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Using Lasers and Water Guns To Clean Space Debris
Posted by
CmdrTaco
on Wed Mar 11, 2009 10:00 AM
from the super-soaker-one-million dept.
from the super-soaker-one-million dept.
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."
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Water is heavy (Score:5, Insightful)
Re:Water is heavy (Score:5, Insightful)
Wouldn't it be extremely expensive to send large quantities of water into orbit (also, our water supply is limited we can't be throwing it into space!)?
But it rains! The water will come right back down eventually!
Don't question me. My logic is flawless.
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Re:Water is heavy (Score:5, Funny)
Damn! Shut up already! The average moron will totally believe your rain concept.
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Re:Water is heavy (Score:5, Insightful)
Damn! Shut up already! The average moron will totally believe your rain concept.
Apparently they do, I just was modded insightful.
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Re: (Score:3, Funny)
Actually, it is likely that a lot of the water will come back to earth. In a LARGE number of years. The reason is that it will be used in LEO, and will have a relatively slow speed. IOW, it WILL come back slowly to earth.
Quiet, you. You're bringing logic to this conversation.
Water should return QUICKLY. (Score:3, Interesting)
Actually, it is likely that a lot of the water will come back to earth. In a LARGE number of years.
Most of it will come back immediately. The water spray itself, aimed to transfer momentum to the debris in order to deorbit it, should itself be in an atmosphere-intersecting trajectory. The bulk will miss and end up in the atmosphere.
What gets blasted into steam will still be deep in the gravity well. Most of it will be perturbed into denser atmosphere in reasonably short order. (Remember: The atmosphere
Re:Water is heavy (Score:5, Funny)
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Re:Water is heavy (Score:4, Insightful)
Fine, use a powder made from AOL trial CDs. That's a limitless resource.
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Re:Water is heavy (Score:4, Insightful)
Now, our fresh-drinkable-water supplies in places that they can be effectively used for agriculture, industry, or residential populated areas, sure, that's an entirely different story altogether.
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Re:Water is heavy (Score:5, Interesting)
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 [waterencyclopedia.com] aquifer in the central United States is showing increased rate of depletion (not to mention pollution).
There are a few [amazon.com] books [amazon.com] on the subject.
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Re:Water is heavy (Score:5, Funny)
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Re: (Score:3, Insightful)
Re: (Score:3, Funny)
Bah! We already send large quantities of water into orbit - astronauts! How about using the urine they produce to alter the orbits of space junk? Anyone have an idea on how to let an astronaut piss out of their spacesuit without decompressing?
Re:Water is heavy (Score:5, Funny)
The water is actually for the sharks. Space-junk shot by lasers, lasers go onto sharks, sharks go into water, water goes into space. Keep up, this isn't rocket science...
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Re: (Score:3, Insightful)
It will freeze, but sublimation will take care of the problem.
Re: (Score:3, Insightful)
Re:Water is heavy (Score:4, Insightful)
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Re: (Score:3, Insightful)
Re: (Score:3, Insightful)
H is the most abundant chemical in the universe, but much of it is tied up in bodies, and space is huge. You'd have to spend an awful lot of effort to collect even a gram of the stuff.
Your comments about radiation seem to be directed elsewhere. The GP was about the limited supply of water.
Good (Score:2)
http://science.slashdot.org/article.pl?sid=08/09/05/1231228
Well, armchair rocket science here... (Score:3, Insightful)
But aren't all of those 'solutions' already considered?
Space garbage zapping: You'll end up with particles and debris that is smaller and more difficult to track. Given a speck of paint in space has the same effect as a bullet on earth I don't know if we really want that.
Space garbage collecting: However you try to do it, your spacecraft would have to either maneuver very very well in order not to be destroyed itself (making even more debris) or have such heavy shields that would make it nigh impossible to get into space.
Space pushing into the atmosphere: Just like garbage collecting, your spacecraft will have to be careful. On the other hand it would also be possible that with a slight miscalculation you push it into an orbit that's either much more dangerous (if it bounces instead of incinerates) or more difficult to track and clean up. Next to that some things might just give other side effects here on earth. What do you think would happen if you push an old satellite with some type of nuclear fuel into the atmosphere and it doesn't burn up completely the way you want it to and it basically becomes a dirty bomb in high orbit.
Re:Well, armchair rocket science here... (Score:4, Funny)
ZOMG!!!! You're giving terrorists ideas!! I'm reporting you!!!
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Water???? (Score:5, Interesting)
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).
Re:Water???? (Score:4, Informative)
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).
You do know that electrons/protons/alpha particles have mass, right?
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genius at work (Score:3, Insightful)
Wow. Just, wow.
Re:genius at work (Score:4, Funny)
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Re: (Score:3, Funny)
PlanetES (Score:5, Interesting)
Laser Broom (Score:3, Informative)
To be clear, they are not talking about blowin' up space junk with lasers. The laser will instead slow down small pieces of space debris so that their orbits deteriorate. (Blowing things up is the domain of the other Project Orion [wikipedia.org].)
This mechanism is called a laser broom, and there is a short entry [wikipedia.org] about it on Wikipedia. I can't seem to find a more detailed, technical description of how this process works.
Just keep launching junk into orbit (Score:3, Funny)
Project Orion "Laser Broom" is best option (Score:3, Informative)
The proposed Orion space debris laser fits nicely with our recent problems of creating so much debris in LEO. It would be a single pulsed laser on an equatorial mountaintop capable of ridding LEO of hazards in 4 years.
With the recent collisions this is becoming imperative. We need to have a clean LEO environment or we aren't going to do much in space.
http://www.spacefuture.com/archive/orions_laser_hunting_space_debris.shtml
http://adsabs.harvard.edu/abs/1997SPIE.3092..728P
http://en.wikipedia.org/wiki/Laser_broom
http://cat.inist.fr/?aModele=afficheN&cpsidt=3109525
Water makes a great shield inside a space station but is a dumb idea for "collecting" debris.
I trained for this in college (Score:5, Funny)
OS/400? VMS? TSO/ISPF? UNIX? (Score:3, Funny)
Re:Obrigatory (Score:5, Funny)
> Sharks can fly to space?
That's what the water is for.
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Re:Water.... (Score:4, Informative)
I thought that number sounded a bit high as a gallon only weighs about 7 pounds, but sure enough, a cubic foot of water DOES weigh around 60 lbs. 62.42796 pounds [fourmilab.ch] to be exact. And a gallon is actually just over 8 pounds.
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Re: (Score:3, Informative)
The main problem with imperial units (apart from the aforementioned different standards in different parts of the world) is that there are so many units for a single measurement. Length can be measured in inches, in feet, in yards, in furlongs, in fathoms, in rods, in chains, in miles, and who knows how many others. Volume is even worse. Not only do you have teaspoons, tablespoons, ounces, cups, pints, qu
Re: (Score:3, Interesting)
Orbital mechanics work in strange ways. For example, in a circular orbit, you don't thrust up to go up, you thrust forward. Going down, you thrust backward.
In this case, your best bet will be to hit the forward side of the object. If that's not possible, then hitting the bottom of it (depending on where it is in the orbit) will also have an effect. I can't remember offhand what happens from in-plane radial delta-V application, but I think it's a combination of changing the eccentricity of the orbit with
Re:Huh? (Score:5, Informative)
Since space is a "near" vacuum wouldn't the water flash to steam instantly and be useless?
The enthalpy of vaporization for water is very large. On exposure to vacuum, immediately the water will begin to boil. This will very rapidly cool the water so that most of it ends up freezing (the enthalpy of fusion is comparatively much lower). Not only does this make mathematical sense, but it's witnessed daily on vacuum lines in labs.
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Re:Ok, now serious, really (Score:4, Interesting)
Doesn't work. The impactors will just break loose pieces of the ice. There has been some thought put into using Aerogel, since it has density low enough to not explode when hit by something going very. fucking. fast.
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Re:Frickin' lasers? (Score:5, Funny)
Which puts us one step closer to landsharks.
*knockknock* "Plumber!"
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Re:Water? (Score:4, Insightful)
Given the price of launching things to space, you could use scotch whiskey instead and it wouldn't affect the cost or feasibility of this plan.
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PURE water, please! (Score:3, Interesting)
Send up seawater.
Distill, reverse-osmosis, or otherwise purify it first.
I'm normally one to debunk hand-wringing about the ozone layer. But most of the sprayed water will miss the debris and impact the upper atmosphere immediately (while the rest comes down slowly over many years). If you use unpurified sea water you'll put a LOT of chlorine ions from sea salt into the ozone layer - near the equator where it's a big deal - and chlorine is the catalyst for the ozone->oxygen transition that got freon ban
Re: (Score:3, Interesting)
If you use unpurified sea water you'll put a LOT of chlorine ions from sea salt into the ozone layer - near the equator where it's a big deal - and chlorine is the catalyst for the ozone->oxygen transition that got freon banned.
Salt has chloride ions, which are way more stable than molecular chlorine. Therefore, oxidizing chloride to chlorine would require energy input.
I actually spotted a possible fault in my argument (oxygen might be able to oxidize the chloride) but I'm not gonna tell you what it is.
Ok, doing some chem gives you this:
4Cl- + 4H+ + O2(g) <--> 2Cl2(g) + 2 H2O potential: -1.49V
Meaning that reaction isn't spontaneous, so it won't happen. Not sure what role sunl
Re: (Score:3, Funny)
It will never last on Fox.
Re:Space Quest (Score:4, Informative)
Unfortunately, most of the folks on here are probably too young to get the reference [dosspot.com], so, here's some text from the original boxes:
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Something doesn't seem to add up (Score:4, Interesting)
Something doesn't seem to add up. They've already indicated that slight modifications to trajectories can deteriorate an orbit, so some portion of the space junk caused by collisions must fail to remain in orbit. But they also say that collisions cause more junk, which causes more collisions, as though this were a never-ending cycle of feedback.
It seems as though there must be a threshold somewhere where the introduction of further space junk removes from orbit, on average, an equal amount of debris as it introduces. The farther past this threshold, the more likely that introducing debris will remove more than is introduced. There must be a point of equilibrium.
Take the following exaggerated scenario, for example. Let's say that by chance or plan, there is debris in orbit within every cubic meter at stable altitudes. (I am not a physicist, but this seems highly improbable statistically.) The introduction of a meteoroid through this debris field would almost certainly cause a significant chain-reaction with many affected objects acquiring unstable orbits leading to failure.
Not-to-scale pictures aside, I doubt we're anywhere near such a threshold -- even if we are reaching a point where our ability to avoid debris is insufficient to mitigate the danger. But surely it would be at least interesting, if not practically useful, to know this "saturation" point.
Or perhaps this is already known, and I am just unaware.
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Re: (Score:3, Informative)
It seems as though there must be a threshold somewhere where the introduction of further space junk removes from orbit, on average, an equal amount of debris as it introduces. The farther past this threshold, the more likely that introducing debris will remove more than is introduced. There must be a point of equilibrium.
Yes, but we are far from that point, and unprotected spacecraft will start turning into swiss cheese long before.
Re:Something doesn't seem to add up (Score:5, Informative)
Your imagined point of equilibrium is the point where there's nothing but space garbage, and if you shoot up more there'll be more garbage even though some of it falls back. I'm sure you remember Newton's law of conservation of momentum, now apply it to two oribiting satellites on almost similar trajectories crashing into each other, breaking into many pieces. Basicly, they'd become a spray of junk, some going up, some down, some faster, some slower. They'll spread out as if you fired a shotgun, catching up to some satellites while slowing down covering a greater and greater area to collide with others which will again behave the same way. It doesn't matter if 90 of 100 bits fall to earth if they take out >1,1 satellite each on average. It'll just escalate exponentially like a nuke going off, leaving a fine layer of bullets all over the stable orbit.
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Re:Something doesn't seem to add up (Score:5, Interesting)
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.
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Saturn (Score:5, Insightful)
Saturns rings would like a word with you. ;)
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