The output of the mission planning software is an observing schedule for one or more revolutions. Any schedule is frozen at least three days prior to the start of that particular revolution. According to that schedule, observations are carried out by the staff of the Science Operations Centre and the Spacecraft Control Centre.
The staff of the Science Operations Centre will conduct the observations, monitor the instrument performance and state of health and assess the scientific quality of the data. Some observations will require real-time intervention by the staff. In these cases, room will be left in the schedule in form of a `time-slot' that permits to execute the corresponding procedure.