This repository contains downloadable Autodesk Fusion 360 and STEP CAD models of many Apollo Guidance Computer components.
The Apollo Guidance Compuer (AGC) is one of the critical inventions that made the U.S. moon landings possible. AGC's were installed in both the Apollo Command Module and Lunar Excursion Module. MIT and NASA archives, as well as important contributions from some of the original team members have given us a rich set of detail about how this computer was constructed.
The Virtual AGC Project was originally focused on software simulation of the AGC.
Over time, the Virtual AGC Project branched in many directions. Simulation projects for other space related guidance systems were researched; hybrid hardware and software models of the AGC have been created. The circuitry of the AGC has been reproduced using modern IC components.
More recently, Ron Burkey, the Virtual AGC project's leader, scanned, cataloged, and published the original MIT electrical and mechanical drawings of the AGC. This detailed catalog has made it possible to construct CAD models of the AGC's mechanical components.
The content in this repository represents my work using Fusion 360 to generate CAD models from those original drawings using modern CAD/CAM tooling.
Autodesk's Fusion 360 was used exclusively to create these models. While Fusion 360 is not open source software, Autodesk offers a no-cost license to students, makers, and startups. You can obtain your own copy of Fusion 360 and begin editing the .f3d files contained in this project. STEP-format CAD models for each component have been exported and included in this project as well. Those model files are directly usable by many other CAD modeling and 3D-printing systems.
Panel markings use an engraving font face called "Gorton". Eugene Dorr created OTF and TTF versions of these fonts. These files can be downloaded from https://github.com/ehdorrii/dsky-fonts
It is worth saying that the source archives for this project are incomplete.
The AGC evolved substantially over its lifetime -- descriptions of many changes
are captured in Engineering Change Proposals (ECPs) which may or may not be completely
reflected in the archived drawings. Also, there are gaps in the drawing collections.
This requires reconstruction of some parts in order to develop a more complete model.
No. I am releasing what I have transcribed so far. That amounts to roughly twenty models. Each is currently 90-100% completely encoded from the original engineering documents.
I'm working to maintain engineering precision wherever I can. Errors undoubtedly exist, and I'm my own Quality Assurance department currently. In other words, use at your own risk.
An example illustrating the resources and gaps we work from is the DSKY pushbutton switch. There are three distinct part numbers representing different variants of the pushbutton switch: 2003875, 2003894, and 2003984. Of those three only 2003875 has a mostly complete set of drawings.
The gap starts with the cap housing assembly. The cap housing sits behind the actual key cap. It holds the cap in place and serves to guide the depressed key into contact with the actual switch. The drawing for that cap housing assembly is - so far - missing. Also missing is a drawing for the leaf spring that's mounted at the back of that assembly. There's a rivet attaching the spring to the housing, too. The exploded drawing you see above represents a best guess of the dimensions of the missing parts.
On my to-do list for this project is to build a compendium of what parts we have, where we had complete drawings to work from, and where the gaps and guesses are.
This Raytheon contractor report describes important upgrades to the DSKY that are not completely captured in the archived drawing collections:
h. DSKY pushbutton switch spring - Due to failures of the DSKY pushbutton switch spring (shown in Figure 3-6) a failure analysis and design review of the spring was performed. The failure inalysis and design review indicated that in normal use the spring could crack at points of stress concentration. As a result, a new spring was designed. As shown in the drawing, the new spring replaces the present spring in form, fit, and function with tighter geometric constraints.
The wraparound design of the new spring lengthens the spring arm to reduce stress and allows the new spring to be incorporated in the existing pushbutton switch design. The thickness of the spring has changed from 0.010 to 0.018 inch to retain the same spring rate. The material of the new spring is the same as that for the present spring but is specially hardened to a minimum of 270,000 lbf/in^2 U.T.S. to increase the fatigue strength of the spring.
i. DSKY fire fix - As a result of the flammability study performed as authorized by CCA 497-0428, the DSKY alarm indicator(P/N 1006387-003) and DSKY pushbutton caps (P/N 1006353) requiredmaterial changes as follows (see Figure 3-7)
- alarm indicator - affix nonflammable nonreflective glass cover with an aluminum frame as an integral part of the indicator panel
- DSKY pushbutton caps - rep:ace the acrylic cap with one of aluminum having etched and acrylic filled characters.
j. Teflon - (not included here, as it dosen't directly apply to the Fusion CAD models, but Teflon coatings were added to reduce the tendency for pushbuttons operate less smoothly due to wear.)
These changes are listed here but not yet integrated into this CAD project.
My name is Riley Rainey. I'm a software developer by profession. I spent a number of years building aerospace simulations as my day job. I'm not a Professional Engineer by any stretch, but my work in simulation put me in close contact with CAD designers and CAD systems. I used AutoCad many years ago, but my exposure to Fusion 360 began with this project.
There's no official support available, but if you notice a problem or have a request for a specific drawing to be transcribed, create an issue in this GitHub project.
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
