A kinetic impact strategy for deflecting an asteroid to form a gravity tractor system with a potentially hazardous asteroid

Near-Earth asteroids pose an enormous threat to Earth. Removing them effectively from risk orbits is a crucial issue. To improve the deflection efficiency, we propose a method to control an intermediate asteroid as a gravity tractor to change the orbit of potentially hazardous asteroid. A multiple kinetic impact method is applied to an intermediate asteroid to change its orbit toward the potentially hazardous asteroid. The goal of multiple kinetic impacts is to control the intermediate asteroid to form a gravity tractor system with the potentially hazardous asteroid. First, we chose an asteroid that requires smaller transfer velocity increments as an intermediate asteroid. Then, we design the orbit of the gravity tractor system and use a multi-objective harris hawk optimization algorithm to optimize the kinetic impact mission. Finally, the effects of direct transfer model, multi-pulse transfer model, and gravity assist transfer model are investigated respectively. We compare the three transfer models and obtain a suitable kinetic impact deflection scheme. The results show that the proposed method can effectively deflect the potentially hazardous asteroid. Using an asteroid as a gravity tractor can greatly increase the deflection distance. Deflection distances can be increased from hundreds of kilometers to fractions of an AU.