WASHINGTON — Four instruments on NASA’s Voyager 1 spacecraft are returning science data for the first time since a computer failure last November, as scientists hope to keep the mission going for another decade.
NASA’s Jet Propulsion Laboratory announced on June 13 that four instruments on the spacecraft that measure plasma waves, magnetic fields and particles in interstellar space have started returning data again. Two of the instruments launched immediately after commands were sent to the spacecraft on May 19, while the other two required what JPL called “some additional work” to resume operations.
The instruments have been offline since November 2023, when a computer malfunction on board the spacecraft caused it to return garbled data. The “Tiger Team” of engineers traced the problem to a damaged memory chip in one of the spacecraft’s computers and rewrote the software to avoid using that chip. The effort restored communications with the spacecraft in April.
“The Tiger team was able to reprogram and relocate that code, first for the engineering part of the data modes coming from the spacecraft,” Voyager project scientist Linda Spilker said at the Outer Planets Analysis Group meeting on June 13, where she announced the instruments were working again. “We are now acquiring science data from all four of Voyager 1’s science instruments.”
“This is the first flight software update performed on a spacecraft in interstellar space,” she added. “The last time we did a lot with the flight software was before it launched. Voyager 1 launched in 1977.
With the spacecraft’s computer now operational again, the key factor limiting the lifespan of Voyager 1 and its twin, Voyager 2, is the declining performance level. Each spacecraft loses about four watts per year, a combination of the decay of their plutonium-238 power supplies and the degradation of the thermocouples that convert the heat from that decay into power.
Controllers managed the declining performance by turning off non-essential systems, including heaters that kept instruments and other components warm. “What’s happening is the spacecraft is getting cold, so we have both energy and thermal concerns,” Spilker said.
At some point, she said, the mission would have to start shutting down instruments on its own, but she hoped the spacecraft could continue operating possibly into the next decade.
“With luck, it might be possible to continue the Voyager spacecraft collecting data well into the 2030s,” she said. If Voyager 1 reaches 2035, it will be 200 AU, or about 30 billion kilometers, from the Sun. It is currently more than 24 billion kilometers from the Sun.
“Right now we’re focused on getting to 2027,” she said. “That will be 50Thursday anniversary of the launch of both Voyager spacecraft.
The announcement that Voyager 1’s instruments are returning data again came two days after JPL announced the departure of Ed Stone, who served as Voyager’s project scientist from the mission’s inception in 1972 until 2022, when he retired and was replaced by Spilker. Stone, a professor of physics at Caltech, also served as Caltech’s director from 1991 to 2001.
“Ed Stone often said during the planetary flyby phase that we had a rare opportunity with planetary alignment, and we took advantage of it,” she said of the “Grand Tour” trajectory that allowed the Voyager spacecraft to fly by Jupiter, Saturn, Uranus and Neptune. “I would add that both Voyagers still have rare opportunities and Ed will continue to take advantage of them.