Voyager Probes Conserve Power to Extend Their Journey into Interstellar Space
Pasadena, California — NASA’s twin Voyager probes, launched 47 years ago, are shutting down specific science instruments to conserve power and extend their historic missions. Voyager 1 and Voyager 2, currently traversing uncharted interstellar space, will each reduce their scientific operations, with Voyager 1 powering down its cosmic ray subsystem on February 25 and Voyager 2 shutting off its low-energy charged particle instrument on March 24. The decision aims to preserve the probes’ energy and prolong data collection from their remaining instruments.
“The Voyagers have been deep space rock stars since launch, and we want to keep it that way as long as possible,” said Suzanne Dodd, Voyager project manager at NASA’s Jet Propulsion Laboratory (JPL). “But electrical power is running low. 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.”
Since their launch in 1977, both probes have consistently lost power—approximately 4 watts per year—due to their reliance on a radioisotope power system that generates electricity from decaying plutonium. Originally outfitted with ten science instruments, the probes now retain only three operational instruments each to continue their exploration beyond the solar system.
Voyager 1 and Voyager 2 reached interstellar space in 2012 and 2018, respectively, becoming the most distant human-made objects. Voyager 1 is currently over 15 billion miles (25 billion kilometers) from Earth, while Voyager 2 is more than 13 billion miles (21 billion kilometers) away, racing further into the cosmos.
The cosmic ray subsystem experiment onboard Voyager 1, which ceased operations last week, consisted of a trio of telescopes that studied cosmic rays originating from the sun and Milky Way galaxy. This data was essential for determining the moment Voyager 1 exited the heliosphere—the protective bubble of solar winds and magnetic fields surrounding our solar system—and entered interstellar space.
Voyager 2’s low-energy charged particle instrument is designed to measure ions, electrons, and cosmic rays, and it will be deactivated later this month. This instrument provided scientists with valuable information about particle interactions in the heliosphere and interstellar medium, further carrying forth the legacy of the Voyager program.
Linda Spilker, a Voyager project scientist at JPL expressed, “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 as long as possible.”
The ongoing efforts to conserve power include plans for future shut-downs of additional instruments. Voyager 1’s low-energy charged particle instrument is scheduled for deactivation in 2026, followed by Voyager 2’s cosmic ray subsystem. Despite the challenges, NASA engineers are optimistic that with these measures, at least one scientific instrument could remain operational into the 2030s.
The Voyager mission has exceeded expectations, gathering invaluable data that not only extends our understanding of the solar system but also contributes to heliophysics. Patrick Koehn, Voyager program scientist at NASA Headquarters noted, “Every bit of additional data we have gathered since then is not only valuable bonus science for heliophysics, but also a testament to the exemplary engineering that has gone into the Voyagers—starting almost 50 years ago.”
As they continue their journeys beyond known space, Voyager 1 and Voyager 2 remain dedicated to discovering secrets of interstellar space, despite the impending power challenges that lay ahead.
