NASA Is One Step Closer to Fixing Voyager 1

NASA's Voyager 1 deep space probe has spent 46 years exploring the furthest reaches of our solar system and the frontier of interstellar space. In recent months, it has looked like a computer glitch could spell the end of this iconic mission. The team is hopeful, though. A new transmission appears to have relevant data that could help engineers identify and fix the error.

Late last year, Voyager 1 began sending garbled data back home due to a problem with its flight data subsystem (FDS) computer. The probe was built with a backup FDS, but that device failed in 1981. The team at NASA's Jet Propulsion Laboratory (JPL) has tried numerous fixes, none of which have worked.

Voyager 1 was the first human-made object to leave the solar system in 2013, followed a few years later by Voyager 2. Communication becomes more difficult day by day as the lag between transmissions and replies increases. Each time JPL engineers attempt to communicate with the Voyager spacecraft, they have to wait 22.5 hours for the signal to reach the probe and another 22.5 hours for the reply. That has made troubleshooting the data corruption issue, which began last November, all the harder.

On March 1, the team sent what is known as a "poke" command to Voyager 1. This operation instructs the probe to run through different sequences in its software package. The intention is to work around possible data corruption that prevents normal sequences from working. When the reply came on March 3, the team noted an unusual signal. The new data block was not in the standard Voyager format, so the team initially believed it was just more random junk. An engineer working on the agency’s Deep Space Network, communicating with Voyager and other missions, realized it was important.

Voyager's flight data subsystem (FDS) is one of three computers on the spacecraft. Credit: NASA

According to NASA, the team confirmed on March 10 that the decoded signal contained a full readout of Voyager 1's FDS memory. That includes a full copy of FDS computer code and the active variables that change based on commands or spacecraft status. There is also a copy of science and engineering data for downlink.

The JPL team now has a potential path forward. Engineers are comparing the new FDS readout to data sent back last year before the glitch. This could help nail down the issue and devise a fix. NASA cautions, however, that this won't happen right away. If this data points to a solution, JPL will want to be sure before attempting to fix a spacecraft 15 billion miles (24 billion kilometers) from Earth.