Study Of Secondary Electron Emission And Spacecraft Surface Charging

Spacecraft charging effects can be divided into two parts:surface charging and internal charging. And it is one of the major incentives for Spacecraft anomalies and failures, which is caused by the space environment. Surface charging is a space environment effect, which is first discovered. However, secondary electron emission is a very important factor that influences surface charging. Therefore, the research mainly focuses on the spacecraft surface charging, and involves space environment, spacecraft materials, secondary electron emission and numerical calculation of surface charging potential.In the beginning of the paper, the concepts of spacecraft charging and discharging, the basic principle, domestic and foreign development and related achievements were introduced. Chapter II described the relevant knowledge of space environment, spacecraft materials and secondary electron emission. And we focus on the performance requirements of spacecraft surface materials in space environment and the main influencing factors to secondary electron yield of surface materials. Under the influence of various factors, the secondary electron yield fluctuates in a wide range. So, it makes sense to deduce the formula of secondary electron yield.Then, based on dominant physical processes, the relevant theoretical models and the experimental data, when primary electrons enter the emitter vertically in the incident energy range of2-10keV and10-100keV respectively, several universal formulas for expressing the secondary electron yield of metals were deduced. And based on the relationship between oblique incidence and vertical incidence, in combination with the radio and the expression of backscattering coefficient, we deduced several universal formulas for expressing the secondary electron yield of metals when primary electrons enter the emitter at θ in the incident energy range of2-10keV and10-102keV respectively. The results show that these formulas are successful.Finally, by using the more accurate formulas we deduced above and the local current balance model, the surface charging potentials of shaded-surfaces of a spacecraft were calculated for different surface materials and shapes, in MATLAB. According to the numerical results and secondary electron yield, we get that spacecraft surface charging potentials have a great relationship with maximum secondary electron yield, the atomic number of surface materials and secondary electron yield caused by incident ions. And it has a certain reference value for the selection and design technique of surface materials.