Aimed at the problems of ensuring the approaching safety of net-based space robotic system and reducing fuel consumption by trajectories plannings during proximity maneuver to the target,according to the passive safety concept,the multi-pulses flying-by approaching trajectory is designed for thruster with the consideration of collision avoidance under relative measurement failures,and the trajectory enables the robotic system to perform the capture operation when passing by the target.Based on the relative dynamics of the spacecrafts,the flying-by approaching trajectory planning model is established with safety inequality constraints,and the solution is achieved by applying linear programming method with velocity increment optimization.Finally,the rationality and trajectory safety are verified by a series of simulations.