Actually, there are a lot of Luminary program versions we don't
have, and won't ever have. Thus, the reason Luminary 99 is
called 99 is because of the 98 versions preceding it, all of which
have now vanished with the wind ... we presume. The same
goes for the documentation associated with the software, so we
only have incomplete snapshots at various points in time, and in
the table below I've made an effort to associate important
version-specific documentation with the software version.
However, in case of Luminary, we have an additional very important
resource that I haven't bothered to link in on a version by
version basis, but which you can nevertheless consult. I
refer to the so-called LUMINARY
Memos, a collection of 250+ internal Instrumentation Labs
covering many aspects of the Luminary development process,
including extensive descriptions of revision-to-revision
changes. Instead of trying to isolate which memos are
specific to which of the many program revisions, I'll just
recommend that you browse the memo collection yourself as you see
|Mission||LM Number|| Mission|
|LM Program||Version||Source Code||Mission-specific documentation||What We
Know About It, in a Nutshell|
Reduced-size scanned JPG
High-quality scanned JPEG 2000
|N/A||As you've seen elsewhere on this
site, there where two major versions of the AGC, the Block I
and Block II models. While there was never any Block I
code for the Lunar Module, as far as I am aware anyway,
there was certainly Block I code for the Command Module, and
at some point a transition was made both from writing Block
I code to writing Block II code ... but also from writing CM
code to writing LM code, and Retread marks that transition
point! It's the veritable Missing Link of AGC code,
which is particularly a propos since in fact the YUL
development system employed for AGC development didn't sport
a linker. (Joke! Feel free to ignore.)|
In other words, Retread was when Block I code for the CM began to be adapted into Block II code for the LM. Thus, like Aurora below, Retread was never intended to be mission code, and was never flown. But it has the honor of being the "first" LM software. It is, in fact, more than a year older than any other AGC software of any kind (Block I, Block II, CM, LM) available publicly at the present time, as far as I'm aware!
Indeed, if you look at the date on this software — I'll save you the trouble; it's July 9, 1965 — that's the same time (within a month or two) of when the first Block II AGCs were actually becoming available, and thus the only way to have run RETREAD at that time was probably in a digital simulation. But of course, digital simulations in advance of actual hardware are never perfect, so there would be every possibility that RETREAD 44 may not be exactly compatible with Block II AGC hardware yet ... and it turns out that that's the case. If, for example, you look at the self-check code, run by VERB 21 NOUN 27 ENTER 1 ENTER, not all of the CPU tests pass! (There is a detailed write-up of this issue, if you're interested.)
At any rate, this particular program listing came to us from Don Eyles, via scanning at archive.org, financially-sponsored by Mike Higgins.
Reduced-size scanned JPG
High-quality scanned JPEG 2000
|N/A||Don Eyles, one of the AGC
developers who you may know as the hero of
Apollo 14, has contributed the hardcopy of this
program from his personal collection. We have had it
scanned by archive.org,
and Mike Stewart has generously financially-sponsored the
scanning. So, thanks Don and Mike! As usual, we
provide it here in the form of reduced-size (but therefore
reduced-quality) images for easier access, but the original
scans in their full quality are still available in our
Virtual AGC collection at archive.org.|
I suppose I should mention that if page 52 or 70 of the reduced-sized images look a little weird to you (oh, you conspiracy theorists with your Photoshopping theories!), I should mention that those were places where there was a paper-change on the printer, and I simply glued two partial pages together to make it look pretty. You can look at the high-quality scans to see all of the pages in their original, un-Photoshopped glory, if you like. There are also a couple of pages (622 and 623, I think), which are missing right now, but which archive.org should add within a couple of days of when I'm writing this.
Now before you go all elitist and thumb your nose at Aurora just because it never flew on an actual mission (even an unmanned one), let me tell you that from this project's standpoint it is quite a terrific find. For one thing, it employs unique flavor of the AGC programming language; although it is a Block 2 program for a Block 2 computer, the language version precedes its final form as used in the later software versions we have available, requiring changes to the assembler just to assemble it. Technically, it was targeted at the "BLK2" software architecture rather than the "AGC" software architecture.
More significantly, it was the last version we know of to incorporate the full range of AGC testing software that had been created. In actual mission software, most of this testing software was removed due to size constraints, and due to the fact (I presume) that most of the tests were more-appropriately done in the lab, as acceptance tests, rather than in space where nothing could be done about the failures anyway. Why do we care about that? Well, how do you think we test the AGC simulator anyway? Pre-Aurora, our only choice was to roll our own tests, which the original AGC may not have even been able to pass for all we know. But now that we have Aurora? Well, we haven't yet converted it to source code, and couldn't assemble it yet without modifying the assembler to accept this flavor of assembly language anyway, so it's too early to say. But once we do that, we hope that some lingering bugs in the simulator will be ferreted out, as well as to give us additional confidence in the simulator. It's also a boon to developers of hardware AGC simulations, like Mike (who sponsored this), because they would like to validate their own simulators just as we would.
Finally, there's something of a mystery associated with Aurora 12. The hardcopy we have of it is from November 10, 1966, and Aurora at the point should have had a version number in the 80's. How could it be version 12? Perhaps one day we'll know!
Reduced-quality PDF (160MB)
High-quality scanned JPEG 2000 (400MB)
SUNBURST rev 37, otherwise known as SHEPATIN rev 0, is an
early revision of the SUNBURST program, not used in any
mission. The scan was taken from Don Eyles's personal
copy, for our Internet Archive collection, and financially
sponsored by Peter McDermott.|
I would hazard the guess that SHEPATIN was a program Don used for off-line development of new program features or bug fixes for SUNBURST, and that SHEPATIN 0 happened to have been branched from SUNBURST 37 ... thus it is a "clean" copy in which no changes had yet been made, which fortuitously (for us) gives us a nice snapshot of SUNBURST development as well. We know that SHEPATIN was developed at least through SHEPATIN 6, since the notes at the end of the AURORA 12 assembly listing mention assembly of SHEPATIN 6. At any rate, whatever the exact history, we're obviously we're thrilled that Don saved it for us.
SUNBURST 37 is substantially different from SUNBURST 120 (see below), used later for Apollo 5, and thus, like RETREAD and AURORA (see above) is a kind of missing link in the evolutionary chain of the AGC software in general and the LGC software in particular.
|Apollo 5||LM-1||Sunburst||120||As colorized,
Reduced-size scanned JPG
High-quality scanned JPEG 2000
| GSOP (R-527)|
Apollo Experience Report—Guidance and Control Systems: Lunar Module Mission Programer"
"LM-1 Trip Report at MSC - Flight Support and Debriefing"
"Results of Independent Flight Software Validation Test of the BURST116 Program for the LM-1 Mission"
|Apollo 5 was an unmanned mission to
test the LM, and as such it had a working AGC, though at
certain points in the mission the ground controllers
bypassed the AGC (which hadn't been planned for), using the
AGS instead for some
maneuvers. The mission itself was not entirely
The "Programer"—actually some sources spell it "programer" and some "programmer"—was a robotic gadget that was the stand-in for the crew.
Don Eyles provided the hardcopy for our the program-listing scan we present here. It was scanned by archive.org, and was generously sponsored by Mike Stewart. The original printout unfortunately has some problems in the vicinity of pp. 820-830, but we naturally correct those in our transcription.
The LM-1 Trip Report was provided by its author, AGC developer Jay Sampson, and provides a fascinating blow-by-blow description of what transpired during the actual mission, and a summary of the subsequent debriefing.
In spite of the relative lack of resources about the Apollo 5 mission, NASSP developer and enthusiast Niklas Beug tells us that
... we have successfully been able to fly most of the Apollo 5 mission with that scenario, including two burns with the Descent Propulsion System and one with the Ascent Propulsion System. As you know, during the actual Apollo 5 mission Sunburst didn't actually make it beyond the first DPS burn due to slow thrust buildup and a resulting thrust fail indication. But in NASSP Sunburst has been able to complete the simulated DOI, and the simulated powered descent with a late abort and staging, followed by a short APS burn.Recall that NASSP is an Apollo-mission add-on for the Orbiter spaceflight simulator that integrates our AGC simulator so that it can run the actual AGC software to control the simulated CM or LM. The "scenario" Nik is referring to here is, of course, using SUNBURST 120 in a simulated LM, but it also involves the trickery employed to account for the fact that we have no documentation for the pad-loads needed for this mission. What Nik did to generate these pad-loads is very interesting, so I'll quote him in full:
[In NASSP], we can't currently have a running simulated Lunar Module on the launchpad, due to how NASSP simulates the CSM and Saturn vehicles as one entity. But nothing was stopping me from creating the usual padload worksheet for Sunburst120. Luckily there were a few resources available for that, including the "Prelaunch Erasable Memo Load Definition for AS206" document.
|N/A||N/A||N/A||Super Job||N/A||As colorized,
Listing in Appendix D of Volume 2 of Raytheon document R68-4125
R68-4125, volume 1, "Final Report: Auxiliary Memory for
Apollo Guidance Computer"|
Raytheon R68-4125, volume 2, "Final Report: Auxiliary Memory for Apollo Guidance Computer"
E-2254: "Auxiliary Memory System, Final Report on Phase I"
|This program, Super
Job, is a very unusual offering, in that it is AGC code not
written by the MIT Instrumentation Lab, but rather by
Raytheon. Of course, sub-contractors from Raytheon,
A.C. Electronics, and others, were used to help write the
"regular" AGC programs as well, but this program is entirely
written by Raytheon. |
Nor does it seem to have been assembled with the YUL or GAP assemblers used to assemble all of the other AGC code, but rather (as far as we can tell!) an in-house Raytheon assembler. That in-house assembler is almost, but not quite, compatible with YUL/GAP: slightly different address formats were used, and the interpretation of certain operands is slightly different. We support that with a special command-line switch (--raytheon) in yaYUL.
The way this program came about is that Raytheon was contracted to do a feasibility study for potentially expanding the AGC memory capacity by adding a magnetic-tape recorder. If you have looked at our Gemini OBC (on-board computer) page, you'll know that the later Gemini missions did use a tape-memory unit to load different OBC software for different mission phases, and this is a similar idea. The basic characteristics of the auxiliary memory were:
The auxiliary memory was never used in a mission, so you
may suppose it was a completely-obscure feature, but there
is actually some measure of legacy support for it, albeit
very trivial, in every LM code version from Sunburst
onward. The way its effect is seen is that the AGC's
so-called "superbit"— the flag in the memory-bank register
that selects memory banks 40-43 vs banks 30-33 — actually
consists of 3 bits even though single bit is needed.
The extra two superbits would have been used to select the
various auxiliary-memory functions mentioned above.
Actually, the story I've been told (by MSC's Clark Neily) is that there was an intense dispute (which he labeled The Rendezvous Wars) between the optical camp (led by Max Faget) and the radar camp. You can read Clark's extended comments about it in our document library. The radar camp won for Apollo, but lost for the shuttle. Such is life!
At any rate, Super Job is a test program for this tape-drive system. While we provide the transcribed source code for SuperJob, it's probably not too useful to run it in the AGC simulator as of yet; probably the tape drive itself will have to be simulated as well, perhaps with a new program that might be named yaTape. Or not; we'll have to wait and see. It's also worth noting that the scanned program listing is rather wimpy in places, and has no niceties such as memory-bank checksums to give us confidence that the transcription of the source code is correct ... but we hope (and think) it probably is.
And finally, as you may have realized, there is actually no logical reason for including Super Job here on the Luminary page. There's nothing in the documentation suggesting that it would be installed in the LM vs the CM. Rather, it's just a generic concept that might apply to either spacecraft, or to both of them. But it has to go somewhere, so here it stays!
Apollo 9|| LM-3|| D|| Sundance||306|| || GSOP (R-557)|
LM Digital Autopilot Study Guide, Sundance 302
| Here is some info from James
Kernan, one of the LGC developers, in response to my
question about correct versioning of Sundance:|
Sundance 306 is correct. I was the "rope mother" for Sundance-Apollo 9. ... Sundance was not only the Apollo 9 LM flight program, it was also the development bed for the Lunar orbit and landing software. At some point we created a version and called it Luminary. I think the last few revisions of Sundance were devoted to disabling crew access to the Lunar orbit and landing software that was present in the build.
Jim also tells me that a copy of Sundance 306 may still "be in the building". I'm not certain which building he's talking about, but it's nevertheless interesting news that a copy of the program does exist somewhere.
Apollo 10|| LM-4|| F|| Luminary 1||069/2||As colorized,
Reduced-size scanned JPG
High-quality scanned JPEG 2000
| GSOP (R-557)||The version we have here is from Don
Eyle's private collection, as scanned by archive.org, and
financially sponsored by our Onno Hommes.|
Actually, though, it may not be quite the version actually flown on Apollo 10. As it says right at the top of every page, it is REVISION 069 OF AGC PROGRAM LUMINARY BY NASA 2021112-011, whereas it is known that the version flown on Apollo 10 was Luminary 69 Rev. 2, 2021112-031, which was released five months later. Such last-minute changes were often the result of ephemeris upddates or other time-sensitive data that had to be specific to the launch window, but we don't know this for sure at the moment.
Regardless, this is the closest thing to Apollo 10 mission software we have, or are likely to find, so beggars can't be choosers!
|N/A||N/A||G||Luminary 1A||099/0||As colorized, hyperlinked, HTML||One of the original AGC programmers, Allan
Klumpp, kept a copy of Luminary 99 Rev 0 (or 99/0 for
short), since donated to klabs.org,
having been told that it was the version that flew on Apollo
11. Unfortunately, that turns out not to have been the
case, but it's awfully close!|
We know that the program identifies itself as "REVISION 099 OF AGC PROGRAM LUMINARY BY NASA 2021112-051" in the page headings of the printouts, so from the chart at the top of this page we know that it's the revision immediately preceding the flown version. Unfortunately, we at the Virtual AGC Project have never actually had access to the Luminary 99/0 hardcopy itself, or to any scans of it. I hope some day to have it scanned, though with each passing year that seems an increasingly distant dream. Apparently, Luminary 97 was actually the first AGC software version actually targeted for Apollo 11, and thus had already been modified by the time of Luminary 99/0.
As it turns out, our Mike Stewart (thanks Mike, and Nik Beug who also helped out) has noticed that we have just enough info at our disposal to reconstruct the source code for Luminary 99/0 even in the absence of the program listing itself. And having reconstructed the source code, we thus get the executable octal rope for free, and can run it in the AGC simulator.
The source code reconstructed by Mike is what you see linked at the left.
A few things worked in Mike's favor in performing the reconstruction. For one thing, we already had the program version immediately following it (namely Luminary 99/1, see the very next row in this table), and a version not much earlier (namely Luminary 69/2, see the preceding row in this table). For another, in hardcopies of program listings like those for Luminary 99/1, the relatively few lines which have changed from prior versions are marked with a *, making them relatively easy to find. Finally, while Allan did not give us his hardcopy of Luminary 99/0 to scan, he did agree to look at the memory-bank checksums for us, and was kind enough to give us the checksum of the single memory bank that differed from 99/1 ... so we could easily verify that the reconstruction was very likely to be correct. Of course, one can never be 100% sure, in the continued absence of the hardcopy. But we're pretty confident that the reconstruction is accurate; admittedly, it's possible we may not have found all of the program-comment changes.
In case you're wondering, the only change between this version and the flown version (099/1) is the correction of a long-standing bug, in which a reset of the computer incorrectly reset (cleared) certain of the hardware timers, thus resulting in events that were triggered by the next expiration of those timers occurring at the wrong time.
Apollo 11|| LM-5|| G|| Luminary 1A||099/1|| As colorized,
(MIT Library printout)
As scanned page images (very big!)
(Don Eyles's "AP11ROPE" printout)
Reduced-size page scans (JPG)
Full-resolution page scans (JPEG 2000)
| Erasable pad
Excerpted LM Systems Handbook
The 1201/1202 alarms
The Apollo 11 Adventure
Operational Data Book
"Exegesis of the 1201
and 1202 Alarms Which
Occurred During the
Mission G Lunar
Digital simulations of the landing:
| This is the AGC software
version that we accept as having been flown in the Apollo 11
Page images have been taken from a hardcopy from the Charles Stark Draper Historical Collection, MIT Museum, and then converted to source code by a team of volunteers.
Below, you can see a video made by Niklas Beug, in which this Luminary 99 AGC software is used to make a simulated Apollo 11 lunar landing, using the Orbiter spaceflight simulator, with the NASSP 7.0 Apollo-mission add-on and our own AGC CPU simulator. (A higher-resolution version is probably available if you go directly to YouTube.)
The MIT Museum copy is dated 14 July, 1969, which seems odd at first glance, since it would be far too late to actually have been included in the Apollo 11 mission. AGC developer Hugh Blair-Smith speculates that this is the date of the printing rather than of the program build, and that seems plausible. At any rate, the printout identifies itself as "REVISION 001 OF AGC PROGRAM LMY99 BY NASA 2021112-061", which according to the chart at the very top of this web-page tells you that it is indeed the version that was flown in the mission ... but keep reading, because there's more to this story than meets the eye!
AGC developer Don Eyles also has a copy of Luminary 99, though oddly named AP11ROPE BY EYLES rather than LMY99 BY NASA, and it was printed in 1970 for some reason. Our scan was financed by Vipin Rathor (thanks, Vipin!) After a full analysis of AP11ROPE yet, I can tell you the following:
The 1969 digital simulation was done a few days after the actual landing. While we're not 100% sure why it was made, one speculation is that it was done in order to investigate the causes of the 1201 and 1202 program alarms that had been experienced during the landing itself. Don Eyles agrees that this must have been what he intended, and points out that his notes indicate that TLOSS (the maximum amount of CPU time that it was permissible to "lose") was set to 10% in that run. (It was the fact that the CPU time lost in interacting with the rendezvous radar was excessive that caused the Apollo 11 1201/1202 alarms. See LUMINARY Memo #140, for example, for some background information about TLOSS.)
Also, you may wonder, why was there a digital simulation of Apollo 11 in 1971, a couple of years after Apollo 11 landed on the moon? Shouldn't the simulations only have been useful before the landing? Well, Don Eyles had this simulation performed for his own purposes and (after nearly 50 years!) is no longer sure quite what that purpose was. He worked on several off-the-main branch AGC programs, such as ZERLINA (coming soon!), intended to explore improved methods for performing the landing; my theory is that this simulation provided baseline data against which to measure such improvements, and Don admits that this is a plausible theory.
Speaking of ZERLINA, if you examine the full-color scans for the digital simulation found at archive.org, you may notice that the label on the binder (removed in the B&W PDF I've posted here at this site) identifies the 1971 simulation as "DIANA Rev. 12". It is not DIANA, however: the binder containing the simulation's printout had formerly contained a copy of DIANA, we believe, and Don simply reused it for this printout without relabeling it. DIANA was another off-the-main-branch program, like ZERLINA, which was developed by Peter Adler and Don Eyles in order to explore an improved time-sharing technique that would avoid the 1201 and 1202 program alarms experienced in the Apollo 11 landing. The approach wasn't adopted, though, and copies of DIANA no longer exist as far as we know. (At any rate, neither Don nor Peter has a copy.)
|N/A||N/A||G||Luminary 1A||099/2||As colorized,
hyperlinked HTML||Here's where Apollo 11's software story
James Kernan, another of the original AGC developers, has sent us some confusing facts. I'll let Jim tell it in his own words:
I was an employee at Draper Lab, and was in charge of the Lunar Module LGC computer programming group and also in charge of Assembly Control for the flight software during the Apollo 9-12 software development period. The latter responsibility included reviewing all proposed alterations to the flight software and the YUL assembler inputs.
I can explain the confusion over the Luminary version that flew on Apollo 11. We were aiming for Luminary Revision 99 as the Apollo 11 Lunar Module flight software. There was a tradition (or rule) that the flight software version should have no revision, so we renamed Luminary Revision 099 as Lum99 Revision 0. At the last minute, Dan Lickly, our chief engineer, appeared with ephemerides updates and it took two tries to get it right. The result was that we created Lum99 Revision 1 and Lum99 Revision 2. We made a no-change version of the later and named it Lum99R2 Revision 0.
The tapes and ropes were made from that. That is my recollection. Unfortunately, I did not have the foresight to keep a printout of the flight version.
Some years later, he retells the story as follows:
The evening of the release for Apollo 11, John Sutherland and I were in the assembly control room about to make the final assembly of Luminary. For reasons unsupportable by reason, I had decided that the Luminary revision for Apollo 11 would be less than 100 and lo and behold we were about to make revision 99. The procedure for releasing a program for manufacture entailed assigning a <unique name> Revision 0 by NASA <part number>. The Revision Number had to be 0 and the author had to be NASA with the manufacture part number included. So we chose Lum99 Revision 0 by NASA <part number>. We had previously got the part number from Bob Millard in the Program Office. The LM part numbers were in the 2 million series (if I remember correctly) and CM numbers were one million. We had just made LUMINARY Revision 99 when Dan Lickly, our chief engineer, came into the room with the news that the ephemeris numbers had to be updated. This seemly upset my desire to keep the revision number under 100. But the Yul system was flexible. We changed the name to LUM99R1, and since it took 2 to get the ephemeris numbers right, the final listing is named LUM99R2 Revision 0 by NASA <part number>. So if you have a listing of what you think is the landing program for Apollo 11, look at the name, revision, and author to make sure. I did not keep a copy ( I wish I had). The mainline development of Luminary for subsequent missions continued with revision 100.Neither version of this story can be quite correct, in that it clearly indicates that one difference between Luminary 99 Rev 0 and Rev 1 is that there was an ephemeris change. However, we have both Luminary Rev 1 (099/1) and a reliable reconstruction of Luminary Rev 0 (099/0) available to us, and there is no ephemeris change between them. (See the preceding two lines in this table.) Thus, Jim is mistaken about the reason Rev 1 was produced (we know that it was a bug fix for Rev 0), and presumably it was only Rev 2 that had an ephemeris change.
But wait, if Jim is right about the rest of it (and he's quite insistent about it!), then the software version we claimed above was flown on Apollo 11 may not have been the version actually flown, since it's Rev 1 rather than Rev 2. And yet, Rev 2 doesn't match any of the documentation we've found that purports to list the flown versions! Also, the surviving digital simulations of the landing, both made after the landing itself, relate to Rev 1 rather than Rev 2. So in the end, we just don't know who is right. We can tell you that the MIT Museum version we have here (Rev 1, the preceding line in this table) can indeed be used for simulated Apollo 11 lunar landings using the Orbiter spaceflight simulator with the NASSP plug-in, without any unseemly errors occurring.
But regardless of which version actually flew, whether Rev 1 or Rev 2, Jim's story is certainly correct in one very important regard, namely that the ephemeris data in Luminary 99 Rev 1 is certainly wrong. How do we know this? Well, ephemeris data in an AGC program covers the timespan of a year, beginning on July 1 of one year and continuing through June 30 of the following year, and so the missions in the time range July 1, 1969, through June 30, 1970, should all have the same ephemeris data. Those missions happen to be Apollo 11, Apollo 12 , and Apollo 13. The ephemeris data is roughly the last 50 lines of the CONTROLLED CONSTANTS in the Luminary source code, or in this case
and it's pretty easy to see that there's a mismatch
between Luminary 99 Rev 1 and the other two. Nor, as
Jim's story would suggest, does it match Apollo
10 (Luminary 69), from the preceding 12-month
At any rate, no printout of LUM99R2 has ever been found,
nor any other reference to it other than Jim's
recollection, so we can't present you with a bunch of
scanned pages for it the way we can with all the other AGC
listings we've made available.
One thing we may be able to do is to recreate
LUM99R2 for you. You see, if the only
difference between Luminary 99 Rev 1 and LUM99R2 is the
ephemeris, and since the correct ephemeris must
agree with Luminary 116, then we can simply patch the
correct ephemeris into the Luminary 99 Rev 1 source code
... which is precisely what we've done in the source-code
hyperlink to the left! Whether it's right or wrong,
or whether it was actually flown in Apollo 11, we don't
know. But you can fly it in Virtual AGC if you like.
Apollo 12|| LM-6|| H|| Luminary 1B||116||As colorized,
Reduced-size scanned JPG
High-quality scanned JPEG 2000
LM Systems Handbook|
Operational Data Book
Spacecraft Operational Trajectory
Programmed Guidance Equations for Luminary 1B
Digital simulation of the lunar landing
E-2260: Guidance, Navigation, and Control Lunar Module Functional Description and Operation Using Flight Program LUMINARY (Rev. 116)
from the hardcopy in Don Eyles's private collection, as
scanned at archive.org (sponsored, by Ron Burkey, me).
Unfortunately, the printout is pretty faint, and pp.
217-220, 226 are entirely missing. But we've worked
around the missing pages and have been able to completely
Regarding the Programmed Guidance Equations document hyperlinked at the left, it is an MSC document whose purpose is "to provide more effective identification and analysis of various program performance features and to permit more effective review of published computer program documentation". In other words, while it does contain material related to guidance equations, it is perhaps better to think of this as being a pseudo-code description of the Luminary 116 program.
The digital simulation of the landing, from Don Eyles's personal collection (with scanning financially sponsored by Matthew Fite), had been made a few months after the Apollo 12 landing itself. But why? Surely, the simulation is useful only before the landing? Niklas Beug has researched the matter, and has noticed that a couple of the pad-load settings (namely TCGIBRAK and TCGFBRAK) in the digital simulation are a bit puzzling. What these tricky pad-load values do is to prevent the time-consuming computation of the matrix for converting between the coordinate system of the Inertial Measurement Unit's stable platform and the coordinate system of the landing site from occurring within P63. This is fine because the stable platform is aligned (by the astronauts) with the landing site reference frame before the approach occurs, so the two coordinate systems are one and the same. The Apollo 12 software, then, was used for testing that this would work simply because it was coincidentally the most-current software revision at the time, and not because the digital simulation had anything to do with Apollo 12 as such. And Niklas has actually performed a simulated landing with these pad-loads to insure that it can be done. Admittedly, Don Eyles isn't particularly receptive of this explanation, so the conclusion remains in doubt.
As far as document E-2260 is concerned, its preface say the following: "The purpose of this document is twofold. The first is to provide a functional description (operationally oriented) of the LM GNCS hardware and software and the interfaces with other spacecraft systems. The level of detail is that required to identify and define telemetry outputs. Also included are function flow diagrams of the LUMINARY programs and routines together with lists of verbs, nouns, option codes, and checklist codes for this flow. The second purpose is to provide the operational procedures for this hardware and software including nominal airborne condensed checklists, malfunction procedures, and program notes."
| Apollo 13|| LM-7|| H-2|| Luminary 1C|| 131A/1|| As colorized,
Scanned page images from HRST (very big, very poor quality!)
Scanned page images, Don Eyles (very big, medium quality!)
Scanned page images, Don Eyles (very very big, good quality!)
| GSOP (R-567)|
Excerpted LM Systems Handbook
Operational Data Book
| Unfortunately, the version we have
here is not quite the version flown in Apollo 13,
though for many years we thought it was. Niklas Beug
was sharp enough to notice what I was not, namely in the
table from document R-700
shown at the top of this very web-page that what we
have is the first version (December 1969) of Luminary 131,
but that subsequent versions were released in January and
February 1970, and it was the latter of which that was
flown. Well ... we have what we have, and not
necessarily precisely what we'd want to have in an ideal
In the early years of this project (2003-2016), we relied on a scanned PDF of Luminary 131 that had appeared on the now-defunct History of Recent Technology (HRST) website. We're not entirely sure of the history of that scan, though there is a great cover letter from original AGC developer Jim Kernan that goes with it. What we are pretty sure of is that David Craig, apparently a great collector of AGC artifacts, asked for an AGC program listing, got this one (possibly xeroxed by Hugh Blair-Smith according to one theory), and that Gary Neff scanned it, passing the scans along to the HRST website administrators. Unfortunately, the image quality became severely compromised after that point ... but whatever the image quality, we have to be grateful to all of these folks, because it was really the existence of this scan that made our entire Virtual AGC project possible. Thanks, guys! Gary Neff also later kindly provided me with a replacement for a page which is garbled in the HRST version. This original scan is still available, linked at the left as "Scanned page images from HRST".
Nevertheless, however grateful we may feel for the HRST version, we're luckier today to have an infinitely superior scan, made for us from the personal collection of AGC developer Don Eyles, and scanned for us by archive.org. A few pages (1728-1734) happen to be missing from Don's copy, and I've simply inserted them from the HRST copy.
Finally ... we can tell that these two different scans actually came from the same physical copy. This makes sense from Jim Kernan's cover letter to David Craig, which says that Don Eyles supplied it. However, if you try to check the scans for the hand-written notes that appear on many of the AGC listings, you soon realize that the HRST version doesn't have the notations that the Eyles version has, which is at first blush is impossible from the same printout! Well, if you're persistent enough, you do eventually find notations that appear on both of them. (Look on page 750.) So the conclusion must be that Don (or somebody) wrote in most of these notes after the HRST version was copied in 1991, rather than during the actual Apollo project. Isn't that nice to think that the program was actually being read and deeply examined, instead of simply being forgotten on a shelf?
Regarding the Users' Guide hyperlinked at the left, it is "a comprehensive, user-oriented description of the APOLLO GN&C system ... revised as necessary to remain current", but not targeted at specific missions. However, given that it is dated July 1970, it is probably pretty accurate for Apollo 13.
Regarding the Programmed Guidance Equations document hyperlinked at the left, it is an MSC document whose purpose is "to provide more effective identification and analysis of various program performance features and to permit more effective review of published computer program documentation". In other words, while it does contain material related to guidance equations, it is perhaps better to think of this as being a pseudo-code description of the Luminary 116 program. (On the other hand, Section 5 of the GSOP, "Guidance Equations", also hyperlinked at the left, does indeed cover this topic explicitly.)
Scanned page images (big, medium quality!)
Scanned page images (very big, good quality!)
|Digital simulation of a lunar landing: low resolution
resolution||ZERLINA was an
off-the-main branch AGC program, by Don Eyles, which
experimentally developed a number of proposed improvements
to Luminary. Some of these improvements were actually
incorporated in later versions of Luminary ... but also,
many were never used, even where they were demonstrably
better, due to the need to avoid unnecessary risks —
changing software is always a risk! — as the Apollo program
approached its end. For example, I believe that improved
methods for increasing the positional accuracy of the
landing were explored in it, partially due to some ideas of
astronaut John Young, who flew Zerlina in the LM simulator.|
Our scan of ZERLINA, by the way, was financially sponsored by Linden Sims. Thanks, Linden!
Zerlina itself was apparently branched from Luminary 145, and was developed independently for a period of 6-7 months. Quite a few LUMINARY Memos describe the evolution of Zerlina, such as memos #138, #149, #161, #171, and #177. Memo #177 covers Zerlina 56 specifically, so as far as we know, 56 was probably the last version of Zerlina.
Zerlina was not the only such experimental branch of the AGC code, but it is the only one (that we know of) to have survived, and it is the one about which we have the most information.
Regarding the digital landing simulation linked at the left, it is an Apollo-era simulation run by Don Eyles, rather than a "modern" simulation done by the Virtual AGC project. The printout came from Don's own private hoard, and the scanning for our Internet Archive collection was financed by Niklas Beug and Alex Bart (thanks, guys!).
In fact, Nik has actually flown a lunar landing using Zerlina in the NASSP/Orbiter spacecraft simulator, and has shared a video of it:
14|| LM-8|| H-3|| Luminary 1D|| 178|| || Excerpted
LM Systems Handbook|
The solder ball
Users' Guide to Apollo GN&CS Major Modes and Routines, Rev 1
Apollo Guidance and Navigation Flowcharts, Program Luminary 1D (Rev 173): Volume 1/2 and Volume 2/2
Operational Data Book
| Regarding the Users' Guide hyperlinked
at the left, it is "a comprehensive, user-oriented
description of the APOLLO GN&C system ... revised as
necessary to remain current", but not targeted at specific
missions. However, given that it is dated July 1970,
it is probably pretty accurate for Apollo 14.|
Although we don't presently have the Apollo 14 LM software, Niklas Beug, a developer and user of NASSP, the Apollo-mission add-on for the Orbiter spaceflight simulator, tells us that it's actually possible to use a modified form of Luminary 210 (the Apollo 15-17 software) to fly satisfactory Apollo 14 missions. Let me simply quote Nik:
We currently don't have any AGC version available that was flown on Apollo 14, which causes a few, mostly procedural issues for NASSP. Apollo 14 was the only mission flown in the time period from July 1st, 1970 to July 1st 1971 and as such used a slightly different coordinate system than the AGC versions before and after that. And using a different coordinate system means that a few hardcoded constants had to be changed every year: star unit vectors, solar and lunar ephemeris in the LGC and a few other numbers. These numbers for the yearly coordinate system used by Apollo 14 are available or can be calculated. So we did just that and created our own AGC versions for Apollo 14. Both CMC and LGC are derived from the AGC versions flown on Apollo 15, Luminary 1E and Artemis (Colossus 3). We determined that these most closely match the programs and capabilities of the AGC versions actually flown on Apollo 14. One regular NASSP user (Alex Bart, ...) tested Apollo 14 with these modified AGC versions and flew the complete simulated mission with them. We are very confident now that these AGC versions are working as they should. As I said, they are essentially still the AGC versions flown on Apollo 15, only slightly modified to properly work with Apollo 14. ... They are available here, as Artemis072NBY71.bin and Luminary210NBY71.bin, [i.e.] Artemis072 and Luminary210 modified to work for the Nearest Besselian Year (NBY) coordinate system of 1971.
|N/A||N/A||J||Luminary 1D||209||AGC developer Allan Klumpp retained a copy
of Luminary 209, based on the the belief that it had flown
on Apollo 17. Unfortunately, this turns out not to
have been the case, and it was really Luminary 210 that flew
(see below). But that doesn't invalidate the value of
Luminary 209. We'd still like to scan it and present
it for you here!|
As it turns out, the printout was donated to klabs.org before we could get access to it, nor do we have access to it today, but perhaps we'll be able to scan it some day.
Apollo 15|| LM-10|| J-1||Luminary 1E||210|
As colorized, hyperlinked, HTML
Reduced-resolution high-contrast black&white PNG
Reduced-resolution scanned color JPG
High-resolution scanned JPEG 2000
| LGC Data
LM Familiarization Manual
|Luminary 210 is what flew on Apollo
15-17. The scan we have is taken from AGC developer
Don Eyle's collection, as scanned by archive.org, and
financially sponsored by our Jim Lawton. Thanks, Jim!|
Below, you can see a video made by Niklas Beug of a simulated Apollo 15 lunar landing, using this Luminary 210 AGC software and the Orbiter spaceflight simulator, with the NASSP 8.0 Apollo-mission add-on and our own AGC CPU simulator. (A higher-resolution version is probably available if you go directly to YouTube.)
Regarding "digital simulation" of the Apollo 17 landing hyperlinked at the left, it is an Apollo-era computer run (not one done by our project!), also from Don Eyles's collection, scanned by archive.org, and financially sponsored by our Fabrizio Bernardini. It includes things like the pad loads, position of the LM at any given time, what's displayed on the DSKY at those times, and so forth.
Regarding the Users' Guide hyperlinked at the left, it is "a comprehensive, user-oriented description of the APOLLO GN&C system ... revised as necessary to remain current", but not targeted at specific missions. However, given that it specifically references Colossus 3 and Luminary 1E, that seems pretty specific to Apollo 15, 16, and 17.
Apollo 16|| LM-11|| J-2|| Program Notes|
Operational Data Book
LM Familiarization Manual
| Apollo 17|| LM-12|| J-3||
Excerpted LM Systems Handbook|
Operational Data Book
LM Familiarization Manual
Landing digital simulation:
(The data in this table originally came from on-line sources, but in the form shown contains many corrections supplied by Paul Fjeld. Please don't take this information as authoritative!)
|Filename.agc||Source code for major subdivisions of the Luminary program.|
|MAIN.agc||Organizer which treats
all of the other assembly-language files (*.agc) as
include-files, to form the complete program.|
|Filename.binsource||Human-readable form of
the Luminary binary executable, as an octal listing.|
|Filename.bin||Binary executable created
from binsource (octal listing) file.|
Technically speaking....A point which may not be completely appreciated is that Luminary131.bin was not created from the assembly-language source files. Therefore, the byte-for-byte equivalence mentioned above actually has some significance. In fact, both the assembly-language source code and Luminary131.bin (or Luminary131.binsource) come from separate readings of the original Luminary assembly listing scan, so their equivalence provides an important check on validity. (See below.) The file Luminary131.bin was created from the human-readable/editable ASCII file Luminary131.binsource by means of the program Oct2Bin, with the following steps:
mv Oct2Bin.bin Luminary131.bin
Admittedly, few people are likely to perform any processing of this kind unless contributing a new version of the Luminary code to the Virtual AGC project.