Editing MIM-104 Patriot (section)

===Persian Gulf War (1991)===

====Trial by fire====
Prior to [[Gulf War|the First Gulf War]], ballistic missile defense was an unproven concept in war. During Operation Desert Storm, in addition to its anti-aircraft mission, the Patriot was assigned to shoot down incoming Iraqi [[Scud]] or [[Al Hussein (missile)|Al Hussein]] short range ballistic missiles launched at Israel and [[Saudi Arabia]]. The first combat use of Patriot occurred January 18, 1991, when it engaged what was later found to be a computer glitch.<ref name="DACS Working Paper">{{cite web |url=http://kms1.isn.ethz.ch:80/serviceengine/Files/ISN/19691/ipublicationdocument_singledocument/600a9352-1c22-46c3-870d-f60dc987403e/en/Casualties_Scud_Attacks.pdf |first1=George N. |last1=Lewis |first2=Steve |last2=Fetter |first3=Lisbeth |last3=Gronlund|author3-link= Lisbeth Gronlund |title=Casualties and Damage from Scud Attacks in the 1991 Gulf War |date=March 1993 |website=Massachusetts Institute of Technology Defense and Arms Control Studies Program |access-date=May 11, 2010 |archive-url=https://web.archive.org/web/20160102043600/http://kms1.isn.ethz.ch/serviceengine/Files/ISN/19691/ipublicationdocument_singledocument/600a9352-1c22-46c3-870d-f60dc987403e/en/Casualties_Scud_Attacks.pdf |archive-date=January 2, 2016 |url-status=dead}}</ref> There were actually no Scuds fired at Saudi Arabia on January 18.<ref name="United Kingdom Ministry of Defence">{{cite web |url=http://www.gulflink.osd.mil/al_jub_ii/al_jub_ii_refs/n50en122/british_mod.htm |title=A Review of the Suggested Exposure of UK Forces to Chemical Warfare Agents in Al Jubayl During the Gulf Conflict |date=January 2000 |website=Office of the Special Assistant for the Gulf War Illnesses |access-date=May 11, 2010 |archive-url=https://web.archive.org/web/20101110095650/http://www.gulflink.osd.mil/al_jub_ii/al_jub_ii_refs/n50en122/british_mod.htm |archive-date=November 10, 2010 |url-status=dead }}</ref> This incident was widely misreported as the first successful interception of an enemy ballistic missile in history.

Throughout the war, Patriot missiles attempted engagement of over 40 hostile ballistic missiles. The success of these engagements, and in particular how many of them were real targets, is still controversial. Postwar video analysis of presumed interceptions by [[Massachusetts Institute of Technology]] (MIT) professor [[Theodore Postol]] suggests that no Scud was actually hit.<ref name="fas_starwars">{{cite web |url=http://www.fas.org/spp/starwars/congress/1992_h/ |title=House Government Operations Committee – The Performance of the Patriot Missile in the Gulf |date=April 7, 1992 |website=[[Federation of American Scientists]] |access-date=June 13, 2009 |archive-url=https://web.archive.org/web/20030115043508/http://www.fas.org/spp/starwars/congress/1992_h/ |archive-date=January 15, 2003}}</ref><ref name="fas_postollewis">{{cite web |url=http://www.fas.org/spp/starwars/docops/pl920908.htm |title=Postol/Lewis Review of Army's Study on Patriot Effectiveness |last1=Postol |first1=Theodore |last2=Lewis |first2=George |website=Federation of American Scientists |date=September 8, 1992 |access-date=June 13, 2009 |archive-url=https://web.archive.org/web/20150402044331/http://www.fas.org/spp/starwars/docops/pl920908.htm |archive-date=April 2, 2015}}</ref> This analysis is contested by [[Peter D. Zimmerman]], who claimed that photographs of the fuselage of downed Scud missiles in Saudi Arabia demonstrated that the Scud missiles were fired into Saudi Arabia and were riddled with fragments from the lethality enhancer of Patriot Missiles.<ref name="fas_insidethearmy">{{cite web |url=http://www.fas.org/spp/starwars/docops/zimmerman.htm |title=A Review of the Postol and Lewis Evaluation of the White Sands Missile Range Evaluation of the Suitability of TV Video Tapes to Evaluate Patriot Performance During the Gulf War |access-date=June 13, 2009 |first=Peter D. |last=Zimmerman |website=Inside The Army |date=November 16, 1992 |pages=7–9 |via=Federation of American Scientists |archive-url=https://web.archive.org/web/20131224183852/http://www.fas.org/spp/starwars/docops/zimmerman.htm |archive-date=December 24, 2013}}</ref>

====Failure at Dhahran====
On February 25, 1991, an Iraqi [[Al Hussein (missile)|Al Hussein Scud]] missile hit the barracks in [[Dhahran]], [[Saudi Arabia]], killing 28 soldiers from the U.S. Army's [[14th Quartermaster Detachment]].<ref name=NYT>{{cite news |last=Apple |first=R. W. Jr. |date=February 26, 1991 |title=War In The Gulf: Scud Attack; Scud Missile Hits a U.S. Barracks, Killing 27 |url=https://www.nytimes.com/1991/02/26/world/war-in-the-gulf-scud-attack-scud-missile-hits-a-us-barracks-killing-27.html |newspaper=[[The New York Times]] |access-date=June 15, 2017 |archive-url=https://web.archive.org/web/20170610220238/http://www.nytimes.com/1991/02/26/world/war-in-the-gulf-scud-attack-scud-missile-hits-a-us-barracks-killing-27.html |archive-date=June 10, 2017 |url-status=live }}</ref>

A government investigation revealed that the failed intercept at Dhahran had been caused by a [[Software bug|software error]] in the system's handling of timestamps.<ref name="GAO report IMTEC 92-26">{{cite web |url=https://www.gao.gov/products/IMTEC-92-26 |title=Patriot missile defense, Software problem led to system failure at Dharhan, Saudi Arabia; GAO report IMTEC 92-26 |website=[[Government Accountability Office|US Government Accounting Office]] |date=February 27, 1992 |access-date=January 5, 2018 |archive-url=https://web.archive.org/web/20180106065753/https://www.gao.gov/products/IMTEC-92-26 |archive-date=January 6, 2018 |url-status=live }}</ref><ref>{{cite journal |url=http://mate.uprh.edu/~pnm/notas4061/patriot.htm |first=Robert |last=Skeel |title=Roundoff Error and the Patriot Missile |journal=SIAM News |date=July 1992 |volume=25 |number=4 |page=11 |publisher=[[Society for Industrial and Applied Mathematics]] |access-date=May 8, 2013 |via=[[University of Puerto Rico at Humacao]] |url-status=dead |archive-url=https://web.archive.org/web/20100702180720/http://mate.uprh.edu/~pnm/notas4061/patriot.htm |archive-date=July 2, 2010 }}</ref> The Patriot missile battery at Dhahran had been in operation for 100 hours, by which time the system's internal clock had drifted by one-third of a second. Due to the missile's speed this was equivalent to a miss distance of 600 meters.

The radar system had successfully detected the Scud and predicted where to look for it next. However, the timestamps of the two radar pulses being compared were converted to [[Floating-point number|floating point]] differently: one correctly, the other introducing an error proportionate to the operation time so far (100 hours) caused by the truncation in a 24-bit fixed-point register. As a result, the difference between the pulses was wrong, so the system looked in the wrong part of the sky and found no target. With no target, the initial detection was assumed to be a spurious track and the missile was removed from the system.<ref>{{cite news |url=https://www.latimes.com/archives/la-xpm-1991-02-26-mn-1889-story.html |first1=Bob |last1=Drogin |first2=Patt |last2=Morrison |title=Iraqi Missile Slams Into GIs' Barracks; 27 Killed : Scud attack: 98 are hurt in the deadliest such strike of the war. Quarters were for Pennsylvania reserve unit |newspaper=Los Angeles Times |date=February 26, 1991 |access-date=January 5, 2018 |archive-url=https://web.archive.org/web/20180321025325/http://articles.latimes.com/1991-02-26/news/mn-1889_1_scud-attack |archive-date=March 21, 2018 |url-status=live }}</ref><ref>{{cite news |url=https://www.ima.umn.edu/~arnold/disasters/patriot.html |first=Douglas N. |last=Arnold |title=The Patriot Missile Failure |website=University of Minnesota |date=August 23, 2000 |access-date=January 5, 2018 |archive-url=https://web.archive.org/web/20160908191840/https://www.ima.umn.edu/~arnold/disasters/patriot.html |archive-date=September 8, 2016 |url-status=dead }}</ref> No interception was attempted, and the Scud impacted on a makeshift barracks in an [[Al Khobar]] warehouse, killing 28 soldiers, the first Americans to be killed from the Scuds that Iraq had launched against [[Saudi Arabia]] and Israel.

Two weeks earlier, on February 11, 1991, the Israelis had identified the problem and informed the U.S. Army and the PATRIOT Project Office, the software manufacturer.<ref name="GAO report IMTEC 92-26" /> As a stopgap measure, the Israelis had recommended rebooting the system's computers regularly. The manufacturer supplied updated software to the Army on February 26.

There had previously{{when|date=May 2024}} been failures{{clarify|date=May 2024}} in the MIM-104 system at the [[Joint Defense Facility Nurrungar]] in Australia, which was charged with processing signals from satellite-based early launch detection systems.<ref>{{cite news |url=http://www.hartford-hwp.com/archives/24/167.html |title=Nurrungar played fateful role in Desert Storm tragedy |first=Cameron |last=Stewart |newspaper=[[The Australian]] |date=February 18, 1999 |access-date=September 27, 2014 |via=Hartford Web Publishing |archive-url=https://web.archive.org/web/20140826114457/http://www.hartford-hwp.com/archives/24/167.html |archive-date=August 26, 2014 |url-status=dead }}</ref>

====Success rate vs. accuracy====
{{see also|Theodore Postol#Patriot missiles in Operation Desert Storm}}
On February 15, 1991, President [[George H. W. Bush]] traveled to Raytheon's Patriot manufacturing plant in [[Andover, Massachusetts]], during the Gulf War. He declared, the "Patriot is 41 for 42: 42 Scuds engaged, 41 intercepted!"<ref>{{cite web |url=http://bushlibrary.tamu.edu/research/public_papers.php?id=2711&year=1991&month=2 |title=Remarks to Raytheon Missile Systems Plant Employees in Andover, Massachusetts |first=George H. W. |last=Bush |website=George H. W. Bush Presidential Library |date=February 15, 1991 |access-date=September 27, 2014 |archive-url=https://web.archive.org/web/20141010230752/http://bushlibrary.tamu.edu/research/public_papers.php?id=2711&year=1991&month=2 |archive-date=October 10, 2014 |url-status=dead }}</ref> The President's claimed success rate was over 97% at that point in the war.

On April 7, 1992, [[Theodore Postol]] of MIT, and Reuven Pedatzur of [[Tel Aviv University]] testified before a [[U.S. House of Representatives|House Committee]] stating that, according to their independent analysis of video tapes, the Patriot system had a success rate of below 10%, and perhaps even a zero success rate.<ref name="fas_Postol">{{cite web |url= http://www.fas.org/spp/starwars/congress/1992_h/h920407p.htm |title= Optical Evidence Indicating Patriot High Miss Rates During the Gulf War |first=Theodore A. |last= Postol |website=Federation of American Scientists |date= April 7, 1992 |access-date=January 29, 2008 |archive-url= https://web.archive.org/web/20090415122817/http://www.fas.org/spp/starwars/congress/1992_h/h920407p.htm |archive-date= April 15, 2009}}</ref><ref name="fas_Pedatzur">{{cite web |url= http://www.fas.org/spp/starwars/congress/1992_h/h920407r.htm |title=The Israeli Experience Operating Patriot in the Gulf War |first=Reuven |last=Pedatzur |website= Federation of American Scientists |date=April 7, 1992 |access-date=June 13, 2009 |archive-url= https://web.archive.org/web/20141209235250/http://www.fas.org/spp/starwars/congress/1992_h/h920407r.htm |archive-date=December 9, 2014}}</ref>

On April 7, 1992, Charles A. Zraket of [[Harvard Kennedy School]] and [[Peter Zimmerman]] of the [[Center for Strategic and International Studies]], a [[think tank]] funded by the United States government and Raytheon, testified about the calculation of success rates and accuracy in Israel and Saudi Arabia and discounted many of the statements and methodologies in Postol's report.<ref name="fas_Zraket">{{cite web |url=http://www.fas.org/spp/starwars/congress/1992_h/h920407m.htm |title=Testimony of Charles A. Zraket |first=Charles A. |last=Zraket |website=Federation of American Scientists |date=April 7, 1992 |access-date=June 13, 2009 |archive-url=https://web.archive.org/web/20090112034900/http://www.fas.org/spp/starwars/congress/1992_h/h920407m.htm |archive-date=January 12, 2009 |url-status=live }}</ref><ref name="fas_Zimmerman">{{cite web |url= http://www.fas.org/spp/starwars/congress/1992_h/h920407z.htm |title=Testimony of Peter D. Zimmerman |first=Peter D. |last=Zimmerman |website=Federation of American Scientists |date=April 7, 1992 |access-date=June 13, 2009 |archive-url=https://web.archive.org/web/20100520002222/http://www.fas.org/spp/starwars/congress/1992_h/h920407z.htm |archive-date=May 20, 2010}}</ref> According to Zimmerman, it is important to note the difference in terms when analyzing the performance of the system during the war:
* Success rate – the percentage of Scuds destroyed or deflected to unpopulated areas
* Accuracy – the percentage of hits out of all the Patriots fired

In accordance with the standard firing doctrine, on average four Patriots were launched at each incoming Scud{{snd}} in Saudi Arabia an average of three Patriots were fired. The large number of missiles fired suggests low confidence in individual missiles and that a higher rate of successful interceptions was achieved through brute force. For example, if a Patriot has a 50% individual success rate, two missiles will intercept 75% of the time, and three will intercept 87.5% of the time. Only one has to hit for a successful interception, but this does not mean that the other missiles would not also have hit.

The Iraqi redesign of the Scuds also played a role. Iraq had redesigned its Scuds by removing weight from the warhead to increase speed and range, but the changes weakened the missile and made it unstable during flight, creating a tendency for the Scud to break up during its descent from [[near space]]. This presented a larger number of targets as it was unclear which piece contained the warhead.

According to the Zraket testimony, there was a lack of [[High speed photography|high quality photographic equipment]] necessary to record the interceptions of targets. Therefore, Patriot crews recorded each launch on [[standard-definition]] videotape, which was insufficient for detailed analysis. Damage assessment teams videotaped the Scud debris that was found on the ground. Crater analysis was then used to determine if the warhead was destroyed before the debris crashed or not. Part of the reason for the 30% improvement in success rate in Saudi Arabia compared to Israel is that the Patriot merely had to push the incoming Scud missiles away from military targets in the desert or disable the Scud's warhead in order to avoid casualties, while in Israel the Scuds were aimed directly at cities and civilian populations.

The Saudi Government also censored any reporting of Scud damage by the Saudi press. The Israeli Government did not institute the same type of censorship. Patriot's success rate in Israel was examined by the [[Israel Defense Forces]] (IDF) who did not have a political reason to play up Patriot's success rate.{{Citation needed|date=October 2017}} The IDF counted any Scud that exploded on the ground, regardless of whether or not it was diverted, as a failure for the Patriot. Meanwhile, the U.S. Army, which had many reasons to support a high success rate for Patriot, examined the performance of Patriot in Saudi Arabia.

Both testimonies state that part of the problems stem from its original design as an anti-aircraft system. Patriot was designed with [[proximity fuze|proximity fuse]]d warheads, which are designed to explode immediately prior to hitting a target spraying shrapnel out in a fan in front of the missile, either destroying or disabling the target. These missiles were fired at the target's center of mass. With aircraft this was fine, but considering the much higher speeds of tactical ballistic missiles, as well as the location of the warhead, usually in the nose, Patriot most often hit closer to the tail of the Scud due to the delay present in the [[proximity fuse]]d warhead, thus not destroying the missile's warhead and allowing it to fall to earth.

In response to the testimonies and other evidence, the staff of the House Government Operations Subcommittee on Legislation and National Security reported, "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 [[United States Congress]] were misled by definitive statements of success issued by administration and Raytheon representatives during and after the war."<ref>{{cite web |url= http://www.fas.org/spp/starwars/docops/operate.htm |title=Star Wars – Operations |website=Federation of American Scientists |access-date=September 27, 2014 |archive-url=https://web.archive.org/web/20141209210030/http://www.fas.org/spp/starwars/docops/operate.htm |archive-date=December 9, 2014}}</ref>

A Canadian ''[[The Fifth Estate (TV)|Fifth Estate]]'' documentary, ''The Best Defence'', in February 2003 quoted the former Israeli Defense Minister as saying the Israeli government was so dissatisfied with the performance of the missile defense, that they were preparing their own military retaliation on Iraq regardless of U.S. objections.{{Citation needed|date=December 2022}} That response was canceled only with the [[ceasefire]] with Iraq.