7 ms·

More specifically, nuclear arms, where the budget is "there is no budget." Just the inertial guidance system of a 90's-era ICBM cost over six figures per missil

More specifically, nuclear arms, where the budget is "there is no budget." Just the inertial guidance system of a 90's-era ICBM cost over six figures per missile. The ability to precisely place a missile without any external navigation (except for stars.) Once it gets cheap enough, it'll probably go into cruise missiles; it could eliminate or reduce the need for terrain contour matching, which requires radar transmission. I'm not 100% certain but I believe when MEMS accelerometers first came out, the better ones were subject to arms controls because of fears they could be used in missiles.

littlestymaar 2y ago
Nuclear arms doesn't need as much accuracy as other weapons though: when using a cruise missile or a glide bomb with a few hundreds of kilograms of explosives, you need metric precision to get the military effect, when the payload is a 100kt bomb, then 100m is accurate enough. Unlike other bombs it must absolutely be 100% resilient to any kind of spoofing though, for obvious reasons, hence GNSS is a nonstarter for those when they are the default guidance system for other weapons (with backups, for cruise missile).
- dingaling 2y ago
  > when the payload is a 100kt bomb, then 100m is accurate enough Not accurate enough for counterforce. When a missile silo lid can withstand 600 atmospheres of overpressure, "close enough" isn't good enough.
- KennyBlanken 2y ago
  My point was that nuclear missile development gets a blank check and I cited the over-six-figure intertial guidance units in 80's and 90's era missiles as an example of this. I'm not sure what point you're trying to make here? Accuracy is incredibly important because you don't put a nuke somewhere to kill people; you put it there to destroy infrastructure. More specifically nuclear missile silos, and bomb shelters (well, the people inside them.) Reducing the CEP means you can use a smaller nuclear yield to get the job done, which is preferable for a number of reasons, including politics, but also allowing for more targets in a strike. The very latest US ICBMs are suspected of having sub-100m CEP. CEP for ICBMs is "bad" enough that it is typical for planners to figure three warheads per target, but accuracy is rumored to be getting good enough where that is no longer necessary.
  - dgroshev 2y ago
    > you don't put a nuke somewhere to kill people; you put it there to destroy infrastructure. More specifically nuclear missile silos, and bomb shelters (well, the people inside them.) It depends. "Counter-force" strikes aim to destroy the ability to respond or attack with nuclear weapons, not infrastructure per se. So that's just silos, warhead storage sites, submarines in port, airfields, etc. The US is doctrinally counter-force for about half a century. This doctrine is also reflected in technological choices: lower yields and higher precision mean lower fallout, collateral damage, and fratricide when hunting for silos, but aren't that useful for city busting. "Counter-value" strikes are pure destruction of cities and killing of people. Russia seems to have this doctrine [1]. This is a very inflexible doctrine, because you can't credibly threaten to execute a counter-value attack on the US over things that don't seem to be worth a response in kind (like a defeat in Ukraine). It's much cheaper though. > The very latest US ICBMs are suspected of having sub-100m CEP Apparently the precision is good enough for photos like the one on page 23 here https://www.osti.gov/servlets/purl/1557069 https://www.osti.gov/servlets/purl/1557069 [1]: At least strategically. There is a hybrid strategy of targeting military-related infrastructure, which Russia seems to have adopted for less-than-strategic forces according to recent leaks https://www.ft.com/content/237e1e55-401d-4eeb-875b-03fe68f81575 https://www.ft.com/content/237e1e55-401d-4eeb-875b-03fe68f81... .
- roywiggins 2y ago
  It makes a difference for hard targets, see the new nuclear "super-fuzes." It can take several warheads to destroy a missile silo with high probability, because even landing a little off-target can spare the silo. Greater precision means it takes substantially fewer. https://thebulletin.org/2017/03/how-us-nuclear-force-modernization-is-undermining-strategic-stability-the-burst-height-compensating-super-fuze/ https://thebulletin.org/2017/03/how-us-nuclear-force-moderni...
  - littlestymaar 2y ago
    I don't really get this argument: if you have a metric precision munition in an ICBM then even an inert warhead is going to be enough to penetrate and destroy due to the kinetic energy coming from the hypersonic nature of the reentry vehicle (and even if kinetic energy itself wasn't sufficient, a conventional payload would be) Nuclear bombs are useful because you don't need precision to get the effectiveness, but if you have the precision then why would you bother with the consequences of using nukes…
    - roywiggins 2y ago
      Not if the silo can withstand a direct hit from anything short of a nuclear bomb going off nearby. ICBMs aren't that precise- or they didn't used to be- and that's why you'd compensate for that with nuclear warheads. Or, alternatively, early ICBMs would have seemed nearly pointless to develop before nuclear weapons existed to put on them. If a superfuze or a super-IMU means that you can kill one silo with one nuke, that is a huge improvement over the old status quo, where it was assumed to take several, simply because the CEP was larger than the radius at which they can destroy a silo. If someone does have an conventional ICBM that can reliably take out nuclear silos that would be an even bigger deal. Of course the US military has been working on conventionally-armed ICBMs: https://en.m.wikipedia.org/wiki/Conventional_Prompt_Strike https://en.m.wikipedia.org/wiki/Conventional_Prompt_Strike
      - littlestymaar 2y ago
        > Not if the silo can withstand a direct hit from anything short of a nuclear bomb going off nearby But this kind of silos simply doesn't exist. Yes you could theoretically imagine such a silo, but because the threat of a conventional bunker buster payload hasn't been very realistic when it comes to nuclear silos, they aren't designed to deal with such a thread and instead focus on protection against the kind of overpressure that is caused by an nuclear explosion occurring around.
- rcxdude 2y ago
  They do need very good IMUs though, because of their range and flight time: uncertainty in position increases with both of those.
jfengel 2y ago
In Russia's case, there does appear to be "no budget". The weapons were intended as a last resort, and so they are a great target for diverting maintenance funds. It's not quite so bad as "we are certain that they will not successfully launch any nukes" and so they're still being treated with caution. But the US keeps upping what it allows Ukraine to do as it loses its fear of World War III. As it applies to the US... yeah, the sky is the limit for military spending.
- dgroshev 2y ago
  There is no fear of WWIII, that's part media invention, part political excuse, part useful idiots. A "World War" requires an opponent worthy of a world-wide conflict, and Russia is anything but, being stuck in Ukraine for three years and losing most of its army in the process. Conventionally, Russia is no match for NATO, with enough political will it'd be a Desert Storm-like curb stomp. The only way it's not is the US abandoning NATO, then it can be quite painful, but even then Russian economy is no match for the EU. As for nuclear weapons, they are practically useless. Anything but strategic use would have little impact on the battlefield, but will immediately alienate China and India. They have their own border conflicts and do NOT want the nuclear taboo to be broken, and they are holding the leash, being the only economic and technological lifeline Russia has. A strike against the US would be suicidal for obvious reasons. Also, notice how Putin and his officials talk about nuclear use a lot, but there is still zero evidence of any action (such as dispersal of road-based ICBMs or 12th GUMO taking warheads out of storage). Rhetoric is cheap and not credible. The only real fear of escalation here is "horizontal" escalation: Russia stirring shit elsewhere. Advanced anti-ship missiles to Houthis, handing nuclear technology to North Koreans or submarine technology to China, that kind of thing. But that's already seem to be happening, and there isn't much more that Russia can do.
  - JumpCrisscross 2y ago
    > will immediately alienate China and India To drive this home, India and China have a moderately high probability of engaging in armed conflict with a nuclear power in the next decades. (India with Pakistan and China, China with America.) They do not want tactical nukes to be normalised in prelude to those conflicts.
rcxdude 2y ago
High-grade accelerometers (of any kind) are still subject to export restrictions, especially ones which can handle the G-forces in missiles.

littlestymaar 2y ago

Nuclear arms doesn't need as much accuracy as other weapons though: when using a cruise missile or a glide bomb with a few hundreds of kilograms of explosives, you need metric precision to get the military effect, when the payload is a 100kt bomb, then 100m is accurate enough. Unlike other bombs it must absolutely be 100% resilient to any kind of spoofing though, for obvious reasons, hence GNSS is a nonstarter for those when they are the default guidance system for other weapons (with backups, for cruise missile).

dingaling 2y ago
> when the payload is a 100kt bomb, then 100m is accurate enough Not accurate enough for counterforce. When a missile silo lid can withstand 600 atmospheres of overpressure, "close enough" isn't good enough.
KennyBlanken 2y ago
My point was that nuclear missile development gets a blank check and I cited the over-six-figure intertial guidance units in 80's and 90's era missiles as an example of this. I'm not sure what point you're trying to make here? Accuracy is incredibly important because you don't put a nuke somewhere to kill people; you put it there to destroy infrastructure. More specifically nuclear missile silos, and bomb shelters (well, the people inside them.) Reducing the CEP means you can use a smaller nuclear yield to get the job done, which is preferable for a number of reasons, including politics, but also allowing for more targets in a strike. The very latest US ICBMs are suspected of having sub-100m CEP. CEP for ICBMs is "bad" enough that it is typical for planners to figure three warheads per target, but accuracy is rumored to be getting good enough where that is no longer necessary.
- dgroshev 2y ago
  > you don't put a nuke somewhere to kill people; you put it there to destroy infrastructure. More specifically nuclear missile silos, and bomb shelters (well, the people inside them.) It depends. "Counter-force" strikes aim to destroy the ability to respond or attack with nuclear weapons, not infrastructure per se. So that's just silos, warhead storage sites, submarines in port, airfields, etc. The US is doctrinally counter-force for about half a century. This doctrine is also reflected in technological choices: lower yields and higher precision mean lower fallout, collateral damage, and fratricide when hunting for silos, but aren't that useful for city busting. "Counter-value" strikes are pure destruction of cities and killing of people. Russia seems to have this doctrine [1]. This is a very inflexible doctrine, because you can't credibly threaten to execute a counter-value attack on the US over things that don't seem to be worth a response in kind (like a defeat in Ukraine). It's much cheaper though. > The very latest US ICBMs are suspected of having sub-100m CEP Apparently the precision is good enough for photos like the one on page 23 here https://www.osti.gov/servlets/purl/1557069 https://www.osti.gov/servlets/purl/1557069 [1]: At least strategically. There is a hybrid strategy of targeting military-related infrastructure, which Russia seems to have adopted for less-than-strategic forces according to recent leaks https://www.ft.com/content/237e1e55-401d-4eeb-875b-03fe68f81575 https://www.ft.com/content/237e1e55-401d-4eeb-875b-03fe68f81... .
roywiggins 2y ago
It makes a difference for hard targets, see the new nuclear "super-fuzes." It can take several warheads to destroy a missile silo with high probability, because even landing a little off-target can spare the silo. Greater precision means it takes substantially fewer. https://thebulletin.org/2017/03/how-us-nuclear-force-modernization-is-undermining-strategic-stability-the-burst-height-compensating-super-fuze/ https://thebulletin.org/2017/03/how-us-nuclear-force-moderni...
- littlestymaar 2y ago
  I don't really get this argument: if you have a metric precision munition in an ICBM then even an inert warhead is going to be enough to penetrate and destroy due to the kinetic energy coming from the hypersonic nature of the reentry vehicle (and even if kinetic energy itself wasn't sufficient, a conventional payload would be) Nuclear bombs are useful because you don't need precision to get the effectiveness, but if you have the precision then why would you bother with the consequences of using nukes…
  - roywiggins 2y ago
    Not if the silo can withstand a direct hit from anything short of a nuclear bomb going off nearby. ICBMs aren't that precise- or they didn't used to be- and that's why you'd compensate for that with nuclear warheads. Or, alternatively, early ICBMs would have seemed nearly pointless to develop before nuclear weapons existed to put on them. If a superfuze or a super-IMU means that you can kill one silo with one nuke, that is a huge improvement over the old status quo, where it was assumed to take several, simply because the CEP was larger than the radius at which they can destroy a silo. If someone does have an conventional ICBM that can reliably take out nuclear silos that would be an even bigger deal. Of course the US military has been working on conventionally-armed ICBMs: https://en.m.wikipedia.org/wiki/Conventional_Prompt_Strike https://en.m.wikipedia.org/wiki/Conventional_Prompt_Strike
    - littlestymaar 2y ago
      > Not if the silo can withstand a direct hit from anything short of a nuclear bomb going off nearby But this kind of silos simply doesn't exist. Yes you could theoretically imagine such a silo, but because the threat of a conventional bunker buster payload hasn't been very realistic when it comes to nuclear silos, they aren't designed to deal with such a thread and instead focus on protection against the kind of overpressure that is caused by an nuclear explosion occurring around.
rcxdude 2y ago
They do need very good IMUs though, because of their range and flight time: uncertainty in position increases with both of those.

jfengel 2y ago

In Russia's case, there does appear to be "no budget". The weapons were intended as a last resort, and so they are a great target for diverting maintenance funds. It's not quite so bad as "we are certain that they will not successfully launch any nukes" and so they're still being treated with caution. But the US keeps upping what it allows Ukraine to do as it loses its fear of World War III. As it applies to the US... yeah, the sky is the limit for military spending.

dgroshev 2y ago
There is no fear of WWIII, that's part media invention, part political excuse, part useful idiots. A "World War" requires an opponent worthy of a world-wide conflict, and Russia is anything but, being stuck in Ukraine for three years and losing most of its army in the process. Conventionally, Russia is no match for NATO, with enough political will it'd be a Desert Storm-like curb stomp. The only way it's not is the US abandoning NATO, then it can be quite painful, but even then Russian economy is no match for the EU. As for nuclear weapons, they are practically useless. Anything but strategic use would have little impact on the battlefield, but will immediately alienate China and India. They have their own border conflicts and do NOT want the nuclear taboo to be broken, and they are holding the leash, being the only economic and technological lifeline Russia has. A strike against the US would be suicidal for obvious reasons. Also, notice how Putin and his officials talk about nuclear use a lot, but there is still zero evidence of any action (such as dispersal of road-based ICBMs or 12th GUMO taking warheads out of storage). Rhetoric is cheap and not credible. The only real fear of escalation here is "horizontal" escalation: Russia stirring shit elsewhere. Advanced anti-ship missiles to Houthis, handing nuclear technology to North Koreans or submarine technology to China, that kind of thing. But that's already seem to be happening, and there isn't much more that Russia can do.
- JumpCrisscross 2y ago
  > will immediately alienate China and India To drive this home, India and China have a moderately high probability of engaging in armed conflict with a nuclear power in the next decades. (India with Pakistan and China, China with America.) They do not want tactical nukes to be normalised in prelude to those conflicts.

rcxdude 2y ago

High-grade accelerometers (of any kind) are still subject to export restrictions, especially ones which can handle the G-forces in missiles.