SM-6 versus DF-21

[DWReese]

I've played around with a lot of BMD battles over the past week. I know that the SM-3 needs tweaking, so let's set that aside for a minute. That leaves me with the terminal approach of the incoming DF-21 against the SM-6, so I have a few questions for other gamers:

Generally speaking, these incoming missiles are fast, and you may only get off one round of SM-6 missiles at the incoming DF-21s. Unlike the SM-3 which will completely destroy the missile if it hits it, the SM-6 rarely does so, usually only damaging the DF-21's trajectory just a little bit. In real life you probably won't have an endless supply of SM-6 missiles, so you can't just fire off your whole allotment, but a hit without killing it is usually sort of worthless.

So, since we can pick and choose how many we can shoot via WRA, how many SM-6s do you shoot at a DF-21? Obviously, it depends on how many are being shot at the target, but one hit from a DF-21 and the ship is dead, so this isn't something to be frugal with.

If I have an abundance, I have often fired as many as four SM-6s at a single DF-21. Generally, I have found that two is not enough, at least in my opinion.

Thoughts?

[thewood1]

What I have found is that a hit, even a minor hit is enough to deflect the RV away far enough to not be a threat. The odds are still greater than zero of the RV hitting something, but its very dependent on what intel says about expected threats.

[DWReese]

Wow! I have found things to be the exact opposite. I haven't seen very many times when the DF-21 was hit and suffered a trajectory change, when it still didn't hit the target ship. Even a significant hit on the DF-21 still seems to manage to hit the target. I'll have to look at that some more.

I just tried a bunch of SM-6s versus a total of four DF-21s. I had ordered, via WRA, the target ship to fire four SM-6s at each of the four DF-21s. That's a total of 16 missiles. The target ship carried a total of 32.

In most cases, the 16 SM-6s were able to kill 3 of the DF-21s, but the final one always seemed to sneak by. In most cases, the target ship would manage to get off another three SM-6s before the DF-21s were too close. In many cases, the last 3 were able to kill the last DF-21.

In the cases where the last 3 missed the target, the electronic countermeasures were often able to spoof the last DF-21, rendering it useless. In several cases, however, if the DF-21 was not spoofed, the ship was still saved when the weapon malfunctioned.

Finally, if the missiles failed to take it out, and the countermeasures didn't work, and the DF-21 didn't malfunction. the ship was hit by the DF-21 and sunk. If it wasn't sunk outright, which I figure was because the trajectory deviation, the ship would still usually suffer about 90 percent damage, and would eventually sink.

Note: I was hoping that 3 missiles fired at each DF-21might could do the trick, but in many cases all 3 of those missiles would miss, and the target ship would suffer the consequences by trying to be too frugal.

I believe that shooting 4 at the DF-21 is probably the best method to defend yourself.

The SM-6 seems to work very well.

[AceOfSpadeszzzzzz]

What I have found is that a hit, even a minor hit is enough to deflect the RV away far enough to not be a threat. The odds are still greater than zero of the RV hitting something, but its very dependent on what intel says about expected threats.

So a hit that does not destroy the fireball will increase its CEP, minor deviation = 1.5 * CEP, major deviation = 3 * CEP.

The CEP of DF-21D in the game is 4m. which means a minor will make it 6m, major 12m.

Compared to the size of a ship (DDG 51 class as an example, beam 20m based on wiki), even the 12m CEP(major) is still small enough. You need multiple (I would say at least 3-4 majors) deviations to save the ship. (If you do not consider the jamming effect & weapon malfunction)

Ref:
https://command.matrixgames.com/?p=4076
https://en.wikipedia.org/wiki/Arleigh_B ... _destroyer

[DWReese]

I just carried out another attack.

The SM-6 hit the DF-21 14 out of the 19 missiles fired, killing only two. Many of the hits caused SIGNIFICANT damage to the trajectory. 14 out of 19 seems a little excessive, especially when you consider that only 1 DF-21 was destroyed.

To thewood1's point, though, the second missile was jammed, but the third and fourth did miss the target ship (a Tico) by 295 feet and 56 feet. The combined effort caused 31 percent damage, and a huge fire. Obviously, the deviation is working, at least to some degree.

I do think that hitting the 4 missiles a total of 14 times should have resulted in more destruction, but I have no data to support that claim.

The SM-6s obviously work at shooting down these targets, but you don't have much time, or many opportunities to do so. If they get through, you are in trouble.

I'd like to know if there is anything written about expected munitions fired at weapons, such as the DF-21. If CMO is correct, then it will take at least 4 SM-6s per DF-21 to have a reasonable chance of survival. Plus, considering that most of these ships on carry 32 of these, attrition could become an issue real fast. If a second wave of 4 more DF021s were fired the Tico would be on the bottom of the ocean.

[caelunshun]

If CMO is correct, then it will take at least 4 SM-6s per DF-21 to have a reasonable chance of survival.

In general I would not trust CMO to accurately model highly tactical situations such as this, especially when modern weapons are involved. Most of the numbers in the formulae for weapon endgames (e.g., the 1.5x and 3x CEP increase, and especially spoofing probabilities with ECM / decoys) seem to have been pulled out of a hat, for lack of there being an available source or precedent in real conflicts.

Also keep in mind that unlike in CMO, real SM-3s do work reliably and would likely present a capable first line of defense against an incoming salvo.

[morphin]

I have also seen in the latest beta that despite beeing hit (Major) the target is hit (most of the time). I think this was not the case on earlier versions. I think it is worth to investigate this in deep

[thewood1]

"real SM-3s do work reliably and would likely present a capable first line of defense against an incoming salvo"

I like your optimism. SM-3s in real life have been fired so few times against real targets there is no way to back that opinion up. Even in tests, they have been much less than 100% unless the test is configured properly. Its all about geometry. There is a very narrow window in which a reasonable chance exists of an intercept. On top of that, there are a limited number of radars positioned around the world that can detect the launch and track with enough accuracy to cue the SPY-1 on to the missile in a limited window in space.

IOW, its extraordinarily complex and the SM-3 has not come close to proving itself as an investment. The situation in the Red Sea is actually a potential opportunity to test under combat conditions. I'm just not sure if any missiles being fired become exoatmospheric. Also, the geometry of the area doesn't lend itself to exoatmospheric engagements at close-by sea targets.

Now the SM-6 has been much more successful in endoatmospheric tests. Its also aligned better with the SPY-1s capabilities. But the speed and angle of entry have been a challenge for the SM-6 in intercepts. And the warhead is potentially an issue. At <100kg and blast fragmentation warhead against a potentially maneuvering 4000-6000 knot target, even a close detonation would most likely not completely destroy a large warhead. Its why the SM-3 has a solid intercept kill warhead. The goal of the SM_6 is most likely to damage the warhead and put it off course. Momentum is a bitch.

I have posted official test reports backing up my opinion on the SM-3 around the forums over the 4-5 years.

Here's one of the links I posted before. And these are test conditions where the firing ship(s) knew when the target was being fired, were positioned properly, had supporting tracking radar for target cueing, and knew the path of the missile.

https://missiledefenseadvocacy.org/miss ... st-record/

[DWReese]

In your testing, were there any changes to the success/failure of the SM-6 based on a variance of WRA firing distance settings? I've noticed that if left to the default, the SM-6 will generally get off two waves of shots at the incoming missiles. The first is fired when the missiles are about 130 miles away, and the second comes when the in coming missiles are under 20 miles away. That's just my observation. Does that match with your findings?

Also, since the hits that don't destroy the incoming missiles but do cause some kind of trajectory/flight variation, don't yo think that it should be a common practice of the target ship to immediately go to full speed so that it can't place as much distance between where the incoming missile was expecting to find the target, and to where the actual target is when the incoming missile closes in? It seems to me that the game programming seems to keep the target maintaining its pre-attack course and speed. If you're playing from the human side you can always make those changes yourself. It would be nice if the computer side could sense the attack also make that same maneuver.

[thewood1]

In my tests of Iranian AShBMs against SM-3/SM-6 armed DDG task forces, by the time the fireballs are detected, there is basically no time for any ship maneuver to make a difference. I have tried flank, 90 deg turns, stopping, etc. and its made no difference. This is with the DDGs detecting incoming vampires with their own SPY-1/SPY-6 radars.

btw, the biggest impact on avoiding AShBMs is killing the spotter. Not news to anyone paying attention, but killing or blinding the spotting unit results in not a single hit on a ship.

[DWReese]

Did you ever try the test using additional long-range detecting units? I've noticed that without those, the SM-3 can't even fire, but the SM-6 does manage to get off two waves. With those, I generally get several "hits" but most do not destroy the incoming missiles. They do cause course deviation. That is why I was suggesting the speed change. I figured that course deviation, plus a speed change by the target, could lessen the destruction aspect of the weapon. But, even a partial hit by these weapons is usually enough to completely destroy almost any ship, or at least put it out of action.

[thewood1]

I have no issues on SM-3s firing at Iranian AShBMs. About 50% hit rate. That seems reasonable to me. And when they hit, they kill.

[DWReese]

Could you please send me a sample scenario showing the SM-3 hitting something? I would sincerely like to compare the settings to see what is going on.



Thanks so much

[thewood1]

I have posted this multiple times. I don't need to email it to you. You can just download it.

6 x Khalij Fars AShBM fired around 23:18m to go. USN detection within a few minutes. All targeted and illuminated by Screen 1 DDGs. No fire because the are too low for SM-3s. The SM-3s don’t fire at the first batch because altitude of the arc is too low. But the second batch of 6 missiles are killed by SM-3s.

SM-6s start firing as the second batch of AShBMs are already killed by the SM-3s. The SM-6s either kill or deviate the RVs most of the time.

A few things to point out:
1) When Iran goes hostile, the clock pauses for about 30 seconds. Its always done this. I assume its spending a lot of cycles sorting through spotting, postures, and WRAs.
2) I think the reason the SM-3s don’t fire at the first AShBMs is the AShBMs never reach 100km in height. As the target USN ships get closer the parabolic arc of the AShBMs goes higher and allows them to enter the intercept zone of the SM-3s.
3) WRAs are critically important in this scenario. I have had to fiddle a lot with SM-6s to make sure they aren’t all used up on the first wave of attacks. I let SM-2s and ESSMs absorb most of that, but not all. If the SM-6s get used up early, you will lose at least a DDG.
4) I have thought about adjusting the AShBMs so that they wait a little longer. But, as you can see, that means they will get targeted by SM-3s.

You can play around with geometry and let a few ships get sunk. But if use a typical expected engagement in the straight, it is almost what the SM-3s and SM-6s were built for. I included the ini file.

[thewood1]

I would strongly suggest removing your personal email or the mod should do it. Webcrawlers will jump on it and will spam you incessently.

[blu3s]

Keep in mind the huge differences of the WEZ btw SM3 and SM6.

[thewood1]

While interesting, I'm not sure how relevant that is to the discussion.

[blu3s]

Because not all ASBM reach the altitude/geometry to be engage by an SM3.

[DWReese]

thewood1,

Thanks for the scenario. As your scenario shows, the SM-3 can hit some targets. I tried the same setup with the DF-21 family and it is a no-go. It's still the late-stage failure to detect the missile issue. If you have any examples of the DM-3 hitting a SF-21, that would be great.

Thanks

[thewood1]

Have you posted anything on this other than phone picture? Post a scenario that shows your issues.