地球静止轨道变姿态空间相机的外热流计算

Computation of external heat fluxes on space camera with attitude change in geostationary orbit

  • 摘要: 为了获取中高轨道变姿态空间相机准确的外热流数据,提出一种求解其变姿态外热流的方法。以地球静止轨道空间相机为例,首先确定卫星-太阳-地球三者之间的相对位置关系;然后,根据相机对日成像的工作任务确定其不同时刻的姿态;最后,根据相机姿态变化后的环境映射面以及直接积分法获得的辐射角系数计算相机各表面的瞬时外热流。计算结果表明,在相同轨道条件下,相机由于在轨姿态变化导致其接受到的外热流总和比姿态恒定的相机有所减少,其中春分日总热流减少372.5 W/m2,冬至日总热流减少771.5 W/m2。入光口所在的+X面外热流增大了2倍左右,该面进出地球阴影区时外热流在0~1 378 W/m2之间剧烈波动。计算结果可指导相机热设计,该方法同样适用于多维变姿态航天器的外热流计算。

     

    Abstract: In order to obtain accurate external heat fluxes of space camera with attitude change that works in the medium and high earth orbit, a method to calculate its external heat fluxes was proposed. Taking a geostationary space camera as an example, the relative position among the satellite, the sun and the earth was confirmed firstly. And then the camera's attitude was calculated according to its sun imaging mission. Finally, the instantaneous external heat fluxes on space camera were calculated based on its environmental mapping planes after changing attitude and the radiation view factors given by direct integration method. The result shows that under the same orbit condition, the total external heat fluxes of space camera with attitude change decreases dramatically by 372.5 W/m2 and 771.5 W/m2, in March equinox and December solstice respectively. The external heat fluxes on the +X direction plane where optical entrance is located increases by 2 times, and the external heat fluxes on this plane fluctuates wildly from 0 W/m2 to 1 378 W/m2. What's more, these computational results provide a good guidance for camera's thermal design, and this method can as well be applied to calculate the external heat fluxes of spacecraft with multi-dimensional attitude change.

     

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