Voyager 1 sends mysterious data from 14.5 billion miles away

"All signs suggest the AACS is still working, but the telemetry data it’s returning is invalid. For instance, the data may appear to be randomly generated, or does not reflect any possible state the AACS could be in," explains NASA. 

Engineers in charge of the probe report that the issue hasn't triggered the probe's fault protection systems, whose role is to put the spacecraft into “safe mode” should serious issues arise. 

In this mode, Voyager 1 would be able to conduct only essential operations, giving engineers time to diagnose an issue. Reassuringly, since Voyager 1's signal hasn't weakened, this must mean that its high-gain antenna remains in its prescribed orientation with Earth.

"The team will continue to monitor the signal closely as they continue to determine whether the invalid data is coming directly from the AACS or another system involved in producing and sending telemetry data. Until the nature of the issue is better understood, the team cannot anticipate whether this might affect how long the spacecraft can collect and transmit science data," said NASA.

Where is the Voyager 1 now?

Voyager 1 was first launched over 40 years ago, and is, officially, the furthest human-made object from Earth at a distance of over 14 billion miles away  (23.3 billion kilometers). At this distance, it would take light roughly 20 and a half hours to travel.

For transmissions to and from the probe, it takes about two days to both send and receive commands and data, which is a delay the missions team is all too well familiar with. 

“A mystery like this is sort of par for the course at this stage of the Voyager mission,” said Suzanne Dodd, project manager for Voyager 1 and 2 at NASA’s Jet Propulsion Laboratory in Southern California. “The spacecraft are both almost 45 years old, which is far beyond what the mission planners anticipated. We’re also in interstellar space – a high-radiation environment that no spacecraft have flown in before. So there are some big challenges for the engineering team. But I think if there’s a way to solve this issue with the AACS, our team will find it,” she added.

According to Dodd, we should probably prepare for the fact that it may not be possible to trace the apparent issue, and rather find a way to work around it. If it can be identified, however, corrections may be possible through a software update as actual hardware fixes are clearly out of the question. 

However, the craft does have some redundant hardware onboard that could also be utilized, if needed. This wouldn't be the first time this sort of fix has been attempted, either. 

Back in 2017, for example, Voyager 1’s primary thrusters showed signs of degradation. To fix the problem, NASA explains, engineers switched to another set of thrusters that had originally been used during the spacecraft’s planetary encounters.

Incredibly, despite not being used for over 37 years, they actually responded well. 

Thankfully, Voyager 2, Voyager 1's twin, doesn't appear to have any issues and is currently 12.1 billion miles, or 19.5 billion kilometers, from Earth.

"Launched in 1977, both Voyagers have operated far longer than mission planners expected, and are the only spacecraft to collect data in interstellar space. The information they provide from this region has helped drive a deeper understanding of the heliosphere, the diffuse barrier the Sun creates around the planets in our solar system," said NASA.

Both spacecraft operate on a paltry 4 watts of power a year, which obviously limits the kind of systems that can run continuously onboard. The mission engineering team has switched off various subsystems and heaters in order to reserve power for science instruments and critical systems.

As yet, now scientific instruments have been turned off,  and the Voyager team is working to keep the two spacecraft operating and returning unique science beyond 2025.

NASA assures us that its engineers will continue to work at solving the mystery that Voyager 1 has presented them. They also confirm that the mission’s scientists will continue to make the most of the data coming down from the spacecraft’s unique vantage point.