Using Lasers and Water Guns To Clean Space Debris 267
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."
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.
Re:Water is heavy (Score:5, Funny)
Damn! Shut up already! The average moron will totally believe your rain concept.
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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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
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The water would eventually re-enter the atmosphere, where it would burn up.
Re:Water is heavy (Score:5, Funny)
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.
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.
Re:Water is heavy (Score:5, Funny)
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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?
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He doesn't see any problem with creating sprays of water droplets that will freeze into clouds of bits of ice traveling at thousands of miles per hour? Granted they will sublimate over time but until that happens you have a bit of a problem.
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Re:Water is heavy and it freezes (Score:2)
Why wasn't it blindingly obvious to the proposer of this scheme that you can't clear space debris by sending more up there?
(it sounds like the sort of daft logic that unscrupulous financiers use to persuade the gullible that you can clear your debts by consolidating your loans - duh!)
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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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!)?
That's a good point. Plus how will the water stay liquid? And what if it doesn't come out as a spray. I bet it would suck to get hit with a big frozen ice block in orbit.
The US should fix this problem the way they fix everything else: Hire a bunch of illegal immigrants or people from a 3rd world country to go up there and pick all the junk out of orbit!
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It will freeze, but sublimation will take care of the problem.
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Re:Water is heavy (Score:4, Insightful)
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Bonus: if we just suck in a bunch of seawater, put it on a rocket, and shoot it at debris to clean it up, there's a possibility that we will accidentally shoot a scuba diver out into space. Which would tickle my sick sense of humor at least.
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Good (Score:2)
http://science.slashdot.org/article.pl?sid=08/09/05/1231228
Ok, now serious, really (Score:2, Interesting)
Someone writes on slashdot days ago about the interesting idea of put a "shield" on space made with a plastic soft container, for example a large plastic bag. fills then with water, the water frozens and you get a good ice shield to put on path of debris. once the shield caugth the debris then can send back to Earth on a planned reentry or ejected to deep space
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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Does anyone have an idea how quickly frozen water sublimates in a vacuum?
It's possible that any ice chunks would turn to water vapor fast enough to not pose a problem for other orbiting objects.
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The plastic bag is just to the ice not drift away when inpacted (and to control shape on solidification).
Slow down there, son, your error rate is climbing into the unacceptable range.
A plastic bag can't control the shape of ice much when it solidifies. You can try the experiment at home in your own freezer if you don't believe me. Now imagine trying that in an environment where all your water wants to boil as soon as you get it out of the container.
And i are thinking on a big ice shield, a one big enougth to not "explode" on every debris inpact.
Is you? It doesn't work like that, though, because an ice crystal can't distribute the force of the impact very efficiently. The impactors are going to break loose
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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Zapping: This isn't what you think. The idea is to ablate one side of the debris so it de-orbits, rather than making it into smaller pieces.
Collecting: Probably not easy.
Adding atmosphere: interesting point about de-orbiting bad things, but the de-orbiting is going to happen anyway if these things are in a low enough orbit to be a debris problem. Adding density to space will just accelerate the deorbit.
Hmmm. I think I smell a sitcom in this... (Score:2)
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team of orbiting garbage collectors
Damn, the recession must be hitting the rocket scientists REALLY hard for them to resort to garbage collection.
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It will never last on Fox.
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?
Mass? (Score:2)
They might have mass but I think you miss the point. Debris in orbit presents a hazard to spacecraft. A small paint chip left a small crater in the windshield of the space shuttle. Debris can be as small as a paint chip but its mass is enormous compared to subatomic particles. The mass of subatomic particles is just not big enough to present a collision hazard to spacecraft. Enough of them might cause additional drag which might cause their orbits to degrade prematurely. Note: I am not talking about t
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A strong enough magnetic field might be enough to warp the metal stuff into an orbit that burns up in the atmosphere. Or maybe it could be designed to collect the fragments into large blocks that could be sent down individually.
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Could you use an ion beam to give these materials a net charge?
Any object with a net charge would experience drag from the Earth's magnetic field, speeding it's eventual demise in the Earth's atmosphere.
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Not only would lofting water into space be a colossal waste of energy and water, . . .
Well, a colossal waste of energy to be sure. But, as wastes of water go, a few tens or hundreds of tonnes is, as they say, not even a drop in the bucket. That's on the order of a 50-meter swimming pool or three, or the annual water usage of a few dozen people.
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I intended for the ablation to provide enough momentum change for the particle to deorbit, not to lase it enough to eliminate it.
I would think your band of higher density would be dangerous, given that tiny particles of water have a nasty habit of sticking together and forming larger chunks (like a comet, say). Even by themselves, how much damage would a tiny retrograde water crystal do hitting a prograde satellite?
Without knowing the drag function on water vapor, it'd be hard to say how long it would sta
genius at work (Score:3, Insightful)
Wow. Just, wow.
Re:genius at work (Score:4, Funny)
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Water.... (Score:2)
One cubic foot of water is around 60 lbs. The is $600,000 per cubic foot of water. Not very cost effective. And my numbers are old and off the cuff. It could be far more expensive now.
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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Not without help from Google.
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The metric system makes life too easy.
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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
Should we really be firing our water into space? (Score:2)
Seems like a bad idea.
PlanetES (Score:5, Interesting)
Thank you for being the token PlanetES post (Score:2, Insightful)
This is roughly akin to mentioning "24" in any article on Slashdot about terrorism.
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.
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There's two significant problems with just about any sort of physical collection of space junk. One is the relative velocities of all the crap in orbit. This stuff is moving really fast, so whatever mechanism you're using to catch it is going to have to absorb a lot of energy without being destroyed. There are some techniques that have been developed to protect spacecraft and even collect fast moving pieces
(aerogels, a series of thin metal plates to dissipate impact energy), but those types of shielding are
Just keep launching junk into orbit (Score:3, Funny)
Frickin' lasers? (Score:2)
These are all very nice ideas, but first they'd have to develop spacesuits for the sharks.
Which puts us one step closer to landsharks.
Re:Frickin' lasers? (Score:5, Funny)
Which puts us one step closer to landsharks.
*knockknock* "Plumber!"
Only one way to be sure its clean (Score:2)
Call Adam Quark.
New NASA revenue stream . . . (Score:2, Insightful)
AEROGELS (I guess spacegels) (Score:2)
If aerogels can be made in space (without the need for the heavy supercritical fluid needed to make it on earth or if there is some way to recycle the fluid) you could cheaply launch very large volumes of a substance that would have the ability to absorb momentum from colliding objects. This would either result in the object being embedded in the aerogel (if it was small relative to the aerogel) or the object would punch through it but still end up being decelerated (if the object was large but still small
Space Quest (Score:2)
Where's Roger Wilco when you need him...
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:
Energy (Score:2, Interesting)
Do the math, fellas (Score:2)
The economics of this plan are kinda awful.
For instance, sending water into space is mighty hard on the wallet. Figure on about $8,000 per pound to send it into a retrograde orbit. And you'd need to send up, oh, let's say a trillion pounds to seed the orbits with a 0.0000001% density of ice. About 10^11 cubic kilometers, 10^26 cc's, 10^18 grams, 10^ 15 kilos, 2.2x10^15 pounds, 1.8x10^19 dollars. That's a 18 billion billion dollars.
And using lasers is no picnic either. You'd want to deliver many kilowatts pe
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.
Idiots.... (Score:2)
Do we not have a space station up there, might it not need extra parts of wires or glass or metal, could we not recycle by going to get them using a shuttle and bringing them back to the station to reuse the parts, or even have a smelt up there where we could burn up the metal to create new shapes needed for repairs...etc.
Come on people...let's get with the program...recycling is good and will waste a lot less money creating lasers or water guns or robotic garbage collectors!!!
I really hope NASA and the lik
But, but... (Score:2)
Andy Griffith is way too old to be heading out into space again!
I trained for this in college (Score:5, Funny)
OS/400? VMS? TSO/ISPF? UNIX? (Score:3, Funny)
World wide water shortage? Hardly (Score:2)
Potable water is mostly at its limits in many areas of the world because of politics, science has had the answer for along time and there has been ample money available, where it is allowed.
Plus politics is a great way of creating shortages where none existed. I live the perfect example of this, where it was decided years ago in some Federal Court that some mussels and some barges needed the water more than humans for who the damn was created form decades ago.
I won't even get into how much people waste in
Look on the bright side (Score:2)
I won't even get into how much people waste in the states watering their lawns, I swear some of my neighbors could fill a pool a week.
You must live in a good neighbourhood. Some of my neighbours could fill a pool a week with their empty beer cans.
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I won't even get into how much people waste in the states watering their lawns, I swear some of my neighbors could fill a pool a week.
Are all plants a waste, or just the fast growing ones? (it is a rhetorical Q, but I don't know a answer) My grass (6' by 50') I planted because without it I would have to funnel all the water from the roof to the sewer (also adding gutters is forbidden by home owners), for treatment. Since the grass filters it, disperses it, and prevent erosion, I just have enough to do that (but still needs watered) Regardless I think the grass provides enough benefit (except in really arid places, or low density popula
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Send up seawater. Don't think there's gonna be a shortage of that in many million years. Hell, everyone keeps complaining about Venice slowly sinking into the rising ocean.
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
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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
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Send up seawater. Don't think there's gonna be a shortage of that in many million years. Hell, everyone keeps complaining about Venice slowly sinking into the rising ocean.
Yea and the huge flood that global warming is sure to incur. It might be a good idea to start bailing the water out now.
A little OT but I wonder if this came about during the same brainstorming session that is trying to figure out how to accidentally push space junk into China's upcoming space stations.
OMG we should, like, totally send up ice from the south pole!
</ohgodpleasedon'tanybodytakemeseriously>
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We are already approaching a world wide water shortage are we not?
No, we're not. Take a look at the earth from space....75% water. WTF?
Do you mean Drinkable water? Why the fuck would we send bottled water to space when salt water or mud puddle water would work just as well?
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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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.
Then why aren't the astronauts eating lobster tail and caviar?
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Why the fuck would we send bottled water to space when salt water or mud puddle water would work just as well
Well, it would be nice to have some sort of legitimate use for all that "sparkling" bottled water you see in the shops.
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Re:Obrigatory (Score:5, Funny)
> Sharks can fly to space?
That's what the water is for.
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Aside from the obvious ( Do not look at nuclear explosion with remaining eye), you also get a nice EMP effect from nukes.
This would effectively eliminate the same satellites you are trying to protect.
Add to that, the problem of other countries not liking the idea of an orbital nuke launch, protests against nuclear weapons, political implications, making utility purpose for Nukes, etc.
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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.
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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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.
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.
Saturn (Score:5, Insightful)
Saturns rings would like a word with you. ;)
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That was the first thing I thought of. I'm not sure if paint chips will pick up a charge, as others have pointed out.
Sam Gunn is a great character. Kind of like a cross between Michael Miliken and MacGuyver, but in space.