For months, NASA's Voyager team has been struggling to translate garbled messages from beyond our solar system. Voyager 1 has been responding to NASA's data requests with tangles of 1s and 0s, none of which have made sense to anyone at the agency. But now, thanks to a "poke command" issued in March, the spacecraft seems to have helped scientists identify the error behind its wonky transmissions.
NASA had just managed to solve an issue with Voyager 1's attitude articulation and control system (AACS) in 2022 when a new glitch arose, jumbling the probe's flight data. This raw data is supposed to convey information about what Voyager 1's various scientific instruments have gleaned from remote regions of the Milky Way, but instead, it was just a mysterious stream of unintelligible numbers. Getting the spacecraft to return to its original "language" has been a challenge ever since, in part because most of the folks who originally worked on Voyager 1 are no longer alive.
In March, NASA sent Voyager 1 a poke command, or a command that directly modifies a system's memory addresses. Though poke commands are a fairly antiquated concept, they're occasionally useful for low-level memory control—a stone the Voyager team couldn't leave unturned. Their command prompted Voyager 1's system into using a different readout sequence for its software package than it typically defaults to, and about 22 hours later, NASA found itself with a new clue.
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According to a Voyager mission blog post, activity from one portion of Voyager 1's flight data system (FDS) stood out from the probe's previous unreadable transmissions. A single engineer involved in NASA's Deep Space Network saw that the data contained a readout of Voyager 1's full FDS memory. This, the engineer noticed, offered the team an opportunity to compare and contrast Voyager 1's previous FDS readout with the latest snapshot of its inner workings.
NASA has since used the decoded readout to determine that roughly 3 percent of the probe's memory is corrupted. This may explain why restarting the FDS didn't resolve the issue back in November: If a system's memory has degraded, turning that system off and back on again won't do anything to bring it back. Luckily, engineers at the Voyager mission think the corruption is confined to just one chip, which could make the issue easier to circumvent or resolve.
