Dynamics Of Rotating Triangle-like Tethered Satellite Formation Near The Libration Point

Tethered satellite formation flying is a new area of research in the21st century and many scholars have done some research work about it. By comparing with the traditional satellite, the tethered satellite formation system has unique advantages, such as low-cost, low energy consumption, high performance, high flexibility, etc. Through its own rotation, triangular tethered satellite system can keep the tether tension and stability of the system which can greatly save the fuel consumption of the system compared with the traditional tethered satellite system. Some basic studies and experiments have been done about the triangular tethered satellite formation in abroad. This indicates that it has practical significance to investigate this system.Firstly, we introduce the basic concepts, characteristics and the progress of the research of the tethered satellite formation in this dissertation. The significance to study the triangular tethered satellite has also been discussed. Then, the basic theories and concepts which will be used during the process of modeling are introduced in detail, such as three-body problem, libration points, differential correction method, etc. Finally, we study the stability of the rotating triangular tethered satellite formation system near the L2libration point through presenting a reasonably and effectively dynamical model of the system.It is assumed that the system only moves in the plane of the Sun-Earth system, only the gravity is taken into consideration, and the tethers are always tension and without considering their masses for simplicity sake. Based on these assumptions, the kinetic and potential energy of the system near the L2libration point are derived. A set of high nonlinear coupling equations of the attitude motion and orbit motion are obtained by substituting the kinetic and potential energy into the Lagrange equation. In order to study the stability of the rotating triangular tethered satellite formation system, the effects of the orbital attitude, the tether length and the rotating rate on the stability of the system are considered respectively. We chose two sets of the initial values of the Lyapunov plane periodic orbit which are corrected by the differential correction method. Then, triangular tethered satellite formation system with different lengths of each side is simulated respectively. Different rotating rates are taken into account to analyze the stability of the system. The results of simulating demonstrate that the stability of the system is not the same in different orbits, i.e. the orbit altitude has some effects on the stability of the system. The length of tether almost does not affect the trajectory of the system center of mass. In addition, the rotation rate has a great influence on the stability of the system, i.e. the greater the rotation rate, the better the stability of the system. In fact, the larger the rotation rate is, the greater the system’s centrifugal force is, and the system’s stability is better as well.