An Ad-hoc Planner for the Mars Express Mission

Complete planning and scheduling of all spacecraft operations is a challenging area with the remote agent experiment at Deep Space 1 being a pioneering system. Still the complete approach is rare in practice. For example, in the Mars Express (MEX) mission, planning and scheduling techniques are used to solve some subproblems namely scheduling command upload and data download. In this paper we describe an approach to generate a complete schedule of the spacecraft that includes planning and scheduling of science, command uplink, data downlink, maintenance, and pointing operations. The proposed solving approach was designed to plan operations on the Mars Express (MEX) mission and it was motivated by the MEX challenge at the Fourth International Competition on Knowledge Engineering for Planning and Scheduling. The method is based on incremental addition of operations to a partial schedule and modifying the time allocation of already scheduled operations to fit the newly added operation. Despite its simplicity, the method seems to perform very well on experimental data, though a deeper evaluation with real data is still necessary. The paper briefly describes the problem solved, the integrated planning and scheduling algorithm, and the initial experimental results.