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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.
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.
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.
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.
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.
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.
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
> 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.
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.
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.
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.
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.) 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!
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.
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?
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
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").
HighLift Systems' real provider lives at http://highlift.1000planets.com/.
Got time? Spend some of it coding or testing