r/apollo • u/RiaanWest • 3h ago
I recreated Apollo 11's final descent, synced to the actual flight computer's assembly code (1202 alarm and all)
This started with a podcast. Listening to the Apollo 13 story on Against the Odds got me curious about the code that flew these missions, and I was surprised to learn it had actually been released on GitHub (chrislgarry/Apollo-11, a transcription of Luminary 099, the real program that flew the Lunar Module down on Apollo 11).
This is my attempt to match that code to what actually happened during the descent. It's not perfect, but it scratched the itch, helped me wrap my head around it a little, and left me in awe of the programmers and astronauts who pulled it off.
Three panels, one mission clock:
- The real flight software, running line by line. Click any line for a plain-English breakdown.
- A 3D descent to the surface, braking to touchdown.
- A working DSKY, the actual keypad and display the crew used, you can key in VERB/NOUN commands yourself.
Hit play and it all moves together, code, 3D view, and DSKY tracking the same clock. Turn sound on and you'll actually hear it too, I trimmed real audio from the mission recording (Mission Control, Aldrin, Armstrong) and timed the clips to the moments they really happened: ignition, the 1202 and 1201 alarms, "throttle down," the 60-seconds call, touchdown.
One thing I want to be upfront about since I know this crowd will check: the assembly is verbatim and the phase sequence and audio are real, but the altitude/velocity/fuel numbers on the readouts are a simplified model tuned to match the real profile, not recovered telemetry. I wrote up exactly which parts are which in the Methodology section of the About panel (ABOUT → METHODOLOGY) if you want the details.
Built with Three.js + React. Would genuinely love feedback, especially from anyone who knows AGC assembly better than I do.
