The 45-year-old Voyager 1 space probe, which explores space outside the solar system, encountered a strange problem at the beginning of the year. It started to transmit wrong data telemetry – while its other systems worked normally. Scientists have now managed to solve the problem, but its root cause is still unknown.

The failure concerned the probe’s articulation and position control system (AACS), which holds Voyager’s antenna in the direction of Earth. Then the spacecraft began sending incorrect data to controllers about its condition and activity.

As it turned out, at a certain moment the system started to forward data through the on-board computer, which has not been working for many years. This distorted the transmission of information. When the scientists suspected what the problem was, they resumed sending the data through another computer. It worked.

Engineers are now trying to determine why the system started transmitting data through the wrong computer. It probably received a wrong command from another on-board computer. The problem does not pose a long-term threat to the spacecraft, but the team will look for the source of the malfunction.

“We’re happy to have the telemetry back. 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 scientists say.