re: Energy
I was thinking they would meet in LEO. The incoming craft would come up from behind the outgoing craft, attach somehow, exchange velocities, and then separate. I was also thinking along the lines of this being used with round trip supply crafts to Mars, or the Moon. I knew the forces would be great on the initial attachment.
I thought of this when I realized how much energy would be lost for a return ship to go into orbit around Earth. Mean while, we have other ships leaving LEO to Mars or elsewhere that need energy.
I guess I'll leave this idea for the Science Fiction realm. Actually, I know a good story I could use it in.