4 ms·

>Hence, for one warhead, a defender can launch 4 interceptors and have a 96% chance of successfully intercepting the incoming warhead. >Unfortunately, those num

>Hence, for one warhead, a defender can launch 4 interceptors and have a 96% chance of successfully intercepting the incoming warhead. >Unfortunately, those numbers are optimistic. This part worth stressing, ceiling for more performant missiles, i.e. faster, terminal maneuvering, decoys are geometrically harder to intercept. Past mach ~10 terminal and functionally impossible because intercept kinematics will break interceptor airframes apart. AFAIK there hasn't been tests (i.e. FTM series) done on anything but staged/choreographed "icbm representative" targets. Iran arsenal charitably pretty shit, including high end. Hypothetical high end missile with 10%-20% single shot probability of kill requires 20-40 interceptors for 98% confidence, before decoys, i.e. 40x6=240 interceptors for 1 missile with 5 credible decoys. The math / economics breaks HARD with offensive missile improvements.

Voultapher 7mo ago
Lasers. No really, near-future laser systems with adaptive optics and good spotting - for example distributed SAR satellites - dramatically shift that balance [0]. [0] https://toughsf.blogspot.com/2025/05/the-laser-revolution-part-i-megawatt.html https://toughsf.blogspot.com/2025/05/the-laser-revolution-pa...
- gpderetta 7mo ago
  I doubt a MW laser can reliably intercept a reentry vehicle. A lot of energy is lost through the atmosphere when intercepting a warhead in space, from a land based laser. Once it reenters the atmosphere there might not be enough time. You also need to burn through the heatshield that the warhead is equipped with for reentry. Even if you can can deliver enough energy for long enough, there is no fuel to burn and it might not be easy to detonate or disable the warhead. For ICBMs, one idea was to use orbital, nuclear powered lasers to hit the missile on the boost phase. But that's very much not near-future. Lasers might still be useful for rockets, drones and cruise missiles of course.
  - O3marchnative 7mo ago
    > For ICBMs, one idea was to use orbital, nuclear powered lasers to hit the missile on the boost phase. Author here. Thank you for your insight. I took some time to read about the recently proposed "Golden Dome" defense system, and what you laid out seems to be the end goal [0]. It's difficult to tell how realistic this actually is. The size of the constellation of satellites needed seems prohibitive, to say the least. [0] https://armscontrolcenter.org/fact-sheet-golden-dome/ https://armscontrolcenter.org/fact-sheet-golden-dome/ [1] https://www.defenseone.com/ideas/2026/02/space-based-interceptors-make-even-less-sense-now/411153/ https://www.defenseone.com/ideas/2026/02/space-based-interce...
  - Voultapher 7mo ago
    I get the impression you didn't read the linked post. It goes into the details, atmospheric absorption for different wavelength, weather conditions, tracking time, interception time based on warhead hardness ratings and many more details. It's paper based, so in practice it will be more complicated and there are things it will have missed, and things we don't even know yet as being operational challenges for such systems. At the same time, it does present a compelling narrative and I'd much rather discuss individual assumptions or sources than dismiss it entirely based on a gut feeling.
- maxglute 7mo ago
  Maybe for subsonic, high end missiles I'm extremely skeptical. Need 5-10MW to get useful dwell power on high end hypersonic inherently shielded against reentry thermals. Speculative laser defense are infra size defense, not mobile trailer size. Factor in duty cycles (i.e. shots per minute) and it seems dead end. Half of economics of missile defense is mobility - building density relative to threats by moving platforms. Last 2 parts real constraints, high-end adversaries coordinate salvos to arrive in time. Interceptor magazine depth limited = still throw 100s of interceptors to engage multiple targets if required. Lasers = serial visual range engagement. Figure out dwell time + duty cycle to saturate. Hypersonic can go from over horizonal to hit target in 10 seconds, a laser couldn't engage more than 1-2 missiles in that time. Technically 1, because by the time you fried 1st target the 2nd is so close the shrapnel will hit on momentum.
- consumer451 7mo ago
  Lasers are not "all weather" weapons as far as I am aware. Clouds, snow, fog, rain, and just humidity all degrade their performance greatly.
  - O3marchnative 7mo ago
    The recently announced "Golden Dome" project intends to get around this issue by putting a vast constellation of satellites into orbit. Each satellite would likely need a serious source of power in order to use its laser. Assuming that's just an engineering problem, then the issue becomes coverage. That is, depending on the adversary's capabilities, you'd need an absolutely massive constellation in orbit [0]. [0] https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_system)#Architecture_and_doctrine https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_s...
    - consumer451 7mo ago
      This is such an insane plan, and I don't mean that in a good way. For one thing, it can do little to nothing about low flying nuclear tipped cruise missiles, especially in less than ideal weather. These already exist, so the Golden Dome system is already inadequate on day one.
    - gpderetta 7mo ago
      The idea has been around for a while: https://en.wikipedia.org/wiki/Brilliant_Pebbles https://en.wikipedia.org/wiki/Brilliant_Pebbles > https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_s https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_s... > President Donald Trump signed an executive order directing the United States Armed Forces to construct the [...] Golden Dome Well, that's just taking the piss!
  - Voultapher 7mo ago
    The linked article covers that in depth, it's not implausible to punch a hole through a storm with pulsed laser of that class. Honestly we don't know enough about these systems to know their operational limits but we know weather will play a role.
- apt-apt-apt-apt 7mo ago
  Try that on my spinning, mirror-coated missile!
dgroshev 7mo ago
That goes both ways. Terminal manoeuvring gets difficult as speeds increase, too. Besides, higher tier threats are intercepted outside the atmosphere, where it would be prohibitively expensive (in mass and accuracy) for RVs to manoeuvre. Your SSPK is way WAY too low. Also, the math on interceptions changes completely with multiple KKVs per interceptor (see NGI). Decoys don't work even at the highest end (ICBMs), see Chevaline's history and its rapid decomissioning for an example of just that.
- maxglute 7mo ago
  Terminal maneuvering vs interceptor kinematics difficult don't scale same at same rate with speed increase, a few Gs on reentry is magnified on interceptor end, the physics is not fair between attacker/defender. Higher threats are not exo atmosphere & midcourse that NGI targets, actual speculative high end threats (since we talking about speculative NGI capabilities) are hypersonic glide in upper atmosphere, which NGI can't target. It's even more extreme intercept problem, the intercept math for those class of threats is on paper even more lopsided against defender. NGI basically ensure US keeps pace with modern penetration aids proliferation, i.e NKR tier adversaries if they ever improve RVs + decoys from shit tier to mid tier. Chevaline was 50 years ago, not really relevant example, since issue was really economics of decoys vs just spamming mirv. Regardless, NGI trying to maintain 3/4/5 interceptor ratio instead of 30/40/50/100s against exo threats, which on spectrum is low/medium end. It does 0 against actual future highend threats of glide phase interception, an entirely different category.
  - dgroshev 7mo ago
    Again, the unfairness goes both ways: RVs need to carry substantial payloads, whereas KKVs only need DACS and sensing. THAAD KKVs weigh about 50kg; most effective payloads, even nuclear, would weigh substantially more. Hypersonic gliders can't be nearly as numerous as ballistic RVs because physics, and they are getting their own interceptor (GPI). I think this conversation would benefit from splitting theatre ballistic threats (evidently, those are now being effectively countered without 30 to 1 ratios) from strategic threats. For strategic threats, the logic is substantially more complex: even 50% intercept rate greatly complicates counter-force strikes and is valuable. In practice, the rate is substantially higher than 50%. Chevaline wasn't the only program, the US had its own they didn't end up deploying. Both countries concluded that effective decoys end up weighing roughly the same as warheads.

Voultapher 7mo ago

Lasers. No really, near-future laser systems with adaptive optics and good spotting - for example distributed SAR satellites - dramatically shift that balance [0]. [0] https://toughsf.blogspot.com/2025/05/the-laser-revolution-part-i-megawatt.html https://toughsf.blogspot.com/2025/05/the-laser-revolution-pa...

gpderetta 7mo ago
I doubt a MW laser can reliably intercept a reentry vehicle. A lot of energy is lost through the atmosphere when intercepting a warhead in space, from a land based laser. Once it reenters the atmosphere there might not be enough time. You also need to burn through the heatshield that the warhead is equipped with for reentry. Even if you can can deliver enough energy for long enough, there is no fuel to burn and it might not be easy to detonate or disable the warhead. For ICBMs, one idea was to use orbital, nuclear powered lasers to hit the missile on the boost phase. But that's very much not near-future. Lasers might still be useful for rockets, drones and cruise missiles of course.
- O3marchnative 7mo ago
  > For ICBMs, one idea was to use orbital, nuclear powered lasers to hit the missile on the boost phase. Author here. Thank you for your insight. I took some time to read about the recently proposed "Golden Dome" defense system, and what you laid out seems to be the end goal [0]. It's difficult to tell how realistic this actually is. The size of the constellation of satellites needed seems prohibitive, to say the least. [0] https://armscontrolcenter.org/fact-sheet-golden-dome/ https://armscontrolcenter.org/fact-sheet-golden-dome/ [1] https://www.defenseone.com/ideas/2026/02/space-based-interceptors-make-even-less-sense-now/411153/ https://www.defenseone.com/ideas/2026/02/space-based-interce...
- Voultapher 7mo ago
  I get the impression you didn't read the linked post. It goes into the details, atmospheric absorption for different wavelength, weather conditions, tracking time, interception time based on warhead hardness ratings and many more details. It's paper based, so in practice it will be more complicated and there are things it will have missed, and things we don't even know yet as being operational challenges for such systems. At the same time, it does present a compelling narrative and I'd much rather discuss individual assumptions or sources than dismiss it entirely based on a gut feeling.
maxglute 7mo ago
Maybe for subsonic, high end missiles I'm extremely skeptical. Need 5-10MW to get useful dwell power on high end hypersonic inherently shielded against reentry thermals. Speculative laser defense are infra size defense, not mobile trailer size. Factor in duty cycles (i.e. shots per minute) and it seems dead end. Half of economics of missile defense is mobility - building density relative to threats by moving platforms. Last 2 parts real constraints, high-end adversaries coordinate salvos to arrive in time. Interceptor magazine depth limited = still throw 100s of interceptors to engage multiple targets if required. Lasers = serial visual range engagement. Figure out dwell time + duty cycle to saturate. Hypersonic can go from over horizonal to hit target in 10 seconds, a laser couldn't engage more than 1-2 missiles in that time. Technically 1, because by the time you fried 1st target the 2nd is so close the shrapnel will hit on momentum.
consumer451 7mo ago
Lasers are not "all weather" weapons as far as I am aware. Clouds, snow, fog, rain, and just humidity all degrade their performance greatly.
- O3marchnative 7mo ago
  The recently announced "Golden Dome" project intends to get around this issue by putting a vast constellation of satellites into orbit. Each satellite would likely need a serious source of power in order to use its laser. Assuming that's just an engineering problem, then the issue becomes coverage. That is, depending on the adversary's capabilities, you'd need an absolutely massive constellation in orbit [0]. [0] https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_system)#Architecture_and_doctrine https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_s...
  - consumer451 7mo ago
    This is such an insane plan, and I don't mean that in a good way. For one thing, it can do little to nothing about low flying nuclear tipped cruise missiles, especially in less than ideal weather. These already exist, so the Golden Dome system is already inadequate on day one.
  - gpderetta 7mo ago
    The idea has been around for a while: https://en.wikipedia.org/wiki/Brilliant_Pebbles https://en.wikipedia.org/wiki/Brilliant_Pebbles > https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_s https://en.wikipedia.org/wiki/Golden_Dome_(missile_defense_s... > President Donald Trump signed an executive order directing the United States Armed Forces to construct the [...] Golden Dome Well, that's just taking the piss!
- Voultapher 7mo ago
  The linked article covers that in depth, it's not implausible to punch a hole through a storm with pulsed laser of that class. Honestly we don't know enough about these systems to know their operational limits but we know weather will play a role.
apt-apt-apt-apt 7mo ago
Try that on my spinning, mirror-coated missile!

dgroshev 7mo ago

That goes both ways. Terminal manoeuvring gets difficult as speeds increase, too. Besides, higher tier threats are intercepted outside the atmosphere, where it would be prohibitively expensive (in mass and accuracy) for RVs to manoeuvre. Your SSPK is way WAY too low. Also, the math on interceptions changes completely with multiple KKVs per interceptor (see NGI). Decoys don't work even at the highest end (ICBMs), see Chevaline's history and its rapid decomissioning for an example of just that.

maxglute 7mo ago
Terminal maneuvering vs interceptor kinematics difficult don't scale same at same rate with speed increase, a few Gs on reentry is magnified on interceptor end, the physics is not fair between attacker/defender. Higher threats are not exo atmosphere & midcourse that NGI targets, actual speculative high end threats (since we talking about speculative NGI capabilities) are hypersonic glide in upper atmosphere, which NGI can't target. It's even more extreme intercept problem, the intercept math for those class of threats is on paper even more lopsided against defender. NGI basically ensure US keeps pace with modern penetration aids proliferation, i.e NKR tier adversaries if they ever improve RVs + decoys from shit tier to mid tier. Chevaline was 50 years ago, not really relevant example, since issue was really economics of decoys vs just spamming mirv. Regardless, NGI trying to maintain 3/4/5 interceptor ratio instead of 30/40/50/100s against exo threats, which on spectrum is low/medium end. It does 0 against actual future highend threats of glide phase interception, an entirely different category.
- dgroshev 7mo ago
  Again, the unfairness goes both ways: RVs need to carry substantial payloads, whereas KKVs only need DACS and sensing. THAAD KKVs weigh about 50kg; most effective payloads, even nuclear, would weigh substantially more. Hypersonic gliders can't be nearly as numerous as ballistic RVs because physics, and they are getting their own interceptor (GPI). I think this conversation would benefit from splitting theatre ballistic threats (evidently, those are now being effectively countered without 30 to 1 ratios) from strategic threats. For strategic threats, the logic is substantially more complex: even 50% intercept rate greatly complicates counter-force strikes and is valuable. In practice, the rate is substantially higher than 50%. Chevaline wasn't the only program, the US had its own they didn't end up deploying. Both countries concluded that effective decoys end up weighing roughly the same as warheads.