The Affect of Physical Libration of Moon on Lunar Obiter

摘要

Lunar physical libration, which is the true swing of lunar equator in the space, not only brings the different definition of the selenocentric equatorial coordinate system, but also alters the lunar gravitational field in the space coordinate system and affects the orbiting motion of lunar orbiter (or called lunar satellites) correspondingly. This kind of affection is very similar with that of the precession and nutation on the earth satellites. This paper will adopt the method which resemble the one used in the effect of precession and nutation on the earth satellites, discuss the affect of physical libration of moon on the selenocentric equatorial system and the motion of lunar satellite. Based on the comparison of the physical libration in DE405 and the analytical expression, the corresponding variation of gravitational potential and the solution of additional perturbation due to the change of coordinate system are given, which indicate orbital variation clearly, and the comparison with corresponding numerical solution shows this discussion is significative from the aspects of both quality and quantity.