PLA Anti-Air Missile (SAM) systems

AndrewS said:

Compare what we know of the SM-6 and the dedicated YJ-21 ASBM launched from the Type-055. The caveat is that the YJ-21 is likely a significantly larger missile.

The YJ-21 has a range of 1500? Km and a terminal speed of Mach 10?
In ASBM mode, the SM-6 has a range of 500? km and a maximum speed of Mach 3.5

A missile travelling at Mach 3.5 is a lot easier to hit than one at Mach 10.
With these numbers, there is a 8x difference in kinetic energy for the same mass.

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The YJ-21's warhead is much smaller and thinner than you think when it's diving.
Also the huge speed gap between the manoeuverering YJ-21 warhead and the climbing SM-6 gives a very tiny intercept window for the SM-6. In real world SM-6 will mostly miss the target.
BTW a lot of Chinese sources indicated that they normally use over 20 ASBMs, ship/air launched or the land based together in a coordinated attack, against one aircraft carrier.

A larger warhead should in theory provide superior performance against Iskander-like modern tactical ballistic systems. Which have proven difficult targets for other AD systems.

I don't think China designed the HQ-9 that way by chance. In 2023, China was the world's 2nd largest ballistic missile shooter, only behind Russia, which is in war. They should have a very clear idea on what features are optimal for AD, if they say 150kg warhead is needed for the modern battlefield, they should be right about that.

Index said:

A larger warhead should in theory provide superior performance against Iskander-like modern tactical ballistic systems. Which have proven difficult targets for other AD systems.

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Superior compared to a smaller warhead, sure, but it should still be inferior to hit-to-kill systems for use against BM targets, even more so if the BM has submunitions. Hit-to-kill has its own disadvantages of course against other types of targets.

Index said:

I don't think China designed the HQ-9 that way by chance. In 2023, China was the world's 2nd largest ballistic missile shooter, only behind Russia, which is in war. They should have a very clear idea on what features are optimal for AD, if they say 150kg warhead is needed for the modern battlefield, they should be right about that.

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Isn't the rumor that one of the main changes for the HQ-9B a lighter warhead, along with a composite case? I don't think retaining a heavier warhead is that important for the PLA.

totenchan said:

Superior compared to a smaller warhead, sure, but it should still be inferior to hit-to-kill systems for use against BM targets, even more so if the BM has submunitions. Hit-to-kill has its own disadvantages of course against other types of targets.

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No? The problem of hit-to-kill and small warhead systems is that most of the time, they can't hit more advanced ballistic missiles at all.

A larger warhead makes the envelope for a successful interception larger. It's bad when you're fighting cheap garbage targets, but invaluable when you absolutely need to shoot down the enemy at any cost.

Index said:

No? The problem of hit-to-kill and small warhead systems is that most of the time, they can't hit more advanced ballistic missiles at all.

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What? If you want ABM capability in any reasonable form factor, with a large area defended, hit-to-kill is really the best choice. Being lighter allows for better kinematics, and a smaller missile.

Index said:

A larger warhead makes the envelope for a successful interception larger. It's bad when you're fighting cheap garbage targets, but invaluable when you absolutely need to shoot down the enemy at any cost.

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A larger warhead, or a more maneuverable kill vehicle, can both make the envelope for a successful interception larger. A larger warhead won't be as efficient as HTK against ballistic targets, especially if the target in question has submunitions.

totenchan said:

What? If you want ABM capability in any reasonable form factor, with a large area defended, hit-to-kill is really the best choice. Being lighter allows for better kinematics, and a smaller missile.

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It doesn't seem to be what China thinks. Afaik hit to kill missiles have only been employed on small AAMs meant against cheap targets by China.

totenchan said:

A larger warhead, or a more maneuverable kill vehicle, can both make the envelope for a successful interception larger. A larger warhead won't be as efficient as HTK against ballistic targets, especially if the target in question has submunitions.

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You can also make kinematics better by making the missile bigger, like the HQ-9 is.

We'll probably not find out if it works as intended unless China publishes exercise data or HQ-9 are used in high intensity conflicts. But given that China does so much air defense/ballistic missile testing, it seems to indicate there is a reason for how items like HQ-9 are designed. Plus they've had very competent performance in public trials before.

Index said:

It doesn't seem to be what China thinks. Afaik hit to kill missiles have only been employed on small AAMs meant against cheap targets by China.

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We have no real insight into what China thinks. However its been in the public record that there's been at least one HTK ABM missile in development in China for like a decade now.

Index said:

You can also make kinematics better by making the missile bigger, like the HQ-9 is.

We'll probably not find out if it works as intended unless China publishes exercise data or HQ-9 are used in high intensity conflicts. But given that China does so much air defense/ballistic missile testing, it seems to indicate there is a reason for how items like HQ-9 are designed. Plus they've had very competent performance in public trials before.

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I highly doubt the current HQ-9 missile is going to be China's dedicated ABM missile, even if it does have that capability. A missile that's mainly meant to intercept aerodynamic targets simply isn't going to be as good at ABM as something that is specially developed for that role. Which is why we see rumors about things like the HQ-19 and HQ-29.

totenchan said:

We have no real insight into what China thinks. However its been in the public record that there's been at least one HTK ABM missile in development in China for like a decade now.

I highly doubt the current HQ-9 missile is going to be China's dedicated ABM missile, even if it does have that capability. A missile that's mainly meant to intercept aerodynamic targets simply isn't going to be as good at ABM as something that is specially developed for that role. Which is why we see rumors about things like the HQ-19 and HQ-29.

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Hq-19 is an exoatmospheric interceptor. IIRC it runs off the same basic battery structure as Hq-9, while the Hq-9 basic missile is able to intercept at terminal approach similar to S400. It's different roles.

I haven't seen any sources saying what Hq-19 uses though, logically it should be similar to Hq-9, but there are no sources saying it's not hit to kill either.

HQ-19 is probably terminal BMD with some exo capability, like THAAD. There is a larger system (DN-3), which sometimes gets confused with the aforementioned, for proper midcourse interceptions using an EKV.
Both are very likely to be using HTK technology.

gpt said:

HQ-19 is probably terminal BMD with some exo capability, like THAAD. There is a larger system (DN-3), which sometimes gets confused with the aforementioned, for proper midcourse interceptions using an EKV.
Both are very likely to be using HTK technology.

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Only info I can find says HQ-19 is purely exoatmospheric midcourse, and that it's made to fit the HQ-9 battery family. If it's in HQ-9 family, it should have similarly a large warhead and sophisticated active + passive guidence systems with anti decoy functions, which brings it in alignment with an incoming projectile and then detonates the warhead to deflect it. Not hit to kill.

DN-3 seems to be almost analogous to US' GBI. It's more for anti ICBM and is possibly not road mobile, or certainly at least not shoot and scoot like HQ-9.