As it turns out, spacecraft aren’t immune to age. In November 2023, NASA’s over 46-year-old Voyager 1 spacecraft started sending a stream of nonsense to Earth, spewing out signals without any morsel of meaning. The nonsense continued for more than five months, with members of the Voyager 1 mission team rushing to resolve the issue.
In April 2024, NASA announced that the aging spacecraft is finally returning meaningful messages. But despite this recent resolution, the breakdown in communication itself is still a concern, casting doubts on the durability of the probe and about why its systems are so prone to problems — a product, it seems, of the passage of time.
Read More: The Best of Voyager: The Longest-Running Space Mission in History
What Went Wrong with Voyager 1?
Sent into space in 1977 as part of NASA’s Voyager mission, the Voyager 1 spacecraft has traveled more than 15 billion miles through space. Throughout its travels, the spacecraft has collected information about its status and its status while drifting deeper and deeper into the universe, compiling insights on the outer solar system and the space beyond the outer solar system alongside its twin, the Voyager 2 spacecraft.
The probe has had its fair share of bugs throughout the course of its trip, with one of its biggest blips beginning in November. Though the spacecraft continued to receive and respect the commands of the Voyager 1 mission team, its communication system started to fail at around that time, meaning the spacecraft stopped sending meaningful signals of its own. Instead, it was stuck returning a repeating sequence of ones and zeros, rather than its typical output of important insights condensed in convenient bundles of binary code.
As of now, the spacecraft’s sense seems mostly restored. Voyager 1 is returning sensible systems information once again, and is anticipated to return sensible science information soon. But this isn’t the only problem that’s troubled the probe, interrupting its interstellar investigations. In fact, after almost fifty years of flight, Voyager 1 is increasingly showing signs of its age.
Read More: Voyager: The Man Behind the Mission
Why Is Voyager 1 Prone to Problems?
Initially intended to study Jupiter and Saturn, Voyager 1 and Voyager 2 were built to survive only five years of flight. But as their flybys of the two planets came to a close and as their trajectories forged further and further into space, it seemed a shame to cut their travels short. In time, their two-planet mission transformed into a four-planet mission, and their four-planet mission transformed into an interstellar mission, as the probes became the first spacecraft to shoot into the space between stars, in 2012 and 2018 respectively.
Since then, though, Voyager 1’s smooth sailing has become bumpier and bumpier, possibly a product of age. In 2017, for instance, the probe’s primary thrusters started to struggle, pushing the Voyager 1 team to switch to its secondary thrusters to maintain its ability to align itself for communication. And in 2022, Voyager 1’s attitude articulation and control system (AACS) met with a malfunction of its own, reducing the spacecraft’s messages to meaningless nonsense, a lot like the issue that started in November.
Aside from these issues, it’s the diminishing power supplies of the aging spacecraft that pose the biggest problems: As the Voyagers’ power diminishes, scientists are slowly switching off some of their scientific instruments in an attempt to save others. It’s a strategic move, as mission team members attempt to get as much information out of the probes as possible, though issues, including Voyager 1’s November glitch, only get in the way of that goal.
Read More: Voyager: What’s Next for NASA’s Interstellar Probes?
What Fixed Voyager 1?
Identifying the issue in the spacecraft’s computers, the Voyager 1 mission team concluded that the November conundrum arose from a “corrupted section” in the memory of one of Voyager 1’s communication systems, called the flight data subsystem (FDS). This subsystem bundles the information collected by the probe before it is beamed back to the mission team.
In December, the mission team restarted the FDS, though the restart failed to return the subsystem to its functional state. In the aftermath of the attempt, the team then decided to send a command called a “poke” to the probe on March 1. The poke was cautiously considered and planned to push the corrupted subsystem to work around its corruption.
A response was received on March 3, not nonsense, but still difficult to discern. The delay in the response was anticipated — it takes 22.5 hours for signals to reach the probe and another 22.5 hours for signals to reach the mission team — but the response was cryptic. It wasn’t until March 10 that the mission team members determined the response carried a readout of the FDS memory, including its initial instructions and any altered code, whether altered by command or by the status of the spacecraft.
By comparing the readout to those received before the issue began, the team confirmed that around 3 percent of the FDS memory was corrupted, obstructing the computer’s operations. The affected code, the team then concluded and announced on April 4, 2024, was probably contained on a single computer chip.
Opting to work around the inoperative computer chip, the team decided to divide the affected code into smaller sections (some connected to the sending of systems data and some connected to the sending of science data) and to insert those smaller sections into other, operative places in the FDS memory.
The team sent out the orders to move some of the spacecraft’s affected code on April 18 and received a response with intelligible systems information on April 20. Soon, the team will send out the orders to move more of the spacecraft’s affected code, with the intention that they will receive a response with intelligible science information, as well.
Though apparently averted, this Voyager 1 communication crisis still points to the precarity of the spacecraft and to the time that’s required to resolve its issues — a particularly precious resource for the constantly aging probe.
Read More: 5 NASA Spacecraft That Are Leaving Our Solar System for Good
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Our writers at Discovermagazine.com use peer-reviewed studies and high quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
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Sam is a journalist covering archaeology, paleontology, ecology and evolution for Discover, along with an assortment of other topics. Before joining the Discover team as an assistant editor in 2022, Sam studied journalism at Northwestern University in Evanston, Illinois.
