Ion Engines

Allows Ion Engines to be added to new warship designs, for newly built ships or Refit of existing ships.

Compared to the starting tech, Chemical Engines, increases movement in tactical combat by 50% from 2 hexes per combat turn to 3.

Has no effect on interstellar movement.

Increased tactical movement speed is helpful in exploiting terrain, countering enemy's use of terrain, and to some extent aiding in avoiding enemy launched weapons (torpedoes etc).