Rapid planning for aerocapture trajectory via convex optimization

Aerocapture, which usually refers to delivering a vehicle from hyperbolic orbit to planetary orbit using the aerodynamic force, can potentially lower fuel consumption. By controlling the direction and magnitude of the aerodynamic force, the vehicle can be accurately transferred to the target orbit. This paper mainly focuses on developing a convex algorithm for the constrained trajectory planning of aerocapture. For nonlinear aerocapture problem, the main task is to convert this problem into a convex sub-problem, and then the solution of the original problem can be efficiently obtained by solving a sequence of such sub-problems with convex optimization. In order to formulate a highly constrained aerocapture trajectory-planning problem into a convex-form one, all non-convex items in aerocapture problem are turned into convex functions by successive linearization, variable equivalent replacement and control variable relaxation. The simulation results of the optimal aerocapture, represented by minimum impulse, flight time and heat load, indicate that the proposed method is highly efficient and can be potentially applied for on-board trajectory planning method.