Optimization of gimbaled thruster configurations for asteroid detumbling

Gimbaled thrusters for the purpose of asteroid detumbling hold the potential to vastly decrease detumbling time for asteroid redirection and asteroid mining missions. As interest in asteroid missions have increased, so have investigations into efficient detumbling methods. Controlling an asteroid’s attitude during a redirection or mining mission leads to much more controllable outcomes, and as such, developing a fast detumbling solution is advantageous. Much of the existing investigations have used fixed-orientation thrusters for optimizing asteroid detumbling, but these thrusters leave little room for error. The optimal solutions that are found for gimbaled thrusters are often uncontrollable for fixed-orientation thrusters, making gimbaled thrusters more versatile for detumbling purposes. This paper develops an approach that employs a genetic algorithm to find the optimal locations of gimbaled thrusters on asteroids for the purpose of rapid detumbling. A time-optimal controller was implemented to determine the orientation of the thrusters throughout the detumbling maneuver. This was investigated for four scenarios that may be the target of future asteroid detumbling missions—spheroid or elongated asteroids and slow or fast rotators. For each of these scenarios, the optimal landed configurations that maximize the torque generated to oppose the tumbling motion was first found, then detumbling was simulated for the best solution for each scenario. To enable comparison, detumbling simulations were also performed for each scenario with fixed-orientation thrusters with the same initial configuration. The results of the optimizations and detumbling simulations are discussed, and the viability of the method developed in this paper to optimize gimbaled thruster lander locations for asteroid detumbling is demonstrated.