NASA has turned off one of Voyager 1’s remaining science instruments to stretch the spacecraft’s life rather than because of a failure. Launched in 1977 for a five-year tour, Voyager 1 is now the most distant human-made object and has been operating nearly continuously for almost 49 years.
Voyager 1 launched from Cape Canaveral on Sept. 5, 1977, aboard a Titan‑Centaur. The roughly 1,797‑pound probe carries a 12‑foot high‑gain antenna for communications and was built at JPL. Its original mission took advantage of a rare planetary alignment to visit the outer planets; Voyager 1 performed close flybys of Jupiter (March 1979) and Saturn (November 1980). The Titan encounter redirected it out of the plane of the solar system and ultimately toward interstellar space.
In 1990 the mission was extended as the Voyager Interstellar Mission to study the outer boundary of the Sun’s influence and the space beyond. On Aug. 25, 2012, Voyager 1 crossed the heliopause—the boundary where the Sun’s charged-particle wind gives way to interstellar space—becoming the first human-made object to enter that region (Voyager 2 followed in 2018).
Today Voyager 1 is more than 15 billion miles from Earth, and a radio signal takes over 23 hours to travel one way. It runs on a radioisotope thermoelectric generator (RTG) that converts heat from decaying plutonium into electricity; the RTG’s output declines by about 4 watts per year. After nearly five decades that gradual drop is becoming mission‑critical.
During a routine maneuver in late February, the probe’s power dipped unexpectedly and came close to triggering an automatic fault‑protection shutdown that would have required a lengthy, risky recovery. To avoid that outcome and preserve the spacecraft’s ability to return science, engineers at JPL followed a prearranged power‑down plan and commanded Voyager 1 to deactivate the Low‑energy Charged Particles experiment (LECP) on April 17. Voyager 2’s LECP had been turned off in March 2025.
LECP measured ions, electrons and cosmic rays, contributing to maps of interstellar structure. Shutting it down was a difficult but deliberate choice: the Voyager team had long agreed on an order for powering down instruments to conserve limited RTG power while keeping the most valuable capabilities online. According to the mission manager at JPL, turning off an instrument is never preferred, but it was the best option to keep the spacecraft healthy.
Voyager 1 now has two operational science instruments: a plasma wave sensor and a magnetometer. Engineers estimate the LECP shutdown could buy roughly another year of useful data. They are also preparing a larger energy‑saving maneuver nicknamed “the Big Bang,” a coordinated swap of several powered components to lower‑energy alternatives. Tests of that procedure on Voyager 2 are planned for May–June 2026; if successful, the same sequence could be attempted on Voyager 1 no sooner than July 2026. If it works, there’s a small chance LECP could be restored.
The goal is to keep at least one instrument running on each Voyager well into the 2030s so both spacecraft can continue sending unique measurements from regions no machine has ever explored before. Turning off a piece of Voyager’s hardware is a pragmatic step to preserve the rest of a mission that has already far outlived its original design.