Research On Solar Sail Deep Space Exploration Orbit Control And Optimization Method

After entering the21st century, the field of deep space exploration has beentaken more and more attention by the human beings; countries around the worldhave introduced the development strategy and planning for future deep spaceexploration missions, striven to build a more completed space structure system,and implemented a series of scientific goals. Solar sail spacecraft with itscharacteristic of realizing flight control without reaction systems has high value inthe field of deep space probe, and even some space tasks can only be implementedby it. Because solar sail is that a kind of spacecraft realizing propulsion relaymainly on solar radiation pressure, and the solar radiation pressure is closelyrelated with the state of spacecraft orbit and attitude, orbit control and optimizationtechnology is therefore an important part within the whole system design for solarsail spacecraft.This paper is based on the initial design phase of space missions, takes thesolar sail spacecraft deep space probe orbit transfer task as the background, carriesout researches aiming at the orbit control and optimization method. Each phase ofthe transfer orbit is solved and analyzed by mathematical method, the suitability,stability and convergence of the orbit control and optimization method is discussedin this paper, and the connection conditions of various stages for transfer orbit arealso discussed, through improvement and integration to the existing mathematicalmethod constructs a set of orbit control and optimization method which can beapplied to the whole course of solar sail spacecraft explorations. In this paper theresearch content mainly includes the following several aspects:First, the time and coordinate system used in the process of solar sailspacecraft deep space exploration and transformation between each other are given,and the main operation stages of the orbit transfer are summarized in this paper.The model of solar radiation pressure is derived in detail, and also the maincharacteristic parameters involved in the transfer orbit design are given. The twobody orbit dynamics model of solar sail is established, regularization method fororbit dynamics model is also given. The mathematical description for orbit controlproblem based on solar sail deep space exploration orbit models is provided; thiswork will settle a theoretical foundation for follow-up study.Then, in the view of the solar sail spacecraft deep space probe orbit transferproblems, this paper presents a orbit control method which is based on localoptimal analytical solution, the method gives solar sail spacecraft attitudeinformation in real time in the form of closed loop analytic solutions, at the same time can realize joint control for each orbit element through weighted feedbackcontrol law. Aiming at the special requirements of solar sail spacecraft planetcaptured orbit, put forward a segmented control strategy with the capability ofdecoupling each orbit element, and verified through appropriate improvement, thelocal optimal analytical control law can be applied to various stages of transferorbit for solar sail explorations. In addition, also gives a kind of solar sailplanetary escaping orbit control law based on energy optimization, and its detailedderivation process is presented on the strength of the Pontryagin maximumprinciple.Due to the above solar sail orbit control method based on local optimalanalytical solutions has not set time of orbit transfer as its optimization objective,meanwhile, by analytical method, terminal state of the transfer orbit can not be setas a constraint, the transfer orbits given are only local optimal solutions. Moreover,owing to the terminal condition of a certain stage fails to meet the constraints oftransfer orbit; designers may unable to complete the design of whole coursetransfer orbit for solar sail spacecraft deep space probe. According to the aboveproblems, combining the local optimal solutions obtained by analytical control law,respectively employ the modified genetic algorithm based on multiparentalunimodal normal distribution crossover and the NSGA-Ⅱ multi-objectiveoptimization algorithm to get the hybrid optimization solutions of interstellartransfer orbit, the solutions of interstellar transfer orbit obtained by this methodcan be more close to global optimal, and can carry on the adjustment to terminalconstraints, thus applicable to solve connect problem in different stages of thetransfer orbit.Afterwards, this paper takes the Mercury detect mission as the background,based on the ideal solar sail propulsion model gives preliminary design method forMercury sun-synchronous orbit, and uses the non-ideal solar sail propulsion modelto verify the assumptions raised in the process of orbit preliminary design and theconditions of forming Mercury sun-synchronous orbit, furthermore, the orbitcharacteristics are analyzed, proved that the Mercury sun-synchronous polarelliptical orbit solved by the above method can make the spacecraft Automaticallysatisfy the synchronization in one Mercury’s orbital period.Finally, this paper makes improvement and integration for the solar sail orbitcontrol and optimization method, uses the missions of Earth to Sun Earth L1pointto Venus and Earth to Venus to Mercury as an example, and the whole journeyorbits of solar sail multi-mission deep space exploration are optimization designedand contrastive analyzed, at the same time, gives the treatment method for solarsail spacecraft attitude angular acceleration constraint, furthermore, the solar sailcapture conditions and characteristics for the whole journey orbits of deep space probe are studied, through the analysis, solar sail propulsion has obviousadvantages compared to traditional chemical propulsion, especially in the cases ofeach task needs to surround and detect rather than simply fly over, solar sailpropulsion has more obvious advantages.