Patriot’s Troubled History
The Patriot is a surface-to-air missile (SAM) system fielded by a multitude of countries, including the United States, Israel, the Netherlands, Japan, and Saudi Arabia. In service since the 1980s, Patriot is the primary air defense system for the US military, and over one thousand launchers have been built. An operational Patriot battery includes a missile launcher unit, a generator unit, an antennae mast group, and a radar unit. The Patriot system is comparable to the S-300 missile system fielded by Russia and many other states in that both are modern, road-mobile, long-range radar-guided SAM systems.
The Patriot system has undergone many changes since its initial introduction to military service in 1984. Initially, the Patriot was designed solely for use against airbreathing targets, e.g. cruise missiles and airplanes. However, as the US Army’s primary high-performance air defense system, the Patriot was later tasked with ballistic missile defense as well. To add this capability, engineers added a ballistic missile defense mode, which altered the behavior of the radar so that it would scan much higher — 89 degrees as opposed to 25. This alteration allowed the Patriot’s radar to detect ballistic missiles, which follow a parabolic flight path. The higher scanning profile resulted in a tradeoff: performance against traditional threats was diminished, so operators were instructed to switch between the airbreathing target detection and ballistic target detection modes based on the anticipated threat. This version of the Patriot with upgraded software, called the Patriot Advanced Capability (PAC)-1, was capable of engaging ballistic missiles, but it still had critical shortcomings.
PAC-2 was engineered to further enhance the Patriot system’s ballistic missile engagement capabilities and to rectify issues with PAC-1. While PAC-2 included further software changes, it also made much-needed alterations to the missile itself, including adding heavier and more lethal projectiles to the missile’s blast fragmentation warhead as well as reprogramming proximity fuse algorithms to optimize them for high-speed targets such as ballistic missiles. This addressed the PAC-1 missiles’ poor lethality versus ballistic targets.
When the Gulf War erupted, the Patriot PAC-2 was brand new technology still in the process of being fielded. Patriot batteries in the Gulf War received a trial by fire. The Iraqis had a large number of SCUD tactical ballistic missiles which managed to evade destruction by US air assets. In the course of the war, the Patriot engaged numerous SCUD missiles while defending US positions and installations.
Initial US government reports on the Patriot in the Gulf War overstated performance dramatically. While officials claimed successful interception rates of over 90%, it is clear now that this was not the case. In fact, Patriot performance was rather poor. While the official combat record of the Patriot missiles in the Gulf War is still classified, research done by third parties as well as high-profile failures to intercept indicate that the Patriot batteries had serious difficulties countering Iraqi SCUD missiles. Computer glitches and guidance issues hampered the ability of Patriot batteries to engage ballistic targets. The US military’s internal review of Gulf War Patriot performance remains classified; the internal review most likely concluded that Patriot batteries performed poorly during the Gulf War, though the Army does not admit this publicly.
Patriot’s troubles during the Gulf War were brought to the public’s attention when a Patriot battery failed to intercept a SCUD missile which then killed 27 when it struck an army barracks. The failure was later attributed to a rounding error in the Patriot’s fire control unit clock; the relatively minuscule error was significant only because of the immense speeds of the missile as well as its target, which resulted in the small discrepancy being amplified into a critical error.
There were many other failed intercepts. Even when the Patriot missiles did reach their targets, the warhead was often not potent enough to neutralize the SCUD’s warhead, leaving the target damaged but still lethal. The Gulf War Patriot debacle proved that ballistic missile defense was possible, but the extremely rapid speeds of the target, as well as the interceptor, meant that all components had to perform flawlessly in battlefield conditions, something which is difficult to ensure.
To rectify the issues with Patriot PAC-2 uncovered in the Gulf War, a PAC-3 program was initiated. PAC-3 was a massive departure from PAC-2 in terms of interceptor design. The original Patriot design featured launchers with four large missiles each. While the original missiles had been altered somewhat for PAC-2, PAC-3 scrapped the quadruple launcher altogether in favor of sexdecuple launcher, placing sixteen interceptors on a single launcher. In turn, the missiles are much smaller. Overall, the move to smaller interceptor missiles means that each Patriot battery can engage more targets before depleting its missile supply. The smaller missiles are also more maneuverable and travel at very high speeds. Because of the size reduction, the PAC-3 missiles have a much shorter range than the PAC-2 missiles, which makes the PAC-3 interceptors unsuitable for intercepting traditional airbreathing threats. PAC-3 interceptors also contain no explosive warhead. Rather, they fly at high speed and impact the target, destroying it with sheer kinetic energy. The result is a highly effective but short-ranged interceptor which can only be used against other missiles. PAC-3 also vastly improved radar and guidance performance through upgrades and software tweaks.
Recent Combat Success
While undoubtedly more capable in the missile defense role than previous Patriot iterations, the capabilities of the PAC-3 still needed to be demonstrated in combat. The United States tested the PAC-3 on a small scale during Operation Iraqi Freedom, when Patriot successfully intercepted all nine SCUD missiles encountered.
A much larger body of data was obtained recently, when Saudi Arabia, which had purchased a large number of PAC-3 systems, had a chance to test the system’s mettle during the Yemeni Civil War. Houthi rebels in Yemen had a modest number of SCUD (or SCUD copy) missile systems, some likely supplied by Iran, which were fired at Saudi military targets as well as population centers.
In Saudi service, Raytheon has claimed a 100% success rate for the PAC-3 system. Astute observers will note that some SCUD missiles did inflict damage upon Saudi Arabia and its allies; however, these targets were not defended by Patriots and thus cannot be counted as failures to intercept.
The alleged success of the Saudi Patriot batteries is a landmark achievement in missile defense. Patriot PAC-3 is the first missile defense system in the world to intercept dozens of ballistic missiles back-to-back without failure, and the record is especially convincing when the flawless performances in Iraqi Freedom and Saudi service are combined. The performance of the Saudi Patriots serves to further vindicate the system after the PAC-2’s poor performance in the Gulf War. It is worth noting that Patriot’s successes have been against SCUD and similar missiles, which are more challenging to intercept than the simple rockets and mortars often intercepted by Israeli missile defense systems.
The news of PAC-3’s success in Saudi service could not come at a better time. Poland recently inked a deal to procure Patriot systems, and Germany is considering extending the service of the Patriot instead of adopting Lockheed Martin’s new MEADS system. In addition, PAC-3 Mid-Segment Enhancement (MSE), which boosts range by 15km and maximum altitude by 50%, is under development. The combat record of the Saudi Patriots will go a long ways towards reassuring current and prospective Patriot customers that the system is capable of handling ballistic missile threats effectively and that funding MSE development is worthwhile. In addition, the Raytheon engineers will be able to use information gleaned by the Saudis to improve Patriot’s performance even further, and Patriot engineers can now boast that their PAC-3 design is extensively combat-tested and proven against SCUD-type threats.
However, the job of Patriot engineers is far from complete. While SCUD missiles are challenging targets, the SCUD design is also decades old. Russia and China have produced more modern missiles designed specifically to defeat US missile defense systems, which the Patriot has yet to face. Missiles such as the Iskander tactical ballistic missile have countermeasures installed and are also capable of pulling high-g maneuvers to avoid interceptors such as the Patriot. The Patriot’s combat capabilities against these more sophisticated ballistic missiles are yet to be demonstrated.