# Dynamic Behavior and Libration Control of an Electrodynamic Tether System for Space Debris Capture
## 5 Conclusions  
This study investigates the dynamic responses and libration angle control capabilities of an EDT system for space debris capture. By employing the ANCF, we develop a three-dimensional model that accurately captures the complex behavior of the EDT system, particularly the effects of tether deformation and electrodynamic forces. Additionally, the study explores the electrodynamic characteristics of the system and examines the feasibility of on-off switch control for stabilizing the libration angles induced by debris capture. The findings demonstrate that the EDT system effectively manages libration angles across varying debris masses and velocities, highlighting its potential for enhancing the efficiency and repeatability of space debris removal missions.  
The key conclusions are as follows: (1) The developed three-dimensional EDT system model, based on ANCF, accurately represents the intricate dynamics of the system, emphasizing the crucial role of tether deformation and electrodynamic forces. (2) The current generated in the EDT system is directly influenced by tether length and diameter, with longer and thicker tethers producing higher currents, underscoring the importance of these parameters in system performance. (3) Tether length significantly affects both current generation and Lorentz force distribution, where an increase in length leads to higher current and a more extensive force distribution, thereby enhancing the total Lorentz force. (4) Tether diameter plays a key role in optimizing system efficiency, as a larger diameter increases the electron collection capability, resulting in higher current generation.  
Figure 12: Variation of the libration angle of the EDT system for different masses and velocities of space debris: (**a**) Case 1, (**b**) Case 2, and (**c**) Case 3.  
(5) In the absence of electrodynamic forces, the libration angle remains unchanged after debris capture. However, applying the Lorentz force through the EDT system and implementing on-off switch control effectively dampens and stabilizes libration angles across various debris masses and velocities, demonstrating the feasibility of this approach for mission stability.  
These findings contribute to a deeper understanding of flexible tether dynamics in EDT systems and provide valuable insights for optimizing space debris removal strategies using electrodynamic forces.  
Conceptualization, J.C. and W.J.; methodology: W.J.; software programming, W.J. and Y.Y.; validation, W.J. and M.G.; formal analysis, J.C. and W.J.; investigation, Y.Y. and M.G.; resources, [PERSON]; data curation, W.J. and Y.Y.; writing--original draft preparation, [PERSON]; writing--review and editing, [PERSON] and J.C.; visualization, [PERSON] and M.G.; supervision, [PERSON]; project administration, [PERSON]; funding acquisition, [PERSON] All authors have read and agreed to the published version of the manuscript.  
This work was supported by a grant from the National Research Foundation of Korea (NRF), funded by the Korean Government (MEST) (NRF-2021R1A2C2007979).  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.