Apollo 11 Program Alarms (1998)

Gene Kranz, in his book Failure Is Not An Option, describes one of the simulator runs for Apollo 11 in which the Simsup (simulation supervisor) threw a 1201 alarm at the Mission Control team. The controller receiving the alarm panicked and called for an abort, and Kranz passed the abort order on to CAPCOM. Afterwards, the Simsup told Kranz, "This was not an abort. You should have continued the landing...You violated the fundamental rule of Mission Control: You must have two cues before aborting. You called for an abort with only one!"

The controller dug more thoroughly into program alarm codes after that simulation, and wrote a new mission rule specifying a series of program alarm codes for which an abort would be called. 1201 and 1202 were not among those alarm codes. Thus, when the 1202 showed up during the actual descent, the controller was able to say, "We're Go on that alarm," and when the 1201 happened shortly thereafter, he could say, "It's a Go--same type--we're still Go." Shortly thereafter, history was made...not just because the MIT programmers had done their job well, but because the flight control team in Houston had also done their job well.