The New York Times March 23, 2003
Patriot Missiles Bag Their Prey Again, Reportedly Shooting Down 4 of 6 Iraqi Rockets
By Nicholas Wade
An upgraded version of the Patriot missile has intercepted four out of six Iraqi missiles fired at coaltion forces in recent days, military spokesmen said. If verified, this would apparently be the first undisputed success of a battlefield antimissile system, but skeptics say it is too early to know how well the system worked.
In the Persian Gulf war in 1991, an earlier version of the Patriot was used to defend against the 93 Scud missiles fired by Iraq. United States Army spokesmen have said the Patriot had a 79 percent success rate against Scuds fired at Saudi Arabia and a 40 percent success rate against those fired at Israel. Critics doing their own analysis of intercepts from television broadcasts, however, put the Patriot's intercept rate at as low as zero.
The Patriot system may have succeeded this time around because it uses an entirely new missile designed to overcome the faults of the PAC-2, the missile used during the first gulf war.
The PAC-2 was originally designed for use against aircraft and later modified for antimissile duty. Its successor, the PAC-3, is specifically designed to shoot down other missiles. Built by Lockheed Martin, its present cost is $3 million apiece, said a spokeswoman for the Army's Aviation and Missile Command at Huntsville, Ala.
It was the PAC-3's that intercepted the four Iraqi missiles, which were not Scuds, but a shorter-range missile known as the Ababil-100.
Dr. George Lewis, a missile expert at the Massachusetts Institute of Technology's Security Studies Program, said the PAC-3 had performed quite well in its developmental tests, conducted by the contractor under ideal conditions, and somewhat less well in the more realistic operational tests, undertaken by soldiers using production-line missiles.
He dismissed as "absolute garbage" the Army's claim for the PAC-2's effectiveness in the gulf war in 1991 and said the PAC-3's success, if verified, would probably be the first time a battlefield antimissile system had worked.
John Pike, director of the space and military research group GlobalSecurity.org, said that "everyone should reserve judgment" on the Patriot's performance and that the reports of success, while in line with the missile's test results, were based on numbers too small to mean much.
The PAC-2 is designed to destroy its target by exploding next to it, a generally effective measure against aircraft. Its successor makes a direct collision with the missile it is intercepting, using its own momentum to obliterate it.
The PAC-3 is also much more agile and can pursue a missile that tries to outmaneuver the defense. This was a property that Iraq's Al Hussein Scud missiles possessed inadvertently. Made of Scuds soldered together to extend their range, Al Husseins tended to break apart and follow unpredictable paths, bewildering the PAC-2's trying to intercept them.
The PAC-3 has a collar of 180 small rocket motors that fire explosively in the last microseconds before impact, guiding the nose of the missile into direct collision with its target, a Lockheed Martin spokesman said.
The Patriot system consists of radar, a launcher and other components. The system, and an upgraded version of the PAC-2, are still made by Raytheon. Four of the PAC-3's can fit in each launcher, quadrupling the system's firepower. Both types of missile can be used in the same launcher, allowing the operator to use the PAC-3 on missiles and the PAC-2 against aircraft.
When the Patriot's phased array radar picks up an incoming missile, it downloads the information to a PAC-3 just before it is fired. The missile has on-board radar for organizing its collision with the target.
Battlefield missile defense is a simpler task than national missile defense because the closing speeds of the two missiles are slower and the target missile remains in the atmosphere, giving it no chance to release effective decoys. Intercontinental missiles, however, spend most of their trajectory in space and can conceal their warhead in a cloud of accompanying decoys.
In the unending dispute over national missile defense, supporters may contend that the PAC-3's success is a promising advance while detractors may argue that the two problems are entirely different.
"There are features that everyone will point to to claim they have been right all along," Mr. Pike said.
http://www.nytimes.com/
GRAPHIC: Chart/Diagram: "The Next Generation Patriot Missile, the PAC-3" Unlike previous Patriot missile systems that attempted to destroy their target by detonating nearby, the PAC-3 attempts to hit the target directly.
1. The radar detects an incoming missile and tracks its speed, altitude and trajectory.
2. With data from the radar, soldiers in the engagement control center determine a launch time and transmit instructions to the launcher.
3. Once fired, the missile's own guidance system searches for and acquires the target and maneuvers to intercept it.
Diagram highlights the following:
INCOMING MISSILE
RADAR
LAUNCHER
ENGAGEMENT CONTROL CENTER
PATRIOT MISSILE
(Source: Raytheon)
Copyright © 2003, The New York Times Company
