Space Elevator Going Up 684
Adlopa writes "The
Guardian newspaper reports on scientists' efforts to realise the space elevator, as first described by Arthur C Clarke in his 1979 novel 'Fountains of Paradise'. Advances in materials science mean that 'a cable reaching up as far as 100,000km from the surface of the Earth' is no longer an impossibility and 70 scientists and engineers are discussing the idea at a conference in Santa Fe today."
Re:this would be sweet (Score:3, Interesting)
Reminds me of.... (Score:1, Interesting)
harnessing the public interest (Score:5, Interesting)
This problem would be neatly solved once the initial expense of the elevator was recouped. At this point it would be much cheaper to send objects into orbit, including people... ride up the chain, get on a space suit, get out on your own nanotube cable and float around 36,000 km above the earth without ever needing to learn how to help fly a space shuttle.
I foresee an enormous tourist interest, to the point that someday several elevators will be sent up exclusively for tourists to use.
What about the static electricity it will generate (Score:5, Interesting)
This thing will could possibly generate HUGE amounts of SE as the atmosphere whizzes past it 24/7. Are there plans to capture and use this electricity or what??
Anyone see the good in this? (Score:1, Interesting)
Looks like the pointy haired boss at work again (Score:3, Interesting)
So how exactly do you come up with a budget for a project that calls for an unknown (but massive) amount of nonexistanium, delivered to orbit no less?
Defending a one meter wide cable below 60,000 feet (Score:5, Interesting)
I know the fiber is as strong as diamonds, and I understand that along it's 100,000 km length it's flexible enough to dodge objects.
But how will they protect it from, well, planes at altitudes below 100,000 feet?
Why I dislike space elevators (Score:1, Interesting)
Space flight should be about space flight. Not about climbing some friggin bean-stalk.
The idea is just so - I don't know - demeaning. It's like cheating in an exam.
caution: atmospheric EMF (Score:4, Interesting)
Re:Boring is ok with me (Score:4, Interesting)
Well, ya, but the purpose of the velocity to begin with is to get beyond the majority of gravity. 25k footpounds I believe. If you want to get a satalite to orbital velocity, it is much cheaper to do so once it is in orbit, free of 98% of the earth's gravity than it is to do this along the way.
Haul it up to 36k feet, and then it takes a relatively trivial amount of energy to get it to a speed for orbit, since it isn't fighting a stronger force (gravity) at the same time. Also, if you are patient, and can take a week or a month to get the unit up to speed, it will take a very small engine (ie: efficient) to build up the necessary speed.
Also, for probes headed toward the moon/mars/space, orbital speed may not be a factor, except as needed to 'slingshot' the unit. IAMARS (i am not a rocket scientist) but it seems to me that you would have to save 70% of the energy needed by going to 36k km slowly, then positioning. The most important feature is that not only do you save the weight of the extra fuel, but you also the save the extra fuel needed to move that extra fuel. It may actually be more than 70% of the fuel.
Another interesting question: What fuel is used for getting the unit into space (36k km) to begin with: To power the elevator? Obviously it will not be rocket fuel. The cool thing is, if they used technology [scjai.com] that harnesses [pacpubserver.com] ocean waves [dailycal.org] then they would not need oil generation units
The secondary benefits of this space elevator could eventually be greater than just cheaper satalite launches.
Re:Not an impossibility? (Score:3, Interesting)
Any one know of any projects using an organic approach instead of a chemical approach (which is what I think is being used now?)
Re:what about Newton's third? (Score:4, Interesting)
The question I want to know is what are the osilation modes going to look like. You have a massive string under tention, it is going to vibrate. I'm sure you could figure it out if you had some clue as to the properties of the material.
Re:Looks like the pointy haired boss at work again (Score:5, Interesting)
Re:Going up... (Score:3, Interesting)
I know you were just joking, but I found that number kind of put it all in perspective for a second.
What I don't understand... (Score:4, Interesting)
Slashdot - Texas Scientists Spin Carbon Nanotube Fiber [slashdot.org]
Other promising research:
Slashdot - Scientists Crack Silk's Secret [slashdot.org]
and
Slashdot - Nanotube Applications Grow And Grow [slashdot.org]
Maybe they did discuss all this and more at the conference - I would like to hope that these scientists and researchers are aware of what is going on in this far-flung field. I only wish they would have made mention of this stuff in the article for the common man, to show that it wasn't all so much "hooey" - that it is something which may be inevitable, and will happen sooner than we all expect.
We (all of mankind) are rapidly moving in a very funky direction, technology-wise. We have carbon-nanotube fibers. We are looking into other advanced fibers and fiber processes. We have found sea-creatures that make insanely great fiber optic fibers (and with the other stuff, we will probably be able to replicate the process very soon). The gains in communications alone will cause a lot of other gains to be made, because of distributed processing amongst far-apart supercomputing centers that need more bandwidth than they already have (and they have a crapload, but not as much as they want or need). Such fibers may help in the optical-computing dept as well. Remember also the stories of "growing diamonds" - that are so pure they are almost impossible to distinguish from real diamonds - and they have DeBeers quaking at the possibilities to their "markets", maybe destroying them. But these companies don't want the diamonds for prettiness or money (well, they want them for the money, true), but to be able to use them for the substrate of computer chips, instead of silicon, for higher speeds and better heat dissipation.
Couple that with all the other "funky" advances we have seen - we are all being dragged in a very wierd direction, speeding up the computing and learning capacity of all involved (and even if you are at the edge of the network, like most of us are here, and not where the action is, you will still be pulled in)...
I don't know where to go with this - except that our current distopia (and if you don't think we are living in a distopia, one every bit as scary, strange, and awe-inspiring as science fiction can come up with - you haven't been paying attention) is going in a new and strange direction, strangely reminiscent of what the "early-years" (which are only touched on) of Neal Stephenson's "Diamond Age" might have been like.
This is all strange shit, yet very few of us are even seeing it or thinking about the real implications, for some reason...
Re:harnessing the public interest (Score:3, Interesting)
The ascent is going to be very very slow. Imagine going at 100km/h, a speed that would impress most normal elevator designers. 15 days for the ascent, 15 more for the descent. (Admittedly the descent could be done quicker).
It isn't going to be even close to 15 days to get to the top. Some very simple physics tells us that if we accelerated at 1 g for 1 second we would be traveling at a velocity of 9.8 meters per second (gravity on earth equals 9.8 m/s/s). If we then traveled at that constant speed we would reach the top of the cable in a little more than 11 days (do the math and see). Since we are operating under the influence of the earth's gravitational well we couldn't just accelerate for one second and then coast at constant velocity.
However, much more likely is that we will accelerate the "elevator" at 1/10 g to the halfway point and then decelerate it at 1/10 g to the top. And if we have two "elevators", one going up and one going down, it will be basically a system with little to no external energy requirement. Initially we have to invest the amount of energy required to lift one elevator and the other components needed for the station in orbit. Then we have to expend the energy to put the cable in place. Once that is done we start the top elevator down and voila we have the energy to start the bottom elevator accelerating up. There's a bunch of engineering involved to do this, but it's overall pretty basic physics.
If you do the math you will see that if we accelerate at 1/10 g to the halfway point, then decelerate at 1/10 g to the top, it will take a very short time to travel 100,000 km to the top of the elevator.
Let's round 9.8 m/s/s to 10 m/s/s to make our life easy. This isn't accurate, but it makes the equations much simpler. So, 1/10 g is 1 m/s/s. The formula for velocity while accelerating is:
.5 * 1 m/s * t^2
:-).
v=a*t where v=velocity, a=acceleration and t=time.
So, while accelerating at 1/10 g after 10 seconds we are traveling at a velocity of 10 meters per second, or 36 kilometers per hour, or 21.6 miles per hour. The next question is how far have we traveled? That formula is:
d=.5*a*t^2 where d=distance.
So at the end of those same 10 seconds we have traveled 50 meters. So, how do we figure out how long it takes to get to the halfway point? Simple substitution:
50,000 km =
Now solve like any other algebra equation. Remember to convert kilometers to meters.
t^2 = 50,000,000/.5*1
So t= 10,000 seconds, or roughly 2.8 hours traveling at a velociy of 10,000 meters per second (36,000 km/hr or 21600 mph). When we decelerate everything becomes negative and it takes the same amount of time to go from a velocity of 36,000 kph to 0 as it did to accelerate to that velocity. If you aren't sure just substitute a negative value for acceleration of -1 m/s/s and check me
Bottom line, with a 1/10 g acceleration you will reach the top of the "elevator" in less than 6 hours, assuming constant acceleration. In all likelihood we won't accelerate constantly because our vehicle would burn up in the atmosphere. Probably we will boost to a constant velocity, flip at the halfway point and decelerate when needed. Even doing that we will reach the top in less than a day.
And we will generate all the energy needed for acceleration and deceleration within the system. Pretty neat!
Re:harnessing the public interest (Score:4, Interesting)
Eek. We have enough trouble building a horizontal railway that travels faster than a few hundred kilometres per hour--now you want us to build a vertical one that reaches a speed thirty times greater? One little hiccup in your track mechanism (presumably some sort of magnetic suspension) and the moving cargo drags against the elevator cable at ten kilometres per second. Suddenly, you have a much shorter cable...
I'm prepared to accept a slow and stately climb at four or five hundred km/h, even if it means it will take ten days to ascend.
I don't get it (Score:4, Interesting)
What about little space junk? (Score:4, Interesting)