Actually I use steering for my AI. Since it is a full 3D environment (outer space) A* isn't a viable solution. In my implementation a straight line is calculated to the target and the AI use 'feelers' to keep from crashing into objects. Eventually the AI will work their way around objects and get close enough to attack if thats their goal. The movement is nowhere near as precise as A* but is is a workable solution in the case of 3D star systems and 3D surface maps.