A STUDY OF EFFECTS OF THE GAS-SURFACE INTERACTION ON SPINNING CONVEX BODIES WITH APPLICATION TO SATELLITE EXPERIMENTS

: In rarefied gas flow problems there are two effects which influence the flow; (1) collisions of gas molecules with other gas molecules, and (2) collisions of gas molecules with solid surfaces (the gas-surface interaction). This study deals with free molecular flow in which the effect of gas-gas collision can be neglected and the gas-surface interaction has the dominate influence on the flow. The results of this study have application to satellites since free molecular flow conditions occur at orbital altitudes above 120km. Knowledge of the gas-surface interaction is required in order to determine the aerodynamic properties of satellites. At satellite velocities (7-8km/sec) the interaction of neutral atmospheric gas molecules with the satellite surface occurs at energies in the 1 to 10 ev range. It is just this energy range which has not been satisfactorily duplicated in the laboratory; therefore, at present, laboratory gas-surface interaction data can not be applied directly to the determination of the aerodynamics properties of satellites. It is proposed in this study that satellite experiments be performed to obtain the needed information from measurements of the aerodynamics properties of satellites. In order to interpret the satellite data, a generalized gas-surface interaction model was developed and used in the analysis of this study.