The downlink process is defined as the portion of the system which begins with the production of a data stream by either platform or payload and ends with the placement of properly catalogued processed data into an archive. The downlink process begins at the sensor, where commands generated by the uplink process are received. More general ancillary data which may apply to several sensors are downlinked separately and joined to the user data as a final step in the data production process. Commands produced in the sequence design process define whether the data handler is to pass the data directly to the telecommunications subsystem for immediate downlink or to record them in an on-board data storage device for later transmission. The capability to manipulate the data and build interface files to offline or commercial software such as spreadsheets or database programs is also valuable.