Re:Bi-Directional Plasma Thrusters for Space Debris Removal
by Hupriene on Friday September 28, 2018 @07:52PM
(#18097910)
The space stations we've built have all been in LEO. The ISS would deorbit in less than two years without periodic boosts. As such, no nearby orbit can be considered stable. The fuel required for boost is proportional to its mass. So it's quite reasonable for space programs to cast of 'dead weight' that doesn't contribute to the mission of the space station.
Re:Bi-Directional Plasma Thrusters for Space Debris Removal
by russdill on Friday September 28, 2018 @09:53PM
(#18098292)
The number one use of atoms in space is to generate delta-v. Sure the ISS could ionize it's waste and use the thrust to maintain it's orbit, but collecting other waste would require delta-v or impart unwanted delta-v (as with the atmosphere)
It's a bit of flatlander nonsense that should not be brought off the surface. I was shocked as hell when I found out astronauts vent trash and waste.
"Come, let us reason together."
There are not a lot of atoms in space, by definition, compared to terrestrial conditions. (Okay, technically all atoms are in space. You know what I mean. ;-P ) So, if you have some atoms together in space already it's just stupid to disperse them into small bundles and then lose track of their orbit. (You can't throw things away in space, you can only lose track of them. They'll be back.)
It takes a lot of energy to get a bunch of atoms to orbit from the surface. It's wasteful to discard "waste"! (Say it with me, "No waste in space!") Literally, in space, matter is only "waste" because you let go of it and stopped paying attention to it. It's still useful, just not to you right now. Even if you're sure you'll never have a use for it, it's criminally irresponsible to "throw away" matter in space. It's like firing a gun into the air: that bullet is coming down somewhere... At the very least bundle it up and tag it with a radar reflector or something.
In conclusion, space is big and empty and curved, atoms are rare, important, useful, and expensive to bring with you. Keep them nearby and on stable orbits. That way you don't have to waste energy collecting them again and they aren't rattling around forming a collision lottery in LEO.
No waste in space.
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Now then, as a bit of a tangent, are you familiar with the "spittlebug", Cercopoidea? Their nymphs form nests of bubbles that look like little blobs of spittle. I say this is the correct design for space vehicles and stations. Spittlebug nest. Not metal can. Cheap, simple, ridiculously easy construction methods, durable, self-repairing, reusable, flexible, etc... I'm sure we could make materials that permitted different kinds of bubble, for e.g. storage, blocking radiation, absorbing collision energy, etc...
So, build your space stations out of bubbles. If you do it right you can collect debris for free. (Hint: you have to intersperse threads with your bubbles and have the right kinds of glue and stick'um. It's all down to materials science at this point, the spittlebug design doesn't really have any other constraints. You could make a space vehicle that "landed" by simply crashing. Density of the atmosphere and the vehicle would determine velocity at touch down. Or, you just make the bubble nest really big. Like 10K diameter. Then when you "crash" your core ship (which actually might be a metal can) settles to the ground through ~5k of bubblewrap.