office, and I'm not.

In any case, you're right, but the timescale is so huge that it again proves the point. It's not feasible - it might as well be a waste dump for as long as anyone is around to care.

Re:Good idea for nuclear waste?

[dragons_flight]

No, I don't remember the name for the effect. Actually I think that I am off by a factor of 10^3 (grams and kilograms are the same thing, right?). 1 Million years, 1 Billion years, doesn't make a lot of difference to the point.

Re:Good idea for nuclear waste?

[barawn]

I'm not wrong: I'm just not always right. :) Most of the year a significant component will be thrown out of the ecliptic, and no matter what, you're always going to be in an orbit that's out of the ecliptic, it's just a matter of whether or not you're already aligned with that plane.

Although, good point. If the elevator was absolutely gigantically huge, it would work. Hadn't quite thought of that... wonder why. :)

And as for moot points, to resummarize:

1: You can lose a lot of the 30 km/s simply by using the velocity of the far cable.
The maximum you can lose is roughly 8 km/s. The minimum you can lose is 4 km/s. Most of the time you'll lose somewhere between the two. You get two shots at the minimum.

2: You can use planets as gravity slingshots. Well, yes, but it'll take a hell of a lot of 'em to do it. Probably around 5 or 6 - most likely more. It would also most likely require course corrections, which defeats the purpose (propellant mass).

3: You could wait a long time and have them fall in via the effect I can't remember. While this is true, it also defeats the purpose. Having something to track and pay attention to in space costs more money than it's worth.

4: You could use a solar sail to push them in. Same problem as above. It takes forever to do it, which defeats the whole purpose.

Jeez. The whole initial point that people started arguing with was that a space elevator doesn't help you with getting rid of trash. All of the problems listed above are far more costly than the initial surface-to-Earth transit. The elevator doesn't help you with the basic problem that you have 30 km/s of rotational velocity to deal with, and you need to get rid of it.

Re:Good idea for nuclear waste?

[juhaz]

It's not like it's going to grow a legs and walk out of the damn mountain even if something happens to the containers. That's why they though long before choosing a place, and didn't just throw those containers into the next junkyard.

The freaking mountain is from _anything_. And after even that "short" time the stuff is not very radioactive any more, and most of that little is alpha radiation. Piece of _PAPER_ is enough to stop that, so no harm done unless you go and eat some of it, or grind it to dust and try to inhale that.

After some time, it's more dangerous because it has lots of heavy metals, not because its nuclear waste.

Besides our descendants may just as well absolutely LOVE us for leaving them a good pile of energy. It's not like that "waste" is drained of all potential, it's just not economically feasible to reprocess it at the moment, but things change. If fusion doesn't for some reason take off just yet, and at some point most of easy uranium is mined, that junk is going to be a gold mine.

Re:Good idea for nuclear waste?

[barawn]

Found it (grr, it WAS the name that I thought it was). It's the Poynting-Robertson effect. With a time of 1 billion years in orbit, it's highly unlikely that it would actually fall into the Sun. It'd be struck by something first, which would, well, defeat the whole purpose of doing it. Even with a time of 1 million, it'd still be risky.

Re:Good idea for nuclear waste?

[barawn]

... and actually, to recomment, it's not entirely clear what would happen to an object just left in solar orbit, thanks to an effect on the next page after the Poynting-Robertson effect - the Yarkovsky effect. I should learn to finish reading before posting. Basically, the object will absorb energy from the Sun and reradiate it isotropically. Depending on the thermal properties and spin of the object, and its shape, this may push it inward, outward, or have no effect at all, and for large objects, will dominate over Poynting-Robertson and light pressure.

Granted, you should be able to allow this to push you inward rather than outward, especially once all constraints on shape are lifted with a space elevator.

Re:Good idea for nuclear waste?

[ajs]

"It's not engergy - it's angular momentum"

Uh... yeah...

Angular momentum is angular velocity times moment of inertia. It denotes a target, but not a means. In order to apply angular momentum you must to work (which is to say we must insert energy into the system).

Hence my comments.

"You need some way of generating thrust to counteract that momentum so you can fall easily."

Ugh... that's a real bastardization of the forces involved. Let's state that more clearly: there are a number of vectors involved, and you need to alter the sum of those vectors so that your new trajectory intersects the sun.

"If you want something that doesn't require propellant"

Why would you not want propellant? I was just suggesting that you'd get the energy from the sun, not that you wouldn't involve components from the earth in your drive. Ion drives using a solar-fueled fusion engine have been on the theoretical drawing boards for a long time, but AFAIK no one has put a whole lot of work into testing them. That might be the way to go. There are several electrical mechanisms that have been proposed as well, but they all involve some sort of propellant.

Then there's the ground-based laser idea, but even that could be powered by the sun.

The point is that getting into orbit cheaply and safely eliminates a huge portion of the constraint that makes space-based nuclear waste disposal less than attractive.

Re:Good idea for nuclear waste?

[ajs]

Yes, you are correct. There's also enough uranium in the atmosphere right now to kill everyone with cancer.

The question is what is your 2 pounds of plutonium going to do and how well can you contain it. You basically cannot answer those questions when you're talking about launching a rocket into space. If you're instead talking about lifting it into orbit via this system, you can begin to understand the failure modes and prepare for them. You can build a containment system that will keep it from dispersing.

If that containment fails, then you have to retrieve it from the bottom of the ocean. You'll get most of it back, but some small amount will be lost in the ocean floor and an even smaller amount will be lost in the ocean.

I think you can risk a couple of grams of plutonium in the ocean. What you can't risk is sending two pounds up in a rocket that could explode in the atmosphere. That could be bad in the ghostbusters sense....

Re:Good idea for nuclear waste?

[barawn]

Actually, there's a big difference between needing to insert energy into a system and needing to shift the angular momentum of a system. Energy is a scalar, not a vector: you could remove energy from the system by simply firing a rocket radially away from the Sun. That wouldn't work, obviously: you'd be in a hyperbolic orbit and out into the Solar System in no time. If you need to apply energy in a specific direction, then you're talking about a momentum shift, not an energy shift.

Getting energy from the Sun is easy. It radiates energy, you absorb it, boom, you've got energy. However, it's radiating outward, and so you don't have an easy way to remove the momentum of the system. You've got tons of power, but very litle momentum (you've got E/c momentum, but c is a very big number, even if E is quite large) so in general you're going to have to bring something along to generate that momentum (rockets - that is, throwing some mass out the back).

Personally, I don't think it's a bastard description at all. The fact is that all momentum from the Sun is coming out radially, and it's very weak - it's the flux of energy from the Sun divided by the speed of light. You could use a solar sail, but the amount of thrust is very small (at Earth orbit, it's 5 uN/m^2. This is really tiny, especially for something that's likely going to be tens of thousands of kilograms). If you want to fall into the sun, you need to get rid of the angular momentum that you have - you need to apply that energy against your orbit, which is not easy.

Let me put it this way. The Sun puts out something like 1500 W/m^2 at Earth orbit. Something at Earth orbit has ~ 450 MJ/kg of mass of kinetic energy. Naively you'd say that using the Sun's energy, you should be able to fall into the sun (with 1 m^2 radiator, and gathering all the energy in one burst at Earth orbit - so this is a worst case scenario) in 83 hours/kg. The truth, however, is that you can't use all of the Sun's energy to deorbit you, since you need to remove the momentum as well (that is, there is no way to directly convert the energy of the Sun into something directly pushing against your orbit - solar sails are the closest you can come) Anyway, what I'm basically trying to say is that the statement that "it just takes energy, and we've got the Sun!" is naive, as the situation is more complicated than that. For comparison, by the way, the same naive assumptions with the solar sail method would yield 190 years/kg. Yes, this is not the correct answer, since the solar flux goes as 1/r^2, but the 1/r^2 factor would appear in both calculations, so the scale is correct). You might use the sun's energy to power some engine on board, but you're not going to use it alone to remove momentum, so you've got to bring propellant along.

To put it simply, without a space elevator to the Sun, going to the Sun is more about momentum more than it is about energy.

But, anyway. Next point...

You don't want something with propellant because with propellant, you've just radically increased your costs. You're now throwing away useful material as well as useless material, plus, since you're talking about waste disposal, it'd require a lot of propellant. If you bury it somewhere on Earth, you're wouldn't need that, so it will always win out. The huge constraints on space-based waste disposal into the Sun is that it is resource and money intensive to do it, and the space elevator only eliminates a small portion of that constraint, not all of it.

Remember that time is money, literally. The longer it takes to shove this thing into the Sun, the better off you would have been putting it somewhere else - because it's cheaper. The Moon idea, for instance: nuclear waste could be sent to the Moon almost for free with a space elevator, at the right time of the month (twice, actually - it might actually be free, I'd have to think about the dynamics of it). Focus on the fact that we're talking about throwing garbage into the Sun, not anywhere else. The Sun has fundamental problems associated with it that other objects don't have, so you need to compare it with space-based disposal to other objects (or, in the ultimate act of arrogance, just chuck it out of the ecliptic). Is the benefit of permanent elimination really worth the huge extra cost? No, not really.

Think about it this way: imagine if the stuff was already in orbit, and you wanted to get rid of it. Deorbiting it into the Sun is not easy - it will require time, effort, propellant, and money. Anywhere else can be done for free comparitively. Therefore, dumping waste into the Sun is never going to happen. They'd be more likely to chuck it into Jupiter, or Venus, or something. Once you're in orbit, you'd still hate to go to the Sun, and would much rather go anywhere else. Hence, to conclude, the space elevator will not remove the main problem with space based disposal into the sun of nuclear waste (unless, as someone else put it, the elevator is 10x the distance to the Moon).

Re:Good idea for nuclear waste?

[ajs]

This is slashdot. I'm not going to take 2 hours to write up a response to your post. However, suffice to say that at every step in your argument I see one of two things: misdirection (e.g. energy isn't a vector, in response to my assertion that you could apply the given energy along a vector of your chosing) or unfounded assumptions (e.g. time==money with no explanation of why taking 6 years to lob your waste into the Sun is more expensive than taking 6 months).

Try stating what you have to say in 2 paragraphs, and tightening up the logic on those two.

Re:Good idea for nuclear waste?

[barawn]

in response to my assertion that you could apply the given energy along a vector of your chosing

I addressed this: this breaks conservation of momentum. It's not that simple. In order to use the energy that the Sun gives you to deorbit a vessel, you need to either a) redirect the (incredibly weak) momentum from the Sun against your orbit, or b) use propellant. Solar-powered propellant (the ion drive you mentioned, plus its many derivatives) is still very weak compared to actual conventional rockets, and they would take quite a bit of time to deorbit the object.

e.g. time==money with no explanation of why taking 6 years to lob your waste into the Sun is more expensive than taking 6 months

Sorry, this was covered in a previous post as well, and I thought it was to you. Apparently not...

Space isn't empty, and we don't have the ability to model gravity and track all of the objects in the solar system and predict things out several years in advance. Therefore, if you take 6 years (and it would likely be closer to several hundred years! it takes 5 years to get to Mercury by conventional means, and that's a light spacecraft, as opposed to a garbage scow) to deorbit something into the Sun, you need to pay someone to constantly check up on its orbit to make sure that something hasn't happened to sling it back at you, or somewhere else you don't want to go. There's simply no way around this yet, and there likely won't be for some time to come.

(And when it does come, then that will be the scientific advance that allows us to toss waste into the Sun, not the space elevator.)

People need to read the FAQ...

[agilen]

http://www.highliftsystems.com/faq.html

This talks about what will happen if it falls, what terrorists can do to it, etc. It actually seems fairly honestly done, not all marketing-speak.

Re:People need to read the FAQ...

[Peyna]

Where did they find a place with no high winds, hurricanes, tornados, or lightning? And, with ocean front property? I think I want to live there.

Re:People need to read the FAQ...

[mikeboone]

This was an interesting FAQ. Now I think we should make predictions as to its location, based on what they described:

• Unaffected by hurricanes
• Receives little or no lightning
• If it breaks, the lower portion falls into the ocean
• The anchor station will be an unlikely target to terrorists due to its isolation
• Not in the path of any existing launch "programs"

Re:People need to read the FAQ...

[mcfiddish]

I assume it would be over the equator; otherwise it wouldn't be in geostationary orbit.

Re:People need to read the FAQ...

[Aceticon]

It's anchored in a floating platform in the middle of the Pacific ocean.

When do i get my prize?

Re:People need to read the FAQ...

[Anonymous Coward]

No fair! You read the web site.

Re:People need to read the FAQ...

[PainKilleR-CE]

Where did they find a place with no high winds, hurricanes, tornados, or lightning? And, with ocean front property? I think I want to live there.


From the sound of it, about 400 miles from nowhere in the middle of the ocean...

Re:People need to read the FAQ...

[Oculus Habent]

South Pole

Land's cheap; taxes are low; heating costs are high.

Re:People need to read the FAQ...

[Ralph Wiggam]

And the oil industry is already quite experienced at building gigantic platforms and getting them out into the middle of the ocean. If those engineers have not been involved in these discussions, they should be.

-B

Re:People need to read the FAQ...

[Anonymous Coward]

All you have to do to protect it from terrorists is have a statue of Allah on the top.

Re:People need to read the FAQ...

[Tablizer]

(* All you have to do to protect it from terrorists is have a statue of Allah on the top. *)

Woudn't stop "redneck" terrorists like Tim McVey nor Irish Republic.

Terrorists come in all shapes and sizes. EOE.

Re:People need to read the FAQ...

[Tablizer]

(* "Will an oscillation bring the ribbon down?"
There will be a 7 hour natural frequency which can be actively damped with the anchor station. *)

The worlds largest bass guitar. Cool!

Twang twang katwaaaang....

Re:People need to read the FAQ...

[nitehawk214]

Actually Hughes (the owner of DirectTV) has an old floating drilling platform they tow out to the equator from California to launch geosynch satalites from. Its easier to get to that orbit from the equator so they save money on the rocket.

wow...

[bsDaemon]

a whole $570,000. I know that's all it would take to put a man on Mars. I bet they'll have a whole lot of change left over since all they're doing is building a space elivator.

Re:wow...

[thnmnt]

Consider then that Pfizer spends $4.7 billion dollars a year getting earthbound objects to 'elevate' into space. Why not just give them licensing rights for a Viagra elevator, stick Bob Dole on it for the maiden voyage and have the whole thing sorted in a year?

Re:wow...

[Anonymous Coward]

*shudder*

"Viagra", "Bob Dole", and "maiden" should never appear in the same sentence...

it just seems so fragile

[jedie]

doesn't it? An accident might be disasterous with objects of this size.
And not everybody would be too happy with it being built, (I think) it would be very easy to sabotage this.

I would love to see it become operational though..
(Or perhaps they should rather invest those billions of dollars in quantum teleportation? :))

Comment removed

[account_deleted]

Comment removed based on user account deletion

Cheap

[brejc8]

I think it was AC Clarke who said that it would be about $100 to get someone into space and about $50 for a return journey.
This does blow your average $1 million for a five day rocket based space holiday out of the water.

Re:Cheap

[Anonymous Coward]

Need I remind the parent's author that the work of AC Clarke is FICTION??

Re:Cheap

[kalidasa]

I think it was AC Clarke who said that it would be about $100 to get someone into space and about $50 for a return journey.

Yes, but wasn't that in 1979 dollars?

Re:Cheap

[brejc8]

These figures were based on scientifical research.

Re:Cheap

[Dyolf Knip]

Hell yeah. With a beanstalk, orbital launch costs go from "being chauffered from LA to New York in a solid gold limo with diamond hubcaps" down to about normal air freight charges.

Oh, well..

[olman]

I like space stories as much as the next person. However, this one reads like a company sales spiel more than a serious initiative. And everyone shoulds know what "within 10-20 years" really means, no? That's how much longer to fusion it's been for quite a few decades. And it's still 10-20 years from commercial applications.

No matter, this nano-material they're plugging should be quite useful for a few real-life applications right now. If there's no "well, you see.." about it somewhere.

Re:Oh, well..

[scott1853]

I thought nanotubes were discussed awhile ago and the consensus was that they couldn't easily be produced in significant quantities in a reasonable amount of time.

short circuit

[the_Bionic_lemming]

I seem to remember someone commenting that a space elevator would act like a bridge between the ionosphere and the earth - Making a giant "short circuit" - does anyone have a link to the article that was posted?

Re:short circuit

[the_Bionic_lemming]

I saw that too - But I was referring to the Ionosphre being Highly charged, and us essentially putting a conductive wire from that charged area and attaching to - well - the ground.

I nosed around in the archives looking for the post where someone had linked a paper discussing the possibility of having a large Zapping sound as the Ionosphere was grounded.

offtopic linux (debian) question

[Anonymous Coward]

I'm trying to install debian, i have 3 cds that i downloaded. I'm installing it on my other PC that isn't able to boot CD-ROMs, so I want a floppy that will let me install from the cdrom. I've done this with other distros easily, they always included boot.img or something similar, but i cant find that for debian ANYWHERE (cds, web, ftp sites)

I've tried using what I could find, root.bin which doesnt work at all, and rescue.bin which boots but isn't for installing and it panics when it cant find a ram drive or something.

Where the hell can I get the boot.img (or whatever) for debian??

Re:offtopic linux (debian) question

[Anonymous Coward]

just get rid of that ancient POS compooooter and get something more modern, you will be happier than fiddling with ancient hardware, and forget debian it is crapware for wannabe hackers...

get a real distro like Slackware or if you just want to slam a distro in a machine and forget about it go with either Redhat or Mandrake...

Re:offtopic linux (debian) question

[Anonymous Coward]

first off, ive used slackware. second, its an old pc in my room, that i never use, so i want to install linux on it, my main pc is 1.6ghz and fine, and it runs the best OS ever, winxp... now someone help me install debian

Re:offtopic linux (debian) question

[cculianu]

Why debian tho? Debina is crap.. it doesn't get updated nearly enough. They are always like months behind the other distros in terms of software newness.

Get gentoo if you feel like compiling everything and you have an internet connection.. otherwise go with something else like mandrake or redhat... they have floppy installers I think.

Re:offtopic linux (debian) question

[Anonymous Coward]

Walmart, $299. It comes pre-installed

Very Unlikely

[dduardo]

It seems to me that this project will never work. There are to many forces at play. The elevator would probable snap in half do to all the strain. If we did manage to build it there would be a HUGE problem: Earth's rotation would slow down, forcing us toward the Sun. Imagine the Earth as an ice skater in rotation. The person keeps their arms close to their body to rotate fast. What happens when the person's arms raise away from their body? They slow down. It is a simple concept of centripetal acceleration. The elevator would act as an arm of the Earth, thus causing it to slow down.

Re:Very Unlikely

[onion2k]

Woah. I hope they hire you as a consultant. I'm sure none of these things will have occured to them at all.

Actually.. knowing NASA..

Re:Very Unlikely

[perfects]

Even if it did cause the Earth's rotation on its axis to slow (by an incredibly small amount) that would not affect the Earth's orbit around the sun in any way.

Re:Very Unlikely

[zloppy303]

This effect is caused by the redistribution of the mass of the rotating body (de arms are relocated), I don't think the mass of the elevator will be anything significant in relation to the mass of the rotating earth.

Re:Very Unlikely

[Anonymous Coward]

Probably would snap, but I don't think we have to worry about Earth slowing down.

Angular momentum of a 1,000,000 kg object at the end (100,000 km) of the cord -> less than 10^10 kg.m/s

Earth's angular momentum (just from spin) -> about 6 x 10^33 kg.m/s

Re:Very Unlikely

[Anonymous Coward]

Yes, I suppose it would very slightly reduce the rate of rotation of the earth (as putting anything into orbit from the earth's surface by any means must do). It only slows the rate of rotation of the earth around its axis (the poles). It doesn't slow the earths orbit around the sun.

Re:Very Unlikely

[Anonymous Coward]

The Earth's rotation would indeed slow down... but not by very much! The earth has a mass of 6e24kg. How much mass would the elevator have?

Area = 100 000km * 1m = 1e8 m^2
Density = 100g/m^2 (like paper? probably lighter)
Mass = 1e7 kg (10 000 metric tonnes)

So the earth would be about 1e17 times heavier than it's "arm".

Re:Very Unlikely

[Anonymous Coward]

There are to many forces at play. The elevator would probable snap in half do to all the strain

Gee, I'll bet the scientists and engineers who are designing this thing never thought of that. Heck, they were just going to slap that baby up without doing any calculations whatsoever!

The elevator would act as an arm of the Earth, thus causing it to slow down.

Next time, take the physics class that involves actual numbers. It might give you a fee for orders of magnitude.

Re:Very Unlikely

[dbrutus]

Space elevator slowing down the earth's rotation?

Hey! I always wanted to fit more time into a day, now here's my chance.

Re:Very Unlikely

[Dyolf Knip]

The day is getting longer all by itself. This _might_ speed up the slowdown by a few percent, up to a whopping 5 milliseconds per day per century.

Re:Very Unlikely

[Squiffy]

Ai, ai, ai... People! The parent post is a troll! Ignore it!

Re:War is bad for children and other living things

[Anonymous Coward]

The current state of the economy exists mostly independent of who the president is.

The original NIAC paper

[MarvinMouse]

This idea originally came from NASA's institute for advanced concepts.

There are a lot of funky stuff going on there. But, here's the original space elevator paper. I personally thought it was an interesting read.

Re:The original NIAC paper

[Amazing Quantum Man]

Wrong. The original Space Elevator idea was by Yuri Artusanov (sp)? Clarke gave him credit, and the paper you referenced also has Artusanov in the references. He invented the concept around 1960.

Re:The original NIAC paper

[MarvinMouse]

Okay, I will try to rephrase my statement a bit.

Not the original paper that explains Space Elevators, but more correctly, the main paper that got NASA actually moving on the project.

Does that sound better?

Problem.

[teamhasnoi]

...and believe this will not be a problem but we are conducting studies to make sure this isn't a problem. Since we are aware of the possible problems now we can design the elevator to avoid these problems.

Houston, I think we have a problem.

another 1st ...

[Anonymous Coward]

I want to be the first a$$hole that bangs the sh*t outta some slut on that thing!

Re:another 1st ...

[Foss]

The first to join the thousand mile high club?

Re:another 1st ...

[virg_mattes]

Based on your comment, even if you're no the first to have sex on this thing, you're certainly likely to be the first asshole to do it.

Virg

Re:another 1st ...

[spike hay]

I don't think anybody reading slashdot, myself included, will ever join the thousand mile high club.

beam me up

[crea5e]

"Scotty one to beam up."

"I'm doing the best I can captain but the elevator is stuck on floor 3."

Re:beam me up

[Anonymous Coward]

I wonder how many floors it would be to get to the top?

Atmospheric Conductivity Issues

[Uttles]

Mr. Laine said the material, expected to be highly conductive and 30 times stronger than steel, is not yet in production...

Highly Conductive... the article also states that they are looking for a region of the planet for the anchor where storms and high winds are uncommon. I'm not so sure this is going to eliminate any risks. It seems to me they are going to have to develop this thing so that it can withstand being struck by lightning many, many times. A perfect solution would be something that could actually store and use the power generated by multiple lightning strikes.

My point is just that we don't really know everything about lightning, and just assuming that because there aren't many storms in the region the cable will not get struck doesn't seem smart to me. A highly conductive lightning rod extending into space seems to me something that would attract electricity, no matter what the weather conditions. I'm just picturing something like a Van de Graaf generator attracting all the loose electrons in the area. They need to develop the system so that it accepts lightning and other electric charges and distributes them somehow, causing no damage, even while cargo is in transit.

Re:Atmospheric Conductivity Issues

[UncleOzzy]

A perfect solution would be something that could actually store and use the power generated by multiple lightning strikes.

No problem. Doc Brown did that way back in 1955.

Re:Atmospheric Conductivity Issues

[Anonymous Coward]

In one sense, it should rarely be struck by lightning. It is grounding the clouds itself, so electrons will simply flow in whichever direction they feel like without having to ionize the atmosphere (aka lightning) So yes there will be a current, and maybe even small lightning "sparks" from nearby clouds (i don't know why or if this would happen but i couldn't rule it out) but if it is highly conductive there should be no problem, because the voltage across the elevator should be very small even if the current is large. That means the wattage is low, and low heat, etc. No problems!

Re:Atmospheric Conductivity Issues

[doug_wyatt]

If it is conductive, then it will act just like a lightning rod, but not in the way you imply. Contrary to popular opinion, lightning rods keep lightning from happening near them by slowly bleeding off the charge differential - NOT by having the lightning hit them instead of surrounding object. A really tall conductive cable would allow charge build-up in the clouds to be discharged before it reached "lightning-proportions".

Taking this to an extreme, if we turned the Earth into a porcuipine of really tall lightning rods, we could theoretically eradicate lightning all together. Wow. A new cause to unite around.

Re:Atmospheric Conductivity Issues

[Uttles]

Ah, I see. Well, like I said, I don't know all that much about lightning. I just hope this highly conductive material won't have problems with high electricity loads.

Re:Atmospheric Conductivity Issues

[Eightlines]

Why not use the static energy gathered from the atmosphere to power the elevator? From previous space elevator programs I've heard on the radio (CBC.ca and search for Quirks and Quarks) they were planning on using lasers to propell the device. And from what I recall MIT had developed a tin foil airplane that could be propelled by laser. (This was possibly linked from /.) Combine the technologies and you could have an entire structure that self generates its own propulsion.

Re:Atmospheric Conductivity Issues

[Eightlines]

Sorry for the additional post. Here's the Quirks and Quarks link: http://www.radio.cbc.ca/programs/quirks/archives.h tm Space Elevators is November 3 2001.

Re:Atmospheric Conductivity Issues

[Anonymous Coward]

IIRC, passing a conductor through a changing magnetic field will induce the movement of electrons in the conductor. The ribbon will be geosynchronous, but the sun distorts the earth's magnetic field, so that in essence, this elevator will be a huge generator. Even with no lightning strikes, there will be a lot of energy to contend with.

Re:Atmospheric Conductivity Issues

[Orgasmatron]

Highly Conductive paths to ground usually tend to prevent lightning by bleeding the potential out of the air before it builds to the point of arcing.

Re:Atmospheric Conductivity Issues

[Anonymous Coward]

So long as it is properly grounded, there won't be a problem. However, finding a stable electrical ground in the ocean doesn't sound easy to me. If it isn't grounded correctly, it will act as a magnent for lightning as you feared.

Re:Great news, but

[Anonymous Coward]

South Africa is nowhere near the equator.

Impact on the environment (and the ground)

[Christopher Thomas]

Also what about the risk of it falling down? An orbital tower will wrap about the earth more than once if it falls. The description in Red Mars was particularly though provoking.

I used to think that this would make space elevators impractically dangerous. However, this turns out not to be the case.

The energy gained by the falling cable will be at most its gravitational potential energy, which is within a factor of two of conventional high explosives (per unit weight). Pick a maximum yield on impact, and you have a maximum cable weight. Use a thin enough cable to meet this weight restriction, and you have an adequately disaster-proof elevator (it'll make a mess, but not wreck the world's climate).

My own calculations with a 10 kT yield/cable weight came up with something that could reasonably be used for space travel and would pay for itself if you could keep the cargo moving.

The biggest problem is figuring out how to move cargo fast enough. I'd be leery of having induction motors mess with the cable itself, and if its a nanotube bundle they won't conduct in the right direction anyways. Winches are much too slow. Sheathing the cable with metal would only be practical for a very thin layer, which ends up being too thin to support the required currents without boiling off (I think). It's an interesting design problem.

Re:Impact on the environment (and the ground)

[zbuffered]

The biggest problem is figuring out how to move cargo fast enough.

I say use compressed air. Pressurize below the cargo and let it shoot up the elevator. You could use any power source you wanted to power the air compressors. And if that weren't enough, the elevator "car" could also have wheel-type-things, so that it could climb up the elevator.

What are the chances that whatever the elevator was tied to out in space would throw Earth's orbit off, ever-so-slightly? Would this affect us in any major way?

Re:Impact on the environment (and the ground)

[Anonymous Coward]

I say use compressed air. Pressurize below the cargo and let it shoot up the elevator.

Possibly Better yet, if the entire length of the elevator were airtight, put the air compressor in the "car", create a vacuum above, and pressurize below. Of course, the car would need a very long extension cord!

Re:Impact on the environment (and the ground)

[Anonymous Coward]

The cargo lifters are powered by lasers firing from the platform at photovoltaic cells on the lifter.

Re:Impact on the environment (and the ground)

[zbuffered]

The article describes the "elevator" as:
a 100,000-kilometre-long ribbon about one metre wide with the thickness of a sheet of paper

So there goes the air-tight theory...

Re:Impact on the environment (and the ground)

[MindStalker]

multiple cables and counterweights?

Re:Impact on the environment (and the ground)

[PMuse]

The energy gained by the falling cable will be at most its gravitational potential energy, which is within a factor of two of conventional high explosives (per unit weight).

There is also rotational energy to deal with, but I don't think this will elevate the total energy out of the range you're discussing.

As an aside, in terms of force on impact, the F=dP/dt, or the change in momentum when the cable strikes the surface. This is why the dorce imparted is so much worse than merely the weight of the cable.

Re:Impact on the environment (and the ground)

[mberman]

According to the article, the power source is a laser shot from the platform, aimed at collectors on the bottom of the car. There, it's converted to electricity, and drives motors with wheels on the cable. Since intertia should keep the cable perfectly straight, it seems like a really good use of laser-powered propulsion.

Re:Impact on the environment (and the ground)

[tuxedo-steve]

I'd be leery of having induction motors mess with the cable itself, and if its a nanotube bundle they won't conduct in the right direction anyways.

I come home from a Trek marathon, and I'm subjected to this.

Eugh, it's too early. :)

Re:Impact on the environment (and the ground)

[sgtsanity]

One of the most interesting proposals that I've heard is to always launch two payloads at the same time: one going up, and the other going down. That way it would theoretically use no energy. I'm not quite sure about the engineering of such a solution, though.

Re:Impact on the environment (and the ground)

[fuzzywig]

easy, use the motor that grips the cable to brake as it comes down (you'll need to do this any way, or, splat!), this will generate electricity. Either store this in battries or do the oposite of the way up and beam it down for collection.

Re:Impact on the environment (and the ground)

[GigsVT]

Pick a maximum yield on impact, and you have a maximum cable weight. Use a thin enough cable to meet this weight restriction, and you have an adequately disaster-proof elevator (it'll make a mess, but not wreck the world's climate).

Have you been asleep the last year? People got all uptight because a few thousand people died in some falling buildings, and you think the world would accept a space elevator "making a mess" by destroying a huge swath

Re:Impact on the environment (and the ground)

[cybercuzco]

Cable safety is really a bugbear. The only part of the cable that will fall towards earth is the part below the point of breakage. In a worst case scenario, this is at Geosynch orbit. But what most people fail to realize is that as the cable falls it speeds up just like any other falling object. 60 or so Km up the cable is falling fast enough to burn up completely on reentry. So only 60 km or less of cable reaches the ground even in a worst case breakage scenario. The plan that highlift talks about puts it in the middle of the pacific ocean, convieniently 60 km or more from anything that might be damaged by a falling cable.

Re:Impact on the environment (and the ground)

[Anonymous Coward]

How the Hell did this get Mod'd as insightful? If Mr. Thomas had bothered to read the linked material he would know that all of this is discussed in the white paper.

Go read the material. Learn where you're wrong.

Re:Impact on the environment (and the ground)

[Guppy06]

"The energy gained by the falling cable will be at most its gravitational potential energy,"

Isn't that cute... but it's WRONG!

The top of the cable has something much more powerful acting on it than gravity alone: the bottom of the cable. The top will be moving just as fast as the bottom, accellerating downward just as much as the bottom. So you have a miles-high structure coming towards the earth at a relatively steady 9.8 m/s/s. This is far worse than mere gravity alone.

Re:Impact on the environment (and the ground)

[shess]

It's not going to be for free, if only because most of your mass is being sent up there for a reason (ie, you send the satellite into orbit, you slingshot the Mars mission to Mars, etc).

In fact, when you come down to it, with this system it probably costs as much to bring stuff down (in a controlled fashion) as to take it up, so you would want to minimize how much to bring back. Maybe delicate things like results from zero-G experiments, or people, ride the elevator back down, while other items might be ejected to reenter in more traditional fashion (if the cost of carrying the heat shield up is cheaper than the cost of carrying the payload down).

Re:Impact on the environment (and the ground)

[RobertFisher]

Your argument is flawed on two accounts.

First, the weight of the elevator is already set by structural constraints. Static equlibrium demands that a point at the bottom of the elevator must support the weight of the entire elevator above it.

Second, taking a "per kilo" weight analysis is totally bogus when evaluating the total damage. The total weight of the elevator (set by static constraints, not by your analysis) will be absolutely huge, and so the total damage will vastly exceed any conventional or even nuclear device.

Bob

Re:Impact on the environment (and the ground)

[Enigma2175]

the power source is a laser shot from the platform, aimed at collectors on the bottom of the car. There, it's converted to electricity, and drives motors with wheels on the cable.

That is an idiotic design. If you use conventional conductors in the cable, then we can also use the cable as a big powerline from space. We can have a large solar array in space and get the power back to earth via the elevator cable. Proposals in the past for powering earth from space have suggested using microwave transmission, the elevator cable would be a much safer alternative. In addition, if you have a powered cable you can use energy return brakes on the climber, so when it comes back down the motors function as generators, returning power to the system. With the aforementioned solar array, the elevator can be an energy producer rather than an energy consumer. Not to mention the fact that it is terribly inefficient to convert the electricity to light (laser) then back to electricity on the climber. It would be much more efficient to run power in the cable itself.

Re:Impact on the environment (and the ground)

[p4k]

That is an idiotic design. If you use conventional conductors in the cable, then we can also use the cable as a big powerline from space.

I suggest you try calculating the resistance of a cable of 2 mm2 cross-sectional area and 36000km long - you might find transmission losses would be a little high. As in you'd be hard pushed to measure *any* power at the other end at all.

Re:Impact on the environment (and the ground)

[Jack Brennan]

RTFA

They're planning on building it in the middle of the Pacific, not Manhatten island.

I suppose it could kill some whales or something...

Re:Impact on the environment (and the ground)

[GigsVT]

It would be long enough to fall onto land, no matter what ocean you put it in.

Re:Impact on the environment (and the ground)

[Jack Brennan]

OK, it's long enough, but I have a hard time believing that a 1m wide x .1mm thick ribbon, fighting air resistance on the way down, could devastate a huge swath of anything. Ever drop a sheet of cardboard off a high-rise? There's not a whole lot of energy left in it by the time it hits the ground.

Re:Impact on the environment (and the ground)

[s0l0m0n]

Carbon nanotubes==incredibly strong.

I don't think that it should be too much trouble to piggy back a maglev rail to the ribbon, then top the ladder with a large solar array. Heck, if you design the station at the top right, you could use the rail to launch stuff way out into space, instead of just getting it to the top of the tower.

Affixing the rail to the ladder might be a bit difficult, as I suspect that punching bolts or rivets through the ribbon would seriously damage its structural integrity, but that's just an engineering problem.

josh

Re:Impact on the environment (and the ground)

[Tablizer]

The biggest problem is figuring out how to move cargo fast enough. I'd be leery of having induction motors mess with the cable itself, and if its a nanotube bundle they won't conduct in the right direction anyways. Winches are much too slow. Sheathing the cable with metal would only be practical for a very thin layer, which ends up being too thin to support the required currents without boiling off (I think). It's an interesting design problem.

I got a solution: Use rocket engines. In fact, skip the cable and just use the rocket engines alone! I am sure scientists can find a way to keep them pointed stable enough for flight.

Wait a minute......

Re:Impact on the environment (and the ground)

[flygeek]

The proposed ribbon would be only a few millimeters thick, and about a meter wide. Such a cable would tend to either burn up due to air friction, or decelerate dramatically due to atmospheric drag. Besides, even if air resistance didn't appreciably decelerate the cable, you can't treat the impact solely on the basis of kinetic energy of the total mass. It's the energy density generated by the impact that matters the most. An asteroid generates an enormous amount of energy in a confined space because a huge mass hits all at one place. A falling space elevator cable might take days to fall, depending on where it broke, and the impact energy would be spread over hundreds or thousands of miles, so the total impact on any one place is not out of reason (although I still wouldn't necessarily want to get hit by it).

Re:Impact on the environment (and the ground)

[pclinger]

Ok, so it won't destroy the climate, but it still falls and hits everything in its way on earth causing mass destruction on thos places. But its OK, right?

Re:Impact on the environment (and the ground)

[Macadamizer]

No, that IS mere gravity alone -- where do you think the 9.8 m/s^2 acceleration comes from anyway?

Re:Impact on the environment (and the ground)

[spike hay]

Farthur in the future, I see no reason why you can't make an airtight cylindrical one.

Re:Impact on the environment (and the ground)

[spike hay]

EVERYONE!! THIS IS AS THIN AS A SHEET OF PAPER!!!

Use your heads. Do you think a sheet of paper will cause planet-wide destruction!!!

Re:Impact on the environment (and the ground)

[coryboehne]

If advances are made in superconducting materials then it may be possible... however you are correct that copper is a poor idea.

Re:Impact on the environment (and the ground)

[Christopher Thomas]

According to the article, the power source is a laser shot from the platform, aimed at collectors on the bottom of the car. There, it's converted to electricity, and drives motors with wheels on the cable. Since intertia should keep the cable perfectly straight, it seems like a really good use of laser-powered propulsion.

The problem's not power. The problem is that your cargo has to move on the order of Mach 3 or better in order to get a decent rate of transport (remember, with a 10,000 ton cable you can only have, say 2000 tons of cargo on the cable at any given time).

You're not going to climb at that speed with wheels. A practical cable would also be about as thick as your finger, so wheels would be a bit tricky at anything faster than a slow crawl.

In the simplest case, you could just send power through the cable itself (nanotubes conduct extremely well; have two cables next to each other, and there you go).

It's the rate of cargo transport that limits the cost-effectiveness of a space elevator. You have to amortize the cost of the elevator over a relatively small maintenance window. The more cargo you can ship, the less you have to charge per kilo, and the more likely it is you'll actually find enough customers to transport the amount of cargo you need.

Re:Impact on the environment (and the ground)

[Christopher Thomas]

Cable safety is really a bugbear. The only part of the cable that will fall towards earth is the part below the point of breakage. In a worst case scenario, this is at Geosynch orbit. But what most people fail to realize is that as the cable falls it speeds up just like any other falling object. 60 or so Km up the cable is falling fast enough to burn up completely on reentry. So only 60 km or less of cable reaches the ground even in a worst case breakage scenario.

I'm playing Devil's Advocate in assuming that the energy would be concentrated in one place. If you assume a more diffuse distribution, then you just look at recent volcanic eruptions to pick a maximum energy/mass release into the atmosphere. In practice this would pretty much allow as large a cable as you want.

I feel more comfortable assuming an impossibly bad worst-case scenario, though (force of habit; I'm in engineering).

Re:Impact on the environment (and the ground)

[An Onerous Coward]

I think you're both wrong (responder more blatantly than the original poster).

Responder: 9.8 m/sec is the force exerted by gravity at sea level. By the time you get to the top of the cable (about 100,000 km away), the force being exerted is orders of magnitude smaller.

Original Posting Guy: You're correct that the top of the cable would be pulled on by the bottom of the cable, but it wouldn't be as bad as having the whole of the cable accelerating at 9.8 m/s/s. Remember that the acceleration of the bottom of the cable is being retarded by the inertia of the top of the cable, since the top isn't being subjected to as much gravity.

Personally, I think they ought to line the cable with explosives at periodic intervals, if the breaking of the cable is really a concern. Also, if it's made out of a dozen smaller cables instead of one large cable, the greater surface area might ensure that more of it burned up in the atmosphere.

Re:Impact on the environment (and the ground)

[Anonymous Coward]

Sure, it's long when it starts to fall.

Part that gets to ground is not long. The cable is thin, it burns in the atmosphere just like everything else moving fast enough.

Re:Impact on the environment (and the ground)

[GigsVT]

EVERYONE!! THIS IS AS THIN AS A SHEET OF PAPER!!!

Use your heads

Not to beat a dead horse, but if you have trouble convincing the Slashdot crowd, how do you think the general public would feel about this? Assume there really is no risk, now convince the public to let you build one of these in their back yard.

I still don't buy that there is no risk, even if it is paper thin and can cause no damage on its own. The whole idea is that you are going to be lofting very heavy objects without thrust systems, a breakage would mean that this thrust-less heavy equipment would also come hurtling down. I guess this could be mitigated by parachutes, but lets just say, this technology is going to be a hard sell.

Re:Impact on the environment (and the ground)

[spike hay]

The whole idea is that you are going to be lofting very heavy objects without thrust systems, a breakage would mean that this thrust-less heavy equipment would also come hurtling down.

You mean, they would come down just like a rocket if it failed?

The payloads would weigh much less than a fully fueled rocket.

Also, they would be launched from the middle of the pacific. So unlike Cape Canaveral, if the cable failed, the payload would just land in the ocean. If the payload was near GEO orbit and had close to orbital speed, it would just burn up in the atmosphere.

Also, structures just don't "fall down." This is engineered twice as strong as it needs to be. It cannot break during the worst hurricane.

Re:Impact on the environment (and the ground)

[Anonymous Coward]

> This is engineered twice as strong as it needs to be. It cannot break during the worst hurricane.

Untrue - the FAQ states a class 5 hurricane has strong enough winds to break it.

Re:Impact on the environment (and the ground)

[Anonymous Coward]

> Static equlibrium demands that a point at the bottom of the elevator must support the weight of the entire elevator above it.

Wrong - centripetal acceleration will mean there is a net force pulling *out* from the surface.

It's a ribbon, for heaven's sakes - did you really think it was going to be a rigid, self-supporting structure?

Re:Impact on the environment (and the ground)

[pediddle]

Who's talking about copper or any other (superconducting) material? The thing is made of carbon nanotubes.

Re:Impact on the environment (and the ground)

[coryboehne]

did you read the parent? No?... I really did'nt think so.......

fix my work elevator first, please

[Anonymous Coward]

dang thing sounds and feels like it is in its death throws. Even people who ride it all the time and put on that fake aire of confidence and conchalante attitude will often look worried. Its slow as hell too.

SlashSnot

[Anonymous Coward]

i think this idea is ridiculous, what a load of horseshit, it will never fly Orville, i wish these scientists would pull their head out of their collective ass' and start thinking about more plausible projects...

Re:SlashSnot

[Anonymous Coward]

I hate to admit it, but that use of "horseshit" still has me laughing.

Re:Great news, but

[Anonymous Coward]

Energy isn't the same as power. The energy needs may be the same, but it can spend the day climibing the cable. As they say, you could use the motor in an electric razor to move a tank up Mt. Everest with the right transmission (and ignoring friction & practicalities like that). Don't get the idea that I think it'll work, though.

And Puh-leeez don't start that anti-gravity crap again - I don't want to vomit into my keyboard.

Falling down - why does it not fall down?

[Anonymous Coward]

Could some1 please explain me why this "elevator" wont fall down. As we pull from the rope according to Newton we transfer momentum and so it should fall down, shouldn't it?

What am I not getting here?

Re:Falling down - why does it not fall down?

[spike hay]

Simple. The rope extends way past GEO orbit. The rope past GEO has tension on it because of centrifugal force. So if you have a rope that is 50,000 miles long, it will remain in tension.

Flashbulbs

[DavidLeblond]

Just don't take any pictures. If I remember correctly, they "fall down" pretty quick because they dislike having their pictures taken more than Sean Penn.

NO FLASH PHOTOGRAPHY

[jolshefsky]

Hopefully they're planning to put up a big sign that says, " NO FLASH PHOTOGRAPHY ." I bet the second picture you take would look pretty cool, too.

Re:NO FLASH PHOTOGRAPHY

[SecGreen]

In other news, the Department of Homeland Security is pressuring congress to pass a law which outlaws flashbulbs because they could be used by terrorists to cause mass destruction...

Re:NO FLASH PHOTOGRAPHY

[ceejayoz]

However, only the single-walled variety of nanotubes catch fire. Those with multiple walls do not explode - the researchers are unsure why.

is it just me...

[Drunken_Jackass]

...or wouldn't you have to locate the anchor point to be at a location that makes sense for the "drop off" point of the satellites to establish a useful orbit?

Why wouldn't we have a bunch of satellites in the same planar orbit?

I'm assuming that the elevator gives the sats a ride up, and then simply releases them. Is there another release mechanism that "points" the satellite in the right direction?

Also, could you use the elevator for geosynchronous orbit birds?

Re:is it just me...

[vidarh]

If you release the satellite in orbit, then boosting it into another orbit is "cheap" compared to getting it up into orbit in the first place. Many satellites have booster rockets anyway to give them some maneuverability.

Re:is it just me...

[The Fun Guy]

The real cost in orbital maneuvering is getting into orbit in the first place. If the lift cost goes from $10,000/kg to $100/kg, it would be worth it to get dropped off at a less convenient position, and adjust the orbit as needed. Remember, just because you used the elevator to get off Earth doesn't mean you have to leave the rockets at home. Hauling a bunch of attitude adjustment fuel wouldn't be a big deal at those cheap lift prices.

For that matter, if getting the sats from the elevator to their proper orbits becomes a common problem, you could have a fleet of high-orbit unmanned vehicles whose sole job would be to take satellites off the elevator and ferry them to where the are supposed to go, more or less, and let the sats handle just their own fine tuning once they're in place.

Re:is it just me...

[Koyaanisqatsi]

Nearly all satellites have propulsion systems to get them to the right orbit and to correct it every now and then. When that fuel is over, after several years, the orbit can no longer be corrected and the satellite begins a slow descend back to earth.

As for getting different satellites on different orbits, its really just a matter of releasing them at the right altitude and then using the (already in place) propulsion system to make the necessary corrections. As it is done today.

Re:is it just me...

[Anonymous Coward]

Ah - actually, out there (geo) we tend to move them higher up and further out whewn we're running out of fuel.

Re:Great news, but

[Anonymous Coward]

amazing what one can gather from the article... Unlike the science fiction version, this space elevator need not be anchored improbably both to Earth and an asteroid.

Instead, it would be tethered just to Earth from a floating platform in the equatorial Pacific Ocean.

From there, a 100,000-kilometre-long ribbon about one metre wide with the thickness of a sheet of paper would be propelled by rockets beyond the point in space where orbiting objects remain above a fixed point on the Earth's surface, the so-called geosynchronous orbit.

The elevator would be kept in place by the competing forces of gravity at the lower end of the shaft, and, at the far end, outward acceleration.

Think About It

[virg_mattes]

Um, getting down from orbit has never posed many problems. We on Earth call that "falling" and the trick isn't getting down, it's getting down slow enough not to vaporize one's arse. In more serious terms, no, it's not likely that anyone will ever use the elevator to reenter Earth's atmosphere. Most likely, if anything needs to come back down in one piece, they'll lift a reentry module with the elevator and then let it drop with the precious payload the old fashioned way.

Virg

Re:Think About It

[Amazing Quantum Man]

Why would they do that? Why not use that enormous gravitational potential energy, and convert it to a storable form on the way down?

Sure, it's not 100% efficient, but you still have some energy that you can use for the next upward trip.

Re:Think About It

[dbrutus]

Actually, I think it would be much more likely that loaded return trips would be made. Why haul around all that expensive re-entry weight when you have the perfect mechanism to come back down on the elevator itself. It's elegant, it's cheaper, and it's likely to be much less riskier than re-entry which can and has gone wrong in the past.

Re:Think About It

[virg_mattes]

> Why haul around all that expensive re-entry weight when you have the perfect mechanism to come back down on the elevator itself.

I can think of two reasons, although neither of them is a complete show stopper. First, until more than one ribbon is up, while something comes down, nothing can go up. It's faster to deorbit and reenter by falling, because the next cargo lift can happen concurrently. Second, lowering is harder (not much, admittedly, but still somewhat) than lifting because of the anchor point on the ground and the direction of the gravity well. For now at least, it'll still be cheaper to lift a reentry module for return trips, keeping in mind that (at least early on) much more stuff is going to go up than down.

In the long term, I think we'll find that your solution will get more feasible eventually.

Virg

Re:Think About It

[mestar]

At the geosynchronous orbit you can move to any other point on that orbit in a simple way. An easy push will do. Just be careful not to hit any satellites.

So, you can build two elevators, one for going up, and another one for going down. Trains/cars/vehicles could easily be transported from one to the other. This way you could have bandwidth limited only by the cable strength.

Also, that spot at the cable in the geoshnchronous orbit would be a perfect for a space station, which would easily grow because it is cheap to send new modules up. You can build hotels and houses there! I guess you could even suspend an electricity cable on the ribbon.

This would really be great.

Re:Think About It

[dbrutus]

I don't think that anybody is looking at one unitary ribbon to run an elevator but more like several ribbons running an elevator bank. The acceleration profile for an elevator would permit grandma to see orbit. I don't see grandma making splashdown or, more importantly passing the training regimen for doing so.

It's worth running a bank if you can make things (like monocrystal jet turbine blades) worth the return trip.

15 years - yeah right

[ryanvm]

Sounds great and all - but 15 years? Yeah right. I'm still waiting on flying cars, jetpacks, and robotic sex slaves. (Oh wait - I don't think that last one was on the Jetsons.)

Re:15 years - yeah right

[ceejayoz]

...robotic sex slaves. (Oh wait - I don't think that last one was on the Jetsons.)

Maybe Rosie... wait, bad image.

Re:15 years - yeah right

[spike hay]

Sounds great and all - but 15 years? Yeah right. I'm still waiting on flying cars, jetpacks, and robotic sex slaves.

I doubt in 15 years, yes. We have the technology to do lots of stuff right now or within 5 years. In fact, we already know how to build nuclear detonation engines that can send people to the outer planets or slow missions to the stars. We did that with Project Orion in the 60's. (If NASA really worked on it, we could have the tech to do a manned Satrun mission in 5 years with the non-nuclear VASIMR engine.)

Uhm...

[Dark Lord Seth]

Is it in any existing flight paths?
One of the nice things about our anchor site is that it is in the middle of nowhere, approximately 400 miles from shipping or plane routes.

So how are they going to get stuff over there? Drive it through the middle of nowhere on a truck? I'm pretty sure equatorial conditions (high temp, high humidity) aren't the best thing that could happen to any satelite or other object bound for space. Besides, wouldn't a nice 20 Billion USD worth satelite be a nice target to attack? Once simple ambush with a 100 USD rocket launcher and poof goes 20 billion bucks. Are they going to provide every transport military cover all the way to the anchor site? Same thing applies to shipping and I don't think airplanes would be allowed near the anchor site... How do they intend to secure it all?

Are they going to set up massive defences at the anchor site? SAM batteries against air attacks? Will they station ground forces at the anchor station? If so, who will provide these forces? The US goverment? NASA? ESA? Or an independent body?

Also, suppose it all does work out after all, how are we going to deal with things in space? Is everybody going to do his thing or are we going to learn from history and immediatly develop some standards for cargo storage up there like container size, weight and capabilities?

Re:Uhm...

[Anonymous Coward]

Since the thing is to be anchored in the middle of the pacific ocean I'd imagine that the US Navy would handle the job of defence.

Re:Uhm...

[Wirr]

Drive it through the middle of nowhere on a truck? Gosh, you mean like shipping German cars like Mercedes, VW and Porsches to the US, you're right, that's unheard of. There is no means to accomplish this.

I'm pretty sure equatorial conditions (high temp, high humidity) aren't the best thing that could happen to any satelite or other object bound for space.

Yes, those conditions are really forbidding. That would be as if the NASA would Launch their satellites from Florida, say e.g. Cape Canaveral.
Or if the ESA would launch there satellites from Guinea, say e.g. Kourou.

Re:Uhm...

[Julian352]

If you read the article, you would have seened that it is stationed in middle of ocean on a platform. It is very similar to the current position of another launching method. (launching from floating platform in middle of ocean. There were many stories about it, search ./) Thus the transportation is already non-issue as it was solved for the conventional launching. As for defence, you have billions of dollars worth of oil going without any escort, I think a satelite can do that as well.

Why would you even need that much defence. If you read their FAQ, they said that destruction of cable will result in minimal damage. And hitting a ship on the way there could be done already as many US satelites are launched from Europe, etc.

Re:Uhm...

[checkyoulater]

Besides, wouldn't a nice 20 Billion USD worth satelite be a nice target to attack? Once simple ambush with a 100 USD rocket launcher and poof goes 20 billion bucks. Are they going to provide every transport military cover all the way to the anchor site?

Following your logic, how come the Space Shuttle hasn't been attacked on the slow journey from the vehicle assembly plant to the launch pad? Doesn't it take a few days? If you would read the faqs, it mentions security risks. The ultimate plan is for this to be a multinational project. Allowing the entire world access to something will most definately lower the risk of a terrorist attack. If the usual enemies of the Western world are allowed access to the Space Elevator, they might not see it as a symbol of American repression. Perhaps it can be seen as a symbol of International unity?

Yes, I realise all that sounds like Science Fiction, but perhaps this Space Elevator is the first step towards the Enlightened future we all crave so much.

Re:Uhm...

[MystikPhish]

First, launching from the sea has been and IS being done now. In fact if you bother to read the Highlift website summary, you'll note that Sea Launch is the basis for the tether platform. I'm not aware of any extraordinary security taken for Sea Launch that wouldn't otherwise be taken for high value items.

As for defending it from attacks, well... This is a 1 METER wide ribbon, that's going to be about as thick as a sheet of paper.
In the middle of the ocean.
Design to withstand meteor impacts.
Do you think someone is just going to walk over and cut it down with a hacksaw? Or shoot it? Crash into it? And the worst thing you could POSSIBLY do to the ribbon is knock off a few miles of it. The rest is still in space, probably with many miles of reserve ribbon for repairs etc. ready to be lowered and have it fixed in a few months...

Losing a few miles probably won't even be that big of a deal considiering the minor percentage amount of mass that would be lost. I'm sure they'll have some mobile counter weights on the end that can just be reeled in to compensate, until the new ribbon is deployed.

Re:Uhm...

[Anonymous Coward]

Yeah, and then all of the terrorists can join hands and dance around the space elevator singing camp songs.

Anon

Re:Uhm...

[patiwat]

>> One of the nice things about our anchor site is that it is in the middle of nowhere, approximately 400 miles from shipping or plane routes.

> So how are they going to get stuff over there?

By boat of course. The earth platform would be in the middle of the ocean. This isn't particularly difficult: Boeing Sea Launch alredy ships satellites from Seal Beach, CA down to the equator for launches. Arianespace ships satellites and launch vehicle components via boat to the ESA's French Guyana launch facility.

> wouldn't a nice 20 Billion USD worth satelite be a nice target to attack?

No satellite ever made has cost $20B. The original Hubble cost less than a billion, and no ISS component cost more than a billion.

Re:Great news, but

[mikeplokta]

Check an atlas.

The equator passes through northern Brazil, some distance from the main Amazon basin. It also passes through Colombia and (obviously enough) Ecuador.

It goes way north of South Africa, and actually passes through about six different countries in Africa -- none of them models of political stability, admittedly.

There are also parts of Indonesia and Kiribati on the equator.

Live free or die my ass

[Anonymous Coward]

VA and IBM are taking different directions. VA, whose roots lie in the open-source world of Linux, is trying to move more toward proprietary software in an effort to boost its revenue. Meanwhile, IBM, which earns considerable revenue from licensing its patents and from selling proprietary software such as DB2 and WebSphere, is embracing open-source projects such as Linux and Apache.

http://news.com.com/2100-1001-949505.html?tag=fd _t op

NASA has given money???

[Anonymous Coward]

Hmm.. NASA has given money? ..but where does NASA get it's money? The TAXPAYERS pay it, yeah! They are the ones who pay again! I'm sick and tired of taxpayers money being wasted on something like this. If we can't live peacefully on this tiny planet do you think we would live peacefully in space?

Re:NASA has given money???

[ThereIsNoSporkNeo]

Who wants to live peacefully in space?
I think we should outfit every space-bound ship with the 10 kW laser from an earlier slashdot article. Live peacefully. Bah.

Re:Great news, but

[Anonymous Coward]

There are no NEO objects strong enough to support hanging an elevator from.

they dont propose hanging it from anything. Instead they will use the competing forces of gravity at the lower end and outward centripetal acceleration at the farther end keep the ribbon under tension and stationary over a single position on Earth.

Not to mention the fact that the engine to lift the elevator car has to put out the same energy that a rocket engine does (conservation of energy, heard of it?).

The amount of energy may be the same, but it will be expended in a much safer manner.

Even assuming these issues could be magically fixed somehow, we have the socio-political issues. In order to be geosynchronous it has to be over the equator. Which is either in the ocean, in South Africa or in the middle of the Amazon.

An ocean-going platform based on the current Sea Launch program would be used for the Earth anchor and located in the equatorial Pacific.

All of this information is easily available at the High Lift Systems web site. You should check it out. It's a good read and it sounds like you're interested in the subject.

Research

[virg_mattes]

> Check an atlas.

Check the article. The phrases "floating platform" and "equatorial Pacific Ocean" are prominently featured.

Virg

Security.....

[Bush_man10]

Me and my friends around the office have been talking today about the whole sept 11th event and terrorist attacks in general in Europe and NA this morning. My point is how would they secure this 10 billion dollar investment? If this ribbon is attacked by a plane 1 km up in the air how would they stop it? Also if the ribbon is cut would they be able to fix it or would they ahve to replace all of it?

I think it's a great idea to build but at the same time how do you protect something so big?

Re:Security.....

[dbrutus]

Well, once you get it up once, you just stock a few spares in orbit at $100/kg so when (not if, it'll eventually happen) the ribbon gets cut, you just have to drop down one of the spares to re-establish the elevator. It's only the first one which will be expensive all subsequent ones will drop in price substantially.

I expect that you'll protect it like they protect everything else, a bunch of guys with guns will shoot you if you break out of certain paramaters.

Re:Great news, but

[R2.0]

South Africa? What map are you looking at?

Huge eysore? So was the Eifel Tower. Now the French can't live w/o it.

Exploiting? Lets see - huge amounts of the highest tech material on the planet being shipped thru and fabricated in Africa. Sounds like thie ticket to bring Africa OUT of exploitation.

I'm glad you weren't around when some really smart monkeys started breaking rocks to make tools - "It will never work - your using up all our resources of flint, and we'll upset rthe balance of power with the neighboring tribes."

Size and Composition

[virg_mattes]

They covered this on the web site. It will carry a current, but it's in the range of milliwatts because of the size and makeup of the ribbon. The comment was based on using a cable (like an Earthbound elevator) and so doesn't really apply here.

Virg

Re:Size and Composition

[Anonymous Coward]

maybe im not up on the 'new units', but isnt current in amperes?

$570,000???

[Pig Hogger]

$570,000???
Isn't that a wee-bit expensive for a dog-eared copy of Fountains of Paradises ????

Elevator!

[wackybrit]

Their FAQ has some great questions.

How easy would it be to break?
What if it falls?
How will the elevator be funded?
What will the elevator be used for?
When can I ride it?

Which leads me to..

Well, sir, there's nothing on Earth like a genuine, bonafide, electrified, six-car space elevator!

Elevator! Elevator! What's it called? Elevator! Elevator!

Miss Hoover: I hear those things are awfully loud.
Lanley: It glides as softly as a cloud.
Apu: is there a chance the track could bend?
Lanley: Not on your life, my Hindu friend.
Barney: What about us brain- dead slobs?
Lanley: You'll all be given cushy jobs.
Abe: Were you sent here by the devil?
Lanley: No, good sir, I'm on the level.
Chief Wiggum: The ring came off my pudding can.
Lanley: Take my pen knife, my good man!
I swear it's Springfield's only choice!
Throw up your hands and raise your voice!
Everyone: Monorail!
Lanley: What's it called?
Everyone: Monorail!
Lanley: Once again!
Everyone: Monorail!
Marge: But Main Street's still all cracked and broken!
Bart: Sorry, Mom, the mob has spoken!
Everyone: Monorail! Monorail! Monorail!
Homer: Mono- DOH!!

Dad are we there yet?

[gelfling]

Hey you kids sit down and behave before I come back there.

Daaaad I gotta peee

You should have gone before we left now you'll jut have to wait.

Re:Great news, but

[bmcneil]

At least one of these technical objections is pretty much dead wrong. Kinetic energy at the bottom of Earth's gravity well is not equal to the potential energy achieved when a rocket reaches orbit; much energy has been lost to drag by the atmosphere on the way up. (Space elevator sled moves in the hundreds of kilometers/hour, rocket at thousands, drag grows as square of velocity, etc...)

Much bigger problem with the argument that energy required is equal: the rocket carries its fuel all the way up, whereas the sled's fuel lives at the bottom of the cable in a nuclear reactor or other electrical power plant, then is transmitted up via laser beam (according to the article) or maybe through the cable. Given how much of the Shuttle's mass is fuel at takeoff (I don't feel like getting great stats, but to give you an idea, the SRBs burn 5 tons of fuel per second), this gives us huge energy savings on lifting payloads with the elevator.

The other technical concerns are engineering problems, and I'm going to throw in with the optimists on those. (What's more wild-eyed...putting a big, strong rack in orbit, or negating gravity?) And as far as the political concerns go, I guess that's why there aren't any multinational manufacturing concerns in those poor equitorial countries, right?

My favourite part of the FAQ

[GothChip]

How will the elevator be funded?
The elevator can be funded privately, publicly, or with a combination of the two.

In other words "We don't know".

Re:My favourite part of the FAQ

[dbrutus]

Frankly, who cares how it gets funded before they even are sure of the engineering. If you can drop launch costs to $100/kg from $10,000/kg, that's a savings of $9,900 per kilogram and an investment by the satellite companies of a slightly smaller amount would still leave them ahead on a net basis.

Then you have all the impractical uses that become practical at some point between $10k and $100 per kilo. Let's take power transmission satellites which become practical at $200/kg. A company that wants to loft one of those babies up would be willing to invest almost $100/kg in the creation of the elevator because the investment dollars dumped in that project would still leave his power satellites practical on a net basis.

The money will be coming out of the woodwork for this *if* it gets to the point of floating a stock or bond offering.

Hmm I can see an interest in extreme sports...

[Anonymous Coward]

Can anyone see some guy with a parachute and suction cup shoes and gloves climbing up this ribbon to do some base jumping?.. well of course it would be difficult to get up very high but heck I'd almost try it. And since its a carbon based ribbon its probably very smooth so it wouldn't be hard to make suction cups hold onto it.

Re:Just dont take a picture!

[InOverMyFeet]

I was just remembering this story. I had an mpeg on my harddrive of carbon nanotubes going up in smoke after a flash. You know people are going to want to take pictures on the 4 hour ride up to space.

Good thing I learned this trick...

[thelinuxking]

Now I won't have to wait for all the other people in other layers of the atmosphere...for I know this: http://eeggs.com/items/12697.html

The Web Between Worlds

[StarEmperor]

Charles Sheffield's novel _The Web Between Worlds_ is a fictional account of the construction of such a "beanstalk." It's strong on the science and is a pretty good read.

A Miasma of Bad Science

[virg_mattes]

> It seems to me that this project will never work. There are to many forces at play. The elevator would probable snap in half do to all the strain. If we did manage to build it there would be a HUGE problem: Earth's rotation would slow down, forcing us toward the Sun. Imagine the Earth as an ice skater in rotation. The person keeps their arms close to their body to rotate fast. What happens when the person's arms raise away from their body? They slow down. It is a simple concept of centripetal acceleration. The elevator would act as an arm of the Earth, thus causing it to slow down.

Wow. There are so many scale errors here it's hard to tell where to start. First, What strain exactly would "snap the elevator in half"? It's a ribbon, and while it's certainly possible to break the ribbon, it's not likely to happen under normal operation, and the design specifies that they'll set it up in a location that minimizes the likelihood of high winds or lightning. Second, "Earth's rotation would slow down"?!? You can't be serious with this. The mass of this thing is so much less than that of the Earth that the slowdown would be indetectable with the most sensitive instruments we have, if we were actively looking for it. To take your example of the figure skater, imagine her spinning, then letting out a one inch long piece of the finest hair you can find. How much do you think she'll slow down? And last, why exactly would slowing Earth's rotation cause us to head for the Sun? The day would get to be more than twenty-four hours, but the speed the Earth moves around the Sun (that's "revolution", not "rotation") would not change in the least.

Go buy a book on physics.

Virg

Re:A Miasma of Bad Science

[Jeppe Salvesen]

Uhm. Would it really slow down the rotation at all? I mean - it would be in geo-stationary orbit. Do I need to buy a book on physics, too? (Not afraid to do so if required).

Re:A Miasma of Bad Science

[hiroko]

> The day would get to be more than twenty-four hours That could be handy - when do we start?

Re:A Miasma of Bad Science

[spitzak]

Yes I think it would slow down, by an infintesimal amount, if you assumme the cable is made out of mass that used to lie on the surface of the earth. I'm not sure what would happen if the counterweight or cable were made from mass that was not part of earth (such as an asteroid), though. Anybody know?

Re:A Miasma of Bad Science

[pestihl]

WOOT WOOT longer days.. no more working at nights.

Even though man can not detect it, I think mother nature would. Being that our weather patterns are chaoticly sensitive to the breath of a butterfly.

-nasu

Re:A Miasma of Bad Science

[Anonymous Coward]

This is really splitting hairs due to its irrelevance. Technically, extending the ribbon would slow the earth's rotation by a redicuously small amount. If there were a counterweight in orbit, then connecting it to the ribbon would not have any effect on the earth's rotational speed. BTW, the earth's rotation is already slowing down on the order of 1 second per year every 100 or 200 years (ie, the day 100 years ago was 1/365 seconds shorter).

Re:A Miasma of Bad Science

[timeOday]

That's why I never get out of bed. Don't want to slow down the earth by standing up.

Re:A Miasma of Bad Science

[univeralifepadre]

thanks for clearing this up for those of us that are physics impaired. even newton's cannon makes my brain hurt.

they need to get their costs right

[pangu]

From their website,

For the initial space elevator these recurring costs combined with repaying the initial capital investment would give us total launch costs of $100/kg ($230/lb or 1/10 to 1/100 of conventional systems)

So it's $100/kg, which works out to $230/lb. I see... looks like the same math that caused a recent failed mars mission.

Re:they need to get their costs right

[Myco]

Well, you see, metric is cheaper...

Alternatively... as you get things farther up, they will weigh less but have the same mass. So a pound at the top of the elevator has more mass, and if the cost is based on mass then you'd expect this sort of effect when calculating cost.

It's fair, but uninformative.

[Ted_Green]

"What if lighting strikes it?

The best way to deal with lightning is to avoid it hence the proposed location of the ribbon is in an area that receives little to no lightning."

That's a pretty good impersonation of a political waffel. Answering the question by avoiding it.

Re:It's fair, but uninformative.

[dillon_rinker]

There are Pacific islands that have no thunderstorms. The native cultures do not have a word for lightning. But yeah, before I ride up in this thing, I want to know what happens if it's hit by lightning...

Re:It's fair, but uninformative.

[Jeremi]

It's true that they waffled there... but if lightning does strike the ribbon, wouldn't the energy just conduct harmlessly into the ground? Seems like it would just be an extra-large lightning rod that way.

Re:Great news, but

[LBU.Zorro]

Where to begin???

Point 1: Neo to attach to. Unnecessary. You can achieve the same thing with a really long teather and a 1 kg weight on the end. Did you not notice that the cable was 100,000 km long, when geosynch orbit is only 36,000 (miles or km I can't remember, but even if it is miles that would make it 57odd thousand km up, far less then the 100,00 required) the extra thousands of km are used to provide leverage and a decent ratio for the mass to be lifted.
Although I am curious to know what you mean by strong enough. All you need to do is get an object, in geosych orbit, move it to an outer orbit but keep it at the same angular velocity (how long it takes to orbit the earth) and the resulting centripetal force can be used to pull against when pulling up mass. 'Strong' neos aren't needed, a collection of cotton wool would do it, if there was enough and it was far enough out.

Point 2: Constant height. Not actually necessary, the water level is pretty flat (aside from tidal variations due to the moon and the sun) BUT the cable is under constant tension thus would forgive a certain amount of play. In fact the cable has to be at over 5 tonnes of tension at the base to be able to lift the mass required.

Point 3: Energy required for lift. Actually you are wrong again, the energy required is less. When you use a reaction engine fully half the energy required to boost you is wasted throwing mass out in the opposite direction. HOWEVER along with this is the fact that they are going to be using lasers to drive photovoltaic cells to drive electrical motors, and this could (in theory) be purely sunlight driven.

Point 4. Location. The ocean isn't too bad, a simple cargo ship deliver the cargo and it lifts. Sure its not rail or lorry but its good enough. Most of the oil the US needs is shipped via tankers, why can't a few satelites?

Point 5. Anti-gravity. (Ignoring the racist angle) this is an unproven experiment, and it should be noted that 2% is a little different to lifting the item into orbit.

As an aside, the cable itself will weigh in at a stunning 750 tonnes. Of that 480 tonnes (metric) will be above geo-synch orbit (assuming 36k km or should that be Mm???) and not likely to crash down.

I applaude them, but hope it does all work even though I have my doubts...

The tensile strength of the cable needs to be huge.. 7.5 kg per km, and that needs to hold around 270 tonnes, its a hell of a challenge....

Z.

About red mars...

[jeti]

Many /. readers seem to think of the catastrophical fall of the space elevator cable in the 'Red Mars' novel.
The book described the cable as being 10m in diameter. I always thought of this being ludicrous.
Look at the FAQ. It talks about a ribbon 1cm wide.

Re:About red mars...

[jeti]

Mhmm - the width seems to vary quite a bit.
It's only 1cm wide below 10km altitute.

"The ribbon of our proposed 20,000 kg capacity elevator will have a 2 square millimeter cross-sectional area, be 1 meter wide and microns thick on average."

Re:Great news, but

[LMCBoy]

Read the article, Genius.

1. There's no NEO tether at the other end; rather, the cable stretches out thousands of km beyond the geosynch point.

2. It's attached to a floating platform in the middle of the Pacific Ocean.

3. South Africa...whatever. Check your atlas.

4. Energy. A space elevator would be far more efficient than a rocket, so yes, Virginia, it would use much less energy.

5. Real-time adjustment of earth end: no idea what you're talking about here. The weight of the cable counterbalancing the bouyancy of the submerged portion of the platform would keep the platform stable. This is how all boats float.

That catapult idea again.

[uncoveror]

Mechanical climbers, powered by an electric motor, would scale the ribbon, hauling the cargo thousands of kilometres before catapulting the payload, which could include anything from satellites to human passengers, to its destination.

NASA must be obsessed with catapults. Every plan they come out with seems to make use of one in some way.

Re:Great news, but

[Aceticon]

First of all, you have the technical issues. There are no NEO objects strong enough to support hanging an elevator from.

Read the article - it's not going to be tethered to anything on the space side. It's going to be kept in place by a combination of gravitational force on the Earth side and centrifugal force in the space side.

Computer control to keep the Earth end at a constant height (which essentially requires solving the n-body problem where n = several dozen) in real time is impossibly hard.

I'm sure the gravitational effect of Io will not be enought to distabilize a structure hold in place by centrifugal force (Want more centrifugal force? Make the line longer!!!)

Not to mention the fact that the engine to lift the elevator car has to put out the same energy that a rocket engine does (conservation of energy, heard of it?).

You sorta forgot that rockets go up with a lot of useless stuff that ends up falling down again - like fuel, 1st and 2nd stage engines, and basically most of the payload of the rocket at lift-off.

Also, and acording to the article (did i mention you should've read the article?), the lift will move cargo (and eventually passengers) at between 120 and 160 km/h.

Drag (which is a way of loosing energy - conservation of energy, remember?) is proporcional to speed. Any rocket trying to achieve low earth orbit will need to achieve a speed of around least 17,500 miles an hour (Space shuttle low orbit speed - http://seds.lpl.arizona.edu/ssa/docs/Space.Shuttle /general.shtml). That means that while still inside Earth's athmosphere the rocket will have to achieve a speed much bigger than 160 km/h which is a drag (pun intended).

Even assuming these issues could be magically fixed somehow, we have the socio-political issues. In order to be geosynchronous it has to be over the equator. Which is either in the ocean, in South Africa or in the middle of the Amazon. The ocean is inconvenient for mass transit on the elevator. The Amazon is needed for biodiversity. Which leaves South Africa--a political hotbed. Not that they'd want it--it'd be a huge eyesore, hovering on the horizon from hundreds of miles away. Even if we paid them to take it the PC crowd would say we were "exploiting the poor blacks" in SA.

The lift will be anchored to a floating platform in the middle of the Pacific ocean. (Did i mentioned that you should read the article?)

-----------------

I don't know who's worse - the author of this article or the moderator that rated it Interesting (at least it wasn't rated Insightful)

Orbital Power Plant

[lute3]

This kind of structure should be able to function as a power plant
in two or three different ways and send the power very efficiently
to earth down a wire (thus, solving any issues with microwave or
other space-to-Earth power transmission methods).

1) Unobstructed solar panels in space.

2) Natural magnetic induction from the Earth's magnetic field.
I don't know what the terminology for this is, but this concept
was explored recently with the use of a thin tether drug
behind a space shuttle. The difference in the magnetic field at
different locations of a conducter generates electricity.

3) Nuclear reactors are 'safer' in space.
There's *plenty* of radiation in space--a little more won't hurt

Re:Orbital Power Plant

[unDiWahn]

"2) Natural magnetic induction from the Earth's magnetic field.
I don't know what the terminology for this is, but this concept
was explored recently with the use of a thin tether drug
behind a space shuttle. The difference in the magnetic field at
different locations of a conducter generates electricity."

Not only does that sound... a little unbelievable in the context that I originally heard it, but if it _is_ applicable then you'd need to have it in a non-geosynchronous orbit, as it'd be the changing magnetic field that induces electricity. You can't just stick a magnet on a wire and "poof" you have electricity (I wish =] )

Re:Orbital Power Plant

[breadbot]

Unfortunately, as Edwards explains in his 80-page paper, a wire that long, even a gold one, would have resistance too high for feasible power transmission. I think you would need it to be superconducting.

Just asking for trouble...

[Tickenest]

Man, can you imagine how much time and money would be wasted the first time you get a jackass who pushes all the floor buttons on this puppy right as he's getting off?

Oh geeze...

[Thud457]

If this drops "launch" costs from $10,000 to $100, I think people can then afford to put maunevering thrusters on their damn satellites!

Actually, if launch costs did drop that much, this would turn the economics of satellites on its head. Right now, we put a lot of work into satellites to make the most of the mass we put into orbit. That translates into an enourmous $/lb ratio, that is, satellites are expensive. What happens when we don't need to maximize that? (Hmmm, I seem to recall that was a strong factor in the development of transitors and ICs. I guees this could actually be a negative change in some ways.)

Outward acceleration?

[Anonymous Coward]

The elevator would be kept in place by the competing forces of gravity at the lower end of the shaft, and, at the far end, outward acceleration.

Nothing is accelerating outward. If it did, the ribbon would be torn away from the Earth. In fact, being in circular motion, every point on the ribbon must be accelerating TOWARD the Earth -- otherwise it would continue in a straight line.

If the ribbon's centre of mass is beyond the point of geosynchronous orbit, then the gravitational force on it is not sufficient to keep the ribbon in an orbit with the required period. By anchoring the ribbon to the Earth, we provide enough additional INWARD force on the ribbon to prevent it escaping orbit.

(No, escaping orbit does NOT imply an outward acceleration. It simply implies insufficient inward acceleration to hold a body in circular motion.)

I don't buy it

[khendron]

I LOVE the idea of a space elevator. Reading "Fountain's of Paradise" is what got me into the engineering field in the first place.

However, I still do not buy the argument that getting into space will cost virtually nothing once a space elevator is built. Sure, in pure energy, the costs are low. But what about the entire support infrastructure?

Right not it would cost me about $100 to take the train from Ottawa to Toronto, a 4 hour trip. With a space elevator we are talking about a trip 100 times farther and 50 times longer. Applying some hand waving math, we would be looking at $10K to $20K for a trip up the elevator. Maintenance costs for the elevator are going to be a *lot* more than those for a strip of train track, so it would not be unreasonable to multiple this estimate by a factor of 10.

Yes, that is a lot less than $1,000,000 but also far from virtually nothing.

Re:I don't buy it

[dunedan]

ok, now lets divide by your weight. $10 per kilo, lets say you weight 60 kilos. this predicts 60 for your trip. Now lets point out that I can fly from DC to San francisco for about $100. A 5 hour trip but still the same price. Some transportation is just cheaper than others.

Babel?

[SecGreen]

Sounds like another great opportunity for a biblical smack-down.

Lightning

[incog8723]

From the FAQ: What if lightning strikes the ribbon? The best way to deal with lightning is to avoid it hence the proposed location of the ribbon is in an area that receives little to no lightning. This is why I always install lightning rods barefoot, sopping wet, with no gloves or clothes on, by a tree that just got struck by lightning.

Sounds familiar

[Hoi Polloi]

"this elevator could be a reality within 15 years."

Reminds me of all those "World of Tomorrow" movies from the 40s and 50's that said we'd all be driving flying cars right now and being served by humanoid robots. We didn't even get HAL in 2001!

Re:Sounds familiar

[rtaylor]

No reason we couldn't be driving flying cars now. Most of the tech is there, and if really wanted we could have figured out the rest.

That said, people have problems driving in 1 dimension (straight road). A good portion of drivers have problems with 2 dimensions (corners ;).

Could you imagine what would happen if they were in the air? Until we have computers to the point where they can fly in emergency situations with no assistance (we're very close -- I can think of 2 problem areas) we'll not have flying cars. The human factor isn't ready yet.

Re:Great news, but

[Anonymous Coward]

A couple nits to pic there.

1) The equator doesn't run through South Africa. The Tropic of Capricorn does, but only through the northern tip of the country. The equator runs through Gabon, the two Congos, Uganda, Kenya, and the southern tip of Somolia. Here's a map showing specifically where.

2) Who said the elevator had to be stationed along the equator? A geosynchronous location can be had anywhere over the surface of the globe. It just happens that many communication and weather sats happen to be geostationary due to their respective functions, not because an equatorial orbit is the only one that can provide relative imobility. Most of those political considerations suddenly become alot easier to work around when you've got 197,000,000 sq. miles to work with instead of 25,000 linear miles.

The author

[Anonymous Coward]

I'm going to give the moderator the benefit of the doubt that he knows that the equator doesn't run though South Africa, because the author sure doesn't. The Tropic of Capricorn does, but the equator doesn't.

Re:War is bad for children and other living things

[John Biggabooty]

It is all part of their plan to bring about the New World Order, A global network of totalitarian governments. When they create a global second great depression, they hope we will all be desparate enough to let them have "emergency powers". Phony wars and "terrorism" are also parts of the plot. The Ivy League's Skull and Bones society, and The Illuminati are behind it all. Here are some links to things they have already done to create the New World Order. http://www.uncoveror.com/fans.htm http://www.uncoveror.com/vchip.htm http://www.uncoveror.com/webcams.htm

Could someone please answer this?

[DahGhostfacedFiddlah]

I've always wondered this myself. The one solution I thought of is that the cable extends farther out than is necessary to simply hold it up, and the extra "force" (yes, I know, it's not) of being extended further would account for the moving elevator cars.

Is this anything nearing what's proposed?

Re:Could someone please answer this?

[LBU.Zorro]

Yes.

By the sounds of it there will be over 10 tonnes of tension on the base of the cable (twice the lift capacity at least), the weight of the floating platform will likely be in the tens of tonnes and easily counter balance this. The weight of the cable beyond geosynch orbit will provide this tension and that would mean that you could climb up it and the only change would be a reduction in the tension beneath you.. You could get away with having a large weight just beyond geosynch orbit, and in fact that would be how I would do it, since the centrifugal effect would mean that you would have a gravity of sorts.. Of course that means you'd need to put something up there or bring something into orbit.

The main use I can think of for this technology is power. Orbital power stations would be far more efficient and always on, but beaming that power down would be a nasty thing, nobody likes mile wide+ microwave beams, plus the realestate to recapture the huge beam is expensive. This orbital elevator could be used to pipe that power down to earth, and get re-distributed from there, and that would be a pollution free, cheap (after a while) way to power the earth. If it works I'd expect several larger scale projects to occur, likely land based.

As another point, mainly to the doomsayers about the cable breaking, the issue is where it will break.. if it breaks at the base it will simply leave the earth and not crash anywhere, only the bit below the break will fall to earth... The 'worst' case would be if it breaks at the geosynch point, then you have 36,000 km's of cable falling.. Luckily most of it would burn up, leaving only a small section (odd km of it) at the base to hit the sea.

Z.

Re:Could someone please answer this?

[DahGhostfacedFiddlah]

nobody likes mile wide+ microwave beams

Isn't there any way to apply magnifying-glass-and-ant technology so that the beam is only a meter or so across when it hits the earth? Or is there too much atmosphere to make that work?

Re:Could someone please answer this?

[LBU.Zorro]

Well you could, but there are reasons why this is a bad idea.

I think the exploding birds might cause an issue, and the chance of serious injury / death if something managed to reflect some of the energy, a metal fragment etc, or a plane was blown off course.... The reason the beam is so wide is to reduce the energy per metre squared to below safe levels, thus not hurting anything, BUT that increases the surface area needed to gather that same total energy.

Z.

Why?

[mcrbids]

Rockets are messy, dirty, expensive, and limiting. The average Joe will *NEVER* experience space if rockets are the only way.

However, with "sky hooks", it's not only pheasible, it's almost guaranteed!

Science advances most in areas where there's money to be made - witness cell phones, digital cameras, and 3D video cards.

You don't think that your average, middle-class guy wouldn't save up $10k or $20k to stay a week at the Hyatt - in space?!?

Hell yeah! No problem! Zero-G, floaty trinkets in the gift shop, etc.

There's MONEY TO BE MADE here... and by the time I'm an old fart (30 now) I hope this will be becoming everyday.

Of course, we can launch rockets to other planets like Venus and build hooks there, too. That's when serious colonization will begin.

-Ben

No, No, and more No

[SkyLeach]

"It's not feasible to send waste into the sun - take a look through a few astronomy texts and you'll see why."

I have, and all I see is practical problems with energy required for launch. The space elevator would be a good option, if people don't mind a relatively fragile cable carying really bad radioactive stuff up into our atmosphere.

"Basically the problem is that any object we lift from the Earth has energy, and angular momentum. If you want to hit the sun, and not just put it in a very eccentric orbit, you need to remove a lot of energy from the object, and the space elevator wouldn't help - it pulls you out of Earth's gravity well, not out of Earth's orbit. You'd require massive amounts of fuel to get it there."

Why? A space elevator (not this one, it's too small) most certainly can launch things completely out of earth orbit. The trick is, as you stated, angular momentum. Get enough momentum on the object and it will continue to move on out of earth's gravity well. The real problem is just reaching escape velocity, which could be as simple as a boost after the object is out of earth's atmosphere. The energy required to accelerate the launch object to escape velocity once it is out of the atmosphere is relatively small. The moon could also be used to slingshot objects towards the sun.

In addition, the object doesn't need to slow down, and the sun's gravity will be helping all the way. I don't really see a payload of depleted uranium being (relatively) difficult to get to the sun unless you care how fast it gets there. Who cares if it takes 100 years?

Re:No, No, and more No

[KernelHappy]

In addition, the object doesn't need to slow down, and the sun's gravity will be helping all the way. I don't really see a payload of depleted uranium being (relatively) difficult to get to the sun unless you care how fast it gets there. Who cares if it takes 100 years?

Who cares? WHO CARES? I CARE!

Do you know what hitting a 100 year old depleted uranium capsule will do to insurance rates? I'm guessing that the rates on my lunar cruiser will be high enough as is by the time I'm 127 years old.

Re:No, No, and more No

[Xaoswolf]

*quote from the future*

As reported in the Neo Tokyo Times, August 13, 2202.
In sad news today we are afraid we must report that nuclear weapons have been dropped New York. The explostion from the impact spread the harmfull materials over a 15 block radius.
While we are not sure where the materials are from, the Martian Confederate is a prime suspect. Retaliation seems iminant.

*end quote from the future*

So what happens when our calculations are off by just a little.
I like the idea of the sun as a giant incinerator, but I want to be sure that what we want burnt, doesn't just fly off into space, or worse, meet us at the other end of it's orbit.

Re:No, No, and more No

[barawn]

If you only saw launch problems, you didn't look enough. Most of them deal with this question and the basic answer isn't launch energy, it's removing the orbital energy that matters.

Launch only matters from Earth's perspective. From the Sun's perspective, you're still going 30 km/s. Even after the space elevator, you're still going 26 km/s. You've got to kill that energy somehow.

If you're going to be disposing of things, you want it to be cheap, right? If it's really expensive, then it's not going to be worth it - it's not THAT dangerous, and shoving it in some corner of Earth is better. We're talking about cost here: I never claimed it wasn't possible, I just claimed it wasn't feasible.

I don't think you quite understand what the problem is. Once you get out of the Earth's orbit, you've then got to get on an impact path with the Sun. This isn't easy! This is very very difficult, and it requires removing a lot of angular momentum. Slingshotting around the moon won't do it. That'll slow you down a BIT, but not much: you can figure out how much it will slow you down pretty easily.

30 KM/S. That's a lot of speed. After the elevator, you're 23.5 degrees out of the ecliptic, traveling at 26 km/s in the ecliptic, and 3 km/s out of the ecliptic. Your relative speed to the moon won't be huge - maybe 4 km/s - and so you'd need 5 SLINGSHOTS around the moon to kill off most of your orbital velocity. Plus you'd need people controlling those slingshots to make sure the orbit is right, which is a lot of money. Never mind the fact that you need to ditch that 3 km/s before you're too far out of the ecliptic for anything to help you at all.

Basically, the Sun's gravity is not helping, at all. The object's in orbit. Gravity's going to keep it in orbit, and not pull it closer to the Sun. You've got to do that, by eliminating its tangential velocity. And that's a hell of a lot of energy.

Bottom line: if it isn't cheap, it's not feasible, and it won't happen. And until you find a way to strip 30 km/s away from an object, it's not cheap. Slingshots, solar sails, and propellant are all expensive (either in materials or in manpower) and the elevator doesn't really help that much. Launch costs are only a portion of the equation here.

Re:No, No, and more No

[Mr.Intel]

Basically, the Sun's gravity is not helping, at all. The object's in orbit. Gravity's going to keep it in orbit, and not pull it closer to the Sun. You've got to do that, by eliminating its tangential velocity. And that's a hell of a lot of energy.

Keeping something in orbit is harder than knocking it down. Talk to any NASA engineer and they will say that it takes half the energy manpower and money to de-orbit anything. Granted we are talking about earth orbit, but the principle is the same. Sure you have 26-30km/s of orbital velocity. Big deal. You don't need to cut 100% of the speed to get a sun bound trash unit headed for impact. It didn't take exorbitent amounts of cash to send probes to Mercury or Venus or to insert SOHO in between the Sun and the Earth. Why would it be big bucks to go all the way to the Sun? Orbital mechanics isn't *that* hard. Slingshot off Venus and Mercury and you are almost there. Even if you put the stuff in a sub-Mercury orbit, it would burn up just as neatly. Piece of cake if you ask me.

The biggest cost has always been getting out of the Earth's gravity well. This elevator removes most of that cost. The rest is just academics.

Re:No, No, and more No

[barawn]

First, the principle is not the same. Keeping something in orbit with Earth is difficult only because the atmosphere tries to bring it down for LEO stuff, and for avoiding other craft. It is also ridiculously quicker to deorbit something that is a few km above your target as opposed to 1 AU above your target, and manpower and money are proportional to time - it would take ridiculously longer to deorbit something from the Sun - years, decades - and you'd have to have someone monitoring it the entire time. That's expensive - especially the monitoring part. The DSN is quite crowded.

Re: Mercury - It will take 5 years, and 3 gravity assists just to get to Mercury orbit. Mercury still has 60% of the orbital velocity that the Earth has, and still is very far from the Sun: 0.4 AU! It would take several more gravity assists and a VERY complicated orbit to get to the Sun. Remember: gravity assists aren't free. You still need to GET to the planet, and that takes fuel.

Re: Venus - see the Mercury argument.

Re: SOHO - SOHO is in the Earth-Sun L1 point. It's not very much closer to the Sun than the Earth is.

You're not understanding things if you think that you can just slingshot off of Venus or Mercury. Slingshotting doesn't work the way you think it does, and you can't always do it - you can only do it if your orbit is favorable with respect to their position, so you may only get a shot to do it once or twice a year. In addition, all you'll really do is remove from your orbital velocity whatever the respective velocity is wrt the planet you're slingshotting from. It would take probably around 8 or 9 gravity assists to get an orbit that would collide with the Sun, and a lot of burns and a lot of manpower to get those gravity assists correct.

Almost every sub-Mercury orbit you could do cheaply would be hyperbolic and throw the thing out of the solar system - if you're lucky. You're not understanding the costs of space flight if you don't understand that. Throwing something into the Sun is expensive. People lots smarter than you and me have looked into this, and the answer is always "it's too much."

Re:No, No, and more No

[Anonymous Coward]

Why would you need to ditch the out of ecliptic component of the velocity?

Re:No, No, and more No

[barawn]

If you're too far out of the ecliptic, you're not going to do much of a gravity assist, since you're not going to get too close to a planet, now are you?

It's interesting that someone else pointed out that you can choose launch times such that all the elevator's rotation is against the tangential velocity. That'll keep you in the ecliptic (mostly - there'll be a reaaallly small offset). However, if you're talking about gravity assists, those are planned orbits, and having a launch window of "twice a year" limits your ability to create an orbit with gravity assists.

stunned at the weight

[shren]

As an aside, the cable itself will weigh in at a stunning 750 tonnes.

Are you stunned it weighs so much or stunned it weighs so little? Newer SUVs almost weigh a ton, and if you stack 750 of them on top of each other you don't get anywhere near orbit.

Re:stunned at the weight

[LBU.Zorro]

Stunned that it weighs so little, especially when you consider that it has to have a tensile strength of at least 280 tonnes (at geosynch). Just to lift itself and cargo.

I looked into orbital tethers and sky-hooks a while ago, and the weight to strength ratio needed is massive. A metre of this stuff weighs in at 7.5 grams, and can hold 280 tonnes? Thats very strong. They may thicken it as the cable rises (since the greatest tension is held at the geosynch point) but they said it was only a few centimetres squared (at ground level).. I'm very impressed, but will be more so when you can see this tiny line shoot straight up.

Z.

Re:stunned at the weight

[ShavenYak]

Newer SUVs almost weigh a ton...

Dude, my Toyota Echo weighs a ton (2030lb, actually). There are SUV's weighing in at nearly four tons (Ford Excursion - 7700lb).

Base in the sky

[t_allardyce]

Wouldnt it be much better to have a cloud-base that was held up by ribbons. Then you wouldnt have to have one long ribbon, but say break it down into 3 or 4 shorter, more manageable ones. at an already high altitude, planes could land on it and drop off the cargo to be lifted up and you could even make a TV show involving string puppets and jet-fighter babes. You'd be able to fit more lifts in that could be working at the same time.

I dunno how you could put it up there - either build it on the ground and then lift it, or build it in space and then lower it.

Re:Base in the sky

[Dyolf Knip]

They build it by launching a large roll of very thin cable with the shuttle. That little cable gets used to pull progressively larger ones up, much like using a string to pull a thick wire through wall conduit. Conversely, you could build the whole thing in space and then just lower it into the correct orbit, but...

The sectional approach is rather clever, but to be of any use safety-wise, the stations would have to be able to hold their own in the wierd altitude/velocity combo they'd have to have. After all, the only place on a beanstalk moving at true orbital velocity is at geosynchronous; everything else stays in place because its counterpart on the other side of the midpoint keeps balances it.

Here's an idea; concentric, spoked Ringworlds! Build a dozen ringworlds at varying distances from Earth's surface. Each would stay in orbit no matter how fast or slow they rotated. So we spin them up so that they all have the same angular velocity, and then connect them with nanotube elevators. It'd be a fairly rigidly defined structure, and any one piece of the spoke could break and it wouldn't affect the rest.

I'm imagining the first ring sitting just a few klicks off the ground. What a wild sight that would be!

What about the Coriolis force ?

[Anonymous Coward]

If I know my physics, an object crawling up the elevator's nanotube sheet would exert a (sideways) Coriolis force against it. Now, the nanotube sheet is very lightweight. Wouldnt this Coriolis force throw it out of orbit? How do they plan to counterbalance it ?

stay tuned

[Anonymous Coward]

.."NEXT on the History Channel, Disasters of the 21st Century".

Old idea with problems.. but promising..

[ldopa1]

The space elevator has been featured in a lot of books, most recently David Gerrold's "Jumping off the Planet".

This is a great idea, but it has one big problem. It isn't energy - The idea of generating energy by dangling something into the atmosphere from space has been explored and proven that it will work.

The problem is this: With every gram of matter you chuck into space (or even lift from the surface), the rotation of the Earth slows in direct proportion to the cargo's mass relative to the mass of the Earth. In other words, every time we throw something in to space,the Earth will slow down just a bit, no matter how small the load. Proving yet again that there's no such thing as a free lunch.

Fine, you say. It'll take a TREMENDOUS amount of mass to be lifted into space to stop the rotation of the Earth. I completely agree. However, if the Earth slows .000001%, (about 9 hundredths of a second, enough to win/lose a car race) then the days will get measurably longer unless we bring an equal amount of mass down.

Just to sate your curiosity, the earth weighs about 5.98 X 10^24 kilograms (or, 5,980,000,000,000,000,000,000 tons, metric, roughly speaking. Source.). That said, it would just take us lifting 59,800,000,000,000 trillion tons into space to affect the aforementioned change. Again, a tremendous amount, right?

Consider this: New York city alone produces 13,000 tons of residential waste a DAY, and they've run out of places to put it (Again, Source). That's 4.7 Million tons a year. And they're currently paying PA to dump is for them. There are other cities with the same problem. Exactly how long do you think it will take for someone to decide to move the waste even farther away? Like Space? And that's just residential.

That's only one example. Let's add Yucca Mountain's 77,000 Metric tons of waste and 100,000,000 gallons of high level radioactive waste water (Call Claire at the Yucca Mountain Project (dept. of civilian radioactive waste mgmt. for more info -Link or 1-(800) 225-6972). Okay, lets add the "extra" garbage of all of the other states, countries, provinces etc who have run out of places to put their waste. It adds up REALLY quickly.

And that's not including the actual mass of the elevator itself, including it's anchor.

Mind you, I still think we should build it, I just don't think we should use it as a tool to get rid of our problems that's we're too stupid to fix, but smart enough to move out of sight.

Re:Old idea with problems.. but promising..

[CmdrSam]

This is totally false. Think about Newton's Third Law.

When you throw that bag of garbage straight up, directly away from the center of the earth, it's going to exert a force on you in return directly toward the center of the earth. This won't affect Earth's rotation at all (no torque).

Besides, by your own figures, it would take 12 quintillion years of NYC's garbage before the effect was noticable. Before that we'll have to worry about the Sun going out ;)

--Sam L-L

Re:Old idea with problems.. but promising..

[LMCBoy]

What are you on about, exactly?

If we lift 60 trillion trillion tons of stuff, then a day will be longer by 9 hundredths of a second, is that your argument?

First of all, who cares? Did you know that the Earth's spin is naturally slowing down because of tidal drag from the Moon? The length of a day is increasing by about 3 milliseconds per century, and this is ridiculously larger than the effect you're worried about. Consider:

You say NYC produces 5 million tons of waste per year. Let's be generous and say that the entire Earth produces 1 billion times that (ha!), and that we decide to get rid of it by sending it all up the elevator (double ha!).

So 5 trillion tons of mass lifted per year means that the Earth's day will be .09 seconds longer because of this diabolical plan after 12 trillion years.

Did I miss something?

Re:Old idea with problems.. but promising..

[ldopa1]

"When you throw that bag of garbage straight up, directly away from the center of the earth, it's going to exert a force on you in return directly toward the center of the earth. This won't affect Earth's rotation at all (no torque)."

As long as you throw it, not lift it, which is the principle behind the space elevator. That also true as long as you don't let go (which is why a figure skater goes faster when she/he brings her arms back in). To make the space elevator concept work, you'd have to bring down an = amount of trash/rock/whatever to make the lift work economically. Nobody is going to trade trash for rock. With trash, we'd be letting go. Goodbye rotational energy.

The 12 quintillion figure is for NY's trash alone. Like I said, let's add everyone elses trash, plus payloads, etc and it adds up quickly. And again, you're talking about stopping the earth entirely, not slowing it down for the .09 seconds I was talking about.

Did you actually think that people were concerned about global warming before they started chucking billions of tons of pollutants into the atmosphere, some 50 years ago?

Re:Old idea with problems.. but promising..

[ldopa1]

Also, addendum. Yes, I did the math. I left "trillion" in there by accident. I started to say "59.8 trillion" tons, but added the zeros in the editing process, and forgot to remove "trillion".

So, actually, divide your numbers by 1,000,000,000. That's the real number of years you're trying to figure. You've done the math on your part, do it on mine, and you'll see the mistake.

That's the problem not having a peer review board when posting to /.... :) Thanks for pointing out the error.

Re:Old idea with problems.. but promising..

[mstorer3772]

Interesting, and I'll leave the others to rail against your math and the consequences you point out.

But why are you only considering 'mass going up'. What about 'mass going down'. As soon as it becomes feasable (and a beanstalk will make it happen that much sooner), you can bet people will start mining off-planet. And some of those resources will end up headed back down the gravity well.

And someone else has already mentioned that the earth acquire's a fair bit of mass naturally, in the form of space dust, meteorites and what have you.

The sky is not falling. The ground is not rising. Everything is okay. Deep breaths. There ya go... all better.

Re:Old idea with problems.. but promising..

[Anonymous Coward]

First off, sending rubbish into space is just plain *stupid*. One, it would require tremendous amounts of energy. Two, it would mean for ever forfeiting those natural resources. Remember, we are starting to mine closed landfills for valuables. Just because something sits in the ground doesn't mean that it's useless in perpetuity. However, if we launch rubbish into space, it's gone. And with all the people on this planet, we need all the natural resources we can find. I simply roll my eyes when people propose launching waste into the Sun, or out into space. Morons!

Re:Old idea with problems.. but promising..

[ldopa1]

My point exactly. Sending rubbish off is just plain stupid. As for the energy requirement, the beanstalk generates it's own energy, once it's hooked up. As far as losing the natural resources, we don't seem to have a problem doing that all of the time (practically). Most of the plastic that is buried will never see the light of day again as ANYTHING in any of our lifetimes.

Surprisingly, I for once agree with an AC.

Re:Old idea with problems.. but promising..

[n1vux]

Skip using it as a garbage disposal, I want to get to the promised orbital and L5 hotels inexpensively.

Arthur C Clarke, who first popularized the idea, was quoted on BBC/WS the other day and on websites as having predicted the Space Elevator would be a reality "Probably about 50 years after everybody quits laughing". The BBC Story online doesn't have that quote, but The Audacious Space Elevator (cache) does, and also says where he got the idea, and has more links. And if you want more information, Google it some more.

As to recent books, Kim Stanley Robinson's colors of Mars series includes destruction of the elevator's catastrophic repercussions as a key plot device. Some sort of fail-safe system is required before it could realistically be built, as the equatorial countries sharing in the falls-down-risk but not sharing in the wealth of the operators would be likely to object. (e.g., Maybe a massively fail-safed self-destruct charge in the mooring to eject it into solar orbit in case of impending collapse?)

==Sigfiles? We don't need no steenkin sigfiles.==

Re:Old idea with problems.. but promising..

[mesocyclone]

Sigh... it's the old "we are running out of space for garbage" myth again.

Just a nit in this discussion, but there is not any problem at all in terms of space for waste. I forget the figures, but basically you could put all the waste generated in the US for a century into a spot something like 10mi x 10mi. I live in the middle of a desert where the nearest large city outside of the one I live in (Phoenix) is 120 miles away! LOTS of room for rubbish. For that matter, we have huge retired open pit copper mines around here. We can use the rubbish to restore the scenery (although open pit mines are pretty cool to look at, and the Arizona town of Bisbee is built in one).

Other than that, I'm glad at least someone did the math so I didn't have to.

Re:Old idea with problems.. but promising..

[Phanatic1a]

This got modded up as interesting?

New York City's population is about 8,000,000 people. Let's assume that every person on earth generates as much waste as the average New Yorker, which is probably being overly favorable to your argument. The 6 billion people on the planet right now therefore dump out 750*13,000 tons each day, for a total annual trashload of 3,558,750,000.

5.98E24/3.56E9 = 1.68E15 years. For the notation-impaired, that's 1.68 million billion years. That's about 1.68 billion times as long as humans have even been around. It's absoulutely asinine that you'd use this even as an example.

Go ahead, if you want to. Add Yucca Mountain's 77,000 metric tons of waste and 100,000,000 gallons of radioactive waste water; you're not even up into significant figures. And the piddling effect you speak of is absolutely dwarfed by the slowing caused by the tidal influence of the moon. Even increased waste production due to increasing population can probably be ignored, since it's never going to go Malthusian and will probably reach sustainment levels sometime this century.

And hey, if it goes Malthusian, longer days are the least of anyone's worries.

Lastly, I'd suggest that nobody's going to be launching garbage into space. First of all, this just gets you up out of the gravity well, not out of orbit, so you'll still need to burn if you don't want to come back down to Earth again in the near future. Second of all, if the ecological doomsayers are right and civilization's going to starve itself because of its own environmental depradations, well, we don't want to be getting rid of our trash; it's too damned valuable to send into deep space.

Especially the stuff at Yucca Mountain.

Re:Old idea with problems.. but promising..

[Anonymous Coward]

take that 12 quintillion, and a huge overestimate of 1 billion NYC sized cities on earth, and it will 12 billion years to add up to enough to be noticable. Loss angular momentum of the earth is the least of concerns for a space elevator.

Re:Old idea with problems.. but promising..

[ldopa1]

Take a look at follow ups.

Let's hope the software controlling it is OK...

[Anonymous Coward]

"OK, everybody's in, shut the doors"
"Going up!!!" .....
"Right, we're now at floor 32760, and we should be arriving at floor 32768 in a matter of seconds..."
"Oh no! Who used a signed integer for the floor number!!! We appear to be at floor 0, and hurtling in to deep space! Somebody hit control-alt-delete!!!"

new elevator music

[fliesd]

With a trip that long they really need to re-think the music that they are playing in elevators. Kenny G all the way to the moon, I don't think so. They'll have to stop the elevator hundreds of times a day to clean up the little pieces of brain after listening to Mr. G all the way up.

Why doesn't anybody listen?

[Guppy06]

Everytime this has come up on Slashdot I've posted how foolish an idea this is (especially after 9/11), but nobody seems to listen to me.

1.) If it falls, bad things will happen. As I type this there are probably at least 10 posts to this article moderated way up that point out how "safe" this thing would be coming down. Every single one has two flaws:

• It treats the beanstalk as a series of point particles as opposed to one connected strand
• It neglects the fact that gravity is stronger towards the bottom of the beanstalk than the top

What does this mean? It means that, as the bottom comes down, the top will be yanked down faster than it would be by gravity alone. Want an analogy? Extend a tape measure to its full length. Let go and let it wind itself back up. Try not to cut your hand. And you want to build this on a large scale?

2.) People will now respond to this post saying that it won't fall down because the top will be in orbit. In order to keep the bottom of the beanstalk from whipping around the circumference of the earth every 90 minutes, you must be talking about putting the center of gravity into geostationary orbit. I've done the math. If you want to put the center of gravity of a cable with uniform density into geostationary orbit, it puts the top of your beanstalk well beyond lunar orbit (inverse square againt). And when the moon snaps off that top guess what happens.

To sum up: Not on my planet!

Re:Why doesn't anybody listen?

[Anonymous Coward]

If you want to put the center of gravity of a cable with uniform density into geostationary orbit...

Who says it will be of uniform density?

From the FAQ:

Analysis shows that the proposed ribbon (of 1cm width below 10km altitude) would break at 71.5 m/s (159 mph) or a Category 5 hurricane. The proposed location of the ribbon is not in a hurricane or high wind area.

The fact that they specify the width specifically as a function of altitude probably means that they have done the math too.

Re:Why doesn't anybody listen?

[Bullschmidt]

Technically, your second objection is trivial (well as trivial as any other part of the project) to overcome. The CM has to be in orbit. Don't continue the cable all the way out. You're right, it would be absurdly long. But instead just put on monstrous weight just outside of orbit. You have a lot less problem with radius*2 minimizing effect, and it probably simpler than building more cable

Re:Why doesn't anybody listen?

[csimicah]

The people working on this seem to think that their ribbon will burn up / disintegrate if it falls. But hey, what do they know?

Re:Why doesn't anybody listen?

[Guppy06]

"Analysis shows that the proposed ribbon (of 1cm width below 10km altitude) would break at 71.5 m/s (159 mph) or a Category 5 hurricane. The proposed location of the ribbon is not in a hurricane or high wind area."

10 kilometers isn't even a drop in the bucket when you're talking about something going up at least to 45,000 kilometers (that's 4 orders of magnitude for those of you keeping score at home).

On top of that, every little bit more you put below geostationary orbit requires a lot more mass on the far side of geostationary (to counterbalance the weight). Yet again the inverse square bites you in the ass.

And your quoted passage reminds me of another point: wind speeds at height are a great deal faster than those on the ground. Just because there is neglibible wind on the surface doesn't mean the jet stream isn't whipping by at 60+ mph a few miles over your head.

I found my numbers (as well as some other rants). If you put a huge couter-weight just on the far side of geostationary to hold the thing up, that counter-weight will need to mass about 140 times more than the mass of the beanstalk. While that may sound small, remember that even the smallest mass-per-meter gets pretty damned big when multiplied by 45 million. Not that it solves the problem of any breaks below the 45,000 km altitude...

Re:Why doesn't anybody listen?

[Guppy06]

The magic number for a counter-weight just on the far side of geostationary is about 140 times the mass of the beanstalk. 140 times the mass of something (anything) 45,000 kilometers long can't be easy to put there.

Re:Why doesn't anybody listen?

[Creepy]

Your arguement is assuming the bottom pulls the top down (collapse), but what would happen if it were cut in half or breaks further up? Does the top spin into orbit and the bottom collapse?

I really don't know much about this, and even less about how such a beast would be constructed...

Re:Why doesn't anybody listen?

[Guppy06]

"The people working on this seem to think that their ribbon will burn up / disintegrate if it falls. But hey, what do they know?"

I'd certainly like to see their numbers. Things burn up in the atmosphere because of their high relative speed to it (the space shuttle, for example, hits the atmosphere going around mach 27 IIRC). The beanstalk will start falling from a dead stop in relation to the ground. It will accellerate to terminal velocity for the lower portion and probably continue down at that constant velocity (which will be pretty fast, and when squared and multiplied by half the mass of something 45,000,000 meters long, will be a frightening amount of kinetic energy).

Besides, most of the friction with the atmosphere will be in the form of skin friction along the length of the beanstalk. Unlike skydivers, rocks and spacecraft, there's no wall of air to get compressed in front of the falling mass because (for the most part) the only thing in front of the falling mass is more beanstalk (which will be pulling down instead of pushing up as air would be). So the terminal velocity will be faster in this case than it would be for a rock.

Re:Why doesn't anybody listen?

[garyrich]

ironic, considering the subject header. From their FAQ:

"As currently proposed, the first Space Elevator is small! It is only 890 tons, less than half the mass of the Space Shuttle at launch."

140x that isn't trivial, but it's not all that massive either.

Re:Why doesn't anybody listen?

[MoneyT]

Without even having to read the FAQ I could tell you that a good portion of the ribbon would burn up on it's way down. Consider, most space debris that "falls to earth" burns up in the atmosphere. We even need to take special percautions to make sure out shuttles don't burn up on re-entry. I would think a ribbon of cable, made mostly of carbon would have no problems burning up in air. Espesialy if, as you claim, it would fall faster than it's terminal velocity.

2) I would be willing to bet the people working on this have much more scientific knowledge than you do sitting at home with your TI-83. I'm sure they've considered such things and take them into account. Do you honestly think a project like this would ever go up if we weren't 99% sure it would work?

Re:Why doesn't anybody listen?

[Guppy06]

"Your arguement is assuming the bottom pulls the top down (collapse), but what would happen if it were cut in half or breaks further up? Does the top spin into orbit and the bottom collapse?"

Orbital velocity for altitude X is inversely proportional to the altitude of X. In other words, the lower you are, the faster you have to be going in order to be in orbit.

However, for a beanstalk, every point below the top is actually going slower than the top (points toward the outside of a wheel are moving faster than points towards the inside, so a pebble stuck in the tire treads moves faster than the lug nuts). So those points aren't even going fast enough to be considered in orbit at the atltitude at the top, let alone their current altitude. Every point in the beanstalk between the bottom and geostationary orbit has a net force pulling down.

In other words, cut the ribbon anywhere between the ground and 22,000 miles up, and everything below the cut comes crashing down. Fly a plane into it at around 7 miles up, and you have seven miles of stuff coming down at you.

Re:Why doesn't anybody listen?

[Guppy06]

"As currently proposed, the first Space Elevator is small! It is only 890 tons, less than half the mass of the Space Shuttle at launch."

Are we talking 1,780,000 pounds of weight, or 890,000 kilograms of mass? If we're talking weight, then its mass will be quite a bit higher than you'd expect (force of gravity drops off with altitude). If the number they spit out is the weight, then it would be a great deal more massive than the space shuttle.

Re:Why doesn't anybody listen?

[Idarubicin]

This is a troll, right?

Everytime this has come up on Slashdot I've posted how foolish an idea this is (especially after 9/11), but nobody seems to listen to me.

Absolutely right. We shouldn't ever build any more tall buildings, or bridges, either. Yes, security is an issue, but it is for conventional rocketry as well--and we haven't stopped launching shuttles loaded with thousands of pounds of highly explosive material.

What does this mean? It means that, as the bottom comes down, the top will be yanked down faster than it would be by gravity alone.

Except that as soon as the force of the falling cable below starts to really pull hard on the cable above, the cable will snap. Repeat as necessary to get lots of little cable bits, each a wide, thin, lightweight sheet--it's no worse than being hit by a sheet of falling newsprint.

In order to keep the bottom of the beanstalk from whipping around the circumference of the earth every 90 minutes, you must be talking about putting the center of gravity into geostationary orbit. I've done the math. If you want to put the center of gravity of a cable with uniform density into geostationary orbit, it puts the top of your beanstalk well beyond lunar orbit (inverse square againt). And when the moon snaps off that top guess what happens.

Well sure, but if you read the article, you would know that the cable will not be of uniform density. In principle, the cable can be very thin near the bottm end, and thicker in the middle. Using a counterweight just beyond geostationary orbit (as proposed, again in the article FAQ) will balance the weight of the cable below geostationary orbit. Indeed, the plan proposes using cable construction equipment (which will already be at the end of the cable anyway) as part of the counterweight.

Re:Why doesn't anybody listen?

[Guppy06]

"Consider, most space debris that "falls to earth" burns up in the atmosphere."

Consider that most space debris is moving extremely fast in relation to the atmosphere, while a falling beanstalk will start falling at rest.

Consider that most space debris comes down in "chunks," allowing a wall of air to be compressed in front of it. A falling beanstalk won't have a wall of air in front of it slowing it down, it will have yet more beanstalk in front of it pullint down faster.

Consider that, since there's nothing in front of a chunk of beanstalk beyond more beanstalk, the only friction you'll have is skin friction, allowing a much higher terminal velocity than you would have with "chunks."

"We even need to take special percautions to make sure out shuttles don't burn up on re-entry."

Look at the arrangement of the heat tiles on the shuttle. The bottom and leading edges are designed to withstand much more heat than the sides or the top. With a falling beanstalk, for all intents and purposes there are no "leading edges" or a "bottom," just more beanstalk.

Think of a train. Most of the wind resistance happens in front of the engine at the front. The engine plows through the air in front of it, and the cars behind it just move into the gap that was opened.

"I would be willing to bet the people working on this have much more scientific knowledge than you do sitting at home with your TI-83."

TI-92+, actually. Bit of a life-saver when it came to doing all those integrals involved in Fourier transforms in my partial differential equations class.

"I'm sure they've considered such things and take them into account. Do you honestly think a project like this would ever go up if we weren't 99% sure it would work?"

I don't see anything going up. I only see some website talking about the idea. Not everything on the internet is true or even feasable, even on Slashdot (which occasionally posts articles about perpetual motion machines).

Re:Why doesn't anybody listen?

[hopews]

They say the ribbon will mass about 7.5kg/km (about 10lb/mile). 45,000 km of that is 315,000kg, which is less than a jumbo jet, yet its surface area is 45,000,000m x .10m or 4.5 million square meters. Thats a lot of drag. The site has more info.

Re:Why doesn't anybody listen?

[garyrich]

They don't say. I assume mass, since as you point out, weight becomes an imprecise term in this context. 125000 tons of mass would be a lot, but actually translates into nice size for a transit terminal.

It's really moot since they aren't talking about an anchored design. They just plan to extend the ribbon out as a counterweight.

Re:Why doesn't anybody listen?

[Guppy06]

"Absolutely right. We shouldn't ever build any more tall buildings, or bridges, either. Yes, security is an issue, but it is for conventional rocketry as well--and we haven't stopped launching shuttles loaded with thousands of pounds of highly explosive material."

We're not talking about something 110 storeys tall. We're talking about something 22,000 miles tall. Orders of magitude difference here, with the potential to cause damage over areas measured in "square miles" instead of "city blocks."

"Except that as soon as the force of the falling cable below starts to really pull hard on the cable above, the cable will snap."

If it's strong enough to be able to pull up tons of payload, it's more than strong enough to be able to survive a mere 9.8 m/s/s acceleration.

"Well sure, but if you read the article, you would know that the cable will not be of uniform density. In principle, the cable can be very thin near the bottm end, and thicker in the middle."

When you're talking about something 22,000 miles long, and when talking about forces being exerted in geometric proportions, minor fluctuations in thickness like "tripling" or "by an order of magintude" won't make much difference. If you want to make a difference, the thickness better flare out like a trumpet bell.

"Using a counterweight just beyond geostationary orbit (as proposed, again in the article FAQ) will balance the weight of the cable below geostationary orbit."

1.) The counterweight will have to mass as much as 140 times the mass of the beanstalk (which itself will not be a negligible mass).

2.) All points in the beanstalk below geostationary altitude have a net force on it pointing downard. If there is a cut anywhere between the ground and 22,000 miles up, everything below the cut will come down. It doesn't matter if the cut is 20,000 miles up or "merely" 7 miles up, everything below the cut comes down.

Re:Why doesn't anybody listen?

[hopews]

Erg, stupid brain. Should be 26lb/mile not 10.
7.5*2.2/.62 ~= 26 instead of 7.5*2.2*.62~= 10

Re:Why doesn't anybody listen?

[ApoxyButt]

When I was a kid, a lot of my model rockets didn't have parachutes to slow them down: they had orange nylon streamers that would flap in the wind and slow the rocket down.

I can only imagine the forces acting on a 60 km long streamer. Isn't it a decent assumption to say that the massive amount of whipping action caused by ribbon free-falling to the earth would break it up into relatively small pieces? At that point, the "newspaper floating to the ground" analogy comes into play, because the broken-off pieces aren't fastened to anything anymore.

Re:Why doesn't anybody listen?

[Anonymous Coward]

So your points are
1) It won't burn up because its moving slower than debris
2) It won't burn up because its moving faster than debris

Next point. If there is nothing but beanstalk in front, it must be falling straight down.
That being the case, what's the problem? It'll fall straight down and leave a big pile of tangled ribbon at its base.

If, on the other hand, if falls over, then it will indeed build up a wall of air against its HUGE surface area.

Finally, the tensions of falling would very likely fragment the ribbon. In fact, the article says it will be designed for this to be the case.

Re:Why doesn't anybody listen?

[Guppy06]

"yet its surface area is 45,000,000m x .10m or 45 million square meters. Thats a lot of drag."

It would be if it were falling sideways, but it won't. The side of a mile-long freight train has a whole heck of a lot of surface area, but the only thing that really matters as far as wind resistance is the surface area of the front of the engine.

Re:Why doesn't anybody listen?

[Guppy06]

"I can only imagine the forces acting on a 60 km long streamer."

The difference is that a streamer isn't under tension while a falling beanstalk would be. It couldn't flap like that because the bottom would be pulling it down and inertia would try to counteract that by "pulling up." It would probably flap quite a bit as it nears the end of the collapse, but it will be more like my tape measure analogy in its motion.

If you drop a sheet of paper edge down, it will fall down pretty fast until the bottom edge gets deflected to one side, causing the paper to curl into a U and maximizing the surface area for air resistance to play on. That couldn't happen with this ribbon because there is no bottom edge to get picked up, only more ribbon. This design will be all too aerodynamic.

Re:Why doesn't anybody listen?

[Dirtside]

So, I'm confused... when the beanstalk falls down, does it fall STRAIGHT down into a pile, or does it fall OVER? Or something else entirely?

If it falls straight down, then the entire length of the beanstalk ends up in a relatively small pile around the base structure. Very little damage to surrounding areas, I imagine, especially if the base is a floating platform in the middle of the Pacific.

If it falls over, then the entire surface area of one side of the beanstalk is pushing through the atmosphere, building up a huge wall of air, slowing its descent, so it isn't moving very fast and doesn't do a huge amount of damage should parts of it land on something.

Which is it? Or is it something else? Be specific, please.

Re:Why doesn't anybody listen?

[Guppy06]

"So your points are
1) It won't burn up because its moving slower than debris
2) It won't burn up because its moving faster than debris"

More like:

1.) It won't burn up because it starts below terminal velocity and accellerates, instead of starting above terminal velocity and having to be "braked" by the atmosphere.

2.) Its terminal velocity would be higher than for space debris because there is no air in front of the beanstalk, just more beansatlk.

"Next point. If there is nothing but beanstalk in front, it must be falling straight down.
That being the case, what's the problem? It'll fall straight down and leave a big pile of tangled ribbon at its base."

1000 tons falling straight down at obnoxious velocities (which it would be) into the ocean = tsunami.

"Why won't it just cut through the ocean like it does the air?" you're about to ask. Because sooner or later, it's going to come across something that will make it bend, be it the surface of an ocean rig that's at the bottom of the beanstalk or the bottom of the ocean, and once that initial kink comes into being at the landing point, that structure is going to whip around near the landing ponit like there's no tomrrow. Take a look at photos of trains that have jumped the rail and you'll notice that the front cars are all smashed up and can be thrown quite far from the rail because the cars behind it still have a lot of momentum and nothing else to stop it.

Sure, the structure will probably burn up in the lower atmosphere in that kind of motion at the surface of the earth, but whether it burns up or not that momentum has to go somewhere (so sayeth Newton), which will probably still spell out an atmospheric shockwave that I wouldn't want to be anywhere near.

"If, on the other hand, if falls over, then it will indeed build up a wall of air against its HUGE surface area."

If it falls sideways. Which it won't because of it's huge surface area. Nowhere to go but straight down at an obnoxious speed.

"Finally, the tensions of falling would very likely fragment the ribbon. In fact, the article says it will be designed for this to be the case."

If its strong enough to pull up multi-ton cargo, how will it break apart under its own weight?

Re:Why doesn't anybody listen?

[rholland356]

It occurs to me that to prevent a wobble from developing in the Earth's revolution (or to limit the amount of girth the Earth moves to its equator to compensate) [or, to boost the Gaia's self-esteem], you would want to mount an identical elevator directly opposite, and use each to launch identical payloads simultaneously.

Oh, it's all for naught, in any case. The Japanese will never be able to make the cable from carbon nanotubes. The reason? As soon as they let the public see it, it will become damaged from all the camera flashes...

Oy!

Re:Why doesn't anybody listen?

[Anomaly Coward]

The ribbon won't come straight down though. In fact, it will wrap around the earth from West to East (the direction of the earth's orbit). To realize why this is so, think about an object in orbit being pulled towards the earth by such a tether. At it's start it has a certain velocity tangential and proportional to its orbit. As it's being pulled in, this tangential velocity remains the same, but the radius of orbit decreases. The nearer it gets, the faster it's angular velocity gets. By the time it reaches earth, it will be going many orders of magnitude faster than the earth's surface. Assuming it has a very large surface area, it will vaporize almost immediately after hitting the atmosphere, except for a short length at the beginning that will float down at terminal velocity.

I believe you can test this easily by taking a string, a straw, and metal washer. Tie the washer to the string and pull the string through the straw. Let out a foot between the washer and the straw, and start spinning. Now pull the string in. The angular velocity increases, doesn't it?

Re:Why doesn't anybody listen?

[barawn]

Drop a piece of paper. See if it falls on its side. Drop it very very far. See how long it stays on its side then. It'll be very turbulent, and the ribbon will build up a lot of drag, and tear itself apart. This stuff is light - very light. It's no danger.

Re:Why doesn't anybody listen?

[barawn]

Did you read the FAQ? Honestly, most of the objections are dealt with in there. After that point, read the NIAC paper, there are actual numbers in there to alleviate any concerns.

The ribbon is 1 cm width from 0-10km, because that's where the atmosphere is important (winds) and it reduces wind drag. Everything higher than that is much thicker. It isn't important being thin at that point because it doesn't need to withstand impacts (the atmosphere shields it) and you don't need to worry about it burning up on reentry (as it's only 10 km).

As for the mass issue, look, this is trivial, and it's been done. Check out the FAQ, check out the proposal. It's 100,000 km long, and the top counterweight is only about 30,000 kg. Carbon nanotubes are reaaaallly light and strong. They rule.

As for the windspeed issue, at height, the air density is less as well, therefore the actual amount of force they place on the ribbon will be minimal.

Regarding your numbers, you have to remember that everyone's planning on tapering this thing: it doesn't have a constant density. Without a counterweight, a tapered ribbon would need 144,000 km to work - not the distance to the moon.They're planning on putting up a counterweight which is of order the size of the ribbon, bringing that down to 91,000 km. The density profile of the ribbon they want to use is pretty complicated: it'd take a bit of work to calculate it out, but go ahead: you'll find that they're right.

Re:Why doesn't anybody listen?

[csimicah]

So it's either going to: a) Fall straight down. Noise of ribbon hitting water traumatizes fish. b) Fall sideways. Fluttering carbon ribbon mistaken for ticker tape parade. Neither one seems like your typical "nightmare scenario" to me.

Re:Why doesn't anybody listen?

[Anonymous Coward]

> If it falls sideways. Which it won't because of it's huge surface area. Nowhere to go but straight down

Ahh, there's your error. It's been pointed out before, but maybe a new voice saying the same old thing (physics, btw) will work.

Despite what our friends the Flat-Earthers will tell you, the earth isn't stationary - it's a rotating reference frame. Accordingly, something sticking straight out 100,000km is going to have what's technically known as a metric fuckload of angular momentum.

When the beanstalk starts falling down, this metric fuckload needs to go somewhere - fuckloads don't just fuck off - and since angular momentum is proportional to the length of the beanstalk times its (orbital) velocity, less length = more velocity = beanstalk falling in the direction the earth is rotating = not falling straight down = huge amounts of aerobraking = much less velocity and enough rotational kinetic energy burned off to break the beanstalk.

Net result? The beanstalk breaks up in the atmosphere, just like the fine folks who impressed a half-million dollars out of NASA said it would.

This is, incidentally, why nobody listens to you about this - you're wrong. Common cause, really - anyone who wonders why people don't listen should consider it. :)

Re:Why doesn't anybody listen?

[Anonymous Coward]

> In other words, cut the ribbon anywhere between the ground and 22,000 miles up, and everything below the cut comes crashing down. Fly a plane into it at around 7 miles up, and you have seven miles of stuff coming down at you.

Which weighs in at a whopping 185 pounds. The technical term for the resulting effects is "yawn".

(Although the 21,993 miles of the stuff still up there might create an orbital hazard for a while before drag decays its orbit and pulls it down so it burns up.)

Re:Why doesn't anybody listen?

[Anonymous Coward]

> > "yet its surface area is 45,000,000m x .10m or 45 million square meters. Thats a lot of drag."
>
> It would be if it were falling sideways, but it won't. The side of a mile-long freight train has a whole heck of a lot of surface area, but the
> only thing that really matters as far as wind resistance is the surface area of the front of the engine.

You clearly don't know much about aerodynamics.

With long, straight objects, the parallel surface area actually has a great deal to do with the amount of drag it experiences - an arrow, for example, gets most of its drag from the shaft (http://www.student.utwente.nl/~sagi/artikel/bas/b as1.html). It's a fluid dynamics thing.

The beanstalk will generate lots of drag _regardless_ of how it falls.

Re:Why doesn't anybody listen?

[Anonymous Coward]

See if you have a friend that has at least a 3rd floor apartment and a balcony. Get a roll of toilet paper. Go to said friend's pad. Unfurl the toilet paper until it touches the ground. Tear loose from roll, and release. Witness the carnage.

Re:Why doesn't anybody listen?

[nanoakron]

Very true, if you only use a cable of uniform density. But the minute you stick a multi-ton counterweight at the orbital end of the ribbon, the centre of gravity shifts greatly, right about to 38,500km (like they put in the FAQ).

So, what happens when it breaks? Depends where it breaks of course...Tried cutting a piece of string when you're spinning it around your head with a rock tied to the end? Cut it short and it goes flying, stuck to the rock...cut it long and the string wraps around your head.

-Nano.

Re:Why doesn't anybody listen?

[infernow]

Popular Mechanics has an article regarding an orbital elevator here.
The problem regarding the center of gravity is solved by using an asteroid as a sort of space anchor. I guess NASA figures that if they can build the rest of the elevator, wrangling up a suitable asteroid for a counterweight would be easy.

Re:Why doesn't anybody listen?

[stevelinton]

To take the second point. The Centre of Mass has to be in geostationary orbit. As several people have said, the cable is very non-uniform. It is thicker close to orbit, thinner near the ground and has a
large mass attached somewhere outside geostationary orbit.

So, what happens if it is cut? Cut it at the bottom and almost nothing happens. The tension at the bottom is only enough for stability and load-carrying. So, cut it and the bottom end just flaps around until you catch it again.

Cut it below about 10000 km altitude and everything below the cut falls to the ground. The cable will almost certainly snap, in multiple places, or could be deliberately cut using explosives or something like thermite (the fal takes hours, there is plenty of time for cable control to press the big red button).
The bits from lower altitudes fall at their terminal velocity in air (probably not all that fast) close to the bottom attachment point, the bits from higher up probably burn in the upper atmosphere, or at least get slowed to terminal velocity.

Cut it further up, and if cable control can move fast enough, they cut it at about 10000km and the bits above that altitude remain in orbit (an elliptical orbit that just misses the atmosphere).
Also, the further up the cut is, the longer it all takes to happen.

Steve

Angular momentum

[zik0]

So the elevator pulls itself straight up. Doesn't it need to pull forward as well to increase its angular momentum?

Re:Angular momentum

[Anonymous Coward]

I would guess that the orbiting space station
would need to thrust forward as the car rose-- pulling the elevator car to the space station's orbital velocity.

Re:Angular momentum

[breadbot]

I think you could compensate at the base station.

For all of these questions, it seems to help to think of swinging something around yourself on the end of a string. You can certainly accelerate it without touching the far end -- it just won't always go out in a straight line.

But really, although I haven't finished reading the 80-page description by Edwards, I'll bet an answer is in there.

Charley and the Chocolate factory...

[TibbonZero]

Geez, someone read the sequel the this horridly funny book. It has a 'space elevator' in it. I always thought it was absurd, but I guess someone wanted to make it a reality. But I just want to know when they will invent an Oompaloompa, or a real 'Everlasting Goobstoper'...

Design Problem? Here's the design problem:

[Pollux]

I don't understand these people who think you can build an elevator into space. Can't anybody understand that you cannot just "tie" a cable from Earth to something in orbit in space? For building an elevator into space, there are two problems that need to be accomplished:

1) Find a substance to build a cable that can support it's own weight (plus the weight of whatever it will "carry") in space. For a long time, this was impossible, until Carbon nanotubes came along. But even with this problem fixed, no one has even considered the second problem.

2) Any object in an orbital pattern with a celestial body (Earth) is subject to two forces: inertia and gravity. We know this as freefall. Astronauts in space are constantly falling (gravity), but never actually fall to earth because inertia keeps pushing them forward. If one of these forces is knocked out of balance, aka the orbital body slows down its forward velocity, it will fall to the Earth. So, what happens when we tie a cable to, say, the space station from the ground below?

IT WILL FALL TO THE EARTH!

The space station orbits the Earth once every what...couple hours? I don't know, but I do know that it's orbit is much faster than the time it takes for the Earth to spin once on its axis. If we attach an elevator cable from the ground to the space station, it will literally whip the station down upon the Earth, because the station moves much faster than the Earth. Since the forward motion is hampered by the cable, down it will come.

The only possibility of maintaining an actual elevator cable is if it is hooked onto something in geosyncronous orbit with the Earth. The only problem there is that the object would have to be 40,000 miles away from the Earth to maintain constant orbit with a fixed position on Earth. Good luck.

What makes me even more skeptical about this report is a statement they make on their webpage:

In its initial report, the company has found that a space elevator capable of lifting 5-ton payloads every day to Earth orbit, the Moon, Mars or Venus could be operational in 15 years.

Mars? Venus? How in the universe are we able to tether a cable onto another planet?!? There isn't even a fixed distance in that senario!

Space elevator CONFERENCE in Seattle today!

[MattJ]

Highlift Systems is sponsoring a two-day conference (Space Elevator Conference 2002) at the Seattle Sheraton, ending today. See http://www.confcon.com/sp_elev_02/sp_elev_02.html . I Googled to get the location details, here.

And yes, ny the way, they had a dinner last night at the Space Needle :-)

You're wrong, do the math.

[mikeee]

59,800,000,000,000 trillion tons into space to affect the aforementioned change. Again, a tremendous amount, right?

Well, yes, actually.

Consider this: New York city alone produces 13,000 tons of residential waste a DAY, and they've run out of places to put it (Again, Source [fathom.com])... It adds up REALLY quickly.

You're using your intuition, and it's wrong, wrong, wrong.

It doesn't add up. Assume everyone in the world produces as much trash as a New Yorker City resident, and that we double that for non-residental, and that we send all of the trash in the world into space.

That's 13K*(1/.002)*2= 13 million tons of trash a day. To achieve the slowdown you mention (.1 second/day) would take about 1.2*10^16 years. Tidal effects are slowing the earth much faster than that. More to the point, the sun will have blown up by then, making the rotation of the earth moot. Hell, I'm not sure all our protons won't have decayed by then - anybody know the numbers on that one?

Re:You're wrong, do the math.

[ldopa1]

Are you saying that there are only 1000 cities on the earth producting 26,000 tons of waste a day in total? Let's add commercial waste. Let's add waste water. etc etc etc. Ad infinitum.

Also, addendum. Yes, I did the math. I left "trillion" in there by accident. I started to say "59.8 trillion" tons, but added the zeros in the editing process, and forgot to remove "trillion".

So, actually, divide your numbers by 1,000,000,000. That's the real number of years you're trying to figure. You've done the math on your part, do it on mine, and you'll see the mistake.

That's the problem not having a peer review board when posting to /.... :)

Re:You're wrong, do the math.

[mikeee]

Are you saying that there are only 1000 cities on the earth

No, that NYC is about 1/5000th of the world population. (10 million / 5 billion?). I already added commercial waste; sending waste water off planet is just silly, for the same power you can boil off the water...

Ok, so it's still over a million years before the effect is even measurable. I believe this is still less than tidal effects, and you're assuming we won't be doing much recycling 100k years from now.

Also note that you have to subtract any raw materials (asteroid mining, anyone?) brought down by beanstalk. If it really becomes a problem, you can just haul random crap down for the angular momentum.

Re:You're wrong, do the math.

[ldopa1]

"sending waste water off planet is just silly, for the same power you can boil off the water..."

Unless it's radioactive. Then you have radioactive steam.

I don't think that it's a real problem (to be honest, in the time frames we're talking about, humans will be worm food, IMO). I just don't want to see people using it as a tool for putting our problems "out of sight - out of mind".

Shipping the WTC wreckage out to space alone would add 1.2 million tons to the total. We ought to be able to do SOMETHING with trash other than ship it away to someplace that isn't personally offensive.

one counterpoint

[FirstNoel]

WHat about all the debris that falls back down to Earth everyday?

I don't really know, but if I rmember correctly it's quite a lot.

Space dust, meteorites, old satellites...

Minus the old satelites, aren't we actually gaining mass everyday?

Of course though you reference about when people start shipping out the trash everyday...

That could be the real start of problem.

Sean D.

Nanotube technology can't handle this!

[umrgregg]

Nanotube technology still has a ways to go before it can handle the space elevator problem. Certainly NASA wouldn't be funding the project if there was no hope of it getting off the ground...

A reply to Arthur C. Clarke's letter to Scientific American:

Avouris and Collins reply: We have not read Edwards's report on the subject, but one may anticipate great difficulties in the implementation of the project. Although it is true that individual nanotubes have very high tensile strength, the record length achieved for a single nanotube is a mere two millimeters, and this applies only to multiwalled nanotubes, which have lower strength than single-walled tubes. One could make ropes from shorter tubes, but tube-tube adhesion is not particularly strong. That said, the carbon nanotube field is advancing at an incredible rate, and difficulties that appear insurmountable today may find simple solutions tomorrow.

Irregardless of the hurdles facing scientist trying to overcome the current limitations to nanotube technologies, I hope that this project finds itself successfully completed!

Re:Design Problem? Here's the design problem:

[Rasta Prefect]

The only possibility of maintaining an actual elevator cable is if it is hooked onto something in geosyncronous orbit with the Earth. The only problem there is that the object would have to be 40,000 miles away from the Earth to maintain constant orbit with a fixed position on Earth. Good luck.

Actually, the idea is to tie the cable to something a little _past_ geosyn, and speed it up so that tension is maintained on the cable, making up for the section of cable that isn't moving at the correct orbital velocity for its height.

Re:Design Problem? Here's the design problem:

[aallan]

I don't understand these people who think you can build an elevator into space. Can't anybody understand that you cannot just "tie" a cable from Earth to something in orbit in space?

I really hope you're deliberately trolling, but just in case...

The only possibility of maintaining an actual elevator cable is if it is hooked onto something in geosyncronous orbit with the Earth. The only problem there is that the object would have to be 40,000 miles away from the Earth to maintain constant orbit with a fixed position on Earth. Good luck.

Err, yes? Thats exactly what people are proposing, in fact people have been proposing this for many years. See this NASA Summary for details for the current ideas. You'll notice that they specifically say that the elevator will be to geo-stationary Earth orbit (GEO) in the first sentence.

Al.

Re:Design Problem? Here's the design problem:

[spitzak]

The cable is tied to something *higher* than geosynchronous orbit, and travelling faster than something at that orbit level would. It works like swinging a rock tied to a string around your head. The string is kept straight.

Anything let go from this far end would be travelling faster than orbital speed. Apparently it is fast enough that it is escape velocity from Earth and thus the cable can be used to "throw" things to other planets.

NASA Info

[wyldeling]

NASA's been talking about this for over a year now, here and later here. The second article includes a reference to the NASA report about the space elevator. Additionally, it, also, includes details on other propulsion technologies that can come out of this study.

Re:Design Problem? Here's the design problem:

[.com b4 .storm]

Mars? Venus? How in the universe are we able to tether a cable onto another planet?!? There isn't even a fixed distance in that senario!

Aside from this bit, I thought your comment was reasonably rational. But then you make a statement like this, and it makes me wonder if the purpose of your whole post was not so much to be informative, but to be sensationalist.

If you took three seconds to think about it, you would come to the conclusion that they probably mean they would lift things away from the Earth, to a point where they could be transported by other means to the Moon, Mars, Venus, or wherever. Granted, they could have worded that a lot better...

No basis for Cost / Investment estimate of $10B

[patiwat]

Although Highlift devotes considerable technical detail into estimating the operating cost of the space elevator, nowhere do I find any detai of how he gets his $7-10 billion cost of initial investment. This of course, is the whole problem. It doesn't matter if the elevator works on solar power and requires no infrastructure or maintenance - the key barrier to its construction will be the magnitude of investment. This penny-wise and dollar-foolish approach of engineering is very frustrating for someone like me who really wants to see a working space elevator in my lifetime.

To put things into perspective, Europe's Ariane 5 launch vehicle cost nearly $10B in development over a decade. If his $10B estimate is correct, then the Highlift space elevator isn't a project that any single country (besides the US) can undertake. Another perspective: Boeing's Sea Launch projeect, which involved a platform in the equatorial Pacific, a fueling and operations ship, and considerable infrastructure, cost less than $1B (considerably cheaper than Ariane 5 because it didn't involve a new launch vehicle).

I want to see the elevator happen, I really do. But to see it happen, these guys have got to get out of their "this is really cool on paper" engineering mode and get into a hard nosed "how are we going to make money out of this and make this really happen" mode.

Re:Great news, but

[EvilBudMan]

What about the wind load? Oscillation? Also, wouldn't this thing act as a giant lightning rod? That cable would have to be very very strong for it's weight.

Orbital speed?

[Anonymous Coward]

The Earh's circumference is 25,000 miles, meaning the orbital speed at the equator is just over 1,000 miles per hour. Since a geosync orbit is at about 6 times the earth radius, anything there orbits at over 6,000 mph (closer to 7,000). How will the tether supply the HORIZONTAL component of velocity?

i can't believe no one's mentioned...

[Anonymous Coward]

the tower of babel.

potential use?

[brad3378]

Sure would make for an awesome cell phone tower!

Re:Great news, but

[Anonymous Coward]

Not one of your best, PG. I'd stick with the technobabble, you're getting a little too obvious there. When your falsehoods are blatantly obvious to anyone with 3rd grade geography knowledge...

Of course, there are still plenty of idiots who were dumb enough to bite, but that's no real challenge.

Re:It _can_ fall

[f97tosc]

If the cable breaks anywhere (except at or near the outer end) the piece closer to earth will invariably fall down. I could see quite a few scenarios (collisions, space debris, undetected cracks, etc) making it break. Making contingency plans for a broken cable should be the least of the constructors concerns, however. Making and lifting this cable is far beyond any engineering task ever attempted (having studied physics at Caltech I am highly sceptic of the project, and especially the timeframe). If they really could build the cable, then putting in, say, explosives or rockets to make it fall the right way should not be too difficult. Tor

Many poorly dodged questions there.

[Valdrax]

Several times they dodge the questions of weather by saying that they'll simply put it in a place where there are no hurricanes and no thunderstorms. While I don't doubt there are places where these are infrequent, I don't believe for a second that there is anywhere on Earth around the equator where it's impossible to run into bad weather.

If I remember correctly, the reason they don't want to deal with the lightning question is because running a huge electrical charge through a carbon nanotube will make it explode into a cloud of graphite, severing the connection.

So, the question becomes, what do they plan on doing when (not if) bad weather comes for the orbital elevator. Can it be moved?

Another unanswered question is what they plan to do about space debris.

Re:Many poorly dodged questions there.

[Tablizer]

(* Several times they dodge the questions of weather by saying that they'll simply put it in a place where there are no hurricanes and no thunderstorms. While I don't doubt there are places where these are infrequent, I don't believe for a second that there is anywhere on Earth around the equator where it's impossible to run into bad weather.....lightning....through a carbon nanotube will make it explode into a cloud of graphite *)

It seems pretty clear that they have to assume that there will be such problems on occasion, and hopefully reduce the risk just to the loss of the cable and cargo.

Hmmm. How about little parachutes every X feet?

sweet

[brad3378]

I can see the Base Jumpers getting ready to conquer this one!

Re:CLAIMED

[Anonymous Coward]

Railroad Tycoon was better.

Wow, I just took such a huge after-lunch dump, that I am considering putting in an application to be the new goatse guy.

The Space Elevator

[keithatcpt]

Oh Good. Now my Drop Singularity Tank MK2 can make drops anywhere on the planet!!

Re:Good idea for nuclear waste? QWZX

[Anonymous Coward]

Good God, you've proven everything I've ever thought about the intelligence of environmentalists.

Pollute the sun?? Sheesh, man, drop the greenpeace pamphlet and pick up a science book.

Bullshit

[Anonymous Coward]

yeah, read the resume of the second in commmand:
Michael J. Laine
Experience
1995 - Present Laine Property Management Bremerton, WA
Owner
Purchased a $550,000 value property for $8.00 cash. The value has since
increased to approximately $1,300,000.

Ok, the $550,000 value property was PURCHASED for $8.00. So it's value is ... $8.00. Now it is up to $1,300,000. Bullshit, I'll give him $20 for it.

How do they lift the thing up?

[ncoder]

I didn't see this question answered...

It's a heavy cable.

HA HA

[timeOday]

Of the technology required to construct the US$10-billion elevator, the only piece that does not exist is the material that would constitute the ribbon

That cracks me up.

I know!

[Lowca]

Actually, that's probably a very good idea for a elevator with a shitload of floors. While a person's on the elevator, let him press only one floor button. Use fingerprint/retinal/DNA/whatever scans.

(Yes, I know the parent poster was joking. No, that does not mean some jackass wouldn't do it.) ;-)

read the FAQ

[Preposterous Coward]

It talks about wind load, oscillation, and lightning...

crane

[madhippy]

this is probably very very wrong, but how about an orbital crane that lifts cargo ...

= 2x 747

[Preposterous Coward]

meaning the total mass of this thing that reaches to geosynchronous orbit is not much greater than two 747s waiting for takeoff on parallel runways at your favorite airport. (I don't remember the exact number, but the max takeoff weight for a 747-400 is around 850,000 pounds.) That frankly strikes me as a stunningly *small* amount of mass...

For that matter, it's probably vastly less massive than a transpacific communication cable, which is somewhat shorter but must have much more shielding, etc.

And You Thought Airport Shuttles Were Expensive

[Uggy]

So just how much would the airport shuttle to the middle of the Pacific be? Hmmm?

Another hard SF reference

[rawdot]

Robert L. Forward also wrote about elevators (up and down, slinkying across the lunar surface) in Timemaster.

no point

[whistlestopJunkie]

you still have to get the cargo up there, which takes energy. maybe a little less if you don't have to make continuous attitude adjustments, but i'm thinking it would be a comparable expense in energy... scramjets. half the fuel is the oxygen in the atmosphere, which could be replenished by replanting all the deforested rainforest and replanting a lot of defunct temperate forests. plus maybe have genetically engineered hyperactive algae farms putting out high yield of oxygen and sucking all that co2 in... like as if they were on speed. hmmm.

Great Glass Elevator

[DaytonCIM]

I think someone should tell Willie Wonka and Charlie that their elevator isn't that great anymore.

what about...

[hakkikt]

setting up the elevator near the poles...

shouldn't this avoid or, at least, diminish the angular velocity of the external end of the elevator?

Re:what about...

[breadbot]

... Except that that angular velocity (and its corresponding centripetal acceleration) are what keeps the thing up ...

However, Earth's poles have changed before...

[emil]

...and as far as I know, we don't know why. Perhaps it might be useful to find out before deployment?

Nah.

Just so long...

[MoneyT]

as Genom doesn't get a hold of this, we should be all set.

[If you don't watch any anime, you won't get it. For those of you that do, go find Bubblegum Crisis]

It just doesn't make sense

[Control-Z]

Oh sure it makes sense that it would be cheaper to take an elevator into space than a rocket.

But the whole idea of a space elevator just seems ridiculous. Lightning, high winds, gravity, terrorists, meteorites, the strength of the materials. Unless there's a significant breakthrough in materials, I don't see it happening in 50 years let alone 15.

$10 billion is *nothing*!

[GPS Pilot]

This first space elevator could be built for between $7-$10 billion

People, put things in perspective. Since design work began in the early '70s, the U.S. has spent about $180 billion on the Space Shuttle program. What do we have to show for it? Certainly not reliable, low-cost access to space. The space elevator will change everything. Especially considering the fact that you can use it to lift materials for additional space elevators -- making the construction cost for subsequent space elevators lower than for the first one.

$10 billion for our first space elevator would be the bargain of the millenium.

Laser damage

[charlie763]

Would the laser used to power the cart damage the ribon if not aimed properly? If the damage does not occur at once it may have an effect over time.

[M.C.] Hammer is a tool...he he he...
-Mark Twain

I can see it now...

[Hoi Polloi]

The thing will stop at EVERY floor and have bad music piped in.

Two words: "bungie jump" :-)

[GlenRaphael]

This project would be a godsend for the extreme sports crowd!

Cue "girl from ipanema" on vibes through a tinny musak speaker and imagine a bored nasal-voiced elevator operator:

"First floor: first-time jumpers please exit here..."
"Second floor: hanggliders, extreme bungie jumpers, observation deck..."
"Third floor: parachutists..."
"Fourth floor: extreme parachutists. Watch that first step; it's a lulu!"
"Fifth floor: atmospheric scientists. Please hold onto the railing and remember: water ballons are strictly prohibited..."
"Sixth floor: astronauts, colonists, satellite personnel. Everybody out!"

traditional solution

[shren]

the traditional solution is for buisnesses that make use of the space elevator to relocate to it's vicinity. Does that mean undersea cities? Industrialized pacific islands? What if the center of the economy shifted out into the middle of the ocean? Bizarre to think about.

Pole-y Cow!

[virg_mattes]

> However, Earth's poles have changed before and as far as I know, we don't know why.

I can't tell if you're goofing me or not. I hope you're aware that when scientists refer to the Earth's poles changing, they mean the north-south orientation changes (that is, compasses start pointing south, then go back to pointing north) and not that the actual Earth did flip-flops.

What an image that would be.

Virg

Re:Pole-y Cow!

[Scott Carnahan]

I hope you're aware that when scientists refer to the Earth's poles changing, they mean the north-south orientation changes (that is, compasses start pointing south, then go back to pointing north) and not that the actual Earth did flip-flops.

This is not necessarily true. Since the Earth is not a rigid body, it is possible for the mass distribution to shift over geological time periods. Substantial evidence for historical changes in the Earth's axis of rotation has been accumulated, although as a non-geologist, I cannot say whether it is widely accepted. You may want to search for True Polar Wander for more detailed information. This phenomenon is quite different from the magnetic field shifts to which you seem to be referring.

Nanotubes

[ehiris]

Pretty easy to maintain as long as nobody takes pictures of them.

Re:Why doesn't anybody listen? - to the FAQ?

[mrbuttboy]

Why does it scare you so much that something tall may fall?? Yes it is going to be 22,000 miles long. But it is going to be VERY thin,very little over all mass. There is going to be a VERY small amout of mass in this compared to the world trade towers. Should they not have been built?

And,even if the cable falling was much worse then they say, WHO CARES? There are going to set it in the middle of the ocean. If, despite what the FAQ says and you are correct, it doesn't self-destruct on the way down WHAT exctaly is it going to hit? The ocean? The platform it is connected to?

It's always so sad when people don't know how to read.

Thoughts About This

[virg_mattes]

> At the geosynchronous orbit you can move to any other point on that orbit in a simple way. An easy push will do. Just be careful not to hit any satellites.

I'll assume you meant geostationary, and you're right, but egad, that'd have to be a very long ribbon indeed to reach that altitude (more than 11,000 miles, since geostation for free flyers is 22,000+ miles and even with the cable itself counted in for mass you can't get shorter than that realistically). More likely is that the end of the ribbon would be far below that, with a counterweight at the top end to keep it vertical, which would still allow for switching ribbons (remember that I said two-way trips were only a problem with one ribbon up).

> Also, that spot at the cable in the geoshnchronous orbit would be a perfect for a space station, which would easily grow because it is cheap to send new modules up.

It's not really necessary to put a space station in geosynch orbit. First, since it's easy to bring stuff to it with the elevator, it's better to bring up fuel for station keeping instead (remember that geosynch for free flying no-power maintenance is 22,000 miles), and second, the cable's not going that high anyway.

> I guess you could even suspend an electricity cable on the ribbon.

Nah. Solar panels. I do like the idea of hotels up there, though. I'd be in line, for certain.

Virg

Bringing mass down...

[Anonymous Coward]

I don't see bringing mass down as a huge issue. After all, thousands of tons of space debris hits the earth every day. Add to that the asteroid mining, etc, we'd get up to once we were out of the gravity well, I don't think we'd have a big problem with this. Besides - what is the big deal if we do lose a couple of seconds a year? We're already adjusting the clock on a fairly regular basis due to this exact problem, but in reverse... :-)

Sci-Fi Novel Potential

[gottabeme]

I read the replies to this, and it sounds like it's not a problem after all, but I still see potential for a sci-fi novel here. Imagine years in the future, the Earth's waste is being sent into space, and is causing the Earth's rotation to slow, causing problems at home. Several nations get together to make the trash-exporters stop. Hmm...that has the potential for a series of novels. You could have spy parts, military parts, average-citizen parts...

Cooling

[Michael Woodhams]

They're going to have a hell of a cooling problem: all the inefficiencies in the conversion of laser to electricity and in the drive train will turn to heat.

Space: Mother Nature's garbage can

[Anonymous Coward]

Just fling all that nasty nookular waste way the heck outta here!

Re:Why doesn't anybody listen? - to the FAQ?

[Guppy06]

"Yes it is going to be 22,000 miles long. But it is going to be VERY thin,very little over all mass. There is going to be a VERY small amout of mass in this compared to the world trade towers."

Why am I scared? Being one long strand, the top will accelerate as fast as the bottom. If we didn't have an atomsphere, that acceleration would go unchecked. 9.8 m/s/s over 45,000,000,000 meters gives you a velocity that's an appreciable fraction of the speed of light, a velocty about where a single gram would have about a kiloton of TNT in kinetic energy.

Yes, the atmosphere will slow it down, but not nearly as much as people here on ./ seem to think it will (with nothing more than skin friction I don't see any reason not to believe that it would be coming down quite a bit faster than the speed of sound). And instead of grams falling down we'd have tons.

Re:Why doesn't anybody listen? - to the FAQ?

[Anonymous Coward]

> Why am I scared? Being one long strand, the top will accelerate as fast as the bottom.
> If we didn't have an atomsphere, that acceleration would go unchecked. 9.8 m/s/s over
> 45,000,000,000 meters gives you a velocity that's an appreciable fraction of the speed of
> light, a velocty about where a single gram would have about a kiloton of TNT in kinetic energy.

Yes, but if we didn't have an atmosphere, we'd all suffocate before it finished falling anyway.

If you're willing to make sufficiently nonsensical assumptions, you can come up with any absurd conclusions you like.

In the real world, atmospheric friction decelerates and destroys large meteors every day, and those meteors have high speeds (60-70 km/s - http://liftoff.msfc.nasa.gov/Academy/SPACE/SolarSy stem/Meteors/meteors.html), occasionally comparable (or higher) mass, and _much_ less surface area for atmospheric drag.

Even if something _does_ hit the earth, your estimates for kinetic energy are laughable - an asteroid with the same 750-ton mass _already_ travelling at high velocity (30 km/s) has only half the energy of the Hiroshima bomb (~10kT). There are _already_ several of those each year (http://www.astro.virginia.edu/class/oconnell/astr 121/guide22-s02.html), so one more wouldn't make a difference.

Do some research - the kinetic energy from something like this is *not* a problem. Where there might be room for concern is micro-sized nanotubes being distributed in the atmosphere and causing breathing disorders (as some allege occurs with damaged stealth aircraft). The FAQ recognizes that this is unknown, a possible problem, and something they're studying and design around.

THIS IS COOL!!!

[sysbot]

hmmm.....how are they planning on counterbalance this thing.

Someone PLEASE explain this. Show me the math.

[Max Threshold]

If a mass is hoisted into orbit on a cable, doesn't it still need to be accelerated horizontally?

Likewise, if the mass is hoisted by wheels running against the cable, won't the cable will be pulled down just as much as the mass is pulled up? How much mass can they hoist before the cable falls?

And finally... ba da bum...

Everyone knows that if you are spinning and you extend mass away from yourself, your rate of spin slows. If the above two assumptions are false, then doesn't this one have to apply? How much mass can they hoist before the earth's rotation is measurably slowed? (I know, the earth is frickin' huge... I'm talking really tiny measurable changes here.)

Re:It _can_ fall

[some guy I know]

Making and lifting this cable is far beyond any engineering task ever attempted

Well, I don't know about making the cable, but the builders don't have to lift it; instead, they build it in geosynchronous orbit and drop it to the earth (while simultaneously "dropping" the counterweight outward).
Where do they get the material?
Asteroid(s) redirected into earth orbit.

Arthur C. Clarke described all of this brilliantly in his novel, "The Fountains of Paradise".

Space Elevator

[wackhamptonio]

If you think there is any chance of this going up within 15 years, you probably believed Drexler's predictions of nano-everything ten years ago. That said I hope it works...

GoDaddy croaked, try here

[leonbrooks]

HighLift Systems' real provider lives at http://highlift.1000planets.com/.

Working URL at 1000planets.com

[joee]

Since www.highliftsystems.com seems not to be working now, you may wish to try http://highlift.1000planets.com/ .

Laser powered?

[Sindri]

THE LASER: The climber is powered using a laser that beams at photo cells on the climber's underside. The power is converted to electricity, which is used by conventional electric motors and set of rollers to pull the climber up the ribbon at speeds up to 200 km/hr.

What happened to fossil fuel piston/turbine engines?

Re:Laser powered?

[breadbot]

Lack of oxygen for 23,995 of the 24,000 miles to geosynchronous orbit -- and carrying oxygen would limit the payload of the lifters.

Re:Laser powered?

[Sindri]

Bzzzt! Wrong answer! Rockets carry oxygen to reach geosynchronous orbit all the time, and a lot more than needed to climb the wire. The weight of the oxygen needed is probably very similar to the weight of the fuel.

Misunderstanding

[virg_mattes]

> Substantial evidence for historical changes in the Earth's axis of rotation has been accumulated, although as a non-geologist, I cannot say whether it is widely accepted.

Oh, okay, now I get where you're going. If you're referring to the Earth's axis wandering, that's not really an issue with a space elevator. Although you're right that the Earth's axis changing will change where geostationary stuff needs to be to stay geostationary, there are two things that work in favor of the elevator. First, polar wander happens slowly enough not to put huge stresses on the ribbon. Second, the ribbon isn't a free flyer, it's anchored at one end and counterweighted at the other. The counterweight will arguably have navigation engines, and these can handle the minor corrections in course to keep the ribbon functionally geostationary as the planet wobbles away under it.

Virg

D'oh!

[virg_mattes]

> maybe im not up on the 'new units', but isnt current in amperes?

Um, when I said, "It will carry a current, but it's in the range of milliwatts..." I, um, meant, uh, "it'll currently carry power in the milliwatt range..." Yeah, that's it.

Virg

Re:Great news, but

[Anonymous Coward]

Fortunately for him, there are very few USians with 3rd grade geography knowledge.

Re:Why doesn't anybody listen? - to the FAQ?

[smoondog]

I think you've just shown some pretty good evidence that the cable will break on the way down.

-Sean