This attribute allows you to set the step size used in defining a Launch or Hold segment of the MCS.
Astrogator <Satellite Object Path> SetValue <Attribute Path>.StepSize <Value> [{Unit}]
Specify the time interval between calculated ephemeris output points. Select from the standard options for a time unit of measure.
Astrogator */Satellite/Satellite1 SetValue MainSequence.SegmentList.Launch.StepSize 1 sec
STK Programming Interface 11.0.1