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What goes up must come down

While watching news coverage of the fighting between Israel and Hezbollah, I saw some clips of incoming rockets descending on Israel. I briefly wondered why Israel wasn't using Patriot missiles or otherwise trying to shoot down the rockets. Then I thought about it, and came to the conclusion that the Israelis knew what they were doing.

What a lot of people tend to forget is that anti-aircraft (and anti-missile) weapons aren't death rays. An airplane or missile that gets shot down is just that -- not destroyed, shot DOWN. It comes down to earth in various pieces of various sizes in various places. The old video game "Missile Command" never dealt with shrapnel.

And when that object is destroyed by a missile, then there's even more explosives and debris raining down.

Anti-missile warfare is a very challenging science. You have to balance the potential harm of letting the incoming missile hitting its target or risk shooting it down -- in essence, weighing the potential damage to where it's headed against where it will land versus what will be below it when you attempt to destroy it. For example, a missile that looks like it will overshoot the city and land in the ocean should be left alone. On the other hand, one heading for an oil refinery after overflying a hunk of desert desperately needs to be stopped.

Complicating the calculus are a couple of nasty variables. The missile is moving -- the area under it is constantly changing. It can cross vacant areas, farmlands, schools, hospitals, and crowded neighborhoods on its way to its final destination. And it's moving fast -- the decision to shoot or ignore must be made very quickly.

Also, sometimes the missiles miss. They are usually programmed to self-destruct after missing their target, but once again you have the problem of shrapnel and debris falling back to earth.

The defenders have a few advantages. They tend to be emplaced in familiar land, and often have time to map out the area, designating which places are safer than others to shoot down missiles over. Also, in Israel's case, the missiles are almost entirely ballistic and unguided, meaning that once launched, their path is largely predictable, a matter of applied math. To the best of my knowledge, the only guided missiles fired by Hezbollah have been the anti-ship missiles that sank an Egyptian freighter and damaged an Israeli corvette.


Comments (33)

Actually, katyusha's are ro... (Below threshold)
jim:

Actually, katyusha's are rockets and not missles. The difference is in size. The rockets are too small to be targeted by the patriots.

Jay-Quick comment ... (Below threshold)
roanoke:

Jay-

Quick comment the trajectory of the katushka { whatever the spelling is...} is too low to the ground to be taken out by the Patriot missile.


What I'd be more worried about-while we are on the subject of what goes up must come down- is what is insuring that the Syrian Air Force stays neutralized. I'd be mighty wary of sending in ground troops without that controlled for somehow.


Yeah, The Patriot is... (Below threshold)
lord cranberry:

Yeah,
The Patriot is not designed for or capable of destroying a Katyusha rocket. It is however, capable of destroying some of Hezballahs' larger missiles.

One of the more vile tactic... (Below threshold)

One of the more vile tactics of the Hezbollah/Lebanese Army/Iranian intelligence on the border was that they'd fire anti-aircraft guns at Israeli border towns so that the flak would *intentionally* rain down on civilians.

When challenged on this, the Lebanese government would shriek about the IAF overflights, but not admit the fact that the anti-aircraft guns had NEVER taken down an IAF flight.

Why? Because the AA were never intended to hit the planes. They were fired to rain down shrapnel on Israeli civilians.

And the UNIFIL "observers" hanging out with the Hezbollah while this was going on? Well, when you're a welcome guest/human shield, it's considered rude to bad-mouth your host.

Even in ideal circumstances... (Below threshold)
gattsuru:

Even in ideal circumstances, the Patriot has a very low accuracy rate. They're fairly successful : a typical Patriot barrage can will deflect or destroy a target nearly 97% of the time. But you use a lot of missles to do this - roughly three for every incoming one - if you're attempting to destroy the missle's warhead, you're not in much luck. An optimistic analysis suggested only around a 20% success rate, and the Israel's were talking about one

It does what it's supposed to do - it's an excellent tool for deflecting missles or taking down planes. But while it's the best tool for the job around, it's not perfect.

All of the systems are based around an anti-aircraft missle. Other than the PAC-3 missles, they aren't even designed to impact the target themselves (relying instead on the explosive yield), and PAC-3 is not really fast enough to reliably destroy or deflect these sort of targets.

Patriots are very expensive... (Below threshold)
aardvarknav:

Patriots are very expensive missiles and more than one Patriot is usually fired at an incoming missile. It doesn't make sense to fire them at very inexpensive rockets coming in on a low trajectory. The question to ask is how the Israelis are using their Firefinder systems to counter the rockets. You seem to be putting a lot of weight on damage caused by the debris and shrapnel from rockets destroyed in the air. The effect of shrapnel and debris is significantly less than letting a system explode on the ground. Look at the amount of anti-aircraft artillery and missile fire over Baghdad in the first Gulf War and over Hanoi and Haiphong during Linebacker II. Debris and shrapnel falling on the ground did not seem to be a factor in decisions to keep trying to destroy incoming aircraft or other weapon systems. We didn't see reports of significant damage caused by debris and shrapnel after the wars.

aardvarknav's right. Every ... (Below threshold)
Matt:

aardvarknav's right. Every time you fire a Patriot, you can ring the cash register for around $600,000. Why waste an obviously finite supply on something that while nasty, is not massively destructive. You probably wouldn't hit it anyway.

I do notice, however, that the terrorists are continuing another of lovely tactics. The Katyusha warheads seem to be packed with ball bearings to ensure maximum carnage.

Found <a href="http://www1.... (Below threshold)
Lee:

Found this info recently on Israel's ARROW II interceptor and ARROW anti-ballistic missile system. Not sure of the authenticity of this info and web site -- the site looks old and somewhat outdated.

Every time you fire a Pa... (Below threshold)
gattsuru:

Every time you fire a Patriot, you can ring the cash register for around $600,000

Where are you getting that number from?

Last I worked near the system, an individual MIM-104 series cost over $1 million, usually between $1.2 and $1.3 mil depending on varient. Not sure what the final number for PAC-3 missiles were, but I know it jumped between four and two million each.

Expensive at any rate. Thin... (Below threshold)
914:

Expensive at any rate. Think of the effects if they were filled with a chemical agent?

Also keep in mind that just... (Below threshold)
JSchuler:

Also keep in mind that just because something is dropped from a high altitude does not mean that it will be fatal or even particularly injurious if it hits a person. Everything has a terminal velocity, and it's likely that an irregular piece of shrapnel tumbling for a significant period through the atmosphere will be traveling at a low enough velocity that it probably will only result in minor injuries if it hits someone.

You're probably right, Gatt... (Below threshold)
Matt:

You're probably right, Gattsuru. My father worked peripherally on the Patriot with Raytheon. but it has been a while and I wasn't accounting for time and improvements. $3-$4 million makes my point nicely, though, thanks!

Fox News had reported Frida... (Below threshold)
aardvarknav:

Fox News had reported Friday evening that the Israeli Patriots cost about $1M. I'm surprised the Israelis haven't asked for an emergency shipment of the C-RAM system, an Army version of the Navy's Plalanx point defense system. From what I can find on the Internet it looks like there are at least 6 in Iraq protecting the Green Zone in Baghdad. It looks like the peformance is getting decent results.

as others have noted Katyus... (Below threshold)
K:

as others have noted Katyusha and similar rockets have a short flight time and flat trajectory that makes interception very difficult.

They could of course be eventually stopped but only by very advanced means. It simply isn't a military goal we should spend billions upon. The same money can be used more effectively.

These assault rockets are a variant of artillery. The rocket user thus avoids some of the limitaions of guns but faces some new problems.

Artillery is heavy and vulnerable to air attack. Big guns are tough to move or mass without detection. Guns have a low firing rate because or reloading. Rockets are not reloaded so many can be triggered at once in an awesome barrage. Often the gun's range is shorter.

But unguided rockets are not accurate and each round is heavier so overall you move more weight to the battle area. The rocket costs more than the artillery round - which may or may not be a factor.

The difference between a ro... (Below threshold)
Mark L:

The difference between a rocket and a missile is that a missile is guided and a rocket is not. Even an ICBM has a guidance system, although it is based on where it thinks the target is rather than taking sensor data.

The best way to take out rockets, btw is to occupy the ground which is being used to fire them. And the best tool for occupying ground is still the infantryman.

A $4 million missile to tak... (Below threshold)
John S:

A $4 million missile to take down an unguided $200 rocket? Spending that would only make sense to the U.S. military.

PAC-3 is not really fast... (Below threshold)
Slartibartfast:

PAC-3 is not really fast enough to reliably destroy or deflect these sort of targets

If you mean it's not fast enough to be able to achieve intercept in the target rocket's pre-impact timeline, that may be correct. If you're saying it lacks the energy to destroy said rockets, you're dead wrong.

Other than that, lots of good points. You don't send a 6-inch-diameter Mach 5 missile costing millions of dollars to shoot down a 3-inch-diameter rocket, sure. As far as I can tell, Israel's missile defense eggs are all placed in the Arrow basket, and Arrow is probably not the right weapon for the job. The right weapon for this job is more likely counterfire artillery or guided missiles.

Even an ICBM has a guidance system

You misspelled especially. ICBMs have hell's own guidance system; they just don't have homing guidance (except, arguably, for Pershing II, which is no longer with us). ICBMs are guided by their extraordinarily accurate navigation systems. Some of these, I'm told, did midcourse star sightings so that position errors that were due to inertial attitude errors could be taken out prior to RV insertion.

JFTR, I've worked on both THAAD and the development effort that led to PAC-3, and I think most of the points to the effect that these are not the right tools to deny these missiles are correct. Obviously. They're probably good for shooting down some of the larger rockets, but (again, as others have pointed out) there might not be any good intercepts to be accomplished if by hitting the target you rain debris all over residential areas.

The reason why Israel is no... (Below threshold)
chsw:

The reason why Israel is not firing the Patriot is simple: They will be needed if and when Iran fires nuclear-tipped missiles at Israel.

chsw

If you mean it's not fas... (Below threshold)
gattsuru:

If you mean it's not fast enough to be able to achieve intercept in the target rocket's pre-impact timeline, that may be correct. If you're saying it lacks the energy to destroy said rockets, you're dead wrong.

Ah, sorry if I wrote that incorrectly.

On a hit, the PAC-3 can easily destroy Hezbollah's normal missiles despite the PAC-3's smaller explosive yield - unlike the MIM-104x series, the PAC-3 is designed as a hit-to-kill, and is fairly effective for a design that's considered "hitting a bullet with a bullet". These things can fairly reliably disable planes (although the MIM-104a is usually prefered for that), they're going to blow a rocket out of the sky if they hit.

Sadly, the PAC-3's high density and lower amount of fuel make is much less effective at hitting fast targets. While it's possible that a couple may be launched fast enough, a majority aren't going to get in the air and at the rocket before it's hit the target.

Sadly, the PAC-3's high ... (Below threshold)
Slartibartfast:

Sadly, the PAC-3's high density and lower amount of fuel make is much less effective at hitting fast targets.

I'm not sure what you mean by this. PAC-3 is just about as agile an airframe as I've ever seen. The predecessor to PAC-3 that I worked on used the same technique for maneuvering and it had at least a 50g capability, and as for response time...PAC-3 uses squibs, not fins. The squibs have a response time, IIRC, in the single-digit milliseconds. The squib induces a step angle of attack, and the g-response to that is pretty rapid. This is all based on memory, mind you, that's a couple of decades old.

Sure, it's not made to hit ICBMs, but that's not quite the same thing as saying it's not suitable for fast-moverd.

movers, rather.... (Below threshold)
Slartibartfast:

movers, rather.

Hm... I was pretty far awa... (Below threshold)
gattsuru:

Hm... I was pretty far away from the system by the time the PAC-3 upgrades were finalized, but I was fairly sure the PAC-3 had a slower maximum speed and acceleration than the MIM-104x series.

I'd assume it would have to be (very) agile to hit a target moving so fast, but agility over a few meters doesn't help much when the target rocket is too far away or moving too fast to intercept.

I know that it was not used as a matter of policy against air-to-surface missiles because of its shorter range and slower maximum speed for a good couple of years.

Has that changed?

Hm... I was pretty far a... (Below threshold)
Slartibartfast:

Hm... I was pretty far away from the system by the time the PAC-3 upgrades were finalized, but I was fairly sure the PAC-3 had a slower maximum speed and acceleration than the MIM-104x series.

Well, Globalsecurity.org has both PAC-2 and PAC-3 listed as being Mach 5 missiles. What that means, though, is a good question. I doubt you'll find burnout velocity in the public domain. I'd guess, though, that PAC-3 actually accelerates faster than PAC-2. PAC-3's younger brother burned out in something like 8 seconds, IIRC. Of course, neither of them lays a glove on Sprint, but that's old, old, old.

agility over a few meters doesn't help much when the target rocket is too far away or moving too fast to intercept

I'd say that all depends on how accurate the waypoint is. And I'd guess that PAC-3 has waypoint updates; THAAD does. Every missile has a maximum target dispersion that it can take out in terminal phase; I'd guess PAC-2's is probably larger than that of PAC-3, because PAC-3 actually has to use up a finite set of squibs to divert over to the target. PAC-2, of course, uses fins.

PAC-3 does have a fragmentation warhead for use against aircraft; I think someone upthread mentioned that it wasn't so good in those cases. I'd guess PAC-2 would be used preferentially, if there were a choice, for cost reasons.

roanoke, don't worry about ... (Below threshold)
Ariya:

roanoke, don't worry about the Syrian air force... Israel has complete control of the skies. They are pretty much lined up off the coast of Lebanon for any missions. A long waiting line. ;)

The <a href="http://www.def... (Below threshold)
mesablue:

The THEL will take down rockets and artillery shells.

It is close to being deployable, this would be a good time for in theater testing.

Also, there has never been a defense against artillery outside of eliminating the source so this would be a significant advance.

There have been some very g... (Below threshold)

There have been some very good comments in this thread so far - and some very uninformed ones as well.

I currently work software development for the Patriot program, and would like to add a couple of comments of my own:

1) I've physically seen PAC-3 pull some maneuvers in flight that would drop your jaw to the ground. As far as maneuvarability goes, I have no doubt it could hit these incoming rockets.

2) I have to admit ignorance on speed. It's quite possible that PAC-3 isn't fast enough to hit one of these rockets, but I would tend to doubt it.

3) The idea that these rockets fly a trajectory too low for Patriot to hit it is total horseshit. This is an area I've specifically worked on for Patriot. They *prefer* to shoot at things higher in the air, but that's because it's further away from the area they're defending and therefore safer. They can hit targets pretty damn low in the atmosphere - probably lower than an unguided missile would be able to fly for fear of hitting an obstacle on the way to its target.

4) Gattsuru is very correct - Patriot has an obscenely high success rate (contrary to news reports). It does, however, almost always require multiple missile firings for one "kill". It's very ineffecient, but the system was designed to be *SURE* that it's target got shot down. A typical fielded Patriot battalion doesn't have anywhere close to the number of missiles it would take to shoot down all of these rockets, and the cost to do so would be prohibitively high.

5) I think there's a major misconception here about how Patriot works to begin with. You don't just plop down a Patriot launcher/radar and get instant defense of an entire bubble around that unit. Patriot is an "asset" defender, not an area defender. You have do decide up front what you want to protect within your zone. If you do it right, it'll protect those areas amazingly well - but anything outside of those areas it will ignore. This isn't anything "broken" with Patriot, it's just how it was built.

6) As has been mentioned, shrapnel almost certainly has nothing (zero, zip, nada) to do with it. Shrapnel falling from the sky wouldn't even bother anybody who was indoors, which most people would be in these situations (the government is almost certainly encouraging people to stay indoors, as they do in almost all "air raid" conditions). Exploding warheads, on the other hand, *DO* pose a threat to people indoors. There's no question here which is preferable - if there were an effecient system to do it, these rockets would be getting shot down. The key here is "effecient".

I'm going to stand up for a second and defend Patriot because it's a DAMN good system for what it was designed to do - but that last part is key. It's not a magic bullet that will protect you from anything and everything. There are many kinds of attacks which it is simply not suited to defend against, and this situation is definitely one of them.

In this case, given the low tech nature of the rockets in question, it's easier and more effective to protect the civilians by just getting them to bomb shelters when the rockets start flying. As for infrastructure, it's cheaper to just let the damage happen and rebuild.

Russell, I'd guess that the... (Below threshold)
Slartibartfast:

Russell, I'd guess that the only way a Patriot wasn't fast enough would be that the target had a very short trajectory, and there would therefore be insufficient time to acquire, obtain a fire control solution, launch and intercept before the target reached its target.

To me, Mach 5 means something on the close order of 1.5 km/s, which is not inconsiderable. THAAD is, IIRC, considerably faster (in terms of straight-line speed), but its burnout velocity is classified.

Russell: Excellent comment... (Below threshold)
SShiell:

Russell: Excellent comments. I am a retired Air Force fighter pilot with 1800+ hours in F-4s and 800+ hours in F-111s. In all my years of flying, the one threat I did not want to face was the Patriot. And in fact have briefed more than one combat mission scenario where the greatest fear was not having an operable Mode IV (friendly identification transponder for the civilians in the audience) and having to face potential engagement by Patriots when crossing back into "Good Guy" territory after a mission.

As I see it, the major reason the Patriot was depoloyed was to face potential assets above that of the Katyusha. Silkworm or similar type threats would be the type for engagement by the Patriots.

I don't think Patriots quit... (Below threshold)
Slartibartfast:

I don't think Patriots quite fit the cruise-missile defense scenario. On the other hand, PAC-3 has that as part of its threat set.

Ah, appears I am behind the... (Below threshold)
Slartibartfast:

Ah, appears I am behind the times. Looks like PAC-2 is either in the process of upgrading capability to counter cruise missiles, or has just finished.

Ariya- Ya I have all th... (Below threshold)
roanoke:

Ariya- Ya I have all the confidence in the Israeli Air Force-I'm just hoping the Syrian Air Force gets eliminated-I hope they are foolish enough-unfortunately it looks like they got the message when President Bush singled them out during "open mike night".


Russell-
The idea that these rockets fly a trajectory too low for Patriot to hit it is total horseshit.

Tell it to the Israelis then. That is the reasoning they are giving. You admt that you are on the developmental end of it and I'll believe the OPERATIONAL guys everytime. The ones that have to BUY it.

Patriot can face cruise mis... (Below threshold)

Patriot can face cruise missiles, but it's not really designed for it. I have no idea what it's success rate would be, but it would probably be considerably less than against typical ballistic missiles. As far as I know, Patriot has never really engaged cruise missiles in the real world (could be wrong).

SLAMRAAM is set to deploy alongside Patriot at some point next year, and it's specifically designed to counter cruise missiles. Some of my coworkers are actively involved in extending our software to work with SLAMRAAM as well as Patriot.

One other thing that very much needs to be pointed out here: the Katyusha rockets that are being fired into Israel are extremely crude weapons. From a tactical standpoint, they have exactly *zero* chance of degrading Israel's military capability, which is another big part of the reason they're being ignored. The casualty rates from these have been extremely low - as near as I can tell, less than one Israeli casualty per rocket. For all the talk of Hezbollah's "sophisticated new weaponry", that's pretty pathetic.

The only value these rockets have at all is as a terror weapon. If they manage to scare the Israeli civilian population enough, it could force a change in Israel's strategic thinking that could benefit Hezbollah.

Frankly, I don't see that happening, certainly not anytime soon. So far, the Israeli's have shown remarkable acceptance of these rockets as something that they just have to bear. They seem to be of the opinion that yes, the rockets suck, but their leadership is going after them at the source - which, as somebody already mentioned, is truly the best, most effecient way to handle the problem.

Frankly, if the civilian population could take it, the simplest way to deal with the threat would be to just wait Hezbollah out and let them fire everything they've got and use up their inventory. I don't think the Israeli political will is strong enough to do that, however - and it probably really shouldn't be, either. They have to respond to these attacks somehow.

The Israeli strategy may not work like they want it to, but it's really the only option they have open.

If you're involved in Patri... (Below threshold)
Slartibartfast:

If you're involved in Patriot, you're probably aware that PAC-3 has hit cruise missiles in flight test.

Probably no RW/non-test intercepts, though, if that's what you're saying.




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