When the Apollo 11 guidance software developed under Margaret Hamilton's leadership began flashing a sequence of 1201 and 1202 alarms more than seven minutes before Eagle touched down in the Sea of Tranquility, it was doing what MIT engineers had designed it to do years earlier: restarting and protecting higher-priority tasks so critical landing computations could continue, a design choice that helped save the landing with about 45 seconds of fuel remaining

When the Apollo 11 guidance software developed under Margaret Hamilton's leadership began flashing a sequence of 1201 and 1202 alarms more than seven minutes before Eagle touched down in the Sea of Tranquility, it was doing what MIT engineers had designed it to do years earlier: restarting and protecting higher-priority tasks so critical landing computations could continue, a design choice that helped save the landing with about 45 seconds of fuel remaining

At 102:38:26 mission elapsed time, the Apollo 11 lunar module was still more than seven minutes from touchdown when Neil Armstrong announced a program alarm. The code was 1202. Eagle was roughly 33,500 feet, or 10 kilometers, above the Moon, and neither Armstrong nor Buzz Aldrin knew whether the alarm required an abort. The Apollo 11 Lunar Surface Journal records Houston clearing the crew to continue 27 seconds after Armstrong’s first alarm call…