Voyager 1 Sends Clear Data to NASA for the First Time in Five Months

The farthest spacecraft from Earth had been transmitting nonsense since November, but after an engineering tweak, it finally beamed back a report on its health and status

Voyager 1 team celebrating around a table
Members of the Voyager 1 flight team celebrate after receiving health and status data from the spacecraft. Next, engineers need to enable the probe to start sending science data again. NASA / JPL-Caltech

For the first time in five months, NASA has received usable data from Voyager 1, the farthest spacecraft from Earth.

The aging probe, which has traveled more than 15 billion miles into space, stopped transmitting science and engineering data on November 14. Instead, it sent NASA a nonsensical stream of repetitive binary code. For months, the agency’s engineers undertook a slow process of trial and error, giving the spacecraft various commands and waiting to see how it responded. Thanks to some creative thinking, the team identified a broken chip on the spacecraft and relocated some of the code that was stored there, according to the agency.

NASA is now receiving data about the health and status of Voyager 1’s engineering systems. The next step is to get the spacecraft to start sending science data again.

“Today was a great day for Voyager 1,” Linda Spilker, a Voyager project scientist at NASA’s Jet Propulsion Laboratory (JPL), said in a statement over the weekend, per CNN’s Ashley Strickland. “We’re back in communication with the spacecraft. And we look forward to getting science data back.”

Voyager 1 and its companion, Voyager 2, separately launched from Earth in 1977. Between the two of them, the probes have studied all four giant planets in the outer solar system—Jupiter, Saturn, Uranus and Neptune—along with 48 of their moons and the planets’ magnetic fields. The spacecraft observed Saturn’s rings in detail and discovered active volcanoes on Jupiter’s moon Io.

Originally designed for a five-year mission within our solar system, both probes are still operational and chugging along through space, far beyond Pluto’s orbit. In 2012, Voyager 1 became the first human-made object to reach interstellar space, the area between stars. The probe is now about eight times farther from the sun than Uranus is on average.

Over the decades, the Voyager spacecraft have transmitted data collected on their travels back to NASA scientists. But in November, Voyager 1 started sending gibberish.

Engineers determined Voyager 1’s issue was with one of three onboard computers, called the flight data system (FDS), NASA said in a December blog post. While the spacecraft was still receiving and executing commands from Earth, the FDS was not communicating properly with a subsystem called the telemetry modulation unit (TMU). The FDS collects science and engineering data and combines it into a package that the TMU transmits back to Earth.

Since Voyager 1 is so far away, testing solutions to its technical issues requires time—it takes 22.5 hours for commands to reach the probe and another 22.5 hours for Voyager 1’s response to come back.

On March 1, engineers sent a command that coaxed Voyager 1 into sending a readout of the FDS memory, NASA said in a March 13 blog post. From that readout, the team confirmed a small part—about 3 percent—of the system’s memory had been corrupted, NASA said in an April 4 update.

The core of the problem turned out to be a faulty chip hosting some software code and part of the FDS memory. NASA doesn’t know what caused the chip to stop working—it could be that a high-energy particle from space collided with it, or the chip might have just run out of steam after almost 50 years spent hurtling through the cosmos.

“It’s the most serious issue we’ve had since I’ve been the project manager, and it’s scary because you lose communication with the spacecraft,” Suzanne Dodd, Voyager project manager at JPL, told Scientific American’s Nadia Drake in March.

To receive usable data again, the engineers needed to move the affected code somewhere else that wasn’t broken. But no single location in the FDS memory was large enough to hold all of the code, so the engineers divided it into chunks and stored it in multiple places, per NASA.

The team started with moving the code responsible for sending Voyager’s status reports, sending it to its new location in the FDS memory on April 18. They received confirmation that the strategy worked on April 20, when the first data on the spacecraft’s health since November arrived on Earth.

In the next several weeks, the team will relocate the parts of the FDS software that can start returning science data.

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