The U.S. Missile Defense Agency has awarded Tucson-based Raytheon Missile Systems a five-year, $925 million contract to continue development of a new ship-based missile interceptor with Japan.

The contract increases the total value of Raytheon's work on the Standard Missile-3 Block IIA missile to more than $1.5 billion, according to the Pentagon.

On track for deployment in 2018, the missile is the third in the SM-3 series of missiles. following the SM-3 Block IA and SM-3 Block IB.

The SM-3 Block IIA will have a larger, 21-inch second- and third-stage rocket motor and a larger, more capable kinetic, hit-to-kill warhead, the company said.

"The SM-3 IIA's larger rocket motors will allow for a greater defended area, which is an important factor when it comes to protecting both the U.S. and our NATO allies," Wes Kremer, vice president of the air and missile defense systems for Raytheon Missile Systems, said in prepared remarks.

SM-3 Block IA missiles are currently employed on Japan’s Kongo-class destroyers. Raytheon said it has delivered more than 130 SM-3 variants to the U.S. and Japanese navies.