太阳同步轨道二维变姿态空间相机的外热流计算

为了得到准确的二维变姿态空间相机外热流数据，提出了一种在J2000坐标系下进行二维变姿态空间相机的外热流算法。首先，在J2000坐标系下确定了相机的位置、太阳的位置及其辐射强度；其次，根据空间相机的视轴始终指向太阳的工作特点及太阳的位置，计算出其在极端情况下的二维姿态角；然后，根据得到的姿态角计算出姿态变换矩阵。最后，利用Matlab编程计算出一个轨道周期内的不变姿态以及二维变姿态条件下的复杂外热流。该方法计算得到的不变姿态外热流与I-deas/TMG软件得到的结果能够很好地吻合。与姿态不变的相机相比，相机二维姿态的变化会导致其外热流发生较大的变化，尤其是入光口所在的-Y面，其太阳直射热流的波动范围为0~1 394 W/m2。得到的姿态角为热仿真模型姿态的调整提供了重要参考。由变姿态外热流数据可以看出，-Z面的外热流最小，其最大平均外热流小于4 W/m2。另外X面和+Y面的外热流也较小，X面最大平均外热流小于80 W/m2，+Y面最大平均外热流小于110 W/m2。在实际应用中，由于卫星平台的遮挡，X面和+Y面的外热流会更小，因此可以将-Z面，X面和+Y面作为散热面，为热设计工作提拱了很好的指导。

Calculation of external heat fluxes on space camera with two-dimensional changing attitudes in sun-synchronous orbit

In order to get accurate data of external heat fluxes on space camera with two-dimensional changing attitudes, a method was proposed to calculate the external heat fluxes of space camera with two-dimensional changing attitudes in J2000 coordinate system. First, in J2000 coordinate system positions of space camera, position and radiation intensity of sun were calculated. Second, according to the working characteristics of the space camera whose visual axis always points to the sun and the position of the sun, its two-dimensional attitude angles were calculated under extreme conditions. Then, based on the obtained attitude angles, the attitude transformation matrix was calculated. Finally, in one orbital period external heat fluxes of unchanging attitude and two-dimensional changing attitudes were calculated with Matlab programming. The external heat fluxes of this paper were in good agreement with I-deas/TMG software. Compared with the unchanging attitude camera, external heat fluxes of the two-dimensional changing atitudes camera will have a great change, especially for the -Y surface where optical entrance is located. The solar radiation heat fluxes fluctuation range of -Y surface is 0-1 394 W/m2. The obtained attitude angles provide an important reference for the adjustment of the attitude for the thermal simulation model. According to the data of the external heat flux with changing attitudes, it can be seen that the external heat fluxes of the -Z surface is smallest, and the maximum average period external heat fluxes of -Z surface is less than 4 W/m2. In addition, the external heat fluxes of the X surfaces and +Y surface are smaller, and the maximum average period external heat fluxes of X surfaces are less than 80 W/m2, and the maximum average period external heat fluxes of +Y surface are less than 110 W/m2. In practical application, the external heat fluxes of X surfaces and +Y surface will be smaller due to the obstruction of the satellite platform. Therefore, the -Z surface, X surfaces and +Y surface can be used as heat dissipation surfaces, which provides a good guide for thermal design work.