Mysterious problems have been going on with NASA's Voyager 1 spacecraft since 1977

Voyager 1 continues to do well, despite its advanced age and 14.5 billion miles (23.3 billion km) from Earth. It can receive and execute commands sent from NASA, as well as collect scientific data and transmit it back.

But readings from the Expression and Attitude Control System, which controls the orientation of the spacecraft in space, don’t match what Voyager actually does. The Expression and Attitude Control System, or AACS, ensures that the probe’s antenna remains pointed toward Earth so Voyager can send data back to NASA.

Due to Voyager’s interstellar position, light takes 20 hours 33 minutes to travel in one direction, so it takes two days to communicate and respond to a single message between NASA and Voyager.

So far, the Voyager team believes AACS is still functioning, but readings of instrument data appear random or impossible. System issues haven’t caused anything to put the spacecraft into “safe mode”. It was then that only basic operations took place so that engineers could diagnose problems that would endanger the spacecraft.

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And Voyager’s signal is still as strong as ever, meaning the antenna is still pointing toward Earth. The team is trying to determine if this erroneous data comes directly from this tool or if another system is causing it.

According to a NASA release, “Until the nature of the problem is better understood, the team cannot predict whether this could affect how long it takes the spacecraft to collect and transmit scientific data.”

“Puzzles like these are somewhat similar to the paths of the current Voyager mission,” Susan Dodd, project manager for Voyager 1 and 2 at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement.

“The spacecraft is about 45 years old, which is way beyond what mission planners expected. We are also in interstellar space – a highly radioactive environment where no spacecraft has ever 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.”

What Voyager 2 has learned since entering interstellar space

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If the team doesn’t identify the source of the problem, Dodd says, they may adapt. Or if they can find it, the problem can be solved by making software changes or relying on redundant hardware systems.

Voyager has relied on a backup system to survive. In 2017, the probe launched the thrusters that were used during the early planetary encounters during the 1970s – and are still operational after 37 years of disuse.

Older probes produce very little energy per year, so subsystems and heaters have been turned off for years so scientific platforms and instruments can continue to function.

The Voyager 2 spacecraft, the twin spacecraft, continues to do well in interstellar space 12.1 billion miles (19.5 billion km) from Earth. By comparison, Neptune, the farthest planet from Earth, is only 2.9 billion miles away. Both probes were launched in 1977 and far exceeded their original purpose of flying over the planet.

Now, they are the only two spacecraft to collect data from interstellar space and provide insight into the heliosphere, or the bubble created by the sun that extends beyond the planets in our solar system.

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