上面级在发射轨道的辐射外热流分析

研究发射轨道的外热流是进行火箭上面级和卫星热控设计的基础。文章给出了基于一组轨道和姿态参数的太阳矢量与地球矢量的计算方法。针对圆柱外形的上面级，分析了其发射轨道外热流的变化规律，利用该计算方法计算了太阳矢量，而太阳矢量在长时间滑行段相对固定，太阳矢量和受晒因子随发射时间而发生大幅度的变化，使得外热流工况变得非常复杂。通过对太阳定姿且绕箭体纵轴慢旋，可改善火箭上面级的飞行热环境，简化卫星和上面级的热控系统设计。

Analysis of external radiation heat flux for upper stage on launch orbit

The analysis of the external heat flux on launch orbit is extremely important for the thermal design of both upper stage and satellites. This paper proposes a method for the calculation of the vector to the Sun and the vector to the Earth based on a group of orbital and attitude parameters. The external heat flux for the cylindrical upper stage is analyzed. It is indicated that the solar illumination is the dominant external heat flux on the launch orbit. The vector to the Sun is relatively invariable during the long coast phase, while both the vector to the Sun and the percent time in the sunlight vary greatly with the launch time, which complicates the extreme cases. The sun-orientation and a slow spin around the longitudinal axis is recommended for the improvement of the thermal environment and the simplification of the thermal control system for satellites and upper stage.