On April 17, NASA mission engineers sent commands to deactivate the Low-energy Charged Particles experiment (LECP), on Voyager 1, the historic space probe launched alongside Voyager 2 in 1977 to study Jupiter and Saturn.
Now more than 15 billion miles from Earth – easily the most distant human-made object ever built – Voyager 1 is running out of power and its engineers hope shutting down one of its last science instruments can keep the spacecraft operating.
Both probes are powered by a radioisotope thermoelectric generator, which converts heat from decaying plutonium into electricity. While there was more than enough electricity to fuel them through their original five-year journey, they have continued to lose about four watts annually. After nearly five decades, Voyager 1 and 2 have been left with extremely slim power reserves.
NASA engineers’ close management of these reserves have prevented the probes from getting too cold while preserving enough energy for them to continue their mission. But Voyager 1 is in a particularly precarious situation.
On Feb. 27, its power levels suddenly declined during a routine maneuver, nearly triggering a shutdown that would have forced engineers into a risky recovery process. Kareem Badaruddin, Voyager mission manager at NASA’s Jet Propulsion Laboratory (JPL), wrote in a statement, “While shutting down a science instrument is not anybody’s preference, it is the best option available.”
The Voyager science and engineering teams have been preparing for the inevitable for years, having long agreed on the order in which to switch off certain scientific instruments on the probes. After the Cosmic Ray Subsystem (CRS) was shut down on Voyager 1 to conserve power on Feb. 25, 2025, its LECP was next on the list.
The LECP has measured ions, electrons and cosmic rays from our solar system and the rest of the galaxy. Voyager 2’s LECP was turned off for power conservation on March 24, 2025.
Voyager 1 currently has two operational scientific instruments — the Magnetometer (MAG), which measures magnetic fields, and Plasma Wave Subsystem (PWS), which listens for plasma waves. NASA engineers believe shutting down the LECP will buy the probe about a year of “breathing room,” during which they intend to finalize a plan they call “the Big Bang.”
Hoping to extend the Voyager missions, the team plans to perform a coordinated substitution of several powered devices for lower-power alternatives. They will implement the plan during May and June and will start with Voyager 2, as it has more power to spare and is closer to Earth.
If the operation is successful for Voyager 2, NASA will do the same for Voyager 1 by July 2026. They may even be able to turn its LECP back on.
Engineers hope to keep at least one scientific instrument operational on each probe into the 2030s as the probes continue to the edge of our solar system and beyond.
