[TheCondor]

When was the first source code control system released? SCCS was like 1973 and the Voyager code was probably pretty much buttoned by then; with whatever practices that they thought was stable state of the art practices at the time. I imaging that this was a collection of "golden tapes" or something. Now the concept of revision control seems pretty self validating but you're talking about undergoing a culture change on your software team, pretty close to launch.

Then the voyager hardware was bespoke.

We just live in a different world now, they didn't know how to do software engineering like we do. They were just figuring it out. I really don't know the history of it but Voyager systems may have been produced on punchcard. Like the original source code might be physical for parts of the system.

[renhanxue]

The Voyager software was updated repeatedly and significantly in flight while the spacecraft were still in their early years. They were very intentionally designed to be patched over the course of the mission. The software as launched was not capable of a meaningful mission beyond Saturn, because for budget reasons that was officially not on the cards at launch (the Voyager name came very late; the program was officially "Mariner Jupiter-Saturn" for a long time). Features like image compression were added in the early 1980's, after Voyager 2's mission extension to Uranus and Neptune had been approved.

Without any inside information on the program, I would expect that a lot of development has been done more or less ad-hoc over the decades, as budgets have allowed and operational requirements demanded.

[zilti]

> they didn't know how to do software engineering like we do.

Yes, luckily. If they did, it would have broken after four years, and would have needed a second nuclear battery due to the inefficient code.