AACS, the probe's attitude articulation and control system, failed to accurately represent what was happening aboard back in May 2022. Now, the mystery has been solved.
A data issue with NASA’s Voyager 1 spacecraft has been resolved by engineers. Voyager 1’s attitude articulation and control system (AACS), which maintains the probe’s antenna pointed at Earth, began sending garbled information about the probe’s health and activity earlier this year, despite normal performance.
AACS, the probe’s attitude articulation and control system, failed to accurately represent what was happening aboard, as we reported back in May 2022. Spacecraft orientation is handled by the AACS. Voyager 1’s high-gain antenna ensures that it is pointed accurately at our planet for communication with Earth.
The AACS did not appear to be malfunctioning in May, but its telemetry data was invalid. In some cases, the data was generated in a random manner or did not reflect the state of AACS at all.
As the probe continued to collect and return data, it appeared to be in good health.
Since then, the team has found the source of the garbled data: the AACS sent the telemetry data through an onboard computer known to have stopped working years ago, which corrupted the data.
According to Suzanne Dodd, Voyager’s project manager, they decided to use a low-risk solution: commanding the AACS to send data to the correct system again.
The AACS may have received a faulty command from another onboard computer that caused it to route telemetry data to the wrong computer. Engineers don’t know exactly why the AACS began routing telemetry data to the wrong computer. If this is the case, it indicates an issue elsewhere on the spacecraft. Voyager 1’s long-term health isn’t threatened by that underlying issue, but the team will continue to look for it.
Having telemetry back is a relief for us,” said 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.”
The twin Voyager 1 and 2 spacecraft are exploring areas never before explored by a spacecraft from Earth. Their journey has taken them more than 40 years since their 1977 launches, and they now each reside much farther away from Earth and the sun than Pluto.
Voyager 1 entered interstellar space in August 2012, a region filled with material ejected by nearby stars that died millions of years ago.
It was announced on November 5, 2018, that Voyager 2 had entered interstellar space, and scientists hope to learn more about this region. Through the Deep Space Network or DSN, both spacecraft continue to exchange scientific information about their surroundings.