Here you'll find a collection of all the AGC, AGS, LVDC, and Gemini spacecraft computer documentation and software that I've managed to find whilst working on  Virtual AGC.  Every document on this page is archived here at Virtual AGC, regardless of whether it originated here or not.  In the early days I used to include only material I uncovered by my own efforts, but there have increasingly been contributions by readers, including some of the original AGC developers.  And there's material here that has been duplicated from other Apollo-centric websites for your convenience; see the FAQ page for a list of the fine Apollo and Gemini websites I raided. Now, there is some value-added in this process, since I add searchable text to those PDFs which are image-only, as well as adding metadata and bookmark panes where they don't exist.  My intention is to eventually provide one-stop-shopping for all of your Apollo and Gemini computing-system documentation needs. Note however, that I choose to duplicate only scanned or photographic images of the original documents.  In other words, I provide something as close to the "real thing" as I can.  On some sites, notably the Apollo Flight Journal and Apollo Lunar Surface Journal, great pains have been taken to produce HTML forms of the documents.  I do not duplicate those improved reformulations here, because that's original work for which I think credit is due; so you will have to visit those sites to use those improved versions.

Document categories

AGC-related presentations

Various presentations presented at the MAPLD '04 conference, by AGC developers and other knowledgeable folks

 AGC software manuals and listings

Guidance System Operations Plans (GSOP)

AGC quick-reference cards or data cards

AGC pad loads

AGC electrical schematics

Regarding the Block II AGC schematics, I have heard that there is a general attitude that they are incomplete, which is true, and therefore inadequate for allowing one to construct a hardware simulation of a Block II AGC, which is probably not true.  Mike Stewart, who has in fact built such a hardware simulation, assesses the adequacy as follows (in slightly edited form):

[It depends] on what is meant by "complete". The logic and interface modules are all present, so working simulations/replicas of the *logic* of the computer, and its connections  to the outside world, are certainly possible ...

That being said, there are missing pages, which make it more difficult (and less accurate/"complete") than it needs to be. All of them are in Tray B and the DSKY.  [There is only one schematic page] for each -- the clock oscillator in Tray B, and the power supply for the DSKY (D7).

The missing modules are, to my knowledge:
Plus, any other ancillary information that wasn't done on a circuit board like DSKY button wiring, pinouts, backplane connections, and such that I can't put a number or name to.

I'd argue that none of this is strictly necessary for a "complete" simulation. Nobody's going to weave their own core/core rope memory anyways... there's tons of ferrite cores on ebay. I did the math. It would take years. So that immediately drops the need for B9-10 and B13-17. It's possible to implement your own versions that respond only to the signals fed directly to those modules (ie without cheating), which is how mine works.  ...

The alarms module stuff can be done custom to the application, or without the filter (FLTIN connected straight to FLTOUT), or whatever.

There are enough partial drawings of the indicator driver module that you can cobble something reasonably close to the real thing together, albeit with probably different relay decoding wiring (though there's less correct answers to this than many seem to think) and component values.

THAT BEING SAID, as somebody trying to build a replica that's as accurate as possible, all of these and any other electrical/mechanical drawings are now at the top of my want-list.

Space Guidance Analysis (SGA) memos

If you are interested in the mathematical underpinnings of the AGC software, then this amazing series of memos from MIT's Instrumentation Lab is the place to look.  The memos are in roughly chronological order.  It is very interesting to reflect on the fact that these mathematical memos are often written by the very same people whose names you find as authors in the software.  The AGC software was written in a time ... or at least a place ... where software was regarded as the expression of mathematical knowledge as opposed to being a mere exercise in the expert employment of programming languages and tools as it is today.  It is interesting also to reflect on the nature of the software this approach produced.

Apollo Experience Reports

Miscellaneous Guidance & Navigation

These items are alphabetical by author.  (Where the "author" is an organization rather than a person, I consider the author to be "Anonymous".)  These items are mostly documents are from our (improved) archive of the now sadly defunct AGC website of MIT's Dibner Institute for the History of Recent Science and Technology.  (Yes, there is some duplication here, but otherwise it becomes all too easy to lose documents because they're smeared across multiple web-pages.)

Abort Guidance System (AGS) and its computer (AEA)

As inadequate as our AGC documentation collection is, our AGS documentation collection lags far behind.  All of the available documentation was digitized by John Pultorak from physical documents preserved and donated by Davis Peticolas.

Launch Vehicle Digital Computer (LVDC)

We have precious little LVDC documentation of any kind, and no LVDC software at all.  The Wikipedia article on the LVDC laments that all of the LVDC software has probably vanished and does not exist any longer.  Well, I don't believe that.  (They're smart enough to send a man to the moon, but too stupid to put the documents in a file cabinet afterward?  I hope not!)  There must be some former LVDC developer somewhere who was proud enough of his work to retain some souvenirs.  If you know any LVDC developers, please help us to get in contact with them.

Systems Handbooks

Operations Handbooks

Operational Data Books

Technical Crew Debriefings

Mission Reports

Flight Plans


Familiarization Manuals

General Apollo documents unrelated to computing systems

Press Kits and Releases


Gemini spacecraft computer

Last modified by Ronald Burkey on 2016-12-30.

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