Ascent trajectory design for reusable launch vehicles

Ascent-trajectory optimization of reusable launch vehicles(RLV) is a difficult problem due to the complexity of many physical constraints and optimization cost surfaces.The ascent phase is divided into four segments for trajectory design,which are separation,lifting,power climb and un-power climb.The strategy for each segment trajectory is analyzed according to kinetic characters and the design parameters are studied.For trajectory optimization a heuristic technique based on a particle swarm optimization(PSO) algorithm is used.The highly constrained nonlinear trajectory planning problem is decomposed into design parameters search problems,the algorithm is able to generate a complete and feasible ascent trajectory,given the ascent conditions,values of constraint parameters and final conditions.Numerical simulation with a RLV model for ascent mission is presented to demonstrate the capability and effectiveness of the algorithm.