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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.
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!
OK, the articles I've seen show some sort of rocket taking off. How about a picture of an explosion at the other end? Surely with such a highly publicized thing as this there were telescopes pointed in that direction, perhaps some photographic satellites as well?
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. The people of the US don't necessarily have to be in trouble, a lot of produce can still be obtained without the Chinese, so we won't go hungry and a lot of the Chinese industry can be replaced with eastern-european or local industry. Sure the prices would go up (although the prices and wages would stabilize to support a self-sustaining economy) and the standards of living would go down a bit but we can survive without the Chinese, the government as it is run today can not.
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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.
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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.
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Hydrazine has a boiling point of 113.5 degrees Celsius. Reentry temperatures typically reach 1400 degrees Celsius. Steel melts around 1370 degrees Celsius.
Still wanna try to claim that tank would survive reentry?
____
~ |rip/\/\aster /\/\onkey
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Sorry if this was already posted. Here is actual footage of the shoot down.
/Not a rick roll I swear.
http://www.youtube.com/watch?v=sfk2m60z9EI
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That's completely wrong. Sorry, I don't know another way to say it. Take a look at estimates on the acceleration we've seen in having to retire equipment and procure new equipment due to the conflict in Iraq. This has not been a full out war between two evenly matched opponents. The training tempo and op tempo are never the same. If we had gone toe to toe with the USSR it would have been over, I'd guess conservatively, in less than 6 months. We'd start running out of missiles and other ordnance. Air frames would be failing left and right. Engines going down, armor wrecked in ways that would not be reparable or would take an extremely long time to repair, etc. The only real question would be who would weaken first and then if they would go nuclear rather than lose.
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?
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.
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leaving their launch sites more vulnerable.
If it were done when 'tis done, then t'were well it were done quickly... MacBeth
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.
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The tank was made of Titanium - melting point of 1700 degrees Celsius.
When can I have that inertial guidance in my Wiimotes?
It's funny to think that it's basically the same technology, although the wiimote uses MEMS accelerometers instead of high-precision gyroscopes (hence the error is way larger)
Misleading titles? Inflammatory blurbs? Keep in mind that Slashdot is a tabloid.
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.
First, can you provide a link that states this conclusively? Hydrazine propellant tanks are also made of steel, coated with titanium or other metals to prevent corrosion.
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 reaction to commence, and the entire tankful would break down in short order.
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~ |rip/\/\aster /\/\onkey
It was a neat hack too as they had to modify the systems sensors to work on a 'cold' satellite, and they did it in a month.
love is just extroverted narcissism
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...
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.
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Actually, this was a pretty good reveal. My feeling is that you need to reveal a few cards now and then for optimal strategy. The US's rivals would get only limited information from a successful test. And now they have to factor ASAT into strategic space decisions. At the least, the know-nothings will have to be placated. This might take the form of greater numbers of satellites with improved manueverability at the cost of additional weight and capability. In other words, the Russians and Chinese need to spend more for their space assets in order to counter this threat even if the US never does much with it.
For the curious, hydrazine's nastiness also one of the reasons why they tell you not to mix household cleaners: http://www.bbc.co.uk/dna/h2g2/A795611
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H-70 is used in F-16 APUs to power the turbine that drives the emergency generator and hydraulic pump. Every year-ish or so an EPU would fire by accident, and sometimes a ground crewman gets sprayed by the exhaust (stupidly located ABOVE and to the rear of the safing pin).
Standard procedure is hose them off outdoors, then send them to hospital for checkup. I never met any troops who were sprayed and expressed any symptoms.
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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.
Well, cost is a valid argument.
Public sources put the cost of the shot at $40-$60 million. In DoD funding terms, that's pocket change.
To my mind, the more amazing thing is how fast the Navy got the systems involved modified to track and kill a target the weapons weren't originally designed for. Talk about agile development!
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Mostly correct, and congratulations on your independent discovery of some important bits of orbital mechanics through simulation, btw, that's pretty neat.
To be more specific: the transfer orbit is an ellipse (as are all orbits. Circles are just ellipses with an eccentricity of 0), which is similar to an egg, but more symmetric.
And you are completely correct about the important bit: Any delta-v burn performed as an impulse (as in, short duration, like an OMS burn or an explosion. Electric propulsion has more complicated rules) will change the orbit, and the new orbit always* passes through the point at which the burn was performed.
*except escape trajectories or certain (N>2)-body problems, but neither of those are really orbits, and they're not particularly relevant in the case under discussion.
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I suggest you try it. I actually cooked spaghetti in a brown paper bag placed in a fire while in boy scouts. Pretty neat actually.
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So what lies were told?
Was there a sat in orbit? - Confirmed something in orbit by outside observers
Was this a billion dollar spy sat or just left over junk planned for target practice?
Was this a known bad launch vehicle just tossed up as a target?
Was this an old sat intentionally moved to this lower orbit to use as a target?
Was it hit by the missile or was this all theater?
Did the sat have a self destruct and the missile mis it by a mile like one of the former tests?
Was this some show to cover some stranger event such as launching to orbit from sea?
They made a show of this for a reason!!!
[tin foil hat = off]