# Discussion: Effective way to clean up our space junk



## LordOfWizards (Oct 24, 2017)

We've all thought about this from time to time. Let's discuss it:
How can humans clean up our space junk?


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## Mirannan (Oct 24, 2017)

One idea I've seen is that of a big ball of something like styrofoam, in a retrograde orbit, in whatever orbit you want to clean up. It would work like this:

Really small pieces (paint flakes and the like) hit the foam and are simply absorbed, transferring their momentum to the ball.

Larger pieces blow chunks off the ball and either don't get through (see above) or do get through, but travelling quite a lot slower - probably enough slower that before very long they re-enter. If the speed loss isn't enough then they encounter the ball again on the next go around. The blown-off chunks will probably re-enter.

After a while, the ball itself has lost enough speed that the ball itself re-enters - it helps that it is not very dense, so air resistance is significant. One gets a rather pretty meteor shower, when the chunks of styrofoam plus its load of assorted millimetre-sized junk hit the atmosphere.


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## LordOfWizards (Oct 25, 2017)

Mirannan said:


> ... big ball of something like styrofoam...


 I like it, but with the "about 500,000 pieces of junk a half inch across and larger, according to NASA estimates." I think we would need a lot of _big_ styrofoam balls. 

One idea I haven't fully refined yet is a fairly large electromagnetic vehicle since a lot of what we've thrown up there is metal. Then again, there may be a fair bit of aluminum which would not be picked up. Anything we use will need to be thrusted properly to give it the right speed (nearly match the speed of the debris with a slight offset).


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## BAYLOR (Oct 25, 2017)

LordOfWizards said:


> I like it, but with the "about 500,000 pieces of junk a half inch across and larger, according to NASA estimates." I think we would need a lot of _big_ styrofoam balls.
> 
> One idea I haven't fully refined yet is a fairly large electromagnetic vehicle since a lot of what we've thrown up there is metal. Then again, there may be a fair bit of aluminum which would not be picked up. Anything we use will need to be thrusted properly to give it the right speed (nearly match the speed of the debris with a slight offset).



This is problem that not going to go away anytime soon.


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## Danny McG (Oct 25, 2017)

In less than six years our true Masters shall complete their voyage.
Once they are here such trivialities will no longer be the concern of us Chosen who survive the Great Winnowing


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## Mirannan (Oct 25, 2017)

LordOfWizards said:


> I like it, but with the "about 500,000 pieces of junk a half inch across and larger, according to NASA estimates." I think we would need a lot of _big_ styrofoam balls.
> 
> One idea I haven't fully refined yet is a fairly large electromagnetic vehicle since a lot of what we've thrown up there is metal. Then again, there may be a fair bit of aluminum which would not be picked up. Anything we use will need to be thrusted properly to give it the right speed (nearly match the speed of the debris with a slight offset).



Yes, a lot would be needed; but in any case, whatever ends up being used it will be a major effort. Of course, the inflation of the foam would be done in orbit.

Another idea I've seen is to pump lots of energy into the ionosphere (maybe using a really big radio transmitter built for the purpose?) so that the atmosphere swells enough to make at least the lower edge of the swarm deorbit by itself. Of course, there would be other effects, and I'm not sure anyone knows what they would be.


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## DelActivisto (Oct 25, 2017)

High powered lasers? Maybe they'd tear apart the atmosphere?


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## Mirannan (Oct 25, 2017)

DelActivisto said:


> High powered lasers? Maybe they'd tear apart the atmosphere?



Maybe they would work too. Incidentally, something like this happens naturally when the Sun is more active. The increased energy being dumped into the upper atmosphere affects it enough that satellite orbits can be affected. Which can be a concern, because it shortens their useful life - because they need to use more station-keeping propellant.


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## Vertigo (Oct 25, 2017)

There's an awful lot of empty space in between those 500,000 bits of debris. I think any sort of big ball would spend the vast (and I really do mean vast) amount of it's time not hitting anything, also I think it would be a very fine balance between capturing debris or debris going straight through it. This stuff is seriously motoring! Equally I think there will be very little ferromagnetic material up there.

They have plans for using lasers so that is a possibility but would probably just turn big bits of debris into smaller bits which can still do lots of damage.

Maybe they'll come up with a fine enough and strong enough material to construct vast nets multiple kilometres in diameter that can be dragged through areas with high densities of debris.


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## Mirannan (Oct 25, 2017)

Vertigo said:


> There's an awful lot of empty space in between those 500,000 bits of debris. I think any sort of big ball would spend the vast (and I really do mean vast) amount of it's time not hitting anything, also I think it would be a very fine balance between capturing debris or debris going straight through it. This stuff is seriously motoring! Equally I think there will be very little ferromagnetic material up there.
> 
> They have plans for using lasers so that is a possibility but would probably just turn big bits of debris into smaller bits which can still do lots of damage.
> 
> Maybe they'll come up with a fine enough and strong enough material to construct vast nets multiple kilometres in diameter that can be dragged through areas with high densities of debris.



I agree that most of the time would be spent doing nothing. You in a hurry?

Regarding the stuff going through - well, yes. But two points about that - the really small stuff wouldn't (especially if the sweeper is really big, say 100m across) and even the stuff that went through would be slowed down. After a few hits, something like a loose glove or bolt would be slowed down enough that its perigee would be in the fringes of the atmosphere - and then down it goes.

The easiest way to get rid of the small pieces of junk is to make them deorbit. Big chunks (rocket boosters and the like) are another matter, but by the very nature of the problem there aren't all that many of those.


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## Vertigo (Oct 25, 2017)

Mirannan said:


> I agree that most of the time would be spent doing nothing. You in a hurry?
> 
> Regarding the stuff going through - well, yes. But two points about that - the really small stuff wouldn't (especially if the sweeper is really big, say 100m across) and even the stuff that went through would be slowed down. After a few hits, something like a loose glove or bolt would be slowed down enough that its perigee would be in the fringes of the atmosphere - and then down it goes.
> 
> The easiest way to get rid of the small pieces of junk is to make them deorbit. Big chunks (rocket boosters and the like) are another matter, but by the very nature of the problem there aren't all that many of those.


Well if something isn't done soon we might be in a hurry  but I take your point. However you would also need to be able to modify its orbit so it can clear more than one altitude.


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## LordOfWizards (Oct 25, 2017)

dannymcg said:


> In less than six years our true Masters shall complete their voyage.



Perhaps the space debris will protect us from our "true Masters".


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## LordOfWizards (Oct 25, 2017)

Vertigo said:


> Well if something isn't done soon we might be in a hurry ...


I agree emphatically. That's why I posted the thread. I imagine we will continue trying to get to Mars, explore other parts of the local system, and eventually build a space elevator. 

A little way down into the article I linked, there is this video of a planned mission to explore different ways of getting the job done.


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