Tucson-based Raytheon Missile Systems has received a $122.5 million contract modification from the U.S. Missile Defense Agency for continued development of the Standard Missile-3 Block IA and IB interceptors.

The SM-3 Block IA is deployed in support of the first phase of the administration's Phased Adaptive Approach for ballistic missile defense of Europe.

The SM-3 Block IB, still under development, has an enhanced kinetic warhead seeker, an advanced flight-control system and advanced signal processing. The SM-3 Block IB is on track for a 2015 deployment at sea and on land, Raytheon said.

Under the contract, Raytheon will provide SM-3 Block IA and IB design and engineering, in-service engineering support, production engineering, surveillance and flight test support, and transition to production.

The award follows a $241 million contract modification the MDA awarded to Raytheon earlier this month for work on the SM-3 Block IIA, which is being co-developed with Japan.

The SM-3 Block IIA features a larger rocket motor and an advanced kinetic warhead to defend a greater area.