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Pentagon Repeats Missile Defense Test Success
Repeating essentially the same scenario as a successful test last year, the Pentagon Sept. 28 conducted a strategic anti-ballistic missile test that destroyed a target high above the Pacific Ocean. Pentagon officials say they will raise the degree of difficulty for the missile defense system’s next trial early next year.
The recent test result raises the record of the Ground-based Midcourse Defense (GMD) to seven hits in a dozen intercept attempts dating back to October 1999. But the success also marks just the second intercept by the system since President George W. Bush ordered its deployment in December 2002. There are now 21 total GMD missile interceptors fielded in Alaska and California. Current plans call for more than doubling this amount up to 44 interceptors by 2011.
The Bush administration also is striving to place an additional 10 modified missile interceptors in Poland. Russia has strongly denounced this deployment as a potential threat to its security. Talks between Washington and Moscow have made little headway in mollifying Russian concerns (see page 31 ), but two Russian government officials joined Lieutenant General Henry Obering, the director of the Pentagon’s Missile Defense Agency (MDA), to watch the latest test of the U.S.-based system.
In the experiment, the MDA fired a target missile south from Kodiak, Alaska, over the Pacific Ocean. Guided by a California-based, upgraded early-warning radar, an interceptor was then launched from Vandenberg Air Force Base, California. After the boosters of the interceptor burned out, it released a roughly 60-kilogram exoatmospheric kill vehicle (EKV) that used a radar update and its own onboard infrared sensors to hone in on and collide with the target missile’s mock warhead, destroying it through the sheer force of impact.
The target missile flew the same trajectory as the one launched in the system’s previous test Sept. 1, 2006. (See ACT, October 2006. ) MDA spokesperson Rick Lehner explained in an Oct. 11 e-mail to Arms Control Today that safety and Federal Aviation Administration regulations limit the paths test missiles and interceptors may travel.
The target missile’s flight was intended to emulate a trajectory similar to a hypothetical North Korean ballistic missile attack against the United States. North Korea has not succeeded in flight-testing a missile capable of striking the continental United States, but in July 2006, it test-fired several ballistic missiles, including the Taepo Dong-2. Estimated to be Pyongyang’s longest-range missile, the Taepo Dong-2 failed 40 seconds into its inaugural and, so far, only flight test.
Bush administration officials maintain that North Korea presents the most immediate long-range missile threat to the United States. Obering told reporters Oct. 2 that the latest experiment “builds more and more confidence” that the system can provide protection.
The recent test varied little from the experiment last year. Lehner identified two differences to Arms Control Today. He pointed out that a ship-based Aegis radar tracked the target and that the interceptor had spent much more time than normal in the launch silo before being fired.
The Aegis radar operated in a so-called shadow mode, however, meaning the data it gathered was not used to help guide the interceptor. Aegis radars have operated in such a mode in previous GMD testing, but Lehner noted this was the first time one had participated since the MDA started launching target missiles from Kodiak. Prior to 2004, the Pentagon launched its targets from California toward the Marshall Islands, where the test interceptors had been based.
Test interceptors are typically installed in their underground launch silos roughly a month before use. But the September test interceptor had been in place since its intended use in a May 25 test that was aborted when the target missile veered off course. Lehner stated Oct. 15 that this longer wait displayed “operational realism” by demonstrating that an interceptor “can sit sealed up in the silo for months and then launch when needed.”
Some GMD critics, including Philip Coyle, a former director of the Pentagon’s weapons testing office, contend the MDA’s recent tests lack realism because they do not include countermeasures, such as decoys. Countermeasures are devices or techniques that a foe could employ to try and penetrate a missile defense.
Obering announced Oct. 2 that the agency would add some type of countermeasures to the GMD system’s next interceptor test, which might occur as soon as February. He refused to specify the countermeasures but noted they will be “similar” to ones previously used.
In tests conducted between October 1999 and December 2002, one to three balloon decoys were included as part of the target cluster with the mock warhead. At that time, some missile defense skeptics charged the decoys did not closely resemble the mock warhead, which made it easy to distinguish between them. Moreover, a decoy in one test apparently helped the EKV find its target. The EKV did not initially see the mock warhead, so it took aim at the decoy, which then happened to put the true target into the EKV’s line of sight. (See ACT, January/February 2000. )
The MDA suspended use of decoys when it switched flight testing to the Alaska-California corridor. Lehner Oct. 11 explained that one reason for excluding decoys was that an X-band radar located in the Marshall Islands was positioned to help discriminate various objects in the target cluster during the earlier tests but not the latter experiments.
Lehner stated, however, that the next test would involve the reintroduction of an X-band discrimination capability, specifically the Sea-Based X-band (SBX) Radar, which is an X-band radar mounted on a mobile, ocean-going oil rig platform. Like the Aegis radar, the SBX participated in a shadow mode in the last test.