It’s been 47 years since the twin Voyager spacecraft started their historic mission. Having travelled through interstellar space, farther from Earth than any other human-made objects, their nuclear batteries are depleting — but NASA is taking measures to squeeze as much life out of the aging probes as possible.
The Voyagers’ radioisotope power system loses around 4 watts each year, so to preserve power, NASA engineers have been shutting down some of the science instruments carried by each probe. Voyager 1’s cosmic ray subsystem experiment was turned off on February 25th. When the low-energy charged particle instrument aboard Voyager 2 is shut down on March 24th, both spacecraft will have three out of the ten identical science instruments they launched with remaining operational.
“Electrical power is running low,” said Voyager project manager, Suzanne Dodd. “If we don’t turn off an instrument on each Voyager now, they would probably have only a few more months of power before we would need to declare end of mission. The Voyagers have been deep space rock stars since launch, and we want to keep it that way as long as possible.”
Instruments aboard the probes have been turned off for this purpose before. The only equipment that remained powered after both spacecraft had completed their final flyby of the solar system’s gas giants was prioritized to collect data about the heliosphere and interstellar space. With the latest shutdowns, NASA says the Voyager probes should have enough power to keep operating for another year.
The Voyagers have greatly surpassed the lifespan expected from their two-planet exploration mission. Both were only built to last five years, but the scientific data they’ve collected since is unique, motivating NASA to extend their chances of survival. The agency managed to fix Voyager 1 when it stopped transmitting viable data in 2023, 15 billion miles away from Earth, bringing it back online again in June last year.
Future energy saving plans include turning off the low-energy charged particle instrument aboard Voyager 1 next year, and Voyager 2’s cosmic ray subsystem in 2026. With these efforts, NASA engineers believe the two probes could continue operating with at least one science instrument into the 2030s — providing unforeseen challenges don’t arise.
“Every minute of every day, the Voyagers explore a region where no spacecraft has gone before,” said Voyager project scientist Linda Spilker. “That also means every day could be our last. But that day could also bring another interstellar revelation. So, we’re pulling out all the stops, doing what we can to make sure Voyagers 1 and 2 continue their trailblazing for the maximum time possible.”
