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US Claims Satellite Shoot-Down Success
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?
The US government has now tested it's anti satellite missiles without looking like complete hypocrites for criticizing China for the exact same thing.
I took a look at the sky late last night, and it seems they took a chunk out of the Moon as well.
Slashdot Burying Stories About Slashdot Media Owned
A video ... A great success! Huzzah!
There was no need to show off, we had already shot down a satellite in 1985. The big difference here is that we did this one from the ground. Good job!
High orbit and low orbit are not even close to the same thing in regards to space junk causing trouble. China's mess will stay up there for decades or even centuries.
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.!
It ain't what they call you. It's what you answer to. http://mylyceum.us/
When everyone can destroy satellites, why should the US allied sats survive ?
EXACT same thing? I beg to differ.
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 that's waving around here is you.
I'm not crazy,I'm actively irresponsible.
I agree about the military posturing, but it's important to point out that China did not in fact do exactly the same thing -- the Chinese satellite was in a fairly stable polar orbit, so the debris cloud from that exercise will be an orbital hazard for hundreds of years. The American military at least had the decency to toast a decaying satellite, so the debris will re-enter sooner rather than later.
2*3*3*3*3*11*251
We've been able to shoot down satellites since the 80's. I'm not sure what we gave away here.
It's hard to believe that's how Micronians are made. Why don't we see it right now by having you both kiss one another?
Because frankly given a choice between China running over the world or the US I would much prefer the latter. The way the world bends over backward for China; forced abortions, daily Taiwan threat, incredible number of deaths in mines, world leader in executions; makes me wonder just what the hell is everyone so bent out of shape about the US doing this?
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 for any space object falling from the sky, the problem is that nil becomes a really big number when it lands in your backyard.
Go and keep waving that dick, it just lets the loonies of the world know that they really aren't in a position to ignore the US or Europe (because I count Europe in a lot of these things - don't for a momnet believe they didn't want it to work). Dick waving is a helluva lot better than throwing actual bombs with little Mr. Mushrooms around
* Winners compare their achievements to their goals, losers compare theirs to that of others.
All of our weapons, bombs in particular, are guided primarily by inertial guidance systems. They rely on GPS simply to increase accuracy, though the GPS updates take a significant amount of time relative to the distance the bomb has dropped. The weapon relies on the inertial guidance for most of it's trip, using the GPS to correct for errors that occure over time because of physical constraints inherent in the inertial guidance systems. With or without GPS they will still be deadly accurate.
I've read Slashdot for the last 5 years, and now I start posting... Go figure
I mean when looked at from a geeky stand point shooting down a high fast moving object from a ship based platform is rather cool.
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.
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.
Do you Gentoo!?
Where's the ka-boom? There was supposed to be an earth-shattering ka-boom!
Slightly disreputable, albeit gregarious
Here's a material safety data sheet for hydrazine: http://www.sciencelab.com/xMSDS-Hydrazine-9924279 (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 was a secret self-destruct device in the (totally secret) satellite, and they pushed the button just as the missile approached, thus guaranteeing a success.
But do NOT disrespect the hydrazine.
Never attribute to malice that which can be explained by mere idiocy.
Which was the whole point of this exercise. The US thought the tank would survive reentry and they fired the missile with the purpose of rupturing the hydrazine tank. People need to easy on the cool-aid conspiracies, the anti-missile missile they used isn't even capable of reaching high-orbit so this isn't a anti-satellite weapons test.
It's much worse than that....
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.
Really? Considering that the US shot down a satellite over two decades ago, from a missile fired from an F15 of all things, I don't think the USA had a whole lot to prove. In fact, I think the military people are smart enough to not give any inkling of just what they are capable of (like the amazing fact the F-117A stealth fighter was kept secret for so long, until its unveiling during Desert Storm).
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.
Better known as 318230.
1. The US has shot down satellites before- in the 1980s. We've had this technology for a long time and everyone knows it. While there may be an element of dick-waving in this action, any nation with a developed intelligence infrastructure (or not, as it was in the press) has known for a long time that the US is capable of this.
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.
Video of the intercept and relevant Pentagon briefing at:
http://www.liveleak.com/view?i=71c_1203596547
Like hitting a bullet with a bullet. Neat engineering feat.
Ander
@=
Back in the 70's and 80's both sides had ASAT weapons available, or were in testing. The Soviet Union had their orbital satellite killer. Fired atop a Proton booster, it would make orbit and line up with it's target, close and detonate it's warhead, turning it into swiss cheese. The USAF had a more flexible ASAT missile that looked alot like a supersized Phoenix air to air missile. It was tested on one target with a spectacular skin-skin kill as a result before the politicals kicked in and put a moratorium in place to keep the peace. One upshot of the ASAT weapon is that it could hit targets on a moment's notice. The USSR killsat you could dodge, as long as you had the fuel to do it. Neither of these could hit the geosynchronous birds, they were tailored to go after recon and commsat snoopers.
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
First rule of holes; When in one, stop digging.
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.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
... this is irrefutable proof that our missile defense system is totally awesome, flawless, and deserving of billions of dollars of tax investment, right?
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
I call bullshit. I have worked with hydrazine quite a lot for my Ph.D. and it is nowhere near what you scare us with. It is toxic, sure, just like most of organic chemistry, but in high concentrations and on prolonged exposure. FYI, LD of 500 ppm is equal to 0,5% concentration. It doesn't smell that bad, compared to other small-molecule nitrogen compounds. As many have mentioned, during reentry all the material would have completely vaporized and burned (i.e. oxidised) far above ground level. Talk about pretexts.
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.
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.
prior to this the maximum ceiling of the missile used was unknown. They now know it can leave the earths atmosphere. Even our own media was under the idea it would take up to 5 shots before a missile directly hit... we did it in 1.
"Slashdot, where telling the truth is overrated but lying is insightful."
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.
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 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.
Sigs are for losers
Ship that took the shot:
USS Lake Erie
Missle Used:
SM-3 with kinetic interceptor
Tracking was probably provided by the SBX amongst other sensors.
Previous intercept videos of importance:
Japan Defence SM-3 test
Prior shot from USS Lake Erie
The propaganda that I find really funny is the DoD stating that it "nailed" 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 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...
I am not a rocket scientist and neither are you, but I have been told by a satellite guy that the hydrazine has to last for the entire duration of the satellite's mission, and so the tank is extremely well insulated. It may survive re-entry with at least some content. If you want to dig up another satellite guy with a contrary opinion, go right ahead. It's a moot point, though, since neither of us is going to find a guy willing to talk about this particular classified satellite.
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.
Do you Gentoo!?
The maximum ceiling is still unknown. There's a very good chance that the people modifying and firing the missile weren't sure how many shots it would take, now they know too. There's no substitute for real experience, and I think what information was given up was a decent trade off for what was gained.
It's hard to believe that's how Micronians are made. Why don't we see it right now by having you both kiss one another?
I disagree. The reasons we shot it down were:
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.
Yep, but the military felt they needed to remind china of that.
And you know this how exactly ?
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.
Do you Gentoo!?
Except the Chinese shot down a satellite that was in orbit ~460 mi above the earth, the US satellite's orbit was ~130mi.
-- Cave quid dicis, quando, et cui
Please, when someone starts waving around their 8 inch hardon you don't counter by pulling out your 4 inch softie. If this was a dick waving contest we would have used a bigger dick.
Hydrazine is highly corrosive (in addition to being highly toxic, mutagenic, carcinogenic, and flammable. About the only thing it isn't is radioactive) and wouldn't be stored in steel tanks. Even tiny amounts of it are dangerous to humans. What's more, because it's so nasty it's likely stored in a rather sturdy container. Hydrazine containers were some of the larger chunks that survived the Columbia accident for example. Hydrazine is one of the big reasons NASA tells you never to handle any shuttle/satellite debris you might find.
I read the internet for the articles.
Some one correct me please.
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.
Do you Gentoo!?
Completely different scenario, chuckles.
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.
____
~ |rip/\/\aster /\/\onkey
Why would there be anything else? Satellites are designed to stay in space. Any re-entry shielding would be extra weight and hence extra cost for launching, for no intentional purpose.
I think you're maybe misunderstanding a little of how 'orbit' works. In order to go 'up' or 'down' in orbit, you really need to go faster or slower. That is to say, if you want to get into a higher orbit, you need to accelerate, and start moving faster around the Earth. You don't just push up perpendicular (normal) to the Earth's surface, that doesn't work. (Well, it will work temporarily, but it won't get you into a higher orbit. You'll just fall back down, because you're not escaping gravity. Remember, orbit is all about falling towards the Earth but moving fast enough to miss it, continuously.)
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.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
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.
Pirate Party UK
The tank was made of Titanium - melting point of 1700 degrees Celsius.
Weapon systems capable of shooting down a satellite is nothing new. The US and the USSR explored using nuclear tipped missles in the early 60's that could get close enough to a satellite to bring it down. Several countries experimented with high powered lasers as a method of disabling or destroying satellites. The Soviets experimented with so called "Killer Satellites" that would take out a target with the orbital equivalent of a giant shotgun. Since the mid to late 80's, the US Air Force has had an ASAT(Anti Satellite) missle called the ASM-135 that was fired from a F-16 at extreme altitude and would seek out and collide with its targets as opposed to exploding near them.
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.
I think the whole discussion of missile tech and the tank idea are both kinda of silly. I think the story was one that the military used to justify shooting a missile, but not to test the missile or any other tech.
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.
>Still wanna try to claim that tank would survive reentry?
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
http://www.io.com/~o_m/clfaq/images/debris_shots/tank1.jpg
http://www.io.com/~o_m/clfaq/images/debris_shots/tank2.jpg
http://www.io.com/~o_m/clfaq/images/debris_shots/tank3.jpg
Most interestingly, these bits of spacecraft look completely uncharred, unmelted, almost new except for a lack of paint.
--Brandon / Split Infinity Music
I'd also point out just as a followup to myself, that the assumption "when it was destroyed, pieces flew in all directions" is probably not a good one to make, either.
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.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
We have just witnessed the worlds most expensive pinata. With no candy. Next time they need to just pay a few bucks at the mercado, invite a few kids, and do it right.
The world is made by those who show up for the job.
Meteorites are still freezing cold in the center when they hit the earth, only the outside is heated.
Maybe you should look at some of the photos of the skylab debris before making your assumptions.
love is just extroverted narcissism
I've seen the term "dick waving" quite enough for one day.
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.
No, not exactly. Satellites have highly circular orbits - this keeps them at a maximum distance from the Earth at all points of the orbit, and hence keeps atmospheric drag to a mimimum.
To increase the altitude of a sattelite, you need to do two burns - the first burn accelerates the satellite in the direction of it's orbit. This produces an egg shaped orbit, known as a transfer orbit. The round end of the 'egg' is near the Earth, and the pointy end is the point the furthest from the Earth. When the satellite subsequently reaches the pointy end, a second burn is executed, that makes the orbit circular again. I don't remember exactly what the vector of this burn has to be (a tangent to the circular orbit of that altitude I think...), but anyway, the idea is that you use energy to raise the average altitude of the orbit up to the highest point of the transfer orbit. It normally takes several burns over several orbits to achieve a highly circular orbit.
Disclaimer: Take all of this with a grain of salt. I'm not involved with the space industry. It's just that I wrote a game a while back where you are in a space ship protecting the earth from a hoard of attacking satellites that were bombing the Earth. The game was like good ol' Asteroids, you spin left, right, shoot and accelerate. But the thing was, both the satellites and the space ship were in orbit around the Earth, and I modelled gravity. What I just explained above was the technique I used as the player to raise the altitude of my ship's orbit...
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.
Light travels faster than sound. This is why some people appear bright until you hear them speak.........
I would say your boss needs to understand the most basic maxim of IT:
"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!"
Just to adding to your excellent explanation of orbital mechanics, this shootdown effort will not significantly affect the time it takes for the the pieces to come out of the sky regardless of what new velocity they have been given.
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.
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) 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.
Apocalypse Cancelled, Sorry, No Ticket Refunds
Hydrazine is not explosive. It is very reactive, but not explosive. People watch to many movies.
.09kps for a space shuttle de-orbit velocity, but by no means a stable low earth orbit velocity. Shuttle information: http://spaceflight.nasa.gov/shuttle/reference/shutref/sts/requirements.html
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.
This document http://www.ucsusa.org/global_security/space_weapons/a-history-of-asat-programs.html has some good information, to my knowledge. It also reflects my understanding that programs like the almv program were stopped because of political considerations rather than technical problems. This article http://www.globalsecurity.org/space/systems/almv.htm seems to reflect the same.
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.
It's hard to believe that's how Micronians are made. Why don't we see it right now by having you both kiss one another?
Or maybe because the Chinese would stop their lending programs, stop the cash flow and take their assets back, completely tanking our governments military fund.
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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
The fact that the missile used shot down a satellite does not mean that the purpose here was to see if we could shoot down a satellite. Look here...
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.
-- What you do today will cost you a day of your life.
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
Screw China, I'm a US taxpayer and I need to be reminded that the insane amounts of money being spent away by the military are at least useful for SOMETHING.
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.
Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
Adding to your thought:
Simulations are doomed to succeed.
Distance isn't the problem. The SM-3 is a multi-stage missile and was already above it's published service ceiling for this test.
http://en.wikipedia.org/wiki/SM-3
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.
http://celestrak.com/events/Xichang-ASAT4.wmv
Good model of the debris field caused by the China ASAT test. As you mention, "stuff" doesn't just fly everywhere.
Probably ill informed, I don't watch the news very often. Say, did they ever find all of those WMDs I used to keep hearing about, (and which you seem to be offering as an excuse for the invasion)?
which is totally what she said
IWAHED (I work around hydrazine every day):
...Which is sturdy, but only meant to hold 485 PSIG. I'd say the wall thickness is probably between .060" to .080" to keep it light. I'm going to say that it might not be titanium, which is very sucseptible to hydrogen embrittlement.
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
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
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
No offense, but I've stopped responding to AC's.
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. 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.
Weaselmancer
rediculous.