Tiangong-1’s accelerated self-spin before reentry
Tiangong-1’s accelerated self-spin before reentry
复制标题
天宫一号重返大气层前加速自转
DOI：
10.1186/s40623-019-0996-8
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Deng Hua-Rong
中科院分区：
文献类型：
--
作者：
Lin Hou-Yuan;Zhu Ting-Lei;Liang Zhi-Peng;Zhao Chang-Yin;Wei Dong;Zhang Wei;Han Xing-Wei;Zhang Hai-Feng;Wei Zhi-Bin;Li Yu-Qiang;Xiong Jian-Ning;Zhan Jin-Wei;Zhang Chen;Ping Yi-Ding;Song Qing-Li;Zhang Hai-Tao;Deng Hua-Rong
空间碎片的自转运动受环境因素的影响，其检测和研究是一个热门话题。然而，由于缺乏观测数据，无法在极低轨道区域进行相关研究。在这里，我们填补空白，呈现天宫一号在重返大气层前5个月的旋转演化。天宫一号在观测过程中相对稳定，但由于重力梯度力矩的作用，其角动量偏离最大主惯性轴，绕轨道面法向进动，角度为2 3.1∘±2.5∘。需要与角动量和进动速度之间的关系保持一致，才能得到自转速度的解，从而发现自转速度会增加。这一结果不能用以前开发的任何扭矩模型来解释。为此，提出了一个大气密度梯度力矩(ADGT)模型，该模型在卫星尺度上考虑了大气密度随轨道高度变化而产生的力矩，以解释极低轨道物体的旋转加速机制。数值结果表明，ADGT模型具有不可忽略的解释加速效应的能力，但不能完全描述加速效应。天宫一号的旋转演化数据可以通过解决以前模型中遗漏的次要因素，为气动模型的改进提供重要的依据。
The detection and study of the rotational motion of space debris, which is affected by environmental factors, is a popular topic. However, relevant research in extremely low-orbit regions cannot be conducted due to a lack of observational data. Here, we fill in the gaps to present the rotational evolution of Tiangong-1 in the 5 months prior to reentry. Derived from the changes in the relative distance of its two corner cube reflectors from satellite laser ranging data, the angular momentum of Tiangong-1, which is relatively stable during observation, deviates from its maximum principal axis of inertia and precesses around the normal direction of the orbital plane due to gravity gradient torque at an angle of $$23.1^\circ \pm\,2.5^\circ$$23.1∘±2.5∘. Requiring consistency with the relationship between the angular momentum and precession rate leads to a solution for the rotation rate, which is thus found to increase. This result cannot be explained by any previously developed torque models. Hence, an atmospheric density gradient torque (ADGT) model that considers the torque generated by the change in atmospheric density with orbital altitude at the satellite scale is proposed to explain the rotational acceleration mechanism of extremely low-orbit objects. The numerical results show that the ADGT model provides a non-negligible ability to explain, but cannot fully describe, the acceleration effect. The data on the rotational evolution of Tiangong-1 can provide an important basis for aerodynamic model improvement by addressing minor factors omitted in previous models.