JPL scientists manipulate code on craft so incoming gibberish readable again.

NASA’s Voyager 1 is depicted in this artist’s concept traveling through interstellar space, or the space between stars, which it entered in 2012. In recent months, the spacecraft — launched Sept. 5, 1977 — had been sending unreadable data about its onboard engineering systems. NASA/JPL-CALTECH

By JOHN ORONA | SCNG

Rocket science? Brain surgery? A rescue mission?

Reconnecting with NASA’s Voyager 1 spacecraft was all of that for the Jet Propulsion Laboratory in La Cañada Flintridge, where months of concern and intense troubleshooting turned to smiles and relief this week.

That’s because the Voyager team at the sprawling Southern California lab on Saturday finally heard back from Voyager 1 again in a way that was more than just gibberish. It wasn’t ET calling home. But it was our own scientific masterpiece calling home in a way that actually made sense.

For the first time since November, Voyager 1 — the most distant human-made object from Earth at 15 billion miles — was once again returning usable data about the health and status of its onboard engineering systems.

It means scientists have more precious time to talk to the craft that is our farthest-reaching ambassador and discoverer in interstellar space. Instead of hurtling through space in a lost, lonely existence, it remains what it has always been: a pioneering scientific instrument offering data glimpses of a universe we can only imagine.

For most people it’s hard to imagine anything more difficult: How do you reestablish contact with something that is nearly 50 years old, starting to show its age, and 15 billion miles away.

But the team at JPL found a way. It wasn’t easy, though.After losing contact with the space probe in November, the team in March received the first signs of Voyager 1 being back online in five months. It took some clever computer engineering and an ongoing emergency operation from 15 million miles away.

“Today was a great day for Voyager 1,” Voyager project scientist Linda Spilker said in a statement to CNN over the weekend. “We’re back in communication with the spacecraft. And we look forward to getting science data back.”

The break in communication came due to a malfunction in one of the spacecraft’s three onboard computers, called the flight data subsystem, which is responsible for packaging the science and engineering data before it’s sent to Earth. With the data system unable to function, the space probe was receiving data and sending it back to NASA, but it was essentially unreadable gibberish.

Voyager 1 could hear the messages being sent from Earth but couldn’t respond coherently, providing no information on its health or status.

However, the fact that the ever-dependable Voyager, now years past its expected useful life, was still operating gave the team enough hope to attempt what would essentially be brain surgery on the space probe to get it communicating properly again.

Unable to simply repair the part, the team decided to place code elsewhere in the flight data subsystem memory, but since it was too large to put in any single location, it had to break it up in sections, which required it to adjust the code to ensure it all worked together functionally and update the system.

The team started by singling out the code responsible for packaging the spacecraft’s engineering data, which it completed April 18.

It took nearly a day for NASA’s radio signals to reach the probe and another day to hear back while scientists listened intently for a message from deep space, but finally they heard a familiar response.

In the coming weeks, the team will relocate and adjust the other affected portions of the flight data subsystem software and begin to once again receive scientific data from Voyager 1.

“We never know for sure what’s going to happen with the Voyagers, but it constantly amazes me when they just keep going,” Voyager Project Manager Suzanne Dodd said in a statement. “We’ve had many anomalies, and they are getting harder. But we’ve been fortunate so far to recover from them. And the mission keeps going. And younger engineers are coming onto the Voyager team and contributing their knowledge to keep the mission going.”

In case you’re wondering, remember Voyager 1 has family: Voyager 2.

Voyager 2 continues to operate normally, though last year JPL engineers used a long-shot maneuver to get it to begin returning data again, too.

Launched more than 46 years ago, the twin Voyager spacecraft are the longest-running and most distant spacecraft in history — or at least our history.

They’ve racked up quite a résumé.

Before they ever got to interstellar space, where they are now (a first in its own right), both probes flew by Saturn and Jupiter, and Voyager 2 flew by Uranus and Neptune.

Voyager 1 discovered a thin ring around Jupiter and two new Jovian moons: Thebe and Metis. At Saturn, the craft found five new moons and a new ring called the G-ring.

By February 1998, it had become the most distant human-made object after overtaking NASA’s Pioneer 10. And by 2012, it entered a whole new ballgame: interstellar space.

Interestingly, according to JPL, Voyager 1 was launched after Voyager 2, but because of a faster route, it exited the asteroid belt earlier than its twin, having overtaken Voyager 2 on Dec. 15, 1977.

Who knows. There’s always the chance — however remote — that it comes across some folks from another world. If it does, they’ll find messages in the Voyagers from Earth, prepared by a group headed by the late scientist Carl Sagan.

There’s a gold-plated copper disc with inscribed symbols to show the location of Earth relative to several pulsars. Audio on the disc includes greetings in 55 languages and 35 sounds from life on Earth: whales singing, human laughter, some Mozart and Bach, and some Chuck Berry.

Bottom line: We’re reunited for now, and it feels so good.