Flight Software Workshop
2 HN recommenders · recommended in 3 months, 2026
1:03:45 · 17K views · Apr 16, 2025
JPL's David Cummings presents at the 2025 Flight Software Workshop how the team diagnosed and fixed the 2023 Voyager 1 anomaly from billions of miles away. It walks through the flight computer and the memory fix.
Commenters recommend it for the remarkable remote reverse engineering done on decades-old hardware with no simulator.
3 comments from Hacker News
A slight tangent here is a technical deep dive on Voyager 1 fixing a memory corruption error in 2023 by hand 15 billion miles away. Blows my mind of the reverse engineering done to achieve this this video
Here's a talk about how the Voyager team fixed the flight data computer on Voyager 1 when a memory chip went bad on it a few years ago. It goes over how the flight computer works and he walks through a few assembly routines. this video Some of the challenges they had to deal with while developing the fix: - The only source code they had for the flight data software was an OCR'd Microsoft Word document (with typos) that was likely scanned from a hard copy assembler listing printout. - The processor runs a custom instruction set developed by JPL for the Voyager mission. The documentation they had on the processor was incomplete. - Everybody who had designed the flight software was dead. - They had no assembler, no debugger, and no processor simulator. They had no testbed, the only two FDS processors were in space.
Based on the communication fix, they also didn't have a simulator, or tests, or complete source code, on a custom instruction set that wasn't well documented, so they had to reverse engineer how it worked. this video