This is our collection of all the documentation we've managed to gather over the decades that bears even a passing relevance to the spaceborne guidance computers used in the Apollo and Gemini programs ... or at least all of the documentation I think I'm legally able to give you at the present time. Some hints as to where to find such documentation on your own can be found on our Documentation Quest page. Our FAQ page also points out various significant Apollo-centric websites from which we've taken some documentation, in order to centralize it.

When we're in possession of high-resolution scans, it's our practice to provide only a reduced-quality but legible version here, but to provide the full resolution data at our Internet Archive site. On this page, the links for both are provided. In general, when any given document has multiple hyperlinks listed, the first of the links is the recommended one, and the second or third links provided are generally either much larger downloads, or else are much lower quality scans.

Finally, while the available documents are provided below in a form which we think is relatively convenient, we also usually have more information than we care to clutter up your screen with. For example, we have the sizes of the downloads, and sometimes the names of the archives from which we extracted the documents, as well as the name of the person who either did the scanning for us or else financially supported the scanning process. You can see this supplemental information by hovering your mouse over the document title's hyperlink before clicking the link. Similarly, if you hover the mouse over a document number or an author name, that's highlighted as shown here, you may be able to find out the organization that produced the document or with which the author was affiliated. Unfortunately, this extra pop-up information only works if you have a mouse rather than a touchscreen, since you can hover a mouse cursor but not a finger; but that's life!

Table of Contents

Recently Added Documents (09/14/2021)

This section lists all documents updated in the last 3 months. Note that recently-added G&N engineering drawings are not included in the list.

Added 09/14/2021 Added 09/13/2021 Added 09/08/2021 Added 09/07/2021 Added 09/06/2021 Added 09/05/2021 Added 09/04/2021 Added 09/03/2021 Added 09/02/2021 Added 09/01/2021 Added 08/31/2021 Added 08/13/2021

Presentations

Presentations from the MAPLD '04 conference, by AGC developers and other knowledgeable folks.

Guidance System Operations Plans (GSOP)

The items below are arranged by MIT Instrumentation Laboratory document number.

Space Guidance Analysis 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 Project Memos

Apollo Engineering Memos

Digital Development Memos

These memos primarily relate to the electrical design of the AGC.

Electronic Design Group Memos

Inertial Sub-System (I.S.S.) Memos

XDE Notes

These are notes from AC Spark Plug Division, commenting on topics peripheral to the AGC, such as ground-support equipment.

Digital Group Memos

Mission Techniques Memos

System Test Group Memos

LUMINARY Memos

The "LUMINARY Memos" are internal memos from the MIT Instrumentation Laboratory dealing with issues of LUMINARY software development, along with closely-related software branches such as ZERLINA.

Of particular interest, if you're concerned with the evolution of the AGC software, are the many memos used to document the changes of the LUMINARY code from one revision to the next. In theory, if you had all of them, you could come pretty close to using them to document the complete evolution of LUMINARY, or at any rate from LUMINARY 4 (memo #22) through LUMINARY 209 (memo #205).

But back to the memos. Over 250 of them are known, of which we've gotten the majority from Don Eyles's personal collection. The items which are grayed-out relate to memos about which we have some information but not the actual memos themselves.

COLOSSUS Memos

SKYLARK (SKYLAB) Memos

Program Change Requests (PCR) and Notices (PCN)

Program Change Requests (PCRs) were the official mechanism by which proposed AGC software changes were submitted to the NASA Software Change Board (SCB) for approval or rejection. I'm not sure what the distinction between a PCR and a Program Change Notice (PCN) is. Visually they're essentially the same thing. In any case, the signficance is that since AGC software changes were governed by them, knowledge of the PCRs/PCNs is of tremendous importance in tracking changes between LUMINARY and COLOSSUS software revisions ... or alternatively, of no importance whatever if you're not interested in understanding the evolution of LUMINARY and COLOSSUS.

The entries below are arranged by PCR/PCN number.

Software Anomaly Reports and Assembly Control Board Requests

In this section, we cover Assembly Control Board Requests and MIT/IL Software Anomaly Reports. These seemed to act similarly to PCRs and PCNs respectively (see above), and except that for some reason approvals could be made by a local board at MIT/IL rather than by the higher powers at the SCB.

These documents have no titles as such, so the titles given below are actually portions we've extracted from the descriptions of the problems described by the documents.

The entries below are arranged by publication date.

Abort Guidance System (AGS)

The entries in this section are sorted by publication date.

Launch Vehicle Digital Computer (LVDC) and Friends

We have precious little LVDC documentation, and even less LVDC software. The Wikipedia article on the LVDC at the time I first wrote on this subject lamented that all of the LVDC software has probably vanished and does not exist any longer. Fortunately, that has turned out to be false, although there may be enough truth in it to make us very uncomfortable.

The entries in this section are sorted by publication date.

Engineering Drawings

There is one significant category of Document Library items which cannot be contained within the format of this web page. I refer to electro-mechanical drawings of the CM and LM G&N systems. For example, the AGC circuit schematics or the drawings of the physical design of the DSKY. While a few of those drawings appear here, the truth is that the totality of G&N electro-mechanical drawings in our collection outnumbers the mere "documents" found here by about 100-to-1. And you can't "browse" through hundreds of thousands of engineering drawings the way you can with a mere few thousand documents. Instead, you have to go to our Electro-Mechanical Page, which provides you with two very-valuable resources to find the engineering drawings you need:

Everything

If none of the sections above coincides with your special interests, this section may help. It contains every item in our Document Library, whether or not those documents were already included in the preceding sections. (Excluding, of course, G&N system engineering drawings, as covered in the immediately-preceding section.)

If you still can't find what you need after you've looked in this section, you might consider using the Google searchbar that appears near the top of this page. It has the great advantage of searching not only document titles, document numbers, and authors, but in fact does a complete search of the text within the documents ... and not only here on this Document Library page, but for all pages on the Virtual AGC website. Alas, the optical character recognition (OCR) process that creates the text index is not perfect, so your search may still fail even if the document you want is present. But then, what is perfect in this old world?

The entries below are sorted by publication date. Items whose publication date is unknown appear at the very top of the list.