Manufacturing New Connectors For The Apollo Guidance Computer

The fiftieth anniversary of the Apollo 11 mission – the flight that first took man to the surface of the moon — is coming up. By the time this post is published, some YouTube channel will invariably be running a real-time-but-delayed-fifty-years live stream of all the mission events, culminating on the wee hours of July 20th where we wait hours for someone to figure out how to open the door.

[CuriousMarc] and space hardware collector [Jimmie Loocke] have a different type of anniversary in mind. They have an Apollo Guidance Computer sitting on a bed in a motel room, and they’re going to get it up and running by July 20th. That’s the plan, at least. This is no easy feat: the Apollo Guidance Computer looks like two 19-inch, 1U rack units, with no standardized connectors to talk to any other hardware. They’ve just figured out the hardest part of this build by making their own NASA-spec contacts. They can now connect external hardware to the AGC, probably for the first time in decades.

As it stands now, there are external ports on the gigantic bricks of aluminum enclosure that comprise the two AGC modules. These ports are just female pin headers, completely unlike any standard that can be found today. However, the folks at Samtec managed to build the male versions of these pin headers for this project. These pins fit the female sockets on one end, and are standard, square-shaped wire wrapped headers on the other. They are mounted in a milled plastic block, and after everything is wired up, [Marc] and [Jimmie] had a direct electrical connection to the Apollo Guidance Computer. The machine lives again.

There’s still a lot of work to do to get these bricks of computer up and running for the 20th, but this is fantastic progress. Already they’re single-stepping the AGC and running the P63 program that landed on the moon. Check out the video below.


20 thoughts on “Manufacturing New Connectors For The Apollo Guidance Computer

  1. Unless they have released a video after the one linked in the article (they haven’t on youtube), they have not actually connected their debugger to the real AGC yet. What they have done is connected the debugger to a FPGA pretending to be the AGC, and that is what is shown in the video.

    They have started construction of the actual hardware to interface to the AGC (the title image of the video shows the newly fabricated pins being pressed into the connector housing) but not actually gone through debugging their real AGC with the debugger. It sounds like they are very close to this milestone (and presumably by then they will have the Applied Science DSKY to go with it) but there are some serious hurdles they need to overcome at some point before the system is fully up and running.

    The most significant of which is that the AGC they have is damaged, there is a fault in one of their core memory modules which will prevent it from being able to operate normally. It is unclear if they can work around this with their debugger, but based on my understanding of the situation this is unlikely. They have located suitable replacement core memories (for example, there is one at the MIT museum) but as far as I know none of them have been donated to this project, and the current plan is to instead make a replica module using the newly fabricated pins.

    The other, hopefully less significant, hurdle is that they do not have any ‘rope memory’ ROMs. The good news is that they do have the firmware that was stored on the ROMs (as shown in the video), and they also have part of a rope memory simulator, which they are actively working on repairing/reverse engineering so that they can load the ROMs onto their actual hardware. It may also be possible to fake a ROM with their debugger, but as far as I know they are not pursuing this route at the moment. Like with the core memories, they have also located suitable rope memories (for example, Francois Rauten has a set for AS-202, the first flight to include the AGC)

      1. I’d say the opposite. These guys are obviously doing something very unusual and interesting.

        Quite often, the protagonists in a Netflix film end up in a motel, hiding from the cops / performing DIY surgery on bullet wounds / cleaning their weapons in preparation for a heist ……. I’m thinking maybe these guys were doing some kind of documentary?

        1. “Quite often, the protagonists in a Netflix film end up in a motel, hiding from the cops / performing DIY surgery on bullet wounds”

          Ah, yes, the obligatory bullet extraction. Never forget the included bullet dropping into a metal pan, with the required “Clank” as it hits bottom. (Pun intended)

      2. Have you never been totally consumed by a project? Have you never hopped on a plane because the one example of something you have always wanted to see (or ride, or use) is somewhere other than where you live?

        One man’s “waste of time” is another man’s (or woman’s) life’s work.

        What would *you* do if the owner of the only example of the Apollo Guidance Computer which stood a chance of becoming operational called you up and asked you to help him get it running again?

        If you consider that a waste of time, perhaps the remainder of this site is a mystery to you as well.

      3. The definition of “having a life” seems to vary quite a lot.

        “having a life” mostly means: waste your time with: drinking, socializing (which in many cases is nothing more then “wasting other peoples time by hanging out with other people”).
        I think that many people who claim to “have a life” have a lack of hobbies or purpose in life. Seeing that other people amuse themselves with great passion about something they just don’t understand scare them. Saying that the other one has “no life” is of the same level as a disappointed 6 year old saying “stupid” to the (so much better) toy of another 6 year old on bring-your-toy-to-school-day.

        So every time somebody tells me that I “have no life” just after that I have shown them my latest completed project, I feel sorry for them and can’t help smiling proudly.

    1. It’s not exactly standard practice(not that doing anything with antique electronics is, at a population level); but, at least in the US, a motel is an easy, fairly cheap, way to get some temporary space in a reasonably convenient location, with amenities like a bathroom, an internet connection, at least somewhere to get meal nearby, etc.

      Storage units are cheaper in the longer term; but more Spartan and usually out in the sticks; and somebody’s basement/workshop/hackerspace only works if all parties are in convenient proximity.

      It’s certainly less usual than many of the guests the motel will have; but unless they leave soldering iron burns all over the place it sure won’t be the worst thing room service has ever had to deal with.

    2. What does our culture have to do with this? I don’t understand people who need to knock America to feel better about themselves. Yes, it is a minor one, but needless.

      1. I’m not knocking it, i just thought it was a only hollywood thing. Seems like actually it’s quite widespread and seems to me like a great idea. If i ever have the opportunity I’l be utilising it where I live. (Obviously not the DIY surgery or such like).

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