Voyager 1 regains communication with NASA after an inventive solution

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For the first time in five months, NASA engineers have received decipherable data from Voyager 1 after coming up with a creative solution to solve a communications problem aboard humanity’s farthest spacecraft in the cosmos.

Voyager 1 is currently about 15 billion miles away, and at 46 years old, the probe has shown several oddities and signs of aging in recent years.

The latest problem faced by Voyager 1 first occurred in November 2023, when the flight data system’s telemetry modulation unit began sending an indecipherable repetitive code pattern.

Voyager 1’s flight data system collects information from the spacecraft’s scientific instruments and bundles it with technical data that reflects its current health status. Mission control on Earth receives that data in binary code, or a series of ones and zeros.

But since November, Voyager 1’s flight data system has been stuck in a loop. Although the probe has continued to provide a stable radio signal to the mission control team on Earth in recent months, the signal contained no useful data.

The mission team received the first coherent data on the health and status of Voyager 1’s technical systems on April 20. While the team is still assessing the information, everything they have seen so far indicates that Voyager 1 is healthy and functioning properly.

“Today was a great day for Voyager 1,” Linda Spilker, Voyager project scientist at JPL, said in a statement Saturday. ‘We have regained contact with the spacecraft. And we look forward to getting scientific data back.”

The breakthrough came as a result of a clever bit of trial and error and unraveling a mystery that led the team to a single chip.

After the problem was discovered, the mission team attempted to send commands to restart the spacecraft’s computer system and learn more about the underlying cause of the problem.

The team sent a command called a “poke” to Voyager 1 on March 1 to cause the flight data system to run several software sequences in hopes of figuring out what was causing the glitch.

On March 3, the team noticed that activity from part of the flight data system stood out from the rest of the garbled data. Although the signal was not the size the Voyager team is used to seeing when the flight data system functioned as expected, an engineer from NASA’s Deep Space Network was able to decode it.

The Deep Space Network is a system of radio antennas on Earth that help the agency communicate with the Voyager probes and other spacecraft exploring our solar system.

The decoded signal included a readout of the entire flight data system’s memory.

By examining the readout, the team determined the source of the problem: 3% of the flight data system’s memory was damaged. A single chip responsible for storing a portion of the system memory, including some of the computer’s software code, malfunctions. Although the cause of the chip’s failure is unknown, it could have worn out or been hit by an energetic particle from space, the team said.

The loss of the code on the chip rendered Voyager 1’s scientific and technical data unusable.

With no way to repair the chip, the team opted to store the chip’s affected code elsewhere in the system memory. Although they couldn’t pinpoint a location large enough to contain all the code, they were able to divide the code into sections and store it in different places in the flight data. system.

“To make this plan work, they also had to adjust those code sections to ensure, for example, that they all still function as one,” an update from NASA said. “Any references to the location of that code in other parts of the (flight data system) memory also had to be updated.”

After determining the code needed to package Voyager 1’s technical data, engineers sent a radio signal to the probe on April 18 that sent the code to a new location in the system’s memory.

Given Voyager 1’s enormous distance from Earth, it takes about 22.5 hours for a radio signal to reach the probe, and another 22.5 hours for a response signal from the spacecraft to reach Earth.

On April 20, the team received the response from Voyager 1, indicating that the smart code change had worked and that they could finally receive readable technical data from the probe again.

In the coming weeks, the team will continue to move other affected parts of the system software, including those responsible for returning the valuable scientific data that Voyager 1 collects.

Originally designed to last five years, Voyager 1 and its twin, Voyager 2, were launched in 1977 and are the longest operating spacecraft in history. Their exceptionally long lifetimes mean that both spacecraft have provided additional insights about our solar system and beyond after achieving their tentative goals of flying past Jupiter, Saturn, Uranus and Neptune decades ago.

The probes are currently venturing into uncharted cosmic territory along the outer reaches of the solar system. Both are in interstellar space and are the only spacecraft to ever operate outside the heliosphere, the solar bubble of magnetic fields and particles that extends far beyond Pluto’s orbit.

Voyager 2, operating normally, has traveled more than 20.3 billion kilometers from our planet.

Over time, both spacecraft have encountered unexpected problems and outages, including a seven-month period in 2020 when Voyager 2 was unable to communicate with Earth. In August 2023, the mission team used a remote “shout” technique to restore communications with Voyager 2 after a command accidentally pointed the spacecraft’s antenna in the wrong direction.

The team estimates that it will be a few weeks before scientific data is received from Voyager 1 and is looking forward to seeing what that data contains.

“We never know for sure what will happen to the Voyagers, but I am continually amazed when they continue as normal,” Voyager project manager Suzanne Dodd said in a statement. “We’ve had a lot of deviations, and they’re becoming more and more difficult. But we have been lucky to recover from it so far. And the mission continues. And younger engineers are joining the Voyager team and contributing their knowledge to keep the mission going.”