Mission Planning Of The Close-range Rendezvous For The Low Earth Orbit Spacecraft

With the rapid development of aerospace technology,spacecraft are playing an irreplaceable role in various fields.Spacecraft on-orbit service technology has gradually attracted attention because of its ability to effectively extend the service life of spacecraft,reduce the cost of a single launch,repair disabled spacecraft,remove space debris on orbit,and greatly increase the utilization of outer space.In order to achieve the most ideal service effect while minimizing the cost of a single on-orbit service,the service spacecraft needs to adjust their real-time position and implement on-orbit services for the target spacecraft based on different orbital maneuvering strategies according to the different needs of different on-orbit service missions and the real-time position of the service spacecrafts and the target spacecrafts.This paper focuses on the problem of close distance rendezvous between the on-orbit service spacecraft and the target spacecraft under complex perturbation conditions and conducts research on the solution of orbital maneuvering strategies,considering the load observation abilities and the limitations of the platform’s maneuverability.The main research content is as follows:To solve the orbit transfer strategy under complex perturbation conditions,the orbit dynamics modeling of the spacecraft is carried out at first with the spacecraft’s perturbation force analyzed.An ideal two-body model,a low-precision orbital dynamics model considering the main perturbation forces and a high-precision orbital dynamics model considering all perturbation factors are established.They are respectively used for iterative initial valve solution,fast iterative optimization of orbit transfer strategy and high-precision orbit propagation in order to save computing resources on the premise of the error requirements.A one-maneuvering-approach transfer strategy under a three-step solution framework is proposed for the spacecraft rendezvous problem with small phase angle difference,short distance and no time constraints.Considering the different mission requirements of the target spacecraft with different orbital planes,the approach transfer process is divided into coplanar approach and non-coplanar approach according to the orbital inclination difference between the service spacecraft and the target spacecraft.The former considers the solar illumination angle to determine the rendezvous time,so that the service spacecraft can obtain better target observation conditions.The latter considers the relative position of the orbit surface of the target spacecraft and the service spacecraft to determine the rendezvous time,so that the service spacecraft can obtain a longer target observation window.In order to deal with the influence of complex perturbation conditions on orbit transfer strategy and reduce fuel consumption as much as possible,a three-step solution framework of "two body initial value determination +low precision iterative optimization + high precision strategy solution" is proposed.In this framework,the analytical solution of Hohmann transfer is used as the initial iteration value firstly,and then the low-precision orbital dynamics model is used to iteratively optimize the dwelling time of service spacecraft in each orbit,the Lambert transfer strategy is used to complete the actual transfer at last.The mission is completed by one maneuvering and the effectiveness and feasibility of the strategy is verified by the mathematical simulation.A solution method for two maneuvering large-scale transfer strategies under a threestep solution framework is proposed for the spacecraft rendezvous problem with large phase angle difference,long distance and short time constraints.The whole process of large-scale transfer is described,and then the three-step solution framework is followed but targeted changes are made.Th e height of transition orbit is estimated to determine the initial value.In order to give consideration to both fuel consumption and accuracy,the "Hohmann + Lambert" two maneuvers large-scale transfer strategy is adopted,and a complete strategy solution method is given.Finally,numerical simulation and comparative analysis of simulation results under different conditions verify the effectiveness and feasibility of large-scale transfer.