The terminal high altitude area defense (THAAD) is a mobile defense system designed to intercept ballistic missiles during their terminal phase of flight. It utilizes an X-band radar, specifically the AN/TPY-2, along with a single-stage, hit-to-kill interceptor to neutralize ballistic missiles both within and outside the atmosphere.

THAAD serves as a middle-tier component of the United States’ Ballistic Missile Defense System (BMDS), providing a broader area of protection compared to the Patriot system while also acting as a supplementary layer for the exoatmospheric Aegis Ballistic Missile Defense and Ground-based Midcourse Defense systems. It has successfully demonstrated its capability to engage short-, medium-, and intermediate-range ballistic missiles during flight tests.

The development of THAAD began in response to Congressional requests for a "deployable Theater Missile Defense demonstration system.

The Army initiated the program, entering the Program Development and Risk Reduction (PDRR) phase in 1992. The first test launch of a THAAD prototype occurred in April 1995. However, the initial intercept test on December 13, 1995, was unsuccessful, followed by five additional failed flights from 1996 to 1999, primarily due to manufacturing quality control issues with the interceptor.

What Is Terminal High Altitude Area Defense?

In light of two successful flights in June and August 1999, the Army decided to redesign THAAD and adjusted its requirements for intercepting targets at lower altitudes. The system transitioned into the Engineering and Manufacturing Development (EMD) phase in June 2000.

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During this phase, the terminal high altitude area defense interceptor prototype was enhanced with more robust thrust vector control and divert systems, upgraded computing capabilities, and streamlined avionics. The THAAD EMD missile successfully passed its critical design review in December 2003, and the first AN/TPY-2 radar was delivered in March 2004.

This advanced interceptor completed its inaugural flight test on November 22, 2005, followed by its first successful intercept test on July 12, 2006, during which it effectively engaged a ballistic missile target.

From 2006 to 2019, the Army and the Missile Defense Agency executed 18 intercept tests of the THAAD system, achieving success in 14 of these tests, while 4 were aborted prior to launch due to issues with the target. Notably, the production version of the THAAD system has maintained a perfect record in intercept tests.

The THAAD interceptor measures 6.2 meters in length, has a diameter of 0.4 meters, and weighs 662 kg at the time of launch. It features a single-stage, solid-propellant booster paired with a liquid-fueled kinetic kill vehicle. The booster is made from carbon fiber and utilizes hydroxyl-terminated polybutadiene (HTPB) as its propellant. For control, it incorporates a thrust vectoring system and a deployable rear flare to enhance stability.

Understanding the Terminal High Altitude Area Defense

The kill vehicle is constructed from composite materials and is equipped with a gimbaled infrared seeker to track targets during the terminal phase. Upon nearing the target, the terminal high altitude area defense kill vehicle detaches from the main booster and employs hydrazine-powered divert thrusters to adjust its trajectory.

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The THAAD system is designed to protect targets at ranges between 150 and 200 kilometers. Unlike many other missile defense systems, THAAD is capable of intercepting targets both within the atmosphere (endoatmospheric) and outside of it (exoatmospheric).

THAAD Launcher

The THAAD launcher is constructed on a heavy expanded mobility tactical truck (HEMTT) featuring four axles. Each launcher is capable of carrying up to eight interceptors, which are stored in launch canisters measuring 6.6 meters in length and weighing 1,044 kilograms. A standard THAAD battery comprises six launchers, with each launcher requiring approximately 30 minutes for reloading.

AN/TPY-2 Radar

The THAAD system employs the Army Navy/Transportable Radar Surveillance (AN/TPY-2) radar for the detection and tracking of enemy missiles at distances ranging from 870 to 3,000 kilometers.

The AN/TPY-2 radar can be deployed in two operational modes: a forward-based mode (FBM), which identifies missiles during their ascent phase to assist other Ballistic Missile Defense System (BMDS) components, and a terminal mode (TM), which offers tracking and engagement data for terminal THAAD operations.

The AN/TPY-2 radar consists of four primary subsystems: the Antenna Equipment Unit (AEU), the Electronic Equipment Unit (EEU), the Cooling Equipment Unit (CEU), and the Prime Power Unit (PPU).

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The AEU serves as the principal radiating component of the AN/TPY-2 and functions within the X-band frequency. Its high resolution enhances its ability to effectively cue engagements and differentiate between actual targets and decoys or debris. The system, mounted on a trailer, features a phased-array antenna face measuring 9.2 square meters, equipped with over 25,000 antenna modules.

Additionally, three other trailers—the EEU, CEU, and PPU—supply the necessary processing capabilities, refrigerated coolant, and electrical power to maintain operational functionality. The antenna and electronic units are interconnected with THAAD fire control elements via fiber optic cables, while the cooling and power units provide chilled coolant and electrical power to the radar subsystems.

FAQ's- Terminal High Altitude Area Defense

What is terminal high altitude defence?

The Terminal High Altitude Area Defense (THAAD) is an advanced and combat-tested system designed to counter short, medium, and intermediate-range ballistic missile threats. It is unique among U.S. defense systems in its capability to intercept targets both within and beyond the Earth's atmosphere.

Can THAAD intercept a hypersonic missile?

The THAAD system possesses superior detection and tracking capabilities for incoming threats compared to many other systems. However, successfully intercepting Russian hypersonic missiles presents significant challenges, potentially rendering it ineffective against such advanced weaponry.

What is the cost of the Terminal High Altitude Area Defense system?

The expense associated with THAAD batteries is substantial. As reported by Al Jazeera, the price for a single THAAD battery ranges between $1 billion and $1.8 billion. An April report from the Congressional Research Service details that a standard THAAD battery comprises 95 personnel, six truck-mounted launchers, and 48 interceptors, with eight interceptors allocated per launcher.

What is the most effective defense against hypersonic missiles?

Hypersonic missiles introduce a novel threat that necessitates innovative defensive measures. One proposed solution involves deploying a satellite swarm that can engage hypersonic missiles at their most vulnerable point—near the edge of space.

What is the leading air defense system globally?

The S-400, also known as the S-400 Triumf or Triumph, is a mobile surface-to-air missile (SAM) system developed by Russia's Almaz Central Design Bureau. It is widely regarded as the premier air defense missile system in the world.