What are some interesting facts about the Apollo 11 mission that most laypeople don’t know? originally appeared on Quora: the place to gain and share knowledge, empowering people to learn from others and better understand the world.
There are many facts about the Apollo 11 mission that most laypeople aren’t aware of, and that’s one of the reasons I wrote my book Shoot for the Moon. Here’s just one: the actual landing was more dangerous than most people knew then or know now.
During the descent to the surface, a rendezvous radar that wasn’t needed had been turned on, and required just enough of the primitive (approximately 72 kB of memory and 1 MHz of processing speed!) Apollo Guidance Computer’s processing power that it overloaded the AGC and prevented other, more vital jobs—like landing the lunar module (LM)—from completing. This triggered 1201 and 1202 alarms (“Executive Overflow”), which caused the computer to reboot.
But it did it quickly, and no guidance or navigation data was lost. The primitive but reliable computer continued to do its job—it just relegated low-priority jobs like the unnecessary rendezvous radar to the back of the queue.
But the alarms took up so much of the attention of Neil Armstrong and Buzz Aldrin in the LM that by the time those were sorted out, and they were able to concentrate on the view outside their small triangular windows as they neared the lunar surface, they were down-range from where they expected to be, and all their time studying detailed maps of their landing site was for nought. That’s because when the LM separated from the command service module, the small tunnel between the two hadn’t been completely depressurized, and at separation, it was like a cork popping from a champagne bottle—it added enough impetus to the undocking that the LM’s velocity was slightly increased and made a slight difference to the approach path.
So about ten minutes later, Armstrong had lost track of the landmarks he had memorized, and when he realized that the AGC was about to land them on the side of a large crater, with many car-sized boulders strewn about. As time and fuel began to run out, he took over manual control of the LM and began looking for a suitable place to land—on an alien world no human had ever touched, in a strange-looking spaceship no one had ever landed before.
Another little-known fact: although Buzz Aldrin’s title description was “lunar module pilot,” he never piloted the LM, and never trained to do it. And in every other Apollo mission involving the LM, the lunar module pilot never did any piloting. That’s because the commander of each Apollo mission was the only one who trained to ‘fly” the LM—and the only astronaut who ever piloted it. But early on in the manned space program, it was decided that no astronaut would be labeled “co-pilot.” (In the Gemini program, which involved a two-man crew, the positions were “command pilot” and “pilot,” even though the pilot did almost no actual piloting.) The truth was, in the crewed LM, the lunar module pilot actually did act as a co-pilot—with some of the duties of a navigator and systems engineer thrown in.
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