Elevator to Orbit

in space-elevator •  8 years ago  (edited)

Elevator to Orbit

Once you are in low earth orbit, you’re halfway to anywhere in the Solar System. You can use the Interplanetary Transport Network to go anywhere, almost like falling down hill. In fact it would be exactly like falling down hill. Granted, it’s slow. Food, water, air, and other details will have to be worked out.


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The first step is the hard one.

The question is. How to get to orbit cheap enough? Rockets are out. It costs over then thousand dollars a pound to put something into orbit today. That means anything you put into orbit will have a cost greater than gold. That’s just right out. Can’t do that.

So we build an elevator.

We ALMOST have the technology. A company called Graphene Lab Inc. is working on part of it as we speak. There are others. The technological capability, she is progressing.
According to these guys (and others) The tech level will be a thousand times more advanced in ten years than what we have today. Yup..that ought to do it. So let’s project ahead a decade, assume the tech has matured, gotten cheaper, and we want to build an elevator to orbit.

Perhaps we’d do this.

Find a spot on the equator. MOST of the equator is ocean. Pick a spot on the ocean far, far, from any nation’s interest. Because crabs.


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Out of sight out of mind. If they we’re not ‘in-their-face’ they might not mind. (ha! They will and you know it. Governments say ‘no’ that’s what they do. So the elevator to orbit will have to be weaponized defensively I suggest lasers)

As I was saying. Pick a spot in the Pacific ocean far, far, from land. Then drop anchor. The deeper the better. Drop many anchors. Form a perimeter of ‘guy wire ships’ around a central point. The bigger the better. I suspect tens of miles radius would be optimal. (perhaps fifty?)

Drop the central anchor to the ocean floor and the fun begins. It’s NOT just an anchor. It’s a drill. It drill deep, deep into the ocean floor and spreads out like a flower petal once it gets deep enough. We want it to be anchored FIRM.

The material we are using for all of the construction is carbon. The raw material, probably from crude oil tanker ships, will be converted by our construction ship to structures made from graphene. The method of construction will be 3D printing.

Ok...we’re anchored firm. An Ocean Thermal Energy Converter has been constructed to convert the temperature differential between the ocean floor several miles below, (barely above freezing) and the hot water on the surface.

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Now the fun begins

Build a tethered aerostat. Not just any common, ordinary tethered ballonmind you either.



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Think BIG. Perhaps a mile in diameter. The envelope will be made from graphene.

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An acre of graphene only weighs a few ounces yet it’s stronger than steel AND impervious to hydrogen gas. The ocean is just sitting there...all that water. We have the POWER...from the OTEC. So we electrolyze the ocean water to produce Hydrogen, and Oxygen gas. Inflate the aerostat envelope with the hydrogen and store the Oxygen for later use. Oh yeah. Ocean water has a LOT of ‘impurities’ dissolved in it. Don’t think of the material as impurities. Think of them as windfall treasures. I mean they’re ‘just sitting there’ why not use them. Can’t let all that gold go to waste!

The aero-stat she begins to rise. Think large. A sphere with a mile radius, 5,280 (that would be 1.60934 kilometers) has a volume of 6.16581 x 10^11 cubic feet. (616,581,000,000 cubic feet). One cubic foot of hydrogen will lift sixty pounds. Fill the envelope with hydrogen and it will lift. (60 x 616,581,000,000 = 36,994,860,000,000 lbs. or (36,994,860,000,000/2,000= 18,497,430,000 tons.) Call it eighteen and a half giga-tons.

Tower.
Oops? Perhaps we should start with something smaller?

Naww...what the hell! Go for the GOLD. Build it TEXAS SIZE.

Ok...we have a potential of about eighteen giga-tons of lift to work with. But let’s be conservative. While the envelope is being printed by the graphene 3D printer fill it slowly with H2 with the electrolyzed hydrogen. Recall that the surface of a sphere a half mile in radius is 4πr2=4·π·26402≈8.75826×107, That would be 87,582,600 square feet. (87,582,600/2,000,788= 43.7740530231) square miles. Graphene weighs .77 milligrams per square meter, or .77 milligrams / 10.7630 (square feet in a square meter0 = .0715413818 milligrams a square foot.

Not very heavy is it?

The whole envelope would weigh ( .0715413818 x 87,582,600 =6265780.22564 milligrams) or 6265.78022564 grams or 6.265 kilograms or about three pounds.

Huh? Can that be right? A sphere with a diameter of a mile, made from graphene would weigh about the same as your average cantaloupe?

I might have dropped a decimal point somewhere, check my math if you feel the urge. Irregardless. Anything made from graphene is LIGHT. Graphene is also STRONG. It has a tensile strength of 130 gigapascals. A36 Structural steel has a structural strength of .4 gigapascals. (130,000,000,000 /400,000,000= 325) Graphene is 325 times stronger than steel. It’s also hydrogen gas proof. It won’t leak. Possibly the only material found for which that can be said.

SO...what we have here is a potential net lift of about eighteen billion tons.

So let’s do that. Continue to run the 3D printer, printing the structure, and filling the hydrogen envelope as needed so that it lifts straight up. Remember the guy wire ships in the fifty mile(or something) radius? They’ve been busy too. They done something similar only less complex. Their job is to anchors the aerostat as it goes up. They sunk anchors and use the same type of tech to produce thousands of miles of bucky-tube cable. The cable is attached to the rising aerostat and reeled out slowly as it ascends.

From a distance it would look like Jack In the Bean Stalk’s BeanStalk Growing.

Ok...let’s be conservative. All the fiddly bits hanging down from the aero stat, much like tentacles below a jellyfish, weigh something. SURE we have eighteen billion tons of lift to play with. But let’s build in an ‘oh-shit’ factor. Let’s only use a billion tons at a time...just in case.

Ok...so let’s suppose, taking future additions and expansions into consideration, that we decide to build a ‘bead’ on the ‘string’ every ‘x’ distance . The Aerostat would lift x-distance then the 3D printer wold make ANOTHER ‘bead’ with ANOTHER 18 gigatons of lift. No pain and no strain until the top of the atmosphere is reached. By this time a number of tanker ship loads of crude oil have been converted to graphene, bucky balls, and other stuff. Quite a complex has grown.

However, a hydrogen ballon can only lift so high. The record right now is 32 miles. Not NEAR high enough. So...we have all of that hydrogen and oxygen just sitting there.

Rocket fuel!

Mix H2 + O and you get high temp steam. Due to the design we have an unlimited amount. Anticipating this happy event. Hundreds if not thousands of steam rockets have been built into the lower perimeter of the structure of each bead. When, say, a thirty mile altitude is reached.

STEAM ON!

Rocket power , Similar to water jets

but steam

It never runs out of steam and continues to lift the whole beanstalk straight up.

Remember it is steadied by many, many, guy lines which are anchored the sea floor. Good thing too cause it’s gonna need it. It has a long ways to go to geosych orbit . 22,236 miles (35,786 kilometers) to be more precise. This might take a while.

Eventually it will get there. The energy needed is HUGE, but the OTEC can supply infinite energy. As long as the CrudeOil Tankers keep delivering their cargo it will go up...up...and...UP.

BONUS!!

When it reaches Geosynch (or before) it lifts itself. It no longer NEEDS the steam rockets. BUT....it might be a good idea to use them anyway...to manage ‘strain’. We I mean...buckytubes are only 325 times stronger than steel. Wouldn’t want to stress it any.

So now we have this....

That allows us to build THIS.

STEEM ON!!

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Very clever writeup.
Geosync altitude is 26,199 miles or about 6.5 earth radii. So, to scale, your tower would need to be a bit higher with guy wires spread out over many oceans.

why would the guy wire need to extend above the atmosphere?

  ·  8 years ago (edited)

I'm no mechanical engineer, but I can imagine all kind of undamped vibrations getting out of control.
Then there are diurnal cycle considerations: variations in heat loading, solar winds, uneven stresses from conservation of angular momentum while using the elevator to move a mass vertically (the ice skater spin acceleration effect). Even lunar tides and the variations in gravity due to continental land mass and non-uniform gravity vectors from the earth's pear shape. These already cause station keeping issues with geosync satellites. There are only 2 points in the geosync orbital ring where forces balance out. You can imagine how valuable that real estate is.

That's a long lever arm and a small force can generate some serious torque.

So cool. I hope you're right :)

I think it would be awesome, hope you are right.

Addendum:
After giving this some more thought it strikes me that a space elevator is scaleable. It could very very small (skinny, not short...length is constrained due to physics) perhaps VERY much so. Think 'micro-satellite' launcher.