Study On The Cislunar Transfer Trajectory Of The Lunar Probe

The cislunar transfer trajectory is the key technique of the lunar probe engineering. The studies on Earth-to-Moon transfer trajectories are relatively more mature, outweighing the researches on Moon-to-Earth transfer trajectories. Since the Moon-to-Earth transfer trajectories are different from Earth-to-Moon transfer trajectories, the profound studies on Moon-to-Earth transfer trajectories become worthy. In addition, the new ways to solve the problems and the essential laws about the special Earth-to-Moon transfer trajectory need to be provided. The studies above can consummate the theoretical system and the research techniques about the cisluar transfer trajectories design.The problems about cisluar transfer trajectories design of the lunar probe are studied in the paper, in which the return orbit from Moon to Earth of the lunar probe is emphasized. Firstly, the characters of Moon-to-Earth transfer trajectories are analyzed, and then the return orbit design is researched systematically. Secondly, the TT&C analysis is researched and an example for midcourse correction of the Moon-to-Earth transfer trajectory is given. Thirdly, kinematical constraint characters of the launch window for Earth-to-Moon transfer trajectories based on the high elliptical parking orbit are analyzed, and a design method for the Earth-to-Moon transfer trajectory based on the high elliptical parking orbit is proposed. Finally, the new way to achieve geostationary satellite and reserved satellite using lunar swingby technique is provided.Characters of Moon-to-Earth transfer trajectories are analyzed, which indicates that the two-body hypothesis is not acceptable for Moon-to-Earth transfer trajectories. And so a series of analytical models are founded upon the idealized double two-body hypotheses, based on which some key qualitative conclusions can be drawn; for example, the Moon-centered part of Moon-to-Earth transfer trajectories which can be used for the engineering must be hyperbolic. The output point must be located in the eastern hemisphere of lunar sphere of influence. The initial transfer velocity and the perigee velocity of the Moon-to-Earth transfer trajectory are affected significantly by the longitude of the output point. It only requires minimum energy to achieve the Moon-to-Earth transfer trajectory when the longitude of the output point is 80 degrees east.Based on the characters of Moon-to-Earth transfer trajectories, a fast searching design method is achieved for the return orbit of the lunar probe under the idealized double two-body hypotheses. A searching algorithm based on the dichotomy is put forward. This method is an algebraic method that doesn't need trajectory integral. The time will be reduced greatly, and the orbit solution satisfying many objective constraints can be obtained quickly. The output parameters gotten from preliminary design can be used as the initial value for precise design.The precise design for the Moon-to-Earth return orbit of the lunar probe is researched. First of all, the dynamic equations for the Moon-to-Earth return orbit are founded. Then several perturbations which affect the Moon-to-Earth transfer trajectory are analyzed, and the results show that the Moon gravity perturbation and the Sun gravity perturbation have more significant influence on the Moon-to-Earth transfer trajectory. Through introducing the appropriate optimization searching algorithm called Differential Corrector, the precise design is achieved for the return orbit which includes multiple searching variables and multiple objective functions. Combined with the precise design and the preliminary design, the integrated design scheme for the Moon-to-Earth return orbit of the lunar probe is established. According to the Moon-to-Earth transfer trajectory designed, an example for midcourse correction is given. And then the influence on the correction impulses of velocity because of the error of launch window and the time of correction is obtained through the analysis on the example.For the Moon-to-Earth return orbit, the bound and characters of the TT&C task are analyzed and the appropriate TT&C network is selected. Combined with the simulation example, the variation law of the measurement elements of the return orbit is given and the percentage of coverage of tracking measurement for TT&C network is analyzed. The result indicates that it can satisfy the requirements of the engineering. The Moon-to-Earth transfer trajectory determination is studied using USB (Unified S-Band) and VLBI (Very Long Baseline Interferometry) data.Kinematical constraint characters of the launch window for Earth-to-Moon transfer trajectories which are based on the high elliptical parking orbit are analyzed. Then a design method for Earth-to-Moon transfer trajectory based on the high elliptical parking orbit is provided. In the condition of the fixed flying time, rendezvous between the probe and Moon in a sidereal month based on the high elliptical parking orbit is studied. The results show that there are only two opportunities to launch in a sidereal month for CZ-3A launch vehicle in our country, and the declination of the Moon is 0 degree at the rendezvous time. According to the results, the initial value of the injection time can be selected when the launch window is designed. For the two opportunities in the sidereal month, through modifying the initial velocity of the transfer trajectory, one transfer trajectory solution or several solutions which satisfy the longitude and latitude constraints of the injection point can be found. The injection window is proved by a zero window based on the high elliptical parking orbit, and there may be a new injection opportunity after one round rotation of the Earth. For the launch window based on the high elliptical parking orbit, some variation laws and conclusions of several key parameters of the transfer trajectory after modifying the injection velocity are concluded.A new method to achieve geostationary satellite and reserved satellite using lunar swingby technique is researched at last. The step by step searching method which is used to obtain the accurate cislunar transfer trajectory is provided. The method is fast and effective, which can provide references to the trajectory design for the probe, especially for the deep-space probe.