Kuiper poses with one paw on an old HP graphing calculator.

Apollo Guidance Computer

Can you believe that we went to the moon w/ less computing power than this HP graphing calculator from 1995 that I still have for some reason? However, this calculator, along with the entire computer industry, might look a lot different today had it not been for the Apollo Guidance Computer.

Each Apollo Lunar mission had one AGC in the command module, and one in the lunar module (except for Apollo 8, which had no LM.) AGCs were the first major use of monolithic integrated circuits (or as we now call them, “integrated circuits.”) These are circuits with everything integrated into one piece of silicon without having to solder on more bits like resistors. They’re the foundation for all modern electronic devices.

A lot of the flight calculations for Apollo came from Mission Control’s big IBM mainframes, which were powered by “hybrid” integrated circuits. However, as the mission designs became more complex, NASA realized they were also going to need onboard guidance computers. In 1962, MIT made the case to NASA that they could make the AGCs more reliable, smaller, and 1/2 the weight if they switched to using a new kind of IC that had just been announced. The improved manufacturing process had been unveiled at a press conference in 1961 by Gordon Moore and Robert Noyce of Fairchild Semiconductors (those 2 left to found @Intel in 1968.)

By 1969, the Apollo program had purchased over one million chips of the Fairchild design, and the price per chip had dropped from $1,000 per chip to $20-30 per chip. Not only did NASA, MIT, and Fairchild work together on better manufacturing, but they also implemented vastly improved quality control processes. They even had separate manufacturing lines dedicated to Apollo, and invited astronauts to come speak with the plant workers to motivate them. Result was 0 AGC failures in flight, even when Apollo 12 was struck by lightning. Twice.

Original post: https://www.instagram.com/p/BdK61l4gnw1/

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