The Automatic Determination and Dissemination of Just Updated Steering Terms, better known as the ADDJUST file, is being loaded into the Delta IV Heavy rocket’s Inertial Navigation and Control Assembly (INCA) flight computer by the flight control operator here at the Launch Control Center. This is the planned steering parameters for the INCA to use based on today’s upper level wind conditions.
A series of weather balloons has been launched throughout the countdown from the Range weather station at Cape Canaveral to collect measurements of wind speeds and directions to determine if conditions aloft violate the controllability or structural loads on the rocket during ascent. The balloon data was transmitted to ULA engineers in Denver to select a steering profile that minimizes launch vehicle responses.