“The ringworld is unstable” 
All this has been mentioned to me, but “comparitively” small cross section as may be, it will still be a massive structure any way you see it. Arthur C. Clarke used diamond in his construction, but it was still HUGE. As for the atmosphere following the earth’s rotation, I seem to recall that the jetstream is caused by the earth’s rotation so you’d still have a very large structure criss crossing through these atmospheric events. Look at it this way, current highrise buildings affect local weather and wind patterns, so much so that in most major cities they don’t allow new construction untill they’ve run tests to see how it will affect the winds/weather (this is from a documentary on the subject. Showed a company specialising in running these tests using a wind tunnel, models and smoke to simulate various wind conditions). These structures will extend the full length (depth? height?) of the atmosphere so the effect will be massively multiplied, it will cut through major wind formations, and while it may not have serious heat buildup, there will still be friction involved.
Are you guys telling me that none of this will make a difference? If so, what is the reasons? (How small/large diameter can you build such a structure to avoid this?)
As for the costs, again, using modern construction as an example, just how much of a benefit do you gain really? The way I see it, you have to expend the energy to get the elevator in place. Plus the actual cost of such a structure would have to be HUGE. So basically, you still have to spend the fuel and money to get the thing in place.
To cross a river you have to spend the fuel and money to build a bridge*. Once you do, though…
The space elevator is the same principle. Once you do it, you reduce all future costs, um, astronomically.
Until anyone else can come up with a way to come back from orbit slowly, cheaply, and safely, a space elevator makes the most sense.
Weather disturbances have been shown to be local, not global, and are a function of cross-section, as well as location.
The real issue is that it is not even slightly practical today, no matter what articles on nanoribbon one links to. But neither is anything else. If we want real space travel for more than the tiniest handful, there is yet no alternative.
- Or a tunnel, jokers.
These two statements appear to conflict just a bit.
As so often is the case between theory and practice.
The OP did mention startup costs.
We had a thread about this a while ago. I said at the time I thought the startup cost would be at least a trillion dollars. In retrospect, I think I was being optimistic.
A trillion dollars might be optimistic, unless some other enabling breathrough happens. That could be cheaper access to space in some other manner, new discoveries in materials, or a new, cheaper propulsion system. If Burt Rutan can come up with a spaceship that can make it to orbit for a fraction of what it costs to send up the space shuttle, then the economics could change dramatically.
The announcement the other day of a simple way to extrude sheets of Nanotubes doesn’t get us the material breakthrough because its not quite strong enough, but it’s close. Incremental improvements in the process might get us to a tensile strength that makes an elevator possible.
There are several big unsolved problems I see with an elevator (other than how to build the structure itself) which would also have to be solved: Protecting it from terrorists, protecting it from collisions with orbital stuff in LEO, and coming up with a climber that can get up the thing with a considerable payload. Work is being done on the climber now under a new NASA prize incentive. I don’t know how likely a collision would be with LEO orbital stuff, or what you’d have to do to prevent it. And the terrorism risk is a real one. No one is going to spend a couple of hundred billion on an elevator if there’s even a slight chance that it will simply be destroyed. We might even have to consider how to protect it in the case of war if we can.
If we can build an elevator for under 100 billion, I think you’d see serious world money being coughed up to fund it. A joint program between the U.S., Europe, Russia, and maybe even China and India could swing one of these, with the U.S. probably picking up the bulk of the tab. That would probably solve the military problem as well. Still have to worry about terrorists. Might be simple as some active point defenses for aircraft and missiles, a 500 mile exlusionary zone for aircraft and ships other than on approved flight plans, and maybe some high level missile defense.
Oh, the other thing necessary before anyone builds this: A reason to do so. This is the big problem with going into space - no one’s really quite sure what we have to gain from it. Other than scratching our itch to explore and learn more about the universe, that is. To most business people, notions of space hotels and mines on the moon still have too much of a whiff of science fiction about them. No one really knows whether people will want to go up into space on vacation for a significant fraction of their personal wealth. Or whether we will ever find anything on a body other than earth that we can’t find more cheaply here on the planet by investing in new mining techniques and new technologies.
The discovery of life elsewhere might do it. If SETI hit a real signal from another civilization, that might wake us up. A significant discovery of a needed resource. Or maybe even discovery of an easy way to colonize the moon, say by discovering water ice in large quantities and closed lava tubes that could be sealed provide living space for thousands of people. They’d still need some reason to be there, but at least we’d have the capability of moving a large work force to the moon if we decide we need to build something big like a huge telescope or a mass driver.
So if we get some enabling new developments like the above, maybe in 50 years we’ll be flinging mass wherever we want to very cheaply.
You need a terminus on the Equator. That terminus has to have access to shipping, and power, and personnel with the skills to build, maintain, and operate all the systems. The number of good places to put one is fairly limited physically, and severely limited politically. Personally, I think you build a floating spaceport first, in the middle of the Pacific, as far from land as possible.
Tris
not according to chaos theory but I dont see how this thing would create some world ending weather effect. according to theory even driving your car affects the weather in places around the world. how much we dont know and never will but the effect is there.
By my calculations, 99.9999999999999999999999999999999999999999999999999999999942 % of all the stuff in the universe exists outside of Earth’s atmosphere.
If we want it, we gotta figure out how to get it.
It’s not true that you need to be at the equator.
I am not a meteorologist, but my understanding is this:
Any structure alters local weather patterns. This is because air (i.e. wind) can’t go through solid matter with any kind of speed.
Big structures have larger influences. Which means you get odd winds around a skyscraper, but the effect is still local.
Add multiple big structures together, the effects of each building interact, which might cause problems. For instance, adding another skyscraper right there might focus the freak winds from these three old skyscrapers right down this street, which will suck for anyone walking there. Still, these are local effects that quickly become invisble when looking at the surronding area as a whole. (Changes in heat retention, evaporation rates, humidity etc. as a consequence of replacing wilderness with a city is another issue, but still mostly local, until your cities start connecting everywhere.)
Now a space elevator will be huge, but apart from the supporting structure and cargo and employee facilities at the bottom, it will be relatively simple. The stuff at the bottom will of course have the effects of any city, but the elevator itself won’t cause complex or lasting effects (disregarding the butterfly effect) on weather. Wind will hit it, split evenly to either side, and meet up again with old friends on the other side, with a touch of turbulence that quickly passes. A tiny, tiny straw in a mindbogglingly huge atmosphere.
Actually, the space elevators the experts are talkiing about are NOT huge.
The whole structure might be 40,000 miles tall (ie pretty darn huge), but the elevators themselves are on the order of the size of a semi-trailer truck, at least at first. Eventually they could grow to be airliner-sized. In the far future, certainly they could be as big as current ocean-going ships, but that’s a long waay off.
As to the support cable (“tether” in the jargon) itself, it needs to be very small to be light enough to support its own weight. Esitimates of cable cross-section range from a few feet to 100-ish feet, with the latter strong enough to lift current cargo ships. Assuming of course, the existence of materials strong enough to support themselves, much less any payload.
The idea that a few truck-sized objects and a string, say, 20 feet in diameter would have the slightest impact on large-scale weather is preposterous. We may as well be concerned about the currrent fleet of jetliners stirring up trouble with their collective wakes.
Now the idea that the weather might have an impact on the tether is a while 'nother thing. It would need to be able to withstand passing through a tornado which itself is several miles tall. That’s a lot of very dynamic and random force to absorb that’s all concentrated over a very small faction of the total tether length.
I think that for something this big and expensive, nanaotubes are just a first step.
This is not something that we would want to have fall out of the sky. Even half of it.
If such a venture is even considered, we will need to address ways of maintaining it.
Nanomachines are probably the answer.
Or at the very least, ‘climbers’ will need to trail and weave additional material onto the cable/ribbon.
I apologize in advance for this sort-of-hijack, but…is it at all possible that the geo-stationary orbit of Jupiter actually lies within the bounds of Jupiter itself? I am noting that the the diameter is something like 11 times that of earth, and it’s ‘day’ is only about 10 hours. Also I believe Jupiter is largely gaseous. I realize Jupiter also has far greater mass than the earth, which I assume changes the calculation of geo-stationary radius. (And I don’t recall the equation) Still, it would be interesting if the geo-staionary altitude were within the outer boaundary of the gaseous radius.
Jupiter revolves once every 10 hours or so. Without doing the math, we can look up the orbital periods for Jupiter’s inner moons to see how they stack up. The closest moon to Jupiter, Metis, orbits Jupiter in about 7.2 hours. The third moon, Amalthea, orbits Jupiter in about 12 hours. So the stationary orbital distance is somewhere between the orbits of Metis and Amalthea.
jovi-stationary, perhaps?
I believe that’s precisely what they plan to do. It will be somewhere out in the Pacific, at the equator, and outside any sea lanes or air traffic lanes. Probably, it will be guarded by a military force, multi-national most likely, that will make sure nothing that isn’t authorized gets within 1000 miles of this thing via air or water. It’ll also be located away from latitudes where you’re likely to encounter hurricanes or tornadoes, and it will be movable so you can physically avoid any dangerous storms that may develop.
Except that, yknow, its kind of pointless having a space elevator if nothing can get near it. Once you want to actually use it for something, then the inspection process is going to be a nightmare because any random bomb put on it will destroy it. It may well be that the cost of getting something up costs 5c a lb but the inspection will cost $1000 per lb.
A large amount of David Gerrold’s Jumping off the Planet is set near or on a working space elevator anchored in Equador. He addresses some of the points mentioned above and describes its construction and day to day operation as he imagines they would be.