APPLICATION OF NUMERICAL MULTIZONE APPROACH TO THE STUDY OF SATELLITETHRUSTER PLUMES

The work performed during the implementation phase of an integrated se t of computer codes developed to study plume flows generated from sate llite main engines and thrusters is described. The major aim of the wo rk was to achieve the capability to cover the complete cycle of gasdyn amics analyses required to assess the impact that plume impingement ef fects may have on the satellite and on its sensitive payload or instru mentation. A simplified configuration of the European Space Agency's s atellite for the X-Ray Multi-Mirror Mission was considered as a test c ase for the purpose of implementing and testing the computer codes. In this regard, the issue of major concern consisted of the estimation o f the thrust loss produced by plume impingement during the injection m aneuver of the satellite into a higher perigee orbit. Results obtained by Navier-Stokes, direct simulation Monte Carlo, and test particle Mo nte Carlo calculations are described, and the flow patterns settling i n during thruster firing in the regions of interest are discussed. The major finding of the study mas the detection of a serious incompatibi lity between the preliminary assumed design orientation of the satelli te thrusters and the flight dynamics requirements imposed by the satel lite mission. In conclusion, the study fully provides evidence of the critical role and usefulness of this kind of numerical analyses in pro viding answers contributing to the optimization of successful satellit e design.