A list of expected events during a spacecraft's flight and mission. It is compared with the spacecraft's real-time events to assure that the vehicle is functioning correctly. The times of events come from the spacecraft event file (SEF) drawn up by the spacecraft team. The list is called ‘integrated’ because it combines events on the spacecraft with those in the ground stations.

The ISOE is also used by ground stations, such as those of the deep-space network, to plan command uplinks, usually a week or more in advance of the events.