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URL: https://www.shado-forum.com/and-the-space-junk-issue-gets-worse-and-worse-tp3303668p3314337.html

there is another way, a material of somekind could be sprayed onto the junk, in bombs or piece by peice, then the stuff would either collide and assemble into larger masses, or be pulled with a magnet attracted by the magnetic material coating on the junk,
i would assume that standard bombs would work, even just steam bombs to billard break them into colliding into each other and then allow the peices to fall into re-entry.
jim

From: griffwason <[hidden email]>
To: [hidden email]
Sent: Tuesday, September 6, 2011 8:08 AM
Subject: [SHADO] Re: ...and the space junk issue gets worse and worse...


 
Hi,

How about this...

According to NASA, the equivalent mass of twice the ISS has had to be moved to avoid potential collisions in earth orbit! Space junk means everything from rocket upper stages weighing several tons down to the odd spanner lost in space by space-walking astro- or cosmonauts. Friction and gravity will eventually bring all the space junk back to earth, but will take centuries.

What's the solution? It won't be easy. We can't shoot it down, because even if we are accurate enough to hit the junk all we are likely to accomplish is blasting it into lots more smaller pieces that will need tracking. We could shoot it with high-powered lasers, but unless we were able to vaporize the debris completely, all we'd be doing is boring very nice holes in it. No, we have to gather the stuff and bring it back to Earth. But how?

Space junk collector: a very fine net to capture the debris and hold it. The net could be built from kevlar or carbon nanotubes. Nanotubes have the highest strength-to-weight ratio of any material and would allow for a very large, very light weight net. Our point here is to make the net light rather than strong, since our capture speeds will be low and the lack of gravity ought to make it easy to keep the junk tethered together. The point of making it strong, then, is so it can be light enough to be big enough to maybe gather all the junk — all 18,000 pieces — into a single mass.

Launch collector into an inclined polar orbit generally higher than the space junk to be harvested. The polar orbit will ensure that eventually the collector will go over every spot on the Earth as the planet rotates below, but it also means the collector will eventually cross the path of every piece of space junk.

Here's where we need an algorithm and a honking big computer, because this is a 3-D geometry problem with more than 18,000 variables. Our algorithm determines the most efficient path to use for gathering all 18,000 pieces of space junk. It would start in a high orbit, above the space junk, because we could trade that altitude for speed as needed, simply by flying lower, trading potential energy for kinetic.
Dragging the collector behind a little unmanned spacecraft would be to go past each piece of junk in such a way that it not only lodges permanently in the collector, but that doing so adds kinetic energy (hitting at shallow angles to essentially tack like a sailboat off the debris). It wouldn't always be possible, of course, to gain energy from each encounter, but that's why it would need to start in a higher orbit, so as energy is inevitably lost it can be replenished by moving to a lower orbit.

It would logically start with smaller bits of space junk so the net would gain mass steadily over time, then do the same again at each lower altitude. Eventually the collector would have corralled hundreds of tons of debris, carrying it down into the atmosphere where atmospheric friction would eventually burn it all up in a spectacular visual display that would create a thin ring of fire all around the Earth.

Crazy idea, sure, but it could work. Small to big, high to low, all it would take is time. How much time? If the collector orbits every 90 minutes and it takes an average of a dozen orbits to set up the capture of each piece of space junk, that's 18,000 * 90 * 12 = 19.4 million minutes or 36.9 years to get it all.

Mmm... that's about how long it took to put all that junk up there in the first place.

G




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