How Patriot Missiles Work

The Patriot Missile

A Patriot missile is a single-stage solid rocket that currently comes in two forms. There is the older PAC-2 missile, which is larger and not as effective as the newer PAC-3 missile deployed in 2002.

The PAC-2 missile:

  • is 17 feet long (5.2 meters)
  • is 16 inches (41 centimeters) in diameter
  • has fins that extend out another 16 inches (41 centimeters)
  • weighs almost 2,000 pounds (900 kilograms)
  • carries a 200-pound (90-kilogram) fragmentation bomb with a proximity fuse
  • flies at Mach 5 and is supersonic within a second after launch

Four PAC-2 missiles fit on a launcher.

The idea is for the PAC-2 to fly straight toward the incoming missile and then explode at the point of nearest approach. The explosion will either destroy the incoming missile with the fragments from the fragmentation bomb, or knock the incoming missile off course so it misses the target.

The PAC-3 missile is the same length as the PAC-2 but weighs only a third as much at 686 pounds (312 kilograms). It is only 10 inches (25 centimeters) in diameter. The smaller size means that 16 PAC-3 missiles can fit on a launcher. The fragmentation warhead weighs only 160 pounds (73 kilograms) in the PAC-3.

The idea behind a PAC-3 is for the missile to actually hit the incoming target and explode so that the incoming missile is completely destroyed. This feature makes it more effective against chemical and biological warheads because they are destroyed well away from the target.

The biggest difference between the PAC-2 and the PAC-3, and the thing that allows the PAC-3 to actually hit its target, is the fact that the PAC-3 has its own built-in radar transmitter and guidance computer. The operational differences between the PAC-2 and PAC-3 are discussed later in the article.

PAC-3 missiles currently cost $2 to $3 million each. (See this Web site and this site for details.)

In the next section, we'll take a look at the launcher, radar and ECS systems.