Haibin Shang

Solution space research for interplanetary trajectory

Purpose – The purpose of this paper is to present a solution space searching method to study the initial design of interplanetary low thrust gravity assist trajectory.Design/methodology/approach – For reducing the complexity and nonlinearity of the initial design problem, a sixth degree inverse polynomial shape based approach is brought. Then some improvements are provided for solving the parameters in the shape function and a quasi‐lambert solver is brought through the shape based method, the thrust profile can be generated under the given time of flight, boundary states including positions and velocities for low thrust phase. Combining gravity assist model, the problem is summarized and an improved pruning technique is used for searching the feasible solution space for low thrust gravity assist trajectory.Findings – Using the solution space searching method, the feasible solution region would be generated under the given mission condition. The treatment about gravity assist demonstrates more accurate th...

Transfer trajectory design about doubly synchronous binary asteroid system

To obtain the high-resolution image or detect the inner structure of both bodies of binary asteroid systems, the spacecraft should be given the ability to transfer between the surfaces of two components. This paper contributes to develop a robust method to design transfer trajectory in the doubly synchronous binary system based on the libration point orbits and their invariant manifolds. After selecting the surfaces of two bodies as Poincare sections, the L1 and L2/3 manifolds can be patched together to construct the equatorial and spatial transfer trajectory. The heteroclinic link of the L2 and L3 manifolds are studied to find an alternative transfer trajectory sets by applying the tiny velocity increments. Further, the effect of the solar radiation pressure on the transfer manifold tube is discussed. The results indicate that it is suitable to transfer for a spacecraft when the sun line is perpendicular to the line connecting two bodies because the single-trip transfer tubes are generated.

Low thrust gravity assist trajectory optimization based on hybrid method

The application and advantage of low thrust propulsion system has been validated in practical mission launch even though the trajectory design difficulty is increased. The trajectory optimization problem brought by the use of low thrust propulsion in conjunction with gravity assist is researched. This paper proposes a hybrid technique for solving the strong nonlinear and multiple constraints optimal control problem using a hybrid technique. First, a nonlinear programming problem is proposed by abandoning the terminal constraints brought by Pontryagin maximum principle and treating costates as optimization variables; Then an adjoint control transformation is used for converting costate variables to other variables partially which possess actual bounds and physical meaning; Finally, differential evolution algorithm is employed for searching the initial values of nonlinear programming problem for local accurate optimization. Related low thrust gravity assist trajectories to outer planets by various gravity assists are designed for demonstrating the effectiveness of the proposed hybrid technique.