The authors present the results of the numerical simulations of the thermo mechanical processes taking place inside the coaxialplasmagun and at the interaction between high speed gas jet and the dust deposited on the surfaces of the space vehicles. The purpose of the study on the use of coaxialplasma gun to clean the dust from the surfaces space vehicles in spatial missions to Mars, was to elucidate some aspects of the system's energy efficiency, thermal and mechanical effects of high-speed jet upon intersecting bodies and efficiency of the dust cleaning operation on the surfaces of space vehicles under atmospheric conditions of Mars. Numerical simulation of mechanical and thermal processes at the forming of the jet in gun, the interaction of the jet with the rarefied atmosphere of Mars and during the dust cleaning operations was conducted on a 3D physical model with a symmetrical plan which schematize real processes. The most important schematization refers to the shape and position of the plasma layer and uniform distribution of Lorentz forces on the unloading layer. The analysis of the state and of the movement of gas launched by the coaxialplasma gun had in attention both, the status parameters p, q, T and ρ and the jet velocity v. The plasma gun launches very short pulse type jets, with the output speed of the order of thousands of meters per second at temperatures of about 10,000 K. The mechanical and thermal effects produced by the gas jet on the intersected surfaces, were analysed by numerical simulations. There were no observed negative effects, the stresses and the temperatures induced in the structure have very low values. In the case of an extended cleaning action it can be produced the erosion of the attacked areas due to the sand particles movement with high speed. Numerical simulations showed, besides satisfactory efficiency of the coaxialplasmagun in the operation of removing the dust on surfaces of the spatial vehicle in space mission to Mars, some disadvantages of using this system, in the head of the list being the complexity and very low energy efficiency. © International Journal of Modern Manufacturing Technologies.