A NASA engineering team is investigating a mystery that occurred on the Voyager 1 spacecraft.

Voyager 1 is the most remote man-made object in existence, having been launched 44 years ago. It is currently operating at the edge of the solar system, flying through an “interstellar medium” far from the influence of the Sun.

However, the scientists found that the craft receives and successfully executes commands from Earth – but the readings from the probe’s Attitude Expression and Control System (AACS) do not reflect what is actually happening aboard Voyager 1.

The system maintains the craft’s orientation, keeping its antenna pointed precisely at Earth so that data from it can be sent to NASA. While all indications are that the AACS system is operating as normal, the telemetry data it returns appears to be randomly generated – and does not reflect any possible state the system could be in.

Furthermore, the problem hasn’t caused any failure protection system to put the Voyager into safe mode, nor has the signal weakened — indicating that the antenna is still in its normal position, pointing toward the ground.

NASA says it will continue to monitor the situation, as it is possible that invalid data is being generated by another system, but says it does not understand why this is happening or how long this problem could persist. It takes approximately two days for a message from Earth to reach Voyager and get a response from the craft.

“A puzzle like this is a bit like the course at this point in the Voyager mission,” said Susan Dodd, Voyager 1 and 2 project manager at NASA’s Jet Propulsion Laboratory in Southern California.

“The spacecraft is about 45 years old, which is far beyond what mission planners expected. We are also in interstellar space – a highly radioactive environment where no spacecraft has flown before. So there are some big challenges for the engineering team. But I think That if there is a way to solve this problem with AACS, our team will find it.”

There’s a chance that NASA won’t find the source of the problem and instead have to make software changes or use one of the craft’s backup systems — something it did before in 2017 when Voyager had to switch from its primary thrusters to secondary ones. due to signs of deterioration.