Lecture Description
This lecture covers selected topics in astrodynamics, with a particular focus on the Earth–Moon system. It examines the rotation of these two celestial bodies and the determination of their respective gravitational fields.
To study rotational motion, the Earth and the Moon are treated as extended bodies within the framework of the general three-body problem Sun–Earth–Moon. Special attention is given to the motion of the Earth’s rotation axis in space (precession and nutation) and on the Earth’s surface (polar motion), as well as to the optical and physical libration of the Moon and the precessional motion of the Moon’s rotational pole. The relevant equations are derived using either a rigid-body model or an elastic Earth model.
In the determination of gravitational fields, the objective is to infer the coefficients of a mathematical model from observational data. In modern astrodynamics, two main types of measurements are distinguished: precise measurements of satellite orbits or difference between satellite orbits, and in-situ measurements of the second derivatives of the gravitational potential from satellites (gradiometry). Both approaches are discussed in the lecture. In addition, current results from AIUB research are presented, along with recent efforts to determine the Moon’s gravitational field with significantly improved accuracy using astrodynamical methods.
The lecture is primarily intended for students majoring in astronomy within the Bachelor’s programme in Physics/Astronomy, but it is also open to other interested students. Knowledge of the material covered in Astrodynamics I is required.
