Two months before the Voyager probes were shipped for launch it was found out that Jupiter's magnetic fields and radiation environment were a lot stronger than

Two months before the Voyager probes were shipped for launch it was found out that Jupiter's magnetic fields and radiation environment were a lot stronger than anticipated, in excess of what the spacecraft were designed to tolerate. They ended up wrapping many of the cables on the spacecraft with aluminum foil bought from a local supermarket as a protective measure.