Nasa's nearly 45-year-old Voyager-1 spacecraft is nothing short of a miracle.
Its current location is outside our solar system, but still, it is in contact with the Earth.
But it has presented its team with what NASA has classified as 'mysterious'.
It is working normally but sending some strange telemetry data to earth.
The problem may also be related to Voyager 1's Attitude Articulation and Control System, which manages its orientation in space, including the maintenance of its antenna on Earth.
"All indications suggest that AACS is still operating, but the telemetry data it is returning is invalid.
For example, the data may be randomly generated, or not reflect any possible conditions in which AACS could happen," NASA's Jet Propulsion Lab said in a statement issued Wednesday.
The data makes no sense, but Voyager 1 is maintaining a clear line of communication with the original location and the problem has not triggered a protective "Safe Mode".
The twin spacecraft Voyager 1 and Voyager 2 were launched in the 1970s and long ended their expected lifetimes.
They are both in interstellar space, which Voyager 1 and 2 project manager Suzanne Dodd describes as a "high radiation environment no spacecraft has flown before."
Voyager 1 is located at a distance of about 14.5 billion miles (23.3 billion kilometers) from Earth.
It takes a few days to send a signal and then listen back, which adds to the challenge of understanding what's going on.
This leaves NASA with a lot of unknowns. Is AACS the culprit or is another system experiencing the glitch? Will Voyager 1 be able to continue its science mission?
There are ways to move forward from this mess. Voyager 1 can just keep up with it. Or a software fix or a switch to backup hardware could be the solution.
NASA expects both Voyagers to continue sending back science data beyond 2025. "A mystery like this is par for the course at this stage of the Voyager mission," Dodd said.