Safety And Stability Analysis On Formation Of Lunar Satellites With Large Elliptical Orbit

The formation of satellites can accurately control the attitude between the satellites and maintain the stability of the formation orbit.It is of great practical significance to the exploration project.At present,the domestic and foreign formation research mainly focuses on the elliptical orbits or near-circular orbits in the near-Earth.There are few studies on the lunar orbit,and there is still a considerable gap in the research on the lunar satellites formation with large elliptical orbit as well.Due to the uneven mass of the moon,the ball model cannot be simply approximated.If the high-order perturbation of the gravitational field of the moon is neglected,the formation control based on the near-earth orbital kinematics model may result in adverse consequences such as collisions among the satellites.Therefore,it is necessary to re-analyze the influence of the security of the separation in terms of satellite formations,various errors on the formation,and the influence of the perturbation terms of other lunar gravitational fields on the stability of the satellite formation configuration.The main research contents of the paper are as follows:In this paper,we establish a satellites formation movement model including perturbation of the moon's aspherical gravitational perturbation,three-body gravitational perturbation of the sun,solar photodynamic perturbation,and perturbation of the moon's physical balance.The error propagation mechanism of the model is also analyzed to find out the sensitivity of the model to different errors.A suitable safety evaluation standard is proposed to evaluate the safety of different separation methods for the lunar satellite formation with large elliptical orbit,and based on the risk assessment function,a suitable separation strategy is proposed as well.In this paper,numerical simulations are used to obtain the most easily colliding point data after different separation pulses are applied to different separation points.After calculating the collision probability of the most easily colliding point,the simulation parameters are integrated through the risk assessment function to evaluate the safety of different separation methods.Finally,according to the established safety evaluation criteria,a separation strategy for large elliptical satellites formation in lunar orbit is found.In this paper,we also analyze the dynamic characteristics of satellite formations under fine spatial perturbation,and then formulate a reasonable flow of the formation configuration design,and design several formations configurations that satisfy stability and passive safety under long-periodic perturbation conditions.The influence of fine spatial perturbation on the dynamic characteristics of the large elliptical orbit under the lunar environment is studied.By studying the response of the configuration to different fine spatial perturbations,the performance of this configuration is verified in the end.