US Claims Satellite Shoot-Down Success 616
Readers of Slashdot last valentines day will remember discussing US Plans to Shoot down a damaged spy satellite. An anonymous reader noted that the US is
reporting success last night, thus saving us from hydrazine exposure. Of course this makes me wonder- if it's this easy, wouldn't an international super power war pretty much immediately mean the downing of every satellite in orbit?
in other news (Score:5, Interesting)
Re:in other news (Score:5, Insightful)
Re:in other news (Score:5, Funny)
I'm waiting for the anti-(anti-missile missile) missile
Re:in other news (Score:5, Funny)
The US Navy announced that due to bad weather, it will postpone the attempt to shoot down the impaired satellite until tomorrow at the earliest. Our zillion dollar "star wars" technology is clearly capable of stopping incoming missiles so long as: they come one at a time, are the size of a school bus, travel in orbits that have been calculated for months, don't deploy any decoys, and the weather is clear.
Re:in other news (Score:5, Informative)
Russia goes on about us using it as a cover for anti-satellite testing. As sh00z [slashdot.org] mentioned, it's an anti-missile missile. Then they ramble about how toxic fuel has crashed to Earth before and how they think it isn't a big deal. But since we didn't know where it would exactly land and don't have the luxury or using Siberia or Kazakhstan as a crash site, there could be enough risk of exposure to civilians as it was projected to hit North America. Besides, I'd like to hope we shoot for a higher safety standard than Russia. They do a lot of really cool things for really cheap
I found China's response is both hilarious and hypocritical. Their concern about security in space is a joke given that they hit a real satellite just last year. At 800 km against our 200 km! I think their test says more than ours in the international dick waving sense - plus a majority of their debris won't burn up within a week. I don't really see the two launches as apples to apples; more like China totaling a working 1993 Honda and the US totaling a 2007 BMW with a cracked engine block.
Odds are quite good that it was really just to destroy the top secret components on the satellite. Fair enough since it's our tech and we don't like giving it away. The environmental concern with the hydrazine happens to be convenient whether as a cover or for real legitimate concern - hydrazine is nasty stuff regardless. As for a weapons test, the missile couldn't hit a satellite in use. It really could only be useful as both a cruise phase interceptor test and a cold tracking (no infrared) sensor test. Besides, it's been known for years that the US can hit working satellites - no need to flip out over hitting a lame bird.
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that US stands by its decision to continue the development and deployment of weapons in space.
It might be useful to learn something about military technology before you make such pronouncements. The weapons system that was used was the RIM-161 SM-3 [designation-systems.net] ABM [wikipedia.org]. It was designed to engage and destroy tactical ballistic missiles. It doesn't even have the capability to reach most satellites -- this one was within range because it's orbit was decaying.
This weapons system has nothing to do with the "deployment of weapons in space", unless the USS Lake Erie [navy.mil] has some sort of secret warp drive that we don't k
They need to be more careful. (Score:5, Funny)
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"C... H... A??"
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priorities? (Score:5, Informative)
Re:priorities? (Score:5, Funny)
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Video (Score:5, Informative)
we know that they know that we know that ... (Score:4, Funny)
the BBC talking heads (on the BBS world news this morning) were being generous when they said that there is "some discussion" about the United States' motives for the missile strike
three possibilities were given:
I'm going to choose all of the above! U.S.A.! U.S.A.! U.S.A.!
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Some general woke up a couple of weeks ago and thought 'you know, we haven't shot at anything really fun for ages. I wonder if there are any satellites we could use for target practice.'
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three possibilities were given:
1. the US was showing that we have the ability to shoot down satellites (they described it as "shooting through the eye of a needle to hit the eye of a needle"),
2. we wanted to keep sensitive information out of the hands of our "opponents" (James Bond plot alert!), or
3. there might have actually been a health risk to letting the satellite reenter orbit (it should burn up now)
I'm going to choose all of the above! U.S.A.! U.S.A.! U.S.A.!
I believe #2 is the main reason, with #3 being a possible 'think of the children' reason. If by chance, the fuel from the satellite would have killed everyone within close proximity to it, then that would have been bad PR indeed.
I think the US would have loved to have taken this satellite out WITHOUT shooting it down. We had nothing to prove. This just makes it ever more difficult for us to come down harder on the next guy that says he wants to shoot down a "failing" satellite. China could easily caus
Yes they expect them to fall out of the sky... (Score:5, Informative)
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It's funny to think that it's basically the same technology, although the wiimote uses MEMS [wikipedia.org] accelerometers instead of high-precision gyroscopes (hence the error is way larger)
What's the big deal? (Score:4, Insightful)
Ob: Marvin (Score:4, Funny)
It's not about hydrazine- and it's not new. (Score:5, Informative)
2. The likelihood of the propellant tank making it to Earth in a populated area while still sufficiently intact to release hydrazine on impact is infinitesimal. The satellite was launched in 12/06, and represents the pinnacle (well, a year ago) of US spy satellite technology. There's plenty of good coverage in The Washington Post that supports both of these points.
Make no mistake about it, this is all about preventing the tech from falling into the wrong hands.
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Using the sat to test the SM-3 anti-missile saves millions as the sat is useless & an target platform will not need to be expended.
Video of the intercept (Score:5, Informative)
http://www.liveleak.com/view?i=71c_1203596547 [liveleak.com]
Like hitting a bullet with a bullet. Neat engineering feat.
Re:Video of the intercept (Score:5, Informative)
Cold War News (IE, Old Hat) (Score:5, Informative)
USN's Standard SM-3 missiles are their new Black and Decker tools of fleet defense. They pulled a preproduction bird off the table, loaded a ASAT seeker on it and sent it on it's way.
A little bit more on the new theater missile interceptor;
http://www.globalsecurity.org/space/systems/sm3.htm [globalsecurity.org]
So of course... (Score:5, Insightful)
Summary Info (Score:5, Informative)
USS Lake Erie [wikipedia.org]
Missle Used:
SM-3 [wikipedia.org] with kinetic interceptor [wikimedia.org]
Tracking was probably provided by the SBX [wikipedia.org] amongst other sensors.
Previous intercept videos of importance:
Japan Defence SM-3 test [dailymotion.com]
Prior shot from USS Lake Erie [youtube.com]
The propaganda that I find really funny is the DoD stating that it "nailed" [cnn.com] the fuel tank. C'mon, the impact probably released over 100 megajoules of energy. Were they really aiming for the "fuel tank" or just trying to hit the damn thing? With that much energy, who cares?
Big Dick waiving, yes. Technical success, yes. Political success, TBD.
On a side note, I was reading a story [bwcinet.com] written by a guy who was stationed at Thule AFB in Greenland where one of the first BMEWS (Ballistic Missle Early Warning System) Radars was deployed back in the late 50's early 60's. From a tech standpoint, it is quite fascinating what we could do back then with such limited technology and how it was accomplished. Read the intro through the epilog, I enjoyed it, so I'm passing it along...
Not every one, (Score:4, Informative)
It could be worse! (Score:3, Interesting)
It could be worse:
Pinata (Score:5, Funny)
OK, people... (Score:4, Funny)
Leave it to the Protocols of the Elders of Slashdot to put a negative spin on even this story.
OK, you want conspiracy?
Well, what *I* heard from my brother in law who knows a guy who reads the web site called thegovernmentislyingtoyou.org is that they are shooting down the spy satellite as a warning to the Space Station. It's basically NASA saying "We brought you into this world, and we can take you out of it."
The astronauts will be taken from the Atlantis and flown directly to the Vatican (the *real* Vatican hidden under the Antarctic ice pack) where they must restate their loyalty oaths to the New World Order, or face prolonged sentences in pain amplification devices at Gitmo. Those patches on the spacesuits are actually agonizers.
Seems those guys up there, especially when there's Russians on board, have been having whispered conversations (picked up by secret microphones placed on the ISS by the NSA, the DEA, the NRO, the Department of the Interior and the National Endowment for the Arts) involving phrases like "independent colony" and "breakaway republic in orbit" and similar subversive things.
Oh, and according to enterprisemission.com, smokingscalarweapon.com and the Facebook page of a former alien abductee, the window for shooting down USA 193 is defined by the eclipsed moon passing through the seventh house of Jupiter, and the alignment of Mars with a portion of the sky identified in ancient Vedic texts describing a nuclear war in India in 14,000 B.C.
This wasn't a sat-kill test (Score:5, Interesting)
The Chinese took out one of their telecomm birds last year. It was 500 miles up and in steady orbit. That was a sat-kill test.
The US spy satellite was a) 150 miles up, b) in unstable orbit and c) a spy sat.
Destroying the super-secret spy technology on the satellite was a bonus.
The shoot down was a test of whether US anti-ICBM systems worked as intended. THIS was the whole point. We've done contrived tests of the missile defense technology before, but here was an opportunity to shoot down a real, faster moving, unpredictably moving target.
Shooting down satellites in stable orbit isn't hard. The challenge is getting a missile up there, and the US has this technology locked. Shooting down a very fast moving object that is coming at you in a more or less unpredictable way is tough. The success of this test makes China and Russia nervous not about their satellites but about their ability to lob missiles.
As for all-our space-war, the challenge would be to be selective. The EMP from a small number of well placed nukes would fry the electronics of nearly every communication and weather satellite in space, not to mention taking the GPS system out of commission. Only a low-tech rogue nation with nuclear weapons, like N. Korea or Iran would in any way benefit from such tactics.
Re:Wasn't that the whole point (Score:4, Interesting)
Re:Wasn't that the whole point (Score:4, Insightful)
They needed to remind ME of that (Score:5, Funny)
As a matter of fact, I expect to see some damned fine shooting stars in the next few days, or I'll be asking for my money back.
Re:Wasn't that the whole point (Score:5, Insightful)
Re:Wasn't that the whole point (Score:4, Informative)
Gravity. It's closer to earth than the Chinese satellite was, so the effects of gravity are greater. Also the effects of the extremely thin atmosphere also slow it down and allow gravity to affect it.
Re:Wasn't that the whole point (Score:5, Informative)
The satellite that was shot down yesterday was very, very close to the Earth's atmosphere. It was only one rotation, maybe less, away from starting to graze it (which means that it would slow down and begin to reenter and burn up). If we assume that when it was destroyed, pieces flew in all directions, some of them would have ended up with a greater net orbital velocity at the end. These pieces aren't the ones that exploded *up* (normal to the surface of the Earth), though, they're the ones that exploded *forward* (in the direction of the satellite's motion). They picked up some velocity and would end up in a slightly higher orbit as a result. I suspect it's not much of a higher orbit, though -- if anything, it probably just means they'll take a little longer to hit the atmosphere than other parts. It's tough to say without doing any calculations, but I doubt you have enough Delta-V to push the pieces into a long-term stable orbit. (Unless maybe the rocket fuel detonated.) The difference in velocities between high, long-term stable orbits and low atmosphere-grazing orbits is pretty substantial.
The pieces that flew off in other directions aren't really a huge concern, because they all end up in the same or lower orbits. Plus because you've blasted the satellite into little pieces and thus increased its surface area tremendously, it'll start slowing down on hitting the atmosphere much more quickly, and the pieces will burn up more completely on their way down.
My understanding is that what the Chinese did was quite different. The satellite they shot at was way out in a stable orbit, and thus the pieces it was reduced to stayed there as well. So now instead of a dead satellite floating around in orbit that's relatively easy to track and avoid, you have a vast cloud of small debris. Not an improvement at all.
Followup and oblig. car analogy (Score:5, Informative)
The way most anti-satellite and anti-ballistic-missile weapons work isn't by blowing up the target, it's basically by just positioning itself in front of the target, and letting physics do the rest. The satellite has a huge velocity in one direction, the missile a huge velocity in the other, they slam into each other -- wham -- target destroyed.
Imagining the satellite just blowing up, with pieces flying everywhere, isn't a good model for the interaction. Although it's not impossible for some pieces to end up with a greater forward velocity than the satellite originally had, conservation of momentum tells us that most of the combined mass is going to end up with a velocity substantially less than what the satellite had to begin with.
(Car analogy: A racecar is going around a track at some incredible speed, say 200MPH. You decide to kill it by taking another car, and driving it in the opposite direction, intercepting the racecar head-on. Without getting too deeply into the mechanics of the collision, the result when the two cars smash into each other is that most of the pieces are probably going to be going less than 200 MPH in the racecar's original direction. Assuming the car's fuel tank doesn't detonate and add a lot of energy to the system.)
So overall, I don't think there's much of a risk with a kinetic ASW that you're going to blast pieces into a substantially higher orbit than where the satellite was originally. If the satellite is already in a high stable orbit, you may have a big cloud of junk in space for a long time though.
HD Modeling of the Chinese ASAT test ... (Score:5, Informative)
Good model of the debris field caused by the China ASAT test. As you mention, "stuff" doesn't just fly everywhere.
Re: Wasn't that the whole point (Score:5, Informative)
Orbits have a point of closest approach, which for the Earth is called perigee, and a point of farthest approach which as called apogee. Whenever an approximately circular orbit has a new velocity imparted, the orbit will become an ellipse. The counterintuitive thing about orbital mechanics is that the point where the velocity change occurred (in this case, where the missile hit) will not change on subsequent orbits.
Now assume a particle had an increased velocity because of the missile hit. It now has a "higher" orbit in that the point opposite the missile hit will be farther from the earth. However, its perigee is still the point where the missile hit. Atmospheric drag is significant at the satellite's current altitude, and thus it's velocity at that point will be reduced on every orbit, which will cause apogee to get lower and lower until the orbit is circular and it returns to the entire orbit decaying due to drag. This circularization time is small. Therefore, there is no concern about new orbital debris due to this satellite.
Anything that now has a reduced orbital velocity will only decay sooner, as its apogee is where the missile hit, and the perigee will be deeper in the atmosphere.
Re:Wasn't that the whole point (Score:5, Informative)
The satellite that was shot down yesterday was very, very close to the Earth's atmosphere. It was only one rotation, maybe less, away from starting to graze it
The satellite was never really out of the atmosphere, because as you go up in altitude, the atmosphere never really stops. The number of molecules per unit volume just gets smaller and smaller.
Every time a satellite hits a molecule, it loses a tiny amount of energy, and that lowers its orbit by a tiny amount. The lower the orbit gets, the more molecules get in the way, so the process gradually accelerates until the satellite "burns in".
At the high altitudes used by communications birds, the concentration of molecules is barely above that of deep space, which I believe is on the order of one per cubic meter, and it can take centuries for the decay process to get on a roll. At the other end of the scale, there is a tipping point around 150 miles up, where the satellite will be losing measurable altitude from one rev to the next, and reentry is imminent; that's where this satellite was yesterday.
In other words, the satellite was on the way down because it was getting lower in the atmosphere, not "close to it".
rj
Re:Wasn't that the whole point (Score:4, Informative)
Net velocity for the two masses (satellite and the missile) probability somewhere around 1 kilometer per second, assuming the missile had a mass that was about half the satellites upon impact and they where traveling at roughly the same velocity, only in opposite vectors. 1kps is really slow for orbital velocities. For example the space shuttle has an orbital velocity around 7kps to obtain a stable low earth orbit. Not quite the
oh, I personally agree that the primary reason for the shoot was saber rattling. But the "stated" reason, hydrazine exposure, has merit, IMHO.
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This was a known, failed satellite that was coming down in an unknown, possibly populated area. It still had a full load of hydrazine, which is poisonous. The satellite was already in a low orbit, and any debris from the missile impact would deorbit in a short period of time.
The Chinese shot a shut-down satellite that was in a stable orbit approx 528 miles up. They created over 4000 pieces of debris in the same orbit, half of them over 4 inches in size.
The only dick tha
Re:Wasn't that the whole point (Score:4, Informative)
This is a cover story and nothing more. The hydrazine has a low boiling point (114C). The high temperatures from the satellite rentry would have boiled the hydrazine and caused fuel tank rupture LONG before the satellite hit the ground.
The reasons the military shot this down are simple:
#1: To remind China we can do it, and we're so sure we can do it we have no problems being put on the spot about doing it.
#2: This was a spy satellite, as such it has a lot of very secret very advanced tech, which since it *IS* a spy satellite often flies over land we don't control. The military did not want anything to be recovered by another country. The US has recovered satellites from the former Soviet Union, so we know how much can survive.
Re:Wasn't that the whole point (Score:5, Interesting)
I contend that this was a 3-for: the US got to test it's anti-ballistic missile system, got to protect its secrets, AND got to reduce the risk to people. And for what? No risk whatsoever. If it missed - no change in situation. It hit, though, and so now everything will just burn up.
Re:Wasn't that the whole point (Score:4, Insightful)
Insulated != Protected against re-entry. It was protected against the cold of space, not the heat of re-entry. I wear a raincoat to protect against getting wet in the rain, that doesn't mean I won't get wet if I jump in the ocean. Even if the tank were covered by the tiles that protect the space shuttle (which BTW is one of the reasons the Shuttle Hydrazine tank survived reentry, other reasons are it was on a stable deorbit, was protected by the shuttle itself, and the shuttle didn't break up until much later in reentry than this satellite would have.) then the hoses and the piping to the other parts of the satellite would have burned away, and opened up the tank for hydrazine to "leak" out.
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Re:Wasn't that the whole point (Score:5, Funny)
Re:Wasn't that the whole point (Score:5, Informative)
Not necessarily. If the hydrazine tank is parked in the center of the vehicle it's very probable that it could remain cold enough. You completely negate radiation and most likely convection depending on design, so you rely solely on conduction for heating. If you have a big, massive satellite that is densely packed it is conceivable that the center could remain cold, just like the Apollo modules kept three people comfortable for reentry. Also a big dense object like a satellite is likely to stay intact through re-entry with very little breakup.
Although I agree there is much more at stake than just hydrazine, and I think spy secrets alone would have been justification, there's no saying the hydrazine would be completely gone. There's multiple justifications for this shot, they just picked one to tell people.
Re:Wasn't that the whole point (Score:4, Informative)
Except a similar hydrazine tank on the Columbia did survive and the fuel was still liquid inside. Which is why it was believed by NASA this one would survive as well.
Personally, I think the risk was overblown (the chances of it affecting a populated area are slim, but better safe than sorry, I guess), but to say everything bad would have burned up on re-entry is unsubstantiated and probably wrong.
Re:Wasn't that the whole point (Score:5, Insightful)
1) Because the risk to human life was non-zero
2) To prevent sensitive technology from going into the wrong hands. (You can bet that there would have been a mad dash to salvage at ground zero by just about everybody once it went down)
3) To further test our ABM technology.
4) To show everybody once again that we kick ass.
5) And most importantly: Because there were no downside to doing it. This wasn't a dangerous mission that put soldiers or civilian lives at risk. We launched a missile, and if it missed, no big deal, no harm done. But if it was a success, we can celebrate because of reasons #1-#4.
There really isn't any valid argument for not trying this operation.
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Re:Wasn't that the whole point (Score:4, Insightful)
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Still wanna try to claim that tank would survive reentry?
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Re:Wasn't that the whole point (Score:4, Insightful)
Re:Wasn't that the whole point (Score:5, Informative)
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Re:Wasn't that the whole point (Score:5, Informative)
It's not as bad as they make it out to be. Ocean water is corrosive; alcohol is toxic; many solvents are mutagenic; lighter fluid is flammable. All of those things are stored in tanks.
Hydrazine is corrosive, but so are most things that are stored in stainless steel containers (although chlorides are typically not stored in stainless steel, it causes cracks). The hydrazine tank on the F-16 is stainless through and through, as are the tubes and hoses that it would utilize if the epu is fired. Here's a picture of the F-16 epu tank:
http://www.advpack.com/custom_shipping_cases/custom_cases.html [advpack.com]
It's the cylinder in the second case down. For reference, the tank is about 3.5-4 feet long. I'd say it holds about 15 gallons or so. That tank IS pretty heavy-duty, as you mentioned; it typically survives a crash. However, the tank and associate hardware, when filled, weigh upwards of 150 pounds, which would be unacceptable for a satellite that did not have to endure frequent landings or a crash. It is very likely that the hydrazine tank on the spy sat is nearly identical to this one...
http://www.psi-pci.com/images/80200.jpg [psi-pci.com]
I doubt that it would have made it to the surface. Even if it did hit a house, it would probably only do as much damage as an equally-sized and massed device would. Ke=1/2mv^2 and all that.
I personally know of at least one person here on base who's been exposed to hydrazine, and he's fine.
-b
Re:Wasn't that the whole point (Score:5, Interesting)
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Second, even if the tank didn't melt, it would still undergo structural failure at some point due to the terrific pressure hydrazine would generate at those temperatures. And as soon as the containment failed, the hydrazine would begin to decompose. Since it is a monopropellant, it wouldn't need the presence of another gas for this react
Re:Wasn't that the whole point (Score:5, Informative)
Absolutely I would claim that.
Hydrazine is a solid below about 1 deg C. This was a dead satellite. No heat, no power supplies. In other words, you have an insulated pressure vessel (fairly well-built) containing 1,000 lb of hydrazine ice at roughly -273 deg C. That's a LOT of thermal mass; the ice inside the tank would absorb a lot of the reentry heat, preventing the metal from melting for quite some time. Did you ever do that science experiment where you try to burn a paper cup containing water? Doesn't work until you boil off all the water. Same thing here, but we're talking about metal which is even more thermally conductive than paper.
Furthermore, a lot of the surrounding structure must ablate or melt away before the tank can be directly affected by the reentry.
Also, in case you want to compare a thousand-pound meteorite to this satellite: a satellite does not orbit as fast as your typical meteor reentry speed, so you cannot compare the reentry energy to a typical meteorite ablation rate.
If you need proof, consider that hydrazine tanks from the Space Shuttle Columbia accident DID impact in some Florida woods. They were NOT cold-soaked at absolute zero for two years - they were prepped for flight, heated, etc., and wrapped in far more spacecraft structure than this satellite. And they were not full, like these tanks were. That should demonstrate the reality of this risk.
Want to see a photo of a far smaller hydrazine tank, and some other unidentified tanks, AFTER they landed in Florida? http://www.io.com/~o_m/clfaq/s3.htm [io.com]
http://www.io.com/~o_m/clfaq/images/debris_shots/tank1.jpg [io.com]
http://www.io.com/~o_m/clfaq/images/debris_shots/tank2.jpg [io.com]
http://www.io.com/~o_m/clfaq/images/debris_shots/tank3.jpg [io.com]
Most interestingly, these bits of spacecraft look completely uncharred, unmelted, almost new except for a lack of paint.
Re:Wasn't that the whole point (Score:5, Informative)
First, the Columbia hydrazine tank was part of the Columbia...a shuttle. The satellite tank was part of an object that was never designed to survive reentry.
Second, the hydrazine tank on the Columbia was shielded from the worst of the reentry temperatures. The Columbia didn't lose integrity and break up until well into the atmosphere.
Third, the tank was found ruptured.
There's nothing 'similar' about the two scenarios, and the Columbia tank ruptured anyway.
Re:Wasn't that the whole point (Score:5, Insightful)
Mostly likely they were just worried about sensitive technology that might survive reentry potentially falling into Chinese or other hands. While not a new sat, it wasn't really that old either. I'm guessing decent optics and other gear on there, including comm equipment. Why risk any chance of parts of that surviving and landing in even a damaged state someplace that a foreign power might be able to get a hold of it.
Of course this idea was never even remotely touched on, which I'm guessing is exactly what the military wanted. They are probably more than happy to be getting accused of testing a missile, it means people aren't talking about the thing that really concerned them.
Re:Wasn't that the whole point (Score:5, Funny)
Oh c'mon everyone...at the very worst, the hydrazine was just an excuse to do something very cool....shooting a missle to blow up a failing satellite. Cool stuff, and no one got hurt.
Re:Wasn't that the whole point (Score:4, Interesting)
You may be claiming that it's demonstrably false, but you haven't successfully demonstrated it. And unless you're a materials engineer with access to technical drawings of the satellite and a good simulation of its reentry profile, you're not going to.
You're clearly making huge hand-waving generalisations about something which you don't have the slightest clue about. As usual.
Re:Wasn't that the whole point (Score:5, Informative)
Re:Wasn't that the whole point (Score:5, Informative)
They can wave that dick all they want. (Score:3, Insightful)
At least the US didn't dump hundreds of objects into space because of some idiocy guided test as did China. Hell you could claim the threat is about nil
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Here's a material safety data sheet for hydrazine: http://www.sciencelab.com/xMSDS-Hydrazine-9924279 [sciencelab.com] (pdf). It is extremely nasty stuff. Note in particular the full-suit requirements, and the teensy-sized lethal exposure levels.
Hydrazine is one of those substances where if you can smell it, you're already dead.
So maybe this is just a little drama. Maybe there w
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No Hydrazine would make it to the surface of the earth in that form.
Re:Wasn't that the whole point (Score:4, Insightful)
Why would you simply assume this would happen? For all we know, the hydrazine could be insulated well enough that it would survive reentry only to break open on impact. Keep in mind that they need to design the tanks to be more than adequate enough to hold together during launch as well as any possibility of aborted launches- it's more than likely that said tank would stay together upon reentry, right? After all, if we can make containers that can keep worms alive [bbc.co.uk] during a shuttle breakup, what makes you think we can't make tanks storing a reactive chemical that would stay intact upon reentry?
Either you have classified info about the satellite, or you're simply talking out your ass. I'm willing to put money on the latter.
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And you know this how exactly ?
Re:Wasn't that the whole point (Score:5, Insightful)
Physics. The satellite wasn't designed for re-entry (In fact, it's very likely it was designed for breakup during reentry for various security issues) and as such wouldn't have the heat shielding required to protect those parts of the propulsion system from the heat of reentry.
Re:Wasn't that the whole point (Score:5, Informative)
Maybe you should look at some of the photos of the skylab debris before making your assumptions.
Re:Wasn't that the whole point (Score:5, Informative)
After all... (Score:3, Funny)
Re:Wasn't that the whole point (Score:5, Insightful)
What irked me the most was China's whiny statements about the test, which was extremely benign in every regard, while China themselves produced a huge band of debris in a very useful polar orbit for no legitimate reason whatsoever.
Re:Wasn't that the whole point (Score:4, Funny)
Re:Wasn't that the whole point (Score:5, Insightful)
Comment removed (Score:4, Interesting)
Re:Wasn't that the whole point (Score:5, Informative)
Re:Wasn't that the whole point (Score:5, Insightful)
"In theory, practice and theory are the same; in practice, they are not."
Anyone who has actually had to do installs knows that ABSOLUTELY NO AMOUNT OF LAB TESTING WILL PREPARE YOU COMPLETELY FOR THE REAL WORLD. See: Murphy's Law. See Also: Any angry IT guy: "Dammit, it's ALWAYS something!"
Re:Wasn't that the whole point (Score:5, Insightful)
Simulations are doomed to succeed.
Re:Wasn't that the whole point (Score:5, Interesting)
prior to this the maximum ceiling of the missile used was unknown.
We still don't, we're talking about shooting satellites so ceiling doesn't really apply. It is known that the velocity of the missile will taper off as it gains altitude due to gravity and because it's a kinetic kill vehicle that means it's effectiveness is a function of the closing velocity between the warhead and the target. Each potential target is going to present it's unique set of variables through a blend of engineered friability to break it up into small pieces on re-entry to protect the secrets onboard or the public on the ground and the hardening to make it less vulnerable to the space environment and attack; So each satellite shot is unique.
This bird they used, The RIM-161 Standard Missile 3 (SM-3) [wikipedia.org] seems from the description to be rather modular, I bet they can mix and match rocket motors in the various stages to get the parameters they want without to much difficulty. I'd be surprised if we couldn't reach-out and pick off a geo-sync satellite if we wanted to.
Something to keep in mind (Score:5, Informative)
It is known that the velocity of the missile will taper off as it gains altitude due to gravity and because it's a kinetic kill vehicle that means it's effectiveness is a function of the closing velocity between the warhead and the target.
Remember - orbital speeds are fantastic. [wikipedia.org] If we could simply lob a brick in front of the orbital path a satellite - the closing velocity would still be massive.
Most of the kinetic heave-ho that will kill the satellite is probably coming from the satellite itself.
Re:Wasn't that the whole point (Score:4, Informative)
Of course we are talking about budgets and politics and there will be spin. Anyone who actually knows in high detail what has happened, is happening and what current capabilities exist, wont be posting here. I feel comfortable saying that the US military has successfully demonstrated that it has the capability to take down satellites in the past. I also feel comfortable with the idea that modifying an sm3 to do the same and then testing such is not a huge mistake because it gives away too much to the Chinese. But everyone is entitled to their opinion - I'm just sharing mine.
Re:Wasn't that the whole point (Score:4, Informative)
Re:Wasn't that the whole point (Score:5, Insightful)
http://en.wikipedia.org/wiki/SM-3 [wikipedia.org]
The problem with hitting a satellite is velocity. Specifically closing velocity. With the kinetic warhead traveling at the speeds that it is capable of and the satellite orbiting around 17,000 mph, closing velocity was up around 22,000 mph. Altitude can always be achieved just by changing the booster series and fuels. Having a guided warhead being able to adapt to and intercept a target moving that fast is the real problem.
I think the capability was soundly demonstrated and while some may think it was a mistake, the BMD system has roots in a previous system that dates back to 1995-96. This capability has been in the hands of the Navy for a while now just no reason to use it or give away what cards were being held in our hand. It was also being developed at that time when we signed the Anti-Ballistic Missile Treaty which not only said we wouldn't develop any new ballistic missiles but we also wouldn't develop a defensive system against ballistic missiles. As far as I know, that treaty is still in place and this is a direct violation of that treaty. Just goes to show how much the Navy cares about foreign policy. Especially since it can park "90,000 tons of diplomacy" off of any shore and have it accompanied by a battle group with enough firepower to put any country that opposes the U.S. back into the stone age.
Re:Wasn't that the whole point (Score:5, Interesting)
Now I personally did not know that we had a ship based missile capable of knocking down satellites but apparently we do. However, that is likely not an epiphany for any other country that is capable of fielding an ASAT weapon system. It's highly likely that several other countries were even informed of the planned launch to forestall any tensions that it might have created.
If we did give away any important information as a result of this launch, it's that our president is capable of making rationale decisions every once in a while. It's entirely possible that countries such as China and India were not aware of that.
Re:"all guns blazing"? What??? (Score:4, Insightful)
Re:"Pull!" [ratchet] [BANG] [ping!]... "Pull!" ... (Score:4, Insightful)
When everyone can destroy satellites, why should the US allied sats survive ?
Re:"Pull!" [ratchet] [BANG] [ping!]... "Pull!" ... (Score:5, Informative)
If you start blowing up sattelites in stable orbits, you are playing a kind of russian roulette that could start a chain reaction, destroying all satellites in a given orbit zone. The fragments of broken sattelites don't slow down, like on earth, nor is the chance that they come down to earth and burn up in the atmosphere particularly high (especially with high-altitude orbits). They will mostly start zinging around the earth in various orbits until they make contact with another satellite, causing more debris. Here, I use the word satellite in it's loosest sense: meaning a conventional communications satellite, or a space shuttle, or a space station, an astronaut on a spacewalk or even the moon itself.
This kind of event would make the orbits unusable for the foreseeable future - it is a real risk even without people blowing things up - and we don't yet have a good solution. Research is focussing on using things like aerogel to trap this kind of debris and bring it out of orbit. As long as you can take more debris out of orbit than is being created, you should be able to prevent a chain reaction. But for the moment there is no solution.
Re: (Score:3, Informative)
GPS sats are 12600 km up, that's not exactly "low orbit".
Re: (Score:3, Informative)
Re:In other conspiracy-related news... (Score:4, Insightful)
Re: (Score:3, Interesting)
Re:In other conspiracy-related news... (Score:5, Insightful)
I would envision the threat scenario of the Chinese threatening the US in any significant financial way would go like so
1. China: We are cancelling all our loans and investments and want our money back now.
2. US: No.
3. China: Ummm