Since the early 2000' years, the CubeSats have been growing and getting more and more "space" in the Space industry. Their short development schedule, low cost equipment and piggyback launches create a new way to access the space, provide new services and enable the development of new technologies for processes and applications. That is the case of the Verification and Validation of these missions. As they are cheaper to launch than traditional space missions, CubeSats win by numbers. With more than 1000 CubeSats launched they still achieve less than 50% rate of successful missions and that is caused mainly by poor V&V processes. Model Based approaches are trying to help in these problems as they help software developers along the last years. As complex systems, space products can be helped by the introduction of models in different levels. Operational goals can be achieved by modeling behavioral scenarios and simulating operational procedures. Here, we present a possible modeling solution using a tool that integrates the functionalities of FSM and Statechartes, the ATOM SysVAP (System for Validation of Finite Automatons and Execution Plans). With this tool we are able to model the behaviour of a space mission, from its top level (i.e. system and segments) to its low level (subsystems) and simulate their interactions (operation). With the help of Lua Programming Language, it is possible to generate analysis files, specific scenarios and control internal variables.