Space Elevator.....
- Thread starter All Seeing Eye
- Start date
I've heard so much good about those novels but never been able to catch them!
If severed below ~25,000 km the top would float away upwards and the bottom would fall to the east of the anchor -let's all hope the guys that build this (because someday someone will) make sure they don't build it to the west of any big cities.
^^Well, Robinson's catastrophic version of events might be a little inaccurate. Or at least it would be a different situation on Mars than on Earth, where we have a denser atmosphere.
http://en.wikipedia.org/wiki/Space_elevator#In_the_event_of_failure
So an attack on a space elevator could cause some pretty serious disruption of travel, and could be dangerous or fatal to people on the elevator itself or the geosynchronous station, but it wouldn't cause massive destruction on the ground like in Red Mars. If you have only one space elevator on which practical space travel depends, then its destruction would be economically crippling, but so long as there are multiple elevators, the destruction of one would be just a setback, not a cataclysm.
Well, as the article said, the lower part of the cable would just drift down harmlessly. It would only be the higher parts that would fall fast, and they'd break up in the collapse or burn up in the atmosphere.
Besides, the elevators would have to be built at the equator, which is mostly ocean.
http://en.wikipedia.org/wiki/Space_elevator#In_the_event_of_failure
So an attack on a space elevator could cause some pretty serious disruption of travel, and could be dangerous or fatal to people on the elevator itself or the geosynchronous station, but it wouldn't cause massive destruction on the ground like in Red Mars. If you have only one space elevator on which practical space travel depends, then its destruction would be economically crippling, but so long as there are multiple elevators, the destruction of one would be just a setback, not a cataclysm.
Well, as the article said, the lower part of the cable would just drift down harmlessly. It would only be the higher parts that would fall fast, and they'd break up in the collapse or burn up in the atmosphere.
Besides, the elevators would have to be built at the equator, which is mostly ocean.
I luve the way you make the collapse of a multi million tonnes of structure sound harmless
Seriously though: this kind of structure would have to be constructed with catastrophic collapse in mind and, indeed, the equatorial oceans need to be to the east of the structure!
Edit:
I still don't get it! -what is the big deal about an 'elevator' design when we are almost practially able to build something like a Lofstrom loop today!
trekkiedane said:
I luve the way you make the collapse of a multi million tonnes of structure sound harmless
But the part that's already in the atmosphere isn't that massive or that dense, so it would drift down like paper, as the article says. Remember, the higher-up parts of the cable would have to be thicker because they'd have more weight to support, so the lower part would be the lightest part. As for the higher-up portion of the cable, it would break up into smaller pieces which would burn up in the atmosphere or go flying into elliptical orbits.
I mean, sure, if a lot of that slowly descending cable were to pile up on top of something, it could gradually accumulate to enough weight to crush it. But it would fall eastward so it would probably land spread out rather than piled up, so no single thing it landed on would be that badly damaged.
Look at it this way: A typical hot air balloon weighs several hundred pounds in total. But a deflating hot air balloon drifting down to land on top of your house is not going to do as much damage as a boulder weighing several hundred pounds would do, because it descends more slowly and its weight is more distributed.
In theory it all sounds quite harmless, but when all that material comes crashing uncontrolled down I don't want to be in 'the wrong place' -nor do I want my town encased in thousands of miles of ribbons of indestructible whatever material this structure could be made of.
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Vote Blablover5 -or a mod wins!
Alright already; *virtually* indestructible then.
Still, the loop is the better choice at this moment in our technological evolution.
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Vote Blablover5 -or a mod wins!
Drifting down. We're talking about a ribbon, essentially.
Thanks to orbital physics, it wouldn't fall straight down, but, as already stated at least twice in this thread, it would fall toward the east. No single location would have a large amount of ribbon material piled atop it. Rather, it would be spread out in a fairly straight line. There might be some damage to a few roofs, but I'd imagine the greatest risk of death to anyone is if a part of the ribbon falls across a road and precipitates a traffic accident.
Certainly it wouldn't be perfectly harmless if this happened, but we're not talking a major disaster.
So, a ribbon that has close to no weight will ignore whatever winds might be blowing? -forget it will ya'! -the 'space elevator' has died before anyone ever built one!
the space elevator will be built ten years after everyone has stopped laughing
And if so it will be about two hundred years after the first loop was finished.
(the space elevator has a tendency to kill people on it by radiation which the loop pretty much doesn't)
I would be more concerned about all of satellites and junk below the geosynchronous orbit.
Possession of a space elevator by a nation or group of nations will upset the balance of world economy seriously. The one possessing it will gain access to virtually free energy and raw resources, the secondary nations will become dependant on the first tier nation(s) and nations that does not have access will be proverty stricken(like NK for example).
A proverty stricken dictatortion nation will have ample reason to launch an assault on the elevator and will have just enough technology to do it.
That is just one scenario out of many.
I find it odd that you're using the ribbon's lack of weight to support your fear that it will crush a populated area.
Anyway, the key isn't lack of weight, it's the way that weight is distributed. The ribbon does have a lot of overall weight, but that weight is spread out over a very large linear distance. That means that whatever it rests upon will only have a small amount of weight pushing down on it. But it also means that the ribbon as a whole will have a great deal of inertia and will not easily have its trajectory changed by the wind. Wind blowing on one part of it would have to overcome the inertia of parts hundreds of kilometers away, not to mention the very different winds that might be blowing on it there. I just don't see any realistic circumstance by which the wind alone would cause the kind of pile-up you fear. It could cause a certain amount of twisting and snaking and such, but not enough to cause huge amounts of the cable to pile up in a single location. Any wind powerful enough to affect such a large amount of cable would most likely break it apart into smaller, even less dangerous pieces.
Especially since the engineers would no doubt design the cable to break apart into manageable pieces if it ever did collapse. Of course nobody's gonna build a space elevator that doesn't have a ton of safeguards built in.
If there's only one space elevator, sure. (Something tells me you've read Jumping Off the Planet.) If there are multiple ones, it's not so great a problem.
Because I have no real idea what kind of weight per length we're talking about: a Kg per m means you'd die if it hit your head falling from a few feet above! and then there's wind and then there's the coriolis force and then there's whatever might be fastened to the tether…
There's no way of predicting what kind of damage it could do when it fails at this point.
Depending on HOW it failed/was destroyed. One length of tether might be quite benign falling down, but several pieces of the same with all kinds of different gizmos attached (rails of some sort, temperature and pressure and whatnot measuring devices) a payload…
those might actually be more dangerous, not less.
Of course.
Keep in mind that since the cable would have to support its own weight, all 35,000 kilometers of it, any practical cable design would have to keep the weight per meter as low as possible. And as I already said, the lower reaches of the cable would be the thinnest, lightest portions. I'm not sure you're grasping just how thin and light. We're talking about something that's a millimeter thick at the base -- thinner than twine. That's just not gonna do a lot of structural damage. It would flutter down to a soft landing, and it wouldn't be very heavy at all. Again, maybe it could snarl up traffic and cause a crash, or it could drape across power lines and pose an electrocution hazard. But nobody's gonna die just because it lands on them.
But it is possible to rule out extreme situations like a city being crushed by a pile of twine.
As for Coriolis force, I think that's basically what's causing it to fall eastward in the first place. If there were additional north-south forces, then they would be most likely to hasten the breakup of the ribbon and reduce the danger, not increase it.
Nothing would be probably fastened to the tether except an elevator car, and as discussed, such cars would be designed with emergency descents in mind. They'd have parachutes and such. And even if they didn't, they'd be no more likely to land on a building or a car or a person than a crashing airplane would. Lots of airplanes crash, and they hardly ever kill anybody on the ground. A space shuttle has broken up on re-entry, and nobody on the ground was injured by it. Plenty of satellites and even whole space stations have fallen out of orbit and crashed to Earth over the past half-century, and not one person has been killed as a result. Earth is big and people are small targets in comparison. The risk in a space elevator collapse would be to passengers on the elevator and crew at the geosynchronous station, not to people on the ground.
For the love of Chicken Little, why???? Smaller pieces would weigh less. They'd be slowed down more by air resistance, they'd burn up quicker in the atmosphere, and if they did reach the ground they'd rest more lightly on whatever they landed upon. How could they be more dangerous? Choking hazard?
