After Nearly 50 Years in Deep Space, Voyager 1 Still Phones Home—With a 23-Hour Delay

NASA’s Voyager 1, the farthest human-made object in existence, continues to transmit data from interstellar space despite being launched in 1977—nearly half a century ago.

The probe, which has traveled 15.85 billion miles from Earth, now requires 23 hours for its signals to reach mission control at NASA’s Jet Propulsion Laboratory (JPL), a delay that will grow to a full day in November when it reaches one light-day distance.

Voyager 1 was originally tasked with flybys of Jupiter and Saturn, where it discovered new rings and moons, but its mission expanded dramatically after it crossed into interstellar space in 2012.

Powered by three radioisotope thermoelectric generators (RTGs) that produced 470 watts at launch, the spacecraft now generates just 230 watts due to plutonium decay, forcing JPL to shut down instruments to conserve energy. Only the magnetometer and plasma wave subsystem remain operational.

To prevent thruster lines from freezing—a failure that would sever Earth contact—JPL is testing a power-saving maneuver called “Big Bang,” which could save 10 watts by reallocating heat to critical systems. If successful, the probe and its twin, Voyager 2, could remain functional into the 2030s.

Voyager 1 carries the Golden Record, a time capsule of humanity’s greetings in 55 languages, sounds of nature, and encoded messages from U.S.

President Jimmy Carter and UN Secretary General Kurt Waldheim, intended for any extraterrestrial intelligence it might encounter.

Though its scientific instruments are fading, Voyager 1 remains humanity’s first ambassador to the stars, a relic of 1970s engineering still pushing the boundaries of deep-space exploration.