The Patriot missile has been upgraded continually since it was first deployed in 1982, and variations include the Patriot Advanced Capability-2 (PAC-2), Guidance Enhanced Missile-Tactical (GEM-T), PAC-3 Cost Reduction Initiative (CRI) and PAC-3 Missile Segment Enhancement (MSE) missiles.
The upgraded PAC-2 missile, originally used during the Gulf War, was a U.S. Army one-stage, solid-fuel, ground-launched interceptor designed to destroy tactical ballistic missiles, cruise missiles, or aircraft with a conventional high-explosive blast fragmentation warhead.
The Patriot GEM-T variant of the PAC-2 allowed the interceptor to detect low radar signature targets more effectively and have better detonation near ballistic missiles.
The PAC-3 CRI variant increased interceptor effectiveness by employing hit-to-kill technology versus conventional blast fragmentation. The PAC-3 MSE provided further performance enhancements with greater speed and maneuverability with a larger dual-pulse solid rocket motor and larger tail fins. The PAC-3 MSE missile is the primary interceptor for the German next-generation air and missile defense system, Taktisches Luftverteidigungssystem (TLVS).