A new signal from humanity’s most distant spacecraft could be the key to restoring it.

On March 1, engineers sent a command up to Voyager 1—more than 15 billion miles (24 billion kilometers) away from Earth—to “gently prompt” one of the spacecraft’s computers to try different sequences in its software package.

But Voyager 1 responded to the March 1 troubleshooting command with something different from what engineers have seen since this issue first appeared on November 14.

“The new signal was still not in the format used by Voyager 1 when the FDS is working properly, so the team wasn’t initially sure what to make of it,” NASA said in an update Wednesday. “But an engineer with the agency’s Deep Space Network … was able to decode the new signal and found that it contains a readout of the entire FDS memory.”

Now, engineers are meticulously comparing each bit of code from the FDS memory readout to the memory readout Voyager 1 sent back to Earth before the issue arose in November. This, they hope, will allow them to find the root of the problem. But it will probably take weeks or months for the Voyager team to take the next step. They don’t want to cause more harm.

“Using that information to devise a potential solution and attempt to put it into action will take time,” NASA said.