WASHINGTON — The 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 running for another decade.
NASA’s Jet Propulsion Laboratory announced June 13 that the spacecraft’s four instruments, which measure plasma waves, magnetic fields and particles in interstellar space, have begun 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 “additional work” to resume operations.
The instruments have been offline since November 2023, when a computer malfunction aboard the spacecraft caused it to return garbled data. A “tiger team” of engineers traced the problem to a faulty memory chip in one of the spacecraft’s computers and rewrote the software to avoid using that chip. That effort restored communications with the spacecraft in April.
“The Tiger team was able to reprogram and move that code, first for the engineering part of the data modes coming from the spacecraft,” Voyager project scientist Linda Spilker said at a June 13 meeting of the Exoplanet Analysis Group, where she announced the tools were working again. “We are now receiving science data from all four Voyager 1 science instruments.”
“This is the first flight software update done on a spacecraft in interstellar space,” she added. “The last time we really did much with the flight software was before launch.” Voyager 1 launched in 1977.
With the spacecraft’s computer now operational again, the key factor limiting the lives of Voyager 1 and its twin, Voyager 2, is declining power levels. Each spacecraft loses about four watts per year, a combination of the decay of their plutonium-238 power supplies and the breakdown of the thermocouples that convert the heat from that decay into power.
Controllers managed the declining power by turning off non-essential systems, including heaters that kept instruments and other components warm. “What happens is the spacecraft gets cold, so we have both a power concern and a thermal concern,” Spilker said.
At one point, she said the mission would have to start shutting down the instruments themselves, but she hoped the spacecraft could continue operating for perhaps the next decade.
“With any luck, it may be possible for the Voyager spacecraft to continue retrieving data into the 2030s,” she said. If Voyager 1 arrives in 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.
“Our focus right now is to get to 2027,” she said. “It will be the 50sth anniversary of the launch of the two Voyager spacecraft.
The announcement that Voyager 1’s instruments are returning data again came two days after JPL announced the death of Ed Stone, who was Voyager’s project scientist from the mission’s launch 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 flyby phase that we had a rare opportunity with the alignment of the planets 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 capabilities, and Ed will continue to take advantage of them.”
