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Small space debris is a serious problem. I think that if a large container orbits full of space debris and sweeps up small pieces of space debris that fit into the container, the space debris can be cleaned up cleanly. Why is this method not used in practice? In what ways is it limited and in what ways is it inefficient?

Organic Marble
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전현서
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    It's like catching flying bullets with a dust pan. – Alexander Feb 11 '24 at 03:40
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    In addition to the problems already stated in answers, there is the additional challenge of sweeping space debris without sweeping spacecrafts and satellites. – Pere Feb 11 '24 at 12:27
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    This is analogous to using nets to catch fish in the ocean, except the fish are moving at thousands of kilometers per hour and also the fish are all hundreds or thousands of kilometers away from each other. You need either an absolutely enormous net or you need to make an enormous number of passes, catching only a tiny number of fish per pass. – chepner Feb 11 '24 at 16:50
  • @Alexander or birdshot, because there are a lot of them and all spread out.. – Conrado Feb 12 '24 at 16:11
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    Why is this question attracting downvotes? – gerrit Feb 13 '24 at 08:00

3 Answers3

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The problem is that every bit of space debris is in its own orbit. If you want to match that orbit, it takes a lot of fuel. If you don't do that, and you just intercept it, you will find that the debris is flying at a high speed (several km/s) compared to you. This means the debris will punch a hole through your container, like a bullet, instead of being caught.

Hobbes
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    “Space is big. Really big…” which is a whole other problem as well… – Jon Custer Feb 10 '24 at 17:09
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    "This means the debris will punch a hole through your container" … and create an additional order of magnitude of orbital shrapnel in the process. – Jörg W Mittag Feb 11 '24 at 10:57
  • @JörgWMittag: Depending upon the masses, velocities, and construction of the objects involved, I would think a collision could impart a substantial radial component of velocity; small objects with eccentric orbits whose perigee is below the top of the atmosphere won't remain dangerous for very long. – supercat Feb 12 '24 at 21:48
  • Actually it's misleading to say it would punch a hole like a bullet would. The debris is much faster than a bullet, which makes for some important differences: when it hits the container, both the debris and the spot it hit instantly vapourize. That's kind of a good thing because this vapour itself would eventually disperse harmlessly, the problem is that it first expands explosively which generally means a whole lot of fresh debris is ripped out of the container, with the result that you have a lot more space debris orbit after the collisions than before. – leftaroundabout Feb 15 '24 at 22:26
  • ...One solution would be to make the container out of ice: the shards would then automatically sublimate and effectively vanish from orbit. – leftaroundabout Feb 15 '24 at 22:28
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Sweeping up space debris in orbit is a bit like sweeping up bullets in mid-air in the middle of a machine-gun fight, except the debris is probably moving faster (relative to the sweeper) than the bullets.

mhoran_psprep
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Steve Linton
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    https://i.stack.imgur.com/Zd3fj.png – uhoh Feb 12 '24 at 02:05
  • The debris is also farther apart than the bullets. – gerrit Feb 13 '24 at 07:59
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    It's a bit more like protecting Elephants, and Rhino's, and polar bears, and penguins, and several other species, by employing just one man with a single small bullet-proof shield. – MikeB Feb 13 '24 at 09:38
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From a diplomatic perspective: you say space debris cleanup, I hear anti-satellite weapon.

If you announce you have the capability to do this, you are going to attract the attention of all the major spacefaring powers, who have invested heavily in their satellites and rely on them for both civilian and military purposes. If you are one of them, you risk starting an arms race and accelerating the militarisation of space.

user3490
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