The Ground-Based Interceptor (GBI) is the interceptor component of the Ground-Based Midcourse Defense System (GMD) administered by the Missile Defense Agency. The GBI’s role is to intercept missile threats outside of the Earth’s atmosphere and destroy them by the kinetic force. GBIs are deployed as dormant missiles that launch from underground silos in the event of a ballistic missile attack. As of 2009, GMD is the only defensive system that can intercept Intercontinental-Range Ballistic Missiles in their midcourse phase of flight.
The GBI is made up of a three-stage, solid fuel booster and an exoatmospheric kill vehicle (EKV.) When launched, the booster missile carries the EKV toward the target’s predicted location in space. As the missile closes in on its target, the GBI launches the EKV, armed with a high-sensitivity infrared seeker and an agile divert system, it carries. Once released from the booster, the 152 pound kill vehicle uses data received in-flight from ground-based radars and its own on-board sensors to close with and destroy the target using only the force of the impact.
The Exoatmospheric Kill Vehicle (EKV) is the intercept, or kill component, of the Ground-Based Interceptor (GBI), the weapon element of the Ground-Based Midcourse Ballistic Missile Defense System. The EKV mission is to engage incoming ballistic missiles in their midcourse phase of flight and to destroy them using only the force of impact. There is no weapon or explosive element of the EKV.
Each EKV consists of an infrared seeker used to detect and discriminate incoming warheads from decoys and other objects. The EKV has its own propulsion, communication link, discrimination algorithms, guidance and control system and computers to support target selection and intercept. The EKV is continuously updated with the latest information from the command and control center.
June 2013: The GBI and EKV system has been highlighted for upgrades including sensitivity issues when acquiring targets in the early launch stages, liquid fuel upgrades, and more diverse missile intercept capability.
August 2013: The GBI and EKV system underwent further testing this summer on its most recently updated systems. The test failed, and put Vice Admiral Syring on the Senate hotseat as the FY14 budget appropriations was slated to have multiple expensive provisions for the GBI system. Among other Senators on the SASC, Senator Durbin questioned Syring briefly in a public hearing about the reliability of the GBI program, specifically with regards to the continued purchase and deployment of the GBI system, potentially to an East Coast site.
The GBI program has faced increased scrutiny over the past couple of months due to the effects of sequestration, and lawmakers are eager to find "easy" places to cut spending. Vice Admiral Syring, who was later questioned in a longer, classified hearing, was firm in his advocacy for the GBI program and its reliability now and in the future. Though Senator Durbin illustrated some of his skepticism, he acknowledged what he felt was extensive progress in MDA's achievements and ongoing projects such as Aegis.
As of August 7, 2013, the GBI program is to move forward with construction, acquisition and deployment of 14 more GBI interceptors. MDA and the armed forces believe that it is a viable defense system, and until such time as an East Coast missile defense site is a functioning reality, the GBI's will e relocated to strategic points to best serve that side of the country while developments are underway.