Voyager 2 will not reach the same mark until 2035

NASA’s Voyager 1 will cross one light-day from Earth on Wednesday, a first for humanity and a milestone 49 years in the making. The spacecraft will be more than 16 billion miles (26 billion kilometers) out, and its radio signals will take exactly 24 hours, traveling at the speed of light, to reach Earth.

NASA put the remaining distance in perspective: the agency is looking at another 18,000 years before Voyager 1 achieves a full light-year, and more than double that before it comes near another star.

Suzanne Dodd, NASA’s project manager for the mission, sees Voyager 1 as Earth’s ambassador hurtling between stars while providing a “sense of wonder” on the home front.

“It’s a national treasure,” Dodd told The Associated Press. “Really extraordinary.”

To mark the moment, NASA is asking people everywhere to grab a phone or a flashlight after sunset Tuesday and create a wave of golden light, using Morse code to spell the letters V-G-R — Voyager’s call sign — into the night sky.

Despite sporadic problems typical of old age, Voyager 1 and its twin Voyager 2 continue to send back science and engineering data as they travel at 38,000 mph (61,000 kph) toward different points in space. Voyager 2 launched two weeks before its sibling in 1977, but will not reach the one light-day mark until 2035.

Voyager 1 swept past Jupiter and Saturn in 1979 and 1980 before exiting the solar system, and it reached what NASA defines as interstellar space — the region between star systems — in 2012. Voyager 2 visited those two planets plus Uranus and Neptune, also sending back photos, before entering interstellar space in 2018.

Almost every day, the Voyagers beam back details about their never-before-explored environment: the strength and direction of the magnetic field, along with information about surrounding pressure, dust and galactic cosmic rays. Dodd, who has worked with the Voyagers since 1984, said they are a bit like weather satellites.

A skeleton flight control team at NASA’s Jet Propulsion Laboratory in Pasadena, California, sends commands about once a week. The operation ramps up when spacecraft problems arise, with help sometimes coming from a couple of retirees who once worked on the project.

In September, controllers completed the latest power-conserving effort for the plutonium-powered spacecraft. In October they briefly lost contact with it, and they are still trying to figure out why communication was disrupted.

Dodd said all the expertise and love have kept Voyager 1 chugging along like “the little engine that could,” while racking up entries in Guinness World Records. Besides venturing farther than any other human-made object, Voyager 1 in 1990 snapped the most distant picture of Earth: the iconic “Pale Blue Dot,” seen from beyond Neptune.

“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,” Cornell University astronomer Carl Sagan, part of the imaging team, said as he introduced the picture to the world in 1990.

Bill Nye of the Planetary Society said in a statement that while the majority of people alive today were not yet born when the Voyagers launched, “all of us — everyone on Earth — have been touched by these missions.” The society was co-founded in 1980 by Sagan, who died in 1996, and the Golden Record also resulted from Sagan’s effort.

Each Voyager carries a 12-inch (30-centimeter) gold-plated phonographic record containing greetings in 55 languages as well as images and diagrams. Sagan included the voice of his son Nick, then 6: “Hello from the children on Planet Earth.” He added a stylus and instructions for any finders-keepers out there.

“It’s a time capsule of life on Earth from 1977,” Dodd said. “I hope something, someone, finds it maybe 1,000 years from now.”