Activities of the House Committee on Government Operations
One Hundred Second Congress
First and Second Sessions, 1991 - 1992
Report 102-1086, pages 179- 188
Performance of the Patriot Missile in the Gulf War.
a. Summary.-The Patriot missile system was not the spectacular success in the Persian Gulf War that the American public was led to believe. There is little evidence to prove that the Patriot hit more than a few Scud missiles launched by Iraq during the Gulf War, and there are some doubts about even these engagements. The public and the Congress were misled by definitive statements of success issued by administration and Raytheon representatives during and after the war. It is probable that many of the individuals giving such statements, including the President of the United States and Gen. H. Norman Schwarzkopf, were not aware at the time that the claims of success were false.
American soldiers lives could be unnecessarily endangered if they are deployed in future conflicts based on inaccurate assessments of the Patriot's capabilities. They may depend on Patriot battalions destroying almost all of the enemy missiles, as the Army now claims, when the actual defensive capabilities may mean that it could actually miss almost all of the threatening missiles. Realistic tests are needed to ascertain the true capabilities of this system.
American troops deployed in the Gulf War performed courageously by all accounts. The Patriot crews, in particular, conducted their defensive operations admirably, despite being under the constant threat of chemical and biological attack. The investigation found no fault with the performance of the troops operating the Patriot system. The incorrect initial reports of Scud destruction appear to have been caused primarily by the confusion of war, misleading indicators of success from the Patriot's computer, and the absence of rigorous and systematic ground damage searches in Saudi Arabia.
Official assessments of the number of Scuds destroyed by the Patriot missile system in the war have fallen from
100 percent during the war, to
96 percent in testimony to Congress after the war, to
80 percent,
70 percent and, currently, the Army believes that as many as
52 percent of the Scuds were destroyed overall but it only has high confidence that the Patriot destroyed
25 percent of the Scud warheads it targeted.
Independent review of the evidence in support of the Army claims reveals that, using the Army's own methodology and evidence, a strong case can be made that Patriots hit only
9 percent of the Scud warheads engaged, and there are serious questions about these few hits. It is possible that the Patriots hit more than 9 percent, however, the evidence supporting these claims is even weaker.
The speed of the Scuds, the limitations of the Patriot missile system, and the confusion and targeting difficulties caused by the breakup of the Scud missile as it reentered the atmosphere seem to have contributed to the high failure rate.
The Patriot is not designed to explode upon impact with its target, thus, the explosions in the sky were a misleading indicator of success for both troops and the public. Nor can the system determine if the Patriot missile actually hit its intended target. It can only determine that it detonated near a point in space where it calculated the target should be, sending back a "probable kill" indicator, or that the missile missed and, therefore, detonated to self-destruct.
However, these indicators are inaccurate. Many of the targets turned out to be debris from the poorly designed Scuds as they broke up in flight. At least 45 percent of the 158 Patriots launched in the war were launched against debris or false targets.
Even for those warheads correctly targeted, the Patriot must detonate when it is within a few meters of the Scud to have a high probability of destroying the warhead, according to the Army. However, the Patriot's fuse could detonate at up to six times the required miss distance, resulting in an extremely low or no probability of kill, yet the computer would still record the engagement as a probable kill, according to the Army.
In addition to the probable kill indicator and other tracking data, the Army assessment relies heavily on reports of ground damage. In every case were a warhead kill is claimed, the absence of ground damage is cited as evidence of Patriot success. However, intelligence officials that collected many of these reports from military personnel in the war say that they are unverified, contradictory, erroneous and misleading. Many of the Scuds claimed as warhead kills landed in the desert, the sea or sparsely populated areas.
Finally, some Scuds that were not engaged by Patriots exhibited characteristics identical to those cited as evidence of Patriot interceptions. The Scuds flew in at high speeds, broke up into debris, and upon impact the warheads were found to be duds or only partially burned. In cases where Patriots had attempted to intercept such a Scud, this behavior would be cited as crucial evidence in scoring the engagement as a successful kill.
The Army evaluation of the Patriot's performance was performed by a small team consisting of nine officials from the Patriot Program Office and related Army offices and others from the prime contractor on the program, the Raytheon Co. In addition, as of the April subcommittee hearing, the Army had paid Raytheon $520,000 to provide analysis of Patriot performance in the war. On average, between three and nine Raytheon personnel supported the Army in the post-war performance analysis and approximately 12 Raytheon personnel provided support to the Army in Saudi Arabia and Israel in analyzing Patriot performance and operations.
An oversight hearing was held by the Legislation and National Security Subcommittee on April 7, 1992. Testimony was presented by expert analysts and administration representatives, including:
Steven Hildreth, senior analyst, Congressional Research Service;
Richard Davis, Director, Army Issues, General Accounting Office;
Reuven Pedatzur, Jaffee Center for Strategic Studies, Tel Aviv;
Theodore Postal, Ph.D., Center for International Studies, MIT;
Charles Zraket, former president, MITRE Corp.;
Peter Zimmerman, Center for Strategic and International Studies;
Gen. Jay Garner, U.S. Army accompanied by
Gen. Robert Drolet,
Col. Jim Gustine, Col. David Heebner, Col. Skip Garrett, Chief Warrant Officer Stewart and
Staff Sergeant Lopez; and
James W. Carter, vice president, missile systems division, Raytheon Co., accompanied by
Stephen Stanvick and
Robert Stein.
The subcommittee investigation was conducted with the extensive assistance of nonpartisan analysts from the General Accounting Office, the Congressional Research Service, and the Office of Technology Assessment. Subcommittee investigators conducted extensive interviews with numerous experts as well as officials from the Patriot Program Office in Hunstville, AL and in the Pentagon. Investigators reviewed volumes of classified material concerning the performance of the Patriot missile in the Gulf War.
This material reviewed included:
- Three consecutive versions of the Patriot Program Manager's "Assessment of Patriot Performance in Israel and Saudi Arabia;"
- "Analysis of Damage Caused by Scud Missile Ground Impacts in South West Asia," Ballistics Research Laboratory;
- "Analysis of Video Tapes to Assess Patriot Effectiveness," Army Materiel Test and Evaluation Directorate
- "Summary of SSM Attacks on Israel During Desert Storm," Israeli Air Force;
- "Iraqi SRBM Launch Activity During Desert Storm," Missile and Space Intelligence Center
- "Summary of Patriot-Scud Engagements" Training and Doctrine Command Systems Manager [TSM]
- Experiment 2 digital engagement data
- " Evaluation of the Army Report 'Analysis of Video Tapes to Assess Patriot Effectiveness" Dated 31 March 1992," George N. Lewis and Theodore A. Postol, MIT
- and "Report on 'Patriot Effectiveness,"' Peter D. Zimmerman, CSIS.
Investigators also reviewed over 140 video tapes of media broadcasts provided the subcommittee by the Raytheon Co., and classified Israeli precision and infrared video tapes.
Testimony presented by expert witnesses from the General Accounting Office concluded that the Army's assessment of Patriot effectiveness could not be supported by the data that the Army said it used to arrive at that assessment. GAO specifically concluded that the two principal supporting documents in the Army analysis had serious limitations and did not support the assessment.
A senior analyst from the Congressional Research Service concurred with the GAO testimony and found further that based on the Army's own analysis and methodology,
one Scud warhead may have been destroyed by a Patriot missile. 
Army officials said their original assessment was based primarily on two reports: a classified Ballistic Research Laboratory [BRL] report on Patriot effectiveness; and the Army's classified TSM (Training and Doctrine Command Systems Manager) summary of Patriot-Scud engagements. The General Accounting Office examined both of the primary reports in detail. GAO concluded that these reports simply did not support the Army's stated claims of success. GAO analysts testified:
"The conclusion we reached was that the data the Army used to support their original assessment-that the Patriot's performance in the Gulf was about 70 percent successful-just could not be supported by the data that they said they used to come up with that assessment."
The GAO specifically critiqued the TSM Summary:
"Our review of the principal supporting documents showed the data had serious limitations and did not support the assessment ...."
Our review of the [TSM] spreadsheet and several binders of supporting notes showed that the spreadsheet was actually an inaccurate summary of information obtained through telephone calls to various units in the Gulf, Army staff offices in the Pentagon, or the Patriot Project Office. In addition, many gaps and inconsistencies existed between the data presented on the spreadsheet and the supporting records. For example, there were several instances in which Patriot operators reporteddestroying more Scud warheads than there were missiles launched. In other instances, the supporting telephone record showed the Scud was diverted away from a protected area, but the spreadsheet showed the Scud's warhead was destroyed. In some cases, there were no records supporting the spreadsheet entries."
"The System Manager told us that he was not surprised that we found gaps and inconsistencies in the data. He said the spreadsheet was not intended to be used as an analysis of Patriot's performance. He said it was intended as a tool to keep himself and others at the Air Defense School abreast of events in the Gulf; therefore, he made no attempt to analyze and refine the data."
The GAO also appraised the BRL report and noted several serious limitations:
The report included information on only about one-third of the Saudi engagements, although the Project Manager's assessment cited it as a source for all engagements.
The report assumed that Patriot destroyed Scud warheads in the air unless warhead damage was found on the ground. This assumption is improper because some units did not attempt to locate damage. The report's analysis of identified damage was limited because
(1) it was based on the efforts of one engineer working in Saudi Arabia for 5 days in February 1991 and 19 days in March 1991,
(2) it relied heavily on photographs and interviews with military personnel assigned to the Patriot units, and
(3) site visits were always made days or weeks after an impact when craters had often been filled and missile debris removed.
Congressional Research Service Senior Analyst
Steven Hildreth also criticized the accuracy of the Army report in his testimony before the subcommittee. He concluded:
" Questions can be raised about the thoroughness of the BRL report. In one engagement, for example, the Army uses the BRL report to show there was no ground damage reported. U.S. and Saudi officials. however, re ported finding Scud and Patriot debris in a crater after an attack. In another case, Saudi military officers confirmed damage from a Scud attack, and journalists reported seeing a Scud missile or fuel tank lying in the street. The Army relies on the BRL report to say there was no damage reported."
Reuven Pedatzur, defense affairs analyst with Ha'aretz Daily and the Jaffee Center for International Affairs at Tel Aviv University, testified that Israeli military officers credit the Patriot with hitting only one Scud warhead, with perhaps two others partially damaged:
" During the war a team of Israeli experts, with the participation of representatives from Raytheon and from the U.S. Army, undertook a comprehensive study of the Patriot's intercept attempts.... It was possible to identify those features of the Patriot system which hampered its attempts to intercept the al-Husseins, such as an inability to distinguish between warhead and debris, and the ineffectiveness of its fuse at the high closing speeds which developed between the al-Husseins and the Patriots...."
" During the first day in which the Patriots were operated in Israel, the batteries reported "hits" against the al-Hussein warheads. But in fact the Iraqi missiles were not hit, continued on their route and exploded upon ground impact. Obviously, the reports emanating from the Patriot batteries were at variance with reality...."
" The reports of successful hits received from the Patriot batteries were found to derive only from the fact that the Patriot warheads were activated precisely where and when intended...."
The video recordings showed clearly that the Patriots were not hitting the Iraqi missiles' warheads, in some cases they were missing by hundreds of meters.
A panel of expert witnesses disagreed over the reliability of video footage of Patriot engagements that seemed to show Patriots consistently missing the Scuds at which they were aimed. Dr. Theodore Postol of MIT explained:
"The Patriot can be thought of as a platform which carries a shotgun that sprays pellets at the target it is to destroy ... if the Patriot fires its pellets at a range much greater than 5 to 10 meters from its target, it will be increasingly unlikely that even one pellet will hit the target. Thus, a 30 meter miss distance is nine times less likely to damage the target than a 10 meter miss and a 100 meter miss is 100 times less likely to damage the target. "
"This means that if miss distances much larger than 100 meters are observed, the result will be a near zero probability that even one pellet from the interceptor will have hit the target."
Dr. Postol contended that his analysis of video tapes of roughly 25 Patriot intercept attempts showed "all but 2 to 4 intercept attempts are hundreds of meters or more."
Dr.
Peter Zimmerman and Dr.
Charles Zraket disagreed. They presented charts and video tapes prepared by the Raytheon Co. to argue that in the 1/30 of second it takes to go from one still frame of a video tape to the next, the Scud would travel 35 meters at full speed. Thus, Dr. Zimmerman said:
"Video images will always show a late detonation; it is in the nature of the recording process. Television will always show the Patriot detonating behind the Scud. As a result, videotape will nearly always mislead the unwary analyst into perceiving a clean intercept as a miss with the Patriot warhead detonating too late, behind the Scud warhead which is its target. "
Dr. Zraket asserted that the ground damage studies "would provide the most valid indirect method of assessing results." He testified:
"Simple calculations indicate that the 500 to 600 pounds of high explosive in the Scud warhead would be sufficient ... to demolish virtually all types of residential and much commercial construction. When Scuds explode in populated areas such devastation is unmistakable, and the lack of such devastation associated with the identified impact of a Scud warhead is conclusive evidence that the warhead did not explode upon impact ...."
" There is a common sense argument that ... if you don't have a lot of catastrophic damage in an area say in Israel or in eastern Saudi Arabia, when something like over 30 Scuds fell in each of the inhabited areas and almost 50 were fired into each area, then common sense tells you that something is going on that is preventing that Catastrophic damage."
General Garner testified that since the subcommittee staff investigation began the Army officials responsible for the analysis had redone their evaluation. The new analysis was presented in general terms to the subcommittee at the hearing. The supporting documents were provided to the subcommittee after the hearing. The revised Army analysis would no longer rely on the two reports that had been the foundation of their original appraisal. The Army would no longer rely on the TSM report and would supplement the BRL report with other ground damage information. The Army also testified that as a result of its new analysis, it had adjusted the claims of Patriot success. The new analysis concluded:
The Patriot had delivered "a miracle performance."
The Army knows the Patriot was operationally successful, but did not have scientific proof of that success.
The data collection effort was the best the Army could do; it was a war, not a test range.
The Army's new effectiveness assessment was that the Patriot had hit, though not necessarily destroyed, 40 percent of the Scuds it engaged in Israel and 70 percent in Saudi Arabia.
Of the Scuds intercepted, the Army had high confidence the Patriot had destroyed 25 percent of the warheads.
Examination of the new analysis indicates that although improved in clarity and format, the revised assessment continues to suffer from many of the same deficiencies as the original assessment. The Army assessment does not support the overall effectiveness claim or the specific claims of the Scud warheads destroyed. The strongest evidence in the Army assessment indicates that the 158 Patriots fired during the war destroyed a few Scud warheads, although there are doubts about these.
Hearing.-"Oversight Hearing on the Performance of the Patriot Missile- in the Gulf War," April 7, 1992.
