Variable durative actions based mission planning for the approach phase of small body explorer

Autonomous planning technology for the deep space exploration mission has achieved wide attention recently. Traditional mission planning for deep space explorer uses activity with fixed duration. But during the actual mission operating of deep space explorer, activity's execution time varies from the goal of mission based on current situation and capacity. Specifically, the mission for the approach phase of small body raised demand for faster and higher ability of operation because of its own characteristics, such as coupling among missions, numerous subsystems, complicated constraints, high requirements of real time, etc. In order to design reasonable and feasible sequences in limited time to realize the system goals, this paper analyzes the constraints and requirements of autonomous planning system during the approach phase of small body based on Planning Domain Definition Language (PDDL). And a method of mission planning modeling is proposed to solve the variable time duration problem of activity during the approach phase of small body explorer. In the simulation results, the duration of charging and communication can be determined by actual time based on the requirements of resource constraints. This method can roundly and flexibly represent the variable durative actions and meet the demand of autonomous planning for the approach phase of small body for deep space explorer.