If you need a little extra firepower for your ship, look for a tank and pick it up. As long as you are holding the tank, it will act like a rotating turret for your ship and fire upon any enemy units that get within its range. The tank's cannons will rotate 360 degrees so it can attack enemies all around you. This is very useful if you do not want to deal with having to make constant maneuvers to avoid being hit by an enemy that is tailing you.