"Yes, move 0xFF to the register at position IX+0xBEEF"
Testing that hypothesis was a job for software developers, as Jet Propulsion Laboratory chief engineer Chris Jones said “The Voyager flight team dug up decades-old data and examined the software that was coded in an outdated assembler language, to make sure we could safely test the thrusters."
Shurely assembler languages never become "outdated". They are just mnemonics for machine instructions and don't need to carry around the whole "ecosystem" of compilers, optimizers, frameworks, deployment infrastructure and consultants.
Well, ok, now we have typed assembly language, and about time too. But still.