Why did a NASA spacecraft suddenly start talking gibberish after more than 45 years of operation? What fixed it?

No, it’s not aliens, so don’t get too excited.

The general and golden rule with breaking bad news to someone is to tell them QUICKLY after indicating the need for conversation. But what do you do when you have to wait two days to get a basic response, and addressing that concern takes a couple of days as well?

For Linda Spilker and the team that oversees NASA’s Voyager 1 mission — an interstellar spacecraft 24 billion kilometres from us — it means five harrowing months of patience and problem solving.

To understand what we’re talking about, here’s a rough timeline of the voyages of Voyager 1.

Despite what the naming might suggest, Voyager 1 is actually the younger brother of the Voyager spacecraft twins. Launched in 1977, both Voyager 1 and Voyager 2 were created to study the four giant gas planets in our solar system. Having completed their fly-bys of these planets, Voyager 1 entered interstellar space in 2012, and is now currently swimming earnestly through the pitch black of in-between space as the most distant human-made object.

Considering how old and far away Voyager 1 is from us, it is a scientific marvel and a privilege that we still continue to receive sound scientific data from the spacecraft. To keep it functional after all these years, scientists have been periodically switching off a few systems and diverting the energy towards the satellite’s core functions. All seemed to be going well — until it didn’t.

According to NASA, Voyager 1 mysteriously stopped sending decipherable science and engineering data back to Earth on November 14. Fortunately, a myriad of independent controllers onboard were able to show that the spacecraft was still able to receive commands and was working normally, meaning the problem was localised. More importantly, it seemed fixable.

In March 2024, NASA engineers finally sussed out the issue: a single chip responsible for storing data captured by Voyager wasn’t working somehow. Age, hardware failure, or an unlucky spot of radiation exposure might have been the culprit, the team reckons.

As hinted earlier, it takes 22.5 hours to send a message to Voyager 1, and another 22.5 hours to get a confirmation back. Therefore, in the absence of a superhero spacefaring speedster to manually fix the spacecraft in person, scientists had to meticulously single out what code was lost due to the broken chip, and replace it.

However, the new problem was storage. The computers aboard the Voyagers were invented in the 70s, a time before the giga- and terabytes of sophisticated storage tech that we have today. Therefore, to fit all the missing code, the NASA engineers sliced it into smaller sections to be stored into whatever memory chips had space available onboard the Voyager 1.

“There were three different people looking through line by line of the patch of the code we were going to send up, looking for anything that they had missed,” Spilker explained to NBC. “And so it was sort of an eyes-only check of the software that we sent up.”

After much cross-checking, the team huddled into the office, waiting for a reply with bated breath. And lo and behold, came the lost-but-familiar beeping of Voyager’s operations clicking back into place. NASA reported this joyous news through a post on X, to which the spacecraft’s account replied with ‘Hi, it’s me. - V1’.

In the upcoming weeks, the team will be busy relocating and fine-tuning other segments of Voyager 1’s software, especially those primed to transmit scientific data. Meanwhile, Voyager 2 is still going strong after over 46 years since launch, making it the longest-running and most distant spacecraft in history. Its journey past Saturn, Jupiter, Uranus, and Neptune remains a remarkable feat in space exploration.