WASHINGTON – The four instruments on NASA’s Voyager 1 spacecraft are returning scientific data for the first time since a computer malfunction last November, as scientists hope to keep the mission going for another decade.
NASA’s Jet Propulsion Laboratory announced June 13 that four instruments on the spacecraft, which measure plasma waves, magnetic fields and particles in interstellar space, have begun returning data again. Two of the instruments started 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 had 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 ship’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 relocate that code, first for the engineering part of the data modes coming from the spacecraft,” Linda Spilker, Voyager project scientist, said at a June 13 meeting of the Analysis Group of the Outer Planets, where she announced the instruments were working again. “We are now receiving science data from all four of Voyager 1’s science instruments.”
“This is the first flight software update done on a spacecraft in interstellar space,” she added. “The last time we did much with the flight software was before take off.” Voyager 1 was launched in 1977.
With the spacecraft’s computer now working again, the main life-limiting factor for Voyager 1 and its twin, Voyager 2, is declining power levels. Each spacecraft loses about four watts a year, a combination of the decay of the plutonium-238 power supply and the degradation of the thermocouples that turn the heat from that decay into power.
Controllers managed the power drop by turning off non-essential systems, including heaters that had been keeping instruments and other components warm. “What’s happening is the spacecraft is getting cold, so we have an energy perturbation and a thermal perturbation,” Spilker said.
At some point, she said the mission will have to start turning off the instruments themselves, but she hoped the spacecraft could continue to operate possibly into the next decade.
“With a bit of luck, it may be possible for the Voyager spacecraft to continue receiving 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.
“Right now, our focus is to get to 2027,” she said. “This will be 50th anniversary of the launch of both Voyager spacecraft.”
The announcement that Voyager 1’s instruments were returning data again came two days after JPL announced the death of Ed Stone, who served as 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 would often say during the planetary 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 enabled 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 seize them.”