ALENIA has recently built a model with EcosimPro that simulates the real discharge of gases produced inside the cabin of the Automated Transportation Vehicle by a dedicated Gas Delivery System. The analysis, performed in nominal and contingency scenarios, has confirmed the validity of EcosimPro as a powerful and flexible tool for solving complex problems with high non-linearity indices. The ATV is scheduled to be launched in 2006 and forms part of the International Space Station project.