Current written system specifications have a high degree of uncertainty which causes specifications to be changed because they are incorrect, incomplete or do not possess the degree of rigor to make them precise. Even when generated by modeling methods such as UML/SySML or standards such as DoDAF, these functional specifications still lack any validation with respect to architecture, mission, and scenario impacts. The lack of consideration of these aspects creates design errors are usually exposed during the test and integration phases where the expense is greater to correct than in the early conceptual design phase. This paper will introduce the concept of Validated Executable Specifications (VES) that will enable Model Based Systems Engineering (MBSE) to validate early in the design process to reduce risk and save costs in a System of System (SoS) model.