Two top examples of good (redundant but not only) design and coding:
https://www.nasa.gov/press-release/nasa-s-voyager-spacecraft-still-reaching-for-the-stars-after-40-years
Quoting:
"Because the Voyagers' power decreases by four watts per year, engineers are learning how to operate the spacecraft under ever-tighter power constraints. And to maximize the Voyagers' lifespans, they also have to consult documents written decade’s earlier describing commands and software, in addition to the expertise of former Voyager engineers.
"The technology is many generations old, and it takes someone with 1970s design experience to understand how the spacecraft operate and what updates can be made to permit them to continue operating today and into the future," said Suzanne Dodd, Voyager project manager based at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.
Team members estimate they will have to turn off the last science instrument by 2030. However, even after the spacecraft go silent, they’ll continue on their trajectories at their present speed of more than 30,000 mph (48,280 kilometers per hour), completing an orbit within the Milky Way every 225 million years.
The Voyager spacecraft were built by JPL, which continues to operate both. The Voyager missions are part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of SMD."
