Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

The Space Garbage Scow, ala Cringely

Soulskill posted more than 4 years ago | from the dream-big dept.

Space 221

An anonymous reader writes "Robert X. Cringely once again educates and amuses with his take on how we could clean up the garbage that's in orbit around Earth. I cannot vouch for his math, but it makes sense to me. Quoting: 'We’d 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 net behind a little unmanned spacecraft, my idea would be to go past each piece of junk in such a way that it not only lodges permanently in the net, but that doing so adds kinetic energy (hitting at shallow angles to essentially tack like a sailboat off the debris). But wait, there’s more! You not only have to try to get energy from each encounter, it helps if — like in a game of billiards or pool — each encounter results in an effective ricochet sending the net in the proper trajectory for its next encounter. Rinse and repeat 18,000 times.'"

Sorry! There are no comments related to the filter you selected.

Make sure. (4, Insightful)

Z00L00K (682162) | more than 4 years ago | (#30106166)

That this doesn't break up any debris into more parts - or cause the "net" to break and provide additional pieces of junk circling the earth.

Re:Make sure. (2, Interesting)

yincrash (854885) | more than 4 years ago | (#30106396)

Mod parent up. In addition, tiny specks acting as micrometeorites are probably a much bigger problem than the bigger avoidable pieces. Hitting all that big junk together in a net at orbital speeds will probably result in even more micrometeorites.

Re:Make sure. (2, Informative)

gbjbaanb (229885) | more than 4 years ago | (#30106528)

I suppose you're catching stuff in a net travelling in the same direction as the junk so it'll be a gentle catch rather than a hard collision. That shouldn't create any more micro bits of shrapnel.

Re:Make sure. (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30106646)

I suppose you're catching stuff in a net travelling in the same direction as the junk so it'll be a gentle catch rather than a hard collision. That shouldn't create any more micro bits of shrapnel.

Maybe we can just put all the thug wannabe niggers on a rocketship and send it to the sun.

Just kidding.

Re:Make sure. (1)

Mr Otobor (1097177) | more than 4 years ago | (#30106592)

This also leads me to think that you'd need less of a 'net' and more of a 'sheet'. One would then wonder, depending on altitude and sheet size, when atmospheric drag becomes an issue.

I suppose you're strategy could be to release a large number of such contraptions to successively sweep/drag debris far enough into the atmosphere that they would quickly succumb to drag and burn up. Just hope you miss all the satellites... "Woops, sorry China/Russia, we swear that really was an accident..."

Wouldn't that be bad when it re-enters? (1)

Zakabog (603757) | more than 4 years ago | (#30106192)

Wouldn't it be bad catching all of the space debris in a giant net, when the net itself will eventually come back down to earth. Individual space junk coming out of orbit isn't as bad since it's not all falling in the same place and it's small enough to mostly burn up in the atmosphere, but if you've got this huge net there's a lot more junk to burn up with a much more localized crash site.

Plus this thing bouncing around like a billiard ball seems likely to catch something that isn't junk...

Re:Wouldn't that be bad when it re-enters? (2, Interesting)

fuzzyfuzzyfungus (1223518) | more than 4 years ago | (#30106278)

The risk of snagging one of the numerous live satellites would certainly be a problem. Re-entry, though, could be handled by picking an unloved chunk of ocean(hardly a limited resource) and just aiming for that.

Re:Wouldn't that be bad when it re-enters? (1)

hitmark (640295) | more than 4 years ago | (#30106316)

do not tell that to sea shepherd...

Re:Wouldn't that be bad when it re-enters? (3, Funny)

fuzzyfuzzyfungus (1223518) | more than 4 years ago | (#30106338)

We'll just tell them that it is our new orbital anti-whaling weapon...

Re:Wouldn't that be bad when it re-enters? (3, Informative)

wizardforce (1005805) | more than 4 years ago | (#30106330)

The problem with space junk is that there's thousands of piece of it flying around that can damage spacecraft, re-entry isn't really the problem. That's actually preferable to losing a few of your spacecraft to loose pieces of material in orbit.

Re:Wouldn't that be bad when it re-enters? (5, Interesting)

iksbob (947407) | more than 4 years ago | (#30106710)

Who says it needs to re-enter? If the bits of junk are all lodged in a larger net structure which behaves in a predictable manner, it could just be left up there as a sort of orbital junkyard. The proposed designs for a space elevator require a chunk of ballast to keep the tether taught... Why not a bunch of discarded booster shells and such, tacked together? It took a lot of energy to get that stuff up there... Why waste it?

Re:Wouldn't that be bad when it re-enters? (4, Insightful)

ThreeGigs (239452) | more than 4 years ago | (#30106896)

I'd mod you up if I had points. Apparently Cringely hasn't thought about how valuable a few hundred metric tons of refined materials would be in orbit. Instead he says "Nope, we have to gather the stuff and bring it back to Earth." He fails to realize that _someone_ would certainly pay for access to all of that material. He also fails to realize that a polar orbit intersecting an equatorial orbit will result in a relative velocity of about 10 kilometers per second, which equates to 50 megajoules per kilogram. Carbon nanotubes or not, nothing is going to withstand such a large amount of energy in such a small area, repeatedly, along with whatever centripetal forces are acquired from off-center hits from debris.

A visionary he might be, but a practical engineer he is definitely not.

Re:Wouldn't that be bad when it re-enters? (1)

Ironsides (739422) | more than 4 years ago | (#30106954)

50 megajoules per kilogram is only a problem if the net is not affected by the impact. Have the net take on some of the momentum of the impact and you can absorb a lot of the energy. You can also use an elyptical orbit to decreases the relative velocity.

gravity (-1)

Anonymous Coward | more than 4 years ago | (#30106202)

If this junk is junk, it has no means of correcting its path to stay in orbit. Sooner or later it will lose altitude, enter the atmosphere and burn up during descent. Or am I missing something?

Re:gravity (4, Insightful)

fuzzyfuzzyfungus (1223518) | more than 4 years ago | (#30106246)

Only the timescale. "Sooner or later" can be in the decades to centuries range, which is minimally useful for most of us now living.

Re:gravity (0)

Anonymous Coward | more than 4 years ago | (#30106348)

I don't know, maybe you are... how come all these planets including the Earth are still in the sun's orbit?

Re:gravity (0)

Anonymous Coward | more than 4 years ago | (#30106558)

I don't know, maybe you are... how come all these planets including the Earth are still in the sun's orbit?

Duh. God.

Cringeley Amuses (3, Insightful)

Philip K Dickhead (906971) | more than 4 years ago | (#30106226)

I thought they were just in the early stages of establishing a ring-world, in terrestrial orbit. Oh well...

There will of course, be no such mission, headed by NASA, or any other fraction of the Federal United States. That banana republic operates on such a scale, only when there is substantial room for contractor and supplier rip-off. If Cringeley can figure a way for DynaCor to pocket a billion on the side, instead of increasing fuel efficiency in spaceflight? It'd happen next year.

Cringely is an idiot. (-1)

stonecypher (118140) | more than 4 years ago | (#30106228)

It'd create a whole lot less pollution to just knock the garbage into the atmosphere with a mass driver than to burn up than to make nearly a hundred times as many manned space flights as have ever been made (276 as of end-May 2009) to go do janitorial duty. The energy cost of 18,000 space flights- 836,000 gallons per flight - would be enough to run the United States electrical grid at current draw for nearly six hundred years.

I'd tell Cringely not to quit his computer commentary job, but, well, he was just as bad at that.

Re:Cringely is an idiot. (5, Informative)

djmurdoch (306849) | more than 4 years ago | (#30106296)

You could try reading the summary next time. His proposal was for one flight, not 18000. I imagine his plan is still impractical for lots of reasons (you probably can't get enough impulse from each piece to approach the next one at a low enough speed, etc.), but it's still not as bad as your suggestion of 18000 manned space flights.

Re:Cringely is an idiot. (0)

Anonymous Coward | more than 4 years ago | (#30106300)

your and idiot not cringley. even TFS mentions collecting items in sequence, not a single launch for each object..

Re:Cringely is an idiot. (4, Interesting)

wizardforce (1005805) | more than 4 years ago | (#30106394)

A better idea might be to use the concept of induction to our advantage. Create a satellite that creates a several kilometer diameter magnetic field bubble and fly it through the debris at high velocity. THe debris is most likely conductive and would have a current induced in it causing a drag force against the janitorial satellite. The orbits that cause the most drag are ones that run counter to the craft so they'll probably be nudged into a lower orbit by the drag. The janitorial satellite will use solar power and a space tether to stay in its current orbit. Any satellites that need to stay up there and aren't considered debris can be tracked much more easily and you could just shut the EM field down upon close encounter with them.
The craft would use very little propellant and would probably work better than a net anyway. Just have a few craft like these flying around and acting like an immune system that kills off targets that are a danger to other craft.

Re:Cringely is an idiot. (2, Insightful)

Vellmont (569020) | more than 4 years ago | (#30106550)

That's not a bad idea. The real questions would be how much of a drag force could you create at a given distance? The junk is distributed in a cloud around the planet so encounters with junk could be hundreds of meters? Kilometers? Getting closer would require propellant. The field strength is limited by the amount of power you can generate, which ain't much from solar cells. The end effect is it may be completely infeasible because of scale. I wouldn't know how to work the numbers, but maybe someone else does.

Re:Cringely is an idiot. (1)

wizardforce (1005805) | more than 4 years ago | (#30106696)

It depends on how much debris you are deorbiting and how large the area you are using for solar power generation. If power is a problem, supplement the power generation with a nuclear battery or two and every time they ae exhausted, swap them out for fresh ones.

Re:Cringely is an idiot. (1)

maugle (1369813) | more than 4 years ago | (#30106930)

And as an added bonus, it'll accidentally take out all those pesky military satellites that don't officially exist!

Re:Cringely is an idiot. (1)

Baron_Yam (643147) | more than 4 years ago | (#30106992)

I like it. A giant magnet - suck up all the metal particles, never mind the big chunks! Give the nuclear power an ion engine and let it sweep clean whatever orbit you want.

In the end, you get a big(ger) metal ball, which you can keep in orbit as a useful mass, or drop on your chosen enemy.

Re:Cringely is an idiot. (2, Interesting)

zippthorne (748122) | more than 4 years ago | (#30106416)

Did you even read TFS?

He's not proposing 18,000 spaceflights manned or otherwise. He's proposing a gigantic billiards shot where all the balls are in motion, salvaging the motion of some of the balls to line up the next one and eventually encounter and sink all the balls in one shot.

Then he's got some weird ideas about orbital energy this "net" concept that seems tricky (although a sufficiently strong, ductile net would increase the target area for intercept and it doesn't matter if the net gets torn to shreds as long as the shreds stay attached), but the underlying idea is interesting, and it certainly doesn't need to be so tricky as to sink all the debris in only one flight with no inter-object maneuvering.

Re:Cringely is an idiot. (1)

jafiwam (310805) | more than 4 years ago | (#30106656)

He's still an idiot.

How much fuel is this thing going to have to hold to make tens of thousands of adjustments.

How much sensitivity does it have to have to actually get close to this stuff?

And, what if it screws up and gets tagged really hard. Orbital velocities of any object can smash just about any other object. What unobtanium is this thing going to be made of? A net? Are you fucking kidding? The stuff that can kill satellites is smaller than a grain of sand. If by "net" he means "bigass wall" then maybe. Plus, anything that is flexible (like a net) is going to be near impossible to move accurately. So it'll have to survive THOUSANDS of deployment and retraction cycles. They can't even get ONE FUCKING SOLAR PANEL to extend ONCE reliably for fucks sake.

It's a stupid idea, any one of the problems can make it a stupid idea, and there's dozens of problems with it.

They'd be MUCH better off just lifting lots of water and vaporizing it to produce drag on these objects so they fall in naturally on their own. If they do that from a NON orbital trajectory they might be able to catch a bunch of stuff easily.

"net"? (4, Insightful)

fuzzyfuzzyfungus (1223518) | more than 4 years ago | (#30106230)

Perhaps Cringely doesn't have a clear idea what sort of debris we are dealing with here

There are, certainly, some big chunks out there; but unpleasant enough(and far more numerous) are the little flecks of paint, bolts, and general fragments of this and that zipping around at bulletesque velocities.

Either this "net" will be made of very close-woven unobtanium, of the sort that we don't yet have, despite decades of interest in the personnel armor industry, or it will have to be a vast spongy particle trap, of the sort whose volume would be completely prohibitive for any available launch mechanism.

Re:"net"? (4, Insightful)

bmcage (785177) | more than 4 years ago | (#30106410)

Not only that, but does he realize how LARGE that space is? Can you imagine saying to somebody, take your yacht, and sail around the oceans picking up 18000 pieces that go around with vastly different speeds (and orbits)? Now do this in 3D instead.

Moreover, the delta v's involved are probably quite a lot larger than one would expect.

And as you say, the big pieces are tracked and show up on radar, it is the little pieces that hit unexpectedly.

Re:"net"? (1)

FlyingGuy (989135) | more than 4 years ago | (#30106782)

And don't forget the $200,000.00 ( USD ) bag of tools floating about, NASA ( one employee in particular ) would like to have it back!.

Re: tools (1)

chromatix (231528) | more than 4 years ago | (#30106892)

Funnily enough, that bag was released in LEO... and will therefore eventually decay of it's own accord. He'll have to be quick if he wants to snatch that up.

Re:"net"? (0)

Anonymous Coward | more than 4 years ago | (#30107034)

I'm surprised he wants to do it in one shot. Why have only one net? Why not 18* nets each scheduled to get 1,000* pieces?

I suspect (but cannot even come close to proving) that there is lots of this junk moving in relatively similar paths and speed that can be divided up into 18* groups with orbital commonality.

* Or whatever number works best

Cassini probe (Re:"net"?) (1)

Tablizer (95088) | more than 4 years ago | (#30107380)

I thought his idea is to use the momentum of Junk A to help shift into Junk B's orbit? The sequence of capture would be such that the smallest difference in orbit is selected for each item. It sort of reminds me of the Cassini Saturn probe: a moon's gravity is used to shift its orbit to fly by the next moon.

However, there's at least three problems. First, the mass of each junk item is not known well enough to rely on. Cassini had a little bit if this problem as nobody was sure of the some of the moons' mass until after the fly-by's. (Titan is used the most because it is the largest, and its mass was known from prior probes.) It's possible to make a rough guess based on brightness and/or diameter, but space junk may vary in density more than outer-planet moons. I'd say scrap the momentum-borrowing idea and just bring enough fuel, or ion engine solar panels, to shift orbit.

Second, computing Cassini's orbit to reduce fuel consumption was rather expensive. There's lots more space junk than Saturn moons (if you exclude the rings). Even without debris-momentum assist, the calculations are going to be tricky.

Finally as somebody else pointed out, the net would have a difficult time dealing with a potentially wide variety of velocities and shapes. It would take some fancy foot-work and/or strong net to pull that off. I wouldn't rate it as "impossible", but it will certainly tax the best engineering minds. A proof-of-concept trial run(s) may be the best way to start.

I would point out that the catcher wouldn't even have to come back. As long as the junk is collected in a single known location, it won't be a notable threat. A possible risk though is something coming by and tearing the net, releasing the hard-won bounty.

Re:"net"? (4, Interesting)

moosesocks (264553) | more than 4 years ago | (#30106418)

As long as you're traveling at the same speed and direction as the bulletlike flecks, you don't have to worry about damage. Given that space is a frictionless environment, it's actually fairly easy to accomplish this. We do it every time we dock with the ISS.

Cringley seems to be suggesting traveling slightly slower, as to absorb some kinetic energy in the impact, while preserving the integrity of the net. This sounds pretty cool in theory, although there are a few problems in practice, such as tracking all the tiny bits of debris, having enough fuel to maneuver, and ensuring that you don't get caught between two pieces of junk traveling in opposite directions.

It's a difficult problem to be sure, but I wouldn't write it off entirely.

As an alternate proposal, would it make sense to put huge blocks of aerogel (or a similar substance) into orbit? Junk that strikes the blocks would either get caught inside, or pass straight through (but lose some kinetic energy in the process, leading to its gradual orbital decay or capture). Aerogel itself has a low enough density that loose chunks of it would be relatively harmless to passing spacecraft.

Space is big... (0)

Anonymous Coward | more than 4 years ago | (#30106972)

Let's look at your alternate proposal. Say you can put huge blocks of aerogel in orbit. Huge blocks of a cubic kilometer (or a cubic mile, whatever). And say you can put a hundred of them in orbit every workday. That's about 20.000 cubic kilometer of aerogel in orbit per year.

Seems a lot, doesn't it? Well, it's nothing, considering the size of the space you're trying to clear. Imagine a ring with an inner width of 100km (low orbit) and an outer width if 30.000km. You'd need at least half such a ring to be able to sweep the area. That's 1,5 billion aerogel cubes. Even when you're launching one hundred of them every workday, it would take 75.000 years to get them up there.

It can't be done.

And that assumes that a kilometer of aerogel is actually able to stop and trap the debris. Which isn't likely anyway.


bussdriver (620565) | more than 4 years ago | (#30107086)

Slowing or absorbing into something that itself is not that harmful is a much better idea! Aerogel is a brilliant idea!

I was thinking more along the lines of some sort of gun shooting bullets of something harmless... aerogel would be perfect. similar complex issue of proper aiming and avoiding using up all the fuel.

Another idea would be to use some sort of ION drive or something to try to stay in orbit; power source would be a problem and I'm not sure there are enough ions out there to do enough to counter a movement. Too bad the amount of power needed for a really strong magnetic pulse makes that unlikely as well (although it would have more range than a big block of aerogel.) Much of the stuff up there is partially magnetic... doesn't take much to mess up an orbit.

Essentially this problem has been figured to be prohibitive long ago and it will take a lot more progress before we can realistically solve it; possibly many generations from now. I doubt that we'll ever get to the point where 1 nation can afford to clean while another intentionally dirties the sky (sooner or later there will be war in space-- we already leverage it heavily enough to provoke that now. )

Every velocity is super-bulletesque (1)

tjstork (137384) | more than 4 years ago | (#30106490)

Every velocity in space in orbit is super-bulletesque. It's the relative velocities that matter. I could catch the paint fleks with any old material, if, the relative velocities were reasonably close. Indeed, if you launched me out of a cannon next to a bullet fired out of a rifle, I'd almost be able to catch the bullet with no harm to myself. It's just the launching and the landing that would suck.

Re:Every velocity is super-bulletesque (0)

Anonymous Coward | more than 4 years ago | (#30106586)

Paint flecks aren't tracked, they're too small. All we know is that they're out there, flying in random directions. So how do you match their velocities?

Re:Every velocity is super-bulletesque (0)

Anonymous Coward | more than 4 years ago | (#30106648)

It is also super burlesque, what with all the talk of 'thrust,' 'explosions,' and 'entry.'

Re:"net"? (1)

Jeian (409916) | more than 4 years ago | (#30107140)

Perhaps Cringely doesn't have a clear idea what sort of debris we are dealing with here

He probably doesn't, but that's never stopped him opening his mouth before.

Quark! (2, Interesting)

Anonymous Coward | more than 4 years ago | (#30106238)

Anyone remember Quark, a space garbage scow show from the 70's? :D
It's nice to see it's time...

Re:Quark! (1)

OzPeter (195038) | more than 4 years ago | (#30106470)

Anyone remember Quark, a space garbage scow show from the 70's? :D It's nice to see it's time...

That was exactly what I thought of when I saw this .. ah the memories of seeing it on TV and the crushing blow when it was discontinued.

Re:Quark! (1)

rirugrat (255768) | more than 4 years ago | (#30106540)

QUARK! GARBAGE! Having Betty I and Betty II around made up for it...

you are the clone. no, you are the clone. (1)

SgtChaireBourne (457691) | more than 4 years ago | (#30106650)

Anyone remember Quark, a space garbage scow show from the 70's? :D It's nice to see it's time...

Quark [] was the first thing I thought of when I saw the heading. Life imitating art.

Re:Quark! (1)

squidfood (149212) | more than 4 years ago | (#30107216)

Anyone remember Quark, a space garbage scow show from the 70's? :D

We should re-task the Enterprise... it's nothing but a garbage scow anyway.

Why post this crap, Soulskill? (0, Insightful)

Anonymous Coward | more than 4 years ago | (#30106240)

Soulskill, why are you posting this crap from Cringely? Any article attached to that name is automatically shit.

I wish Roland Piquepaille had never died. At least his articles had some scientific basis to them, even if he was hated by many people here. Cringley articles, on the other hand, are bunk from top to bottom.

I have mod points. (0)

Anonymous Coward | more than 4 years ago | (#30106284)

I'd love to mod the article as (-1, Cringely doesn't understand space). Where's the button for that?

I cannot for his math, but it makes sense to me (0)

Anonymous Coward | more than 4 years ago | (#30106288)

The good news is, Cringely's article does not contain any math or physics. Without serious numbers to back it up, the idea is no more than a pipe dream. How do you catch a stone flying with a relative velocity of a few miles per second without getting blown to bits?

Sounds like..... (1)

Cinnamon Whirl (979637) | more than 4 years ago | (#30106336)

someones been playing Osmos [] too much.

orbital dynamics (0)

Anonymous Coward | more than 4 years ago | (#30106364)

among the other holes in this idea the biggest is that when in orbit an increase in velocity means an increase in altitude, to decrease your altitude you must either slow the space craft down or you need an elliptical orbit with an eccentricity approaching 1.

Not a big fan of "momentum," I see (0)

Tom Boz (1570397) | more than 4 years ago | (#30106370)

If you catch something stationary while you move, you won't increase your momentum; nor will you increase your kinetic energy. I don't care how much you want it to be akin to tacking into the wind, it won't work.

Re:Not a big fan of "momentum," I see (1)

TheLink (130905) | more than 4 years ago | (#30106452)

Only make some sort of sense if the summary had described the net as being in _front_ of the spacecraft, so that collisions increase the spacecraft's speed (which is in higher orbit and thus moving slower).

Even so, the net is more likely to cause stuff to break into smaller and harder to track pieces. And definitely bad if the net breaks...

Space junk's like any other problem (1)

SlappyBastard (961143) | more than 4 years ago | (#30106372)

Until something tragic happens because of a piece of space junk, no one will do anything.

Re:Space junk's like any other problem (1)

wagnerrp (1305589) | more than 4 years ago | (#30106780)

While there have been no 'tragic' accidents, there certainly have been dozens of satellites knocked offline due to collision with debris.

Metal (2, Interesting)

Idiomatick (976696) | more than 4 years ago | (#30106376)

Wouldn't something like a big ass electromagnet be useful? I mean, compared to a net... or something along the lines of giant flashlight (to push crap into earth)

Re:Metal (0)

Anonymous Coward | more than 4 years ago | (#30106632)

I see only one flaw with your idea: it does not include a frickin' big ass laser.

Re:Metal (1)

Sylos (1073710) | more than 4 years ago | (#30106808)

The real trick is a)space saving [magnets are/can be very heavy] and b)What about non-magnetic things? There are plenty of those up in space, so dealing with them is important as well.

Re:Metal (0)

Anonymous Coward | more than 4 years ago | (#30106920)

The Earth is a big electromagnet. And if you were able to create one powerful enough to change the velocities of every magnetic piece of space junk, the Earth's field would certainly alter your attitude and velocity as well. We use magnetic fields to adjust the attitude of spacecraft all the time.

[BALLMER] Magnet nets, magnet net, magnet nets... (0)

Anonymous Coward | more than 4 years ago | (#30106996)

magnet nets, magnet nets!

Magnet Nets, Magnet Nets, Magnet Nets, Magnet Nets, Magnet Nets![/BALLMER]

Interesting idea (1)

WindBourne (631190) | more than 4 years ago | (#30106386)

But I think that I would prefer a set of these, and dispense of them after a shorter time (burn it up or capture it for material studies). For starters, imagine accumulating a bunch of that junk together and then losing the ship. It could actually make things worst.

Also, this would be a good use for the tug concept. At some point, a tug will be useful for space. This could help push the concept.

Use Aerogels to slow objects w/o fragmentation (4, Interesting)

wisebabo (638845) | more than 4 years ago | (#30106402)

IF (and I know it is a big IF) it were possible to "manufacture" aerogels in space, this material could be ideal for capturing/de-orbiting small pieces of debris that would be too difficult/expensive to chase and capture the traditional way (via space tug or whatnot) but still poses a threat. Aerogels have already proven themselves as capable of capturing extremely fast (although tiny) particles moving at literally astronomical speeds without itself disintegrating. It was used precisely for this reason in both the "Stardust" and "Genesis" probes.

Now imagine instead of the small plates that were on these probes a very large slab tens or hundreds (thousands?) of meters on a side that would, over time, slowly intercept the smaller particles. Larger fragments would still go right through but might lose enough kinetic energy (without fragmenting and making the problem worse) so as to de-orbit themselves. The only thing that might make this remotely possible is the thought that the aerogel is so light (lighter than air) that a really huge piece could be put into orbit without spending billions in launch something heavy. Of course the only way to keep the launch volume reasonable is to MAKE it in space. Once in space, an ion engine would be required to counteract the atmospheric drag (and loss of kinetic energy from the impacts of the space debris).

By "manufacture" I mean the raw material (I guess it some sort of silicate compound) would have to be brought up from earth but since the resulting aerogel is 99.9% empty space, a little could go a long way. I understand that one way to produce it requires a super-critical liquid carbon-dioxide solution; obviously the CO2 would have to be recycled or better yet would be if a means of producing it directly in vacuum. Chemists, any ideas?

Re:Use Aerogels to slow objects w/o fragmentation (1)

zippthorne (748122) | more than 4 years ago | (#30106660)

Aerogel is pretty brittle, though. One can imagine flaking as a result of impact and no real net benefit debris-wise. I think something ductile would be a better choice. Like, say, steel foil, perhaps.

You want every impact to slow down the object enough that de-orbit occurs within months instead of years, and any detached pieces of the cloak should also have a similar profile. Only the intact cloak itself should be able to orbit for a time, until it is decided to de-orbit it, as well.

Re:Use Aerogels to slow objects w/o fragmentation (1)

wisebabo (638845) | more than 4 years ago | (#30106754)

Didn't know that about Aerogels. How about wrapping the whole thing in a (very) thin layer of "saran" wrap? (to non-Americans that's transparent plastic wrap). It'll keep the whole thing from fragmenting without (hopefully) adding too much to the weight.

Also, I'm hoping that little pieces of the Aerogel will be relatively "harmless" upon impact (is anything harmless at 25,000 mph)? Perhaps the "wrap" could be made non-transparent to something like UV while the Aerogel could be tailored to disintegrate upon prolonged exposure to UV. That way, any little fragments out of the "bag" will break up and be blown away on the solar wind.

Re:Use Aerogels to slow objects w/o fragmentation (1)

nurb432 (527695) | more than 4 years ago | (#30106690)

I don't believe an ion engine would be enough to keep anything stable that close to any planet. Their thrust is so low it would be like peeing in the ocean.

Re:Use Aerogels to slow objects w/o fragmentation (1)

wisebabo (638845) | more than 4 years ago | (#30106718)

I think the idea would be to put this Aerogel barge in a pretty high orbit. Anything in low orbit would naturally come down in a reasonably short time because of atmospheric drag.

Net? Use massive slabs of Aerogel instead (1)

MartinSchou (1360093) | more than 4 years ago | (#30106448)

And by massive I mean square kilometres and tens of meters thick.

Aerogel [] has been shown to be able to pick up even the smallest flecks of material for the Stardust [] project.

Since it's the smallest things that are the trickiest (huge bits are easily tracked), we need something that will not only absorb the energy of the impact, but also keep the debris in place. Thus, Aerogel is a good fit.

Re:Net? Use massive slabs of Aerogel instead (0)

Anonymous Coward | more than 4 years ago | (#30107064)

A tens of meters thick slab of aerogel won't stop (or slow in any measurable amount) a small bolt moving at orbital speed. Sure, you could maneuver the slab to it has a small speed difference but if you have to do that for every piece of debris you'd need way to much fuel. Can't be done.

Re:Net? Use massive slabs of Aerogel instead (1)

MartinSchou (1360093) | more than 4 years ago | (#30107190)

But through some unspoken magic a net can?

And orbital speeds are high, sure, but the slab is also moving at orbital speeds, which will reduce the impact speed significantly as well. And while it may not stop a bolt or bigger item on its own, there is nothing stopping you from placing thick solid metal back-stoppers every after few meters of Aerogel.

Then you end up with a gelatinous cube effect with the stopping power of several meters of solid steel.

Only issue is bringing down something that size. Aerogel is VERY light, but it's also an extremely good insulator and unless it's torn apart by the sheer wind forces, I doubt the metal inside it would suffer on the way down - big problem if it lands anywhere near anyone.

Why does Slashdot give voice to this moron? (1, Insightful)

Noose For A Neck (610324) | more than 4 years ago | (#30106460)

Does Cringely have some kind of seedy business relationship with Slashdot's parent company?

Re:Why does Slashdot give voice to this moron? (2, Insightful)

Macrat (638047) | more than 4 years ago | (#30106572)

This is part of Slashdot's comedy posting allotment.

Gel or Foam? (1)

JensR (12975) | more than 4 years ago | (#30106496)

What about some gel block, or even better some kind of foam?

It would be like... (0)

Anonymous Coward | more than 4 years ago | (#30106750)

playing Katamari Damacy in Space!

Re:It would be like... (1)

JensR (12975) | more than 4 years ago | (#30106842)

In a sense, yes. From what I understand the problem with space debris are the small size and the high kinetic energy. If you've got everything in a big lump it should be easier to de-orbit stuff and get it to burn up in the atmosphere.

One other thing (1)

WindBourne (631190) | more than 4 years ago | (#30106500)

It makes sense to capture and lose the small pieces. BUT, the large ones are lots of material in space that took a lot of fuel to get there. That would be a shame to lose those if they are together. Seems like we can push those into a higher orbit out of the way and then use them in the future.

Here's an idea (0)

Anonymous Coward | more than 4 years ago | (#30106526)

We can send convicts with bright orange space suits into space. Give each one a trash stick and a burlap bag. For obvious reasons, there's no need for shackles and chains.

Conservation of energy/momentum (1)

hcg50a (690062) | more than 4 years ago | (#30106554)

...means the net will lose speed every time it captures some junk. The author needs to take high school physics again.

Tacking on a sailboat works because the wind is blowing on the sail, adding energy to the whole craft.

Scooping stuff in a net is just an inelastic collision. The momentum gain of the junk will equal the momentum loss of the net. The net's orbit will decay as it captures more and more junk.

Re:Conservation of energy/momentum (3, Informative)

TheRaven64 (641858) | more than 4 years ago | (#30106664)

It's not quite that simple. If the orbit is elliptical then two orbits can intercept even though they have different energy level (average heights). If the two objects in the two orbits join then the one in the higher orbit will lose energy and the one in the lower orbit will gain energy (which corresponds to average height). The resulting object will have the same momentum as the vector sum of the momentum of the two objects, which will give it a new orbit. If you start in a low and highly eccentric orbit, after a number of such collisions you may end up in high and relatively circular orbit (or not, depending on the collisions). Cringely is broadly right that it is probably possible to design an orbit such that the net eventually collects everything. Unfortunately, 'eventually' in this case can mean several million years, possibly longer.

Re:Conservation of energy/momentum (1)

CrimsonAvenger (580665) | more than 4 years ago | (#30106708)

...means the net will lose speed every time it captures some junk. The author needs to take high school physics again.

You might want to consider a good orbital mechanics course yourself. If, as an example, I am travelling in an elliptical orbit with apogee at, say, 500 km and perigee at 300km altitude, and I hit a bolt in a circular orbit at 500 km, then I have just run into something that is going FASTER than me.

Which means that I'll speed up slightly, raising the perigee of my orbit.

The assumption that the net is moving slower than whatever it captures is a ludicrously silly one in space, where pretty much everything is moving literally faster than a speeding bullet. It's just a matter of using the right orbit to catch any particular object.

Speed of debris is 25,000 ft per second. (1)

lkcl (517947) | more than 4 years ago | (#30106568)

Particles the size of a grain of sand - assume 1 gram. Speed: 8333 metres per second. Kinetic Energy Formula: 0.5 * mass * velocity * velocity.

Kinetic Energy of grain of sand: 34,719 joules.

Small car travelling at 30mph, mass 1000kg. Speed: 13 metres per second.

Kinetic Energy of car: 84,500 joules.

Area to which impact of grain of sand occurs: assume 1mm square.

Kinetic Energy per square metre when grain impacts: 34 billion Joules/Sqm.

Area to which impact of car occurs at 30mph: assume 1 sq m.

Kinetic Energy per square metre when car impacts: 84 thousand Joules/Sqm.

this is why, if a dust particle the size of a grain of sand hits a spacecraft it would leave a micro hole on one side, vapourise and turn to plasma, cutting its way through absolutely everything in its path in a geometrically predictable and expanding pattern. net result is a gaping cone of missing spacecraft on the other side of the dot, significant additional debris, and some dead astronauts.

and that's just the dust particles.

Materials science is simply not up to the job of dealing with this kind of energy impact, which is why, instead, NASA tracks several tens of thousands of objects including an Astronaut's boot, and makes sure that everything that goes up stays well clear.

Re:Speed of debris is 25,000 ft per second. (1)

zippthorne (748122) | more than 4 years ago | (#30106716)

You don't need to hit it head-on, and you don't need to bleed all of the orbital energy to put the debris chunk into a rapidly decaying orbit.

Presuming that there is only a countable number of objects (a few thousand, tens of thousand, even a million), it's much more reasonable to approach "just enough" to knock them into a month-long freefall instead of a decades long, one at a time. A computational nightmare, perhaps, and definitely extremely tricky to line up the right piece of debris without putting yourself in the retrograde path of the wrong piece, but it's not going to get easier as we accumulate more trash.

Re:Speed of debris is 25,000 ft per second. (1)

Fleetie (603229) | more than 4 years ago | (#30106732)

A grain of sand weighing 1 gram? You're an idiot.

Re:Speed of debris is 25,000 ft per second. (1)

lkcl (517947) | more than 4 years ago | (#30107366)

fine: who gives a fuck. make it 0.01 grams. the kinetic energy per metre squared is 340 million joules per metre squared instead of 34 billion.

Re:Speed of debris is 25,000 ft per second. (0)

Anonymous Coward | more than 4 years ago | (#30106790)

Your assumptions are wrong. Assuming a cubic particle, you have a particle density of 1 kg/cm^3, which is far higher than anything on this planet (Osmium only has a density of .022 kg/cm^3). To get a particle of that density, you would need to mine the core of a reasonably dense star.

Or you could reduce the energy of the particle by 2-3 orders of magnitude. Still a very energetic impact, though.

Gain kinetic energy? (2, Interesting)

caseih (160668) | more than 4 years ago | (#30106580)

To drop from a higher altitude to a lower altitude you have to lose kinetic energy, not gain it. Furthermore, everything is not traveling in the same direction. There are many different orbits and junk is in all sorts of them. So some junk you'll never "net" since it's traveling in the same direction as the dejunker, and other junk is traveling exactly opposite and will slam into the net with twice the velocity of the denetter's current orbital velocity. Furthermore if the junk's orbit is 90 degrees to the dejunker, it will never be caught either. Even if the orbital paths crossed, it would probably just destroy or damage the dejunker satellite (paint fleck or rachet wrench).

So it wouldn't seem that his idea stands the common sense test (or physics for that matter). But this is just slashdot and I am not an orbital-mechanics expert. I failed that class at the starfleet academy (or was that temporal mechanics).

Re:Gain kinetic energy? (1)

jafiwam (310805) | more than 4 years ago | (#30106726)

Orbits are a combination of potential and kinetic energy. Depending on what orbit you are in, and what phase of the orbit you are in at the time those numbers will flip around being the predominant one.

So, depending on what you are doing, where you are now, and where you want to go you may have to do some counter-intuitive moves.

Danger! Danger! (1)

Dachannien (617929) | more than 4 years ago | (#30106622)

Unfortunately, the operation of a space garbage scow is fraught with danger [] .

Quark (1)

nurb432 (527695) | more than 4 years ago | (#30106680)

Need i say more?

Re:Quark (0)

Anonymous Coward | more than 4 years ago | (#30107154)

Need i say more?

As far as obligatory entertainment references whenever an article on space junk management shows up, yes, you need to say more:

Planetes []

Good way to use Bigelow (1)

WindBourne (631190) | more than 4 years ago | (#30106704)

Bigelow has a small line to build Kevlar material for their space stations. It is suppose to handle 17000 mph pieces. Seems to me that BA might want to get in on this if funds were to be done. At the very least, it helps gets their line started with building items.

science fair-y tale (1)

JackSpratts (660957) | more than 4 years ago | (#30106744)

cringely sounds more and more like a clever junior high school student. nothing wrong with that, if you're in 8th grade. but i mean seriously, the volume of 3-d orbital space determines among other things the energy and time required to sweep it "clean." be almost faster just to wait for the junk to re-enter. cheaper and cleaner certainly.

Why a net? There's no resistance in space! (1)

los furtive (232491) | more than 4 years ago | (#30106836)

Why a net? There's no resistance in space and no medium that needs to pass through the net! Make it a big metal cup like the back of a dump truck. Drawback would be increased payload for launch, but it helps remove a lot of the risks others are describing such as the net breaking or contents of the net breaking up into smaller pieces.

Playing billiards (1)

chromatix (231528) | more than 4 years ago | (#30106942)

Unfortunately Cringely has overlooked the principle of conservation of momentum.

Once each piece of junk lodges permanently in the net - assuming for the moment that the net is a good solution - the whole ensemble will by definition have the total momentum vector that the spacecraft+junk had beforehand. No amount of clever angling will help that.

Now, if he instead said that he was going to bounce off each piece of junk so that the junk was sent into the atmosphere and the spacecraft was also redirected usefully, then that would have been more plausible - except of course that he would then need to make the spacecraft itself pretty damn robust.

No, I'm much more inclined to consider small drones which can drift around with a little ion drive and attach to a few bits of junk each (at near-zero dV), and then deorbit themselves.

Asteroid Deflection (1)

hardihoot (1044510) | more than 4 years ago | (#30106998)

Doesn't anyone realize that spacejunk is our only hope of deflecting the killer asteroid when it comes? Think of the children!

Garbage scow? Nay, space sharks! (1)

macraig (621737) | more than 4 years ago | (#30107002)

I say we launch sharks with frikkin' frakkin' lasers to vaporize the stuff. Who cares if they'd conserve energy and momentum, they're sharks and they fry things!

anime: Planetes (0)

Anonymous Coward | more than 4 years ago | (#30107022)

Recommend people check out the series "Planetes" on this topic:

Go back, start over. Way back. (1)

SEWilco (27983) | more than 4 years ago | (#30107048)

He does need to apply a little math there. Dragging a net behind might happen due to (weak) atmospheric friction, but you're not going to sneak up behind debris and gently catch it in the net. Something in a lower orbit is moving faster relative to you, so the debris will come from 'behind'.

Also, you're going to be waving a huge net around and hope to only get close enough to things that are traveling at speeds which are only slightly different. Somehow you have to not catch working equipment, and not get smacked by something in a path at 90 or 180 degrees. That's worse than praying for a magical 18,000 carom path.

When you do catch something, it's not going hit right in the center of gravity so your whole contraption goes spinning. The first time that happens, your net might close around what might be in it. But it won't stop without a lot of fuel. And if you don't stop it yet somehow manage to intercept something else the something else will hit the outside of your net purse and send it spinning in another direction. If you do stop the spinning and reopen the net, the movement of opening will push your catch out and away.

That's assuming you can actually catch anything. It's more likely that you'll blunder into the path of things moving in the wrong direction. Then the debris will be increased by bits of stuff that got hit, followed shortly by whatever is torn off by the stresses of the net trying to head off in another direction (assuming your net got hit and not your garbage trawler).

Go look up the designs which others have done. Nets which are intended to vaporize or slow debris, electromagnetic drives, including deorbiters on new satellites.

And, no, don't think Quark. Think Planetes.

its the travelling salesman problem (1)

circletimessquare (444983) | more than 4 years ago | (#30107094)

with 18,000 destinations, all of them moving, and each with a different angle, trajectory, spin mass, etc... []

so while the idea as a real world solution is obviously impractical, its a great way to exercise computer scientist minds to dizzying distraction

He doesn't understand orbital mechanics (1)

argent (18001) | more than 4 years ago | (#30107168)

"It won't always be possible, of course, to gain energy from each encounter, but that's why we start in a higher orbit, so as energy is inevitably lost it can be replenished by moving to a lower orbit."

Changing to a lower orbit will increase velocity, yes, so in a sense you're trading off potential and kinetic energy... but in the sense that matters... maintaining the ability to change your orbit... it doesn't matter if you go up or down, it matters only that you are changing your orbit. Any change in orbit requires you to shed reaction mass. And it's the mass that you need to conserve, not any fuzzily defined energy.

But wait, there is one possible solution, you could use conductive tethers. You could use them to raise your orbit by pumping current through them, or lower your orbit by running the current from them through a load, like a generator. You'd probably NOT want a polar orbit for this trick. And you'd need lots of big heavy solar panels to provide the power. Or maybe a radiothermal generator. No, that'll never fly.

The big problem, though, is that the operational lifetime of the device has to be large enough that it results in a net reduction in trash. And it's deliberately colliding with junk? Eventually it's going to mess up and hit something with the wrong part of the device, particularly if it's using tethers for maneuvering, and now you'll need to have another net handy to collect IT as well as the trash it collected.

Would it be possible.. (1)

Nidi62 (1525137) | more than 4 years ago | (#30107330)

Would it be possible to use that same gel-type stuff they used to collect tail material from that one comet? Use it almost like ballistic gel or the rubber backstop of an indoor pistol range?
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?