MissileThreat :: Patriot Advanced Capability-2 (PAC-2)

Country:	USA
Basing:	Land

Details

Patriot Advanced Capability-2 (PAC-2) is a surface-to-air guided missile defense system designed to detect, target, and destroy incoming ballistic missiles flying three to five times the speed of sound. PAC-2 was first deployed by the U.S. during the 1991 Persian Gulf War and successfully shot down Iraqi Scud missiles. In doing so, it became the first anti-missile system to eliminate hostile warheads in combat.

The original Patriot Air Defense Missile System, dating back to the 1970s, was designed to shoot down enemy aircraft. During the mid-1980s, however, the U.S. Army decided to expand Patriot to deal with the growing threat of tactical ballistic missiles, in particular the Soviet SS-21A (Scarab A, OTR-21, Tochka), SS-21B (Scarab B, OTR-21, Tochka-U), and SS-23 (Spider, OTR-23, Oka). Initial modifications to the system were dubbed Patriot Anti-tactical Missile Capability-1 (PAC-1) and involved software, radar, and missile trajectory upgrades.

The second expansion phase, known as Patriot Advanced Capability-2 (PAC-2), occurred between 1986 and 1988. It included a superior interceptor missile as well as upgrades to its software and guidance algorithms. The enhanced PAC-2 system had the ability to shoot down longer range ballistic missiles. In particular, it was capable of destroying the hardened metal shell that surrounded most enemy warheads.

PAC-2 arrived not a moment too soon. On August 2, 1990, Saddam Hussein invaded Kuwait, and the U.S. immediately was faced with a serious problem: Iraq had Soviet-built Scud missiles capable of delivering both conventional and chemical weapons, and these Scuds were faster than the SS-21 and SS-23 missiles. The U.S. was certain that Hussein would launch if attacked. To make matters worse, the PAC-2 interceptor missiles were still in the initial stages of production and not scheduled for completion for another five months.

Raytheon immediately went into round-the-clock full-plant production mode and, by early January 1991, it had shipped 424 PAC-2 missiles to the Persian Gulf. On January 17, U.S. and Coalition forces commenced their air attack on Iraq. The following day, Saddam Hussein began firing his Scud missiles at military and civilian targets in Israel and Saudi Arabia. PAC-2 immediately went into action.

As deployed in the Middle East, each PAC-2 battery included four main components: a radar set, a command center, a mobile launcher, and the PAC-2 interceptor missiles themselves. During the war, the radar would scan the enemy skies with its overlapping beams, paying close attention to the horizon line. The radar contained 5,000 phase-shifting elements that could track up to 100 potential targets simultaneously at a range of approximately 63 miles (or 100 kilometers). Once an incoming Scud had been detected, the radar would immediately determine the speed, altitude, heading, and origin of the threat, and communicate this information via computer to the command center.

The command center, known as the Engagement Control Station (ECS), served as Patriot’s battle management, command, control, and communications center. Inside the ECS, Army operators would view potential targets on their display screens, calculate fire missions, and send launch instructions to the mobile launchers. The operators played another important role: determining friend from foe in order to minimize the number of “friendly fire” accidents.

The PAC-2 interceptors themselves were mounted on mobile launchers. Each launcher held up to four missiles in its launch canister, which doubled as a shipping container. The launchers were deployed to provide overlapping coverage, allowing Patriot to respond rapidly to attacks from all directions. Once an incoming Scud had been detected, the PAC-2 missile would streak toward its target at a speed of Mach 5 or faster. Each missile was 17.4 feet long, weighed 2,000 pounds, and carried a 200-pound fragmentation bomb with a proximity fuse.

As it approached the incoming Scud, the PAC-2 interceptor would switch on its Track-via-Missile guidance system that would illuminate the Scud with a special wave transmitted from the ground radar. To complete its “kill,” PAC-2 would fly straight towards its target and explode at the point of nearest approach. The explosion would either completely destroy the Scud, or knock it off course so that it would miss its intended target and land somewhere in the desert.

By February 1991, the U.S. had launched 159 PAC-2 missiles. Estimates of the number of successful interceptions ranged from 40 to 70 percent, mainly due to reporting deficiencies and varying definitions as to what constituted a “kill.” PAC-2 interceptors would often divert or disable the Scuds yet fail to completely destroy them, thus complicating the “kill” tally. Nevertheless, PAC-2 saved lives and became the first weapons system in history to destroy hostile ballistic missiles in combat.

After the war, the Army continued to field PAC-2, although it also began to develop the Patriot Advanced Capability-3 (PAC-3), a further expansion of the Patriot system featuring improvements to the interceptor missile, radar system, software, and communications equipment. The main difference between PAC-2 and PAC-3 lay in the “kill” mechanism: while the PAC-2 used an exploding warhead to eliminate its targets, the PAC-3 is a “hit-to-kill” system and destroys its targets by the kinetic energy released in a head-on collision.

In 2002, Raytheon completed a separate upgrade of the PAC-2 missile, which became known as Patriot Guidance Enhanced Missile Plus (GEM+). GEM+ missiles are essentially PAC-2 interceptors that have been refurbished, modernized, and integrated with the PAC-3 system. In 2003, the U.S. launched approximately 20 PAC-2 missiles during Operation Iraqi Freedom, the majority of which were GEM+ interceptors.

Sources

Army Technology.
“The Endgame.” Inside Missile Defense, 7 January 2004.
GlobalSecurity.org.
HowStuffWorks.
Raytheon Company.
“Raytheon Delivers Upgraded PAC-2 Missiles To Army.” Aerospace Daily, 15 November 2002.
Redstone Arsenal, Alabama.
Sherman, J. Daniel. “Patriot PAC-2 Development And Deployment In The Gulf War.” Acquisition Review Quarterly, Winter 2003, 28-45.

Patriot Batteries To Go To South Korea

April 30, 2004 :: News

The United States will be adding to its Patriot interceptors in South Korea, with two additional batteries of Patriot Advanced Capability 2 and 3, according to a press release by the US and South Korean Combined Forces Command in Seoul. The batteries will be added at Gwangju Air Base, with the U.S. Eighth Army’s 35th Air Defense Brigade.
Six Patriot batteries were stationed in South Korea’s major bases since 1994. A battery is composed of eight launchers of PAC-2 and PAC-3 missiles, each having 4 and 16 interceptors, respectively.
In 1998, North Korea fired a Taepo-Dong I missile over Japan. (Article, Link)

» May 6: KCNA news agency, Pyongyang: U.S. to deploy Patriots against North Korea “escalated military threat”

» May 4: EastAsia Intel report on Patriot xfer

» More stories on: Land-Based Systems, North Korea

» Missile details: Taep'o-dong 1

» Missile system details for: Patriot Advanced Capability-2 (PAC-2), Patriot Advanced Capability-3 (PAC-3)

Japan MD by 2006

August 30, 2003 :: Japan Times ::

The Japan Defense Agency has submitted a defense budget request which includes 500 billion yen for missile defense, to be deployed by 2006. The Japanese deployment, directed largely at North Korean ballistic missile threats, would be two-tiered, combining forms of the Aegis Sea-Based system and the PAC Patriot Ground Based System. The JDA hopes to equip 16 of its 27 Self Defense Forces with Patriot systems, and to deploy four Aegis Cruisers. (Article, Link)

» More stories on: Allies

» Missile system details for: Aegis Ship-Based BMD, Patriot Advanced Capability-2 (PAC-2), Patriot Advanced Capability-3 (PAC-3)

Japan Pushing for Defenses

August 12, 2003 :: Sioux City Journal :: News

The Japanese Defense Agency is planning a budget request of $1.2 billion for the development of a dual-layered missile defense system, a sum up from the $132 million allocated last year for research. The spike of attention comes amidst increased stirrings from North Korea, which test launched their Taepo’ dong I missile over the main Japanese island in 1998, and have since been making noise about a miniaturized nuclear weapons program. A recent white paper by the Japanese Defense Agency called missile defense a “pressing need,” and identified North Korea as a major and growing threat.
The proposed Japanese system would combine state-of-the-art Aegis cruisiers, with a sea-based boost-phase or midcourse-phase component, with a newer version of the Patriot missile, designed to intercept missile warheads in their terminal phase as they reenter the atmosphere toward their target. Japan currently has around 27 batteries of the PAC-2 version of the Patriot, but these are limited to interceting missiles with a range and speed significantly less than the longer-reaching (and thus more quickly moving) Taepo’ Dongs. (Article, Link)

» Japanese Defense Agency white paper cites need for missile defenses

» More stories on: Allies

» Missile details: Tien Chi

» Missile system details for: Aegis Ship-Based BMD, Patriot Advanced Capability-2 (PAC-2)