About BAE Systems Space & Mission Systems BAE Systems, Inc. is the U.S. subsidiary of BAE Systems plc, an international defense, aerospace and security company which delivers a full range of products and services for air, land and naval forces, as well as advanced electronics, security, information technology solutions and customer support services. In partnership with the Subcontract Manager (SMS' empowered official for the subcontract), act as the principal interface with the subcontractor on all subcontract related subjects and perform as a liaison between subcontractor, Program, and other stakeholders as needed.