A CSP-Based Interactive Decision Aid for Space Mission Planning ⋆ Amedeo Cesta, Gabriella Cortellessa, Angelo Oddi, and Nicola Policella Planning & Scheduling Team Institute for Cognitive Science and Technology Viale K. Marx 15, I-00137 Rome, Italy {cesta,corte,oddi,policella}@ip.rm.cnr.it http://pst.ip.rm.cnr.it Abstract. This paper describes an innovative application of AI technol- ogy in the area of space mission planning. A system called Mexar has been developed to synthesize spacecraft operational commands for the memory dumping problem of the ESA mission called Mars Express. The approach implemented in Mexar is centered on constraint satisfac- tion techniques enhanced with flexible user interaction modalities. This paper describes the effort in developing a complete application that mod- els and solves a problem, and also offers functionalities to help users in interacting with different aspects of the problem. The paper surveys the design principles underlying the whole project and shows how different components contribute to the delivered system. 1 Introduction Mars Express is a space probe launched by the European Space Agency (ESA) on June 2, 2003 that will be orbiting around Mars starting from the beginning of 2004 for two years. Like all space missions, this program generates challenging problems for the AI planning and scheduling community. Mission planning is a term that defines a complex set of activities aimed at deciding the “day by day” tasks on a spacecraft and at figuring out if spacecraft safety is maintained and mission goals are met on a continuous base. Supporting a complete mission planning problem is a quite challenging goal involving several sub-activities. One of such sub-activities, the dumping of the on-board memories to the ground station is the topic of a study which the authors have conducted for Mars Express. A space system continuously produces a large amount of data which derives from the activities of its payloads (e.g. on-board scientific programs) and from on-board device monitoring and verification tasks (the so called housekeeping data). All these data, usually referred to as telemetry, are to be transferred to Earth during downlink connections. Mars Express is endowed with a single ⋆ This work describes results obtained in the framework of a research study conducted for the European Space Agency (ESA-ESOC) under contract No.14709/00/D/IM. A. Cappelli and F. Turini (Eds.): AI*IA 2003, LNAI 2829, pp. 511–522, 2003. c  Springer-Verlag Berlin Heidelberg 2003