Almost 50 years after it launched, NASA has deliberately shut down one of Voyager 1’s remaining science instruments — not because the mission failed, but to keep the spacecraft alive longer.
Voyager 1 blasted off from Cape Canaveral on Sept. 5, 1977, atop a Titan‑Centaur rocket. About the size of a small car, it weighs roughly 1,797 pounds and still uses a 12‑foot dish to talk to Earth. Originally designed for a five‑year Grand Tour of the outer planets, Voyager 1 has operated nearly continuously for decades and far exceeded its planned lifetime.
The probe returned groundbreaking results during its planetary flybys: Jupiter in 1979 (including the first observations of active volcanism on the moon Io) and Saturn in 1980, where a close pass of Titan redirected Voyager 1 out of the solar system’s plane and onto its long journey toward interstellar space. In 1990 its mission was extended as the Voyager Interstellar Mission, and on Aug. 25, 2012, it crossed the heliopause — the boundary where the Sun’s influence gives way to interstellar space — becoming the first human‑made object to do so.
Today Voyager 1 is well over 15 billion miles from Earth; radio signals take more than 23 hours to travel one way. It carries no solar panels and relies on a radioisotope thermoelectric generator (RTG) that converts heat from decaying plutonium into electricity. The RTG’s output declines at roughly 4 watts per year, and after decades that gradual loss has become mission‑critical.
A routine maneuver in late February caused an unexpected power drop that nearly triggered an automatic fault‑protection shutdown. That automatic response would have been time‑consuming and risky to resolve, so mission engineers chose a preventative step instead. On April 17 they sent commands to turn off the Low‑Energy Charged Particles experiment (LECP), which measures ions, electrons and cosmic rays to help map the heliosphere and the interstellar environment. The LECP on Voyager 2 was powered down in March 2025.
The Voyager team long ago agreed on an order for powering down instruments to conserve energy while preserving the most valuable measurements. Shutting down LECP is the next step in that plan. According to mission management, deactivating the instrument is expected to free enough power to extend Voyager 1’s useful life by roughly another year. After the change, Voyager 1 still has two functioning science instruments: a plasma‑wave detector and a magnetometer.
The team is also preparing a larger power‑saving maneuver nicknamed “the Big Bang,” which involves replacing several older, higher‑power components with lower‑power alternatives in a coordinated sequence. Tests planned for Voyager 2 in May and June 2026 will help determine whether the procedure can be safely applied to Voyager 1 as soon as July. If the swap works, there is a small chance some instruments, including LECP, could be returned to service.
Engineers’ goal is to keep at least one instrument operating on each Voyager well into the 2030s so the probes can continue sending unique data from regions of space no other spacecraft have sampled. Turning off a piece of history is a difficult choice, but it’s being done to preserve the mission’s ability to explore farther for as long as power allows.