I can't make a fleet with the terror star in it. When I made the fleet, the game crashed.

I am haveing touble with the ship editor too. I was making a recreation of the Battlestar Pegasus when all of a sudden the ship starts reacting badly to extra pieces and systems. If I add anything, the ship's appearance gets screwed up. When I say "screwed up" I mean parts of the ship getting distorted, or becoming invisible. Can anything be done about this?