Ok so I have been wanting to build a pretty big space station around Kerbal. I would love to store some huge fuel tanks in space to have other craft later refuel for long interplanetary voyages. Since the Kerbals don't care about how much money I spend, I figure that's grand. Now the problem is I would like to be able to use a sort of "Tug Boat" ship to move my modules around and link them up. I keep trying to build ships that will let me move laterally in space but so far all I do is rotate or roll. RCS's are giving me a fit. I suspect this is about a center of gravity issue and I don't see this problem going away. If I were to get my "Tug Boat" balanced nicely, whenever I would connect to something in space I am quite sure that will screw up the COG up again and start this mess over. Any suggestions? Are you aware of anyone or anything used to solve this issue? Thanks and Launch Safe, FlyMario