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.

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Hackaday Links: July 28, 2019

It looks like Apple is interested in buying Intel’s modem chip business. Seriously interested; a deal worth $1 billion could be announced as early as this week. That might look like a small potato purchase to the world’s biggest company – at least by market capitalization – but since the technology it will be buying includes smartphone modems, it provides a look into Apple’s thinking about the near future with regard to 5G.

It turns out that Make Magazine isn’t quite dead yet. [Dale Dougherty], former CEO of Maker Media, which went under in June, has just announced that he and others have acquired the company’s assets and reformed under the name “Maker Community LLC.” Make: Magazine is set to resume publication, going back to its roots as a quarterly publication in the smaller journal format; sadly there’s no specific word about the fate of Maker Faire yet.

The hoopla over the 50th anniversary of Apollo 11 may be over, but we’d be remiss not to call out one truly epic hack related to the celebration: the full restoration of an actual Apollo Guidance Computer. The AGC was from a test model of the Lunar Module, and it ended up in the hands of a private collector. Since November of 2018 the AGC has been undergoing restoration and tests by [Ken Shirriff], [Mike Stewart], and [Carl Claunch]. The whole effort is documented in a playlist by [Marc “CuriousMarc” Verdiell] that’s worth watching to see what was needed to restore the AGC to working condition.

With the summer sun beating down on the northern hemisphere, and air conditioners at working extra hard to keep things comfortable. [How To Lou] has a quick tip to improve AC efficiency. Turns out that just spraying a fine mist of water on the condenser coils works wonders; [Lou] measured a 12% improvement in cooling. It may not be the best use of water, and it may not work as well in very humid climates, but it’s a good tip to keep in mind.

Be careful with this one; between the bent spoon, the syringe full of amber liquid, and the little candle to heat things up, this field-expedient reflow soldering setup might just get you in trouble with the local narcotics enforcement authorities. Even so, knowing that you can assemble a small SMD board without a reflow oven might prove useful someday, under admittedly bizarre circumstances.

From the “Considerably more than 8-bits music” file, check out the Hull Philharmonic Orchestra’s “8-Bit Symphony.” If your personal PC gaming history included a Commodore 64, chances are you’ll recognize songs from titles like “Monty on the Run”, “Firelord”, “Green Beret”, and “Forbidden Forest.” Sure, composers like [Ben Daglish] and [Paul Norman] worked wonders with the three-channel SID chip, but hearing those tunes rendered by a full orchestra is something else entirely. We found it to be particularly good background music to write by.

Space Age Bitcoin Mining On An Apollo AGC

Imagine you’ve got an Apollo Guidance Computer, the machine that took men to the Moon 50 years ago. You’ve spent ages restoring it, and now it’s the only working AGC on the planet. It’s not as though you’re going to fly to the Moon with it, so what do you do with it? Easy – turn it into a perfectly awful Bitcoin mining rig.

The AGC that [Ken Shirriff] and others have been restoring barely resembles a modern computer. The AGC could only do about 40,000 operations per second, but raw speed was far less important than overall reliability and the abundant IO needed to run a crewed spacecraft. It was a spectacular success on the Apollo missions, but [Ken] wanted to know if turning it into a Bitcoin mining rig was possible.

[Ken] gives a great overview of how Bitcoin mining works, with one of the best explanations of the hashing algorithm we’ve seen. Getting that to run on the AGC was no mean feat, especially with limits imposed by the memory addressing scheme and the lack of machine instructions for manipulating words. He eventually got it working, though, clocking in at a screaming 10.3 seconds per Bitcoin hash. [Ken] estimates that the first coin will be successfully mined in a mere 400 zettaseconds, which is about a billion times older than the universe. With about 13 quadrillion years to the first ka-ching, you have plenty of time to watch a block mined in the video below; alas, it was an old block, so no coins were awarded to compensate the team for their efforts.

This isn’t the first time [Ken] has implemented a useless Bitcoin mine. The Xerox Alto mine was actually fast compared to the AGC, but it sure beats the IBM mainframe and punchcards.

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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.

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I Went To The Moon And All I Got Was This Lousy T-Shirt

It’s been a long time coming but [Fran] finally has a DSKY display, a replica of the user interface display found in the Apollo Guidance Computer. The best part? It’s a t-shirt.

This build is a long, long, time in the making first beginning in 2015 when Fran started investigating the DSKY of the Apollo Guidance Computer. At the time, there were reproductions, but honesty they were all terrible. The reproductions used off-the-shelf seven-segment LEDs or light pipes. The real DSKY was a work of art and at the time probably the most complex electroluminescent display ever created. This led [Fran] to a very special trip to the annex of the Air and Space Museum where she was allowed to inspect a real DSKY display. She got all the measurements, and with some non-destructive investigation, she was able to piece together how this very special display was put together.

With that information, [Fran] was able to figure out that this display was a fairly complex series of silk screens. If it’s silk screen, you can put it on a t-shirt, so that’s exactly what [Fran] did. This used a DIY silk screen jig with phosphorescent inks. It’s not an electroluminescent display, but it does glow in the dark.

While this DSKY t-shirt does glow in the dark, that means it’s not an electroluminescent display like the original DSKY. That said, screen printed electroluminescent displays on a t-shirt aren’t unheard of. Several years ago, a screen printing company did a few experiments with EL displays on wearables. Of course, if you want a real electroluminescent DSKY display, [Ben Krasnow] has a very modern reproduction of the screen printed display. The electronics of [Ben]’s project do not resemble what flew to the moon in any way whatsoever; the original DSKY had relays. That said, we’ve never been closer to a modern recreation of the display from an Apollo Guidance Computer, and we have [Fran] and [Ben]’s work to point us forward.

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[Ben Krasnow] Makes A DSKY

There are hundreds if not thousands of artifacts from the Apollo program scattered around the globe, some twisted wrecks at the bottom of the ocean, others lovingly preserved and sitting in museums or in the hands of private collectors. All of what’s left is pretty much pure unobtainium, so if you want something Apollo-like, you’re probably going to have to make it yourself.

[Ben Krasnow] took up the challenge to make an electroluminescent Apollo-era DSKY display from scratch, with outstanding results. The DSKY, or “display and keyboard”, was the user interface for the Apollo Guidance Computer, the purpose-built digital navigation system that got a total of 24 men there and back again. [Ben] says it took a long time to recreate the display, and we can see why. He needed to master quite a few skills, including screen printing to get the glass-panel display working. The panel is a sandwich of phosphorescent paint, a dielectric, and conductive ink. The ink is silkscreened on the back to form the characters, all applied to indium tin oxide (ITO) conductive glass. A PCB with the same pattern of character segments lays behind that, driving each segment with 300 volts or so through a trio of HV507 high-voltage shift registers. It’s an impressive bit of engineering and gives off a decidedly not-homebrew vibe.

In the video below, [Ben] goes into detail about the trials he experienced on the way to this amazing endpoint, not least of which was frying chip after chip due to ineffective protection diodes in the shift registers. That’s an epic debugging story that’s worth the price of admission all by itself. It’s not the only DSKY in town, of course – [Fran Blanche] has been working on one for a while too – but there’s just something about that blue glow that we really like.

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An Apollo Guidance Computer Laid Bare

An Apollo Guidance Computer probably isn’t a machine that’s likely to come the way of most Hackaday readers. The device that played such a vital role in taking astronauts to the Moon and bringing them home again is hardly a common find, even if it is one of the most iconic machines of its type and era.

[Carl Claunch] was approached to assist in the restoration of an AGC, and while he can’t reveal any information about its owner he is at liberty to document his progress. The result is a fascinating in-depth technical examination of the device over multiple blog posts, and is well worth a read for anyone with an interest in the Apollo program. It’s an ongoing progression of blog posts that are probably too numerous to list individually, but include the construction of a substitute for the DSKY control panel as well as looking at the device’s memory and construction. [Carl] then embarks on a series of posts looking at the restoration itself. This is where we see the computer in greatest detail, and learn the most about it.

If you think you might have seen [Carl]’s name here before, you’d be right. One of his past exploits was getting the first version of FORTH running on an IBM mainframe.