The unsolved engineering of the "Space Ladder"

[Lorzazu]

Spent several hours reading about the approaches and methodology of engineering the conceptual idea of a space ladder. I had no idea it was such a relevant project still.
I had a few thoughts on it though:
1. In every proposal it seems the objective was to build a "connect a here to b up there" system.
-I feel that it's the wrong approach. I believe the "barrel full of monkeys" approach is better.
2. Tons of thought by very smart people on solving the material of the "cable" and engineering behind essentially overcoming the ability of the cable to maintain the stress of its own weight.
-Why fight gravity and atmosphere? Instead envision a helium/hydrogen line that supports its own weight but also supplies hydrogen to a "hot air ballon" type stage 1, that transports the "climber" to a atmospheric platform suspended by helium (obviously requiring a piloting mechanism is needed). From there, at "stage 2", the hot air balloon craft could deploy back.
3. At first, yes. A lot of hydrogen/helium gas may need to be used in constructing "stage 2 and stage 3" together. Stage 2, the atmospheric platform would then need to be joined to a space orbiting structure/craft.
4. Now this portion of the connection would have to be along the lines of carbon nanotubes, however we have eliminated 60 to 80 miles of cable material length needed which = a lot less weight.
5. 60-80 miles does not put you in a geo synchronized orbit. Perhaps this device may need to be assisted either by a type of propulsion fuel at the beginning to resist re-entry, but what about a concept of having the device fixed with a repulsion element that would "like a magnetic force" push itself away from Earth's gravity?
6. Last, this device would be able to tether to a station in a stable orbit. Then the station would also have to be counterbalanced to another focal point to counteract centrifugal forces.

Any ideas?

 

[phyzguy]

Synchronized orbit is 25,000 miles up. Eliminating 60-80 miles of it isn't much help.

 

[phinds]

what about a concept of having the device fixed with a repulsion element that would "like a magnetic force" push itself away from Earth's gravity?

Are you saying that you believe in anti-gravity?

 

[Lorzazu]

Are you saying that you believe in anti-gravity?

I do believe in oppositional magnetic force...besides.. 20 years from now when you figure out anti gravity we won't worry about it.

 

[Asymptotic]

A lot of hydrogen/helium gas may need to be used in constructing "stage 2 and stage 3" together. Stage 2, the atmospheric platform would then need to be joined to a space orbiting structure/craft.
4. Now this portion of the connection would have to be along the lines of carbon nanotubes, however we have eliminated 60 to 80 miles of cable material length needed which = a lot less weight.

60-80 miles does not put you in a geo synchronized orbit.

What about the distance between the stage 2 atmospheric platform and the 60 to 80 mile mark? The altitude record for a helium balloon is 53 km, or about 33 miles.

 

[Lorzazu]

What about the distance between the stage 2 atmospheric platform and the 60 to 80 mile mark? The altitude record for a helium balloon is 53 km, or about 33 miles.

Good point. I know that some of the atmospheric balloons that get sent up for example to get images of the Earth at high altitude will be affected by the conditions of the upper troposphere. For this purpose though, the typical balloon type system wouldn't be very useful.

Is it conceivable to create a high atmospheric platform?

 

[anorlunda]

I do believe in oppositional magnetic force...besides.. 20 years from now when you figure out anti gravity we won't worry about it.

You should read the PF guidelines. We don't allow:

• Personal theories or speculations that go beyond or counter to generally-accepted science

That leaves plenty of room to debate space elevators within the rules.

 

[Lorzazu]

I humbly mistook this site as a forum for open thinking and I do believe it is more geared towards academia. I apologize.

 

[phyzguy]

I humbly mistook this site as a forum for open thinking and I do believe it is more geared towards academia. I apologize.

Perhaps it will help you learn the difference between open thinking and fantasy.

 

[phinds]

I humbly mistook this site as a forum for open thinking and I do believe it is more geared towards academia. I apologize.

Thinking outside the box is an admirable activity, BUT ... first you have to learn what's IN the box.

 

[anorlunda]

Thinking outside the box is an admirable activity, BUT ... first you have to learn what's IN the box.

Make that a bit shorter and we would have another great PF tee shirt.

 

[gary350]

Easy way to get into outer space, build a ramp so you can drive your car. Put a Cul-de-sac at the top to turn around and drive back. When the space station comes around get out of your car and take a ride on the space station. Car with magnetic tires needs to be fueled by nitrous oxide. You can even base jump and bungee jump from the ramp.

 

[Lorzazu]

so...thats what you have IN the box? A giant cul-de-sac ramp? How about stacking up all of the garbage and waste the entire human race disposes of into one giant pile. Wouldn't be surprised if it grew large enough to reach space. Not really a fantasy either, rather a brutal reality.

 

[phyzguy]

so...thats what you have IN the box? A giant cul-de-sac ramp? How about stacking up all of the garbage and waste the entire human race disposes of into one giant pile. Wouldn't be surprised if it grew large enough to reach space. Not really a fantasy either, rather a brutal reality.

Well, gary350's proposal is also fantasy. How could you build a ramp over 5000 miles long?

Easy way to get into outer space, build a ramp so you can drive your car. Put a Cul-de-sac at the top to turn around and drive back. When the space station comes around get out of your car and take a ride on the space station. Car with magnetic tires needs to be fueled by nitrous oxide. You can even base jump and bungee jump from the ramp.

You realize that even if you could build such a thing, that when "the space station comes around", it will go by at roughly 18,000 miles per hour? Do you propose to just grab on?

 

[rbelli1]

You realize that even if you could build such a thing, that when "the space station comes around", it will go by at roughly 18,000 miles per hour? Do you propose to just grab on?

Getting up there is the easy part. Going fast enough so that you miss the Earth when you fall back down takes quite a bit more effort. At least at space station orbital altitude.

BoB

 

[Lorzazu]

gary350 was not proposing anything except being sarcastic. Having said that...i thought it was funny and to be honest if there is one equation in this universe that really needs solving it's trying to maintain some levity and nonsensical humor in this world

 

[ThaSatelliteGuy]

Well, gary350's proposal is also fantasy. How could you build a ramp over 5000 miles long?
You realize that even if you could build such a thing, that when "the space station comes around", it will go by at roughly 18,000 miles per hour? Do you propose to just grab on?

OK, but for the sake of argument, if the ramp was 5000 miles long, would it not "stick out" into space quite far? I would think this would give the end of the ramp a much higher "tip speed", and therefor, the question would not be how fast is the space station moving, but rather the differential between the two moving points... My understanding of the space elevator concept is that this is what would generate the centrifugal force that is supposed to hold the whole thing up in the first place...

 

[Nik_2213]

Don't forget the space elevator needs a massive counter-weight on the far end to keep it taut...

 

[rbelli1]

if the ramp was 5000 miles long, would it not "stick out" into space quite far?

Yes. That is not very far as space is concerned.

My understanding of the space elevator concept is that this is what would generate the centrifugal force that is supposed to hold the whole thing up in the first place...

Yes. A space elevator needs to stick out "far" to actually work. 22K+ miles to be inexact.

BoB

 

[yahastu]

I like the idea of using helium to counteract the force of gravity. Unfortunately, as noted by Asymptotic, this would only be useful for the first 33 miles.

If you used an even lighter gas, you could go higher. What about using "vacuum" filled balloons instead?

Imagine the elevator is a tubular lattice, then place a vacuum filled ball at the bottom. It will propel itself all the way through the lattice, until the point where its total density (mass of container divided by volume) is met. If it's a sufficiently large container, this could propel itself to an arbitrary altitude. Actually, it could go further than that, due to momentum that it builds up.

The lattice structure could be designed with some friction so that these vacuum filled balls created an upward pressure on the structure itself, thereby counteracting the force of gravity and meaning that the lattice structure does not have to support it's own weight.

As long as you keep inserting new vacuum filled balls in at the bottom, this pressure could be maintained.

Alternatively, if you could place a series of sufficiently low mass downward thrusters along the length of the elevator, then the material wouldn't need to support all of it's own weight. For example, if Bohmian mechanics turns out to be a more accurate model than the standard Copenhagen interpretation, as seems increasingly likely from recent research (eg, http://advances.sciencemag.org/content/2/2/e1501466.full ), then the EM-drive's "reactionless thruster" can simply be explained by Bohmian mechanics ([URL='http://www.ikpress.org/abstract/6485']http://www.ikpress.org/abstract/6485), and could be placed at intervals along the elevator's length.[/URL]

 

[phinds]

What about using "vacuum" filled balloons instead?

And what would you make them out of that would be strong enough to not collapse but lighter than helium ?

 

[yahastu]

And what would you make them out of that would be strong enough to not collapse but lighter than helium ?

I'm not a structural engineer, but based on the below article, it seems that aluminum alloy spheres would be strong enough at sea level:
https://en.wikipedia.org/wiki/Vacuum_airship

However, the required strength of the ball would be much less if you made and inserted them into the elevator at a higher altitude where the air pressure was less. So, for example, you could build a helium platform at the maximum height your helium balloons would go to...which isn't much in terms of the total distance you need to go, but is a huge reduction in air density, allowing you to use significantly lighter weight material for your vacuum filled balls to go the rest of the way.

 

[deckart]

If you used an even lighter gas, you could go higher. What about using "vacuum" filled balloons instead?

I like this idea but I wouldn't call them "vacuum" filled or "balloons". It's hard to fill something with nothing and balloons only expand when filled with something. :)

 

[jbriggs444]

And what would you make them out of that would be strong enough to not collapse but lighter than helium ?

For style points, use lead.

 

[phinds]

However, the required strength of the ball would be much less if you made and inserted them into the elevator at a higher altitude where the air pressure was less. So, for example, you could build a helium platform at the maximum height your helium balloons would go to...which isn't much in terms of the total distance you need to go, but is a huge reduction in air density, allowing you to use significantly lighter weight material for your vacuum filled balls to go the rest of the way.

And then you need a production facility 30 miles up. I think the whole "vacuum balloon" thing is a non-starter.

 

[Nik_2213]

Yahastu, the problem with a vacuum 'airship' is you must put the skin over a huge frame capable of withstanding the inward pressure. This is seriously non-trivial. As a bare 'geodesic' or 'buckyball' shape would be very vulnerable to buckling and catastrophic collapse, you'd need a lot of internal bracing, probably by a tensegrity structure. see https://en.wikipedia.org/wiki/Tensegrity

Hmm: Also check out... https://en.wikipedia.org/wiki/Aerogel

Remember, your 'space ladder' just has to be very, very strong in tension, but your vacuum balloons' construction must be as strong in compression, too. Yet, every gram of structure comes off your pay-load and, if 'crew-rated', safety margins add to your woes. As it stands, you need a truck-load of 'Unobtanium' just to break-even...

There are other ways to make a space-ladder stand up; IIRC, the British Interplanetary Society (BIS) published a lot of peer-reviewed material on 'dynamic' compression structures, eg with a ground-fixed coil-gun and sections of space-ladder etc magnetically 'bleeding' momentum from the 'smart' projectile stream. Think BIG, CLEVER engineering, rather than 'Magic'...