Like a belated Independence Day skyrocket, a Ground-Based Interceptor missile roared from its silo at Vandenberg Air Force Base, Calif., on the morning of July 5 as part of an integrated exercise and test of the Ground-based Midcourse Defense element of the National Missile Defense program.
The GBI punched through coastal fog and arced over the Pacific Ocean on its way to intercept a dummy warhead that had been launched five minutes earlier from the U.S. Armyís Reagan Test Site on Kwajalein Atoll, Republic of the Marshall Islands.
The complex experiment, dubbed FTG-07, required an exoatmospheric kill vehicle to separate from the GBIís upper stage booster and maneuver to a collision course with the target.
The $214 million test was part of a multibillion dollar effort by the Missile Defense Agency, U.S. Air Force 30th Space Wing, Joint Functional Component Command for Integrated Missile Defense and U.S. Northern Command.
In the minutes following the dual launches tension mounted as officials waited for word on the results beneath the watchful bronze gaze of the Ronald Reagan Memorial overlooking the still-smoking silo at Vandenberg. They had reason for concern; previous tests have included a frustrating mix of success and failure.
As the moment of an expected collision between the warhead and EKV came and went, a mission controller somberly intoned, There is no indication of sep[aration].î Failure was confirmed when he added, No data is to leave this room, indicating that all mission data and telemetry would be impounded pending an investigation. A spokesman for the Missile Defense Agency announced that program officials planned to conduct an extensive review to determine the cause or causes of any anomalies that may have prevented a successful intercept.
The GBI is designed to intercept missile threats outside Earthís atmosphere and destroy them by the kinetic force of impact with the EKV during the midcourse phase of the enemy missileís flight. After launch, the three-stage booster carries the†EKV toward the targetís predicted location in space. As the GBI closes in on its target it releases the EKV, which uses a high-sensitivity infrared seeker to detect and discriminate between incoming warheads and decoys. The self-propelled EKV is equipped with a communication link, discrimination algorithms, guidance and control systems and targeting computers but contains no weapon or explosive elements. Once separated, the 152-pound kill vehicle uses data received from ground-based radar and its own onboard sensors to close with and destroy the target using only the force of impact.
Ground-based Midcourse Defense program testing began in 1997 and has included an incremental series of integrated flight tests made to demonstrate system capabilities. Not all experiments involved intercept of a target warhead; many were demonstrations of specific components and technologies. So far, half of 16 intercept attempts have ended in failure. Though the exact cause of the FTG-07 anomaly is not yet known, the EKV has failed to separate from its booster on two previous occasions, first in July 2000 and again in December 2002. Other failures resulted from sensor and guidance problems with the Raytheon-built EKV, and two GBI launch aborts were due to software and mechanical malfunctions. Three of five successful attempts used operationally configured interceptors. The last successful intercept occurred in December 2008 but was followed by two failures in January and December 2010. Earlier this year, the Missile Defense Agency successfully tested an EKV that had been improved based on lessons learned from previous failures. Although that test did not involve a target missile, it produced engineering data that gave engineers confidence to proceed with the July 5 intercept attempt.
The interceptor is a key component of a system designed to shield the U.S. against missile attacks such as that threatened by North Korean leader Kim Jong Un earlier this year. Currently, more than 20 GBI missiles are deployed in California and Alaska, and an additional fire control center has been established in Colorado. Several existing early warning radars located around the world, including one on Shemya Island in Alaskaís Aleutian chain, were upgraded to support flight-testing and to provide tracking information in the event of a hostile missile attack. Ultimately, as many as 30 GBIs are scheduled for deployment in an effort that the Government Accountability Office estimated would cost approximately $40 billion from 1996 through 2017.