Hagel acknowledged a problem with the guidance system of missile interceptors and said further testing would occur this year.

CNN: U.S. to beef up missile defense against North Korea, Iran

He acknowledged a problem with the guidance system of missile interceptors and said further testing would occur this year.

CNN: U.S. to beef up missile defense against North Korea, Iran

Lockheed Martin received a contract in 2007 to extend the life of the missiles until at least 2040, with additional contracts doled out to upgrade the guidance system and refurbish the nuclear warheads the missile carries.

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