Launched in 1977, NASA’s Voyager 1 and Voyager 2 spacecraft have traveled farther than any other man-made objects in history. They have sent back invaluable scientific data, helping us better understand the outer planets and interstellar space. However, after nearly 50 years, the spacecraft are running low on power. To keep them operational, NASA has started shutting down some of their scientific instruments.
The Voyager spacecraft are powered by radioisotope thermoelectric generators (RTGs). These devices convert decaying plutonium-238 into electricity. However, the power supply decreases by about four watts every year. As a result, NASA has had to make tough decisions to keep the spacecraft running as long as possible.
In February 2025, mission engineers turned off Voyager 1’s Cosmic Ray Subsystem, which measured cosmic rays from deep space. On March 24, 2025, Voyager 2’s Low-Energy Charged Particle Instrument was also scheduled for shutdown. By shutting down these instruments, NASA hopes to conserve enough power to keep other instruments running for several more years.
The instruments that NASA has shut down have made incredible discoveries over the years. Voyager 1’s Cosmic Ray Subsystem played a major role in confirming that the spacecraft had left the heliosphere—the protective bubble created by the Sun—and entered interstellar space in 2012. This was a historic milestone in space exploration.
Voyager 2’s Low-Energy Charged Particle Instrument measured ions, electrons, and cosmic rays from both our solar system and interstellar space. It provided critical data when Voyager 2 crossed into interstellar space in 2018. These instruments have vastly exceeded their expected lifetimes, operating for decades longer than originally planned.
Even though some instruments are shutting down, each Voyager spacecraft still has three scientific instruments active. NASA scientists believe that at least one instrument on each spacecraft could continue to function into the 2030s. However, the spacecraft are now so far from Earth—over 15 billion miles for Voyager 1 and 13 billion miles for Voyager 2—that it takes more than nineteen hours for signals to travel one way. Communicating with them is becoming increasingly difficult, according to The Associated Press.
Patrick Koehn, Voyager program scientist at NASA Headquarters, highlighted the importance of keeping the mission going. “The Voyager spacecraft have far surpassed their original mission to study the outer planets,” he said in an article published in Futurism. 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 nearly 50 years ago and continuing to this day.”
The Voyager mission is one of the most successful space explorations in history. Although shutting down instruments is a difficult choice, it is necessary to extend the life of these legendary spacecraft. As they continue their journey through interstellar space, they will keep sending back data that no other mission has ever collected. Even as their power fades, the Voyagers will remain symbols of human curiosity and engineering brilliance.
