3 ms·

That goes both ways. Terminal manoeuvring gets difficult as speeds increase, too. Besides, higher tier threats are intercepted outside the atmosphere, where it

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.
  - maxglute 7mo ago
    The unfairness goes both ways, but one way MUCH harder. On terminal interception, RV weight less critical factor - the unfairness is RV kinematic requirements simply lower than KKV kinematic requirements, and ceiling where KKVs physically cannot intercept regardless of weight / sensor / motor quality is below theoretic ceiling for RV, and closer offense moves towards that ceiling (+speed, +maneuver even minor jiggles) the worse KKV approach (and economics) breaks down. Weight might be proxy for cost, i.e. salvo + interception math. Which is fair, but then we don't know NGI cost and we don't know if adversaries can simply build more missiles at lower cost to extend exchange ratio gap anyway. On midcourse vs hypersonic, GPI like DEW vs high-end missiles is hypothetical/speculative interception stack, i.e. low technology readiness level, given actual harder interception physics / maneuver gap for non vacuum vs vacuum midcourse, there's no indication it will ever "work", i.e. stuck in TRL <4 "theory" wall, at least on relevant timelines. >In practice, the rate is substantially higher than 50%. For exo atmosphere midcourse, in practice we don't have any solid data (more accurately in on paper none actually exist) on midcourse interception rates vs highend, i.e. tier1 missiles + penaids. Only data we have is highly scripted/goldilocks FTM44 without penaids on maximum convenient interception conditions/geometry. Since SPKK doesn't scale linearly vs missile or penaid performance, SPKK of single digit approaching 0 is not out of question for missiles with complex penaids or improved kinematics. > decoys end up weighing roughly the same as warheads. Due to tech limitations 30-50 years ago. Modern missiles have massively reduced size of penaids vs payload, i.e. Iskander miniaturized (6) EW/active spoofing penaids is like ~5% of the warhead weight. High end ICBMs speculated to have 30-50. Chevaline/early decoys were bruteforce mass/physics mimicry methods, and tier1 powers like like UK/US figured better off stuffing actual warheads for strategic/nuclear under those conditions. VS less capable adversaries who may have to go warhead + penaid route due to limitations, i.e. lower end adversaries only ground/TEL leg and limited nuclear warheads #s, who'd much better off spreading limited warheads over many missiles with penaids then hedge on MIRV stuffing. >splitting ... strategic threats I think more useful to split strategic threats by levels, NGI is designed to stay at pace or ahead of mid/low end adversaries modernizing ballistic threats... which granted is basically everyone except PRC and maybe RU. VS high end adversaries, if we look at the speculative roadmap of hypersonic glide vs glide phase interceptor and high end penaids, in terms of technology readiness and implementation, the gap could very well be increasing, i.e. PLARF with mass hypersonic glides 5-10 years from now has much higher chance of overmatching GPI progress. AFAIK, there isn't even a PROPOSED midcourse interception solution(golden dome mostly tracking) vs powered glide (i.e. scramjets) with sustained maneuverability. The TLDR is short/medium term forecasted missile defense (i.e. GPI is 2035s) is not even in the same room as deployed/fielded highend missile offense (assuming they work) and not in the same building as forecasted (highend) short/medium term missile offense.

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.
- maxglute 7mo ago
  The unfairness goes both ways, but one way MUCH harder. On terminal interception, RV weight less critical factor - the unfairness is RV kinematic requirements simply lower than KKV kinematic requirements, and ceiling where KKVs physically cannot intercept regardless of weight / sensor / motor quality is below theoretic ceiling for RV, and closer offense moves towards that ceiling (+speed, +maneuver even minor jiggles) the worse KKV approach (and economics) breaks down. Weight might be proxy for cost, i.e. salvo + interception math. Which is fair, but then we don't know NGI cost and we don't know if adversaries can simply build more missiles at lower cost to extend exchange ratio gap anyway. On midcourse vs hypersonic, GPI like DEW vs high-end missiles is hypothetical/speculative interception stack, i.e. low technology readiness level, given actual harder interception physics / maneuver gap for non vacuum vs vacuum midcourse, there's no indication it will ever "work", i.e. stuck in TRL <4 "theory" wall, at least on relevant timelines. >In practice, the rate is substantially higher than 50%. For exo atmosphere midcourse, in practice we don't have any solid data (more accurately in on paper none actually exist) on midcourse interception rates vs highend, i.e. tier1 missiles + penaids. Only data we have is highly scripted/goldilocks FTM44 without penaids on maximum convenient interception conditions/geometry. Since SPKK doesn't scale linearly vs missile or penaid performance, SPKK of single digit approaching 0 is not out of question for missiles with complex penaids or improved kinematics. > decoys end up weighing roughly the same as warheads. Due to tech limitations 30-50 years ago. Modern missiles have massively reduced size of penaids vs payload, i.e. Iskander miniaturized (6) EW/active spoofing penaids is like ~5% of the warhead weight. High end ICBMs speculated to have 30-50. Chevaline/early decoys were bruteforce mass/physics mimicry methods, and tier1 powers like like UK/US figured better off stuffing actual warheads for strategic/nuclear under those conditions. VS less capable adversaries who may have to go warhead + penaid route due to limitations, i.e. lower end adversaries only ground/TEL leg and limited nuclear warheads #s, who'd much better off spreading limited warheads over many missiles with penaids then hedge on MIRV stuffing. >splitting ... strategic threats I think more useful to split strategic threats by levels, NGI is designed to stay at pace or ahead of mid/low end adversaries modernizing ballistic threats... which granted is basically everyone except PRC and maybe RU. VS high end adversaries, if we look at the speculative roadmap of hypersonic glide vs glide phase interceptor and high end penaids, in terms of technology readiness and implementation, the gap could very well be increasing, i.e. PLARF with mass hypersonic glides 5-10 years from now has much higher chance of overmatching GPI progress. AFAIK, there isn't even a PROPOSED midcourse interception solution(golden dome mostly tracking) vs powered glide (i.e. scramjets) with sustained maneuverability. The TLDR is short/medium term forecasted missile defense (i.e. GPI is 2035s) is not even in the same room as deployed/fielded highend missile offense (assuming they work) and not in the same building as forecasted (highend) short/medium term missile offense.