低地球轨道空间环境下航天器表面原子氧通量密度和积分通量分布的数值模拟(英文)

Numerical simulation of atomic oxygen flux and fluence distribution on spacecraft surface in low earth orbit space environment

基于蒙特卡罗方法和区域分解法,建立低地球轨道空间环境航天器表面原子氧通量密度和积分通量的数学模型。模型考虑了航天器表面几何构型、原子氧数密度和分析热运动、地球自转对航天器速度的影响以及轨道运行参数。通量密度分布的求解是通过其微分方程的对于独立变量分子运动速度和与表面速度矢量合成的积分得到,积分通量是通过沿轨道时间积分来实现。与此同时,得到了沿入射攻角变化原子氧分布的最大值和最小值。计算结果表明:通量分布伴随入射攻角增大而急剧下降,在迎风面达到最大值,背风面最小值。入射攻角是影响分布计算结果的重要因素。计算误差与NASA-LDEF飞行试验实验结果吻合较好。

A mathematical model of atomic oxygen flux and fluence distribution is built for spacecraft surface in low earth orbit space environment (LEO), based on Monte Carlo ray tracing and domain decomposition methods (MCRT-DD). Spacecraft geometry, number density and molecular thermal motion of atomic oxygen, spacecraft velocity affected by atmosphere co-rotation and orbit propagation parameters are considered in the model. The differential equation for flux is integrated with respect to molecular speed and direction of the molecular velocity vector relative to the surface. Fluence along the propagation path is an integrated flux with respect to time. Meanwhile, those of maximum and minimum values and variations with different incidence angles are calculated. Results show that the distribution takes a decreasing tendency markedly with the increasing incidence angle; at the same time, the flux density reaches the maximum value in a positive incidence angle and the minimum value in a leeward incidence angle and the incidence angle is an important factor to affect the distribution and the calculation error, as agrees well with the Long Duration Exposure Facility of National Aeronautics and Space Administration (LDEF-NASA) flight experiment data.