The US Army's most advanced air defense system, the MIM-104 Patriot system, is capable of defeating both high-performance aircraft and tactical ballistic missiles.

It is the only operational US air defense system that can shoot down attacking missiles, according to the US Army Aviation and Missile Life Cycle Management Command.

Developed by US defense contractor RTX (formerly Raytheon), the MIM-104 Patriot (an acronym for Phased Array Tracking Radar to Intercept on Target) first entered service in the early 1980s, according to the National Interest.

Although it was developed to defeat high-performance aircraft, the United States made two modifications to prepare the system against tactical missiles before it was deployed to the Middle East during the Gulf War in 1991.

Since its first combat deployment three decades ago, "hundreds" of upgrades since then have significantly improved its performance to about a 95% hit ratio, according to the National Interest.

Today, more than 240 Patriot systems are in use in 18 countries including the United States, Saudi Arabia, the United Arab Emirates (UAE), Israel, Kuwait, Qatar, Bahrain, Taiwan, Greece, the Netherlands, Germany, Spain, Japan, South Korea, Romania, Poland, Sweden and Switzerland.

The system has been in high demand in the Middle East because of threats to the region posed by Iran and its proxies.

The Patriot system has intercepted more than 150 ballistic missiles in combat since 2015, according to RTX.

High-tech capabilities

Patriot systems have four operational functions, according to a NATO Patriot deployment fact sheet -- communications, command and control, radar surveillance and missile interceptor guidance.

A Patriot battery, or basic firing unit, has six major components: power plant, radar set, engagement control station, launcher stations, antenna mast group and the interceptor missiles themselves.

The radar set provides detection and tracking and helps guide interceptors to their targets; the manned engagement control station calculates trajectories for interceptors; the launcher stations transport, protect, and provide a launching platform for the interceptor missiles; and the antenna mast group is the main communication backbone for the system.

The Patriot fires PAC-2 interceptor missiles, which are proximity fuse missiles that detonate in the vicinity of a threat missile, and PAC-3 interceptor missiles, which destroy threat missiles by impacting them directly with "hit-to-kill" technology.

The PAC-3 (MIM-104F) upgrade of the Patriot system, initially fielded in 2001, significantly increased Patriot capabilities with upgraded missiles and use of the Link 16 communications system.

Link 16, designed to share real time tactical data among the US military, NATO and other allies, enables a range of platforms, including aircraft, surface ships, ground vehicles, missile defense systems, networked weapons and command-and-control networks to exchange text, imagery and digital voice messages.

"Interoperability provided by Link 16 allows each participant in the communication link to electronically observe the battlespace, identify threats, and acquire targets," according to the Missile Defense Advocacy Alliance.

A modified Patriot launcher can fire 16 PAC-3 Cost Reduction Initiative (CRI) missiles and target eight inbound ballistic missiles. A Patriot battery of six launchers can defeat 48 ballistic missiles.

The even more advanced PAC-3 Missile Segment Enhancement (PAC-3 MSE), fielded in 2015, features larger, dual pulse solid rocket motors; larger fins; and upgraded actuators and thermal batteries to achieve greater speeds and maneuverability for defeating more advanced ballistic and cruise missiles.