Tucson-based Raytheon Missile Systems has been awarded a $45.6 million contract for engineering and technical-support services for three ship-defense systems.

The contract is for work on the Phalanx Close-In Weapon System, a land-based version of the Phalanx and the SeaRAM, a small missile system based on the Phalanx.

The Phalanx is a rapid-fire gun system designed to track and destroy anti-ship missiles and other threats that have penetrated all other defenses. The SeaRAM Anti-ship Missile Defense System is based on the Phalanx carriage but fires small missiles used on Raytheon's Rolling Airframe Missile system.

Management and engineering for the Phalanx is based in Tucson. The system is made at Raytheon Missile Systems' plant in Louisville, Ky.