The ESSM takes the existing guidance section from the RIM-7P and fits it to an entirely new rear-section. The new missile is in diameter instead of the previous 8 inches, which allows for a much more powerful motor. It also eliminates the mid-mounted wings entirely, replacing them with long fins similar to those on the Standard missile (and practically every other Navy missile since the 1950s) and moves guidance control to the rear fins. The tail-fin based steering of the ESSM uses up more energy but offers considerably higher maneuverability while the engine is still firing.