For most of the year, NASA's Voyager 1 spacecraft has been sending home mysterious system data. Launched in 1977, the Voyager 1—and its Golden Record, the iconic message for extraterrestrials—is currently 14.5 billon miles from Earth in interstellar space. So far, the Voyager mission has lasted far longer than ever expected, but in May, engineers determined that Voyager 1 was transmitting weird data about the health and activities of its attitude articulation and control system (AACS) responsible for aiming the probe's antenna pointed in the right direction.
Now, researchers determined that the onboard computer the AACS was transmitting the telemetry data through was corrupting the signals. They fixed the issue by reprogramming the AACS to send the data through a different computer. That solved the problem but revealed another mystery: the computer that corrupted the data hasn't worked at all in years and they have no idea why Voyager suddenly started using it again.
From NASA's Jet Propulsion Laboratory:
Engineers don't yet know why the AACS started routing telemetry data to the incorrect computer, but it likely received a faulty command generated by another onboard computer. If that's the case, it would indicate there is an issue somewhere else on the spacecraft. The team will continue to search for that underlying issue, but they don't think it is a threat to the long-term health of Voyager 1.
"We're happy to have the telemetry back," said [Voyager program manager Suzanne] Dodd. "We'll do a full memory readout of the AACS and look at everything it's been doing. That will help us try to diagnose the problem that caused the telemetry issue in the first place. So we're cautiously optimistic, but we still have more investigating to do."