High Quality Content by WIKIPEDIA articles! The Martin AN/FSG-1 Antiaircraft Defense System was an electronic fire distribution center to computerize Cold War air defense (AD) command posts from manual plotting board operations to automated command and control of remote surface-to-air missile (SAM) launch batteries. The 10 United States Army C3 systems used radar netting ("electronic umbrella") at Missile Master military installations for coordinating ground-controlled interception by Nike and MIM-23 Hawk missiles. The vacuum tube fire control logic reduced the time to designate the appropriate missile battery to launch if an enemy target had intruded into a defense area where an AN/FSG-1 system was deployed.