The Computer Hack That Saved Apollo 14 (2017) [video]

If you're interested in this, I can recommend Sunburst and Luminary: An Apollo Memoir, by Don Eyles. http://www.sunburstandluminary.com/SLhome.html

It was Don who wrote the Apollo lunar module software that handled the whole landing phase, and was responsible for the hack that saved the Apollo 14 mission. The book details the whole history of the LEM software development. I particularly like the part relating to the details behind the 1201 and 1202 program alarms on Apollo 11. I hadn't realized that they actually signified the LEM computer doing a full software reboot. Not what you really want to see on a fly-by-wire spacecraft during the landing phase. This turned out to be OK because the critical tasks were restartable, as they anticipated a power glitch and really didn't want to crater if one happened at a critical momemnt.

Don Eyles, the programmer who devised the guidance computer patch, published a book, Sunburst and Luminary, earlier this year that provides more details on his work as a programmer for the Apollo computer while at MIT. It focuses primarily on Apollo 11 and the 1201/1202 errors it encountered during descent. He discussed the Apollo 14 fix in a 1971 article in Rolling Stone magazine.

This is basically an article that says go watch a video by Scott Manly who is a very good communicator about space topics. He has lots of videos about various Apollo era topics and recent events that are particularly convoluted when they came out. Great resource highly recommended.

https://www.youtube.com/user/szyzyg