Apollo Guidance Computer Part 1: Restoring the computer that put man on the Moon

This youtube series of video, follow a group that restored an Apollo Guidance Computer that a collector basically pulled from the trash. [this video] My favorite part is when they needed the version of the software that was used for the moon landing but they only had the source code for a previous version (scanned from giant binder) and the hash value of the version of the landing. By a series of educated guesses, by reading memos and by analysis of the source code they modified the old code the exact way so it gave them the correct hash, confirming that they correctly and exactly recreated the original code. It's being a while and I go from memory, I might have some details wrong. See this video for this story. [link]

CuriousMarc on Youtube has a very large playlist of him and a few others restoring the apollo systems they have been able to get their hands on, and youre absolutely correct on the hacky possibilities. There was no authentication, just lock on and issue commands. They were not only able to restore pretty much everything to a working apollo comms and control system, they were even able to use lab equipment to communicate with apollo outright. I linked the first part of the series. Its a long one but very worth the watch even if you arent into everything they cover. Many sats were and are similar, theres not much security. Newer ones with specific uses are most definitely encrypted. The only real saving grace is that the size of dish/antenna and power you need to do anything with stuff actually in space at long distances is beyond what most people could do (not saying a very dedicated nerd couldnt, look at SaveItForParts for example). [this video]

Don is still around, and is still awesome! His memory for events around that time is surprisingly sharp, for it being 50 years ago. He's been an invaluable resource for us at the VirtualAGC project [1]. He provided over half (!) of the AGC programs we've made available, including LM software for Apollo 5, 9, 10, 11, 12, 13, and 15-17, plus several other ground development programs. He also was the source of a majority of the schematics that we used in the AGC restoration [2] -- I can say with 100% confidence that it wouldn't have been possible to get that computer working again without his help. He's got a book out now, Sunburst and Luminary [3], that is very good and goes into a lot of technical detail on the LM software, without getting too much into the weeds. I highly recommend it if you're interested in that sort of thing! [1] [link] [2] [this video] [3] [link]