The evolution of attitude control systems related to NASA space vehicles is'covered. Successful employment of electric thrust vector control on the Mercury-Redstone was followed by the employment of fluid power for Juno II, Saturn, and advanced Saturn. A comparison is made of electric and hydraulic systems as exemplified by the Pershing and Mercury-Redstone. Other illustrated applications of fluid power related to space vehicles are presented. Advantages of fluid power are presented in keeping with the requirements and perspectives of the Marshall Space Flight Center.