
The sky's gone dark - pavel_lishin
http://www.antipope.org/charlie/blog-static/2015/09/the-skys-gone-dark.html
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ChuckMcM
This will be a very interesting question. There are some mitigating factors
however that make remediation a bit easier.

The first is that many, perhaps most of the satellites orbiting in LEO do so
traveling west -> east. That is because rockets use the Earths natural
rotation to get a free "kicker" to orbit. Thus entering orbit headed that
direction will be less dangerous than trying a different orbit, much like
entering the freeway in the direction of traffic is easier than trying to go
the opposite direction.

If the goal is cleanup then, you want want to reduce orbital velocity so that
the orbit gets lower and the atmospheric drag can pull things down.

Some simulations have looked at very fine mists of "soft" materials introduced
in a retrograde (opposite) orbit, as a way to rapidly degrade the orbits of
everything in LEO. Think of it as debris being hit by a million particles of
sand, none of which is enough by itself to deorbit the device but
collectively, over time, it transfers all of its momentum to the space junk.

In the ideal case X kg of "sand" in a retrograde orbit would deorbit X kg or
"junk" in the typical equatorial orbit. As the momentum was transferred from
the sand to the junk both would fall out of the sky.

That would only work for clearing a lane though. If you could create enough
space to clear a lane then you could launch something like NASA's laser
ablation idea which would travel in the same orbit as the remaining junk and
fire a laser at junk to impart some delta-V when the material ablates off the
junk.

Regardless two things are going to be true, its going to be a pain, and anyone
in orbit during the first cascade will die.

