Efficacy of the SM-3 Against Countermeasures?

[Exosphere]

I just saw a video that claims the SM-3 isn't particularly effective because countermeasures could be used against it, and it would be unable to discriminate between a "balloon" style countermeasure and the real warhead (or the "balloon" countermeasure could actually contain the warhead inside of it). Since I apparently can't link to videos until I have ten posts, the video was created by the Union of Concerned Scientists and is called "Missile Defense Countermeasures" on YouTube.

So... what do you guys think? Is this plausible or not?

 

[StobieWan]

If you're making the other side sacrifice payload for countermeasures, you're degrading the threat a touch before they've even left the factory...

Countermeasures of the sort you've described have been around for decades - the UK update to their Polaris warheads, Chevaline, is still (as far as I'm aware) the most sophisticated collection of penetration aids fielded to date.

There's ways and means of decoying missiles but a balloon decoy will have a different mass and react differently when falling - there should be ways to break those out from the warhead I'd have thought.

 

[Exosphere]

If you're making the other side sacrifice payload for countermeasures, you're degrading the threat a touch before they've even left the factory...

Countermeasures of the sort you've described have been around for decades - the UK update to their Polaris warheads, Chevaline, is still (as far as I'm aware) the most sophisticated collection of penetration aids fielded to date.

There's ways and means of decoying missiles but a balloon decoy will have a different mass and react differently when falling - there should be ways to break those out from the warhead I'd have thought.

So countermeasures do react differently in space? The impression I had gotten from the video is that, in a vacuum, countermeasures and the warhead itself will move in the same manner because there is no atmosphere to separate them. I've read a few papers produced by the Union of Concerned Scientists on the matter, and they seem to be very "countermeasures uber alles" with regards to ballistic missile defense -- i.e. the general idea is that BMD doesn't work because countermeasures are virtually indistinguishable from the real thing.

On a side note, their aversion to BMD doesn't seem to be new -- I saw a TV ad from the '80s criticizing the Star Wars program.

 

[My2Cents]

I assume you mean this one [nomedia="http://www.youtube.com/watch?v=gNSR7dXHdCY"]Missile Defense Countermeasures - YouTube[/nomedia]


The Union of Concerned Scientists extremely anti-ABM, and therefore tends to oversimplify the issue. For example, while they claim the system would be ineffective, they also support the claim by Russia that putting a system in southeastern Europe to intercept any Iranian missiles aimed at Europe threatens Russia’s nuclear deterrent. The system proposed has far too few interceptors to make more than a dent in a Russian attack, they just have too many missiles, with decoys. It will be much more effective against a limited attack from Iran.

1. To be effective the number of effective decoys has to exceed the number of interceptors by at least a factor of 2. If less than that, you can generally just shoot all the targets, decoys and warheads alike, assuming 2 missiles per target.
   
2. The video assumes that the missile can just hide inside a balloon surrounded by other balloons. However the once inside the balloon the RV can no longer maneuver, so the RV in its balloon becomes the only object that is still following the same trajectory as the missile upper stage that it separates from. Modern surveillance radar can distinguish shape, so the inflated balloon decoys need to be the same size and shape as the target, or slightly larger to be able to contain the warhead, if that is your strategy. The deployment mechanism has to be sophisticated enough that the decoy separation cannot be distinguished from the warhead deployment by the surveillance radar. The upper atmosphere doesn’t just stop at some arbitrary elevation as assumed in the video, but extends to 500km to 1000km depending on solar activity, so the motion of the decoys relative to the warhead will be effected because they are several orders of magnitude less dense and slow much faster in the extreme upper atmosphere after separating from the missile.
   
3. The decoys cool much more rapidly in space allowing them to be discriminated from the warhead by temperature. The UCS propose getting around this by heating the decoys electrically, but this requires batteries and wires to generate the heat, which in turn require a much tougher balloon that can support the weight suspended inside it. This adds a lot to the size and weight, which cuts down on the number of decoys that can be carried.
   
4. The decoys need to be on believable trajectories that don’t end in the middle of nowhere. A successful decoy systems will probably have to behave as a MIRV, except only one of the objects will be a warhead, and the rest are decoys.
   
5. The decoys and their deployment system need to be carried by the same missile to prevent discrimination by tracking, so a higher throw weight is required. So far 3rd world missiles barely have enough for the warheads they can create. Only the US, Russia, UK and France have missiles (MIRVed ICBM with only 1 warhead) large enough to carry a significant payload of decoys. It is, of course, possible to mimic this with multiple launches with dummy warheads, but now it is getting VERY expensive for all those missiles.
   
6. The assumption by the authors that any system that is not capable of stopping absolutely all the warheads in any conceivable attack is absolutely useless. (Other assumptions that Union of Concerned Scientists make are that total nuclear disarmament is the only possible solution {they object to ABMs because it tends to undermine this assumption}, that the USA is solely responsible for the continuing arms race, and that the USA needs to unilaterally disarm its nuclear forces in order to reassure the USSR/Russia that they can also disarm.) The biggest advantage to ABM systems is the ability to deal with small attacks, the accidental launch scenario and the small arsenal (Iraq and North Korea) scenarios. It reduces the use-it-or-lose-it defensive philosophy and leaves attacker potentially faces the embarrassing prospect that the defender may be able to just thumb his nose at him after shooting the missiles down, and then call him (the attacker) before the World Court for the attempt.
   
7. The bomblet scenario is just a MRV and can defeat a limited number of ABMs, but ignores design problems that need to be overcome. Now each of the objects is a warhead that needs to be capable of withstanding reentry and mount a radar fuse and fast dispersal mechanism for a low altitude release of the chemical or biological contents, and carry enough material to be effective. In short, each of those bomblets is going to have to be nearly the size of a full warhead RV, you are not going to be packing 100s in the same space. It’s also only likely to work once, then nuclear equipped interceptors will also be made available to fry the lot.
   
8. It should be noted that according to the author’s commentary the video dates from the year 2000, well before when testing started.

 

[Exosphere]

[*] The video assumes that the missile can just hide inside a balloon surrounded by other balloons. However the once inside the balloon the RV can no longer maneuver, so the RV in its balloon becomes the only object that is still following the same trajectory as the missile upper stage that it separates from. Modern surveillance radar can distinguish shape, so the inflated balloon decoys need to be the same size and shape as the target, or slightly larger to be able to contain the warhead, if that is your strategy. The deployment mechanism has to be sophisticated enough that the decoy separation cannot be distinguished from the warhead deployment by the surveillance radar. The upper atmosphere doesn’t just stop at some arbitrary elevation as assumed in the video, but extends to 500km to 1000km depending on solar activity, so the motion of the decoys relative to the warhead will be effected because they are several orders of magnitude less dense and slow much faster in the extreme upper atmosphere after separating from the missile.[/list]

I read a paper by Lewis & Postol (who write a lot for the UCS regarding BMD) claiming that the AN/SPY-1 radar doesn't have the resolution and S/N ratio capabilities to discriminate between decoys and warheads at operationally significant ranges. The paper utilized the radar equation (i.e. it seemed relatively well thought out -- they didn't just claim "it can't be done!" with no proof) to prove that the SPY-1 couldn't do the job. I'd link to the paper if I could, but as of yet I don't have that ability. So... can the SPY-1 discriminate between decoys and warheads? At the very least, the UCS doesn't seem to think so. I'm not sure how much they know about the SPY-1 (they're not connected to the military, and so are not privy to classified information), but like I said, they didn't just make unsubstantiated claims -- they modeled the SPY-1's capabilities, at least as accurately as they could with the information they have.

Also, I know that the atmosphere extends quite a ways up (fun fact: the International Space Station, which orbits at an altitude of about 420 kilometers (higher than the apogees of most IRBMs) retracts its photovoltaic arrays while on the night side of the Earth to reduce atmospheric drag and limit orbital decay), but I wasn't aware that it was that severe. Obviously, even very little residual atmospheric drag would separate decoys and warheads given enough time, but since most IRBMs only spend a few minutes outside the thick portion of the atmosphere, I always assumed there wasn't enough time for the warheads and decoys to separate appreciably due to residual drag.

 

[colay]

Navy is aware of the capabilities and limitations of SPY-1 hence the ongoing next-gen AMDR program. There has been mention of an intriguing possibility that multiple AMDR sets could be linked together, providing performance levels of a much larger radar.

 

[My2Cents]

I read a paper by Lewis & Postol (who write a lot for the UCS regarding BMD) claiming that the AN/SPY-1 radar doesn't have the resolution and S/N ratio capabilities to discriminate between decoys and warheads at operationally significant ranges. The paper utilized the radar equation (i.e. it seemed relatively well thought out -- they didn't just claim "it can't be done!" with no proof) to prove that the SPY-1 couldn't do the job. I'd link to the paper if I could, but as of yet I don't have that ability. So... can the SPY-1 discriminate between decoys and warheads? At the very least, the UCS doesn't seem to think so. I'm not sure how much they know about the SPY-1 (they're not connected to the military, and so are not privy to classified information), but like I said, they didn't just make unsubstantiated claims -- they modeled the SPY-1's capabilities, at least as accurately as they could with the information they have.

1. When was the paper published?
2. What version of the AN/SPY-1 were they looking at? There have been several upgrades and a lot of tweaks over the years.
3. What were their criteria for discriminating between a warhead and a decoy? It is easy to prove the radar can or can’t discriminate just by using different criteria.

Always remember the proverb -- “figures don't lie, but liars can figure” -- applies to both sides.

 

[StobieWan]

What's the seeker like in the SM3? I thought it was active all the way - with a data link - it may be that the seeker head can do some last minute sort and sift?

 

[Exosphere]

1. When was the paper published?
2. What version of the AN/SPY-1 were they looking at? There have been several upgrades and a lot of tweaks over the years.
3. What were their criteria for discriminating between a warhead and a decoy? It is easy to prove the radar can or can’t discriminate just by using different criteria.

Always remember the proverb -- “figures don't lie, but liars can figure” -- applies to both sides.

I'm currently looking for the study, but I did find something else related to it while perusing the author's website in search of the paper. I can't post links yet, so just search for "Mostly Missile Defense Why the Current GMD System's Radars Can't Discriminate".

 

[Exosphere]

What's the seeker like in the SM3? I thought it was active all the way - with a data link - it may be that the seeker head can do some last minute sort and sift?

It's got an imaging infrared seeker that's been upgraded over the last few years to have better discrimination abilities and two-color detection. It does receive data linked updates from ground, but I've heard some concern that the IIR seeker can't discriminate between warheads and decoys, so if that's the case, it may need updates from a ground sensor capable of doing so. The other concern I've heard from the UCS/Postol/Lewis et al is that ground radars can't discriminate either.

Basically, the UCS and Lewis/Postol are of the opinion that current BMD tests either aren't rigorous enough, or are outright rigged. They claimed one of the early GMD tests in the DEMVAL phase was rigged because the warhead had an emitter on it to designate it as the target to the interceptor, that the early tests were done with the sun illuminating the targets to aid discrimination, and that the decoys used in the two tests where decoys were present weren't realistic, because they didn't correctly match the signature of a real warhead (I.e. they weren't advanced enough decoys).

 

[Exosphere]

I know I'm committing the twin deadly Internet sins of reviving a necro thread and double-posting, but I thought of something related to the subject of the thread, and thought that continuing a dead thread would be better than starting an entirely new one about the same topic.

The original reason I created the thread was the DF-21D "hype missile" . One issue that worried me was that the DF-21D could use decoys to defeat an SM-3 based defense system. However, I considered what My2Cents wrote about decoys most likely being similar to a MIRV system, and I just recently saw an old USAF video about Minuteman decoys called "1988 USAF video: ICBM penetration aids" (which I still can't post due to the whole ten posts before you can post links rule :flaming ), which also suggested that decoys would be used like MIRVs (I.e. each decoy would be released at a specific window by the post-boost bus, with the actual warheads released somewhere between the decoys).

From what I understand, when a MIRV (or MIRV-like eystem, such as a decoy system) releases its payloads, each individual payload is put on a different trajectory. For example, the bus might release one decoy, maneuver to a different trajectory, release a warhead, maneuver again, and release a second decoy (the USAF video specifically shows the bus maneuvering between releases). Since this is the case, it would seem like decoys would be of limited utility on a system like the DF-21D. An aircraft carrier is extremely small compared to an ocean or a region of land in which multiple MIRV warheads might target, so it would seem like any decoys used by the DF-21D would be relatively easy to discriminate, as they would follow trajectories that end nowhere near the carrier. Thus, it could be assumed that the real warhead is the one which has a trajectory ending at the carrier. Once this is known, the SM-3's data link could be used to designate which of the potential targets it should hit.

Of course, all of this is just conjecture on my part. Is my scenario realistic, or is there something regarding MIRVs, decoys, or the SM-3's targeting system that I'm misunderstanding? Also, sorry again for reviving a necro thread and triple-posting (!!). I just thought it would be better to use an existing thread rather than create a new one.

 

[RobWilliams]

It's fine mate, at 3 weeks it's not exactly necro and we only frown upon multiple posts if posted in rapid succession because it's generally an attempt to rapidly boost post count.

You're fine, s'all good.

 

[StobieWan]

I know I'm committing the twin deadly Internet sins of reviving a necro thread and double-posting, but I thought of something related to the subject of the thread, and thought that continuing a dead thread would be better than starting an entirely new one about the same topic.

The original reason I created the thread was the DF-21D "hype missile" . One issue that worried me was that the DF-21D could use decoys to defeat an SM-3 based defense system. However, I considered what My2Cents wrote about decoys most likely being similar to a MIRV system, and I just recently saw an old USAF video about Minuteman decoys called "1988 USAF video: ICBM penetration aids" (which I still can't post due to the whole ten posts before you can post links rule :flaming ), which also suggested that decoys would be used like MIRVs (I.e. each decoy would be released at a specific window by the post-boost bus, with the actual warheads released somewhere between the decoys).

From what I understand, when a MIRV (or MIRV-like eystem, such as a decoy system) releases its payloads, each individual payload is put on a different trajectory. For example, the bus might release one decoy, maneuver to a different trajectory, release a warhead, maneuver again, and release a second decoy (the USAF video specifically shows the bus maneuvering between releases). Since this is the case, it would seem like decoys would be of limited utility on a system like the DF-21D. An aircraft carrier is extremely small compared to an ocean or a region of land in which multiple MIRV warheads might target, so it would seem like any decoys used by the DF-21D would be relatively easy to discriminate, as they would follow trajectories that end nowhere near the carrier. Thus, it could be assumed that the real warhead is the one which has a trajectory ending at the carrier. Once this is known, the SM-3's data link could be used to designate which of the potential targets it should hit.

Of course, all of this is just conjecture on my part. Is my scenario realistic, or is there something regarding MIRVs, decoys, or the SM-3's targeting system that I'm misunderstanding? Also, sorry again for reviving a necro thread and triple-posting (!!). I just thought it would be better to use an existing thread rather than create a new one.

Defeating DF21 starts before it's launched - there's a whole kill chain starting with the detect phase that can be dicked with before the missile lights it's first stage. Post launch, there's a ton of counter measures that overlap with SM3. SM3 in this scenario isn't invincible - but it's a useful layer the enemy has to degrade by giving away payload to countermeasures etc.

 

[Exosphere]

Defeating DF21 starts before it's launched - there's a whole kill chain starting with the detect phase that can be dicked with before the missile lights it's first stage. Post launch, there's a ton of counter measures that overlap with SM3. SM3 in this scenario isn't invincible - but it's a useful layer the enemy has to degrade by giving away payload to countermeasures etc.

You mean the DF-21D isn't an unbeatable "carrier killer" that will reduce everything that gets within 2,500 nautical miles of the Chinese coast to a burning hulk in a single hit and cannot possibly be spoofed or defended against?

Darn. That must mean some of the blogs and forums on teh Interwebz are wrong...

Anyways -- besides intercepting the missiles themselves, could the SM-3 Block IIA be used to intercept the imaging satellites China might use to locate carriers? I know the current version of the SM-3 can only hit satellites that are at very low altitudes, but the IIA has a much greater burnout velocity -- the "low estimate" is 4.5 kilometers per second, allowing it to reach an altitude of at least 1,450 kilometers (an altitude range which includes all of China's Earth observation satellites). Considering that satellites travel along relatively constant orbital paths, cannot conduct evasive maneuvers like aircraft, cannot utilize countermeasures, and can be relatively easily seen by IR sensors (i.e. they're not LO), it would seem like both the SM-3 Block IIA and the GMD (which has an even higher burnout velocity) could be used to intercept satellites. At a minimum, the Union of Concerned Scientists is... well... "concerned" about it (I'm not using a lot of their publications for any particular reason; it's just that they seem to be all over anything related to ABMs and space warfare). The only issue I could see would be inadvertently generating an ablation cascade through the debris created by the impacts. USA 193 was at a low enough altitude, in an unstable orbit, that the debris created by the "shootdown" wasn't a problem, but anything higher in LEO might be problematic. The UCS seems to think so at least, which is why they seem to want to limit the burnout velocity of future versions of the SM-3 to prevent it from being used as an ASAT, as they believe the stated reason for the higher burnout velocity (boost phase intercept) would be virtually impossible to do.

http://www.ucsusa.org/assets/documents/nwgs/2011-winter-anti-satellite.pdf

 

[StingrayOZ]

From what I understand, when a MIRV (or MIRV-like eystem, such as a decoy system) releases its payloads, each individual payload is put on a different trajectory. For example, the bus might release one decoy, maneuver to a different trajectory, release a warhead, maneuver again, and release a second decoy (the USAF video specifically shows the bus maneuvering between releases). Since this is the case, it would seem like decoys would be of limited utility on a system like the DF-21D. An aircraft carrier is extremely small compared to an ocean or a region of land in which multiple MIRV warheads might target, so it would seem like any decoys used by the DF-21D would be relatively easy to discriminate, as they would follow trajectories that end nowhere near the carrier. Thus, it could be assumed that the real warhead is the one which has a trajectory ending at the carrier. Once this is known, the SM-3's data link could be used to designate which of the potential targets it should hit.

An advantage of SM3 is that it can intercept early boost or early mid trajectory (Depending), where most decoys are not used or less effective and unrealistic and there aren't a whole lot of options. Terminal decoys as you have pointed out is not hugely effective with conventional weapons or in a sea based context because you know where they are trying to hit. But still adds complication to a very difficult job.

Much harder for a nuclear attack (or city attack), where any/all of the MIRV could be devastating wherever they go. The decoys just have to spread out just enough to require a huge commitment.

As stobie pointed out, the most effective part, is killing it before launch which is much more effective and reliable. SM3 (and PAC3 etc) and other systems however, do make it much less likely of a successful attack. With these kind of attacks, you would want to ensure your pretty confident of it working, as the resulting repercussions would be pretty major.