Nike: Firing a Missile
Once the Army Air Defense Command Post received word of an impending attack, it notified its battalions. As the target entered the range of the acquisition radar and the missiles at each battery readied for launch, a "blue alert" status sounded, signalling that all personnel should go to battle stations. Three missiles were brought above ground, one at a time, on the elevator, and pushed to the satellite launchers and locked in place with pins. The fourth missile was brought to the surface on the elevator, where it could also be launched.
The chief of the launching section removed the air regulator safety pin and the missile support yoke safety pin. The launching crew checked for stray voltage and continuity at the detonator receptacle on the launchers with the squib (or detonator) tester. If test readings were within acceptable tolerances, the launching crew made the connections and removed the booster squib shorting plug. The chief of the section then announced over the intercom: "Launcher 1, 2, 3, and 4 ready."
An Army film on Nike Hercules provides a visual re-creation of the firing of a missile. Safety was the central theme stressed in the film. Among the precautions that were employed were a series of color-coded streamers attached to critical plugs and keys. For example, red streamers were attached to those mechanical parts that had to be removed before the missile could be launched. Even when the streamers were removed, personnel had to use special keys to unlock the "awesome power" of the missile system.
After preparing the missiles for launch and checking the area to ensure all personnel were below, the section chief descended into the underground personnel room, closing the escape hatch cover behind him. The section chief then entered the magazine room, closed the vents, and returned to the personnel room, securing blast-proof doors. He checked the pin board to ensure that all the safety pins and the booster squib shorting plug were present. At that time, he also inserted the crew safety keys and placed them in the "fire" position. At the launching control console, there was a green "ready" light for each section, and a green numbered launcher identification light for each section in action. The "missile prepared" meters for each section indicated the number of missiles ready for launch in each section.
As the target came within range of the acquisition radar, the battery control officer corroborated the target appearing on the plan position indicator with the early warning plot data received from the Air Defense Command Post. At this time, the alert status switched from blue to red. The battery control officer and the acquisition radar operator designated the target to the target-tracking radar, and interrogated it by using the identification friend-or-foe facilities on the console.
The missiles were then raised to a vertical position. The missile-tracking radar shifted to the designated missile and cast its electronic beam onto it. The battery control officer determined the proper time to fire the missile using the plotting board information, his knowledge of the defense area, the geographic limitation of his field of fire, and the method of engagement directed by the Army Air Defense Command Post. The "ready to fire" lamp in the battery control console presented a visual summary of the state of readiness of the guidance and launching area. When the missile-tracking radar and target-tracking radar engaged, the computer was on line, and the target identified as the enemy, the "ready to fire" lamp changed from amber to green. After these events, the battery control officer could fire the missile. If necessary, he could also designate the target as friendly aircraft, by pressing the "friend" button at the acquisition radar control panel. The battery control officer could also designate a new target that had priority by placing the "designate-abandon" switch in the "abandon" position. If the target was abandoned, the battery control officer had to designate a new target.
Historian Merle T. Cole, in his description of a Nike installation in the Maryland air defense area [W-25: The Davidsonville Site and Maryland Air Defense, 1950-1974], described the order in which the missiles were fired:
During a fire mission the missile on the elevator-launcher of one launching section is fired, followed by the missile on the elevator-launcher on the [second and third sections]. Using this sequence each section can reload the elevator-launcher while the other two sections are firing, and consequently maintain the maximum rate of fire. This procedure is followed as long as missiles are available in the undergroond Imagazinesj. When these have been exhausted, the three missiles located on satellite launchers at each section are fired as desired by the commander.
When the battery control officer operated the "fire" button, the missile launched. Four seconds after "missile away," the computer ordered the missile to execute a 7g dive (1g is equal to 32.2 feet/second/second). At the same time, the computer modified this order, if necessary, to insure that the missile ground path was parallel to the line between the launcher and the intercept point. Steering orders were transmitted to the missile via the missile-tracking radar. At a predetermined interval before the time of intercept, the "burst" signal was transmitted to the missile, and an arming device detonated the warheads.
The Nike system could fire one missile per minute for one hour against targets at moderate ranges (approximately 25,000 yards) and, if required, two missiles per minute for short periods against short-range targets (approximately 15,000 yards). Actual rates, however, varied according to prevailing circumstances.
Nike crewmen needed a minimum of 36 seconds to launch the first missile. This included approximately 30 seconds to acquire, identify, designate, and track a target; four seconds for computer settle; and two seconds for the fixed time interval between the initial fire order command and missile launch. A new missile could be launched approximately 11 seconds after the bursting or abandonment of the previous missile. After the previous target has been tracked, the acquisition radar operator was free to examine and interrogate any new targets.
There were two situations in which a missile could be rejected. Either the missile-tracking radar failed to get an adequate signal response from the missile, or the missile did not fire within five seconds aRer the "fire" command signal. As soon as the red "reject" lamp lit, the elevator was lowered, and the rejected missile was removed; another missile was then loaded onto the elevator launcher.