Voyager 1, The Most Distant Human-Made Object In Existence, Has Begun Beaming Back To Earth After Months Of Silence

After some innovative detective work, the mission team can, for the first time in five months, assess the health and status of the farthest human-made object ever created.

NASA's Voyager 1 spacecraft is now returning usable data about its onboard engineering systems, a milestone achieved for the first time since November. The next objective is to enable the spacecraft to resume sending back science data.

Voyager 1, along with its twin Voyager 2, are the only spacecraft to have ventured into interstellar space, the vast expanse between stars.

Voyager 1 ceased transmitting readable science and engineering data to Earth on 14 November 2023, although mission controllers could tell that the spacecraft was still receiving their commands and operating normally.

In March, the Voyager engineering team at NASA's Jet Propulsion Laboratory in Southern California identified the issue as being linked to one of the spacecraft's three onboard computers, specifically the flight data subsystem (FDS), which packages the science and engineering data before transmission.

After receiving data about Voyager 1's health and status for the first time in five months, members of the Voyager flight team celebrated in a conference room at NASA's Jet Propulsion Laboratory on 20 April.

The team found that a single chip responsible for storing a portion of the FDS memory, including some of the FDS computer's software code, was not functioning. The loss of that code rendered the science and engineering data unusable.

Unable to repair the chip, the team decided to relocate the affected code to other areas in the FDS memory. However, no single location was large enough to accommodate the entire section of code.

To address this, they devised a plan to divide the affected code into sections and store them in different locations within the FDS. To make this plan work, they also needed to adjust these code sections to ensure they still functioned as a whole. Any references to the location of that code in other parts of the FDS memory needed to be updated as well.

The team began by isolating the code responsible for packaging the spacecraft's engineering data and sent it to its new location in the FDS memory on 18 April.

Since a radio signal takes about twenty-two and a half hours to travel to Voyager 1, which is over 15 billion miles (24 billion kilometres) from Earth, and another twenty-two and a half hours for a signal to return to Earth, the team had to wait until 20 April to hear back from the spacecraft.

In the coming weeks, the team will relocate and adjust the other affected portions of the FDS software, including those responsible for returning science data.

Voyager 2 continues to operate normally. Launched over 46 years ago, the twin Voyager spacecraft are the longest-running and most distant spacecraft in history.

Prior to their interstellar missions, both probes explored Saturn and Jupiter, and Voyager 2 also visited Uranus and Neptune.