Artist’s concept of the Voyager spacecraft in space. Credit: NASA

Something’s up with the data coming from Voyager 1. NASA says such an unexplained issue is not unexpected given the craft’s age and circumstances.

Launched in 1977, Voyager entered the interstellar plasma in 2015. That made it the first man-made object to leave our solar system and no longer be significantly affected by the sun.

The problem is with the attitude articulation and control system (AACS), which keeps its orientation steady. That’s necessary to point its antenna at Earth to transmit data.

As far as NASA engineers can tell, the AACS is still working (as shown by the fact they are still receiving signals at the expected strength). However, the telemetry data that shows what the AACS is doing is amiss: “For instance, the data may appear to be randomly generated, or does not reflect any possible state the AACS could be in.”

What’s likely good news is that Voyager 1 hasn’t gone into a safe mode that’s triggered by fault protection systems. It may take some time to figure out the problem and whether it will have long-term effects. One challenge is that with the craft 14.5 billion miles away, it takes almost two days to send a message to it and receive a reply.

NASA notes it’s hardly a surprise that such problems arise. Not only is the craft long past the lifespan for which it was built, but it’s now subject to extreme levels of radiation.