Free-Flight Experiment and Numerical Simulation for Cold Thruster Plume

An experiment, Astra-2, was performed at the space station Mir in 1995 ‐1996 to study its ambient atmosphere parameters. For far-e eld plume research, the equipment of Astra-2 included a small cold gas thruster using a marked gas, argon. The results of this research offer a good basis for validation of various numerical approaches for plume e ows, from simple engineering models to exact numerical approaches using a Navier ‐Stokes solver in the continuum regime and a direct simulation Monte-Carlo code in the near-continuum, transitional, and freemolecular regimes. A comparison of experimental and numerical results shows the necessity of accounting for argon condensation processes in the nozzle and in the vicinity near the nozzle.