# What programs did David Scott add to the Apollo computer for Apollo 15?

David Scott was the commander for Apollo 15. He was also a main point of contact between MIT, who developed the Apollo flight computer, and the astronauts who were going to use that computer. Apparently, he liked the computer a lot:

[...] he developed great affection for the Apollo computer, and also the ability to add his own programs to it, which he did as commander of Apollo 15.

from: Charles Fishman, "One Giant Leap", p. 134

What programs did Scott add to the Apollo 15 and where these unique to that mission?

• Potential useful links?: Luminary Improvements and David's Scott's view on the AGC. Both links from here. Apr 12, 2020 at 17:43
• @StarMan Thanks. Some interesting pointers, but haven't found a conclusive answer in there yet.
– Ludo
Apr 14, 2020 at 14:49

TL;DR He didn't

I purchased One Giant Leap to research your question; a complete quote from the section you reference is here:

Dave Scott was one of the main points of contact between the astronauts and MIT, and he developed great affection for the Apollo computer, and also the ability to add his own programs to it, which he did as commander of Apollo 15. "How do you take a pilot, put him in a spaceship, and have him talk to a computer? That's not easy, in real time," Scott said. "[The onboard computer] was, with its computational ability, a joy to operate. It was just a tremendous machine. It was so simple and straightforward that even pilots could learn how to use it."$$^\text{70}$$

Reference 70 is:

Scott, "Speech at the Opening of the Computer Museum."

Not very helpful, as far as I can find, he did not speak at the opening of the Computer History Museum in Mountain View, California.

However, searching the excerpts of his speech leads me to an older book (published 23 years before), "Journey to the Moon (Library of Flight)" by Eldon C Hall with a larger excerpt,

We also had this panel that was operated by the crew, and great debates occurred relative to what it should look like. How do you talk to a computer? How do you take a pilot, put him in a spaceship and have him talk to a computer? That is not easy in real-time. Somebody at MIT came up with the verbnoun concept, but I'm surprised that it is not utilized in other computers today. It was very simple for us to operate with a series of two-digit numbers representing verbs and another series of two-digit numbers representing nouns. It was so simple and straightforward that even pilots could learn how to use it. $$^\text{5}$$

Digging into that reference gives us:

Astronaut David Scott, Commander of Apollo 15. From the transcript of Scott's address "The User's Point of View," presented at the Boston Computer Museum's inaugural, 1982.

I tracked this down with the assistance of Massimo Petrozzi from the Computer History Museum. The original talk is on Youtube here. I got it transcribed, and you can see the transcription here. The transcription posted by Star Man is close. It definitely comes from the same event, and it looks like it was just cleaned up for distribution.

Scott talks about his experiences with the Apollo Guidance Computer and talks programs and extensions to the computer, but he never mentions adding them himself. He did, however, talk about the extensive testing and review the software went through and that it needed to get a lockdown and committed to physical rope memory weeks before launch.

The cited reference does not support the claim made by the text.

Scott was the astronaut representative to MIT, who wrote the AGC software. There is even a memo written by him after his moon landing, with several very specific improvements to the LUMINARY (Lunar Lander) software, referred to as "famous" in another memo. However, as far as I can find, he did not write code and did not program the AGC. However, he did work closely with the team that did.

• I attempted to find some contact information for Charles Fishman, Simon & Schuster, an editor, or fact-checker for this book but was unable to find any. If anyone knows of a way to get in contact please let me know! May 3, 2021 at 23:35
• Sounds like Fishman conflated operating the computer with programming it. May 3, 2021 at 23:41
• That would make sense May 3, 2021 at 23:44
• This quote from his memo "A program or routine which whould permit manual updating of the LGC with range (Tapemeter R/ft, CSM VHF) and/or angle (FDAI, DEDA) y data." sounds like he wanted them to add a program. But, agreed, not do it himself. May 4, 2021 at 0:24
• Excellent research! Another interesting quote from that talk, on his Apollo 9 flight: "[...] I figured out a little program in the command module, with the help from my MIT buddies, to monitor their burn in reverse direction." Apparently the computer allowed some way of defining custom routines, but I'm going to guess it is more of a parameterization of existing programs, not programming in the sense of "coding".
– Ludo
May 4, 2021 at 10:19