Apollo Guidance Computer Saved From The Scrap Yard

NASA needed a small and lightweight computer to send humans on their journey to the Moon and back, but computers of the day were made out of discrete components that were heavy, large, complicated, and unreliable. None of which are good qualities for spaceflight. The agency’s decision to ultimately trust the success of the Apollo program on the newly developed integrated circuit was an important milestone in computer history.

Given the enormity of the task at hand and the monumental effort it took, it’s surprising to learn that there aren’t very many left in existence. But perhaps not as surprising as the fact that somebody apparently threw one of them in the trash. A former NASA contractor happened to notice one of these historic Apollo Guidance Computers (AGC) at an electronics recycling facility, and thankfully was able to save it from getting scrapped.

The AGC was actually discovered in 1976, but it was decided to get the computer working again in time for the recent 50th anniversary of the Moon landing. A group of computer scientists in California were able to not only get the computer up and running, but integrate it into a realistic simulator that gives players an authentic look at what it took to land on the Moon in 1969.

Restoring a computer of this age and rarity is no easy feat. There aren’t exactly spare parts floating around for it, and the team had to go to great effort to repair some faults on the device. Since we covered the beginning stages of the restoration last year, the entire process has been extensively documented in a series of videos on YouTube. So while it’s unlikely you’ll find an AGC in your local recycling center, at least you’ll know what to do with it if you do.

Thanks to [Michael Wessel] for the tip!

23 thoughts on “Apollo Guidance Computer Saved From The Scrap Yard

    1. Eh…that’s kind of debatable at this point. By the book the word might have some negative connotations, but the term “enormity of the project” is pretty much accepted usage.

    2. Interesting. I was only familiar with definitions (3,4) through context. I would wager you were only with (1,2) until now.

      https://www.merriam-webster.com/dictionary/enormity

      enormity noun
      enor·​mi·​ty | \ i-ˈnȯr-mə-tē \
      plural enormities
      Definition of enormity
      1 : an outrageous, improper, vicious, or immoral act
      the enormities of state power
      — Susan Sontag
      other enormities too juvenile to mention
      — Richard Freedman
      2 : the quality or state of being immoderate, monstrous, or outrageous
      especially : great wickedness
      the enormity of the crimes committed during the Third Reich
      — G. A. Craig
      3 : the quality or state of being huge : IMMENSITY
      the inconceivable enormity of the universe
      4 : a quality of momentous importance or impact
      the enormity of the decision

  1. Guy: Yeah NASA? We have something to tell you!
    NASA: Ok?
    Guy: We found an original AGC!
    NASA: Sweet !
    Guy: But we tried to restore it
    NASA: Oh no, oh no ! Stop it!
    Guy: And we successed!
    NASA: Uh, ok? I guess

  2. Watched all of the installments over the past weeks. This is one of the coolest projects ever. And just in time for the 50th. Thanks Curious Marc and the gang for taking us along on your journey.

    1. So have I. I thought Marc couldn’t get any more awe-inspiring after restoring an original Alto, but the AGC is a true piece of world history. I can’t imagine what he’ll try next. Building an Analytical Engine? That requires a different set of skills!

  3. They landed, then crashed. They looked outside, the simulation showed the LEM still hovering at contact light altitude despite being touched down then went *fwip*.

  4. Don’t know if anyone here would be interested, but more likely than elsewhere… Back in the 80’s I worked support for the computer for the Galaeo probe. That is the company I worked for got the contract to build the on board computer. Was based roughly on the ATAC avionics computer normally used on the EW receivers of the day. (Yes, the same ATAC that was featured in the Bond movie, although in the movie they only showed a remote entry terminal.) Anyway, it was just a “screaming” little 8 bit built totally of descretes. From the moment we knew we had won the contract it took over a year to just gather the “AA” level parts from the IC manufactures. Quality control of the multilayer board and assembly process was seriously tight. (My own role was metrology measurement oversight, insuring that every measurement was tracable.)
    We finished the computer, ran it through shake n bake and delivered it ready to go to the probe assemblers….. Then the Shuttle disaster hit. Launching of the probe was understandably delayed.
    In fact, it was delayed so long that they totally redesigned the computer to take advantage of developements in microprocessor industry. I was told the new computer was based upon a Motorola 68020….
    So while “technically” I would be entitled to wear a Galeao patch I never bought one… because the one that flew wasn’t the same one I touched.
    Dems da breaks.

  5. Was very interesting in the whole process that you showed on your YouTube show on the rebuilding and fabricating repairs does anybody even remember a company called Heathkit yeah I remember going down to the corner store to check out my vacuum tubes the other thing most people are not really aware of diodes capacitors and all parts of integrated circuits it was called Fairchild although they never treated the child fairly if you were take a look at in the schematics and information pertaining to the Voyager system both one and two 1973 was the year Chrysler actually had electronic ignition didn’t come out till 1976 7 tell you what it was on the Voyager you have to understand that it’s still have parts of an 8-track tape and a whole bunch of other instruments invented for Noah most of which flu on weather balloons you also have to take into the consideration of buildings and corporations that are no longer there like the one next to Teterboro Airport used to do destructive analyzing as you noticed the computer was designed for specific reason so I guess that’s why it’s called a hack a hack is something that a machine really isn’t supposed to do but you you rearranged it to change its original purpose I can say that I was able to play tennis table pong on my television set

  6. As a former aerospace engineer with GE, from the 1980’s, I was enthralled by the series of videos documenting their achievements. Seeing how they continued to build one block on another, creating simulators and eventually replacing with real hardware, fixing bugs in the hardware, recovering the last state of the computer stored 50 years ago, and finally “landing” on the moon – stunning. A truly remarkable achievement.

    1. GE? Part that merged with RCA/Astro? I was also there in the late 80’s. Have a similar story about providing ground station support on an Interdata 70, all the way into the mid 1990’s. (That’s a core memory, paper tape boot loader, server in the same general category as a pdp-8/11)
      One thing I kept running into, most modern computer companies have No idea that there are projects that will need their hardware to work for decades. Getting spare parts for the Interdata meant getting them out of the museum.

      Another issue we ran into was some companies (particularly some of the more well known Japanese manufacturers) were on a ‘continuous improvement’ kick , which was great for consumer grade items. But since they kept the same part number, despite changing manufacturing procedures, we kept failing parts that were certified in a previous batches. They just saw it a improving the product, but we kept having to re-test them, frequently finding that improvements that made sense for earth bound consumers (such as reducing cost or increasing yield) did not work well in hard radiation or high heat/vibration situations.

  7. Being that it’s more than 50 years if you look at that iconic picture of Buzz Aldrin inside of the Apollo 11 module what does he have in his hand it’s called a micrometer Mike-crom-ator most likely it was a Starrett the Precision involved mating parts from different manufacturers Within a tolerance of 1 plus or minus 2 thousands and as far as the Saturn V rocket motor everyone will tell you that we can’t build one the same way one of the reasons is the blueprints were removed from existence due to the fear that our government would use the rocket just like our friends in North Korea wants to with all due respect my question it’s not a question it’s a fact when welding 2 Wells when done properly is stronger than the two parts of metal it is joining

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