Judgment Overrode Algorithm to Save First Moon Landing

(p. 29) On July 20, 1969, moments after mission control in Houston had given the Apollo 11 lunar module, Eagle, the O.K. to begin its descent to the moon, a yellow warning light flashed on the cockpit instrument panel.
“Program alarm,” the commander, Neil Armstrong, radioed. “It’s a 1202.”
The alarm appeared to indicate a computer systems overload, raising the specter of a breakdown. With only a few minutes left before touchdown on the moon, Steve Bales, the guidance officer in mission control, had to make a decision: Let the module continue to descend, or abort the mission and send the module rocketing back to the command ship, Columbia.
By intercom, Mr. Bales quickly consulted Jack Garman, a 24-year-old engineer who was overseeing the software support group from a back-room console.
Mr. Garman had painstakingly prepared himself for just this contingency — the possibility of a false alarm.
“So I said,” he remembered, “on this backup room voice loop that no one can hear, ‘As long as it doesn’t reoccur, it’s fine.'”
At 4:18 p.m., with only 30 seconds of fuel remaining for the descent, Mr. Armstrong radioed: “Houston, Tranquillity Base here. The Eagle has landed.”
Mr. Garman, whose self-assurance and honed judgment effectively saved mankind’s first lunar landing, died on Tuesday outside Houston.

For the full obituary, see:
SAM ROBERTS. “Jack Garman, Who Saved Moon Landing, Dies at 72.” The New York Times, First Section (Sun., SEPT. 25, 2016): 29.
(Note: the online version of the obituary has the date SEPT. 24, 2016, and has the title “Jack Garman, Whose Judgment Call Saved Moon Landing, Dies at 72.”)

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