The Pentagon’s multi-billion-dollar missile defense shield has failed for the third time in nearly five years to intercept a target missile, marking the latest disappointment in a string of lackluster flight test results since the last successful intercept test in December 2008.

During a July 5 trial, the Ground-Based Interceptor was launched from Vandenberg AFB, Calif., against a target lofted from the Kwajalein Atoll in the Pacific. The U.S. Missile Defense Agency is mum about the sequence of events other than a brief acknowledgment that no intercept took place.

Spokesman Rick Lehner was unable to say whether the interceptor, which includes an Orbital Sciences booster, successfully executed its anticipated flight path and deployed the Exoatmospheric Kill Vehicle (EKV), a Raytheon system designed to destroy a warhead by using a direct hit. Further, he would not say whether the test included countermeasures from the target that are designed to confuse the radar and optical sensors used by the missile defense system to hone in on a mark. He said Congress and the State Department must first be briefed on the results.

The failure is an embarrassment for U.S. Defense Secretary Chuck Hagel, who hastily added this test of the Ground-Based Midcourse Defense (GMD) system to the schedule in response to North Korea’s third test of a nuclear weapon in February. The trial was intended to “increase warfighter confidence,” MDA Director Vice Adm. James Syring told senators in May. It was supposed to showcase the ability of Washington to down an incoming ballistic missile in an effort to deter the nuclear ICBM ambitions of Kim Jong-un, the new, saber-rattling North Korean leader.

Last week’s trial included the baseline GMD kill vehicle, though it was upgraded with some reliability enhancements since the December 2008 test. “We have made numerous improvements to the [EKV] fleet through refurbishments since the last successful [EKV] flight test in 2008, and this test will demonstrate the reliability of those refurbished GBIs,” Syring told senators. It was thought to be a fairly routine test to simply remind North Korea and Iran that the U.S. can knock incoming warheads out of the sky.

The failure is also the first major, public hurdle for Syring, who took over MDA in November. It was also the first intercept attempt for GMD since Boeing won a $3.5 billion contract in late 2011 to manage sustainment of the program. Boeing won the program through an aggressive pricing approach; compared to its legacy GMD contract, the cost plummeted about 35%. Support for tests is part of this contract.

After the last successful test of this kill vehicle in December 2008, the program turned its attention to fielding a new kill vehicle, called the Capability Enhancement II system. CE II’s design specifications are classified, but it was developed by Raytheon to better discriminate warheads from countermeasures and increase the probability of a single-shot kill. The CE II failed to intercept a target in what was described by an MDA official as the most challenging missile defense test to date in January 2010. Officials have said they have a fix in hand; the next test of it is slated for year’s end, though that could slip into next year now with the recent failure.

Lehner said a failure review board has been assembled to assess what went wrong in the July 5 test.