[Grey Wolf]

Originally posted by ShadowWolf_IH
the one i find fascinating rictor...is roads.....think about what we have done with paved roads in the last 100 years.  that's of road for only 100 years, and to think they did it all with 3 supervisors watching 1 guy work.

and now we go to 20 years ago...when one of the IBM big wigs asked why anyone would want a computer in thier home.....

now let's see some real scary progress....remember the furby?  that child's toy had more raw computing power than the lunar lander did.  My god, we left a furby in charge of getting our men to the moon and back.

Not twenty years ago. Has to be at least 30, as IBM sold PCs since the early 1980s.

[Osiri]

who cares about the past live for the future.

Think about this.  50 years ago no one had been in space.  There was no country with the capability of space flight.  Now we are bored with the moon.

Also 20 years ago string theory, much less M-Theory were disregarded as fantasy.  Now multiverse is a powerful school of thought.  Gravity is even being attributed to a leak from our universe to another of this force.

Science is the ultimate advancement.  

When we either create a pocket universe that separates from our own in a microsecond(but is detected) or we someone learn to measure higher dimensional interactions, I think the world will finally take note of science.

Finally, he who builds the first space elevator will rule the earth and the universe.  He will be able to put up the next space elevator for 1/100th the cost of the first.  That is the ultimate advantage.  

The US and EU need to make it before China[ or Korea]. EDIT KOREA!!!! THAT WAS A WOOPSIE

[aldo_14]

Korea?!

What, as in critically impoverished, people dying in the streets of starvation, famine struck North Korea?

[Grey Wolf]

Without understanding the past, then you have virtually no chance of advancing.

And as for being "bored with the moon", that's a blatant lie. Funding was cut, and the remains were diverted to the shuttle, which, while an interesting concept, was actually a step backward.

And an orbital elevator is flawed, at least any we could build now. Namely, we lack any material strong enough to do it. We have some that could do it, but aren't stable (mettalic hydrogen, for example). As for building it, you know they can only be built at the equator, right?

[Osiri]

Come on man I am joking.  We are not scientifically bored with the moon.
Politically we are.  

Elevators: They can be built in the ocean.  International waters.  Any country can do it.  Any major power could defend it.

Materials:  We should pour research into it.  The truth is once it was built it would be cheaper than using any other means to get to space.  
We are not as far as you think from having carbon nanotubes capable of doing this.
The thing is it is not that hard we should just get off our collective asses and show some support for it.  
Further, the materials needed would have an unbelievable number other uses.

[Grey Wolf]

Developing entirely new materials is not easy. And carbon nanotubes are incredibly hard to make in a decent size.

[Osiri]

Now but we need to fund the hell out of it.  

We don't do that right now.

[Janos]

Originally posted by Osiri
Come on man I am joking.  We are not scientifically bored with the moon.
Politically we are.  

Elevators: They can be built in the ocean.  International waters.  Any country can do it.  Any major power could defend it.

Materials:  We should pour research into it.  The truth is once it was built it would be cheaper than using any other means to get to space.  
We are not as far as you think from having carbon nanotubes capable of doing this.
The thing is it is not that hard we should just get off our collective asses and show some support for it.  
Further, the materials needed would have an unbelievable number other uses.

Some weird defence contractor guy on Somethingawful forums crushed our party with cold maths:
Steel, bricks and spider silk won't work- they would all literally snap and collapse under their own weight. Which is why a theoretical material 2 orders of magnitude stronger & lighter than the strongest carbon nanotube string ever tested is required. It's not that steel would be too large or expensive, it quite simply is too heavy and not strong enough to work EVER. But don't worry, we'll still tap the world's steel deposits dry building the 2-mile high anchor station required to support the space elevator. See, it has a real problem with vibrations, and the anchor at the ground will require the ability to move up and down 2 miles to maintain the proper tension, lest the space elevator become overstressed and snap. (They didn't mention that part in popular mechanics, did they?)

The space elevator doesn't look like the photos you've seen. It doesn't look like an elevator. The envisioned space elevator capable of lifting the same cargo as the space shuttle is about the width of a shoelace but paper thin while going through earth's atmosphere. It's tiny; it has the cross-section of a human hair. It has to because it requires a taper and to make it thicker here would require a likewise thickening in space and it becomes technically even less feasible. So, basically, you're looking at the world's tallest lightning rod that's about as large as a piece of fishing line.

Now, we all know carbon nanotubes are a conductor, but they're unfortunately a fairly poor conductor (10-4Ohm-m), about 50kOhm overall. A 400,000V bolt of lightning will be pumping the space elevator (with the cross section of a piece of fishing line) with about 3 million watts of power. Meaning that when it does get hit by lightning, it will instantly explode. Even just a small % damage will cause it to overstress and snap. Running a conductor along it is too heavy; cabling that heavy will literally weigh in the tons, which effectively means the space elevator would have no capacity for cargo. Wrapping it in a giant 10-mile high conductive tower (or anchoring it at the top of the tower) is about the only way you're going to protect it. Considering they want [need] a mobile (floating) platform so they can move the elevator out of the way or orbital debris and other hazards, this is potentially a show-stopper right here.

And some other jerk further ruined the "well what about STRONGER than carbon nanotubes HUH?!?!?!!" counter-argument:
what we know of physics is in full support that carbon nanotubes are bordering the strongest material possible. This is because they have the strongest bonding structure of any molecular/atomic structure currently supported by any and all laws of physics/chemistry that produces an actual material. In other words, to create a stronger structure that could replace the nanotubes, you would have to violate the entirety of known physics, or you have a monomolecular whip that would destroy anything it touches.

I hate maths, they crush my dreams of joy, liberation and philosophical enlightment. And pudding.

GOD DAMN PUDDING CRUSHERS

[Osiri]

I forget the fixes to this problem that have been suggested.

Once you get a single line run multiple others could be run.  If they are all capable of supporting thier own weight plus some more weight then theoretically the more you run the better.  

EDIT: see the article below... I should have said ribbon. Disregard cable and read ribbon each time.  Thats what it is.

Just because a cable weighs more than a single fiber of the cable does not mean that it is weaker.  Else there would be no use in making cables.  I haven't looked into the physics of this paragraph but from a common sense view consider.

1 strand capable of supporting its own weight plus 50 lbs.

run 1000 more strands and yes you have 1000 times the weight but now you have 1000 times the tensile strength and it can support 50000 lb load.

I am sure there is some loss of strength in this so reduce the support by half.  now 25000 lbs on the tensile.  

Now run 5 more cables of equal strength.  or 50 for all I care.  

I am sure this is hair brained or something but could someone tell me why.

Now heres a fun thought.  Consider his argument.  If the cable snapped think about a fishing line stronger than steel flying through the air at 100s of miles an hour.  

If it came down through a city I wonder if the tensile strength would allow it to cut through buildings.

The cable could not stop because it would be being pulled by literally tons of material on the other side of the building.

anyhow that would be hilariously horrifying.

[Osiri]

Here.  This is a quote from space.com

http://www.space.com/businesstechnology/technology/space_elevator_020327-2.html

__________________________________________________
Getting the first space elevator off the ground, factually, would use two space shuttle flights. Twenty tons of cable and reel would be kicked up to geosynchronous altitude by an upper stage motor. The cable is then snaked to Earth and attached to an ocean-based anchor station, situated within the equatorial Pacific. That platform would be similar to the structure used for the Sea Launch expendable rocket program.

Once secure, a platform-based free-electron laser system is used to beam energy to photocell-laden "climbers". These are automated devices that ride the initial ribbon skyward. Each climber adds more and more ribbon to the first, thereby increasing the cable's overall strength. Some two-and-a-half years later, and using nearly 300 climbers, a first space elevator capable of supporting over 20-tons (20,000-kilograms) is ready for service.

"If budget estimates are correct, we could do it for under $10 billion. The first cable could launch multi-ton payloads every 3 days. Cargo hoisted by laser-powered climbers, be it fragile payloads such as radio dishes, complex planetary probes, solar power satellites, or human-carrying modules could be dropped off in geosynchronous orbit in a week's travel time," Edwards said.

Using a laser beam to boost the climbers into space is doable, said Harold Bennett, president of Bennett Optical Research, Inc. of Ridgecrest, California. "If you do it right, you can take out 96 percent of the effect of the atmosphere on the laser beam through adaptive optics," he said. The strength of the pulsed laser beam is less than the intensity of the Sun, so birds, airplanes, or human eyes wouldn't be affected, he said.
___________________________________________________


The projected cost is less than 10 billion.  We are spending over 100 billion right now to return to the moon by 2018.

10 Billion is well within the abilities of Bill Gates, the Waltons, and hundreds of other individuals much less corporations.

[aldo_14]

I believe the best plan is of a hexagonal structure using 6 cables, with double redundancy.  Albeit that wouldn't solve other problems like falling ice on high-alititude parts or space debris impacts (particularly in terms of defending against that without also breaching treaties on space weapons)

I'm not sure whether you'd have even as much as 1/2 the combined weight support, though; I think that might depend a lot on the likes of weight distribution for one thing.  I think a proper cable would have to be structured in the normal way of wrapped strands (IIRC this is for additional strength through weight distribution), so I doubt you could just start by raising a single strand.

The obvious issue is surely the tremendous difficulty of building and raising that amount of cable, I'd imagine.  You'd likely need further research into a heavy lift capability anyways.  Personally, I think a space elevator is a pipe dream in purely political - let alone technical - terms; I'd rather see more work on efficient spacecraft and new propulsion methods.  After all, a space elevator can only take us so far on it's own (and yeah, I understand it's value in that context in terms of it providing a neat launch platform).

[Osiri]

20 tons is the projected weight of the entire first cable


and sorry.  I will update the earlier post to say ribbon as it should

Also someone has tested a climber let me finish reading the article real quick


Lift Port Group is the entity I am refering to

Holy **** are these guys for real.

They are actually a company trying to do it

Lift Port Group

and check out their faq and news

[aldo_14]

Interesting. (er, not related to LiftPort.  I'm not sure exactly how realistic the prospects are of a non-governmental space elevator)

Apparently, carbon nanotubes cost from 20 to (for what I presume is strongest) up to 1000 euros per gram in 2003.

So... by a very rough and assumptive calculation.
20,000,000,000 euros for the first cable.  Which is about $23.9bn for the material alone; I'm not sure if there are any fabrication plants that can produce that amount of nanotube cable, and there's obviously the cost of research, testing, building the ground and space stations, and of course making the lifters.

I'm not sure how they're estimating $10bn, to be honest.

[Osiri]

They are building thier own manufacturing plant and it is becoming cheaper to produce them

Further who cares.

10 billion
20 billion
50 billion

once the first is up the others come at fractions of the price

you could have 10 of them for less than the cost of returning to the moon on rocket power.

BTW
if you were to go out on the counterweight

your angular momentum would be enough to launch you to the moon.

That is also included in the two websites I posted

also 20 tons is not that much weight when you think about it

The cable is 1000s of miles long

I was thinking the cable would be in the 100s of tons.

OH ya the spent climbers(the robots that reinforce the ribbon with more ribbon) become your counterweight.

you need the counterweight to keep it from becoming loose or from tiliting


also aldo, one thing you should realize is that the government of the US would instantly protect the space elevator once it became clear that a US company was going to really get it built.  

This is because that company would give the government lower costs on using the space elevator.

[aldo_14]

[q]
also aldo, one thing you should realize is that the government of the US would instantly protect the space elevator once it became clear that a US company was going to really get it built. [/q]

That's sort of my point.  There's really an inherent issue in terms of not just security, but control.  Would an SE be built on US territory or cheaper foreign territory (it's not stated where they - LiftGroup - plan to build this; only offshore in the pacific), for example. If it was the latter, would the US government be willing to allow the construction of it, unless they had discretionary control over who uses it, and soforth.  To me there'd be a whole raft of legal and jurisdictional issues that could be a problem.

I doubt the US government would be particularly happy to pick up the tab of protecting a private SE, in any case.  I guess that'd be another (significant) cost.

(I think there's potential for a 20-year, largely theoretical, plan with such a vast scope to become more of a cash sink than an actual viable company)

So I think it's more feasible to see this sort of thing by government than private industry, simply because of the red tape involved and the nature of it.  Plus I have to admit a slight nervousness at the concept of such a thing being privately owned, potentially with minimal oversight.

Oh, and in terms of heavy lift; I was more thinking of Mars, and beyond type travel (not necessarily human, of course).  I'm not sure, even with a space based launch platform, we have the right technology to do that well (namely quickly and efficiently).  That's what I mean; is it better in terms of solar system scale exploration to spend billions developing a space based launch platform, or to spend that upon, say, ion drive experimentation.  I'm not sure it's the former.

[Osiri]

they stated in the pacific ocean 700 miles from air traffic flight paths

Read the article.

A launch from the counterweight would actually have the momentum to get you to Mars, Venus or the Asteroids.

I didn't see anything about Jupiter so I guess that is a bit beyond this momentum.

All at $250 a lb.  

That is amazingly cheap to get to Mars.

Getting back would be more difficult I assume.

The US would certainly oversight it.

[Osiri]

It does not matter that liftport will go under

what matters is that the research and manufacturing capabilities are actually being established.

Liftport goes under someone else take over gives it the needed influx of cash and boom it is fully privately funded.

And that new owner controls the world.
well at least until someone else puts another up.

but by then the original owner has strung 4 more and the costs are miniscule and who is going to use the much more expensive elevators of a newcomer.

That is why the first builder will control.

[aldo_14]

Originally posted by Osiri
they stated in the pacific ocean

Read the article.[/QUOTE

Did you read my reply atall?  I know they said in the Pacific Ocean, but the Pacific is not solely US territory.  Like most oceans, it's actually rather large.

Originally posted by Osiri

A launch from the counterweight would actually have the momentum to get you to Mars, Venus or the Asteroids.

I didn't see anything about Jupiter so I guess that is a bit beyond this momentum.

I'm not sure I get you.  Are we talking about using the space-elevator as an accelerator and just 'letting go' at the top?  Or getting to the top, and then launching from there?

I've not read anything to suggest that an elevator launched interplanetary mission could omit engines.  Reduce the heavy lifting requirements, yes, but not remove the need for propulsion altogether.

SELF-CORRECTION; apparently with a postulated 144,000 km cable it'd be possible to reach an exit velocity high enough to send probes to Saturn.  I'm not sure about the vagarities of actually steering the thing

Originally posted by Osiri
All at $250 a lb.  

That is amazingly cheap to get to Mars.

Getting back would be more difficult I assume.

Back is pretty minor; I don't think there's any point in sending manned expeditions at present, we'll learn as much with robots and without the logistical barriers of food, oxygen, etc.

Originally posted by Osiri
The US would certainly oversight it.

 I'm not sure there is a barrier on US companies relocating their centre of operations, and if they were to shove the actual platform in international waters or non-US soil, you could be looking at some major probs there.   Something like a space elevator, I'd rather have complete governmental control with UN oversight to it.

(actually, I wonder how much the likes of NASA would use such a thing, if they couldn't guarantee total control over it; is there a stated policy, US or otherwise, on the rights of individuals or companies to develop space travel or technology?  I know the US army is actively working on ways to deny hostile nations use of neutral space technology (http://www.army.mil/professionalwriting/volumes/volume2/june_2004/6_04_4.html))

Incidentally, what are the practicalities of manufacturing a 144,000 km long graphite cable?  I've read that you need to bond carbon nanotubes with a soft composite (i.e. graphite was the example cited) to form the length and type of ribbons needed.

Don't get me wrong, I'm not saying this is impossible - although I don;t think we're at the technical level yet to build it right now - I'm just not sure such a project is feasible for a private company given the likely international political issues, and the likely huge cost (nanotubes cost more per gram than gold).

I think it's more feasible to be by government; and I think at present it's more valuable to research new cheap propulsion technology (such as on a space shuttle replacement, probes, etc) and expand exploration than direct all this to a space elevator.  Unfortunately, what is being done - namely the moon landings plan - is to me just reusing old technology (principles) and isn't actually advancing anything.  So I'm not against it per se, I just don't think a space elevator is the most appropriate option for the moment.

Now, how did we get onto this from cellphones?

[Osiri]

First, it must be built in the ocean.  This avoids major concerns such as accidents, terrorist attacks, weather(weird but they say so), and I think the base station must be moblie  to account for slight drifts.

The US would oversight to the extent of protecting it and probably making sure that no one tried to use it for bad things.  

No US corp is willing to challenge the US government in a matter like this.  They would lose in an instant.  Further, the added benefit of government protection would be too hard to resist.

The owners would likely allow the US government to build its own elevator using the private one to get the materials into space.  

I agree that I would prefer the US government build the damn thing but the administration is too busy making plans for things they will never have to come through on.  

Another thing I want to point out is that right now we are spending huge amounts of money on shuttle take offs and landings(or were spending).  

The honest truth is that you could get a mission to Saturn as you say for $250 per lb or $550 per kg.  It would make multiple missions that are infeasible now completely feasible.  Even if it wouldn't get you to the Kupier Belt it might give you enough momentum that your convential rockets could get you out there.

Another idea is that you can put another space elevator on Mars and when you get to Mars you can again use the angular momentum of Mars to send you to another staging point.  

The problem becomes how would you get more push after Mars.

I wonder what the feasibility of lower a elevator cable from high Jupiter orbit into the gravity well beneath while at the same time extending the counter weight further away from Jupiter.

If the effective gravity pull on the lower counterweight were enough to balance the outward pull of the higher counterweight, it would still theoretically be a way to get into much higher orbit where you are actually outside of Jupiter's major grav well.(where you are moving so fast you would normally be shot off into space anyhow)  

This would be amazingly helpful because the speeds would far exceed the speed in orbit of earth.  

Although there is then a problem of too much tension causing the line to snap.

Back to the topic though...

This would be by far the cheapest method of propulsion ever suggested.

No expensive fuels.  No bombs.  No complex parts.  Just good old momentum.

It would be far safer.  Also steering would not be as bad as you think.
Directing explosive heat out of a rocket nozzle at a certain angle pressure and etc is much harder than timing a release based on pure tragectory.

further no one ever said that the things launched from these platforms could not have engines.

IDEA.

It would be cool to have multiple space elevators launch several components simultaneously that could assemble using small amounts of force to change trajectories.

Engine here fuel there and there and there and there.
For manned missions, food there there there there there.
Crew quarters.

Since they are not moving relative to each other slight amounts of force would allow them to be moved together and using good manuvering that is currently available(the International space station is assembled like this.

You could assemble the ship after launching it at the correct momentum.

Thereby allowing you to get over the 20 ton capacity for one ship


You would thereby not need the lunar base to launch major space flights.

IMO though you would want to launch interstellar or such from mars not from earth.  it would allow you to get up more velocity as you fly inward to the sun allowing you to actually reach the suns escape velocity.

You could also then use the nuclear bomb concept for propulsion


Finally, the practicalities of making a 144000 km ribbon is not as hard as you would think.  If you had the funding and a manufacturing plant it would not at all be difficult.

Yes we need a little more advancment in the fibers for it to work but not very much

[aldo_14]

I'm not denying the lauch savings of the space elevator, just the vast expenditure to build the thing.  I'm not sure that's justifiable at the moment if the technology isn't yet fully proven or discovered (this is not me ruling it out for investigation, just as being the primary/sole area of funding), particularly if (purely from a governmental funding point of view) space travel is still very far down on the list of priorities.

Whether or not LiftGroup go bust (and whether another company would be willing to step in), I would still say I'm not especially comfortable with this in the hands of a private organization.  I'd rather there to be some sort of altruistic motive, of course, although I guess no country would do this sort of thing 'for the good of humanity'.  Might be nice to have that pretence, though.

But I think terrorist attacks, and more likely accidents, are still possible in an ocean mounted cable.  Accidents on the ground would be possible as this sort of thing would have to be a major cargo hub to be viable, and in space from the obvious - debris & satellites.

In terms of US oversight.... I honestly don't know what the legal, jurisdictional and economic range of that is.   Like... how much responsibility would the US take for ensuring the cable is properly maintained and no costs are cut.  Or what sort of right the Us would have to veto contracts from, say, Chinese companies or government.  I think it's a very muddy issue there.

Or a stupid question that occurred to me; what would happen if the owners of the cable, once built, went bust? Would they take it down?  Would (a) government take over?   Just curious.

EDIT;
[q]
You could also then use the nuclear bomb concept for propulsion[/q]

I don't think that's legal under UN treaties over weaponization of space.  Plus a lot of countries would go ape**** over it .

It's a shame, because Project Orion (in the 50s) was an interesting theory for interstellar (albeit very slow in human terms) interstellar travel.