Nuclear ICBM Targeting

[Irbis]

From old thread:

The Moscow ABM system was far from being marginal. It was (and remains) a very important component.

I've said this before but it bears repeating. The original UK plan in the 1950s was for the V-bomber fleet to attack 200 targets in the Eastern USSR. That was regarded as causing the USSR enough pain to make them think twice. However, by the early 1960s, the Soviet Air Defense system was perceived as having the ability to severely compromise the V-bomber fleet. So, the UK shifted to Polaris, one submarine on station with 16 missiles, each with three warheads. At most, that meant hitting 48 targets, meaning that 152 of the previously assigned targets were now uncovered. Thus, the Soviet Air Defense system had protected those 152 targets without ever firing a shot.

However, when anti-missile systems were installed, they made Polaris vulnerable. So, the British instituted a Polaris Upgrade called Chevaline. This removed one of the three warheads and replaced it with decoys and penetration aids (which didn't work but that's another story) plus targeted all 32 remaining warheads on Moscow in the assumption that one of them would get through (note the numbers there - an anticipated 97 percent kill rate for the ABM system in the presence of decoys etc they thought would work). The reality is that the British target list was now reduced to 1. The combined air defense and anti-missile screens had protected 199 out of the original 200 targets without firing a shot.

I searched, but didn't found an answer. I wonder, why bother and target Moscow at all then? 32 warheads to have one hit single city sounds worse than taking out 32 cities, even if none of them will be as important as Moscow? USSR could only field one ABM system, why bother attacking best defended spot when all you want is credible deterrence?

[Sea Skimmer]

Because the British figured that being a highly centralized state as it was, Moscow must be as important to the USSR as London was to the UK. How true that was is debatable. Also keep in mind the Moscow ABM system actually could defend a fairly large swath of the central USSR with its large interceptors, if the men manning the fire control center wanted, so scattering warheads over other central industrial cities would be futile. The exact footprint would depend on the direction the attacking missiles come from. That leaves attacking cities in Siberia and the edges of the USSR, which as far as deterrence goes, is not nearly so attractive.

Additionally, the Soviet's S-200 anti aircraft missiles were tested against IRBMs and successfully shot them down in trials, which the west knew about and complained about. The Polaris missile has ballistic performance towards the upper end of the IRBM range bracket so this meant at least on paper it might be shot down. S-200 might not always work in an ABM role, indeed the lack of a good search radar meant it was likely not to work well at all operationally, but the Soviets had a pretty large number of S-200 sites and this means firing single warheads at cities is even less attractive. S-200 was also thought to have a nuclear warhead, turns out most versions didn't, so it would only have had to get close to kill an RV.

[Sarevok]

Skimmer a lot of the more fanatical anti-ABM people claim that you needed a nuclear ABM to hit anything back then ? Their basic contention is that RVs are too fast and it is hitting them that is the problem. I thought the main problem was timely detection at sufficient range so the interceptors can catch them ?

[Sea Skimmer]

You need both. You need warning time for your slow scanning long range radars and computers to go from simply detecting a target to discriminate warheads from missile debris (this must be done even with no decoys ect...) and identifying targets, which doesn't happen all at once. Meanwhile the more warning time you have the lower performance and cheaper your interceptor missiles can be and still be effective. Warning time also gives more engagement chances, so you can fire a single interceptor at an incoming threat, wait to see if it kills, then shoot again if need be. This is opposed to firing multiple interceptors at a time to increase the overall kill chance at greater overall cost. This is important if you expect several thousand threat missiles and need to place interceptor missiles in expensive silos. You need silos not just for protection against enemy nukes and sabotage, but to contain the explosive hazard of such large and often nuclear armed missiles on bases. This is also why many Nike sites had underground magazines with elevators in the US, as they could be located close to houses ect...

Then you need precision enough to hit the target. If you used a nuclear warhead 'precision' really goes out the window, the neutron flux from a nuclear bomb going off in a near vacuum will poison the fissile material in nuclear warheads at considerable distances, this was also a reason to fire nuclear SAMs at bombers, and discrimination no longer needs to be much better then exploding the entire threat debris cloud. Indeed weapons like the 5 megaton bomb on Spartan stood a realistic chance of destroying not just multiple warheads from one missile, but perhaps even multiple warhead clusters. From a military standpoint the only objection to nuclear warheads for a while was cost; otherwise why wouldn't you want one? This logic finally failed when it was realized that nuclear warheads would ruin all our satellites, and satellites became more and more important for command and control. But by then it was already the 1980s and the US had been working on digital electronics for multiple generations of technology.

S-200 though was blowing up IRBMs with a conventional warhead, and its big 400+ pound warhead would have messed up anything it hit. IRBMs are much slower than the upper range of ICBMs though. ICBMs fly so fast they can outrun the blast and fragments of a conventional explosion to a non trivial degree, meaning that only an explosion in front is going to be highly effective. If your interceptor is already in front, you might as well go to the next step and just attempt to score a direct hit. This was the logic hit to kill came out of. A hit to kill warhead is much lighter, meaning either a higher performance missile, or a less costly missile, or both. Hit to kill demands high precision, which has its own costs, but most of those have ended up inflated by low production rates. Nike and HAWK made direct hits on relatively slow ballistic missiles back in the early 60s, but you just didn't want to rely on this alone back then. It really took several generations of digital technology to make it reasonable. Also pressure just rose for smaller, more mobile missiles for various reasons. Spartan was damn effective back in the late 60s, but also a 30,000lb missile. Today GBI weighs about the same, but has eight times the range.

You can also compromise as THAAD apparently does and have a hit to kill missile that releases a cluster of shrapnel right before it hits, but doesn't have any serious explosion. This slightly increases the footprint it covers. PAC-3 aims to hit to kill, but retains a full conventional warhead. But it was also expected to kill aircraft that aren't nice compact targets and highly agile.

[Irbis]

Because the British figured that being a highly centralized state as it was, Moscow must be as important to the USSR as London was to the UK. How true that was is debatable. Also keep in mind the Moscow ABM system actually could defend a fairly large swath of the central USSR with its large interceptors, if the men manning the fire control center wanted, so scattering warheads over other central industrial cities would be futile. The exact footprint would depend on the direction the attacking missiles come from. That leaves attacking cities in Siberia and the edges of the USSR, which as far as deterrence goes, is not nearly so attractive.

So, was it just because UK though Moscow to be the only important target in USSR?

I also wonder about what you stated - "Moscow ABM system actually could defend a fairly large swath of the central USSR". This might be true, but USSR was pretty big and central USSR was mostly devoid of good targets, meaning Moscow ABM would be used to defend Moscow only anyway, no? See list of 11 targets below - closest one is 750 km from Moscow, its ABM might have been good but I doubt it shielded that big area.

Additionally, the Soviet's S-200 anti aircraft missiles were tested against IRBMs and successfully shot them down in trials, which the west knew about and complained about. The Polaris missile has ballistic performance towards the upper end of the IRBM range bracket so this meant at least on paper it might be shot down. S-200 might not always work in an ABM role, indeed the lack of a good search radar meant it was likely not to work well at all operationally, but the Soviets had a pretty large number of S-200 sites and this means firing single warheads at cities is even less attractive. S-200 was also thought to have a nuclear warhead, turns out most versions didn't, so it would only have had to get close to kill an RV.

But, by logic, given 32 warheads, assuming 3 warheads per city, to eliminate malfunction and random hits from AA defense, you can target: Petersburg [4.9 mln], Kiev [2.8 mln], Baku [2 mln], Minsk [1.8 mln], Alma-Ata [1.4 mln], Novosibirsk [1.4 mln], Sverdlovsk [1.35 mln], Gorky [1.2 mln], Samara [1.15 mln], Kazan [1.15 mln], and Omsk [1.15 mln] - for combined total of 11 targets with 20.5 mln people, compared to 11.5 mln in Moscow. Wouldn't 10-20 warheads hitting population twice as large as one in Moscow be a better deterrent than 1-2 hitting Moscow and probably failing to destroy anything of big value seeing how hardened that city was? Or failing to do any damage at all in case ABM was underestimated? That, and seeing hitting population/industry center in city is the most effective form of dealing damage, and further hits produce rapidly dropping returns, dispersing warheads would make a lot more sense even had ABM didn't exist at all, no?

I just can't quite comprehend mindset that calls for a single dice roll when in case all you want is deterrence by population targeting. Single warhead hitting Moscow seems to be completely pointless seeing II World War produced nuclear-level damage in a lot of Soviet cities, especially Leningrad and Stalingrad, and didn't knocked USSR out of the war, so why assume it will do it now?

[Purple]

I just can't quite comprehend mindset that calls for a single dice roll when in case all you want is deterrence by population targeting. Single warhead hitting Moscow seems to be completely pointless seeing II World War produced nuclear-level damage in a lot of Soviet cities, especially Leningrad and Stalingrad, and didn't knocked USSR out of the war, so why assume it will do it now?

The mindset is simple. If you kill 99% of the Soviet population but not absolutely, undoubtedly, completely and irreparably level Moscow. Kremlin can still order the 1% sitting in hardened silos to fire off their missiles and level all of you. Let the Yankees kill the population all they want after the leadership is neutered. Would it have worked is another story altogether.

[Blayne]

Question why did the British so easily change their plans under the assumption they seem not at all be working with anyone else's nuclear forces like France's or the US's?

[Purple]

Question why did the British so easily change their plans under the assumption they seem not at all be working with anyone else's nuclear forces like France's or the US's?

They are not working with them. But they are working along side of them. They know that if WW3 kicks off everyone will be bombing Russia.

[atg]

From some reaing on the V bomber force it seems there were essentially two plans - a NATO one for if the US/NATO were going at it too, and one for the unlikely scenario of the UK facing the USSR by itself.

[JointStrikeFighter]

I just can't quite comprehend mindset that calls for a single dice roll when in case all you want is deterrence by population targeting. Single warhead hitting Moscow seems to be completely pointless seeing II World War produced nuclear-level damage in a lot of Soviet cities, especially Leningrad and Stalingrad, and didn't knocked USSR out of the war, so why assume it will do it now?

The mindset is simple. If you kill 99% of the Soviet population but not absolutely, undoubtedly, completely and irreparably level Moscow. Kremlin can still order the 1% sitting in hardened silos to fire off their missiles and level all of you. Let the Yankees kill the population all they want after the leadership is neutered. Would it have worked is another story altogether.

Given the russians had a dead hand system that could fire the missiles even after a decapitation strike it obviously would not have worked

[Sea Skimmer]

The Dead Hand system did not fire anything, it was a communication system to identify senior surviving officers who would then have to decide to fire or not. It was also not operational until the mid 1980s, well after decisions had been made on Chevaline, in fact after the decision was made to buy Trident, and after retirement of the last V force bombers.

Also I forgot to mention earlier that Chevaline also did harden the warheads, RVs and the warhead bus against the neutron flux of nuclear ABM missiles, but this could only work to a limited degree.

[Nephtys]

I was under the impression from US ICBM development, that the entire attempt to include heavier decoys and penaids were what first jumpstarted the use of MIRVs, when the mass of decent enough decoys approached another small warhead. The notion that they'd cut down the payload of Polaris by a third for decoys instead of the extra RV seems a bit strange.

[Simon_Jester]

Yeah, and my impression is that Chevaline was simply a bad idea- "a bit strange" describes it rather well, the product of political compromises and pressure and the desire for certainty in getting at least a few warheads through an increasingly tight missile defense system.

[Sea Skimmer]

They cut it down for decoys, and hardening everything. My bet is the decoys just used up extra weight, since a certain considerable minimal weight would be required for another hardened RV and warhead. It is a bit weird, as decoys cannot work even in theory against a terminal defense inside the atmosphere as they are too slow, but the logic pretty clearly was a third warhead won't gain us anything since the Soviets still get two ABM missiles per RV. 100 vs 48, so we've got to try something different.

MIRV began to be used by the US because the missiles guidance technology got advanced enough to make it work and the USAF got told it was not going to get over a thousand Minuteman, it had wanted 10,000. Minuteman III then introduced MIRV, but at the cost of greatly reduced yield, went from 1.2 megatons to three of 170kt. So saving decoy weight was not how this was done. All versions of Minuteman had some kind of penaid capability, but not all specific missiles carried the devices. Some fairly detailed declassified files now exist on this I noticed online, shep is now mirroring them on alternate wars, exist that cover this. It also talks some about hardening the missiles, as the earliest ones were highly vulnerable as nobody had really thought about the subject and the USAF wanted a cheap as possible missile.

http://www.alternatewars.com/WW3/WW3_Do ... uments.htm
USAF Ballistic Missile Program files on this page

[MKSheppard]

Skimmer a lot of the more fanatical anti-ABM people claim that you needed a nuclear ABM to hit anything back then ? Their basic contention is that RVs are too fast and it is hitting them that is the problem. I thought the main problem was timely detection at sufficient range so the interceptors can catch them ?

Nuclear ABM solves the problem of MIRVs, Decoys, and Jammers all so easily.

I've seen references to Spartan's warhead as possibly having a kill radius of 200 nautical miles against Minuteman RVs in the "base defense" mode for Minuteman fields.

Meanwhile, Polaris Chevaline deployed it's warheads, jammers, decoys etc in a 250~ mile long threat tube...

[Blayne]

I was having a discussion on mumble regarding my issues with the Tom Clancy novel "The Bear and the Dragon" where I stated my disbelief that in the time period of the book (~2000) the US would move a fleet within range of Guangdong and air raid the berths of the PLAN the PLA/N wouldn't fire off even a single long range anti ship missile. The people I was talking to said "well of course they wouldn't they were 'barely' in range and would be a waste of money." but somehow they won't fire a Sunburn but they would fire an ICBM, which is shot down by an AEGIS destroyer.

They also said this was also plausible, they said an AEGIS was able to shoot down a satellite; so my question is, is De facto ASAT capability equivilent to de facto ICBM capability?

[Sea Skimmer]

That book is godawful. The answer to the question is yes and no.

AEGIS shot down a satellite with an SM-3 missile design for ABM in 2008, the crap book has it use SM-2 missiles with slight modifications by one super genius guy. Its unlikely this would work, even with the firing ship sitting at the exact same location as the target (tiny effective defended area), because the performance of the SPY-1 radar is insufficient and SM-2 isn't that energetic in ABM terms. But its not impossible given a large salvo, which they did fire.

Given an interceptor with enough ceiling to physically make the hit, ASAT should be easier then ABM because the target is on such an absurdly predictable, already known trajectory, and is typically much larger then a nuclear warhead RV, even if its a bit faster. Incoming ballistic warheads also follow ballistic trajectories, but these change shape as the warhead is slowed down by the atmosphere which creates some problems, though it also strips away decoys. On the other hand ASAT requires such long range that you either need a massive radar to see the satellite a useful distance, or a computer capability to engage on remote data from another radar. Lake Erie, who shot down that satellite had a vastly upgraded radar over the normal SPY-1. Effective radar range of 1000km class rather then 400km or so stock. SPY-1 was never originally intended to be a really long range set. The cruiser also parked itself directly under the satellite flight path. SM-3 Block 1 missile performance isn't really good enough for ASAT operations without doing this in the first place. Later SM-3 blocks will be much better.

Now meanwhile, you want to hit an ICBM, SM-3 Block 1 should do the job if you parked right under the flight path, but if you want to defend an area bigger then one city that isn't going to work and you need a much bigger missile. So basically, a realistic, useful ASAT capability is easier then a realistic, useful anti ICBM capability, provided we are only considering low flying satellites like USA-193. Some satellites are 30,000 miles or further out into space and would present immensely difficult targets just because of how huge an interceptor missile you need.

Keep in mind also the US engaged satellites with air launched ASAT weapons back in the early 1960s. They didnt get direct hits, but that wasn't the point since the intention was to use nuclear warheads. This was before they realized how silly deadly EMP could make a nuke to satellites in space.

[MrDakka]

They didnt get direct hits, but that wasn't the point since the intention was to use nuclear warheads. This was before they realized how silly deadly EMP could make a nuke to satellites in space.

Nothing like a nuke to boost your probability of kill

[Sea Skimmer]

Keep in mind those early ASAT tests also had no homing systems, inertial only, so you basically had to use a nuke. Today we might make INS only work with a big conventional warhead, maybe. Later the Weapon System 437, which was a few modified Thor missiles e on a Pacific island deployed for the ASAT, also used INS only as far as I can tell, with and a nuke... a 1.44 megaton nuke. The short lived Nike Zeus ASAT deployment used a 20km nuke, but used the radio command guidance of Zeus.