Orbiting object - set angle opposite to the direction of motion of the main object

I have my player ship pinned to a Drag and Drop object with a floating shield. When the ship moves, I'd like for the shield to be angled opposite to the direction of movement. I guess in short I'm having trouble determining the angle of movement of an object that's being moved via touch.

Opposite direction have angle difference 180 degree. You coudn't be wrong using addition or subtraction by 180 degree, either works. Incorporate Anglelerp if easing is mandatory.