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US To Shoot Down Dying Satellite
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.'"
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.
todo - The developer's equivalent of confession: "Forgive me Father, for I have sinned..."
It seems to me that there's no real reason to "shoot down" this satellite, except as a test/demonstration of our ability to shoot down satellites (not necessarily our own)...
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~ |rip/\/\aster /\/\onkey
The reson we are doing this is obvious - to demonstrate to the world (and the Chinese) that was have functional ASAT capability.
This space available.
I'm no rocket-scientist, but one could argue the logistics (and subsequent pricetag) of capturing and redeploying a satellite are far, far greater than simply blowing it up. Doubly so when it is in such a decayed orbit.
Yes, but then you also need to put in a bunch of safe-guards against someone figuring out the triggering mechanism and simply blowing all of our satellites up. The problem with that is the more systems and failsafes you add, the more complex the system becomes. Invariably this results in the weight of the total payload increasing, which is a big factor in getting things to orbit in the first place. Plus it creates more areas for error, such as a controlling CPU not functioning, rendering the satellite useless.
Not even remotely similar to the Chinese test. The chinese satellite was in a useful orbit (emphasis on was).
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.
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.
Scott
He's getting rather old, but he's a good mouse.
That's probably unlikely. Keep in mind that a higher orbit requires more than just altitude, it also requires angular velocity. The explosion would have to impart enough kinetic energy to not just overcome the gravitational potential to reach the altitude of other sats, but also to impart the necessary angular velocity about the earth.
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.
I thought it was obvious, but none of the posters so far seem to have picked up on it. This is a further test of the ballistic missile defense program we've been spending $$$ for the last decade. In particular, the SM-3 Aegis Missile Defense System. One of the bonuses is this will be testing the missile under less strictly defined conditions.
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.
For a supposedly technical site, it seems very few Slashdotters are familiar with the tecnichal issues - or even bother to try. Rants before facts seems to be the motto.
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".
With a boiling point of 114C, I'd imagine the bulk of the hydrazine would be gone well before the thing hit the ground. This is about destroying whatever's on the satellite and showing off ASAT capability.
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.
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...)
Well, there's a difference between shooting a missile at a sattelite to test the missile, and shooting a missile at a sattelite thats going to fall in someone's backyard if they don't... Also a big difference in that they're actually trying to find a solution as to not have 127041702140 debris in space...
So yeah...err..totally different (and i'm not American, so I'm not defending my own nation or anything).
and
if the radio is dead (like on this current spy sat), it wont get the self-destruct signal
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...
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.
That satellite's anti-missile technology is as dead and unresponsive as the rest of that bird. This is simple target practice. Blow the hydrazine tank, try to break the mirror and open up all the aluminum to expose PCBs. Should be fun to watch, and people will be watching and waiting with telescopes to see the results. Cool!
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.
The force of the explosion can not put any part of the debris into a higher circular orbit. The debris may go into an elliptical orbit that has a much higher apogee, but perigee will be at the same altitude that the collision takes place. To get into higher circular orbit would require a corrective impulse at apogee. This is true for all of the debris that continues to orbit. Therefore, that debris will on each orbit pass through relatively thick atmosphere, and suffer the eventual consequence of de-orbit. In fact, since the surface area of the debris is likely to be much larger than that of the satellite, it should be a rapid de-orbit.
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