Space Junk Decelerator


this idea is made of 2 halves.

(1) slowing down space debris by regular ice (water) or by dry ice (CO2). it turns out that unbeknownst to me, this 1st half has partly already been invented by aerospace engineer Jim Hollopeter (water).

https://www.treehugger.com/clean-technology/clearing-space-junk-from-earths-orbit-by-launching-water-at-it.html

http://www.nbcnews.com/id/33024322/ns/technology_and_science-science/t/agency-looks-ideas-clean-space-junk/#.XuEgbudS9PY

here is the short description from Google Books: Space Safety is No Accident: The 7th IAASS Conference (1.4.11. Ballistic Orbital Removal System) :


"According to James Hollopeter of GIT Satellite, rockets filled with water could be shot into space. After releasing their payloads in orbit, it would create a field of crystallized water that would be penetrated by orbiting junk, causing it to slow down, and fall out of orbit."

(2) concentrating the ice in the projected projectile path without touching the ice, by optical / electrostatic / microwave levitation. this 2nd half has never been invented before and it's necessary for the whole thing to work, so i can call it my invention.


"philosophical" background - how did i get this idea?

first of all, all the other solutions are based on a childish concept of "hunting" the pieces of junk: nets, harpoons, shooting it with laser, catching it with a sticky robot...

https://en.wikipedia.org/wiki/Space_debris#External_removal

these are not practical because the junk moves seven times faster than a bullet so it has a huge momentum. good luck catching it with something "hard" in front of it. as for the method of chasing it from behind, it needs fuel-expansive and time-critical maneuvering because it's already at this great speed.

so we need to think of something "soft" that is all over the place. the spaceships will be able to fly through this soft thing, by behaving unlike the junk.

the characteristic feature of space junk is it's speed. without this speed the junk could not maintain its course in its orbit.

so the spaceship will need to go slowly, like in the sci-fi serie "The Expanse" :

“If you go into a room too fast, kid, the room will eat you.” ... Somehow, Holden realizes that this means Alex needs to slow down and steer the ship into the ring. 

https://io9.gizmodo.com/the-expanse-just-delivered-its-most-unbelievably-tense-1826432922

so what do we have that can give this effect of: go fast equals stop, go slowly equals pass? the answer is Non-Newtonian fluid

https://en.wikipedia.org/wiki/Non-Newtonian_fluid

like in this video:

BRAINIAC Science Abuse - John Tickle Walks On Custard by brainiacstore
https://www.youtube.com/watch?v=BN2D5y-AxIY

however the more i though about it, the more i realized that with non-Newtonian fluid the point is that when the collision happens fast, the little particles don't have time to escape. but in our case with the space debris flying 7 times faster than a bullet, nothing has time to escape anyway. so a regular fluid like water is good enough.

so next i wanted to know how water behaves in space. there are many videos of playing with floating water blobs in the International Space Station (ISS) on Youtube, but these are not helpful at all, because of the air pressure inside the ISS, so the water remain a liquid like on Earth.

so then i found this nice article in Forbes that explains that it turns into a cloud of tiny ice crystals.

Water In Space: Does It Freeze Or Boil?
https://www.forbes.com/sites/startswithabang/2016/12/23/water-in-space-does-it-freeze-or-boil/#78d00e425f91

so the simple strategy would be to throw the water in front of the piece of junk, and to make an extended cloud through which the object will have to fly. the cloud of crystals slow down the object.

the problem is that on the next time it comes around the object moved quite a bit, exactly because we slowed him down. it will not fall to Earth, it will just stabilize on a lower area because it's still fast.

so the simple strategy, the one suggested by Jim Hollopeter is not good enough. how do we slow the object more?

(1) we can use more water in a naive way. imagine a huge spherical cloud that just goes to waste. this is not effective.

(2) we can use a stronger material like dry ice (CO2). i watched a few videos on Youtube and it can stop a bullet of Browning .50 caliber machine gun

https://en.wikipedia.org/wiki/.50_BMG

see this silly video

DRY ICE vs the FIFTY! (Mind Blown!!!) by DemolitionRanch

https://www.youtube.com/watch?v=Cnvw_5JlIcs

of course these are solid blocks and we use a cloud, but we use more length and we just need to slow it down considerably.

this solution is good for what we need, the only drawback is that i don't know how it will effect the greenhouse effect. as you know we have a heat "blanket" around Earth that traps the heat inside which is CO2. so dry ice is CO2 so on the one hand we can "get rid" of CO2 that we dump in our atmosphere anyway which is very harmful here on Earth, and throw it into space and achieve something good with it. on the other hand, i don't know how the CO2 will behave: will it be like a greenhouse inside a greenhouse? so since we don't understand this perfectly then this is too risky!!! not good.

(3) we can use more water in a non-naive way. imagine a long "tunnel" without walls filled with cloud and the tunnel's path predicts the path of the object. this is effective.

(4) we can use a short "tunnel" or cloud and move it to meet the object the next time it comes around again and again. this is much cheaper than flying after the object. in order to intercept the object we just move towards Earth the difference between the old radius of the object and the new radius of the object. this is effective but less than (3).

of course if we are very optimistic we can combine (3) and (4). make a long "tunnel", or even a complete circle "tunnel", that shrinks again and again following the current radius of the object. but i think this is the same kind of childish optimism that our hunting friends relied on, so from now on i will focus on method (3).

 

how do you catch a cloud and pin it down? ("Maria" from "The Sound of Music")


we need to shape the cloud "tunnel" in space. we cannot build a box or an actual tunnel around the cloud, because that would itself become junk in space. so how do we keep the cloud in place without touching it?

we have the same problem as someone trying to hold something up in the air without actually touching it. this is called levitation. there are methods of levitation that rely on air, like for example sound waves. these are NOT good for our purposes, because space doesn't have air, so the sound waves cannot travel in space. but i just bring this video because it shows nicely what levitation is. we will use other methods of levitation that will give us the same result.

I built an acoustic LEVITATOR! Making liquid float on air by Physics Girl

https://www.youtube.com/watch?v=ABjRnSYw-4k

so i searched in this book:


The Airborne Microparticle: Its Physics, Chemistry, Optics, and Transport Phenomena

by Prof. E. James Davis, Prof. Dr. Gustav Schweiger

Springer-Verlag 2002

and found out about this article which is excellent:

Ernst Helmut Brandt (1989) Levitation in physics. Science 243:349-355

it describes:

Aerodynamic Levitation, Acoustic Levitation, Optical Levitation, Electric Levitation, Magnetic Levitation, Radio-Frequency Levitation, Superconducting Levitation


i think we should use the fact the water molecules have dipole so they have a plus side and a minus side, so maybe we can move them in space inside an electric field.

also another very interesting thing we can do is pass electricity throw the water, this can help them "bridge" over and to some extent even overcome gravity:

How To Defy Gravity With Water | THE WATER BRIDGE EXPERIMENT| by  Plasma Channel

https://www.youtube.com/watch?v=6ZzuFGw4XCg

in space it's easier for the electric current to form an arc from one piece of water to the other, it will be like the lightning passes through air, but through vacuum. i hope it will have the same connecting together effect that we see in the video.

and in Google Books i also found this article:

NASA Tech Briefs September 1991 page 61 - Microwave Levitation of Small Objects.

https://books.google.co.il/books?id=I9zIJX33gCQC&pg=RA8-PA61&lpg=RA8-PA61&dq=levitating+microwave+vacuum&source=bl&ots=LaCxeI9Ovd&sig=ACfU3U3-rKzA2sLaS8NTXjUCSZ0Kfl4Rmw&hl=en&sa=X&ved=2ahUKEwixudfj9PfpAhWXVRUIHRZqDfcQ6AEwBnoECAYQAQ#v=onepage&q=levitating%20microwave%20vacuum&f=false

so using such methods we can trap the water like in a Quadrupole ion trap

https://en.wikipedia.org/wiki/Quadrupole_ion_trap

see in this nice video:

Homemade Paul Trap by  Nick Moore
https://www.youtube.com/watch?v=u_OlVz95_tw

PLEASE NOTE: we are not controlling the object (space junk) with these gentle effects of "no hands" levitation. instead we are controlling the water cloud and give it the optimal shape of the path of the object. then we leave the water floating there, and after a few seconds the object (space junk) hits the water.

i'm thinking of this "controlling" of the cloud like the super conducting magnets that we use in particle accelerators like CERN to bend the particle beams without touching.

by the way the big money in super conducting magnets is keeping them cool, so since space is very cold, at least where and when the Earth shades us from the Sun, then maybe we can build super conducting magnets.

so we can make a loop of wire like a collar around the path, and move it along the cloud to shape it, with the electrical current that we run through the loop of wire.

and then before the object comes flying by we turn off the current in through the loop of wire, and take the loop of wire away so that it doesn't get ruined by the object.

another thing we can use is transmitting the microwave energy from "drones" that are located around the cloud, like the wire but more "loose", at some distance so the drones will not be damaged.

we can slide the collar along the cloud and so we maintain the shape of the cloud "tunnel".

to form the shape of the collar we can have the wire rolled up inside a drone, like the electric cable of the vacuum cleaner is rolled up with a spring and you can pull it out manually and once you're finished with the vacuum cleaner you press a button and the spring rolls it back inside. so the two wires will be pulled "manually" by another drone and the drones will push each other gently away from each other. this will give us two parallel wires. in order to spread the wires away from each other we can pass electricity through them like in this nice video.

MIT Physics Demo -- Forces on a Current-Carrying Wire by mittechtv
https://www.youtube.com/watch?v=43AeuDvWc0k

the second drone then attach a very short wire just to shortcut the two wire ends that he holds, and then the first drone runs electricity through the whole ring. in order for the ring not to collapse back, we can help with two more drones, that will just hold the middle sections open apart.


how do we get the water up to space and how do we get the water down to Earth?

i think we should lifting the water to space without the use of rockets, because we can use a cheaper method and we don't care how much G force the water endure, unlike astronauts.

https://en.wikipedia.org/wiki/Non-rocket_spacelaunch

i think we should make ice blocks (freeze the water) shaped like big bullets and shoot them to space with a solar powered electromagnetic catapult

https://en.wikipedia.org/wiki/Mass_driver

in space the ice "mortar shell" will disintegrate because it turns to cloud, but this cloud keeps going because it has the same inertia forward and nothing stops it. as for how fast we need to shoot the ice bullet we can calibrate it after a few failed attempts. the material is see water and with the rising sea water we have plenty of it. in order to stop the cloud at the end of the journey when it's relatively slow we direct the "levitation" technology in the opposite direction of the bullet's flight, until the bullet stops.

on the way back to Earth, the nice thing about this solution is that the water just fall back to Earth like clouds and rain.