The U.S. Missile Defense Agency’s director is encouraging Japan to solidify plans to jointly produce the 21-in. SM-3 Block IIA ballistic missile killer to meet a tight fielding deadline in 2018.

Army Lt. Gen. Patrick O’Reilly, MDA director, says that preparations must be made for stateside industry to produce the U.S./Japanese SM-3 IIA if the partners are unable to come to an agreement on production plans for the Raytheon-led interceptor.

In a Jan. 3 letter to Nobushige Takamizawa, director general of policy for the Japanese Ministry of Defense, O’Reilly says that the “project is rapidly approaching key milestones at which production planning decisions will need to be made ... Absent a production agreement with the government of Japan, the United States will assume it will produce the missiles at Raytheon Missile Systems in the United States.” An MDA official verified the letter was sent to Japan.

The SM-3 IIA will provide greater range and more maneuverability than the SM-3 IAs now fielded and the SM-3 IB that is slated for fielding soon. These rely on a 14-in. booster.

Washington and Tokyo have an agreement on the development effort, but with fielding slated for 2018, the near-term goal is to hash out specific plans for missile production. A previous SM-3 program manager estimated that development of the IIA would cost about $2 billion between the partners.

Mitsubishi is developing the second- and third-stage rocket motors as well as the nosecone. Raytheon would be responsible for the payload and guidance kit, based on the development agreement.

Ideally, the partners eventually would produce the components that they design; This was always key for Japan’s joint development work and funding.

The first Block IIA flight test is slated for fiscal 2014, according to MDA spokesman Rick Lehner.

Should stateside production come to pass, O’Reilly says that both parties must “provide the necessary components to support each other’s production requirements. For example, the United States will require timely access to Japanese-designed SM-3 Block IIA components ... necessary to produce Japanese-designed components in the United States.” O’Reilly also emphasizes the importance of affordability in a missile “that avoids undue costs.”

Availability of missiles for other foreign partners is also a consideration, O’Reilly says. “Without assurance that the missiles will be available for third-party sale or transfer, we increase the risk of underestimating production capacity and increasing costs.”

The SM-3 Block IIA is being designed for use from the Navy’s MK41 ship-based vertical launch system, Navies capable of using this launch system would be candidates for international sales. The SM-3 Block IIA is also likely to be deployed on land as part of the European Phased Adaptive Approach architecture designed to protect much of Europe from an Iranian missile attack.