Space Elevator

[Crow T Robot]

I was wondering what everyones thoughts were on the viability of the space elevator.

I know this pops up once in a while and while it seems to work on paper, from an actual engineering standpoint it looks daunting to say the least.

Recent Article in Wired:
Wired Magazine"

and an interesting report from NASA:
Space Elevator

[SpacedOut]

Interesting Stuff - but my guess is that the $10 Billion estimate is probably off by at least a factor of 10. It will probably cost at least $10 Billion just to do all the feasability studies.

[Lexx_Luthor]

Thanks!!! A friend would like to see that.

Now he can. !!!

Feasability. How many Feasability Studies did Kennedy's administration conduct before he "mooned" America in his 1961 speech?

[Eirik]

The space elevator popped up on the local news here in Seattle last night (KING-5) as if it were a reletivly new thing, but I recall that a couple Seattle companies were talking about getting some funding for research months ago. I'm not sure if the Columbia disaster caused them to issue some new press releases or what.

From what I understand, though, if it could be done it would drop the cost of going into orbit rather condsiderably...

[Rich]

Well, it would drop the one-time launch cost, but what about the cost per launch over the life of the system? If it cost $10 trillion (an admittedly far-out and unsubstantiated guess) to build when would you even reach a break even point? I know they said ten billion, but that's just laughable (are they calculating that budget in 1945 dollars?).

There are still many, many technical hurdles to overcome. No one can yet manufacture carbon nano-tubes, the preferred building material, on a large scale. No one knows, for sure, how to bond such a large nano-tube construction. There is no sure fire way and no cost estimate for an anchor. No one knows exactly how upper atmosphere weather, especially poorly understood electrical phenomena, would affect such a structure. No one knows how safe a carbon nano-tube structure would be if it gathered a large charge from electrical phenomena or friction from the atmosphere. No one knows how to protect such a structure against electrical discharges or sources of fire (carbon nano-tubes are highly conductive and eminently combustible).

In short there are a lot of unresolved issues. Decades worth of technical work remains to be done, even then I'm sure we'll run into interesting problems we never even thought of. Barring massive political/industrial/commercial backing on the scale of the Manhattan Project I wouldn't plan on riding on a space elevator even in your children's lifetime. I'd love to be wrong, but I just don't see it.

[Doodler]

I think the recent issues with the shuttles may bring the idea (at a small scale) closer to the forefront. Even if they aren't building it within a human lifetime, they can at least start developing the infastructure. Think nanotubes make a great elevator cable for satellites, how many bridge builders would sell offspring and internal organs for access to this stuff? Material applications need not only work in space. If they can market the potential, they could indirectly accelerate industry towards their goal. Its just a matter of schmoozing the right people.

[Simon]

On 2003-02-05 15:09, Rich wrote:
Well, it would drop the one-time launch cost, but what about the cost per launch over the life of the system? If it cost $10 trillion (an admittedly far-out and unsubstantiated guess) to build when would you even reach a break even point?

Well, call it $50 trillion for the cost of the system, and say it reduces lift costs from $22,000 to $50 (not impossible by any means; all it'd cost is electricity and maintainance). So it'd have to lift 2,278 tons to pay for itself. I think that's roughly equivilant to the mass of all the payloads lifted into orbit by the Space Shuttles to date. Of course, it could probably lift that mass in relatively short order.

Someone double-check my math, willya? [img]/phpBB/images/smiles/icon_wink.gif[/img] And rustle up some investors while you're at it.

[Rich]

Depends what's the $50 for, per ton or per pound?

Even if it's $50/ton that's still $50,000,000,000,000.00/($50/ton)
= 1 trillion tons...

That's a lot...

[Rich]

On 2003-02-05 15:50, Rich wrote:
Depends what's the $50 for, per ton or per pound?

Even if it's $50/ton that's still $50,000,000,000,000.00/($50/ton)
= 1 trillion tons...

That's a lot...

The flip side is that you could put some very large payloads into space. I would think the pay-off would be directly proportional to the lift capacity. If you could built the entire ISS on the ground and lift it, assembled, in one shot... Whoa!

I'm sure that would significantly increase the building cost while driving down a one-time lift cost independent of construction costs and overhead (no pun intended).

[Edit: Damn my spelling]

<font size=-1>[ This Message was edited by: Rich on 2003-02-05 16:00 ]</font>

[Doodler]

Is that unreasonable considering the potential operational lifespan of the elevator? Aside from replacing worn out cars, the cable itself should be EXTREMELY long lived, if its designed properly.

[SeanF]

On 2003-02-05 15:43, Simon wrote:

Well, call it $50 trillion for the cost of the system, and say it reduces lift costs from $22,000 to $50 (not impossible by any means; all it'd cost is electricity and maintainance). So it'd have to lift 2,278 tons to pay for itself. I think that's roughly equivilant to the mass of all the payloads lifted into orbit by the Space Shuttles to date. Of course, it could probably lift that mass in relatively short order.

Someone double-check my math, willya? [img]/phpBB/images/smiles/icon_wink.gif[/img] And rustle up some investors while you're at it.

At a savings of $21,950 per unit, you'd have to lift 2.278 billion units, not 2.278 thousand, to save $50 trillion dollars.

[RafaelAustin]

I've always loved this concept since reading about it Foutains of Paradise, but admittedly it's a technology still 100 years in the future. And I think that's more because of the magnitude of the project, not necessarily the technical aspects.

Here's a previous disscusion on BABB about this with some links.

And I think I remember that the lifting capacity wouldn't be greater than that of the Shuttle, but the frequency would multiply (2-4 lifts per day??). There are all sorts of ideas about using the platforms built on it for satellite stations, observation decks and hotels, etc.

In addition to the problems mentioned before, the harmonics aren't well understood and I believe someone on this board claimed that it's not stable at all.

Regardless, it's a concept to dream and plan for and who knows, maybe someone eventually will have the manufacturing and public relations expertice to get it done.

[Crow T Robot]

Apart from engineering.....
It seems to me that the cost to orbit drives the whole thing. It seems to me the way to calculate payback on investment is to compare the new way with the old way.

Current cto is, what, around $20,000/lb.
At a $50/lb cto the payback is $19950/lb
Which works out to $100,000/ton vs. $40Million/ton with the Shuttle, a savings of $39,900,000/ton.

Now assume a $50T cost to build the Space Elevator.

With a cto of $50/lb you would need to launch about 1.253M tons of stuff to break even on the project based on previous cto vs new cto. This works out to about 39,782 Shuttle launches.

By the way if launch costs were cut to $50/ton you would still need to launch 1.250M tons or 39,682 Shuttle launches.

If the cost to build is $1T then we're looking at about 795 Shuttle launches worth.

At $100B 79.5 Shuttle launches and
at $10B 7.95 Shuttle launches.

If costs are in the $50T range it would be pretty difficult to justify but at $1T and lower I think a good case can be made to spend the money if the engineering is there.
If you bring launch costs down to $50/lb - $50/ton you'll have more business than you can handle even with a launch window every hour or two.

Ex. At $50/lb my big butt could get into orbit for about $15,000 that's less than I paid for my Jeep, and at $50/ton it works out to $7.50, a normal sized person would be @ $4.25. I spend more than driving to work each day.

If they can get cto to $50/lb most people can afford to head to orbit at least once if not several times, and I can prety much guarantee millions would sign up. At $50/ton anyone that wants to go can afford it, even the beggers on the street corner can scrounge up 4 bucks.

[traztx]

Is the current shuttle a good comparison? How does Soyuz compare to Shuttle for cost? What about Atlas?

How fast can an elevator ascend? Remember, it has 35,786 km. Imagine lifting cargo at even 100 km/hour (I don't know any elevators that fast)... will take 15 days to reach geosync.

Is the elevator useful for any other orbit lower than geosync?

Still seems to me like something way far out of my lifetime, but who knows, technology sometimes takes a leap!

[sacrelicious]

how can it work though?

1) the top of the ribbon would be anchored to nothing but microgravity space. the lower portion would have the burdon of more and more gravity the lower it goes. it reminds me of the old cartoon cliche of someone trying to climb a rope that has been severed from what it was tied to, each pull only bringing the rope down more.

now you might argue that the top platform would have rockets to provide a counterforce when things are being brought up. not having any concept of fuel weight/thrust ratios, I would be unable to debunk that, so I will assume that it is reasonable. however, the ribbon itself, no matter what ultra-light material it is made of, would likely exert more force by itself than even the largest cargo that it would carry. this means that you would have to be burning rockets to counter the force, not only when you are lifting, but 24 hours a day, seven days a week! now I'm no mathmetician, not by a longshot, but it would seem to me that burning that burning any fuel nonstop like that would have to cost a hell of a lot more than our current shuttle system, and likely multiplied a few times over!

2) fragility: it would not take much for a terrorist, or even a rather skilled prankster, to sever the ribbon. one homemade missile could do the trick nicely, and considering the rather large target area presented, it seems to me that fighter cover (another added expense, btw) could only even dream of 75% effectivness in such a situation.

then there is weather to worry about. all you need is one hurricane to destroy the whole thing. even regular winds could force the top platform into an entry trajectory.

now please tell me how I might be wrong about these things, cause I can't figure out how profesional scientists could actually deem this reasonable.

[daver]

On 2003-02-05 18:14, sacrelicious wrote:
how can it work though?

1) the top of the ribbon would be anchored to nothing but microgravity space. the lower portion would have the burdon of more and more gravity the lower it goes. it reminds me of the old cartoon cliche of someone trying to climb a rope that has been severed from what it was tied to, each pull only bringing the rope down more.

Imagine a rope that goes from some spot on the equator up about 60,000 km or so. Now, imagine you're on a spot at geosynchronous altitude. You experience no net force--you're in orbit. Head "down" (towards earth). The further down you go, the more weight you feel (pulling you towards the earth). OK, climb back up to geosync. Now, head "up" (away from earth). The further up you go, the more weight you fell pushing you away from earth (as you head towards the earth, the gravitational force increases and the centrifugal force decreases; contrariwise for heading in the other direction).

So the trick is to put enough mass on the far end of geosynchronous orbit to overcome the weight on the nearside.

[some speculation deleted]

2) fragility: it would not take much for a terrorist, or even a rather skilled prankster, to sever the ribbon. one homemade missile could do the trick nicely, and considering the rather large target area presented, it seems to me that fighter cover (another added expense, btw) could only even dream of 75% effectivness in such a situation.

Yep, this is a problem. The proposed site is a long way from anywhere; it would be difficult for a terrorist to launch a missile at it. However, it would be possible for them to put a bomb in a cargo container and have it sent up the tether

then there is weather to worry about. all you need is one hurricane to destroy the whole thing. even regular winds could force the top platform into an entry trajectory.

A hurricane wouldn't destroy the whole thing; it might blast the very bottom. The rest of it would go into a higher orbit, they'd have to repair the bottom few miles and go for a reattachment.

One of the criteria for the proposed base station site was its freedom from bad weather, but there will always be flukes.

now please tell me how I might be wrong about these things, cause I can't figure out how profesional scientists could actually deem this reasonable.

Thank you for asking (i'm serious here. I've seen plenty of postings that claim flat out that it is impossible (usually for pretty bogus reasons) and call everyone involved with such a thing charlatans and con men. It's refreshing seeing somebody actually ask if it's reasonable). There is a website (i don't have it handy, but it's been posted, both here and on some Yahoo boards on this topic).

[logicboy]

Come and get your Carbon Nanotubes only $50 - $100 per gram

MERCORP

Carbolex

CNI

[Mainframes]

On 2003-02-06 09:41, logicboy wrote:
Come and get your Carbon Nanotubes only $50 - $100 per gram

MERCORP

Carbolex

CNI

What's the quality of those nanotubes though? Did an undergraduate project on Carbon Nanotubes a couple of years ago and the price varied greatly with the production methods.

The production methods determined the quality of the nanotubes and physical properties such as orientation of tubes ie lined up or random, overall length, no. of imperfections (a chain is as strong as it's weakest link) plus whether they were multi-walled or single-walled, and chirality(affaects electrical conductivity).

Anyway i'll shut up now....

[logicboy]

What's the quality of those nanotubes though? Did an undergraduate project on Carbon Nanotubes a couple of years ago and the price varied greatly with the production methods.

The production methods determined the quality of the nanotubes and physical properties such as orientation of tubes ie lined up or random, overall length, no. of imperfections (a chain is as strong as it's weakest link) plus whether they were multi-walled or single-walled, and chirality(affaects electrical conductivity).

Anyway i'll shut up now....

What you just said is over my head
but i will try to figure it out

[Kaptain K]

Then there is weather to worry about. All you need is one hurricane to destroy the whole thing.

A space elevator would have to be over the equator (The only place where a geosynchronus orbit is also geostationary.) Hurricanes are a temperate zone weather phenomenon. There are no hurricanes in the tropics.

[Argos]

On 2003-02-07 08:15, Kaptain K wrote:

Then there is weather to worry about. All you need is one hurricane to destroy the whole thing.

A space elevator would have to be over the equator (The only place where a geosynchronus orbit is also geostationary.) Hurricanes are a temperate zone weather phenomenon. There are no hurricanes in the tropics.

I don´t think a hurricane could threaten such a huge structure as the base of the space elevator.

Anyway, the whole idea lacks elegance. Space elevator would be a monster; an ecologist´s nightmare. It would always hurt some important bioma, regardless of where it were located (especially at the equator). It would degrade the landscape, since it could be seen from a vast area around. It would interfere with local [perhaps global] weather and other human affairs as transport, communications and so on. It has the potential for hindering people´s activities in a large scale. On the other hand the space elevator could be used to generate energy, as it drags across the magnetic field of Earth. This could balance (at least partially, by a small fraction) the environmental debt it would generate. The environmental impact [as well as the cost/benefit ratio] is something that will be carefully addressed in this question.

I would prefer something better to take us to the stars, although I´m not against the project by the wholesale. But I´m trying to point out its severe downsides.

<font size=-1>[ This Message was edited by: Argos on 2003-02-08 07:33 ]</font>

[Argos]

And from "Wired"

Edwards said a space elevator could transport materials into the cosmos for about $100 a kilogram. He estimated that sending materials on a shuttle costs $10,000 to $40,000 per kilogram. That could make it affordable, for example, to build huge solar-energy gatherers and send them into space on the elevator.

"African countries could send up a solar satellite, and use that energy to build wells, and pump water and develop their economies," Edwards said.

I don´t thing the environmental impact of sending a microwave beam down to Earth has been correctly adressed either,

[Eirik]

I'm not sure that this would be a huge problem. My understanding is that mircrowaves are pretty narrow and can be focused very tightly. A few large, high capacity solar panels might be able to generate a great deal more energy with less overall environmental effect than a large coal burning powerplant, for example.

On a flip side, I've heard of the proposal for large orbiting mirrors to focus light on specific points of the earth 24/7 for either energy production or greater growing seasons. Not sure how viable that is, either.

[logicboy]

[qoute]On a flip side, I've heard of the proposal for large orbiting mirrors to focus light on specific points of the earth 24/7 for either energy production or greater growing seasons. Not sure how viable that is, either.[/qoute]

Die Another Day?

I would think it would have to be a very big mirror + how much could it do for growing? unless the plants were genetically altered somehow to handle 24 hour sunlight. Light is like water to plants too much can kill.

[Eirik]

The concept existed before the doomsday weapon of that movie. I understood that a small scale test was done a few years ago, in which an orbiting mirror was used to shine sunlight on a small area of land. Beyond that, I've not heard anything about it.

And you're right, my understanding of plant biology is that there is a needed dark cycle as part of their growth cycle, but that you might improve yeilds by increasing the amount of time that they spend in spring and summer conditions, such as occurs naturally in places like California or central America.

[Eirik]

Did a quick search for information and this was the first site that I found, giving information on a failed Russian venture along these lines:

http://www.space-frontier.org/Events/Znamya/

[Argos]

I have on more thing on this matter.

During the evolution of space exploration, space industry was always regarded as a continuum to the aircraft industry. The space was an extension of the sky. With SE we’ll have to opt. Once the SE is built we can never send satellites to orbit by aerodynamic means anymore. Given the obstacle represented by the elevator tower, it will not be possible to orbit Earth bellow the altitude of the elevator. This will have an impact on astronautic science. SE will cause a cleavage in the aerospace industry. The synergy between aircraft and spacecraft will cease, or lose momentum, since we’ll go to the space by land! [Will the traditional Air Force influence in space issues slowly turn to the Army?].

The problem is that, as we’ll still need to work in other atmospheres elsewhere, we can’t afford to forget aerodynamics as applied to space vehicles. As result, we’ll have two technologies to deal with space affairs: the elevator to put satellites in Earth orbit, and the common aerospace vehicles to work elsewhere. This introduces a complication in our space system, and, therefore, a rise in the costs.

Also, during the construction of the tower all the low orbit satellites will have to be deorbited (And there’s a lot of them up there). All our needs will have to be satisfied by high orbit satellites, which imposes a considerable hike in costs.

There’s more to the project Space Elevator than meets the eye.

[darkhunter]

On 2003-02-08 07:32, Argos wrote:
I have on more thing on this matter.

Also, during the construction of the tower all the low orbit satellites will have to be deorbited (And there’s a lot of them up there). All our needs will have to be satisfied by high orbit satellites, which imposes a considerable hike in costs.

There’s more to the project Space Elevator than meets the eye.

Not to mention the utter loss of access to space should we decommision our launch platforms, the have some catastrophe that destroys the space elevator.

In todays world, I would hesitate to build one due to the fact it is a rather large target, and there will always be the chance some Bad Guy (Tm) decides it has to go...

edit: WOOHOO!!! not a newbie anymore....I'm an apprentice (though still got a ways to go...)
_________________
Words define reality, but they can't alter it.

<font size=-1>[ This Message was edited by: darkhunter on 2003-02-08 15:29 ]</font>

[g99]

On 2003-02-08 15:27, darkhunter wrote:

edit: WOOHOO!!! not a newbie anymore....I'm an apprentice (though still got a ways to go...)
_________________
Words define reality, but they can't alter it.

What a coincidence, i hit 1000 just a few minutes ago. Congradulations!!!!!!!. Just promise to make your posts alot more informative than mine are. [img]/phpBB/images/smiles/icon_smile.gif[/img]

And believe me it will not be long till you reach 1000. It will sneak up on you very fast.

[DaveC]

Congrats, g99. I'm looking forward to the day when I get there too, although at the rate I'm going I have a long road ahead.