Video evidence on the effectiveness of patriot during the 1991 gulf war

Notes and references

• Conyers , John Jr. 1992 . “The Patriot Myth: Caveat Emptor,” . Arms Control Today , November : 3 – 10 .
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• Schmidt , Eric . 1992 . “Israel Plays Down Effectiveness of Patriot Missile,” . New York Times (International Edition) , 19 October : A8
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• Bronner , Ethan and Farrell , John Aloysius . 1992 . “US, Israeli Experts Dispute Patriot Claims,” . Boston Globe , 19 March : 1
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• If we assume a total of 46 engagements, then the Army's claimed success rates lead to the following:
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• Since the Army claims that 52% of the engagements were warhead kills:
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• The above calculations lead to the conclusion that in three engagements claimed as successes, Patriots diverted Scuds off their trajectory and out of the defended area without destroying the Scud warheads or caused the Scud warhead to detonate with less than full yield (such a result was termed a “mission kill").
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• US General Accounting Office . September 1992 . Operation Desert Storm: Data Does Not Exist to Conclusively Say How Well Patriot Performed , GAO/NSIAD‐92–340 September , 3 However, the Army's classification of an engagement as a high confidence warhead kill is misleading. The assignment of a high confidence warhead kill to a particular engagement only means that the Army has higher confidence of a warhead kill relative to other engagements in which the Army believes there is some evidence of success. The GAO review of the Army's claims reports that, “According to the Deputy Project Manager, the assignment of a high confidence level to an engagement's outcome did not mean that the Army was absolutely confident that the assessed outcome was correct. Rather, given the limited data available for assessment purposes, the Army scorers had higher confidence in the assessed outcome of these engagements than in others.”
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• US General Accounting Office . 7 April 1992 . Operation Desert Storm: Project Manager's Assessment of Patriot Missile's Overall Performance is Not Supported 7 April , GAO/T‐NSIAD‐92–27,
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• Hildreth , Steven A. 7 April 1992 . “ (Congressional Research Service) ” . In Evaluation of US Army Assessment of Patriot Antitactical Missile Effectiveness in the War Against Iraq , 7 April , Testimony prepared for the House Government Operations Subcommittee on Legislation and National Security .
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• National Security Subcommittee of the House Government Operations Committee . 1993 . Performance of the Patriot Missile in the Gulf War , Washington D.C. : US Government Printing Office . and US General Accounting Office, Operation Desert Storm: Data Does Not Exist. All of the above reports are reprinted in Hearing before the Legislation and
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• Army Material Test and Evaluation Directorate, White Sands Missile Range . 1992 . Analysis of Video Tapes to Assess Patriot Effectiveness (Rev 1) , 31 March A US Army report concluded that the news media videos were not useful in determining whether a Patriot hit or missed a Scud.
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• There are also a small number of videos from Haifa, Israel. However, we have seen no videos from the other major Scud target, the large military complex at King Khalid Military City in Saudi Arabia.
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• An entire engagement, from the launch of the first Patriot interceptor to the impact of the Scud warhead on the ground, typically lasts about 25 seconds. Broadcast video is generally cut to show only what the news media judges to be the most interesting parts of the engagement, such as Patriot launches, the detonation of Patriot warheads, or Scud explosions on the ground. Unedited video typically allows a much more complete reconstruction of events. The videotapes provided to us by ABC and WETA‐TV contained both edited and unedited footage.
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• Lewis , George N. and Postol , Theodore A. September 1992 . An Evaluation of the Army Report “Analysis of Video Tapes to Assess Patriot Effectiveness,” Dated 31 March 1992: A Study Performed in Response to a Request by Congressman John Conyers, Jr., Chairman of the House Government Operations Committee , September , Cambridge, Massachusetts : M.I.T. Defense and Arms Control Studies Program .
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• Lovece , Joseph . 1992 . “Electronic Noise From US Gear Prompted Errant Patriots,” . Defense Week , 28 September : 1 Although 158 Patriots were fired during the Gulf War, approximately 24 were launched accidentally ("were launched at empty airspace") while about another 47 were fired at Scud debris. Thus only about 87 Patriots were actually fired at Scud targets.
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• The US Army did not use video cameras to record any of the Patriot engagements. Further, digital data recorders were used in only three of the roughly 47 engagements. The Israelis did, however, set up high‐resolution test‐range video cameras near Tel Aviv and recorded a number of engagements there (although many of the engagements near Tel Aviv took place in cloudy conditions).
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• One of the videos (containing two intercept attempts on one Scud) is almost certainly not from the news media: it appears to have been taken with an infrared camera. At present we do not know the source of this video, although it is known that the Israelis did record some engagements using infrared cameras. The infrared video was broadcast on the program “Admiral William J. Crowe: The Lessons of Modern War,” broadcast on the Boston PBS station WGBX at 11 PM on 10 January 1993.
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• Lewis and Postol . “An Evaluation of the Army Report,” . 63 – 65 .
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• For example, such arguments against the use of the news media video tapes have been made by analysts at the White Sands Missile Range (where miss distances can be determined to within 0.3 meters). Army Material Test and Evaluation Directorate, “Analysis of Video Tapes.”
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• Each video frame is captured as a digital picture that is 512 pixels wide and 480 pixels high. The color information associated with each digitized pixel is stored as a 24 bit number, which can potentially represent 16.7 million colors or shades of gray. Although only eight bit (256 color) data was used for the pictures in this article, the full 24 bit raw data from the video board is readily captured and stored as digitized images with our current system.
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• Thus frames 10g, 11g, and 11h use different settings than the other frames of the Video Sequences in which they are contained. In addition, frames 5a through 5d use different settings than 5e through 5h (which were taken by a different camera).
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• This video clip was provided to us by WETA‐TV in Washington DC.
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• Postol , Theodore A. 1991/92 . “Lessons of the Gulf War Experience with Patriot,” . International Security , 16 ( 3 ) Winter : 119 – 171 . For background information on the Patriot system and the Scud targets, see
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• The assumptions used in calculating the Scud trajectories used in this paper are described in appendix B. The Patriot trajectory shown in figure 1 is calculated by assuming that the Patriot first flies up nearly vertically and then attempts to fly up the Scud's expected trajectory.
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• It appears that the Patriot detonation actually began just as the video camera's shutter was closing for this frame. This is indicated by a diffuse patch of light alongside the Scud's wake; this patch is in the same location as the Patriot fireball in the next frame.
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• US General Accounting Office . Operation Desert Storm: Data Does Not Exist 6 The GAO also reported (p. 7) that, “[The Patriot Project Office] Chief Engineer said that Patriot's fuze can sense its target and detonate at up to six times the required miss distance, resulting in an extremely low or no probability of kill. However, the system would still record a kill.”
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• Because the available data does not allow a precise determination of the fireball diameter (and because it is also likely that the observed fireball diameters may vary depending on factors such as intercept altitude and camera settings), we do not use the fireball diameter as a length scale in determining hits and misses or in measuring miss distances. In addition, in some of the brighter Patriot fireballs observed in the videos, where there is a considerable amount of light scattering around the fireball, the apparent size of the fireballs are strongly dependent on the brightness and contrast settings of the television (especially in the first few frames after the warhead detonation). See frames 5d and 6b of this paper, which show the same video frame with different brightness and contrast settings, and between which there is a factor of two or more difference in the fireball diameters. (However, the Patriot fireballs in the engagement we are now discussing do not appear unusually bright and their size is not dependent on the television settings.)
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• A simple way to roughly analyze this engagement is to assume that the Scud's trajectory is a straight line passing through the center of the fireball (this assumption will lead to only a small error in this case). For example, first measure the apparent miss distance (the distance between the center of the fireball and the Scud) on frame 1c— about 6 millimeters. Then measure this same distance in frame 1f (nine frames later)—about 12 millimeters. Thus the Scud moved about 6 millimeters in nine frames. Thus the video uncertainty is about 0.7 millimeters and the miss distance is about 6/0.7 = 9 times the video uncertainty.
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• In cases where we observe clear misses, it is apparent, given the large size of miss distances, that the Patriots could not have fuzed on the actual Scud targets. Indeed, it seems likely that many of the clear misses we see involve the Patriot self‐destructing after failing to fuze on the Scud target. Since the Patriot generally attempts to intercept the Scud head‐on (that is, the Patriot is flying the Scud's trajectory in reverse), this self‐destruct would be expected to occur in or near the Scud's wake. Alternatively, some of the clear misses might involve the interception of debris trailing behind the Scud, in which case the Patriot detonation would also be expected to occur in or near the Scud's wake.
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• US General Accounting Office . Operation Desert Storm: Data Does Not Exist 6 When an engagement failed, the Patriot missile was commanded to self‐destruct after a pre‐set time delay.
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• Zimmerman , Peter D. 14 September 1992 . Report for the House Government Operations Legislation and National Security Subcommittee on “Patriot Effectiveness (Rev 1)” and Other Related Subjects Concerning Patriot ATBM Performance During Operation Desert Storm 14 September , Army Material Test and Evaluation Directorate, Analysis of Video Tapes;
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• House Government Operations Committee . Performance of the Patriot Missile 328 – 341 . See also affidavits by Lawrence S. Silverman and Kerns H. Powers, which are reprinted in
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• House Government Operations Committee . Performance of the Patriot Missile 309 – 327 . Letter from James W. Carter (Vice President, Raytheon Company) to US Representative John Conyers, Jr., Chairman of the House Committee on Government Operations, 14 August 1992, p. 11. This letter is reprinted in
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• Zimmerman , Peter . Report for the House 13
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• Postol . “Lessons of the Gulf,” . 126 – 130 .
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• As far as can be determined from publicly available information, most or all of the Scuds fired by Iraq during the Gulf War, whether engaged by Patriot or not, broke up on re‐entry. The persistent and incandescent wake trailing behind many of the Scuds strongly suggests that debris was coming off the Scuds throughout much of the time they were in the atmosphere. Thus it may be more accurate to think of the Scuds as undergoing a series of breakups, with the breakup such as the one illustrated in Video Sequence 2 being the “main” breakup (the one in which the warhead section separates from the Scud missile body).
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• The ground explosion and fireball were also observed by another camera at a different location. However, cases such as this where the camera is relatively close to the impact point and has a clear line of sight to the impact point are relatively rare. The only other such case we have seen is the Scud that landed on or near the airbase at Dhahran on 23 January (there are also two additional video clips in which the Dhahran 23 January explosion is seen as a flash occurring behind nearby buildings). In most cases, the explosion of the Scud warhead is seen only as a flash on or over the horizon.
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• Although it may appear that a well‐defined fireball is visible in frames 4e and 4f, when the video is viewed on a color television, it is apparent that much of the apparent fireball diameter in these frames is actually due to scattered light. As we will see below, this fireball is far too large to be a true fireball (a ball of hot radiating gas). The exact nature of what is seen here (and when a Patriot warhead detonates) is unclear, but undoubtedly involves complex physical phenomena.
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• These dimensions can be established by noting that the width of the fireball in 4g is somewhat greater than the distance the Scud moves in the six video frames between 4a and 4b (this must be measured with respect to stationary ground features, because the camera is moving). The speed of the Scud at impact is not known precisely, but a figure of 700 m sec‐1 is reasonable (this is the impact speed for the trajectory shown on figure 1 and discussed in appendix B—an intact Scud would hit the ground at about 1.5 km sec‐1). The warhead will hit the ground at an angle from the vertical of about 48°, so sin a is at least 0.74. Thus the camera sees the Scud moving at 0.70 • 0.74 = 0.52 km sec‐1 = 17 meters per frame, for a total of roughly 100 meters between 4a and 4b.
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• Due primarily to the inaccuracy of the Scuds, only a relatively small fraction of the Scuds (less than one in four) are reported to have caused casualties or significant ground damage. Despite this, the video record contains a number of cases where a flash from a ground explosion is seen and for which it is known that the Scud that produced this flash caused casualties or significant damage. In Tel Aviv, such cases are two Scuds on 25 January, a Scud on 9 February, and a Scud on 12 February. In Riyadh, these cases include the second Scud on 25 January, and single Scuds on 3 and 11 February. In Dhahran, the explosion of the Scud that destroyed the US military barracks on 25 February is also on the videos. These cases provide clear examples of what distant Scud warhead explosions look like.
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• Horton , Frank . 1993 . “The Patriot Debate: Part 2,” . Arms Control Today , January/February : 26 – 29 . Former US Representative Frank Horton (who was the ranking minority member on the House Government Operations Committee during that Committee's investigation into the performance of Patriot) recently stated, apparently based on the classified US Army assessment, that this engagement was successful.
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• All three of the camera views of this intercept attempt are from the tape provided to us by ABC.
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• The third view of this intercept attempt is very similar to the second view described below, and possibly was filmed from the same location.
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• The Patriot's rocket motor burns for about 12 seconds. The only other intercept attempt we have seen where the Patriot's motor was still burning (or had just burnt out) when the Patriot warhead exploded was the fourth intercept attempt on the Scud at Tel Aviv on 11 February (see Video Sequence 13).
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• Both of the other cameras show an identical sequence of events.
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• Frame 6a is the same as frame 5c, but with different brightness and contrast settings.
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• It might be expected that the fireball produced by the detonation of a Scud warhead would be considerably larger than that produced by a Patriot warhead detonation, since the Scud warhead contains several times more high explosive (roughly 200 kilograms) than does the Patriot (roughly 40 kilograms). However, given the wide variation in apparent Patriot fireball diameters seen on the videos, it is not clear that this difference would be discernible.
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• The argument has also been raised that a Scud could be hit by one or a few Patriot warhead fragments that do not detonate the Scud's warhead but result in the Scud's warhead not detonating when it strikes the ground. However, to our knowledge, no one has proposed a mechanism which could produce such a result except as a relatively low probability and thus infrequent event.
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• However, in such cases there is normally a very small bright core to the fireball in the first frame that is surrounded by an area of scattered light. The flaring of the Scud here does not have that appearance.
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• Such debris clouds are readily visible in the press videos. They are typically produced during a time interval of tenths of seconds as a Scud breaks up, and once created they remain visible in the press videos for seconds.
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• This engagement is catalogued as tape VMS‐8 at 33:14 in Army Material Test and Evaluation Directorate, Analysis of Video Tapes, Appendix A.
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• In addition, this intercept attempt occurs at a low altitude (less than fuve kilometers). Thus the main Scud breakup, which typically occurs at or above an altitude of ten kilometers, should have already occurred. However, little is known about what happens in such breakups and it is possible that there is enough of the Scud remaining with the warhead section to produce a second large breakup debris cloud.
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• The shoulder‐carried camera has been moving towards the street light seen in Video Sequence 8 (the same one seen in frames 5e to 5h), and the large round light seen at the bottom of frames 5e to 5h is now just behind the camera.
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• Such a long‐lasting debris pattern is not seen following Patriot detonations that occur after the Patriot's solid rocket motor has burned out (which is what normally occurs). However, the debris pattern is similar in appearance to that seen when Patriots detonate prematurely after only a few seconds of flight.
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• The videos we have analyzed show eight ground explosions in or near Riyadh—seven due to Scuds and one due to a Patriot that dove into the ground. Three of the seven observed Scud detonations produced reports of casualties and damage to buildings, three did not, and one probably did not. The only other reported instance of casualties and damage in Riyadh probably resulted from a Patriot that dove into the ground.
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• This description is based on reporting from the impact scene and video of the impact scene and damaged building that was broadcast on CNN and ABC.
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• Private communication from Reuven Pedatzur.
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• Government Operations Committee . Performance of the Patriot Missile 277 – 308 . Letter from Major General Jay M. Garner, US Army, to Representative John Conyers, Jr., Chairman of the House Government Operations Committee, p. 10. This letter is reprinted in
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• Conyers , John Jr. 1993 . “The Patriot Debate: Part 2,” . Arms Control Today , January/February : 27 29 According to the Chairman of the House Government Operations Committee, “In the Army assessment, a dud Scud scored as a warhead kill if a Patriot had attempted an intercept. However, many of the Scuds were duds to begin with. Scuds were found with concrete warheads, or little explosive, or broken wires in the fuzing section. Several of these were scored as kills, even without corroborating evidence such as radar data. The duds were often burned and broken from impact, but this was hardly “clear physical evidence of Patriot intercept damage,” although in one case an Army officer thought a Patriot fragment caused a hole. This opinion was not supported by any chemical or metallurgical analysis or recovery of a fragment. Duds not engaged by Patriot showed similar damage.”
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• Lewis , George N. , Fetter , Steve and Gronlund , Lisbeth . March 1993 . Casualties and Damage from Scud Attacks in the 1991 Gulf War , Working Paper 93–2 March , 29 Defense and Arms Control Studies Program, M.I.T. . On 19 January, before Patriot was operational in Israel, a Scud warhead struck a multi‐story building in downtown Tel Aviv. The warhead was recovered intact from a ground floor jewelry store. See
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• It is unclear why some fireballs appear to be unusually large and bright on the videos. Brighter fireballs might be due to detonations that occurred relatively close to the camera or to variations in video camera settings.
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• There are at least two reasons for the very large ratio of fireball diameter to apparent Scud motion per frame in this intercept attempt. First, as discussed above, the apparent fireball diameter as seen on the video may be larger (by a factor of about two) than the “true” fireball because, in the frames shortly after the detonation, there is a great deal of light scattering in the air around the fireball which makes the actual extent of the fireball difficult to measure. Second, this Scud landed relatively close to the camera—about 2.25 kilometers away. Thus when the Scud is first acquired by the camera, its angular position will change relatively slowly.
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• The two video clips follow immediately one after the other on the videotape provided to us by ABC. However, it is also possible that the second clip was taken by the third camera. Following the intercept attempt on the first Scud, the clip from the third camera is cut. It is immediately followed by two short video clips, the first one showing a Scud rapidly streaking across the sky, and the second one is a repeat of the video clip from which Video Sequence 10 was taken. In either case, as we will see, the camera was at the Marriott.
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• This clip was broadcast on NBC Nightly News, 25 January 1991.
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• Browne , Malcolm W. “2 Office Buildings Leveled in Riyadh; Body Recovered,” . New York Times (International Edition) , 26 January : 16
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• Owen , Richard and Walker , Christopher . 1991 . “Two Killed and 70 Hurt in New Scud Onslaught,” . London Times , 26 January : 1e (One of the deaths and many of the injuries cited in the title of the London Times article occurred in attacks on Israel on the same night.)
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• Owen and Walker, “Two Killed and 70 Hurt.”
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• The commander of the US Patriot forces in Israel testified that: “We deployed with software version 33, which we had confidence in, but a lot of unknowns about because it was brand new to us.
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• “Now, within three days [the first Patriot engagement in Israel was on 22 January —three days later is 25 January] we found out it was flawed. It was flawed not simply because it wasn't engineered well. It was engineered against a different kind of threat. And if I can put it into context, in the United States, we were trained and the system was designed against a system that pitched a fast ball. What we got was a system that threw a knuckle ball. It was not a simple process to understand exactly what was happening.
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• Testimony of Colonel David Heebner, House Government Operations Committee . Performance of the Patriot Missile 234 “But we within a few days—the soldiers who represented the United States of America and Israel made changes to that system based on their own ingenuity that caused us to stop the problems we experienced on 25 January.”
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• Starting on 26 January, the Patriot batteries in Israel switched from operating in automatic mode to operating in semiautomatic mode. This change allowed Patriot to attempt to intercept only the fastest falling object to emerge from the Scud breakup— the Scud warhead section.
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• Two Patriots are seen on the videos diving into the ground in Saudi Arabia and three in Israel. There are several other instances on the videos of Patriots diving into the ground, however, we believe that these are likely to be different camera views of the five Patriots cited above.
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• House Government Operations Committee . Performance of the Patriot Missile 279 Representative John Conyers, Jr., Chairman of the House Government Operations Committee, submitted the following written question to the US Army: “There are reports of eight PATRIOTS hitting the ground in Israel alone, are these reports correct?” The Army's response is classified.
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• The Patriot that dove into the ground in Haifa followed a similar, although perhaps somewhat higher, trajectory. However the other three Patriots seen diving into the ground followed significantly different trajectories. Each of these three Patriots was heading upwards until it abruptly made a sharp turn and dove into the ground. This behavior may reflect some other problem with the Patriot system.
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• All four intercept attempts on this Scud were clear misses. It is not known why four Patriots, all from the same battery, were fired at this Scud.
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• We believe that all of the 33 intercept attempts are unique events, but we cannot absolutely rule out that two of them (one clear miss and one fireball overlap), contained in two engagements, could be different views of other intercept attempts already evaluated. (In appendix A, these two engagements are listed as the third Scud at Dhahran on 20/21 January and the first “date‐and‐place‐unknown” event).
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• There were three engagements containing fireball overlaps in which no ground explosion was seen on the videos. In one of these cases (in appendix A, this is listed as the third Scud at Riyadh on 21 January), the Scud did not appear to be affected by the intercept attempt, but the camera did not track the Scud to the ground. In another case, (the third Scud at Dhahran, 20/21 January) the Scud again did not appear to be affected by the explosion, but was tracked most or all of the way to the ground and no explosion was seen. However, this Scud appeared to have landed at a large distance from the camera, and it is possible the flash of a ground explosion was not seen for this reason. (Another Scud that appeared to land quite far from the camera (Tel Aviv, 12 January) had a ground flash that was only faintly visible). Moreover, some Scuds that were not engaged by Patriot are also known to be duds. The third Scud was the one to Tel Aviv on 19 February; it is discussed in the text. See also the discussion in note 52.
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• See the sources cited in note 4.
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