Hazardous asteroid deflection based on “space billiard” mode: Mission analysis and trajectory design

Defense against potentially hazardous asteroids is crucial to human civilization. An asteroid projectile can be redirected to intercept hazardous asteroids by employing gravity assist from the Earth or Moon, thereby effectively altering their trajectory. Such an asteroid defense mode is referred to as “space billiard.” Current investigations regarding mission planning and trajectory design for this mode are either incomplete or contain imperfect perspectives. This article proposes a comprehensive mission planning from spacecraft departure to the impact of a hazardous asteroid with an asteroid projectile. This involves selecting an asteroid projectile, determining the maneuver time, and optimizing the low-thrust trajectory. The particle swarm optimization algorithm for the Lambert problem is introduced to search for the maneuver time, and low-thrust optimization is performed to design the transfer trajectory of the spacecraft. A collision model based on NASA’s DART mission is used to analyze the feasibility of this approach. A classic example where this approach is adopted is for analyzing the hazardous asteroid Apophis. Based on this analysis, an asteroid projectile named 2015 VC2 is selected for simulation. The complete trajectories of the spacecraft and asteroid projectile are simulated, and the feasibility of the scheme is verified. This approach may be a feasible option for defending against hazardous asteroids.