I. Introduction
The concept of model-based SoSE is evolving. This paper is focused on clarifying what model-based SoSE is, and how it is different from model-based Systems Engineering (SE). Literature indicates that model-based SoSE is based upon model-based systems engineering (MBSE). This paper argues that this approach is insufficient and that many additional factors need to be considered when applying modeling and simulation to SoSE. The authors therefore propose the term M&SBSoSE to describe the critical role of simulation when managing system of systems, as illustrated in this paper.