The Gemini spacecraft carried the first fully functional computer in space, it ran with a clock speed of about 7kHz, uses 26 bit data and 39bit memory words, with 4096 words of memory. It was one of the oddest computer architectures ever developed, for a tiny niche, only ever used on the Gemini. Some of the design may have made it into the Saturn Launch Vehicle Digital computer, but

The best source of information on the Gemini On Board Computer is here:
https://www.ibiblio.org/apollo/Gemini...
Amazing work has been done reconstructing the limited documentation into a version of the architecture and approximations of the software.

The simulator I used to show the computer operating is Reentry:
https://reentrygame.com/


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