This association indicates 2 or more scheduled contacts or tracking passes that make use of the same aperture. The multiple spacecraft making use of the same aperture do not necessarily have to have the same BOT or EOT times but there is at least some portion of the spacecraft tracking passes that are contemporaneous (i.e, the association is not used for completely disjoint tracking pass times for the multiple spacecraft). The DSN also adds a local extended parameter to indicate the priorities for the spacecraft in the association should antenna pointing need to be biased during the tracking pass if anomalous or emergency conditions arise for one of the spacecraft in the association.