Site problems Tools Tools to are used to perform essential tasks or generate products. For the Space and Missile Systems Center (SMC) program environment, we might consider activities by program phase then associate those tools needed or beneficial to use. For example, during the concept definition phase, an interest would be in modeling the missions the system is going to support. Mission models and simulations are developed to run case scenarios in both threat environments and non-hostile operating environments. During the concept phase the concept and operational architecture definition is important. Architecture tools are used to define the architectures in conjunction with an assortment of modeling and analysis tools to assess and down-select the best conceptual choices. As systems definition and development commences, the continued use of the modeling and architecture tools used in the previous phase significantly add to the modeling tool suite to support analyses and conclude the technical/design solutions. During the systems definition and development, more emphasis is placed on the requirements development, requirements and design analysis and validations, cost modeling and analysis, and program management tools. Following deployment of a system, tools are used to perform and manage operations and maintenance. In addition, many of the tools used during development are also used to support major modifications and upgrades. Examples of tools that are candidates for continual use following deployment include: Diminishing Manufacturing Sources (DMS), configuration control/management, and possibly some of the Modeling and Simulation (M&S) and analytical tools that would support system modifications. Defense Modeling & Simulation  High Level Architecture (HLA) Concept of System Architecture Requirements Change Management Program Management