The COSMO-SkyMed Seconda Generazione System simulation study cannot be performed by means of conventional SW COTS because of its complexity. Thus a specific Mission Simulator has been designed with the main objective of supporting a range of activities starting from the design phase, through the verification and validation phase up to the end-to-end tests of the commissioning phase. The COSMO-SkyMed Seconda Generazione Mission Simulator (CSG-MS) is a run-time software application which is able to configure, plan and simulate the Mission with the capability to replicate the end-to-end mission “behaviour” in response to a given “scenario” defined by a specific mission configuration together with the “user requests handbook”.