GTOC9: Results from the National University of Defense Technology (team NUDT)

The ninth edition of the Global Trajectory Optimization Competition (GTOC) series was successfully organized in April 2017, wherein the competitors were called to design a series of missions able to remove a set of 123 orbiting debris pieces while minimizing the overall cumulative cost. A three-level optimization framework of the NUDT Team is presented and an improved Ant colony Optimization Algorithm, a hybrid encoding Genetic Algorithm and an improved Differential Evolution algorithm are applied to solve the complex problem, which combines the dynamic TSP, mixed-integer sequence optimization and perturbed trajectory rendezvous optimization. The result obtained during the competition ranked second in the eventual leaderboard.