NASA powers down Voyager 1 instrument to conserve energy

NASA shut down another science instrument on Voyager 1 in April to stretch the life of the farthest human-made object ever launched. The move was part of a long-running power-management effort as the spacecraft’s radioisotope power source continues to weaken with age. Voyager 1 crossed into interstellar space on Aug. 25, 2012, and remains active more than four decades after its 1977 launch. NASA says the spacecraft is still returning data from the region beyond the Sun’s heliosphere. ### Which instrument did NASA turn off? NASA’s Jet Propulsion Laboratory said engineers sent commands on April 17 to shut down Voyager 1’s Low-Energy Charged Particles experiment, or LECP. The instrument had operated almost continuously since launch and measured low-energy charged particles including ions, electrons and cosmic rays from the solar system and the galaxy. (jpl.nasa.gov) The April shutdown was not the first recent cut. In February 2025, NASA turned off Voyager 1’s cosmic ray subsystem experiment as part of the same effort to manage declining electrical output. That left three science instruments still operating on the spacecraft after the latest step. ### Why does Voyager 1 keep losing usable power? Voyager 1 is powered by a radioisotope thermoelectric generator, which converts heat from decaying plutonium into electricity. (jpl.nasa.gov) NASA has said that power drops gradually over time, forcing engineers to decide which heaters, subsystems and instruments can be shut down while keeping the spacecraft healthy and scientifically useful. (jpl.nasa.gov) A 2022 NASA update said a revised power strategy could delay the need to shut off one science instrument until 2026. That forecast has now played out, with the LECP experiment taken offline this year rather than earlier. NASA said at the time that shutting down one instrument would not end the mission and that additional years of operation remained possible if the spacecraft stayed healthy. (jpl.nasa.gov) ### How far away is Voyager 1 now? Voyager 1 is the most distant spacecraft ever built, according to NASA’s mission pages. NASA says it entered interstellar space at about 122 astronomical units from the Sun, equivalent to about 11 billion miles, or 18 billion kilometers, at the time of crossing in 2012. NASA’s current mission material says Voyager 1 continues to travel through interstellar space, and outside reports have put its present distance at more than 24 billion kilometers from Earth. (jpl.nasa.gov) Because of that distance, one-way radio signals now take more than 22 hours to arrive. NASA described similar communication delays in earlier engineering updates, when a round trip already took roughly two days. (science.nasa.gov) ### What science is still coming back? Three instruments remain active on Voyager 1 after the April shutdown, NASA said. Those surviving instruments continue to sample magnetic fields, plasma waves and energetic particles in interstellar space, allowing scientists to study conditions outside the heliosphere. Voyager 1’s importance now is less about planetary flybys than about long-duration measurements from a place no other functioning spacecraft has reached. (science.nasa.gov) NASA said the mission still provides unique observations of the interstellar medium, the sparse gas, dust and charged particles between stars. ### What happens next for the mission? NASA’s Voyager team has said power-management decisions will continue as electrical output declines. (jpl.nasa.gov) The agency has been making those tradeoffs for years, switching off heaters, backup systems and selected instruments to preserve communications and the remaining science payload. NASA’s Voyager mission status and JPL news pages are expected to show the next milestones, including any further instrument shutdowns on Voyager 1 or Voyager 2. (science.nasa.gov) Voyager 2 remains active as well, with its own power-saving schedule shaped by the same slow loss of onboard electricity. (jpl.nasa.gov 1) (jpl.nasa.gov 2)