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US To Shoot Down Dying Satellite

Posted by Zonk on from the we-who-may-be-about-to-reenter-orbit-salute-you dept.

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.'"

73 of 429 comments (clear)

  1. Our secrets are worth more than your secrets! by stevedcc · · Score: 5, Insightful
    "We consider our secrets to be worth space junk, but your security not to be".

    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..."
    1. Re:Our secrets are worth more than your secrets! by crymeph0 · · Score: 4, 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.

      --
      It should be illegal to say that freedom of speech should be limited.
    2. Re:Our secrets are worth more than your secrets! by evanbd · · 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.

    3. Re:Our secrets are worth more than your secrets! by Nefarious+Wheel · · Score: 2, Insightful
      until you realize how many satellites are up there, and they all must come down eventually.

      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.

      --
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    4. Re:Our secrets are worth more than your secrets! by smooth+wombat · · Score: 4, Insightful
      Yes, all we need is a world dictatorship to tell sovereign nations what they are permitted to do.


      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?

      --
      We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
    5. Re:Our secrets are worth more than your secrets! by amorsen · · Score: 4, Insightful

      I didn't mean "must" in the "great hand of physics will pull the satellite to its inevitable doom" sense, but rather in the "we intentionally deorbit all our satellites after their useful life is over to avoid filling the skies with debris" sense. And how exactly does that happen? Geostationary satellites get pushed slightly higher so they don't take up space in the geostationary orbit, but they never bring enough fuel to be able to get back to Earth.

      And even without intentionally deorbiting them, most satellites experience enough atmospheric drag (i.e. not 'nil') to bring them down in tens to hundreds of years - not a legacy you'd like to leave your grandchildren. Again, wrong for geostationary (and lots of other orbits).
      --
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  2. Target practice or....? by link5280 · · Score: 5, Interesting

    Since this is a severely decayed orbit I would suspect most debris to reenter within the same timeframe or shortly thereafter, 1-2 weeks. I also doubt it will create any debris fields in a useful orbit. Anyway, the only reason the military would do this in the first place is to ensure a complete destruction of the spacecraft. Break it up into small pieces beforehand and the reentry will take care of the rest. Otherwise, why bother! Or target practice?

    --
    Iraq billions
    1. Re:Target practice or....? by p0tat03 · · Score: 5, Interesting

      A bit of both I suppose. It's not every day you get to do a live-fire exercise of your satellite-attacking technologies... Not to mention it's not every day you get a real live test of just how good your satellite's anti-missile technologies are! Either way somebody in the military wins :P

      Big chunks will no doubt re-enter the atmosphere relatively quickly, and they should be small enough that they will burn up completely in upon re-entry, which I think was the whole point of this exercise...

    2. Re:Target practice or....? by Sen.NullProcPntr · · Score: 4, Interesting

      Big chunks will no doubt re-enter the atmosphere relatively quickly, and they should be small enough that they will burn up completely in upon re-entry, which I think was the whole point of this exercise... What about the force of the explosion? With no air resistance isn't just as likely that some pieces (of both the satellite and the missile) will end up in higher orbit thus the concern for collision with other satellites.
    3. Re:Target practice or....? by gnick · · Score: 2, Insightful

      Or target practice? Don't underestimate the value of target practice. Shooting down a satellite is no simple matter. The Chinese engineers decided that they couldn't just hit one with a missile, so they sent up a missile capable of firing a separate payload once it got close enough. I'm sure the US would love an excuse to try out a satellite killer. And, since it's been made clear what a hazard this thing could be if it falls to earth, they can try out their new toy AND protect the planet from their defunct satellite.
      --
      He's getting rather old, but he's a good mouse.
    4. Re:Target practice or....? by Trails · · Score: 5, Insightful

      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.

    5. Re:Target practice or....? by imipak · · Score: 3, Funny

      I say we launch it into orbit, and nuke it from the surface. It's the only way to be sure.

    6. Re:Target practice or....? by Anonymous Coward · · Score: 5, Informative

      Short answer: No

      Longer answer: The orbit of a satellite can be determined by the position and the velocity at any time. Orbits are changed by changing the velocity of a satellite, but the old and new orbits will continue to intersect at the point where the velocity was changed.

      Changing to a higher orbit will require two changes in velocity and uses a transfer orbit that intersects both orbits. One velocity change puts the satellite into the transfer orbit and one velocity change puts it into the final orbit. Usually, the two velocity changes are at opposite sides of the transfer orbit (half an orbit period apart).

      I assume that this will use a warhead instead of a rocket motor for a single change of velocity, but there will only be one change of velocity. If the intercept takes place at lowest point of the current orbit then any debris will be in an orbit that will return the debris to the point of intercept. If it is already brushing the atmosphere then reentry is inevitable and the time to reentry will only depend on the ratio of the mass to air drag of the object (small heavy objects will stay in orbit longer).

      Normal precautions of staying out of the temporary orbits of the debris does apply.

      _Richard

    7. Re:Target practice or....? by Jeremi · · Score: 4, Funny
      That's nice that you know the volume of a circle


      Just to be a smartass, I have to point out that the volume of a circle is zero, not pi*r^2.

      --


      I don't care if it's 90,000 hectares. That lake was not my doing.
    8. Re:Target practice or....? by kabloie · · Score: 2, Insightful

      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!

    9. Re:Target practice or....? by drerwk · · Score: 2, Insightful

      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.

    10. Re:Target practice or....? by ceroklis · · Score: 2, Interesting

      BTW I and the OP should have said "disk" instead of "circle", but it is not uncommon to say the later when you mean the former. Mathematicians are generally clever enough to understand the context and not quibble over silly details.

  3. Ulterior motive? by TripMaster+Monkey · · Score: 4, Insightful

    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)...

    --
    ____

    ~ |rip/\/\aster /\/\onkey

    1. Re:Ulterior motive? by Iphtashu+Fitz · · Score: 4, Insightful

      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

      That, or there's some technology on the satellite that they don't want to risk falling (literally) into the hands of another country.

    2. Re:Ulterior motive? by stevedcc · · Score: 3, Insightful

      It's a spy satellite and it's so big that some of it's gonna crash. What if that's over Iran/N Korea/China? You think the US wants them picking apart the remains of classified technology? They have a reason, it's just not necessarily any better than China's logic in testing their ability to destroy satellites (protect themselves from other people's spy satellites). Unless you think that the US's reason is better because it's the US, and China's worse, because it's China.

      --
      todo - The developer's equivalent of confession: "Forgive me Father, for I have sinned..."
    3. Re:Ulterior motive? by jellomizer · · Score: 4, Insightful

      I would say it is a kill two birds with one stone.
      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.

      --
      If something is so important that you feel the need to post it on the internet... It probably isn't that important.
    4. Re:Ulterior motive? by TripMaster+Monkey · · Score: 5, Interesting
      From a related story (emphasis mine):

      The orbit of Solar Max, a 5,000-pound satellite that collected information on solar flares for nine years, has deteriorated to the point that the spacecraft should crash back to earth late this week, the space agency said today.

      Most of the craft will burn up in the atmosphere, but about a dozen pieces of three to five pounds each, plus one piece of about 100 pounds, are expected to come back down to earth. The debris could fall anywhere on earth from 28 degrees north to 28 degrees south of the Equator.

      And from TFA (again, emphasis mine):

      It is not known where the satellite will hit. But officials familiar with the situation say about half of the 5,000-pound spacecraft is expected to survive its blazing descent through the atmosphere and will scatter debris -- some of it potentially hazardous -- over several hundred miles.

      It doesn't seem as if "shooting down" the satellite is really going to cause much more damage than re-entry and impact will...for this reason, my money's on either target practice for our benefit, or, more likely, a not-so-subtle demonstration of our space superiority.
      --
      ____

      ~ |rip/\/\aster /\/\onkey

    5. Re:Ulterior motive? by YrWrstNtmr · · Score: 2, Insightful

      It doesn't seem as if "shooting down" the satellite is really going to cause much more damage than re-entry and impact will...for this reason, my money's on either target practice for our benefit, or, more likely, a not-so-subtle demonstration of our space superiority.

      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.

    6. Re:Ulterior motive? by icebrain · · Score: 2, Insightful

      Just because it broke doesn't mean you can't learn useful information from it. Most likely, the failure was something small (broken wire, software bug, dead battery, something of that nature), so assuming the hardware survives reentry and lands somewhere accessible, there's a very good chance analysts would get lots of information.

      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.

      --
      The meek may inherit the earth, but the strong shall take the stars.
    7. Re:Ulterior motive? by AJWM · · Score: 4, Interesting

      You can learn a lot from a busted piece of machinery.

      Heh, or not. One of the things Britain did during WW II was to leave bits of busted machinery (electronics) that not only never worked, but were designed to be deliberately misleading, at the occasional aircraft crash site in German-occupied territory. The idea was to keep German radar scientists, etc, busy chasing down wrong paths if/when they recovered the equipment. (Which they did; recovering any kind of radar-related gear from Allied aircraft was a high priority for them.)

      --
      -- Alastair
    8. Re:Ulterior motive? by robfoo · · Score: 2, Funny

      I would say it is a kill two birds with one stone.
      A..
      B..
      C..

      uh, I think that's three birds.

  4. Oh bullshit. by Jafafa+Hots · · Score: 2, Insightful
    Satellites have been falling ever since we started putting them up, its no real threat.

    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.
    1. Re:Oh bullshit. by scheme · · Score: 5, Interesting

      Satellites have been falling ever since we started putting them up, its no real threat.

      The reson we are doing this is obvious - to demonstrate to the world (and the Chinese) that was have functional ASAT capability.

      I think the reason is more because various agencies are worried that the satellite will end up falling in someplace while Russia or China and the intact pieces will give these countries examples to reverse engineer or clues as to US capabilities. I believe the satellite is supposed to be the newest generation of spy sats so it's probably full of interesting little tech.

      --
      "When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it
    2. Re:Oh bullshit. by Lumpy · · Score: 4, Insightful

      Bullshit on your bullshit.

      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.

      --
      Do not look at laser with remaining good eye.
    3. Re:Oh bullshit. by Jafafa+Hots · · Score: 5, Funny

      Well, that's all well and good, but YOU read the fucking ARTICLE.

      --
      This space available.
    4. Re:Oh bullshit. by malakai · · Score: 2, Insightful

      This is my thoughts as well. What scares/embarsses me is that we seem to have not thought of this ahead of time and so there is no built-in self destruct capability.

      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.

      --
      -Malakai
      A Dragon Lives in my Garage
    5. Re:Oh bullshit. by AvitarX · · Score: 4, Insightful

      Self destruct systems have mass and volume. That is a very tight resource on something sent into space.

      --
      Wow, sent an e-mail as suggested when clicking on "use classic" banner, and got a fast response that addressed my msg
    6. Re:Oh bullshit. by eclectro · · Score: 2, Funny

      there's a crapload of technology that even after reentry would be of HUGE value to many many people on this planet. Including all those who would want to see if it could run Linux.
      --
      Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
  5. Hey, how about making a film about this?? by sholdowa · · Score: 2, Funny

    We could send up a group of octogenarian actors in a shuttle... whadya mean it's already been done!

  6. Simple enough by Nushio · · Score: 2, Funny

    Host a tournament based on Missile Commando or any game similar to that.

    The Winner gets to choose when and where to shoot the missle :)

    --
    Check out Unsealed: Whispers of Wisdom! http://unsealed.k3rnel.net It's an action-RPG about Open Sourcerers.
  7. I can imagine that conversation by techpawn · · Score: 2, Funny

    Military: Sir, there is a satellite and it's slowly falling to earth
    Bush: 'kay
    Military: It poses no real threat, it will probably burn up on reentry...
    Bush:'Kay
    Military: It was a secret spy satellite...
    Bush:What? Spy?
    Military:It will look real pretty if we blow it up sir...
    Bush: OooOooOoo Pretty... Kay, where do I sign to see the pretty boom boom?!

    --
    Ask not what you can do for your country. Ask what your country did to you
  8. Not the same as Chinese Test by usul294 · · Score: 5, Interesting

    This satellite was never able to communicate to the ground. Its orbit was never finished off, which is why it decayed so much as to reenter the atmosphere after 15 months after launch. If they shoot this satellite down, the pieces will still almost all re-enter. The main reason for shooting it down, more than likely is to make sure the fuel doesn't make it past the very upper atmosphere, as well as to ensure that no one unscrupulous gets any technology. The kinetic energy delivered by the missile won't overcome the energy needed to kick the debris back into orbit, so there won't be a debris field.

  9. Controlled de-orbit? by Dr_Banzai · · Score: 2, Interesting

    If they're going to the trouble of launching a rocket to intercept the satellite, why don't they build a small booster which could attach to the satellite and perform a controlled de-orbit? This would allow them to choose the point of re-entry to protect whatever secrets may be on board.

    There is far too much space junk up there already. Blowing the satellite into a million pieces doesn't seem like the smartest thing to do. I suspect the US simply wants to demonstrate and test its own anti-satellite system.

    1. Re:Controlled de-orbit? by Domint · · Score: 2, Insightful

      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.

    2. Re:Controlled de-orbit? by schematix · · Score: 2, Insightful
      If they're going to the trouble of launching a rocket to intercept the satellite, why don't they build a small booster which could attach to the satellite and perform a controlled de-orbit? This would allow them to choose the point of re-entry to protect whatever secrets may be on board.

      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
    3. Re:Controlled de-orbit? by Oktober+Sunset · · Score: 2, Funny

      Ohhhh, they could launch it from a hollowed out volcano and it could capture space capsules too and hold the astronauts hostage.

      --
      What if Tetris was invented by Nazis?
  10. let this be a lesson to NASA/JPL (whoever) by FudRucker · · Score: 3, Interesting

    next time they build a satellite it would be a good idea to put a self destruct in it that can be activated remotely, cheaper and more reliable than shooting missiles at it...

    --
    Politics is Treachery, Religion is Brainwashing
    1. Re:let this be a lesson to NASA/JPL (whoever) by stevedcc · · Score: 3, Informative

      next time they build a satellite it would be a good idea to put a self destruct in it that can be activated remotely, cheaper and more reliable than shooting missiles at it...

      Unless of course, the satellite stopped working because it's computer is bust. Then you'd have a big lump of explosives rolling around in space, and no control over it.

      --
      todo - The developer's equivalent of confession: "Forgive me Father, for I have sinned..."
    2. Re:let this be a lesson to NASA/JPL (whoever) by Domint · · Score: 2, Insightful

      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.

    3. Re:let this be a lesson to NASA/JPL (whoever) by moderatorrater · · Score: 2, Funny

      Great idea. Then the smart ass 12 year old Polish kid's going to use a TV remote to blow it up. Aside from the added weight and technical complexity that this would add to the satellite, if those codes get hacked it's millions if not billions of dollars down the toilet. Maybe more, if they detonated the satellites at a strategically advantageous time.

    4. Re:let this be a lesson to NASA/JPL (whoever) by tomhath · · Score: 2, Informative

      Self-destruct would be good, assuming they can communicate with the satellite. But if they could communicate with it, they would've commanded it to make a controlled de-orbit.

  11. They are spinning the media with a scare story by Ellis+D.+Tripp · · Score: 2, Interesting

    about the hydrazine fuel onboard, and the hazard it would pose to anyone on the ground, as if the fuel tanks would survive the breakup and atmospheric heating of the re-entry.

    Looks like a great chance for the Bush regime to pull off an ASAT test, with a ready-made cover story to deflect blame for all the space junk it will create.

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  12. Cost Effectiveness. by gandhi_2 · · Score: 5, Funny
    Since the Chinese have proven they can do this, it's reasonable to assume they can do it cheaper. Maybe they pentagon could outsource this satellite shoot-down.

    You know, if the pentagon REALLY wanted to come across as bad ass, they wouldn't have told anyone it was a bad satellite. Then we could show the world we'll shoot down our own satellites just cause we can. Like a diplomatic "Don't you know i'm locco, esse?"

    --
    THL phish sticks
  13. Re:Incompetent by Domint · · Score: 4, Informative

    Why not use those thrusters to drop it into the ocean at a planned location with the Navy there to pick it up on splashdown.

    Kind of hard to do that when the master CPU fails on boot-up, which is the whole reason why something needs to be done about it. It is literally out of control.

  14. Shooting it down? by sm62704 · · Score: 4, Funny

    It's already coming down, isn't it? Wouldn';t they be shooting it UP?

    That makes a better headline anyway, "US To Shoot Up".

    --
    mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
  15. Re:Incompetent by QuantumRiff · · Score: 4, Informative

    Did you even read the linked article? The satellite has lost all contact. It has rocket fuel, yes, but there is no way to communicate with it and tell it to fire the thrusters. As for the Navy picking it up, that is logistically a pain in the ass. Even when you can control the splashdown, you can get it to within a few hundred square miles. (lots of variance in air temperature, density, and wind) By the time a boat or helicopter could get to the actual crash site, it would be several thousand feet below the surface of the water. (which i'm sure the govt prefers...) Rocket boosters they pick up, but only because they are specifically designed to float.

    --

    What are we going to do tonight Brain?
  16. Re:Incompetent by ddusza · · Score: 5, Funny

    Yes sir, can you try typing Ctrl-Alt-Delete? Oh, that didn't work? Hmmmm, can you try turning the power off and back on again? No? Well, I'm afraid we are just going to (trouble)shoot it remotely from one of our Tech Support Cruisers.... The NEW world of Tech Support

    --
    Don't fear the penguins
  17. In other news... Dead Horse Mercilessly Beaten by t33jster · · Score: 2, Funny

    I must be missing something. The satellite is FALLING. We're going to shoot it DOWN?!?!

    --
    Take off every 'sig' for great justice.
  18. Re:ASAT by cmowire · · Score: 2, Interesting

    The mods to hit a non-manuvering target are probably not that bad. Besides, The Aegis / SM system is already being upgraded to knock out ballistic missiles. Plus, the test results there are much better than the results from the national missile defense system.

    Both the original ASAT system and the Aegis are only useful for low orbiting targets. So it's probably more useful to have it as part of a theater defense setup more than something you need to have enough warning to launch an F-15 at.

    But, yah, the smart money's on it being a demonstration to Russia and China.

    --
    Gentoo Sucks
  19. It's far less sinister than that... by Bryan+Gividen · · Score: 2

    He's not worried about rocket fuel or demonstrating power. He's looking at the countdown on his presidency and he is realizing, "Hmm... I only have 11 months to blow up something again... let's do it in space this time..." It's the international equivalent of putting an M2 in the toilet.

  20. Ballistic Missile Defense by iamlucky13 · · Score: 5, Insightful

    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.

  21. Once gain - tinfoil over facts by DerekLyons · · Score: 4, Insightful

    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".

  22. no, it's not the hydrazine by Reality+Master+201 · · Score: 4, Insightful

    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.

  23. I often wondered by kellyb9 · · Score: 4, Funny

    I've often wondered what aliens might think if they were to visit earth and see us shooting missles at our own satellites as means of getting them down. On one side of the coin, we might look really badass.

  24. China's debris to remain for thousands of years... by KH2002 · · Score: 5, Informative

    The satellite the Chinese shot down was in a much higher orbit, and that debris is likely to stay up for *hundreds* of years... It's worse than that -- according to MIT space security expert Geoffrey Forden, "China's debris will be in orbit for thousands of years (and I mean that literally). ... [The US shoot-down] would create a debris field but no where near the sort of debris catastrophe that China created last year."

    The two shoot-downs are not equivalent, which of course won't prevent agenda-driven comparisons...

  25. Re:Our reasons are better. by msuarezalvarez · · Score: 2, 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...)

  26. Re:Hypocrites by Shados · · Score: 2, Insightful

    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).

  27. Major differences by WindBourne · · Score: 2, Interesting
    1. The solar max does not have much in way of secret equipment. Nearly all is known. OTH, the spy bird is highly secret (though it appears that a number of leaks have been occurring over the last couple of decades).
    2. The solar max is STILL UNDER CONTROL. OTH, the spy bird is not. There is no way to tell it to plunge into the atmosphere at such and such a place and such and such an angle.
    Keep in mind, that America (as does Russia, China, UK, France, and others) de-orbits spy sats regularly. There have been some that have also been put into much higher orbits due to issues with spreading contaminates (read radiation).
    --
    I prefer the "u" in honour as it seems to be missing these days.
  28. Still dangerous by mangu · · Score: 5, Insightful

    [The US shoot-down] would create a debris field but no where near the sort of debris catastrophe that China created last year

    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.

    1. Re:Still dangerous by Sean+Riordan · · Score: 2, Insightful

      I don't buy the can't be shot down point. It it were to be hit (hard) from the front relative to it velocity vector there would be enough loss of momentum to cause it to come down. I would think that would qualify as shot down, though not in a Hollywood like dramatic splash down kind of way. Effective nonetheless. Calculated correctly this should allow some control of where the bits would fall. The problem I think would be getting the missile in line with the angle of attack needed while retaining enough oomph to cause a large loss of momentum on the part of the space vehicle in question.

      --
      Sig? What if I prefer Glock?
    2. Re:Still dangerous by mangu · · Score: 3, Informative

      It it were to be hit (hard) from the front relative to it velocity vector there would be enough loss of momentum to cause it to come down

      Sure, but how hard can you hit? It's not as if it were hitting a stone wall, it's hitting an exploding missile, that is, a fire ball. It's travelling at close to 8000 meters, or five miles, per second.


      The densest parts, like batteries, fuel tanks, and possibly the main camera mirror, will go through that explosion ten times faster than a bullet. Do explosions stop bullets? Not unless it's precisely concentrated at the exact point. There is no way the explosion could transfer enough momentum to the densest parts to significantly affect their orbit.


      The flimsiest parts like, for instance, the solar panels, will be shredded to very small pieces by the explosion, of course, but those are exactly the parts that would burn first when entering the atmosphere.

    3. Re:Still dangerous by Sean+Riordan · · Score: 3, Insightful

      Exploding munitions wouldn't be optimum for hitting the vehicle IMHO as most of the energy is essentially wasted. Better to drive a mass into it around the center of mass/gravity I would think. Logistically a bitch, but far more effective than trying to leverage fireworks against orbital momentum. The idea isn't to blow it up, just to give it a shove in direct opposition to the forward motion to subtract out as much momentum as possible thereby making it fall out of orbit. Granted, since it appears the NRO owns the soon to be space junk there may be a reason to go for maximum carnage, but I don't see how explosives are going to be a useful solution. Better to control the impact point if the intent is to retain control of onboard goodies. Luckily that is also the best way to ensure safety of people at said impact point. Getting a significant mass in place to pull it off is likely unrealistic or at least prohibitively expensive.

      --
      Sig? What if I prefer Glock?
    4. Re:Still dangerous by SETIGuy · · Score: 3, Interesting

      Sure, but how hard can you hit? It's not as if it were hitting a stone wall, it's hitting an exploding missile, that is, a fire ball. It's travelling at close to 8000 meters, or five miles, per second. Trying to destroy a spacecraft with a fireball would be pretty stupid, and I doubt the U.S. military would be that stupid. What you want is a slowly expanding cloud of massive objects to intersect the satellite at high velocity. Lot's of explosives aren't necessary because you don't need to get the shrapnel to high velocity.

      Since you've got 8 km/s of orbital velocity and probably around 3 km/s on the interceptor, you're probably talking about 10 km/s at the intercept. The heat of vaporization of iron is 250 kJ/kg and this thing has a mass of 11 tons, so we can assume 2.7 GJ will do quite a number on this satellite. Sure, it's not made of iron, but you don't really need to liquify it to destroy it. Satellites are usually only built to survive launch stresses, not impacts.

      Anyhow at an impact velocity of 10 km/s 2.7 GJ would require a impactors with a total mass of 50 kg, probably in the form of lead or depleted uranium for compactness. To be thorough in your destruction, you probably want multiple small impactors, say 500 of them at 100 grams each. The total mass of the warhead depends upon how close you can get to the target. If you could be ensured a direct hit, 50kg would suffice. But it's likely that this won't be a direct hit, so you'll need to cover a larger area than the satellite itself.

      We'll assume the satellite projects an aspect of 600 square meters (say about 60 meters by 10 meters) and that our shot cloud covers a circular area. Once your impact parameter exceeds 14 meters your warhead size goes up as the square of the distance. At 25 meters, you need 160 kg. At 50 meters you need 650 kg. At 100 meters you need 2.6 tons. At a kilometer you need 260 tons.

      The only thing determined by the yield of the charge that scatters these impactors is the timing. How long before impact do you need to set it off and how accurate does your timing need to be? These are left as an exercise for the reader. If I were designing the thing I'd keep the scattering charge as small as possible. The bulk of the constraints are set by the trajectory. In a head on trajectory, there is nothing wrong with scattering the impactors 5 seconds or more before impact. For an interceptor that travels vertically, the maximum timing probably depends upon atmospheric properties.

      Given the geometry of the likely impacts, it is unlikely there would be significant amounts of ejecta inserted into long lasting orbits. The worst cases would be insertions into elliptical orbits, but they would circularize quickly at low altitude due to the low perigee. It should be possible to choose in impact point that will minimize risk to other vehicles.

      FWIW, I do not design space weaponry, and I do not know the actual capabilities of U.S. anti-satellite weaponry. I just know how to break things in a practical and sometimes dramatic manner.

      --
      Support SETI@home
    5. Re:Still dangerous by donscarletti · · Score: 2, Insightful

      Other than the fact that delivering that amount of energy in that small an area is roughly equivalent to a small nuclear weapon.... that's an excellent plan.

      Hint: This is what we call sarcasm. Your plan sucks and is based on utter and complete ignorance of science. You don't even have any common sense - you seem to not noticed that it takes a huge honkin' rocket to get it up there, which implies it takes a huge honkin' amount of energy to reverse that situation. You aren't even smart enough to know that you don't know - you state your ignorant opinion as though it was fact.

      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.

      --
      When Argumentum ad Hominem falls short, try Argumentum ad Matrem
  29. Re:Still dangerous without the shot? by mangu · · Score: 4, Informative

    would they not just survive reentry sans the missile shot and still pose a threat to those on the ground?

    Yes, they would. People on the ground will always be at some danger when you put an 11-ton satellite in low earth orbit.


    But it's easier to predict the impact point of a body that has a well known shape and orbit than that of a body that has been torn apart and pushed in random ways by an explosion.

  30. Re:Land Shuttle Atlantis through LEO debris? by Anonymous Coward · · Score: 2, Informative

    * Mightn't the energy required to break something this big into mostly harmless pieces also send some shrapnel into a higher orbit which could endanger shuttle launches and landings for quit a while?

    No. No matter how much energy you put into any of the pieces through this imapact, their resulting orbits will pass through the point of impact on subsequent orbits (discounting hyperbolic orbits, which won't happen, and wouldn't come back if it did). This point is so low (by definition) that these pieces will also be subject to the same significant drag that is bringing the satellite down. They will decay quickly.

    * Will Atlantis be safely on the ground before LEO is polluted with the debris of this experiment for an indeterminate period of time?

    Atlantis is scheduled to return on Feb 20th - well before this attempt would be made according to what I've heard. I work in this community, though not on this event - I'm absolutely sure they are taking this into consideration.

    * If it falls outside the U.S. are they going to send the antisat missile into someone else's airspace?
            * China, France, India, Pakistan, the shrapnel of the old U.S.S.R. all still have nuclear missile, mightn't antisats flying through/near their airspace make them a bit edgy?

    Ok, give them a little credit here. It's really not the first time we've launched missiles into space.

    * Didn't we sign some SALT or similar treaties against using weapons in space? If we decide to ignore this treaty, won't it be open season for satellites and space stations?

    There is no ASAT treaty. The closest thing to one is the 1972 ABM treaty - which Reagan basically gutted with SDI anyway.

    * If a piece of an uncontrolled satellite causes harm, we could say "sorry, it was an accident, nothing could be done." But if we intentionally break it up and a fragment causes harm, aren't we more liable?

    That whole area if international law is still wide open. But I'd prefer to have smaller bits coming down then larger ones personally.

  31. Re:Still dangerous without the shot? by compro01 · · Score: 2, Insightful

    then they can track it well enough to protect/recover the classified material. Assuming it comes down somewhere that they can get at. All the accurate tracking in the world won't help much if it comes down in Iran, North Korea, China, or any other country that would be interested in said material.
    --
    upon the advice of my lawyer, i have no sig at this time
  32. Re:Still dangerous without the shot? by multi+io · · Score: 2, Informative
    Yes, they would. People on the ground will always be at some danger when you put an 11-ton satellite in low earth orbit.

    You can minimize the danger if you inflict a sudden loss of momentum on the satellite such that it will come down in an unpopulated area, such as an ocean, with a high degree of predictability. If you can at the same time destroy the satellite's tank, which contains a highly poisonous substance, all the better. If you just let it come down on its own, it can come down anywhere (equator +/- the orbit's inclination), with the tank likely to be still intact.

    But it's easier to predict the impact point of a body that has a well known shape and orbit than that of a body that has been torn apart and pushed in random ways by an explosion.

    They're dealing with an out-of-control, non-aerodynamic object in orbit. Predicting the impact point of such a thing with an accuracy of less than a few thousand miles is impossible until the last one or two orbits (i.e. one our two hours before it comes down). Predicting it with an accuracy that would allow for any reasonably attempt at warning, let alone evacuating, people on the ground is well-nigh impossible.