Source Code for the Apollo Eleven Mission

[Hornbein]

The source code was preserved as printouts and is available. The machine code was hard wired into core memory : a one had two wires through a core while a zero had one. It took months to do this by hand so everything had to be perfect in advance. (It would though be impervious to cosmic rays.) There were chips in the system that boasted two gates apiece. The mission consumed 60% of the chip output of the United States.

The astronauts had to enter commands as decimal numbers which they memorized. There are whimsical comments in the source code, including a quotation from Shakespeare. The system failed and rebooted five times during the descent.

 

[FactChecker]

RIP, Margaret Hamilton. She died on Sept. 30, 2026, at the age of 90.