This attribute specifies the 'hold on pad' (pre-launch) time interval of the Launch segment. The vehicle remains at the launch position until the beginning of the launch epoch.
Astrogator <Satellite Object Path> SetValue <Astrogator Object Path>.Hold <Value> <Unit>
Specify the amount of time before the spacecraft's launch that it will be created in the scenario. Choose from the standard options for a time unit of measure.
Astrogator */Satellite/Satellite1 SetValue MainSequence.SegmentList.Launch.Launch.Hold 10 min
STK Programming Interface 11.0.1