In the present study, a two-dimensional numerical simulation was carried out for binary mixture. The influence of micro gravity vibration or acceleration on board Iinternational Space Station and FOTON-M3, influence of different cavities size as well as the effect of the sign of the Soret coefficient (fluid flow, heat and mass transfer and concentration) in the solvent were investigated in detail. It must be noted that based on previous experiences with this investigation using the same mixture and cavity by Saghir and Parsa  the CFD modeling was performed up to 8500s. By this time the quasi-steady state has been reached in most of the mixtures. This thermodiffusion experiment using binary mixture at low pressure condition on the ISS cases shows higher error value for concentration profile at the end of the experiment; compare to FOTON-M3 satellite. However, it should be mentioned that all the errors are significant and more than 25 percent; thus, this kind of investigation should be considered for experiments on all of space vehicles.