There is no gravity in space, so the term "weight" usually only refers to when a ship is in an environment that does have gravity, or when it is accelerating, decelerating, or changing directions due to the artificial gravitational forces imposed upon the ship through [centrifugal] force. The Mass of the ship in turn will determine how much the ship "weighs" during a turn or any maneuver. The less Mass, the less weight the engine will have to deal with when accelerating or decelerating. This is…