Penumbra lunar eclipse observations reveal anomalous thermal performance of Lunakhod 2 reflectors  

作　　者：Tian-Quan Gao Cai-Shi Zhang Hong-Chao Zhao Li-Xiang Zhou Xian-Lin Wu Hsienchi Yeh Ming Li 高添泉;张才士;赵宏超;周立祥;吴先霖;叶贤基;李明(MOE Key Laboratory of TianQin Mission,TianQin Research Center for Gravitational Physics&School of Physics and Astronomy,Frontiers Science Center for TianQin,CNSA Research Center for Gravitational Waves,Sun Yat-sen University(Zhuhai Campus),Zhuhai 519082,China)

机构地区：[1]MOE Key Laboratory of TianQin Mission,TianQin Research Center for Gravitational Physics&School of Physics and Astronomy,Frontiers Science Center for TianQin,CNSA Research Center for Gravitational Waves,Sun Yat-sen University(Zhuhai Campus),Zhuhai 519082,China

出　　处：《Chinese Physics B》2022年第5期212-218,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.12033009)。

摘　　要：As the signal reflected by the corner-cube reflector arrays is very weak and easily submerged during the full moon,we analyze the influence of the thermal effect of corner-cube reflector arrays on the intensity of lunar laser ranging echo.Laser ranging measurements during the penumbra lunar eclipse verify suspected thermal deformation in the Lunakhod 2 reflectors.Signal levels vary over two orders of magnitude as the penumbra eclipse progresses.This can be explained by the change in the dihedral angle of the corner-cube reflectors caused by the temperature.The results show that when the dihedral angle errors reach 1,the energy is reduced by 100 times compared with the ideal corner-cube reflector.In the experiment,our findings suggest that when the corner-cube reflector arrays enter the penumbra of the earth,the effective echo signal level which reaches 0.18 photons/s far exceeds the historical level of the full moon.However,11 minutes after the penumbra lunar eclipse,the effective echo rate of Lunakhod 2 will drop two orders of magnitude.The mechanism can explain the acute signal deficit observed at full moon.

关 键 词：lunar laser ranging corner-cube reflector arrays dihedral angle errors penumbra lunar eclipse 

分 类 号：TN249[电子电信—物理电子学] P125.12[天文地球—天体测量]