NASA's Voyager 1 spacecraft is back in action and conducting normal science operations for the first time since the veteran probe began spouting gibberish at the end of 2023.

All four of the spacecraft's remaining operational instruments are now returning usable data to Earth, according to NASA.

Some additional work is needed to tidy up the effects of the issue. Engineers need to resynchronize the timekeeping software of Voyager 1's three onboard computers to ensure that commands are executed at the correct times. Maintenance will also be performed on the digital tape recorder, which records some data from the plasma instrument for a six-monthly downlink to Earth.

As the 50th anniversary of Voyager 1's launch rapidly approaches, and with the probe now 15 billion miles (24 billion kilometers) from Earth, restoring functionality is quite an engineering feat.

Voyager 1's woes began in November 2023, when the spacecraft stopped transmitting usable data back to Earth. Rather than engineering and science data, NASA found itself faced with a repeating pattern of ones and zeroes, as though the spacecraft was somehow stalled.

Engineers reckoned the issue lay with the Flight Data System (FDS) and in March sent a command - dubbed a "poke" - to get the FDS to try some other software sequences and thus circumvent whatever was causing the problem.

The result was a complete memory dump from the computer, which allowed engineers to pinpoint where the corruption had occurred. It appeared that a single chip was malfunctioning, and engineers were faced with the challenge of devising a software update that would work around the defective hardware.

Usable engineering data began to be returned later in April, and in May the mission team sent commands to instruct the probe to keep science data flowing. The result was that the plasma wave subsystem and magnetometer instrument began sending data immediately. According to NASA, the cosmic ray subsystem and low energy charged particle instrument required a little more tweaking but are now operational.

The rescue was made all the more impressive by the fact that it takes 22.5 hours for a command to reach Voyager 1 and another 22.5 hours for a response to be received on Earth.

How much longer the Voyagers can continue to function is open to conjecture. The power supplies are gradually degrading, and engineers have been turning off non-essential systems to eke out dwindling resources for as long as possible.

Due the engineers' efforts, there is a very good chance that one or both Voyagers will continue to be operational by the time the 50th anniversary of the mission's launch rolls around in 2027.

A fitting tribute to those who designed the spacecraft, and the mission's first project scientist, Ed Stone, who died recently at the age of 88. ®

https://www.theregister.com//2024/06/14/voyager_1_restored/