rdz@dec-lite.stanford.edu (Ramin Zabih) (02/14/91)
From: rdz@dec-lite.stanford.edu (Ramin Zabih) It seems that the Patriot's major shortcoming is that when it intercepts a SCUD, the SCUD can still do significant damage. I was wondering whether this shortcoming is a result of the Patriot being originally designed for anti-aircraft, rather than anti-missile, defense. For instance, the size of the explosive charge necessary to knock out a hostile airplane is presumably smaller than that for a missile. Also, it seems to me that an anti-missile missile would want to hit the target directly, while an anti-aircraft missile might be programmed to explode nearby the target. Does anyone know if these factors are responsible for the occasional SCUD damage? How hard would it be to increase the warhead size, or to program it to achieve a direct hit? -- Ramin Zabih Computer Science Department rdz@Gang-of-Four.Stanford.EDU Stanford University
tb2@doc.ic.ac.uk (Timothy Brown) (02/15/91)
From: Timothy Brown <tb2@doc.ic.ac.uk> In article <1991Feb13.222821.7734@cbnews.att.com> rdz@dec-lite.stanford.edu (Ramin Zabih) writes: >From: rdz@dec-lite.stanford.edu (Ramin Zabih) >... I was wondering whether >this shortcoming is a result of the Patriot being originally designed for >anti-aircraft, rather than anti-missile, defense. >[Various comments on the difference between anti-aircraft and anti-missile > missiles]. Another thing to remember is that one doesn't have to destroy a plane entirely, since the planes weapons are not so much for inflicting heavy but random damage on its target like the SCUD, rather for localised (but strategic) damage. If an aircraft is shot down odds are that it and its payload will fall on someones house rather than your nuclear power station, a sad but more acceptable situation. The plane just has to fall out of the sky to be (relatively) harmless. A SCUD will fall out of the sky anyway, and cause damage unless it completely misses the city. Instead of reprogramming/rearming the Patriot, it would probably be a better idea to redesign the whole thing. They'd make a better job of it that way. -- ,------------------------------------------------------------------------^^ | HUMPTY DUMPTY WAS PUSHED... BUT BRITISH JUSTICE CONVICTED THE WRONG |oo| | MEN. FREE THE HUMPTY DUMPTY 6! (or mailed flames sorry) \v / '-Sorry, can't respond to international E-mail^(YET)---tb2@doc.ic.ac.uk--mm
dnwiebe@cis.ohio-state.edu (Dan N Wiebe) (02/15/91)
From: dnwiebe@cis.ohio-state.edu (Dan N Wiebe) Ramin Zabih writes: >Does anyone know if these factors are responsible for the occasional SCUD >damage? How hard would it be to increase the warhead size, or to program >it to achieve a direct hit? Well, I've got no access to classified information, but it seems to me that the problem is one of physics rather than software or (Patriot) warhead size. The successful Patriot detonates at or near the incoming Scud warhead, hopefully screwing up the fuzing system and maybe even blowing the thing into a bunch of separate chunks. But you've still got a ton or so total of incoming missile that's been falling for 60 miles or so and has a fair amount of kinetic energy--and since its path is completely ballistic, having a Patriot create a nearby explosion is not going to deflect it appreciably from its established path. It's going to come pretty much right on in, and when it hits, it'll make a fair-sized hole--or several of them. Also, the heat generated by the impact might be enough to set off whatever explosive hasn't blown yet--and there will probably be some, since from what I hear it's quite difficult to set off a bomb with a well-designed fuzing system without satisfying the fuzing parameters. That is, if a bomb is fuzed to go off when it hits the ground, a good WHAP from a nearby explosion probably isn't going to make it go off early. However, I'd estimate that the heat of impact after 60 miles of fall would be enough to set off just about any chemical explosive, regardless of the fuzing system. What do the rest of you think? Dan Wiebe dnw@rsch.oclc.org
ins_atge@jhunix.HCF.JHU.EDU (Thomas G Edwards) (02/15/91)
From: ins_atge@jhunix.HCF.JHU.EDU (Thomas G Edwards) In article <1991Feb13.222821.7734@cbnews.att.com> rdz@dec-lite.stanford.edu (Ramin Zabih) writes: > > >From: rdz@dec-lite.stanford.edu (Ramin Zabih) >It seems that the Patriot's major shortcoming is that when it intercepts a >SCUD, the SCUD can still do significant damage. The intercepted SCUD can still do significant civilian damage, but its ability to significant military damage (i.e. against runways or hardened bunkers) is drastically reduced. Intercepted missiles will also fall far away from their target point. This doesn't make a lot of difference to a SCUD, but for a well-guided missile this could be the difference between hitting the intended target and missing it totally. Also, so far the SCUDs have had conventional warheads. A chemical, biological, or nuclear warhead would amplify the difference between interception and non-interception. >For instance, the size >of the explosive charge necessary to knock out a hostile airplane is >presumably smaller than that for a missile. The larger the explosive warhead, the more difficult it is to accelerate and manoeuver the missile towards the incommming missile. The main objective of the Patriot is to try to make the missile fall at a non-target location, and also to try to disable the warhead. It is impractical to have a large enough change to reduce the incomming missile to little grains of metal. Of course, nuclear warheads on anti-missile systems would be able to do that, but they have nasty associated radiation properties. But it is often preferable to have a small nuclear blast at altitude than a larger blast at ground level. -Thomas Edwards
eachus@aries.mitre.org (Robert I. Eachus) (02/15/91)
From: eachus@aries.mitre.org (Robert I. Eachus)
In article <1991Feb13.222821.7734@cbnews.att.com> rdz@dec-lite.stanford.edu (Ramin Zabih) writes:
It seems that the Patriot's major shortcoming is that when it intercepts a
SCUD, the SCUD can still do significant damage...
We were discussing at lunch the fact that the Patriot missiles
are doing better! than expected at minimizing damage from a Scud with
a conventional warhead... Think of it like this: There is a 2000 lb.
(or 1000 Kg. if you prefer) coming at you at about 2000+ mph (3000+
kph.). Your nice Patriot defence system hits it head on (best case)
with say 500 lbs. at 1000 mph. Even if the collision causes the
oncoming missile to explode, that still leaves a lot of metal coming
at you real fast...
This is why, if the Patriot's radar system shows the missile is
headed towards open ground, no attempt is made to intercept. It will
almost certainly hit somewhere, and if you like the current somewhere,
don't muck with it.
Again, approximate numbers, because we are really talking about
several different versions of different missiles, different
trajectories, etc. But imagine that the incoming missile is not
intercepted. The amout of damage done will be somewhere between a
2000 lb. bomb and a 16" Battleship round, possibly more. Interception
and destruction of the explosive charge in the warhead, but leaving
the Scud basically intact, can get this down to about a 6" round or a
250 lb. bomb, maybe smaller. Lots of interceptions are in this class.
You see the missile spinning to the ground, spitting fire out of the
ruptured warhead. (The tumbling rubs off speed, and at this point the
missile is nothing but a kinetic projectile.)
If the Scud warhead went off early, there might be very little
high-speed debris hitting the ground, but one hell of a sonic boom,
breaking windows over a wide area. The expanding gases from the
explosion would be trapped by the missile's shock wave, and all the
forward energy from the explosion would be tranferred to the sonic
boom. However, if you have seen the television pictures of
interceptions that look like starburst shells, this doesn't happen
when the Patriot causes the explosion. Apparently the Patriot's shock
wave disrupts the Scud's shock wave enough that the explosion is not
confined and you get pretty fireworks.
It is hard to explain to technically unsophisticated people, that
the thing that hit in the middle of the street with a big boom did
not, in fact, explode, that the boom that broke windows and knocked
down houses was a sonic shock wave, and that the big hole was caused
"merely" by kinetic energy from falling debris...
--
Robert I. Eachus
Our troops will have the best possible support in the entire
world. And they will not be asked to fight with one hand tied behind
their back. President George Bush, January 16, 1991