Rapid Prototyping of Planning & Scheduling Tools

The Advanced Planning and Scheduling Initiative, or APSI, is an ESA programme to design and implement an Artificial Intelligence (AI) software infrastructure for planning and scheduling that can generically support different types and classes of space mission operations. The goal of the APSI is twofold: (1)~creating a software framework to improve the cost-effectiveness and flexibility of mission planning support tool development; (2)~bridging the gap between AI planning and scheduling technology and the world of space mission planning. A key aspect of the success of this project is the presence of a flexible timeline representation module that allows to exploit alternatives in the modeling of mission features. This paper shows an example of such a flexibility by using a real problem in the space realm - the HERSCHEL Science Long Term Planning process.