During the ballistic phase of a cryogenic upper stage, attitude and orbit control are usually performed by a cold gas thruster system. Since the thruster inlet pressure is driven by the propellant tank ullage conditions, a sufficient pressure regeneration rate has to be assured to compensate the pressure decrease during thruster activation. The coupling between the thruster activation sequence, stage kinematics, and thermal environment is essential for the performance prediction of cold gas systems. An iteration loop using a statistical model considering the thruster activation sequence is applied. For detailed final analysis, an EcosimPro model is used, including three-dimensional (3D) CFD (computational fluid dynamics) sloshing analysis and all relevant boundary conditions.