United States Patriot (PAC-1, PAC-2, PAC-3)

Originated From:United States
Warhead:Kinetic hit-to-kill (PAC-3)
Range:15 km (PAC-3), 22 km (MSE)
In Service:1985

The idea of a mobile, air defense system utilizing missile interceptors first started in 1961 at the U.S. Army Missile Command. In 1965, the XMIM-104 Patriot development program had been established. The system was initially designed as an anti-aircraft, surface-to-air defense battery, but subsequent upgrades allow for a wide array of air targets. Development test launches began five years later in 1970, with full-scale engineering development starting in 1976. 1 By 1985, the U.S. Army declared the Patriot fully operational. 2

The original MIM-104 Patriot has been in a continuous improvement program since its inception into U.S. and allied forces. The Patriot Level-1 anti-tactical missile (ATM, or better known as PAC-1) primarily consisted of software changes allowing for the interceptors to be used to defend against short-range ballistic missiles (SRBMs). The PAC-1 was deployed in Europe in 1988. Its successor, the PAC-2, was deployed to the Gulf in Operation Desert Shield. The PAC-2 consisted of further software upgrades and improvements to the warhead.

The PAC-2 was the first ballistic missile defense system to successfully intercept a hostile ballistic missile during war. Iraq fired 88 modified ‘Scuds’ into Saudi Arabian and Israeli airspace, of which 53 were in Patriot defended areas. The PAC-2 intercepted a total of 51 SRBMs, and fired a 157 interceptors. 3

Patriot firing units in Israel, 2003.

The PAC-3 was originally designed as long-range tactical ballistic missile interceptor system, but was later changed to include cruise missiles. Considered one of the most sophisticated missile defense systems in the world, the PAC-3 configuration has over a 90 percent interception rate over the last few years. The PAC-3 system differs significantly from the PAC-1/-2 interceptors due to its hit-to-kill technology. Previous Patriot interceptors used a blast or fragmentation detonation in the vicinity of the hostile target, whereas the PAC-3 hits the target directly — hence, ‘hitting a bullet with a bullet’ analogy.

There are two main variants of the PAC-3 configuration: an air-launched variant, and a long-range version. The air-launched hit-to-kill (ALHTK) development program is a PAC-3 interceptor launched from F-15C aircraft, and possibly F-16, F-22, and F-35 aircraft. The idea is to integrate a proven defensive system, with the mobility of an air-launched platform. Additionally, the PAC-3 interceptors could achieve up to six times the range of the land-based system due to the reduction in fuel use needed to obtain its cruising speed. 4 Another variant, the Missile Segment Enhancement (MSE) program, replaces the current motor with a more powerful one, allowing for increased range. The standard PAC-3 has a range of 15 km; the PAC-3 MSE has a range of 22 km. 5

ALHTK depiction shown at launch.
Lockheed Martin

The Patriot missile defense system consists of 4 major components: the M901 launchers, consisting of eight firing units (two platoons of four firing units), each having a four-tube launcher (total of 32 interceptors available until reload); the AN/MPQ-53 phased-array radar, designed to track enemy missiles or aircraft; the AN/MSQ-104 Engagement Control Station (ECS), the “man in the loop” for firing an interceptor; and the AN/MSQ-24, the 150 kW diesel powered generator units. 6

Engagement Control Station.

The AN/MSQ-104 ECS is essentially the brain of the Patriot system. It is the only manned portion of the Patriot batteries, consisting of three (sometimes four) individuals. The Patriot system is nearly autonomous, with only the final launch decision requiring human interaction. The ECS has two computer consoles, each displaying a radar depiction of airborne vessels. The tactical control officer sits to the right; the tactical control assistant sits to the left; and the communications operator sits in the back. The tactical control assistant does the actual ‘firing’ of the interceptors; the tactical control officer approves targets and ensures that allied forces are not targeted; and the communications operator monitors all communication between headquarters and the other batteries. Sometimes a recorder assists the tactical control assistant and records messages from headquarters. 7

AN/MPQ-53 phased-array radar.

The AN/MPQ-53 phased-array radar is a significant departure from the standard, constant-beam radar. The phased-array radar emits a rapid and random radar beam, thousands of times per second, making it very difficult for an enemy to jam the signal. After an interceptor is launched, it begins relaying flight data back to the radar allowing for very accurate terminal guidance. 8

The interceptors are sealed and shipped by Lockheed Martin in their box launchers, and require no maintenance prior to launching. The PAC-3 is 5.205 in length, 0.255 m in diameter, and 315 kg in weight (the PAC-3 MSE is 3 kg lighter). The PAC-3 utilizes a hit-to-kill warhead, designed to physically strike the target, ensuring that the missile’s warhead is destroyed. The PAC-3 has a maximum velocity of 1,700 m/s, while the PAC-3 MSE is known to be faster than this, its exact speed is unknown.

Some version of the Patriot system is possessed by 19 countries including Bahrain, Denmark, Germany, Greece, India, Israel, Japan, Jordan, Kuwait, Netherlands, Poland, Qatar, Saudi Arabia, South Korea, Spain, Taiwan, Turkey, UAE, and the USA. 9

NATO firing units deployed at Diyarbakir military airport in southeastern Turkey.

The most recent deployment of Patriot missiles was in February 2013. NATO agreed to place six batteries near the Turkish-Syrian border to protect against ballistic missiles. Since the conflict began, the regime has fired dozens of ballistic missiles at ‘rebel’ forces that control northern parts of Syria. Fortunately, none the Syrian ballistic missiles have entered Turkish airspace.

  1. O’Halloran, James. “MIM-104 Patriot” Jane’s Land Warfare Platforms: Artillery and Air Defence. November 19, 2012. (accessed March 1, 2013).
  2. “Fact Files: Patriot,” United States Army. http://www.army.mil/factfiles/equipment/airdefense/patriot.html (accessed April 23, 2013).
  3. O’Halloran. “MIM-104 Patriot”
  4. “Products.” Lockheed Martin: Missiles and Fire Control. 2012. Volume 7, Edition 2. http://www.lockheedmartin.com/content/dam/lockheed/data/mfc/psp/psp/2012_Product_Catalog.pdf (accessed April 23, 2013).
  5. O’Halloran, James. “Patriot PAC-3” Jane’s Land-Based Air Defence. November 23, 2012. (accessed March 1, 2013).
  6. O’Halloran. “MIM-104 Patriot.”
  7. “Patriot Missile 1/3.” Fire Power. http://www.youtube.com/watch?v=MCFLDM5n9VI (accessed April 23, 2013).
  8. Ibid., see also part 2: Fire Power “Patriot Missile 2/3” http://www.youtube.com/watch?v=VEs2vP19zYw (accessed April 23, 2013).
  9. O’Halloran. “MIM-104 Patriot.”
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