coondoggie writes "Some work has begun on tracking and detecting the overabundance of space junk which has become a growing priority as all manner of satellites, rockets and possible commercial space shots are promised in the coming few years. Today Northrop Grumman said it grabbed $30 million from the US Air Force to start developing the first phase of a global space surveillance ground radar system. The new S-Band Space Fence is part of the Department of Defense's effort to detect and track what are known as resident space objects (RSO), consisting of thousands of pieces of space debris as well as commercial and military satellites. The new Space Fence will replace the current VHF Air Force Space Surveillance System built in 1961."
by Anonymous Coward
on Wednesday July 15, @10:54PM (#28712273)
We have a system called NaviSys IV. The project has been going on since the '70s and originally involved large UHF and SHF antennas on balloons/blimps. That idea did not work out well as constant monitoring eventually was needed for tracking spy satellites and movements (e.g. attitude correction), and we went with a ground-based operation either running at L or S-band, but I can't remember which.
I used to be a technician for the tracking consoles back in the '80s before everything became fully automated. Everything then was mundane as it is now, and the old technology worked very well. Supposedly objects about a half metre were tracked, but that was "classified" information at the time.
It would appear to me that an American corporation is just trying to get yet another contract to do the same thing that they have been doing for years. VHF/UHF has some disadvantages, but the system in place is (or at least was) similar to the UK's. It looks like yet another money grab by the contractors to replace something that is fully functional and could operate for a generation or two at a nominal cost. What, after all, is a mere $30 million USD, though?
Everything then was mundane as it is now, and the old technology worked very well. Supposedly objects about a half metre were tracked, but that was "classified" information at the time.
Did you actually read the article? The current system tracks objects 4 inches and larger in diameter. The new system will track objects as small as 1/2 inch in diameter.
FTA:
"the United States Space Surveillance Network, managed by U.S. Strategic Command, is tracking more than 19,000 objects in orbit about the Earth, of which approximately 95 percent represent some form of debris. However, these are only the larger pieces of space debris, typically four inches or more in diameter. The number of debris as
A company didn't just dream up an idea and then the government bought it. Acquisitions in the US Department of Defense don't operate that way. The services (US Army, Air Force, whoever) had a need for the capability, or to replace a system that wasn't sustainable (for whatever reason) and went through an analysis of what needed to be done and how current systems can or can't fulfill that role. When there's no system and the needs are there, then the DoD moves forward with a Request for Proposal. The eco
Launch water. You don't need to put the water into orbit, just release it in the path of whatever debris you want to deorbit and let your launcher fall back to earth. The debris loses velocity as it passes through a cloud of H2O molecules and slows down enough to re-enter the atmosphere. Sine you don't need the delta-v, the launches are fairly cheap, at least as long as we're at low altitudes.
One problem with that - it's *cold* up there. The water would probably freeze the instant you launched it at something. Now, you could always put a heater up there to keep the water warm, but that results in more space junk.
Me, I think a giant space vacuum cleaner would do the job.. we just need to borrow one from the folk at Space Balls.
Its not cold up there. Its in a vacuum. Vacuum doesn't have a temperature.
But liquid water released into a vacuum will partly sublimate and partly freeze. Then the frozen water will slowly sublimate as photons from the sun hit it. If you can disperse the water fast enough in vacuum it should sublimate fast because of the huge surface area.
A different liquid (like Nitrogen) may do a better job.
Thats true. Low earth orbit is a low quality vacuum at a high temperature. Because of the low density photons from the sun can pump it up to very high temperatures. This study suggests 700 to 1100 kelvin at 240 km altitude [defence.gov.au].
That would not change the mass, something flying through this cloud would still be slowed down.
But I think these tiny molecules would quickly be pushed away by radiation pressure and maybe by whatever other part of the solar wind that makes it through earths magnetic field. UV radiation also ionizes, then you have charged molecules/atoms which allows one more force to interact with them. Oh, and the boiling process would of course accelerate the particles in the first place, so a triple no-go!
I definitely agree with the general idea but I am concerned that not enough water would sublimate during a suborbital lob. Ideally you want your payload to be liquid or solid at launch to save on structure in the launcher. You could pack it with an explosive but that got me thinking about this coke bottle which was in the back of my car rolling from side to side for hours until I cracked the seal and got myself covered with sticky muck.
So maybe we need a mixture of CO2 and H2O at moderate pressure to get
IT's kind of expensive to get water into space. If you think about it, the space shuttle can hold a payload of about 50k lbs. That would be roughly 5,995 gallons of water without any containment structure. Now the containers would probably have to consume 1/3 or more of that capacity because not only do you need to contain it, you need to make sure the containers will withstand the G-forces necessary for launch into orbit and because of that much water.
To give you an idea of how much water 5,995 gallons is,
Its expensive to get water into orbit. It is much less expensive to get it directly into space so it falls straight back. You don't want it to be in orbit anyway. You just want a cloud which the debris goes through.
IT's kind of expensive to get water into space. [...] Another problem with water floating in space, how would we keep it selective in only de-orbiting what is junk and not what is in use?
MichaelSmith [slashdot.org] has already provided a general answer, but here's some numbers to go with it.
"Look," Musk says, scribbling equations on a notepad, "the energy increases with the square of the velocity. To go 60 miles into suborbital space, like Rutan and the X-Prize, you need to travel at Mach 3. The square of that is 9. But to get to orbit, you need to go Mach 25, and the square of that is 625. So you're looking at something that takes 60 to 70 times more energy. And then, to come back, you need to unwind that energy in a meteoric fireball, and if there's one violation of integrity, you're toast."
Of course, we don't care as much about the return trip. We don't care at all about the water, and if we want to reuse the carrier, it's falling like SpaceShip One, not a space shuttle.
That is how satellite killer missles work. Unfortunately, any solution to this problem must take into account the fact that there are many thousands of pieces of space junk big enough to track.
In fact, it doesn't need to be water; anything will do. The most efficient way to do it in future might even be to build a rail gun and launch a small (few tens of kilograms) projectile with a timed explosive. Projectile gets out of the atmosphere, projectile explodes into a cloud of debris, target hits debris and slows down, debris falls back to earth (it's on a straight up-and-down trajectory, not an orbital path) and burns up on re-entry because it's now the consistency of sand.
If you are going to target specific Junk with this idea why bother sending up water when you can use a LOX/Hydrogen propellant? Simply Launch your vehicle through your targets upcoming orbit and the contrail can do the rest. Given that there is no requirement for a payload this gives some scope to actually de-orbit & re-use the vehicle parts.
I was thinking "recover and recycle the stuff". I mean really, it wasn't that cheap to build them and put them up there, I am sure that some of the stuff floating around up there is still worth quite a bit of money. Maybe if it could be done via remote control we could even save the expenses associated with sending people into space to do the job.
This reminds me of Planetes, a TV anime series by NHK (the Japanese equivalent of PBS/BBC) about the consequences of runaway space garbage in the near future (2072) of humanity. It's an interesting story, and it gets major extra points from me for being remarkably realistic.
The real reason for this space fense is to keep the illegal aliens out. It's just not politically correct to discriminate against the Earth-challenged, so they have to come up with some other justification.
Didn't Arthur C. Clark or someone theorize that at some point in any space-faring civilization, they would lose (at least temporarily) the ability to return to space due to the density of debris orbiting their planet?
Let's just send a giant magnet up and start over...
Giant magnets are hard to come by these days. It used to be, the earth naturally contained many thousands of millions of tons of giant magnets. Even amateurs long ago could dig them up and get themselves into all sorts of unexpected trouble. Now, things are different. We've devastated our natural resources, and man-made electromagnets just don't work the same way. In fact, that's the primary reason you don't see many giants loping around the hills wavi
There's an award winning anime/manga series called Planetes [wikipedia.org] that deals with this very problem. It's about the people whose job it will be to dispose of the detected debris (usually by burning it via atmospheric reentry or through salvage) before it collides into something.
In a few months we'll have Large Hadron Collider back online. The black holes are sure to clean up this mess once they've collected enough planetary mass.
For anyone else who works on satellite RF systems.. 768KW = 89dBm.. say around a 10dB antenna at Least.. maybe 600km spacecraft altitude... then you have your 30dB antenna, 30dB gain amp..
Basically your -60dB front end filter covering s-band aint gunna do the trick methinks.. I've just spent several weeks specifying and designing a massive front end filter then saw this.. screw it, im goin to the bar.
Probably won't work. It would only work for ferrous metal junk. Because iron and steel are quite heavy, and spacecraft designers trim weight as much as possible since it requires fuel, most space equipment is probably made of aluminum and titanium instead, and those are non-magnetic.
Even money bet that Northrup Grumman (Score:4, Insightful)
has created a sizeable percentage of the space-junk it's now offering to track.
Nifty business model, that.
Space junk (Score:1, Informative)
Probably nothing compared to the tests the russans [wikipedia.org] or chinese [wikipedia.org] did.
Here in the UK... (Score:4, Informative)
We have a system called NaviSys IV. The project has been going on since the '70s and originally involved large UHF and SHF antennas on balloons/blimps. That idea did not work out well as constant monitoring eventually was needed for tracking spy satellites and movements (e.g. attitude correction), and we went with a ground-based operation either running at L or S-band, but I can't remember which.
I used to be a technician for the tracking consoles back in the '80s before everything became fully automated. Everything then was mundane as it is now, and the old technology worked very well. Supposedly objects about a half metre were tracked, but that was "classified" information at the time.
It would appear to me that an American corporation is just trying to get yet another contract to do the same thing that they have been doing for years. VHF/UHF has some disadvantages, but the system in place is (or at least was) similar to the UK's. It looks like yet another money grab by the contractors to replace something that is fully functional and could operate for a generation or two at a nominal cost. What, after all, is a mere $30 million USD, though?
I sigh when I read these articles.
Parent
Bring forth Mega Maid! (Score:1)
And make her go from 'blow' to 'suck'.
Re: (Score:3, Interesting)
Everything then was mundane as it is now, and the old technology worked very well. Supposedly objects about a half metre were tracked, but that was "classified" information at the time.
Did you actually read the article? The current system tracks objects 4 inches and larger in diameter. The new system will track objects as small as 1/2 inch in diameter.
FTA:
"the United States Space Surveillance Network, managed by U.S. Strategic Command, is tracking more than 19,000 objects in orbit about the Earth, of which approximately 95 percent represent some form of debris. However, these are only the larger pieces of space debris, typically four inches or more in diameter. The number of debris as
Bakkster hit it, but a few other points (Score:2)
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They may have made it but it was your benevolent government that caused it.
I figured DHS was involved in the space fence... (Score:5, Funny)
To keep out the illegal aliens!
*insert rimshot here*
Re: (Score:1)
Or, to keep them in. Perhaps we're some sort of intergalactic Guantanamo for them.
Deorbit (Score:3, Interesting)
Re:Deorbit (Score:5, Interesting)
Launch water. You don't need to put the water into orbit, just release it in the path of whatever debris you want to deorbit and let your launcher fall back to earth. The debris loses velocity as it passes through a cloud of H2O molecules and slows down enough to re-enter the atmosphere. Sine you don't need the delta-v, the launches are fairly cheap, at least as long as we're at low altitudes.
Parent
Re: (Score:2, Insightful)
Me, I think a giant space vacuum cleaner would do the job.. we just need to borrow one from the folk at Space Balls.
Now *that's* thinkin with yer dipstick!
Re:Deorbit (Score:5, Informative)
But liquid water released into a vacuum will partly sublimate and partly freeze. Then the frozen water will slowly sublimate as photons from the sun hit it. If you can disperse the water fast enough in vacuum it should sublimate fast because of the huge surface area.
A different liquid (like Nitrogen) may do a better job.
Parent
Re: (Score:2)
Vacuums are not absolute things though. Even deep space is not a perfect vacuum, and I'd imagine high orbit's quality of vacuum is far from perfect.
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But I think these tiny molecules would quickly be pushed away by radiation pressure and maybe by whatever other part of the solar wind that makes it through earths magnetic field. UV radiation also ionizes, then you have charged molecules/atoms which allows one more force to interact with them.
Oh, and the boiling process would of course accelerate the particles in the first place, so a triple no-go!
Re: (Score:3, Interesting)
So maybe we need a mixture of CO2 and H2O at moderate pressure to get
Re: (Score:2)
IT's kind of expensive to get water into space. If you think about it, the space shuttle can hold a payload of about 50k lbs. That would be roughly 5,995 gallons of water without any containment structure. Now the containers would probably have to consume 1/3 or more of that capacity because not only do you need to contain it, you need to make sure the containers will withstand the G-forces necessary for launch into orbit and because of that much water.
To give you an idea of how much water 5,995 gallons is,
Re:Deorbit (Score:5, Interesting)
Parent
Re: (Score:2)
But something has to hit orbit in order to get it there doesn't it?
Never mind, I just remembered how short range ICBMs work.
Re: (Score:2)
IT's kind of expensive to get water into space. [...] Another problem with water floating in space, how would we keep it selective in only de-orbiting what is junk and not what is in use?
MichaelSmith [slashdot.org] has already provided a general answer, but here's some numbers to go with it.
"Look," Musk says, scribbling equations on a notepad, "the energy increases with the square of the velocity. To go 60 miles into suborbital space, like Rutan and the X-Prize, you need to travel at Mach 3. The square of that is 9. But to get to orbit, you need to go Mach 25, and the square of that is 625. So you're looking at something that takes 60 to 70 times more energy. And then, to come back, you need to unwind that energy in a meteoric fireball, and if there's one violation of integrity, you're toast."
Elon Musk Is Betting His Fortune on a Mission Beyond Earth's Orbit [wired.com]
Of course, we don't care as much about the return trip. We don't care at all about the water, and if we want to reuse the carrier, it's falling like SpaceShip One, not a space shuttle.
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Talk talk talk. Someone launch some damn water already so we can actually see what happens. Geez, do I have to think of everything?
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Current railguns can't d
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HTH
Re: (Score:1, Funny)
Bruce, could those be frickin' infared lasers?
I like where you're going with this.
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Not light pressure. Ablation.
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-Oz
Current Fact Sheet (Score:4, Informative)
The fact sheet [secureworl...dation.org] [PDF Warning] on the current VHF system in use.
public info (Score:1)
Planetes? (Score:4, Informative)
The Real Reason for the Space Fence... (Score:1)
The real reason for this space fense is to keep the illegal aliens out.
It's just not politically correct to discriminate against the Earth-challenged, so they have to come up with some other justification.
Trapped on earth (Score:4, Interesting)
Re: (Score:3, Funny)
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hiding places (Score:1)
Since we are talking about fabulously insane ideas (Score:1)
Re:Since we are talking about fabulously insane id (Score:2)
Giant magnets are hard to come by these days. It used to be, the earth naturally contained many thousands of millions of tons of giant magnets. Even amateurs long ago could dig them up and get themselves into all sorts of unexpected trouble. Now, things are different. We've devastated our natural resources, and man-made electromagnets just don't work the same way. In fact, that's the primary reason you don't see many giants loping around the hills wavi
Clean up space (Score:1)
Planetes (Score:4, Interesting)
Wasn't this covered in the TV show Quark? (Score:3, Funny)
I'm pretty sure that Quark covered the "Space Garbage Collection" technology... Why haven't we implemented this?
There's really no need... (Score:3, Funny)
And soon after it's installed... (Score:1)
Are any other satellite nerds worried about this?? (Score:2)
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Didn't you see Superman 2? A nuclear explosion in space could send super villains to enslave us all!
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Probably won't work. It would only work for ferrous metal junk. Because iron and steel are quite heavy, and spacecraft designers trim weight as much as possible since it requires fuel, most space equipment is probably made of aluminum and titanium instead, and those are non-magnetic.
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FFS!!! Don't go telling them that the solar system can launch a devisatating attack in just 30-45 seconds, what do you want, a war on space?!!