On Friday, April 17, 2026, engineers at NASA’s Jet Propulsion Laboratory (JPL) sent commands to deactivate one of the few remaining science instruments aboard Voyager 1. The decision to shut down the Low-energy Charged Particles (LECP) experiment was made to conserve the spacecraft’s dwindling power reserves, ensuring that the most distant human-made object can continue its historic journey through interstellar space for as long as possible.
Voyager 1 is currently more than 15.7 billion miles (25.3 billion km) from Earth. At this extreme distance, it takes approximately 23.5 hours for a radio signal traveling at the speed of light to reach the probe, meaning mission controllers must wait nearly two full days to confirm the success of any command.
Managing a Decades-Old Nuclear Power Source
Voyager 1 relies on a radioisotope thermoelectric generator (RTG), which converts the heat from decaying plutonium-238 into electricity. Because the plutonium decays over time, the spacecraft’s power output decreases by about 4 watts every year. After nearly 49 years in the harsh environment of space, these power margins have become razor-thin.
The decision to power down the LECP was prompted by an unexpected drop in power levels during a routine roll maneuver in late February 2026. This dip brought Voyager 1 dangerously close to triggering its automatic “undervoltage” fault protection—a self-preservation mode that would have shut down critical systems and required a risky, multi-day recovery process. To stay ahead of this threshold, engineers chose to manually retire the LECP, which had been operating almost continuously since the probe’s launch in 1977.
Preserving Interstellar Science
The LECP was a vital tool for mapping the frontier beyond our solar system, measuring ions, electrons, and cosmic rays to detect the invisible pressure fronts of interstellar space. While its shutdown is a loss for science, the move preserves power for the two remaining active instruments:
- The Magnetometer (MAG): Measures the magnetic fields of the interstellar medium.
- The Plasma Wave Subsystem (PWS): “Listens” for density changes in the interstellar plasma.
By prioritizing these two sensors, NASA ensures the mission continues to report on the fundamental physics of the universe from a location no other spacecraft has reached. Interestingly, a small motor used to rotate the LECP sensor will remain powered on; at just 0.5 watts, it is left running to prevent it from seizing, leaving a slim possibility of restarting the instrument if power levels are stabilized in the future.
The “Big Bang” Strategy for the 2030s
The shutdown of the LECP provides Voyager 1 with roughly one year of “breathing room.” During this time, the team is finalizing a high-stakes power management plan internally known as the Big Bang. This strategy involves swapping a group of older, power-hungry components for lower-power alternatives all at once to keep the spacecraft’s vital electronics warm enough to function.
NASA plans to test the Big Bang procedure on Voyager 2 in May and June 2026, as the twin probe is closer to Earth and has slightly more power to spare. If successful, the same fix will be applied to Voyager 1 no sooner than July 2026. The ultimate goal is to keep at least one science instrument operational on both spacecraft well into the 2030s.
One Light-Day Away
Even as its power fades, Voyager 1 continues to set records. On November 15, 2026, the spacecraft is projected to reach a symbolic distance of exactly one light-day from Earth—approximately 16.1 billion miles (25.9 billion km). At that point, a message sent from NASA’s Deep Space Network will take a full 24 hours to reach the probe, and another 24 hours for the response to return. This mission remains a testament to the ingenuity of the engineers who keep a 1970s-era machine functioning in the deep silence of interstellar space.
