A target missile failure marred a planned Terminal High Altitude Area Defense (THAAD) missile interceptor test, the second time in more than six years that a target missile has malfunctioned, according to the Missile Defense Agency (MDA).

The target Hera missile, equipped with surplus motors, “experienced a malfunction shortly after it was launched [Sept. 13] and was destroyed by range safety officials at White Sands Missile Range, N.M.,” according to MDA.

At least the interceptor missile wasn’t wasted in the test.

“The THAAD interceptor missile was not launched and will be used for a future test,” according to an MDA statement.

Cause of the failure isn’t yet known, and won’t be anytime soon, according to MDA.

“Per standard procedure, an extensive review is taking place to determine the cause of the target failure, and this will take several weeks,” the agency reported.

The MDA said its targets program has been “a model of success,” with 86 target missiles launched since January 2000.

During this period there has been only one other failure, and this occurred in 2001 during a target-only test due to a range communication issue, the MDA noted.

Different targets are used for different interceptor systems.

The Hera target missile was assembled by Coleman Research of Orlando, Fla., a unit of L-3 Communications [LLL], and consisted of surplus second and third stage rocket motors previously used for the Air Force Minuteman II strategic missile program. Those missiles have been retired from active service.

Despite the glitch, MDA still supports using surplus motors.

“It is extremely cost-effective to use surplus and retired rocket motors rather than buying new motors,” according to the agency. “Even though the rocket motors used for the most recent Hera launch were approximately 40 years old, they remain extremely reliable and have an excellent record of performance.”

The agency also expressed continued confidence in its target-missiles contractors, including Northrop Grumman Corp. [NOC].

“The target missile failure has no impact on MDA’s level of confidence regarding Coleman Research, Northrop Grumman or any of the other companies that make up the MDA targets team,’ the missile shield agency stated.

“The companies have all provided reliable and effective rocket motors for missile defense tests and will continue to do so.”