News The code that took America to the moon was just published to GitHub

[GodAtum]

The AGC code has been available to the public for quite a while–it was first uploaded by tech researcher Ron Burkey in 2003, after he’d transcribed it from scanned images of the original hardcopies MIT had put online. That is, he manually typed out each line, one by one.
“It was scanned by a airplane pilot named Gary Neff in Colorado,” Burkey said in an email. “MIT got hold of the scans and put them online in the form of page images, which unfortunately had been mutilated in the process to the point of being unreadable in places.” Burkey reconstructed the unreadable parts, he said, using his engineering skills to fill in the blanks.
“Quite a bit later, I managed to get some replacement scans from Gary Neff for the unreadable parts and fortunately found out that the parts I filled in were 100% correct!” he said.

The effort made the code available to any researcher or hobbyist who wanted to explore it. Burkey himself even used the software to create a simulation of the AGC.

As enormous and successful as Burkey’s project has been, however, the code itself remained somewhat obscure to many of today’s software developers. That was until last Thursday (July 7), when former NASA intern Chris Garry uploaded the software in its entirety to GitHub, the code-sharing site where millions of programmers hang out these days.

https://github.com/chrislgarry/Apollo-11/

Do you think Orbiter devs could use this for addons?

 

[ADSWNJ]

https://www.reddit.com/r/Programmer...idance_computer_source_code_now_on/?limit=500

Worth a good read, if you like this original source code.

 

[SolarLiner]

Check out the issues tab too, it's all just perfect.

 

[indy91]

Someone should make an addon with this code. I call this project: Project Apollo - NASSP :rofl:

 

[jedidia]

Basically you'd have to write an emulator of the hardware used to run the code on... That would be quite a project, but there are people here that might be crazy enough to attempt it.

 

[indy91]

Basically you'd have to write an emulator of the hardware used to run the code on... That would be quite a project, but there are people here that might be crazy enough to attempt it.

Yeah, that would be quite the feat. I imagine a very realistic simulation of the Apollo program implementing such an emulator. So realistic that it takes many, many years to complete and will look abandoned to most people. But eventually it will have a proper release. Maybe even within the next few months. At least if the probe is gracious as well as the time schedules of the few contributors working on such a project.

 

[Hlynkacg]

I have the Neff copy on a USB drive along with several of the original manuals that I've been using as references for my own code but I'll be downloading this for sure.

I'm pretty sure one of the NASSP guys was working on a software emulator of the agc's operating system that (in theory) should be able to run the upper level programs in this code but I don't know what the status of it is.

---------- Post added at 13:07 ---------- Previous post was at 13:06 ----------

:ninja:'ed by Indy

 

[indy91]

Just to explain something I thought was common knowledge around here. Or maybe you all are playing along and I don't get it? I'm German, that would be my excuse. :rofl:

NASSP (http://nassp.sourceforge.net/wiki/Main_Page and/or https://github.com/dseagrav/NASSP/ ) uses the Virtual AGC emulator (http://www.ibiblio.org/apollo/index.html), which runs exactly the code described in the OP. At this point it is fully implemented in our simulation of the CSM and essentially the LM too, but the LM doesn't properly work right now.

I don't use the word "fully" lightly, we have the AGC connected to all the necessary simulated systems (IMU, RCS, sextant, attitude indicators etc. etc.) so that all the capabilities of the AGC can be used.

And just to give a little status update about the state of development of NASSP, we have made a lot of progress in the last few months. At this point all major features that we want for the "infamous NASSP 7.0 release, many years after the last one" are implemented. A bunch of people are working on documentation right now and lots of tweaks and fixes will have to be done in the next few weeks/months/I hope not years, but it's heading in the right direction. NASSP can probably learn from SSU and slightly lower expectations for what a "release" has to be able to do.

 

[Andy44]

Basically you'd have to write an emulator of the hardware used to run the code on... That would be quite a project, but there are people here that might be crazy enough to attempt it.

Or you could build an actual AGC clone out of mail-order electronic parts.

Somewhere around here I saw a video where some guys built a clone of an early processor chip out of discrete transistors on a hand-soldered circuit board. Because of its size the clock speed was slower but it works.

I've not seen a schematic for the AGC but if you're ambitious enough, anything's possible.

Of course, once you've built a working bench model of the AGC, you now have to build emulations of the subsystems it's supposed to interface with.

And then you install it all in your sim pit.

And then you simulate the sun, earth, and stars with moving lamps on the outside of the sim pit for your emulated sensors to interact with, and the lamps have to be controlled by the sim software...endless fun! :tiphat:

 

[Urwumpe]

Basically you'd have to write an emulator of the hardware used to run the code on... That would be quite a project, but there are people here that might be crazy enough to attempt it.

Or use LLVM to JIT it.

 

[Matias Saibene]

https://github.com/chrislgarry/Apollo-11/

Do you think Orbiter devs could use this for addons?

Burkey reconstructed the unreadable parts, he said, using his engineering skills to fill in the blanks...

“Quite a bit later, I managed to get some replacement scans from Gary Neff for the unreadable parts and fortunately found out that the parts I filled in were 100% correct!” he said.

100% seriously?

And there they go, ladies and gentlemen, 20 years of research and Internet crowfunding:

 

[Ravenous]

Apparently someone with no knowledge at all about aerospace has already been on there and tried correcting the obvious spelling mistake of "Attitude" to "Altitude".

Kids these days...

(Oh, and at last I've got around to looking through the now famous program "BURN_BABY_BURN--MASTER_IGNITION_ROUTINE.s")

 

[Col_Klonk]

Looks similar to PIC (Atmel.. small cpu) assembler code - that's if it was used that is.
Somebody will take the time to go through it and come up with a 'known revelation'

 

[Ravenous]

Looks similar to PIC (Atmel.. small cpu) assembler code - that's if it was used that is.
Somebody will take the time to go through it and come up with a 'known revelation'

Well straight away I looked and there's the 1201 and 1202 alarms in there. (though I can't tell what's actually happening at that point.)

A brief look through was interesting - we programmers have it easy these days!

 

[Quick_Nick]

My favorite bit:

 

[Capt_hensley]

If you're serious about simulating the parts of the craft, use load banks and servo's with micro-switches as sensors. This was done many times within the aerospace community when hardware was too expensive or inconvenient to build. For this stuff it's no longer rocket science, it's pseudoscience.

Many of the specifications can be found in the published engineering drawings, from o-scope readings, to simple feedback loops. It's all about flow and resistance. Even strain gauges, and accelerometers are cheap and easy to get.

But I'm no rocket scientist, nor engineer.

 

[Col_Klonk]

But I'm no rocket scientist, nor engineer.

Ahhhh.. an Armchair Expert talks sense once again :thumbup:

 

[indy91]

There is a tutorial for building a Block 1 AGC: http://klabs.org/history/build_agc/ Good luck with that. :lol:

My personal (guess why) favourite Apollo hardware building project though is a DSKY, that directly connects with the Virtual AGC in NASSP:

Obviously it runs the emulator and not actual AGC hardware, but still pretty nice.

 

[Messierhunter]

My personal (guess why) favourite Apollo hardware building project though is a DSKY, that directly connects with the Virtual AGC in NASSP: Apollo Guidance Computer DSKY - YouTube

Obviously it runs the emulator and not actual AGC hardware, but still pretty nice.

Is the guy who made that a poster here? I'd be very interested in learning how he did that.

 

[indy91]

Is the guy who made that a poster here? I'd be very interested in learning how he did that.

Not sure if he is here. It's Hitman57 on the French Orbiter forum (http://orbiter.dansteph.com/forum) and Hitman458 on the Meadville Space Center forum.

I know he had to change some things in NASSP, because this isn't natively supported. Mostly he had to revert some changes about the Virtual AGC implementation. Maybe the relevant thread is helpful to you: http://www.ibiblio.org/mscorbit/mscforum/index.php?topic=2889