Voyager 1 Nears One Light-Day From Earth, Marking a New Distance Record in Interstellar Space

On Wednesday, November 18, 2026, a radio signal leaving NASA's Voyager 1 will need exactly 24 hours, traveling at the speed of light, to reach Earth. That makes it one light-day, a distance of more than 26 billion kilometres, and no human-made object has ever been this far away. The spacecraft was launched 49 years ago.

The milestone is still a long way from the next ones. NASA estimates another 18,000 years before Voyager 1 covers a full light-year, and more than twice that before it comes anywhere near another star. Its twin, Voyager 2, was launched two weeks after Voyager 1 in 1977, but it will not reach the one light-day mark until 2035. Both probes are moving toward different points in space at about 61,000 kph.

Voyager 1's early record is well known. It swept past Jupiter in 1979 and Saturn in 1980, to the delight of scientists, and then left the solar system. In 2012 it reached what NASA defines as interstellar space, the region between star systems. Voyager 2 visited Jupiter and Saturn as well, then Uranus and Neptune, and sent back striking photos from each. It entered interstellar space in 2018.

Both craft are still working. Almost every day they send back details of an environment no spacecraft had explored before: the strength and direction of the magnetic field, along with readings on pressure, dust and galactic cosmic rays. Project manager Suzanne Dodd, who has worked with the Voyagers since 1984, compares them to weather satellites. She calls Voyager 1 Earth's ambassador among the stars and a source of a "sense of wonder" at home. "It's a national treasure," she told The Associated Press. "Really extraordinary."

Keeping them going takes a small crew. A skeleton flight control team at NASA's Jet Propulsion Laboratory in Pasadena, California, sends commands about once a week. Activity picks up when problems arise, and a couple of retirees who once worked on the project sometimes help. The probes have had the sporadic troubles of old age. In September, controllers finished the latest effort to conserve power on the plutonium-powered Voyager 1. In October they briefly lost contact with it, and they are still trying to work out why communication was disrupted. Dodd likens the spacecraft to "the little engine that could."

Voyager 1 has collected several Guinness World Records along the way. Besides going farther than any other human-made object, it took the most distant picture of Earth in 1990, the "Pale Blue Dot," seen from beyond Neptune. Cornell University astronomer Carl Sagan, part of the imaging team, introduced the image that year: "On that blue dot, that's where everyone you know and everyone you ever heard of and every human being who ever lived, lived out their lives. It's a very small stage in a great cosmic arena."

Sagan also drove the creation of the Golden Record. Each Voyager carries a 30-centimetre gold-plated phonographic record with greetings in 55 languages, plus images and diagrams. Sagan included the voice of his son Nick, then 6, saying "Hello from the children on Planet Earth," and added a stylus and instructions for any finder. Dodd calls it a time capsule of life on Earth in 1977 and hopes someone finds it perhaps 1,000 years from now. Bill Nye of the Planetary Society, which Sagan co-founded in 1980 and who died in 1996, noted that most people alive today were not born at launch, yet everyone on Earth has been touched by the missions.

NASA is asking people to mark the occasion after sunset on Tuesday, November 17. Using a phone or flashlight, they are invited to flash the Morse code for V-G-R, Voyager's call sign, into the night sky. Meanwhile, engineers continue to investigate the October loss of contact.