Space Elevator

[Adamaja456]

http://www.cnn.com/2008/WORLD/europe/10/02/space.elevator/index.html?iref=mpstoryview

[Oni-Paranoia]

Re: Space Elevator

Pretty sick, too bad we most likely wouldnt see it finished (if it ever starts)

[OrganisM]

Re: Space Elevator

Crazy. Time to look at today's sci-fi and imagine if any of those things could be in development in the future.

[Breakdown16]

Re: Space Elevator

That's cool. Science fiction becomes reality; the title slightly reminded of Charlie and the Great Glass Elevator. I sure hope I'm alive long enough to see this (not likely though).

[EAGAMES]

Re: Space Elevator

Indeed, if successfully built, the space elevator would be an unprecedented feat of human engineering.

Ya, but I'm not getting in it.

[Kekeb]

Re: Space Elevator

That's one thing that annoys me the most; won't live to see some of the greatest inventions or feats.

EDIT: I'm thinking maybe another century or so and EDIT:[more like] "serious" engineering might happen.

[foilman8805]

Re: Space Elevator

I'm a bit skeptical about it to be honest.

Couple things that don't come together here:

1. How to slow everything down once it gets to space...the friction involved in slowing down something that needs enough velocity to actually escape orbit in huge. HUUUUUUUUUUUUUUUUUUGE. It's an incredible amount of energy...more than any of us can reasonably fathom, and slowing down something with that kind of momentum is not an easy task. (My best guess would be electromagnetism...)

2. The g-forces associated with leaving orbit, and in a related sense, the escape velocity of the elevator. There's no way it's going to be a leisurely ride at a comfortable speed like on a monorail...it just can't be. It has to happen quickly, otherwise gravity will overcome the elevator and force it back down to earth. (I'm thinking of a conventional launch situation here, so perhaps there are ways to get out of orbit at a slower speed.)

3. I've seen carbon nanotubing, and it's seriously incredible material, but to think that we need something 4 times as strong as carbon nanotubing is just mind boggling. The tensile strength of carbon nanotubing is over 60 GPa. Compare that to carbon fiber which hovers around 5.5 GPa - carbon nanotubing is more than 10 times as strong as carbon fiber (imagine that!), and we need something 4 times as strong as carbon nanotubing? Don't forget that this material has to stretch however many miles it is to get into orbit (62 miles in the air I believe). Maintaining material properties over a distance like that is stupidly difficult.

Anyways, that'll be some serious engineering in its own right if a material is created that is strong enough to be used for a space tether, let alone actually create a functional space tether that can launch and slow a payload down.

Sorry for the diatribe, but I'm working on my Master's in aerospace engineering, so I felt like I could actually talk about the topic.

[Adamaja456]

Re: Space Elevator

We're just seeing the tip of the iceberg in advancements in technology. We cannot even imagine what will be invented in 100/200/500 years.

i honestly think we are going to invent some way to deal with those issues foilman. it might take 200 years before the right brain contributes to it, but think of all the amazing technological advances over the last 50 years. It might be impossible now, but the answer might be in the palm of someone's hand in the future
<3

[Psychotik]

Re: Space Elevator

For now, space elevators seem to advanced for our technological knowledge.
I would like to see those transportation tubes from futurama though .

[foilman8805]

Re: Space Elevator

Space tethers will happen before tube travel.

[Adamaja456]

Re: Space Elevator

12 mile tether ftw!

http://www.youtube.com/watch?v=azjP1Aw6NBw

[ichliebekase]

Re: Space Elevator

I've been learning about the physics of escape velocity and how much you would need to escape the atmosphere. It actually takes alot to get just a few pounds through the atmosphere, let alone people and an entire elevator.
But definately a good show for futurama. If I see it I'll watch it

[foilman8805]

Re: Space Elevator

Oh, I see JKPolk.

[JKPolk]

Re: Space Elevator

Foilman, while I don't think the idea of the space elevator is actually feasible, the problems you listed aren't actually included.

1. How to slow everything down once it gets to space...the friction involved in slowing down something that needs enough velocity to actually escape orbit in huge. HUUUUUUUUUUUUUUUUUUGE. It's an incredible amount of energy...more than any of us can reasonably fathom, and slowing down something with that kind of momentum is not an easy task. (My best guess would be electromagnetism...)

The escape velocity for earth is huge, yes, (11,800 m/s) but that's only the amount of kinetic energy required to escape. Really, you can just go out at 60, 70 mph as long as you have a constant force associated with the movement. Technically you don't even need a constant force, but for ****s and giggles we'll ignore that for now. The only real issue with leaving orbit is reaching a certain point with a certain energy, and that point is the sphere of influence.

Plus if you wanted to get fancy you could just use the moon to slow you down rapidly without killing yourself, just counterorbit it and you'll have the opposite of the slingshot effect made famous in Apollo 13.

2. The g-forces associated with leaving orbit, and in a related sense, the escape velocity of the elevator. There's no way it's going to be a leisurely ride at a comfortable speed like on a monorail...it just can't be. It has to happen quickly, otherwise gravity will overcome the elevator and force it back down to earth.

Same as above, it doesn't have to happen quickly as long as a constant force of (g+delta)*mass where delta is any positive value is applied to the elevator.

3. I've seen carbon nanotubing, and it's seriously incredible material, but to think that we need something 4 times as strong as carbon nanotubing is just mind boggling. The tensile strength of carbon nanotubing is over 60 GPa. Compare that to carbon fiber which hovers around 5.5 GPa - carbon nanotubing is more than 10 times as strong as carbon fiber (imagine that!), and we need something 4 times as strong as carbon nanotubing? Don't forget that this material has to stretch however many miles it is to get into orbit (62 miles in the air I believe). Maintaining material properties over a distance like that is stupidly difficult.

This is pretty much the entire reason which I feel that the elevator is absurd. There's a new plan being put into motion which will, in layman's terms, put gas stations into orbit for the shuttles. With that put into place the cost of launches will be 1/20th of what they are now.

Overall, I just disagree with your arguments that "the escape velocity is this and so it won't work," the escape velocity is only listed as that because of the conservation of energy equations being written from earth's surface with only a launch speed specified.

[foilman8805]

Re: Space Elevator

Good idea to use the moon to slow your payload down. I definitely overlooked that, but how much more time would that add to a journey? Days? Don't know if it would be cost effective to take a trip around the moon.

Assuming this can even happen, of course, what would you recommend for the payload to get into orbit?...a huge, slow burning thruster? I guess I'm just stuck on a conventional launch situation which uses heavy thrusters.