PRELIMINARY STUDY OF THE LUNAR PHYSICAL LIBRATIONS BY VLBI OBSERVATIONS OF CHANG'E-3 LUNAR LANDER

The successful landing of the Chang'E-3 on the Moon opened up the window for observing the Moon with VLBI again. In this study, the method using VLBI observations of artificial sources on the lunar surface to estimate the Euler angles and lunar librations parameters is described and corresponding formulations are derived. VLBI observations of Chang'E-3 lunar lander were used to preliminarily estimate the Euler angles along with the lander position coordinates. The results showed that the Euler angles can be estimated along with the position coordinates of the lunar lander using the method described and applying the estimated Euler angle corrections could decrease the standard deviations of the lander position coordinates.