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As far as I know ICBMs are still unstoppable once out of the boost phase and are moving at mach 20 by the time they leave the territory of the launching nation.

As far as I know ICBMs are still unstoppable once out of the boost phase and are moving at mach 20 by the time they leave the territory of the launching nation. The good news is that hypersonic missiles don't put us in any more danger than we're already in. The bad news is that despite being worthless we'll probably still spend a couple trillion dollars on them.

garmaine 7y ago
Actually no, there is lots of tech to stop ICBMs, in launch, orbital and re-entry phase. Hypersonic flight basically avoids all the weaknesses exploited by this older anti-ICBM tech.
- gruez 7y ago
  >Actually no, there is lots of tech to stop ICBMs, in launch, orbital and re-entry phase. what's the success rate on those? afaik they're irrelevant, at least to russia/us because you can evade them by simply launching enough missiles (you only need a few missiles to take out all major population centers).
  - garmaine 7y ago
    Classified. But the story of nuclear war is a bit more complicated than that. Sadly, city destruction doesn't usually fall into core considerations of win/loss.
    - oAlbe 7y ago
      > Sadly, city destruction doesn't usually fall into core considerations of win/loss. What does? Acts of occupation?
      - chipsa 7y ago
        Destroying their ability or willingness to make war. Doesn't need to be occupation, but if they can still fight, you haven't won yet. And destroying cities usually doesn't do much for stopping them from fighting. It mostly just makes them want to fight harder. The US lost the Vietnam War because we lost the willingness to fight. We can't effectively end the Afghanistan war because we can neither keep them from fighting, nor keep them from wanting to fight.
  - chipsa 7y ago
    The problem is launching enough missiles. Interceptors are expensive to develop, but cheap to make more of, and have relatively low cost of command and control (it doesn't matter if one gets launched by accident, right now). ICBMs are expensive to develop, expensive to make more of, and are expensive for command and control (because if one gets launched by accident, the world ends). So it's always going to be cheaper to make more interceptors than ICBMs. But beyond that, interceptors make the entire targeting situation more complex. If you've got 1000 warheads, and no defenses, you can hit 1000 targets (not actually true, because you have a certain amount of failure rate, but anyway). If you're facing 10 interceptors, and some of your targets must be destroyed, then you have to launch enough warheads at each target that must be destroyed to still go through even if all of them are intercepted. So now you have ~90 must destroy targets you can actually hit with your 1000 warheads, even though you're only facing 10 interceptors. Those 10 interceptors have effectively negated 900 enemy warheads.
    - gruez 7y ago
      >So it's always going to be cheaper to make more interceptors than ICBMs. What's the source for this? Because I've also heard the opposite. Also, given that interceptors have to travel faster and more accurate than warhead ICBMs, you'd think they're more expensive to develop and have a higher unit cost. >Those 10 interceptors have effectively negated 900 enemy warheads. * The calculation you presented only really makes sense for very high intercept success rates. If the intercept rate is (conservatively) 80%, if the enemy sends 10 missiles, and you use all 10 interceptors on each, there's still a 91% chance of at least one missile coming through (1-0.8^10). The odds get better if you have double the number of interceptors (34%), but it's still unacceptably high. You'd need overwhelmingly more interceptors. * I doubt there's 90 "must destroy" targets. If you spend all your interceptors protecting one target, even if that survives, your country is still utterly devastated that there's 0 hope of a counter attack. Does it really matter that washington, DC survived but the rest of the us is reduced to rubble?
      - garmaine 7y ago
        Nukes are expensive.
thunderbird120 7y ago
This is generally incorrect in several different ways. ICBMs are not invulnerable after their boost phase and ballistic missile defense continues to improve rapidly. The U.S. operates a small number of mid-course interceptors as part of the GMD system[1] to defend against small scale attacks from states such as North Korea. The low number of interceptors does not upset the balance of power with any larger nuclear states but that may change in the near future. The U.S. has been pursuing a new kill vehicle for its interceptors to replace the current EKV[2]. The MOKV was based on an earlier program to put multiple kill vehicles on a single rocket[3]. This would allow for a single rocket to potentially intercept up to 6 incoming warheads. What's more, this interceptor could be fitted to the SM-3 anti-ballistic missile missile used by the navy, massively increasing the total number of possible interceptors. Hypersonic missiles do not follow a predictable trajectory and fly much lower than ballistic missiles making their detection and engagement extremely difficult. Detection is actually the larger of the two issues. From the time a nuclear armed hypersonic missile is detected to the time it impacts could be fewer than 5 minutes. Far far less than the ~30 minutes of warning you get for ballistic missiles. This timeframe is too short for a proper chain of command and massively increases the risk of mistakes being made. It also incentivizes first strikes. Unfortunately, any nation that does not have this capability is at a massive disadvantage when confronted by a nation that does. Even if not used for nuclear strikes, hypersonics have the ability to destroy key, heavily defended targets with essentially no notice. This will likely make them extremely important for future engagements, especially naval ones. The U.S. has a large and very well defended navy which is key to its military strategy. China and Russia's focus on hypersonics is no coincidence. [1]https://en.wikipedia.org/wiki/Ground-Based_Midcourse_Defense https://en.wikipedia.org/wiki/Ground-Based_Midcourse_Defense [2]https://en.wikipedia.org/wiki/Exoatmospheric_Kill_Vehicle https://en.wikipedia.org/wiki/Exoatmospheric_Kill_Vehicle [3]https://en.wikipedia.org/wiki/Multiple_Kill_Vehicle https://en.wikipedia.org/wiki/Multiple_Kill_Vehicle

garmaine 7y ago

Actually no, there is lots of tech to stop ICBMs, in launch, orbital and re-entry phase. Hypersonic flight basically avoids all the weaknesses exploited by this older anti-ICBM tech.

gruez 7y ago
>Actually no, there is lots of tech to stop ICBMs, in launch, orbital and re-entry phase. what's the success rate on those? afaik they're irrelevant, at least to russia/us because you can evade them by simply launching enough missiles (you only need a few missiles to take out all major population centers).
- garmaine 7y ago
  Classified. But the story of nuclear war is a bit more complicated than that. Sadly, city destruction doesn't usually fall into core considerations of win/loss.
  - oAlbe 7y ago
    > Sadly, city destruction doesn't usually fall into core considerations of win/loss. What does? Acts of occupation?
    - chipsa 7y ago
      Destroying their ability or willingness to make war. Doesn't need to be occupation, but if they can still fight, you haven't won yet. And destroying cities usually doesn't do much for stopping them from fighting. It mostly just makes them want to fight harder. The US lost the Vietnam War because we lost the willingness to fight. We can't effectively end the Afghanistan war because we can neither keep them from fighting, nor keep them from wanting to fight.
- chipsa 7y ago
  The problem is launching enough missiles. Interceptors are expensive to develop, but cheap to make more of, and have relatively low cost of command and control (it doesn't matter if one gets launched by accident, right now). ICBMs are expensive to develop, expensive to make more of, and are expensive for command and control (because if one gets launched by accident, the world ends). So it's always going to be cheaper to make more interceptors than ICBMs. But beyond that, interceptors make the entire targeting situation more complex. If you've got 1000 warheads, and no defenses, you can hit 1000 targets (not actually true, because you have a certain amount of failure rate, but anyway). If you're facing 10 interceptors, and some of your targets must be destroyed, then you have to launch enough warheads at each target that must be destroyed to still go through even if all of them are intercepted. So now you have ~90 must destroy targets you can actually hit with your 1000 warheads, even though you're only facing 10 interceptors. Those 10 interceptors have effectively negated 900 enemy warheads.
  - gruez 7y ago
    >So it's always going to be cheaper to make more interceptors than ICBMs. What's the source for this? Because I've also heard the opposite. Also, given that interceptors have to travel faster and more accurate than warhead ICBMs, you'd think they're more expensive to develop and have a higher unit cost. >Those 10 interceptors have effectively negated 900 enemy warheads. * The calculation you presented only really makes sense for very high intercept success rates. If the intercept rate is (conservatively) 80%, if the enemy sends 10 missiles, and you use all 10 interceptors on each, there's still a 91% chance of at least one missile coming through (1-0.8^10). The odds get better if you have double the number of interceptors (34%), but it's still unacceptably high. You'd need overwhelmingly more interceptors. * I doubt there's 90 "must destroy" targets. If you spend all your interceptors protecting one target, even if that survives, your country is still utterly devastated that there's 0 hope of a counter attack. Does it really matter that washington, DC survived but the rest of the us is reduced to rubble?
    - garmaine 7y ago
      Nukes are expensive.

thunderbird120 7y ago

This is generally incorrect in several different ways. ICBMs are not invulnerable after their boost phase and ballistic missile defense continues to improve rapidly. The U.S. operates a small number of mid-course interceptors as part of the GMD system[1] to defend against small scale attacks from states such as North Korea. The low number of interceptors does not upset the balance of power with any larger nuclear states but that may change in the near future. The U.S. has been pursuing a new kill vehicle for its interceptors to replace the current EKV[2]. The MOKV was based on an earlier program to put multiple kill vehicles on a single rocket[3]. This would allow for a single rocket to potentially intercept up to 6 incoming warheads. What's more, this interceptor could be fitted to the SM-3 anti-ballistic missile missile used by the navy, massively increasing the total number of possible interceptors. Hypersonic missiles do not follow a predictable trajectory and fly much lower than ballistic missiles making their detection and engagement extremely difficult. Detection is actually the larger of the two issues. From the time a nuclear armed hypersonic missile is detected to the time it impacts could be fewer than 5 minutes. Far far less than the ~30 minutes of warning you get for ballistic missiles. This timeframe is too short for a proper chain of command and massively increases the risk of mistakes being made. It also incentivizes first strikes. Unfortunately, any nation that does not have this capability is at a massive disadvantage when confronted by a nation that does. Even if not used for nuclear strikes, hypersonics have the ability to destroy key, heavily defended targets with essentially no notice. This will likely make them extremely important for future engagements, especially naval ones. The U.S. has a large and very well defended navy which is key to its military strategy. China and Russia's focus on hypersonics is no coincidence. [1]https://en.wikipedia.org/wiki/Ground-Based_Midcourse_Defense https://en.wikipedia.org/wiki/Ground-Based_Midcourse_Defense [2]https://en.wikipedia.org/wiki/Exoatmospheric_Kill_Vehicle https://en.wikipedia.org/wiki/Exoatmospheric_Kill_Vehicle [3]https://en.wikipedia.org/wiki/Multiple_Kill_Vehicle https://en.wikipedia.org/wiki/Multiple_Kill_Vehicle