US To Shoot Down Dying Satellite 429
A user writes "US officials say that the Pentagon is planning to shoot down a broken spy satellite expected to hit the Earth in early March. We discussed the device's decaying orbit late last month. The Associated Press has learned that the option preferred by the Bush administration will be to fire a missile from a U.S. Navy cruiser, and shoot down the satellite before it enters Earth's atmosphere. 'A key concern ... was the debris created by Chinese satellite's destruction -- and that will also be a focus now, as the U.S. determines exactly when and under what circumstances to shoot down its errant satellite. The military will have to choose a time and a location that will avoid to the greatest degree any damage to other satellites in the sky. Also, there is the possibility that large pieces could remain, and either stay in orbit where they can collide with other satellites or possibly fall to Earth.'"
Our secrets are worth more than your secrets! (Score:5, Insightful)
Is this really anything else? The US is willing to protect it's secrets, China was trying to ensure they could protect theirs. Both are sovereign nations with the technology and ability to make these decisions.
The only way issues like this will ever be resolved is by allowing some intra-national body to have either approval or veto powers, but nobody wants to be told what they can/can't do.
Ulterior motive? (Score:5, Insightful)
Comment removed (Score:3, Insightful)
Re:Ulterior motive? (Score:5, Insightful)
That, or there's some technology on the satellite that they don't want to risk falling (literally) into the hands of another country.
Re:Ulterior motive? (Score:4, Insightful)
Re:Oh bullshit. (Score:5, Insightful)
It's a brand new spy satellite that failed on deployment. It's chock full of the highest tech we could stuff in it.
I'd blow it up too if it was mine, there's a crapload of technology that even after reentry would be of HUGE value to many many people on this planet.
Re:Ulterior motive? (Score:5, Insightful)
A. If push comes to shove they want to be able to shoot down emeny satellites.
B. They don't want the technology/information going to an other countries hands.
C. To show that we can, prevent other people from knocking out our own satellites.
Re:Controlled de-orbit? (Score:2, Insightful)
Re:Oh bullshit. (Score:3, Insightful)
Or, we have a self-destuct system and one of it's requirements is communication with ground.
In that case I guess I'd have liked to of seen some built in structural weakness. Some sort of failsafe so that if the satellite were to re-enter the atmosphere and begin to burn up, some ignitable material would ensure a thorough burn/destruction of the entire satellite. Kinda like explosive bolts only not limited to the bolt mold.
Re:let this be a lesson to NASA/JPL (whoever) (Score:2, Insightful)
Re:Oh bullshit. (Score:4, Insightful)
Re:Not the same as Chinese Test (Score:1, Insightful)
The American bird is already in a severely decayed orbit, and the pentagon isn't planning a shootdown until the shuttle has landed so that will mean it will even be decayed that much more.
The debris field left over after the interception will be in the same usless/decaying orbit; bouncing off the upper reaches of the atmosphere. The debris field will de-orbit in the same manner as the intact sattelite, but any large/dangerous pieces are much more likely NOT to make it to the ground.
Re:Controlled de-orbit? (Score:3, Insightful)
The problem with your idea comes down to it being far too complex of a process for the intended result. Launching a rocket to match up with another satellite is much more difficult than in sounds. The bottom line is that it's much easier to get close to something and explode than it is to dock with it and then try to control. In the end you get the same result so you might as well go with the cheaper and easier solution.
Re:Target practice or....? (Score:3, Insightful)
Re:Our secrets are worth more than your secrets! (Score:5, Insightful)
That may be the actual thought process at the Pentagon, but there is actually a sound justification for shooting down this satellite: TFA says there is a 1 percent chance debris could hit a populated area. That is well above the danger threshold NASA, etc. allow when choosing where to perform a controlled deorbit. 1 percent doesn't seem like a lot, until you realize how many satellites are up there, and they all must come down eventually.
Even if safety weren't a genuine concern, it would still be acceptable to shoot down this particular satellite, in my uninformed opinion. I believe this because it's already in a decaying orbit that will bring it down within two months. Any debris created by the explosion will be in a similar or slightly higher orbit, and will also decay to GLO (ground-level orbit) in a reasonably short time. The satellite the Chinese shot down was in a much higher orbit, and that debris is likely to stay up for *hundreds* of years, IIRC. If they had shot down a satellite in a similar orbit as this, there wouldn't be a stink about the debris, only about the naked attempt at weaponizing space.
Re:Our secrets are worth more than your secrets! (Score:5, Insightful)
To be fair, the space junk isn't equivalent -- the junk from a satellite that's about to reenter will also reenter promptly, whereas the junk from a satellite in a high orbit will remain in a high orbit. The impact won't actually alter the orbital parameters of the junk as much as you might expect; nearly all of it will reenter promptly, and I'd be surprised if any of it managed to get high enough to present a danger to other satellites (the satellite in question is well below normal operating altitudes).
Of course, I'm not trying to say the US isn't guilty of hypocrisy -- just that this case isn't as bad as you make it out to be.
Re:Ulterior motive? (Score:3, Insightful)
And, we can (sorta) choose where the pieces come down, instead of relying on mere chance. My guess is they'll bring it down over the ocean.
Re:Target practice or....? (Score:5, Insightful)
The US military is probably aware of the max velocity of debris from their different ordinance. As much as the US administration is full of morons, the physicists designing the ordinance and planning stuff like this are quite competent.
Ballistic Missile Defense (Score:5, Insightful)
The program has been in the development and test phase since about 2000, and undergoing tests of increasing difficulty, but always under predefined conditions. The tests are also expensive to orchestrate, typically involving several naval vessels, and a lot of ground support from both the navy and contractors, a lot of documentation, and a target missile that itself probably costs several million dollars. Here they've got a target that won't behave as predictably and costs nothing (well sort of...It's a spy satellite that failed to reach the proper orbit). I'm not sure they even know when or where it will come down yet.
This isn't necessarily a good demonstration of our ability to shoot down satellites. The officially released specs say it has a maximum altitude of 160 km. Most satellites orbit higher than that. However, the actual performance is classified and probably somewhat greater.
It's also not something new. We tested anti-satellite weapons in the 80's, although those are now past their shelf life and the response time was slow. In the 60's we developed a system called Nike Zeus that had an altitude ceiling of about 300 km. It wasn't accurate enough to directly hit a ballistic missile or satellite to achieve a kinetic kill like the SM-3 does, but with a 40 kiloton nuclear warhead, that didn't much matter. It was never tested with a live warhead and it would have been messy to use (damages anything else nearby, terrible EM interference on the ground, etc), but it was something.
Once gain - tinfoil over facts (Score:5, Insightful)
This is very unlikely to add to the space junk problem - because this bird is in a decaying orbit. You further reduce the chances by waiting as late as possible (when the bird has been greatly slowed). You further reduce the risks by arranging your intercept geometry such that few (or no) pieces are boosted towards or into stable orbits.
It's not nearly as simple as "oh n0es, bl0w1ng stuffs up 1n spac3 m3ans mor3 spac3 junk !!11!!!1111!!111".
no, it's not the hydrazine (Score:5, Insightful)
As for the PR damage of killing whoever comes across the fuel, after the whole Iraq war thing, I think it can be conclusively and uncontroversially stated that one thing the Bush administration doesn't give two shits about is bad PR.
Re:Ulterior motive? (Score:2, Insightful)
Remember when the F-117 was shot down in the Balkans? Even though the airplane was broken, I can guarantee you that the Russians and Chinese were very interested in examining the debris. You can learn a lot from a busted piece of machinery.
Re:Ulterior motive? (Score:1, Insightful)
Re:Our secrets are worth more than your secrets! (Score:3, Insightful)
What goes up must come down, eh?
Nope.
It depends entirely on the radius of the orbit, the orbital velocity, and the amount of upper atmosphere remaining at that altitude. If the orbit is good and the drag nil, it'll stay up there. Or at least that's how orbital mechanics worked when I was a kid.
Re:Our reasons are better. (Score:3, Insightful)
As opposed to the US, which has brought so much good to the world lately, I guess.
(By the way, China is as communist as the US is a free market...)
Re:Hypocrites (Score:3, Insightful)
So yeah...err..totally different (and i'm not American, so I'm not defending my own nation or anything).
Re:Our secrets are worth more than your secrets! (Score:5, Insightful)
Such as telling certain countries they are not allowed to have nuclear weapons while allowing, and even encouraging, others to do so. Or telling certain countries they cannot have wmds in general and then invading that country to prove they don't have any. Or did you mean not trading with a country until it changes its political climate?
You mean a world dictatorship telling soverign nations what they are permitted to do like that, right?
Re:Our secrets are worth more than your secrets! (Score:5, Insightful)
Re:let this be a lesson to NASA/JPL (whoever) (Score:1, Insightful)
and
The solution to both is pretty obvious...set it to *auto* self-destruct if it looses contact with our ground stations (which send an encrypted "stay-alive" signal).
Then, if the radio fails, it self destructs automatically after say two weeks. There would also not be any kill signal for our enemies to crack and send... they would have to stop us from transmitting our "stay-alive" signal which is obviously much harder since it can be done from anywhere in the world where we have sat transmitters.
Just a thought...
Still dangerous (Score:5, Insightful)
Letting the satellite re-enter atmosphere unbroken would be the only way to make sure it does NOT create a debris field.
A satellite is not an airplane, there's no way to "shoot" it down. Breaking it in pieces will not bring it down, it's atmospheric drag that's doing it. All the Pentagon is doing is trying to make sure that it breaks down into pieces small enough to protect their military secrets.
By blowing up the satellite with a missile they have no control on how it's going to break, all they can do is estimate on the most probable breaking patterns. They cannot be sure that the remaining pieces will be of such sizes and shapes to re-enter the atmosphere in a predictable manner and time.
There is still the possibility that some of the largest fragments will hit some populated area. The fuel tanks, which are compact and very strongly built, will have a rather good chance of surviving, and reaching the earth's surface still containing some of that extremely toxic hydrazine (so toxic that a drop can kill a person). Besides, the explosion will inevitably send some fragments into a higher orbit, and possibly damage other satellites.
Blowing up a decaying satellite with a missile is, IMHO, the stupidest thing to do, and I have been an engineer working with satellite control systems for nearly 24 years by now.
Re:Still dangerous (Score:2, Insightful)
Re:Target practice or....? (Score:3, Insightful)
Re:Still dangerous (Score:3, Insightful)
Land Shuttle Atlantis through LEO debris? (Score:2, Insightful)
Blowing up a decaying satellite with a missile is, IMHO, the stupidest thing to do, and I have been an engineer working with satellite control systems for nearly 24 years by now.
I'm glad someone in the field agrees with me on this.Still it might keep some bad stuff out of the hands of bad guys...And it might be pretty to watch over a wider area. It. reminds me of a farside cartoon with martians watching mushroom clouds over earth going "OOOOhh, ahhhhh!"
I'm not a rocket scientist but I don't think this is a bright idea. The fact that Bush's security advisers say it is a good idea is hardly a resounding vote of confidence.
Re:Target practice or....? (Score:3, Insightful)
Re:Still dangerous without the shot? (Score:3, Insightful)
Re:Still dangerous (Score:3, Insightful)
Firstly, the energy to deorbit a satellite is not the same as that required to put it up, returning space capsules and decommissioned satilites require very small burns with their thrusters to in effect transfer the satellite to an elliptic transfer orbit that intersects earth's atmosphere around the large ocean that it is to be put into. The Apollo service module weighed slightly less than the Delta-IV rocket's maximum load to LEO (24 tonnes) and was able to perform a trans-earth injection burn and was able to bring a multi tonne capsule home from THE FRIGGING MOON while also providing life support, electricity and communications systems. Earth from geosynchronous can be done by satellite thrusters when a parking orbit isn't acceptable. Earth from LEO requires nothing more than a computerised bottle rocket.
Secondly, even if deorbiting required the same energy as orbiting, 20 tons of solidified RDX/PETN mix (which can by easily lifted to the right orbit with a Titan IV or Atlas V rocket) can release far more energy than any rocket ever built, not quite what the GP was suggesting, but non-nuclear none the less.
Thirdly, even in the ludicrous hypothetical situation where it did require a nuclear weapon to provide the energy it wouldn't matter since the US government has plenty of them currently mounted on large and pinpoint accurate space vehicles that it would use if required to despite the space weapons treaty.
Fourthly, you've got to seriously think about posting anonymously next time you say someone is wrong in such as rude way while showing some serious misunderstandings of the physics yourself. And is Derek Lyons your real name? If so you really should think of some anonymity if you want to act like a jerk. Slashdot has always been a great place for semi-informed people to post their ideas just like the grandparent and parent did. There are probably people here involved in rocketry, astrophysics, guidance systems and such, but not enough to make this discussion good. I've done some physics in university and read up a bit about the subject and that's all we really expect from a person who is part of a slashdot discussion. If the USAF asked me to plan the mission in question, I'd tell them that I'm not qualified, but in slashdot I can give my 2 cents. If you don't like it then maybe you should start reading peer-reviewed journals or something.