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Using Lasers and Water Guns To Clean Space Debris
WSJdpatton writes "The collision between two satellites last month has renewed interest in some ideas for cleaning up the cloud of debris circling the earth. Some of the plans being considered: Using aging rockets loaded with water to dislodge the debris from orbit so it will burn up in the atmosphere; junk-zapping lasers; and garbage-collecting rockets."
Not only would lofting water into space be a colossal waste of energy and water, it would only exacerbate the problem!
IMHO the only 'clean' way to deorbit debris is to add energy to the debris in the retrograde direction without using additional mass, which means photons. Laser pulses could do it either by radiation pressure directly (huge laser), or by pulses that ablate the debris slightly (creates tiny beads of additional debris).
Electron/proton beams would work as well, as would alpha particles, but they'd pose a risk to humans in space. In fact, using charged particles might induce a charge on the debris that would then help direct the debris toward it's doom (debris vector, Earth's magnetic field, right hand rule....whatever).
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
http://en.wikipedia.org/wiki/Planetes
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True, most only really think of oil as being the next big thing to cause mass hysteria, but few realize that potable water is a dwindling resource in certain regions. Even the giant Ogallala aquifer in the central United States is showing increased rate of depletion (not to mention pollution).
There are a few books on the subject.
This is a good point. But as collisions become more and more frequent, I don't think they be able to maintain momentum. The energy from each collision is spread out among all the fragments produced, and also some is lost during the impact as heat and the energy required to separate the fragments from the larger original pieces.
Let's say that "first-generation" objects are on a stable orbit with sufficient momentum to maintain orbit. After impact, some of the resultant second-generation fragments will fail orbit quickly due to grossly incorrect trajectories, while others enter trajectories that will take longer to fail. Over the time it takes for these second-generation fragments to fail, they cause more impacts. More of these third-generation fragments are lost more quickly, and the remaining ones proceed to cause fourth-generation impacts, and so on. This is the general chain-reaction idea being posited.
One factor to consider is the fact that as these particles reach higher "generations", they are in more and more grossly failing trajectories due to either bad vectors or insufficient momentum. These trajectories intersect less and less with stable orbits, so the collisions are more and more likely to be with already-failing particles. This could only accelerate the orbit failure. Essentially, these particles should clean themselves up.
Again, I am no astrophysicist, but it seems that if chance supported easily-achieved orbits, then we would already be at saturation. The fact that we're not suggests that the "random collisions creating a permanent* cloud of debris" theory may not be self-supporting.
Of course, it may be that the time it takes for this debris field to fail is on a scale which is inconvenient to us. But to say that we'll eventually end up with a stable cloud of microscopic bits just doesn't add up.