Voyager 1 experienced a communications glitch with its flight data system, complicating the transmission of data to Earth and creating challenges for engineers due to the spacecraft's age and distance. Engineers are working to resolve a problem with one of Voyager 1's three onboard computers, known as the Flight Data System (FDS).

In this artist's concept, NASA's Voyager 1 spacecraft travels through interstellar space, the space between stars, where it entered in 2012. Its twin brother Voyager 2 traveled on a different trajectory and entered interstellar space in 2018. Image source: NASA/JPL-Caltech

The spacecraft was receiving and executing commands from Earth; however, the flight data system was unable to communicate properly with one of the probe's subsystems, the Telecommunications Unit (TMU). Therefore, no scientific or engineering data is transmitted back to Earth.

FDS is designed to collect data from scientific instruments as well as engineering data about the health and status of the spacecraft. It then combines this information into a data "packet" that is sent back to Earth by the TMU. Data exists in the form of ones and zeros (or binary code). Different combinations of these two numbers are the basis of all computer languages.

Recently, the TMU started transmitting a repetitive pattern of 1's and 0's and seemed to be "stuck". After ruling out other possibilities, the Voyager team determined that the source of the problem was FDS. Over the weekend, the research team tried to restart the FDS to restore it to the state it was in before the problem occurred, but the spacecraft still did not return usable data.

It could take several weeks for engineers to come up with new plans to fix the problem. Launched in 1977, Voyager 2 and its twin Voyager 2 are the two longest-running spacecraft in history. Finding solutions to problems encountered by detectors often requires consulting original documents written decades ago by engineers who did not anticipate problems like these today. Therefore, the team needs time to understand how the new instructions will affect the operation of the spacecraft to avoid unintended consequences.

Additionally, instructions from mission controllers on Earth take 22.5 hours to reach Voyager 1, which is exploring the outer reaches of the solar system more than 15 billion miles (24 billion kilometers) from Earth. This meant the engineering team had to wait 45 hours to get a response from Voyager 1 and determine whether the command had the desired effect.