Guidance systems of Minuteman intercontinental ballistic missiles will continue to be maintained by Boeing under a new U.S. Air Force contract.

The award from the U.S. Air Force Nuclear Weapon Center at Hill Air Force Base, Utah, is an indefinite-delivery/indefinite-quantity contract with a potential maximum value of $466.5 million.

Boeing says it has provided Minuteman ICBM repair services on an exclusive basis since 1996 and the new award extends its services through 2021.

"Boeing has decades of experience maintaining these intricately designed missile guidance sets," said Ellen Power, director, Boeing Guidance Repair Center. "Precision, quality and reliability are critical requirements for every missile guidance set we repair and return to the Air Force."

Minuteman is the land-based component of the U.S. nuclear triad of nuclear weapons, which includes submarine-launched Trident missiles and bomber aircraft.

Each Minuteman missile carries up to three nuclear warheads.

Boeing did not disclose other details of the contract.