Mission scheduling for spacecraft: the diaries of T-SCHED

Describes the scheduling system T-SCHED, developed to automatically generate mission command sequences for the UOSAT-II satellite. At present the schedules are generated by hand, which is a slow and potentially error-prone activity. While the exercise has shown the author´s techniques to be successful with UOSAT-II, further investigations are required of applicability to more complex satellites such as ERS-1, before a complete picture can be gained. The paper provides a brief background to UOSAT-II, describes the design of the scheduling system and the representation of the constraints within it, discusses a typical scheduling problem and test results. Finally it suggests possible directions for future work