Researches On The Range Safety Of Booster Based On Flight Mode Prediction

At present,the space launch missions become more and more intensive,and the economy and society of shooting range develop continually.Under this situation,in order to protect the safety of people's life and property,and ensure the successful developing of organization and logistics services around launch tasks,also for saving time and money on searching the remains of reentry boosters,the issues on the impact point prediction and the detailed design of the safe area are urgent to be solved.For predicting the impact point precisely,the key is to understand the kinematics mechanism during the booster's reentry region.The booster reentry without any control force,so that it has very complicated attitude motions.And different characteristics of attitude motions can lead to different form of reentry trajectory and different impact point.This paper put the attitude kinematics mechanism as the entry point,propose a method for impact point prediction base on flight mode analysis.Firstly,this paper introduce the engineering prediction methods of aerodynamic characteristics based on the viscous circumferential flow and slender-body theory,solving the problem of rapid calculation for booster aerodynamic parameters around width range of angle of attack.The 6DOF simulation model is developed,based on the model,researches on standard trajectory and deviation trajectory is done,as well the influence of parameter to the form of trajectory.Further more,this paper researches on attitude dynamics analysis.For the sake of the pitch channel,studying the dynamic stability and obtaining the domains of attraction distributions of attractors.In terms of the three channels,the classic Euler angles are introduced based on the complete dynamics model which reduces the complexities of the dynamics.Nonlinear analysis methods are introduced to research the attitude dynamics of the reentry booster.The trim states are computed by some evolutionary algorithm.The local stability around the trim states is simulated by the first theorem of Lyapunov.Simulation results indicate that the reentry-booster has groups of trim states,and the angular motions will diverge to the equilibrium points or limit cycles under different initial flight conditions.Otherwise,the simulation analyses that draw support from the MATCONT software are applied for limit point bifurcation and Hopf bifurcation.Finally,an impact point prediction method of booster based on flight mode analysis is proposed.By comparing with the MTKL method and the traditional extreme drag coefficient method,it suggests the reasonability of the new method.