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Subject: The Death of the Warhead?
PowerPointRanger    10/13/2008 12:16:36 PM
We are seeing a new concept in two new missiles intended for missile defense, the SM-3 and the THAAD. These missiles have no warhead in the conventional sense. Instead of an explosive warhead, they use a kinetic hit-to-kill warhead. This does pose certain advantages over the HE warhead. Some warheads can carry 1,000 kg or more of high explosives. And this multiplies dramatically the amount of fuel required to deliver the weapon. This requires that the missile be slow, short-ranged, or very big. Whereas the sensors and electronics of a kinetic HTK warhead are relatively small and light. This means you can get a lot speed and range in a relatively small missile. For example: SM-1ER Warhead: 137lbs Weight: 1,357lbs Range: >46km Speed: Mach 2+ SM-2 Warhead: 137lbs Weight: 1,558lbs Range: >80km Speed:Mach 3+ SM-3 Warhead: HTK Weight: 3,300lbs Range: >247km Speed:Mach 29+ Granted, the weight of the vehicle doubled, but look at what happened to the range and velocity. As for damage, this would certainly destroy any satellite, missile or aircraft it hit. The kinetic energy has been quoted as being 130 megajoules (the equivalent of a 10-ton truck crashing into something at 600mph). While this specific missile would have limited applications in other areas, the concept is certainly a viable one. Suppose, for example, an anti-ship version were made. It could conceivably be enough energy to split a ship in half. Or an anti-tank version? Studies have been done on kinetic-energy tank weapons. While they did not penetrate the armor on an M-1A2 talk, it did kill the tank by creating such a violent impact that it killed the crew, destroyed the electronics and everything mechanical. (Think of it as scrambling an egg without breaking the shell.) Kinetic kill weapons have another benefit: less chance of a catastrophic magazine hit on vehicles that carry them because you don't have HE warheads.
 
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JFKY    Kinteic energy weapons   10/13/2008 1:27:04 PM
have no area effect.  IF you miss with the Hitile you get nothing...hence SAM's have warheads, they only need to get close enough for the proximity fuse to do the damage.  Many of the weapons you cite are in use against NON-Maneuvering satellites or warheads.  Against them, a KE weapon is excellent, but against a maneuvering weapon, not so much, would be my thought.
 
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JFKY    Kinteic energy weapons   10/13/2008 1:29:12 PM
And as to the lessened catastrophic effects of a magazine hit...let several TONS of high energy propellant burn in a magazine, I think you'll be hard pressed to tell the difference between an explosion of warheads and the thermal damage of the propellant burn.  I think it would be a difference that makes no difference.
 
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andyf       10/14/2008 10:30:31 AM
i think i read that if you exceed 4500m/s you deliver more energy than an equivalent mass of HE could
your only problm is thermal heating in the atmosphere
your firing meteors for godsake!
and im thinking endoatmospheric guidance will be dificult
 
 
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doggtag       10/14/2008 11:22:50 AM
You're in the ballpark on that one regarding impact velocities.
 
The thing a lot of people (read as: the generally ill-informed) don't realize about ABM-type interceptions is that,
at such high velocities,
someone explained it to me once that it was along the lines of,
the full masses of the inbound target and the outbound interceptor are actually closing at each other with a velocity faster than both the shockwave of an explosive warhead, and the velocity of the fragments it generates: what good is an explosive whose fragments generally are moving at 1500-3000m/sec or so (depending on explosive type, and shape and density of the fragments) when the combined closing speed of the two missiles (warheads coming in, interceptors going out) can be in excess of several thousand m/sec?
The explosive shockwave, blast heat, and the fragments don't really offer much disruption against such fast-moving targets (by the time the fragment cloud is at its most efficient detonation point and fragment pattern and damage area, the inbound threat could easily then be several hundred, even a few thousand, meters away from that danger area),
whereas hit to kill does just that: a direct impact with the target. Even a glancing blow with that much KE transferred into the target could de-stabilize the target enough to cause it to start tumbling or yawing catastrophically enough that aerodynamic forces and uncontrolled re-entry can do the rest of the destruction.
 
As for using hit-to-kill on aircraft in the lower atmosphere: the HTK interceptor possibly could suffer from greater friction due to the thicker lower atmosphere, causing thermal and even flight control issues (a reaction control system may prove more effective where there is thinner atmosphere and less friction at high altitudes, whereas wings and fins (and aft-mounted TVC nozzles) are better control at lower altitudes),
but at those impact speeds, any given aircraft would have little to no chance of evading,
and that much KE tearing holes thru an airframe would eventually render even the most well-put-together fighter aircraft into useless falling debris (manned airframes just aren't built to withstand that level of kinetic trauma).
 
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Heorot    Hittiles    10/14/2008 12:44:27 PM
are not new. Both Rapier and Sea Wolf were hittiles and were in service 25 years ago
 
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doggtag    Rapier and Seawolf   10/14/2008 2:00:18 PM
Yes but,
each of them actually has some form of explosive (CE- Chemical Energy) warhead, relying not solely on KE impact alone.
 
I don't think it's so much that Rapier and Seawolf were built with the intention of being, principally, hit-to-kill weapons,
but just proof positive of very exceptional British engineering that the guidance and control systems for the weapons are so capable and accurate that actual target impacts by them has become their accepted norm.
( for instance, wasn't it Seawolf, or was it its Seacat predecessor, that supposedly could actually strike 4.5inch naval shells inflight? Still, any ship would have to be on high alert, and its crew routinely trained to do so, to be able to shoot down inbound artillery shells...)
 
Even Starstreak's "little" guided darts (22mm diam, ~16inches long) aren't solely hit-to-kill munitions, as anything I've ever read on them suggests they carry at least some small amount of explosive in each of the three guided darts (Wiki entry suggests a little less than half a kg, about 1 pound's worth, still quite effective when you consider it's actually designed to penetrate into a target vehicle before any of the dart explodes or disintegrates into fragments).
 
For the velocities these missiles operate at (under Mach 4), an explosive warhead and fragment cloud can still generate effective damage to a given target (aircraft and transonic antiship missiles).
 
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WarNerd       10/14/2008 5:54:08 PM

but just proof positive of very exceptional British engineering that the guidance and control systems for the weapons are so capable and accurate that actual target impacts by them has become their accepted norm.

( for instance, wasn't it Seawolf, or was it its Seacat predecessor, that supposedly could actually strike 4.5inch naval shells in flight? Still, any ship would have to be on high alert, and its crew routinely trained to do so, to be able to shoot down inbound artillery shells...)
 
Back in the 1970's International Defense Review reported that the British were using 4.5" naval shells as cheap target drones during the development of the Seawolf anti-missile system, and hitting them more often than not.  However, the system is short ranged and can only protect the vessel that launches it from.  The weight of the system also precluded most vessels from mounting both Seawolf and an anti-aircraft missile system, and the original Seawolf was not accurate enough against crossing targets to be accepted in the anti-aircraft role by itself.  The solution was to add a proximity fuse so that the missile no longer requires a direct hit to function.

Even Starstreak's "little" guided darts (22mm diam, ~16inches long) aren't solely hit-to-kill munitions, as anything I've ever read on them suggests they carry at least some small amount of explosive in each of the three guided darts (Wiki entry suggests a little less than half a kg, about 1 pound's worth, still quite effective when you consider it's actually designed to penetrate into a target vehicle before any of the dart explodes or disintegrates into fragments).

For the velocities these missiles operate at (under Mach 4), an explosive warhead and fragment cloud can still generate effective damage to a given target (aircraft and transonic antiship missiles).


The penetration power of those darts is fairly high, enough to penetrate most IFV's.  Few aircraft have even half that armor, to the explosive charge is to mainly keep the darts from wasting all that energy by punching straight through target aircraft and out the other side.

 
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PowerPointRanger       10/15/2008 2:18:51 AM
I'm not saying it wouldn't be different from the ABM. Obviously Mach 29 is not something you're going to do inside the atmosphere.  However, the principle of a hit-to-kill kinetic round isn't so far fetched.  That's basically what an M-1 uses--except I'm talking about a missile instead of a gun.  The advantages of missiles are already well-documented (beyond visual range, less recoil, etc...).
 
I'm actually talking about the notion of trading off the warhead for extended speed and range.  Is this a practical application in other areas beyond ABM & AA?  What I'm seeing is the application extending into anti-ship, anti-bunker, and possibly anti-tank
 
Indeed, much of the research on the effects of such high-velocity weapons has already been done in the field of electromagnetic weapons, so we know it should work.  The missile is really the only new element in the equation.
 
 
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WarNerd       10/15/2008 2:59:49 AM

Read the full specs on a weapon and understand it's limitations.

The 4th stage homing vehicle on the SM-3 is the  Lightweight Exo-Atmospheric Projectile (LEAP). 

The missile is designed to intercept ballistic missiles head-on in the extreme upper atmosphere or higher.  It is not designed to, and probably cannot, engage targets at normal altitudes, say less than 100,000 ft elevation.  Attempt to engage a target at sea level and atmospheric friction will destroy the missile before it even gets up to speed.

Also, the impact velocity of Mach 29+ is the combined velocity of the LEAP and the target when they hit head-on.  The SM-3 ?only? gets up to around Mach 16. 

 
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WarNerd       10/15/2008 3:52:06 AM

I'm actually talking about the notion of trading off the warhead for extended speed and range.  Is this a practical application in other areas beyond ABM & AA?  What I'm seeing is the application extending into anti-ship, anti-bunker, and possibly anti-tank

Indeed, much of the research on the effects of such high-velocity weapons has already been done in the field of electromagnetic weapons, so we know it should work.  The missile is really the only new element in the equation.

Actually, in most applications you will still have a warhead to optimize target effects, it just may not used conventional explosives.  The LOSAT and CKEM missiles have a tungsten long rod penetrator for a warhead.  It is not explosive, but it is still a warhead the missile has to lug to the target. 
 
Kinetic missiles have  some other disadvantages -- like both a minimum and maximum range.  The missile takes time to get up to the velocity needed for the impact to have the required effect, then it requires a sustainer engine to keep that velocity.  When the sustainer quits the velocity, and the effects on the target, tends to drop rapidly.
 
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