Ground Based Interceptor [GBI]
The Ground Based Interceptor [GBI] is the weapon of the National Missile Defense (NMD) system. Its mission is to intercept incoming ballistic missile warheads outside the earth's atmosphere (exo-atmospheric) and destroy them by force of the impact. During flight, the GBI receives information from the NMD Battle Management, Command, Control, and Communications (BMC3) to update the location of the incoming ballistic missile, enabling the GBI onboard sensor systemto identify and home in on the target. The GBI would consist of a multi-stage solid propellant booster and an exoatmospheric kill vehicle. No nuclear weapons would be used as part of the NMD system.
The Ground Based Interceptor will have an acceleration profile and burnout velocity that maximize the interceptor's reach, consistent with the long-range capability of the supporting sensors. The GBI payload will be an Exo-Atmospheric Kill Vehicle (EKV) equipped with a high-sensitivity infrared seeker and an agile divert system to support endgame intercepts of responsive threats at very high closing velocities. In addition, the payload will be hardened to elevated doses of X-rays to allow operation in nuclear environments. To limit the adverse effects of this environment on the interceptor, the defense battle management will distribute the engagements within the available battlespace; the larger the battlespace, the wider the separation, and the weaker the deleterious effects of a nuclear environment. Also, to achieve high confidence of success against all threat objects, salvos of interceptors may be launched against each credible threat object. These salvos will be spaced in time to reduce the likelihood of correlated errors among the intercept attempts.
The GBI seeker is expected to be able to do discrimination against initial simple threat countermeasure and penetration aid, though it would require assistance from ground-based radars or space-based sensors to address more complex and sophisticated targets.
The deployed GBI would be a dormant missile that would remain in the underground launch silo until launch. Launches would occur only in defense of the United States from a ballistic missile attack. There would be no flight testing of themissiles at the NMD deployment site. The technical status of each missile would be monitored and any required maintenance conducted at a contractor's offsite production facility. Interceptors in storage would be used to replace missiles requiring repair or selectively removed for reliability testing.
Each missile would contain approximately 12,595 kilograms (27,766 pounds) of solid propellant. The exoatmospheric kill vehicle would contain approximately 9 to 14 kilograms (20 to 30 pounds) of liquid propellant. These liquid propellants would consist of monomethylhydrazine and nitrogen tetroxide.
The GBI site would contain launch stations (silos), Interceptor Receiving and Processing Building, Interceptor Storage Facilities, and additional support facilities. Approximately 243 hectares (600 acres) would be required to support the GBI missile field and associated technical facilities. When the GBI site and associated technical facilities become fully operational, total site related employment would be approximately 150 to 200 personnel. Explosive Safety Quantity-Distance (ESQD) criteria would be used to establish safe distances from explosive hazard areas, such as solid propellants, to nonrelated facilities and roadways. These regulations are established by the Department of Defense. For the GBI silos, there would be a minimum 380-meter (1,250-foot) ESQD from inhabited buildings. In addition, the Interceptor Receiving and Processing Building and the Interceptor Storage Facilities would also have a 380-meter (1,250-foot) ESQD from inhabited buildings.
The interceptor, consisting of the solid propellant booster and exoatmospheric kill vehicle, would be shipped to the site in specially designed canisters using commercial carriers or government transportation. All shipping would be conducted in accordance with Department of Transportation regulations. Presently, there are no plans to store liquid propellants on-site. A small quantity of liquid propellants would be used by the exoatmospheric kill vehicle. The interceptor would arrive at the GBI site with the liquid propellants loaded and sealed inside the exoatmospheric kill vehicle. Additionally, the interceptor would be contained within a canister. Upon receipt, the canisterized interceptor would be monitored to inform workers if a leak had occurred during shipping. If a leak has occurred, a specially trained hazardous material response team and equipment would be used to remove any propellant from the canister. The propellant would then be contained and treated, as required. The Department of Defense and other government agencies have a long history of working with the solid and liquid propellants proposed for the GBI element and have developed standard operating procedures for the safe handling of these materials.
During normal daily operations, the only air and noise emissions would be associated with the electrical generators required to provide power to the site. These generators would only be required as backup power sources if commercial power to the site failed or if required to support a mission. At sites where no commercial power is available, or where the reliability of commercial power does not meet NMD system requirements, the generators would operate continuously.
To ensure an accidental launch of a GBI does not occur, the system would have a human in control at all times in addition to software and hardware safety systems. Additionally, stringent Department of Defense operating procedures, which prevent the launch by any one person, would be followed.
By 2007 the configuration of the GMD interceptor continued to struggle with an anomaly that had occurred in each of the element’s flight tests. The anomaly had not yet prevented the program from achieving its primary test objectives, but neither its source nor a solution had been clearly identified or defined. The reliability of some GMD interceptors remained uncertain as well because inadequate mission assurance/quality control procedures may have allowed less reliable or inappropriate parts to be incorporated into the manufacturing process. Program officials planned to introduce new parts into the manufacturing process, but not until interceptor 18. MDA also planned to retrofit the previous 17 interceptors, but not until fiscal year 2009. -->
Sources and Resources
Ground Based Interceptor: Ballistic Missile Defense Organization (BMDO) The Ground Based Interceptor (GBI) program takes advantage of prior interceptor technology and system investments. The exoatmospheric kinetic kill vehicle (EKV) portion of the interceptor destroys the attacking missile warhead by hitting it at high speed. The program's emphasis is to demonstrate early term intercept of high-speed, long-range ballistic missiles.
GBI/EKV Ground Based Interceptor/Exoatmospheric Kill Vehicle. Ground Based Interceptor (GBI) / Exoatmospheric Kill Vehicle (EKV) Hughes Missile Systems Company.
EKV DACS Aerojet Tactical, Defense and Armaments. EKV Divert and Attitude Control Systems.
