Faults found in U.S. missile defense test
WASHINGTON — After the nation’s homeland missile defense system successfully intercepted a mock enemy warhead high above the Pacific on May 30, the director of the U.S. Missile Defense Agency said the test had been held under “very realistic” conditions, faithfully simulating an attack by North Korea.
“This is exactly the scenario we would expect to occur during an actual operational engagement,” Vice Adm. James D. Syring said at a news conference.
A week later, Syring told members of Congress: “The scenario that we conducted was actually an exact replica of the scenario that this country would face if North Korea were to fire a ballistic missile against the United States.”
In key aspects, however, the carefully scripted test posed much less of a challenge for U.S. missile defenses than would an actual attack, a Los Angeles Times/Tribune Washington Bureau investigation has found.
As a result, the successful intercept provides little if any confidence that the troubled Ground-based Midcourse Defense System, or GMD, would be able to thwart a sneak attack by North Korea, according to missile defense experts familiar with details of the test.
Their assessment carries added urgency in light of North Korea’s test this week of an intercontinental ballistic missile potentially capable of reaching Alaska. The missile flew farther than any previously tested by North Korea.
The May 30 test of U.S. missile defenses involved a target missile launched from the Marshall Islands in the western Pacific. The target was destroyed in space by an interceptor launched from Vandenberg Air Force Base in California.
In a departure from expected combat conditions, the target missile flew along a path where it could be tracked continuously by powerful U.S. radars that provide data to the GMD system, missile defense experts told The Times.
One of the radars, a giant, shipborne system whose home port is Pearl Harbor, was moved to a particular spot in the Pacific specifically for the test, U.S. officials said.
The result was that the radars had excellent lines of sight to follow the target beginning shortly after launch — an advantage U.S. forces likely would not have during an actual attack.
The test also strayed from operational realism in its use of decoys, the experts said. It is assumed that missiles launched by North Korea or another adversary would deploy decoys in an attempt to fool U.S. defenses. To stand a chance of thwarting an attack, the GMD system would need to distinguish between decoys and the target.
The decoys used during the May 30 test, however, did not resemble the target missile’s mock warhead, making it easier for the system to disregard them, the experts said.
In addition, the test was conducted during daylight hours, enhancing the system’s ability to find and track the target, and the personnel who conducted the exercise knew the target missile would be launched during a fixed time frame of several hours — another advantage that could not be expected in a real attack.
Finally, the target traveled at lower speeds than a North Korea-launched missile would need to reach the U.S. mainland.
“To claim that this is a realistic test of the ability to handle sophisticated threats is ridiculous,” said David K. Barton, a physicist and radar engineer who reviewed details of the May 30 exercise at The Times’ request.
Barton served on a National Academy of Sciences panel that studied the GMD system, and he has advised U.S. intelligence agencies.
Laura Grego, a physicist who examined the May 30 test as part of her research on U.S. missile defense capabilities for the Union of Concerned Scientists, said the advantageous conditions reduced the significance of the successful intercept.
“How does this test make you more confident that the system would perform against the North Korean threat?” Grego said. “It’s not a realistic attack scenario for Seattle, San Francisco, Los Angeles or any of the continental U.S.”
Barton and Grego both reviewed an unclassified Missile Defense Agency video that shows the exercise from launch to intercept and includes imagery from the interceptor’s onboard sensors.
Syring, who retired June 16 after nearly five years as the missile agency’s director, did not respond to a request for an interview.
An agency spokesman, Christopher Johnson, said in a statement that the May 30 exercise “was the most operationally realistic test we have conducted to date.” The distance flown by the mock enemy missile and the speed at which the GMD interceptor homed in on it were both greater than in previous tests, he said.