Lockheed Martin said the team it is leading in the development of the Mobile User Objective System (MUOS) successfully completed the system preliminary design review (PDR) with the U.S. Navy, a key milestone in the development of the new military satellite system. The PDR opens a key design and development phase for the space and ground segments to ensure the system will meet or exceed the Navy’s requirements for the next generation narrowband tactical satellite communications system. MUOS is expected to provide significantly improved and assured communications for U.S. mobile warfighters. The Navy awarded a $2.1 billion contract to Lockheed Martin to build the first two satellites and associated ground control elements, with options for three additional satellites.