# Difference between orbital mechanics and astrodynamics ?

Hello all.
The title of this thread sums up my question - what is the difference between orbital mechanics and astrodynamics ? Or is there a difference at all ?

I have sometimes seen different uses of the terms, for example, on many sites I see " astrodynamics or orbital mechanics is .... " , while on others I see " astrodynamics studies motion of spacecraft ... ". Often terms are used interchangeably, but sometimes some distinctions are made. For example as mentioned, astrodynamics is sometimes mentioned along with spacecraft, while orbital mechanics is with celestial bodies.

Does anyone know how things stand and possibly support it with references ?
Thank you and kind regards, T