This attribute determines if the magnitude field of spherical elements will accept negative values.
Astrogator <Satellite Object Path> SetValue <Astrogator Object Path>.AllowNegativeSphericalMagnitude <Value>
The value is a boolean. Set this attribute to true to allow negative values for spherical magnitude. This option may be useful with targeting problems if you are not certain of the direction of the maneuver. When a negative value is used for magnitude, the delta-V is in the opposite direction of the specified azimuth and elevation. The actual azimuth will be 180 degrees from the specified azimuth, and the actual elevation will the negative of the specified elevation.
Astrogator */Satellite/Satellite1 SetValue MainSequence.SegmentList.Maneuver.ImpulsiveMnvr.AllowNegativeSphericalMagnitude true
STK Programming Interface 11.0.1