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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.
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.
If you build it, they will come...
Strange women lying in ponds distributing swords is no basis for a system of government.
I sure hope it can get you down as well.
According to this BBC article covering the same story, a fifty year timeline is more likely.
Toronto-area transit rider? Rate your ride.
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?
Lawrence Lessig is my personal hero.
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.
Mouse powered Chips, Open source Processors and Lego
i think it would only just "stay there" if you snipped it twice, at the same moment, at equidistant spots from the center.
slashdot: where everyone yells sarcastic metaphors to themselves to understand the issue
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.
>>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"
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.
Mouse powered Chips, Open source Processors and Lego
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
"I have never let my schooling interfere with my education." - Mark Twain
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.
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?
_ _ _ Go for the eyes Boo! GO FOR THE EYES!
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.
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.
~ kjrose
Houston, I think we have a problem.
"Scotty one to beam up."
"I'm doing the best I can captain but the elevator is stuck on floor 3."
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.
~ now you know
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.
Beware of Programmers who carry screwdrivers. -- Leonard Brandwein
...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?
There are 01 types of people in this world. Those that understand binary, and me.
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
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.)
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?
Go read some bible: nubible.com
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.
> Check an atlas.
Check the article. The phrases "floating platform" and "equatorial Pacific Ocean" are prominently featured.
Virg
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
$570,000???
Isn't that a wee-bit expensive for a dog-eared copy of Fountains of Paradises ????
The elevator can be funded privately, publicly, or with a combination of the two.
In other words "We don't know".
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.
> 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
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.
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.
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.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
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.
The Uncoveror: It's the real news.
First of all, you have the technical issues. There are no NEO objects strong enough to support hanging an elevator from.
e /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).
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.Shuttl
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?)
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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)
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?
This is the NFL, which stands for "Not For Long" if you keep making those bulls*** calls.
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!
That what was all this school was for... to teach us how to solve our own problems. -- janeowit
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.
Life is like a web application. Sometime you need cookies just to get by.
"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!
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
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
I have no problem with your religion until you decide it's reason to deprive others of the truth.
"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?
My $0.02 will always be worth more than your â0.02, so
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.
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.
Maybe the state's highest function is to grind out insoluble problems. (Zelazny, Hall of Mirrors)
The space elevator has been featured in a lot of books, most recently David Gerrold's "Jumping off the Planet".
.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.
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
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.
The Dopester
"Yes, I'm a Karma Whore, but I'm doing it to pay my way through school."
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.
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!
However, only the single-walled variety of nanotubes catch fire. Those with multiple walls do not explode - the researchers are unsure why.
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'...
Tibbon
tibbon.com
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...
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
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?
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.
Why?
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.The Daily ACK - Eclectic posts by yet another hacker
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.
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.
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...
Space elevator slowing down the earth's rotation?
Hey! I always wanted to fit more time into a day, now here's my chance.
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.
I don't care if it's 90,000 hectares. That lake was not my doing.
Sure would make for an awesome cell phone tower!
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.
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
I can see the Base Jumpers getting ready to conquer this one!
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).
It talks about wind load, oscillation, and lightning...
"Biped! Good cranial development. Evidently considerable human ancestry."
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.
"Biped! Good cranial development. Evidently considerable human ancestry."
So just how much would the airport shuttle to the middle of the Pacific be? Hmmm?
Toddlers are the stormtroopers of the Lord of Entropy.
...and as far as I know, we don't know why. Perhaps it might be useful to find out before deployment?
Nah.
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]
T Money
World Domination with a plastic spoon since 1984
If you notice anything else in the project that doesn't quite make sense, rest assured that a wizard will take care of it.
The thing will stop at EVERY floor and have bad music piped in.
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
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!"
I play Nerd-Folk!
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.
Maybe the state's highest function is to grind out insoluble problems. (Zelazny, Hall of Mirrors)
> 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
Pretty easy to maintain as long as nobody takes pictures of them.
> 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
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.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
So what happens to the smaller ribbon? I don't think it gets combined with the other one, does it?
I don't think anybody reading slashdot, myself included, will ever join the thousand mile high club.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
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.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
"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."
./ 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.
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
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.
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.
Dyolf Knip
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!
Dyolf Knip
HighLift Systems' real provider lives at http://highlift.1000planets.com/.
Got time? Spend some of it coding or testing
> 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
> 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
I think you've just shown some pretty good evidence that the cable will break on the way down.
-Sean