The US government's High Frequency Active Auroral Research Program (HAARP)(1), a favorite subject of conspiracy theorists, uses a high frequency, high-power transmitter to temporarily excite a small part of the ionosphere. One theoretical use for HAARP is to produce an ion outflow that drags oxygen up to 800km and could be used to enhance the drag on orbiting satellites (and presumably debris as well), de-orbiting them faster.(2)<p>1) <a href="https://en.wikipedia.org/wiki/High_Frequency_Active_Auroral_Research_Program" rel="nofollow">https://en.wikipedia.org/wiki/High_Frequency_Active_Auroral_...</a><p>2) <a href="https://www.nap.edu/read/18620/chapter/6" rel="nofollow">https://www.nap.edu/read/18620/chapter/6</a>
When I first read about SpaceX's plan to launch up to 42,000 satellites, I actually wondered if we'd end up with a night sky filled with artificial objects. Then I looked at the size of the earth: 197,000,000 square miles. Which is basically one satellite for 4,690 square miles. And that's at ground level. Add in more distance for low earth orbit height, and it becomes even bigger. The cubic space between two of these objects (which I'm not sure where to begin to calculate) must be pretty massive.<p>The sky is huge. And though it's probable that one thing will hit another up there, it doesn't seem <i>very</i> probable, even if something were to explode into a billion tiny bullet -like projectiles.
Serious comment: I've thought about this idea a lot since I heard about it, and my mind immediately goes to "can't we deflect these things?"<p>Assuming that the dangerous orbiting debris is in a few "layers" (like a shell at a certain distance from the earth) which conflict with satellites operating at the same layer, it should only come in at any of 360° angles on a semi-2D plane. Like, it's not going to strike a satellite from much of an angle above or below, because then it would by definition not be in orbit, correct?<p>Could we not reasonably launch a series of deflective plates or shields in the same plane through the "danger zones" encircling important satellites, or creating a safe zone for passage with shuttles?<p>Obviously we can't create a ring around the entire globe, nor protect all satellites, but it seems that a few well-placed shields in the worst areas would accumulate a growing "cleanup score" over time.
Shouldn't most of the pieces from a collision in LEO crash into the earth? If you consider a plane tangent to the altitude of the object, most pieces ejected below that plane should reenter and burn up. Any piece ejected outward will be in an orbit that will return to the collision point from underneath and must therefore hit the earth. Only parts ejected nearly in-plane will have lasting orbits. That's not to say it wouldn't be a problem.
Is this a solvable problem? Can you launch a steel plate of 8000 kg and attach thrusters to it, and drive it into known objects? Occasionally refuel the thruster module. I'm guessing a 1/2" steel will absorb some pretty significant energy. Make it 1" steel in the vicinity of the guidance thruster system. Have a plan to deorbit the steel in sections. It's essentially a filtration system.
There's a great short story that makes use of this in its setup. Lostronaut, published in the New Yorker in 2008: <a href="https://www.newyorker.com/magazine/2008/11/17/lostronaut" rel="nofollow">https://www.newyorker.com/magazine/2008/11/17/lostronaut</a>
For lovers of anime and hard sci-fi, Planetes is a very good series exploring the issue: <a href="https://www.imdb.com/title/tt0816398/" rel="nofollow">https://www.imdb.com/title/tt0816398/</a>
It's interesting that inevitably we will reach a `critical-mass` of this debris and a chain reaction will result.<p>The fact that paint-chips travel at sufficient velocity to cause damage, I somehow doubt that even the most wild guesses as to the actual amount of debris is accurate. It must be several orders of magnitude too low.<p>A lot of theories have been proposed to de-orbit these hazards, personally I think our only hope is MegaMaid.