Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!bcm!convex!linac!att!cbnews!cbnews!military From: eachus@aries.mitre.org (Robert I. Eachus) Newsgroups: sci.military Subject: Re: Patriot Question Message-ID: <1991Feb15.071655.11390@cbnews.att.com> Date: 15 Feb 91 07:16:55 GMT References: <1991Feb13.222821.7734@cbnews.att.com> Sender: military@cbnews.att.com (William B. Thacker) Organization: The Mitre Corp., Bedford, MA. Lines: 58 Approved: military@att.att.com Full-Name: News Service 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