The Voyager 1 Glitch: Rescuing a 1970s Probe From Billions of Miles Away

When humanity’s most distant spacecraft began transmitting repeating patterns of gibberish in late 2023, the situation looked grim. Voyager 1 is currently floating through interstellar space more than 15 billion miles from Earth. Against all odds, engineers at NASA’s Jet Propulsion Laboratory managed to diagnose a broken computer chip and beam a highly complex software patch across the solar system to bring the historic probe back to life.

The First Signs of Trouble

The crisis began in November 2023. Under normal circumstances, Voyager 1 gathers information about the interstellar environment and the health of its own systems. It packages this information into a usable format using its Flight Data Subsystem (FDS). The FDS then hands that packaged data over to the telemetry modulation unit, which beams the radio signals back to Earth.

Suddenly, that steady stream of science and engineering data stopped. Instead of transmitting readable binary code, Voyager 1 started sending back a repeating pattern of alternating 1s and 0s. It was the digital equivalent of a dial tone. The spacecraft was still alive and receiving commands, but the FDS was trapped in a loop.

Troubleshooting From 15 Billion Miles Away

Fixing a computer glitch is difficult enough on Earth, but doing it on a spacecraft launched in September 1977 requires immense patience. Because Voyager 1 is so incredibly far away, radio signals traveling at the speed of light take about 22.5 hours to reach the probe.

When engineers at the Jet Propulsion Laboratory (JPL) in Southern California sent a command, they had to wait an agonizing 45 hours to find out if the spacecraft responded.

In early March 2024, the team decided to send a “poke” command. This specific command prompted the FDS software to try different sequences in hopes of bypassing the corrupted section. The trick worked partially. On March 3, Voyager 1 sent back a signal that differed from the repeating 1s and 0s. A brilliant engineer on the Deep Space Network team decoded this new signal and realized it contained a complete readout of the FDS memory.

Finding the Hardware Culprit

By comparing this new memory dump to the last known good readout from before the glitch, the JPL team pinpointed the exact problem. About 3 percent of the FDS memory had become corrupted.

The engineers traced this 3 percent memory loss to a single failed hardware chip inside the spacecraft. This specific chip was responsible for storing a vital portion of the FDS memory code. Nobody knows exactly why the chip failed after 46 years. It might have been struck by a high-energy cosmic ray from deep space, or it may have simply worn out from nearly half a century of continuous operation.

Designing the Ingenious Software Patch

Because NASA could not physically replace a broken chip 15 billion miles away, they had to fix a hardware problem using a software solution. The team needed to move the essential code from the broken chip into a healthy section of the FDS memory.

This presented a massive coding puzzle. The remaining healthy memory on the ancient computer did not have a single open block large enough to hold the entire rescued section of code. To make it fit, the engineers had to slice the code into smaller chunks.

Here is how the team executed the fix:

  • Dividing the code: They separated the essential FDS software into smaller, distinct files.
  • Scattering the chunks: They stored these smaller chunks in various empty pockets spread across the healthy memory chips.
  • Adjusting the sequence: They rewrote portions of the code so that the divided chunks would still function together as one cohesive program.
  • Updating the pointers: They updated the digital reference points in other parts of the FDS software so the computer knew exactly where to look for the newly relocated code.

The Moment of Truth

On April 18, 2024, the JPL team beamed the first piece of the software patch toward the constellation Ophiuchus, where Voyager 1 currently resides. This initial transmission contained the code responsible for packaging the spacecraft’s engineering data.

After waiting 45 hours for the round trip, the team received a signal back on April 20. The patch was a total success. For the first time in five months, the engineers could see exactly how the spacecraft was functioning. Over the following weeks, the team beamed up the remaining chunks of code to fix the science data systems. By late May 2024, Voyager 1 was once again returning readable science data from its plasma wave subsystem and magnetometer.

The Future of Voyager 1

Voyager 1 and its twin, Voyager 2, are the only spacecraft to ever operate in interstellar space. They have completely crossed the heliosphere, which is the protective bubble of particles and magnetic fields generated by our Sun.

While the software patch saved the mission for now, the spacecraft faces an unavoidable expiration date. Voyager 1 is powered by radioisotope thermoelectric generators, which convert the heat from decaying plutonium into electricity. As the plutonium decays, the spacecraft loses about 4 watts of electrical power every year. To keep the probe alive, NASA has been slowly turning off non-essential systems and heaters. Even with these extreme conservation efforts, Voyager 1 will likely run out of power to operate its scientific instruments by the late 2020s or early 2030s.

Frequently Asked Questions

How far away is Voyager 1? As of 2024, Voyager 1 is over 15 billion miles away from Earth. It is moving away from the Sun at a speed of roughly 38,000 miles per hour.

When was Voyager 1 launched? NASA launched Voyager 1 on September 5, 1977. It actually launched a few weeks after its twin, Voyager 2, but it was put on a faster trajectory to reach Jupiter and Saturn.

What kind of computers does Voyager 1 use? Voyager 1 features three dual-redundant computer systems. These computers operate at a fraction of a megahertz and contain roughly 250,000 times less memory than a standard modern smartphone.

What is the Golden Record? Both Voyager probes carry a 12-inch gold-plated copper disk known as the Golden Record. It contains sounds of nature, musical selections from different cultures, spoken greetings in 55 languages, and 115 analog images intended to explain Earth to any extraterrestrial intelligence that might find the spacecraft millions of years from now.