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Future of Space Elevator Looks Shaky
lurking_giant writes "In a report on NewScientist.com, researchers working on development of a space elevator (an idea we have discussed numerous times) have determined that the concept is not stable. Coriolis force on the moving climbers would cause side loading that would make stability extremely difficult, while solar wind would cause shifting loads on the geostationary midpoint. All of this would likely make it necessary to add thrusters, which would consume fuel and negate the benefits of the concept. Alternatively, careful choreography of multiple loads might ease the instability, again with unknown but negative economic impacts."
There's also the problem that any ninja can come along and cut the cord, and suddenly you have a $500M paperweight wrapping around the earth tearing a path of destruction.
Place the elevator on the North Pole.
If that doesn't work, we can always use the South Pole.
I'm not saying it shouldn't be done. I guess my point is that the Millenium Bridge is so simple by comparison, yet it needed ~2 years of repairs after opening because of a wobble. People could have been thrown into the Thames, but no big deal, I guess. The space elevator, however, seems so much more prone to failure and with much bigger consequences.
The Rocketdyne F-1 engines on the first stage of the Saturn V had a similar problem early in development. They had a nasty tendency to ring like a bell until they disintegrated (being very loose with this description for the sake of illustration). And they fixed it. The end design was incredibly stable and self damping. With little more than pluck, slide rules, and raw engineering talent. Hell, the entire computer facilities available to NASA at the time (late '50's to early '60's) were less than are available on any engineers desk today.
Solving supersonic flight was another issue of instability. The planes had a tendency to shake themselves apart. We solved that one with essentially no computer help at all (late 1940's).
I have confidence that this problem is solvable. It may not be easy, and may take some genius, but it is solvable.
Just the opposite, actually. The jet pack is closer to what we're doing with space right now, which is strapping huge rockets on a much smaller payload. The space elevator would allow us to use whatever energy source we want to use to get the payload into space (still a significant amount of energy). In addition, it would provide a possible electrical line for electricity to go from space to the earth.
Arguing about protecting it from terrorists is, in a word, retarded. There's no reason that it will be any harder to defend than Cape Canaveral; in fact, it'll probably be easier if it's in the middle of the ocean.
Finally, once we've got one space elevator in place, putting more up will be much easier because of the refined design and the greater ability to send things to space.
just imagine the damage it might cause if the thing were to collapse and land over a populated area.
Depends on how you build it. If you're using carbon nano-tubes, then not much at all. Basically, much of it would go into space, a lot would get burned up on the way down, and the rest would be light enough that it's be more like a bunch of paper floating to the ground instead of a giant steel structure falling down. If it's heavy enough to cause damage, it's probably not going to be a good material to make the elevator out of in the first place.
Honestly, why use climbers? Do we use climbers to go up and down regular elevators? No, because that would be stupid. We have cables attached to the tops of cars, and a counterweight. We should do the same thing with the space elevator. That has the added advantage of keeping all of the moving parts up on the space station (or on the ground, depending on your design), which prevents breakdowns in areas inaccessible repair crews.
Hell, you could probably get away with simply having a big rock somewhere past geostationary orbit tethered to a (very heavy) base station, and simply roll the whole array in and out, with the payload fixed to the ribbon. It would be kept straight by the centripetal force, despite any other forces acting on it. If you HAD to keep it PERFECTLY straight all the time, you could put boosters on the counterweight, but that hardly seems necessary.
Well with an infinite number of monkeys, sorry, science fiction writers, at least one of them's bound to get the correct answer to everything..
Coriolis force as a show stopper? Well, given that:
... let's just say I wouldn't be holding my breath waiting for the space elevator. Unless we can solve the problems involving manufacturing of carbon fibers with the appropriate properties (which is far from a sure thing), worrying about issues like Coriolis on the ascending climbers is like discussing how many angels can dance on the head of a pin.
You do realize that only people with no education in Physics actually thought this would work in the first place.
You can always make a compelling argument when you don't know what you are talking about and are trying to convince the uninformed.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
i thought it was 0 at the equator, just build it there!
IranAir Flight 655 never forget!
He even took it to the point of examining what happens when the terrorists from Earth blow up the link cable that connected the orbital portion, resulting in the elevator 'crashing' down to Mars. He even correctly showed how it would actually wrap around the planet (as opposed to falling straight) and when the final piece impacted it caused a huge crater from the sheer kinetic energy. (like a whip-lash).
Which is, of course, not what would happen. One, the cable must be *incredibly* lightweight per unit length for it to work out at all. Two, any unprotected structure like that would easily vaporize on reentry, even in Mars' tenuous atmosphere. Three, there would be no whiplash, as any unexpectedly strong downforce on the cable, such as "whipping", would simply snap it.
Seen on a Japanese food processor: "Not to be used for the other use."
We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.
Joy! Beautiful spark of the gods!
To use a car analogy, do you think that a fly sitting on your car's antenna will drastically alter your fuel consumption?
Just because some problem have been solved doesn't mean all problems are solvable.
The Kruger Dunning explains most post on