U.S. Air Force airborne weapons experts are ordering several hundred of the nation's most sophisticated radar-guided, air-to-air missiles for U.S. military allies under terms of a $634.2 million contract. The Raytheon Co. Missile Systems segment in Tucson, Ariz., will build Lot 31 production of the AIM-120 Advanced Medium Range Air to Air Missile (AMRAAM) for allied militaries. AMRAAM is one of the world's most advanced all-weather, all-environment medium range air-to-air missiles. The system is an active radar-guided intercept missile with inherent electronic protection capabilities for air-to-air applications against massed penetration aircraft and is designed to replace the AIM-7 Sparrow air-to-air missile. This contract involves foreign military sales (FMS) AMRAAM missiles to Japan, Korea, Morocco, Poland, Indonesia, Romania, Spain, Turkey, Bahrain, and Qatar. The AMRAAM missile has air-to-air and surface-launch versions. In the air-to-air role, the weapon's advanced active guidance section provides the aircrew find targets quickly in challenging environments, Raytheon officials say.