WASHINGTON — A U.S.-Japanese industrial team has finalized the design of the largest planned member of the Standard Missile (SM)-3 interceptor family and is on track to begin flight testing in 2015, according to a senior executive with Raytheon, which is leading the U.S. side of the effort.

The SM-3 Block 2A interceptor passed its critical design review in mid-October, according to Wes Kremer, vice president of Air and Missile Defense Systems for Raytheon Missile Systems. Initial flight testing could be followed by an intercept attempt in 2016 with full-rate production starting the year after that, he said.

The latest schedule represents a slight delay from expectations in 2010, when the company said flight testing would start in 2014.

The new interceptor, being jointly developed with Japan under an agreement signed in 2006, is a more capable version of the Raytheon-built SM-3 Block 1A and 1B, the munitions for the sea-based Aegis Ballistic Missile Defense system. Designed for deployment on ships or on land, the Block 2A features second and third stages that are wider, at 53 centimeters, than those on the current SM-3 variants, giving it the range and velocity needed to engage intermediate-range ballistic missiles. 

As such, the SM-3 Block 2A is a key part of the European Phased Adaptive Approach (EPAA) for defending NATO allies, which is centered around the Lockheed Martin-developed Aegis Weapon System, the SM-3, and a network of ground-, air- and space-based sensors. The EPAA currently relies on sea-based SM-3 Block 1A interceptors, but subsequent phases will see variants, including the Block 2A, deployed on land under an effort dubbed Aegis Ashore. 

Speaking Oct. 30 at the American Institute of Aeronautics and Astronautics’ missile defense conference in Poland, Kremer said deployment of the SM-3 Block 2A in Romania and Poland remains on schedule to begin in 2018. Just two days earlier, the U.S. Missile Defense Agency (MDA) broke ground the Romanian site, which will be outfitted, at least initially, with SM-3 Block 1B interceptors.

“When Phase 2 of EPAA is completed here in the 2015 timeframe, Europe will be safer, U.S. forces will be better protected, and the NATO alliance will be stronger,” James Miller, U.S undersecretary of defense for policy, said during the groundbreaking ceremony. “Moreover, our efforts here in Romania serve as a precursor for the Phase 3 site in Poland.”

Tucson, Ariz.-based Raytheon Missile Systems is under contract to build 22 Block 2A interceptors for developmental testing.

Japan has committed $1 billion for its portion of SM-3 Block 2A development-phase work, with Tokyo-based Mitsubishi Heavy Industries as prime contractor. Mitsubishi is responsible for the interceptor’s second- and third-stage motors and nose cone.

The total anticipated U.S. cost for Block 2A development is $2.3 billion including $1.5 billion from 2012 through 2018, according to budget documents. The MDA’s 2013 contribution to co-development effort was nearly $421 million, and the agency is seeking $308 million in 2014.

Another key feature of the SM-3 Block 2A is a bigger, more-maneuverable kill vehicle, which is being developed by Raytheon. Subcontractor Aerojet Rocketdyne of Sacramento, Calif., on Aug. 30 announced that it had completed the critical design review of the kill vehicle’s throttling divert and attitude control motor, which allows the kinetic warhead to maneuver in space toward its target. 

Aerojet previously announced that it had conducted the second hot fire test of a fully integrated prototype of the propulsion system. “The fact that we had two successful hot fire tests in two months demonstrates the maturity of the design,” Dave Parker, executive director for SM-3 programs for Aerojet Rocketdyne’s Missile Defense and Strategic Systems Business Unit, said in a prepared statement Aug. 29.

Twitter: @Gruss_SN

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...