Several crucial developments in orbital mechanics are obtained through the method of averaging, which is equivalent to integrating only the dominant harmonics of the Fourier series of the dynamics. Frequency analysis of the trajectory expressed in orbital elements facilitates an in-depth understanding of Earth satellite dynamics, and facilitates the interpretation of numerical results from special perturbations within the theoretical framework of celestial mechanics. In this work, we examine recent Two-Line Element series for LAGEOS-1 in the frequency domain, highlighting the presence of short-periodic terms that are likely introduced in the generation of TLEs from observations. We also propose employing well-established methods from signal processing, such as spectrograms, to examine the evolution of dissipative systems such as satellites in LEO
