Still More on Space Elevators

parseexception writes "The NYTimes is reporting Not Science Fiction: An Elevator to Space. Not a whole lot of technical detail but good read. It is interesting to see alternatives to current space technologies being explored."

Happy Google linky no reg

[borgboy]

Not Science Fiction: An Elevator to Space [nytimes.com]

Fountains of Paradise

[Henry V .009]

Clarke's Fountains of Paradise [amazon.com] is a wonderful book. It presents the basic physical problems of a space elevator and some ways to solve them (and it has a great plot too).

Right now, as Clarke envisioned, carbon nanotubes are the only engineering material that could be used to make this elevator. The basic technological question is whether we will ever be able to make cheap and long nanotubes. Despite the enthusiasm for a space elevator in the NYT article, we really have no idea how to do that. And any cost estimates like "$6 billion" are very immature without that kind of detail.

Re:Fountains of Paradise

[Birger Johansson]

Space elevators are one of three basic "space tether" concepts, and it would be logical to start with more humble objectives.

The simplest form of a space tether is essentially a high-tech version of that bronze-age weapon, the sling. A tether for sending satellites to higher orbits, or spacecraft on lunar or planetary trajectories can be achieved with *existing* materials, like kevlar or spectra.
This form of tether concept is being investigated by NASA.
A second form of space tether -the hypersonic skyhoo

Cool

[Bob Vila's Hammer]

This is the best thing for the success of the project. All it really needs is publicity. The Space Elevator is a solution to so many problems with current space technology that it should be operating right now.

The good publicity drumming up the imaginations of people in this country can only get this thing built faster. The technology needed for the ribbon is almost perfected. In 5-10 years or so (maybe after all this terrorism and war bs has ended) this thing might really get off the ground and the m

Re:Cool

[Flingles]

"this thing might get off the ground"

pun intended? :)

Re:Cool

[Bob Vila's Hammer]

haha, absolutely. :-)

All we need is for the ball to get rolling...

[LinuxMan]

Once we have a number of people going into space, and it builds a travel industry around it, suddenly we will see lots of innovations like the space elevator, etc. become not only practical but quite cheap. If only the government used computers, computers would cost a fortune, but since there is such competition, we have computers that sell for $300 or less now. If that same concept is applied to space travel, there WILL be competition, and there WILL be new better, cheaper ways to get up there, which may or may not involve the space elevator.

My theory has always been that once we have a hotel on the moon, due to it's gravity, people will not have as much of a hard time adapting to it for their vacation, more hotels will open up in competition. Initially, a lot of money would be spent setting up, but the costs of everything would continue to go down. Before we knew it, we would have faster propulsion technologies, better gravity-like technology, and we would be off to Mars for our next resort, resulting in even better competition for innovation.

space elevator [amazon.com]

Re:All we need is for the ball to get rolling...

[Ruy-sun]

NASA is trying to artaficaly boost competion in the usa's space indevers. NASA is hold a contest for the first group of people using a 3 million dolor buget. (not sure the about of prize money) to reach space with 3 people for the competion they do not have to go all the way in to orbit just very close. The consept behind the compation is to see what new ideas are made. and if one of the groups gets a good shutle (or whatever) and patents it then that would boost technologies, but also the tourist base,

Space elevator old news?

[GeoGreg]

Hasn't the confectionery industry already done this [amazon.com]? I hope these NASA folks know to watch out for Vermicious Knids.

Space elevator news

[Quaelin PoD]

I help run a space elevator news / portal site:

LiftWatch.org [liftwatch.org]

We've got links to this story and many more... plus reports on the recent SE conference in Santa Fe, discussion forums, image galleries, etc. Check it out!

I've put in a request... hopefully our headlines will be added as a slashbox here soon.

This "Space Elevator" seems cool and all, but

[the_Upsetter]

Funny... [slashdot.org] I [slashdot.org] can't [slashdot.org] think [slashdot.org] of [slashdot.org] a [slashdot.org] single [slashdot.org] thing [slashdot.org] to [slashdot.org] say [slashdot.org] on [slashdot.org] this [slashdot.org] topic. [slashdot.org]

Not [slashdot.org] one [slashdot.org] thing. [slashdot.org]

Re:This "Space Elevator" seems cool and all, but

[torpor]

My middle mouse button thanks you, sir.

From signage found only on California elevators...

[mbstone]

"If the elevator gets stuck, do not become alarmed. There is little danger of the elevator running out of air. Then again...."

kind of funey

[Ruy-sun]

I have thought of this beffor. It's intresting though what made me thank of it is in the anime Armitage: Dule Matrix they use, one and the finaly fight takes place there. hmmm. I wonder if the scientist who came up with this idea saw Armitage too?

Re:kind of funey

[zero_offset]

You'll be pleased to know there is a simple answer to your question: No.

Balance

[CowboyRobot]

In addition to the other MAJOR engineering challenges that this project would require, how will the satellite at the other end of the elevator stay in place? I understand that if it has the proper mass and is at the proper altitude it will orbit directly above the base station - but what happens when you deliver a 13-ton payload there? Won't all that additional weight cause the satellite to swing forward?

Re:Balance

[Patrik_AKA_RedX]

A 13 ton payload doesn't add much mass to a multi Mton rock. I guess they'll need to do a few course correction every nth time some cargo goes up.

Re:Balance

[tiled_rainbows]

I've read stuff suggesting that you could have the elevator going up to Geostationary orbit, but then continuing past that point to a big rock or something further out. The big rock would be dragged round at geostationary-orbit-speed but, being further out, would have a centrifugal pull on the cable, keeping it taut. You might want to have the elevator cars going 'up' to this counterweight (although once you passed the geostationary point it would feel more like you were going down) as it would have a weak

Re:Balance

[barawn]

The shuttle's orbit would change if it grabs a satellite, unless the center of mass of the extended "satellite/shuttle" system is at the same altitude as the shuttle was originally.

If the shuttle approached the satellite from along its orbital path (the path of its velocity) or the path perpendicular to it, then it wouldn't change (in front of/behind it, or left/right of it). If it approached along its radial vector, it would change (above/below it).

If it grabbed along the radial vector, the shuttle and t

Re:Balance

[Anonymous Coward]

No.

Orbital paths are dictated by velocity and altitude.

Any objects,regardless of differances in mass, at a given velocity and altitude will orbit along the same path.

Re:Balance

[barawn]

Well, close.

Orbital paths are dictated by velocity and altitude of the center of mass.

Move the center of mass, you change the orbit of the object. So the point that he made is valid, if not for the reason he thought (or you thought that he thought).

This isn't a problem in this case, as others have pointed out, for many reasons. First, it's a trivial mass compared to the elevator mass. So it's not going to significantly change things at all.

Second, even slightly altering the center of mass like this wou

Re:It's all about balance!

[barawn]

Actually I would suggest some liquid movement tanks high and low on the counterweight to maintain the balance without actually having to shorten the cable/distance to the balance point. Or you could have some type of elevator/freight system moving large plugs/masses of rock up and down to do the job. Better yet, both, having a dual system (or even ternary) would make sense considering the importance of balancing the system...*GRIN* I would do a great deal of work making it as foolproof as possible cause go

Re:It's all about balance!

[barawn]

...*GRIN* So you should be able to make the trip in 6'ish hours. That

6 hours? No way. 2 weeks, nominally.

The whole reason a space elevator wins over a rocket is because you can avoid air resistance by going slow. In 6 hours, you might as well be using a rocket. You're talking about 60,000 km, so roughly 10,000 km an *hour*.

There's another problem with a 6 hour trip, too - the speed of sound in the elevator produces about a 7 hour natural vibration. A 6 hour trip means that you're actually travelling su

Re:It's all about balance!

[barawn]

Once you're outside the atmosphere there are no outstanding reasons for not moving faster. That is why I mentioned magnetic drive/coupling instead of any physical connection. And of course carbon nanotubes can be configured to carry power, it should also be relatively simple to configure part of the elevator as a track for a magnetic linear accelerator. No inefficient rocket power required (although to be honest I'm not sure what the efficiency of a linear accelerator is).

Damage to the ribbon is a good re

I hope

[cbmeeks]

to be the first to stand in that elevator...and press all the buttons so that the next guy will have to stop at every port before the 60,000 mile trip is over. hehehe cb

escape velocity?

[eggoeater]

So how does escape velocity play into this? If we can leave the earth without reaching an escape velocity then (on a very theoretical level) could we ride a space elevator out of the event horizon of a black hole? I realize there's a million other reasons why we couldn't get near a black hole, hawking radiation, strong gravity would rip us apart, etc. But you could also apply this argument to other things, like going into Jupiters' upper atmosphere which has bucko gravity. I was taught escape velocity wa

Re:escape velocity?

[Planesdragon]

So how does escape velocity play into this?

At a very basic level.

Remember that the Earth rotates--right now, you're moving at, what, about 2,000 mph? As you go straight up, relative to a point on the surface, your speed increases because you're still completing one rotation / day. Once you get up to geostationary orbit, you've got (at least) the necessary escape velocity. (I also suspect that e.v. goes down as altitude increases, but I'm not certain.)

As for the black hole--if you managed to place a ca

Re:escape velocity?

[barawn]

Remember that the Earth rotates--right now, you're moving at, what, about 2,000 mph? As you go straight up, relative to a point on the surface, your speed increases because you're still completing one rotation / day. Once you get up to geostationary orbit, you've got (at least) the necessary escape velocity. (I also suspect that e.v. goes down as altitude increases, but I'm not certain.)

No. Escape velocity is what you get when you set kinetic energy = potential energy. Kinetic energy is T = 1/2 mv^2, po

Re:escape velocity?

[Planesdragon]

Ah. So geo. orbit isn't escape velocity, it's just about exactly shy of escape velocity. Gotcha.

There is no way you could build a space elevator out of a black hole

Given everything we know, yes. But "it's impossible" has never stopped hypothetical science fiction before

Re:escape velocity?

[barawn]

My understanding (and flawed it probably is), is that the event horizon and the singularity are quite different things. I'll agree what you state is likely true in reference to the singularity but as for the event horizon I must disagree.

They are. The event horizon is not a true discontinuity in space. To an observer moving inward, nothing weird happens at the event horizon. The singularity is a discontinuity in space, and an indestructible 'observer' would see something weird happen at the singularity.

H

Re:escape velocity?

[barawn]

I was having real trouble thinking about this until you mentioned that spacetime itself is moving/accelerating

I don't remember saying that... that's definitely not true. The Schwarzschild solution has an event horizon even if it's static.

The problem is that you've got to worry about reference frames quite a bit here. For the observer at infinity, space and time seem infinitely stretched out as you approach the event horizon.

For the observer falling INTO the black hole, nothing weird happens at all near