Orbital Rings Within The Atmosphere.

[Pds314]

I just thought of something. wouldn't it be possible to make something that moves partially at greater than orbital speed and partially at stationary speed relative to the surface in order to balance it out into an orbital ring?

It works as follows: You make a flexible bridge around the world with a particle accelerator in it. You start it with, say, 60 km of slack bent out so that you don't have to build it in mid-air.

Then you put something like a particle accelerator inside it to generate lift.

So for example, if one had a ring with a mass of 100 tonnes per meter (about 4,000,000,000 tonnes overall) and used a particle beam inside that weighed 25 tonnes overall to 1/3rd the speed of light, one could generate enough force to lift the entire bridge via orbital left on the particle accelerator.

The centripetal force is proportional to the velocity squared times the mass, whereas the momentum is proportional to the velocity times the mass. This means that you only need to put the beam in at a certain energy, and the less it weighs, the better. Thus, despite being able to hover in mid-air, much as though it were in orbit, the bridge would not be kicked back at orbital speed. This is because beams of absurdly fast particles have a very high specific impulse. (the bridge would recoil at just 0.625 m/s from accelerating the beam to that particular speed).

Thus, we could have a world-spanning bridge just sitting around at jet-liner altitudes being held up by a particle accelerator and nothing else at no energy cost.

It could also be moved, accelerated, landed, etc under fairly minimal power.

And it could be set to any orbital altitude, or shape. An Elliptical bridge allowing one to walk from the ground to LEO would be completely possible without making it out of carbon nanotubes like people want for a space elevator. One could pretty-much make it out of concrete, wood, metal, or glass and it would work fine.

Literally the entire 4 Gigatonne bridge could be sent from the ground to the same height as LEO for "only" 10-20 exajoules that would be stored inside it. (4.8 Gigatonnes of TNT or 1.27 Billion tonnes of H2+O2, 100 kg of anti-matter and 100 of matter, 34 tonnes of Thorium, or 370 tonnes of Uranium.)

In other words, look what we can do when we don't have to obey the rocket equation!

Any thoughts? have I made an error in my analysis? Is there something that makes this significantly more difficult than just simply making a massive particle accelerator inside something several times the length of the great wall of China built over oceans? Any idea how difficult it would be to keep circular and more-or-less in-place?

[Superfluous J]

Is there something that makes it more difficult than making a flexible particle accelerator larger than the Earth, that must pump 25 tons of material around 24x7x365 or it crashes back to the surface, out of concrete and wood?

No. Nothing makes it more impossible than it is inherently.

[CtrlAltEL1TE]

There is already a concept around very similar to this called an Orbital Launch Loop. It involves a ~2000km long cable suspended at ~80km by centrifugal force from a high speed rotor held within. The upside of this concept is it is extremely cheap to get objects into LEO with a gentle acceleration. The downsides being the cost of building and powering such a loop (it would need several large nuclear power plants dedicated to powering it), Also the fact that when any one of a thousand factors do not line up 100% i.e power drops for a millisecond or wind exceeds a certain threshold then the extremely high speed rotor may come into contact with the sheath causing an energy release (read; Explosion) somewhat similer to 350,000 tons of TNT).

Wikipedia article if you are interested: https://en.wikipedia.org/wiki/Launch_loop

Also these: https://en.wikipedia.org/wiki/Orbital_ring Dont know enough about them to explain the concept but it also seems similer to what you proposed.

Edited March 23, 2014 by CtrlAltEL1TE

[Whackjob]

There is also the interesting premise of the space fountain. To summarize, a tower held aloft by siphoning off kinetic energy from matter hurled at it.

[Pds314]

Is there something that makes it more difficult than making a flexible particle accelerator larger than the Earth, that must pump 25 tons of material around 24x7x365 or it crashes back to the surface, out of concrete and wood?

No. Nothing makes it more impossible than it is inherently.

It doesn't need to pump that matter around. The matter is moving at a significant fraction of the speed of light anyway and is moving through a vacuum.

It could be made of other materials, I'm just saying that you don't need materials like solid 20-meter-thick strings of carbon nanotubes to hold it in place like you do a space elevator.

Also, it has to be flexible, but no more flexible than, say, solid rock. It bends over distances of thousands of kilometers.

I'm not sure I'd call it impossible, especially when we consider the alternative prospect of making one that is actually rotating itself and is built tonne by tonne in orbit by conventional rockets.

There is already a concept around very similar to this called an Orbital Launch Loop. It involves a ~2000km long cable suspended at ~80km by centrifugal force from a high speed rotor held within. The upside of this concept is it is extremely cheap to get objects into LEO with a gentle acceleration. The downsides being the cost of building and powering such a loop (it would need several large nuclear power plants dedicated to powering it), Also the fact that when any one of a thousand factors do not line up 100% i.e power drops for a millisecond or wind exceeds a certain threshold then the extremely high speed rotor may come into contact with the sheath causing an energy release (read; Explosion) somewhat similer to 350,000 tons of TNT).

Wikipedia article if you are interested: https://en.wikipedia.org/wiki/Launch_loop

Also these: https://en.wikipedia.org/wiki/Orbital_ring Dont know enough about them to explain the concept but it also seems similer to what you proposed.

I've heard of this. My idea is basically a planet-wide flying version that is a little bit less explodifying (although it releases a lot more energy if it does explodify).

There is also the interesting premise of the space fountain. To summarize, a tower held aloft by siphoning off kinetic energy from matter hurled at it.

I've heard of these. This device would actually be rather similar to a giant one where instead of pushing against the ground, it pushes outwards from the planet on the opposite side.

Come to think of it, I wonder if I could make a demo of it in a physics engine... Or in real life with strings holding it down as opposed to gravity.

Edited April 23, 2014 by Pds314

[Aghanim]

Here is the thing: How do you maintain a structure that when power is cut off for several seconds, it explodes/falls? If the heavy ion beam (right? You wanted to use particle accelerator) touches the wall, the huge amount of energy will be dumped into the accelerator wall and that section would explode, then everything starts to fall down

And beamline alignment will be a nightmare.